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Central venous cannulation and pressure monitoring
c~LLECTIVE REVIEW cO
Central Venous Cannulation and Pressure Monitoring Robert Knopp, MD Robert H. Dailey, MD Fresno, California
Central v e n o u s p r e s s u r e (CVP) v a r i e s d i r e c t l y w i t h c i r c u l a t i n g b l o o d volume and v a s c u l a r tone a n d i n v e r s e l y w i t h right h e a r t c o m p e t e n c y . Indications for c e n t r a l c a n n u l a t i o n i n c l u d e c a r d i o r e s p i r a t o r y arrest. The t w o g e n e r a l a p p r o a c h e s to c a n n u l a t i o n o f c e n t r a l v e i n s are peripheral and central. The p h y s i c i a n ' s skill, patient's b o d y habitus, clinical circumstances, age and t h o r a c i c d e f o r m i t y all i n f l u e n c e the c h o i c e of technique. Three o f the p o s s i b l e c o m p l i c a t i o n s d i s c u s s e d are p n e u m o thorax, a r t e r i a l p u n c t u r e a n d air e m b o l u s . A c c u r a t e m e a s u r e m e n t of CVP d e p e n d s o n the p a t i e n t b e i n g s u p i n e , a p a t e n t and a c c u r a t e l y located c a t h e t e r a n d the e s t a b l i s h m e n t of a b a s e l i n e e x t e r n a l zero point.
Knopp R, Dailey RH: Central venous cannulation and pressure monitoring. 6:358-366, August, 1977. c e n t r a l v e n o u s p r e s s u r e , c a t h e r i z a t i o n .
JACEP
INTRODUCTION In 1931, F o r s s m a n ~ first catheterized the h e a r t and m e a s u r e d central venous pressure. However, it was not until A u b a n i a c 2 described t h e technique of percutaneous s u b c l a v i a n v e n i p u n c t u r e in 1952 and W i l s o n 3 refined this t e c h n i q u e ten years l a t e r that c a n n u l a t i o n of the central veins and m e a s u r e m e n t of central venous pressure were commonly used. Since that time m a n y techniques to simplify the procedure h a v e been described. The purpose of our paper is to r e v i e w cannulation of the central veins and discuss t h e p h y s i o l o g y , u s e s a n d
From the Department of Emergency Medicine, Valley Medical Center, Fresno, California. Address for reprints: Robert Knopp, MD, Valley Medical Center, 445 S. Cedar AvCane, Fresno, California 93702.
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abuses of c e n t r a l venous pressure. The e m e r g e n c y d e p a r t m e n t and the critically ill or injured p a t i e n t serve as our reference point.
PHYSIOLOGICAL CONSIDERATIONS Venous pressure arises from arterial pressure t r a n s m i t t e d t h r o u g h the cap i l l ar y bed. Cen t r al venous pressure (CVP) refers to the pressure in the large intrathoracic veins. Pressure from the superior v e n a cava or one of its v al v el ess t r i b u t a r i e s is usually w i t h i n 1 ml of r i g h t atrial pressure. 4 As a result, CVP is a m e a s u r e of t h e filling pressure of the r i g h t ventricle. 5 P e r i p h e r a l venous pressure does not correlate w.~h central venous pressure due to e x t e r n a l pressure on the veins, venospasm, and the presence of valves. 6
It is e s s e n t i a l to u n d e r s t a n d t h a t CVP is not a m easu r e of blood volu m e s t a t u s alone. CVP varies directly w i t h c i r c u l a t i n g blood v o l u m e and v a s c u l a r tone and i nve r s e l y w i t h r i g h t h e a r t competency. 1-11 It ma y be useful to t h i n k of these factors as a closed s y s t e m consisting of a pump (the heart) connected to a c o n t a i n e r (vascular capacitance) and fluid t h a t is p u m p e d t h r o u g h the c o n t a i n e r (blood volume) (Figure 1). S i n c e t h e a d v e n t of m e a s u r i n g p u l m o n a r y wedge pressure w i t h the S w a n - G a n z catheter, the accuracy of CV P has been questioned. 12-1s Left a t r i a l p r e s s u r e (LAP) and C V P do not a l w a y s move in pa r a l l e l . However, recent reports 5,14,16 h a v e erap h a s i z e d t h a t in p a t i e n t s w i t h o u t c a r d i o v a s c u l a r or severe p u l m o n a r y disease, CV P and LA P tend to correl a t e closely_ C V P a l w a y s r e f l e c t s r i g h t atrial pressure (RAP) and, in p a t i e n t s w i t h o u t cardiac or pulmon a r y disease, often reflects LAP.~5, ~ Discussions concerning the subtle d i f f er en ces b e t w e e n C V P and L A P should not obscure the fact t h a t CVP is a useful m e a s u r e m e n t . A l t h o u g h not as precise as LAP, in most situations CV P is an adequate volume ind i cat o r w h e n properly done in the a v e r a g e patient. 1~ In the e m e r g e n c y d e p a r t m e n t , m o s t p a t i e n t s c a n be a d e q u a t e l y monitored using CVP.
CENTRAL CANNULATION I n d i c a t i a n s ( T a b l e 1). A r e c e n t
358/27
addition to the indications for central c a n n u l a t i o n is cardiorespiratory atrest. E s t a b l i s h i n g a central line in the arrested p a t i e n t allows intravenous medications to be given close to t h e i r site of action and shortens the time needed to circulate the drugs. In addition, successful c a n n u l a t i o n of the central veins eliminates the need for intracardiac injections, T h e r e are o t h e r i n d i c a t i o n s for c e n t r a l c a t h e t e r i z a t i o n such as hyp e r a l i m e u t a t i o n b u t t h i s is n o t u s u a l l y performed in the emergency d e p a r t m e n t a n d therefore we have excluded it.
Contrairzdications (Table 2). The most i m p o r t a n t is a lack of experience on the p a r t of the p h y s i c i a n . Supervision by a n experienced physician d u r i n g one's first few attempts at c a n n u l a t i o n and a good working knowledge of the a n a t o m y are essential.17,ts
PITFALLS IN INTERPRETATION OF CVP MONITORING k-
CVP reflects the dynamic interrelationship between It is not an index of
cardiac action cardiac output or adequacy
The femoral vein was commonly u s e d in t h e p a s t . It lies in t h e f e m o r a l t r i a n g l e m e d i a l to t h e femoral artery j u s t below the inguihal ligament. This vessel would app e a r w e l l s u i t e d for c a n n u l a t i o n since it is easily located and has no vital s t r u c t u r e s s u r r o u n d i n g it (except for the femoral artery). It can be c a n n u l a t e d by either cutdown or percutaneously. However, frequent sepsis and thromboembolism restrict its r o u t i n e use.~,e, ? R e l a t i v e leg iram o b i l i z a t i o n is r e q u i r e d a f t e r a femoral c u t d o w n and this t e n d s to increase the chance of thrombosis. T h e r e f o r e , w h e n b e t t e r s i t e s are available, we feel that this approach should not be used. 28/359
blood volume blood volume
It indicates only how efficiently the right ventricle is clearing the venous return at the time of measurement Recognition of CVP as a function of these three major clinical variables helps to obviate the numerous pitfalls in interpretation discussed in the text. ~,-
II;ll
z . ' ~ ~. z )
~
The pitfalls and limitations of CVp monitoring can be largely circurn" vented by two refinements:
~
Vascular tone
Cardiac action
Techniques. There are two general approaches to c a n n u l a t i o n of the central veins - - peripheral and central. Each has a d v a n t a g e s and disadvantages; physicians should choose the approach that, in their hands, is the safest and technically most successful. A n e m e r g e n c y p h y s i c i a n m u s t have facility with more t h a n one approach. Body h a b i t u s , clinical circumstances (eg, cardiorespiratory arrest), age (eg, children versus adults), and thoracic deformity all influence the choice of appro ach. ',9,2o Peripheral approaches include femoral vein, basilic vein and the cephalic vein in the deltopectoral groove.
vascular tone circulatory adequacy
Blood volume
1 Observeserial CVP measurements with particular attention to CVp response following any therapeu. tic trial 2 Incorporate simultaneous assessment of cardiac output adequacy with CVP measurements. This affords very precise analysis of exist. ing cardiocirculatory dynamics
Fig. 1. Wilson and Owens (reproduced with permission). 7
Table 1 I N D I C A T I O N S FOR CENTRAL VENOUS C A N N U L A T I O Nlg,22,2s,z1,33
Table 2 CONTRAINDICATIONS17J 8 i . C o m b a t i v e patients
1. S h o c k
2. Lack of real i n d i c a t i o n
2. C a r d i o r e s p i r a t o r y arrest
3. D i s t o r t e d l a n d m a r k s
3. Lack of a d e q u a t e p e r i p h e r a l v e i n s (old c u t d o w n s , n e e d l e tracks, obesity, etc.)
4. Patients w i t h c o a g u l a t i o n d i s o r d e r s (relative)
4. Severe b u r n s 5. C e n t r a l monitoring
venous
5. I n e x p e r i e n c e a n d / o r lack of k n o w l e d g e of the a n a t o m y
pressure
6. T r a n s v e n o u s p a c e m a k e r 7. Any u n s t a b l e c a r d i o c i r c u l a to ry state
The,,rbasilic vein in the a n t i c u b i t a l fossa is our preferred approach for peripheral c a n n u l a t i o n . However, p e r c u t a n e o u s c a n n u l a t i o n h e r e is often impossible due t o v e n o u s collapse, n e c e s s i t a t i n g a cutdown at this site_ Some physicians prefer this method to central (subclavian or i n t e r n a l j u g u l a r ) c a n n u l a t i o n in the p a t i e n t w i t h h y p o v o l e m i c shock. The role of percutaneous s u b c l a v i a n or intern a l j u g u l a r in emergency situations has been challenged by some. 1s,21 They
s t a t e t h a t t h e s e p r o c e d u r e s may p r o d u c e a d d i t i o n a l complications s u c h as p n e u m o t h o r a x a n d are u n r e l i a b l e in the volume depleted patient. S u b c l a v i a n or i n t e r n a l jugular catheterization, they maintain, should be reserved for pa" tients h a v i n g pure cardiac emergen'. cies and full vessels or for patients in whom elective placement of a central line is indicated. These procedures are blind, i n v a s i v e and potentially dangerous. In t r a u m a t i c shock we believe t h a t the subclavian and espe': c i a l l y t h e i n t e r n a l j u g u l a r aF proaches are an a l t e r n a t i v e to cut" down at the basilic vein for cannulat" : ing the c e n t r a l veins. The primary a d v a n t a g e of the basilic vein cat6:8 ( A u g ) 1 9 7 7 ~ " ~ 2
d0w~ are the large volumes of fluid that can be given to a p a t i e n t w h e n iotravenous extension t u b i n g is used for the cutdown and the r e l a t i v e infrequency of major complications. A n alternate cutdown site in the u p p e r extremity is t h e cephalic vein in the deltopectoral groove. The basilic vein is located a p p r o x i m a t e l y 1 i n c h above a n d l a t e r a l to t h e m e d i a l epicondyle of the h u m e r u s . A t t h i s ]ocation the basilic vein is in a superficial position. S t e r i l e i n t r a v e n o u s extension t u b i n g or a pediatric feeding tube (3 mm) m a y be used as canhulas. The d i s t a n c e to t h e c e n t r a l veins should be e s t i m a t e d and t u b i n g inserted into the i n t r a t h o r a c i c area. The position of the c a t h e t e r is confirmed by r a d i o g r a p h to insure accurate p l a c e m e n t . The a d v a n t a g e to this method is the lack of major complJcations. 22 D i s a d v a n t a g e s include catheter m i s p l a c e m e n t , i n f e c t i o n , thrombosis, p h l e b i t i s and, f i n a l l y , limitation of m o v e m e n t of t h e arm.S42
External Jugular. Use of t h e external j u g u l a r vein will not be discussed as it is u n r e l i a b l e for catheterization of the superior v e n a cava, principally due to the 90 ° a n g l e at which it e n t e r s the s u b c l a v i a n vein. 22 This angle u s u a l l y will not favor the catheter p a s s i n g t h i s j u n c t i o n or cause its p a s s i n g p e r i p h e r a l l y r a t h e r than centrally. Internal Jugular Cannulation. The internal j u g u l a r vein is our p r e f e r r e d site for g a i n i n g access to the c e n t r a l veins in adults and children. Knowledge of t h e a n a t o m y is e s s e n t i a l . First of all, the c r i t i c a l l a n d m a r k s must be located. The s t e r n o c l e i d o mastoid (SCM) m u s c l e is l o c a t e d in the neck by h a v i n g t h e p a t i e n t turn his head to the opposite side and palpating the muscle belly as it goes to its insertion on the s t e r n u m and clavicle. This muscle forms a t r i a n g l e just superior to the clavicle. The borders of the t r i a n g l e are formed by the clavicle inferiorly and the c l a v i c u l a r and sternal portions of the SCM t h a t join to form the apex of the t r i a n g l e SUperiorly. This is the first l a n d m a r k to i d e n t i f y b e f o r e a t t e m p t i n g t h e cannalation. Secondly, t h e c a r o t i d artery m u s t be p a l p a t e d to avoid its inadvertent puncture. The i n t e r n a l j u g u l a r vein e n t e r s "~P
6:8 (Aug) 1977
CI
5re. r n ocJe.id omastoid i / muscl~
~i
~)internal '] X / / . :
jugular
ein
I n n o n q i n a ~ v,z.i,'~
~-----J.
) Fig 1.--Diagram showing relationship of external anatomical landmarks to underlying internal jugular vein (a). Triangle drawn over clavicle and sternal and clavicular portions of sternocleidomastoid muscle is centered over interna[ jugular vein (b). Fig 2.--Needle is aligned 30 ° posterior to a coronal plane and directed inferiorly to puncture internal jugular vein (a). Detail of securing catheter with a suture near skin ~uncture site (b).
(31
3o ° ....-
.......
.:~i~_-~. ~ ---~L~!;~-~-.~ , ....~:~...... ~-.~?~.. j :<<....... ~., L/
b Fig. 2a. Daily P, et al (reproduced with permission)? 4
t h e c a r o t i d s h e a t h d o r s a l to t h e i n t e r n a l c a r o t i d , ~ t e r y after emerging from t h e base of the skull. It assumes a position l a t e r a l and, finally, a n t e r o l a t e r a l l y to the common caret-
id a r t e r y u n d e r t h e S C M b e f o r e r e a c h i n g t h e clavicle. The i n t e r n a l j u g u l a r r u n s 2 to 3 cm below the s k i n a n d b e t w e e n the two h e a d s of the SCM in t h e s u p e r i o r a s p e c t of the 360/29
Internal
,branch of eidomuscle
External
Clavicul~ of stern( mastoid jugular Clavicle
Subclavian Cannulation. The sub~ c l a v i a n vein has had great popular. ity as a site of access to the superior vena cava for m e a s u r e m e n t of cen. t r a l venous pressure.
Fig. 2b. Needle insertion for internal jugular cannulation.
Infraclavicular subclavian {ternal branch of ;ternocleidonastoid muscle
Clavicular bran of sternocleido mastoid musch
nternal jugular /ein
Site of needle entry for infraclavicular subclavian
Clavicle
Fig. 3. Needle insertion for subclavian cannulation. t r i a n g l e . H o w e v e r , by t h e t i m e it reaches the clavicle, it is located deep to the m e d i a l aspect of the c l a v i c u l a r head of the SCM. Upon reaching the c l a v i c u l a r level, it joins with the subc l a v i a n v e i n to f o r m t h e r i g h t b r a c h i o c e p h a l i c v e i n ? " , 2~ C a n n u l a tion in t h e r i g h t side of the neck is a t t e m p t e d i n i t i a l l y as this side has the following advantages: the r i g h t i n t e r n a l j u g u l a r vein forms almost a s t r a i g h t l i n e to t h e s u p e r i o r v e n a cava, the dome of the pleura is lower on the r i g h t side h e l p i n g to avoid p l e u r a l puncture; .the i n t e r n a l jugul a r vein on the r i g h t side is slightly l a r g e r t h a n the one on the left; and finally, the thoracic duct is located on t h e l e f t s i d e a n d t h e o r e t i c a l l y could be i n j u r e d (as h a s b e e n rep o r t e d in s u b c l a v i a n cannulations).l.9,23-2~, 3o/361
e m e r g e n c y d e p a r t m e n t is re~uscit~, t i o n of t h e c r i t i c a l l y ill infant ~r child. E s t a b l i s h i n g a n intraveno~ line c a n be m o s t difficult and ~e often m u s t resort to cutdown in the leg. S u b c l a v i a n cannulation in erner, g e n c y s i t u a t i o n s is d a n g e r o u s i~ c h i l d r e n u n d e r age two and probably should be avoided. 2° However, a re, cent r e p o r t by Prince 2G describes the use of i n t e r n a l j u g u l a r catheteriza~ tion a n d the a d v a n t a g e s of this teeh, n i q u e in i n f a n t s a n d c h i l d r e n . In those c h i l d r e n who r e q u i r e central v e n o u s p r e s s u r e m o n i t o r i n g , th:e i n t e r n a l j u g u l a r approach m a y be a helpful a l t e r n a t i v e method to venous cutdown.
The n e e d l e is i n s e r t e d n e a r t h e a p e x of t h e t r i a n g l e a n d d i r e c t e d p a r a l l e l to the midline at a 30 ° angle with the p a t i e n t supine (Figure 2). It is u s u a l l y most convenient to rotate the head 30 ° to 45 ° toward the cont r a l a t e r a l side. Local a n e s t h e s i a is used if the p a t i e n t is conscious and t i m e p e r m i t s . S e v e r a l m i l l i l i t e r s of saline are helpful to expel a n y plugs of tissue t h a t m a y e n t e r the needle after it passes t h r o u g h the skin. The needle is directed slightly l a t e r a l to the s a g i t t a l plane• D a r k venous blood will u s u a l l y be a s p i r a t e d at a depth of 2 to 3 cm. After a s p i r a t i n g blood, the protocol for cannulation, listed separately, should be followed. A b r i e f m e n t i o n of the special circ u m s t a n c e s in y o u n g children and inf a n t s s h o u l d be m a d e . One of t h e m o s t t e r r i f y i n g m o m e n t s in t h e
We have used this method of can, n u l a t i o n in t h r e e circumstances: 1) f a i l u r e t o c a n n u l a t e t h e interna} j u g u l a r v e i n on t h e s a m e side; 22 a n a t o m i c or o t h e r contraindication~ (old surgery, etc.) to i n t e r n a l jugula~ c a n n u l a t i o n ; and finally, 3) all case~ of c a r d i o r e s p i r a t o r y arrest. The sub~ c l a v i a n route is preferred in a r r e ~ p a t i e n t s b e c a u s e of the speed wit~ which t h e vein can be cannulated. Furi thermore, endotracheal intuba~ and subclavian catheterization~ be done s i m u l t a n e o u s l y . O b v i o u s ~ use of the i n t e r n a l j u g u l a r approa~ would prohibit s i m u l t a n e o u s i n t u ~ tion. However, e x t e r n a l cardiac com~ Pt~ession a n d v e n t i l a t i o n m u s t ~ ooped for about five to ten secon~ d u r i n g t h e c a n n u l a t i o n attempt. T h e r e a r e two a n a t o m i c a l : ~ p r o a c h e s for s u b c l a v i a n vein e ~ n u l i z a t i o n - - i n f r a c l a v i c u l a r an~ s u p r a c l a v i c u l a r . We have used th~ i n f r a c l a v i c u l a r approach most ofte~ A g r e a t deal of adverse publicity h ~ developed because of the r a t h e r h!.~ incidence of p n e u m o t h o r a x with th~ approach. TM As a result, the i n t e r n ~ j u g u l a r approach has been used mor~__ f r e q u e n t l y with its r e l a t i v e l y l o w ~ c i d e n c e of p n e u m o t h o r a x . 19,22,2~ ~ The s u b c l a v i a n vein (Figure 3), 3 - ~ cm long and 1 to 2 cm in diameter, a c o n t i n u a t i o n of the a x i l l a r v and extends from the outer m a r g i ~ the first rib to the medial border~the scalenus a n t e r i o r where it u n i ~ . 6:8 (Aug) 1977 J ~
f
Table 3 A N A T O M I C STRUCTURES THAT CAN BE INJURED BY SUBCLAVIAN C A N N U L A T I O N i
structure Subclavian artery
Anatomic Relation to Subclavian Vein (SV)
Error in Procedure
Injury
Posterior and slightly superior, separated by scalenus a n t e r i o r - - 10-15 mm in the adult, 5-8 mm in children.
Insertion too deep or laterally
Hemorrhage, hematoma & possible hemothorax
13rachial plexus
Posterior to and separated from SV by the scalenus anterior and subclavian artery (20 mm)
Same as w i t h subclavian artery
Possible motor sensory deficits of hand, arm or shoulder
parietal pleura
Contact w i t h p o s t e r i o r i n f e r i o r side of the SV, medial to the attachment of the anterior scalene muscle to the first rib
Needle p e n e t r a t e s beneath or t h r o u g h both walls of the SV
Pneumothorax
Phrenic nerve
Same as above
Placement of needle above or behind the vein or by penetration of both its walls
Paralysis of the ipsilateral hemi-diaphragm
Thoracic duct
Cross the s c a l e n u s a n t e r i o r and enter the superior margin of the SV near the internal jugular junction
Same as above
Soft t i s s u e l y m p h edema or chylothorax on left
Vagus nerve
Courses behind the internal jugular vein
Too long a n e e d l e inserted too deeply
Hoarseness
with the i n t e r n a l j u g u l a r v e i n to form the bracheocephalic vein. The clavicle and subclavius lie in front of it. Behind and above is the subclavian a r t e r y s e p a r a t e d by t h e scalenus a n t e r i o r m u s c l e . Below, it -rests in a shallow groove on the first rib and upon the pleura. 2s Obviously, there are p o t e n t i a l d a n g e r s i n the ~Wructures s u r r o u n d i n g the subcia~vvanvein ~.~ ITable 3~. After the s k i n is p r e p p e d a n d -6raped in a s t e r i l e f a s h i o n , local anesthesia is used to raise a wheal. =The point of insertion should be lojust l a t e r a l and inferior to the :junction of the middle a n d m e d i a l Ahirds of the clavicle. There are sev~t different ways of i n s e r t i n g the =v.eedle ~7 ~s 29 ao We prefer directing the needle toward the superior aspect of the s u p r a s t e r n a l notch after having advanced the tip of the needle ~ t beneath the inferior aspect of the ~aviele. The most i m p o r t a n t part of the whole procedure comes at this Point and the failure to observe this crucial point is one reason for serious "ff~plications. The syringe_ and neemust be held parallel to the pai r ' s back. The needle is then adVanced slowly with negative pressure ~v-er the f i r s t r i b a n d b e h i n d the ~=I~vicle, ~ at w h i c h t i m e t h e v e i n ~id be entered. Free flow of blood ~uld be n o t e d and t h e protocol ~ )
6:8 (Aug) 1977
should be followed to complete the procedure. Supraclavicular Cannulation (Tables 4 and 5). A n o t h e r a l t e r n a t e approach to c e n t r a l venous c a n n u l a t i o n is the s u p r a c l a v i c u l a r method. This method was developed p r i m a r i l y to avoid the major complications of the i n f r a c l a v i c u l a r method - - especially pneumothorax. ~1 The i m p o r t a n t l a n d m a r k fbr this method is the j u n c t i o n of the lateral border of the clavicular head of the sternocleidomastoid muscle and superior aspect of the clavicle. This can be visualized and easily palpated "in most patients. Since the o r i g i n a l description of this t e c h n i q u e by Yoffa, 31 there have b e e n s e v e r a l m o d i f i c a t i o f f s suggested, a2,a3 The " j u n c t i o n a l " stick has several theoretical advantages. In contrast to catheterization of the s u b c l a v i a n vein, the j u n c t i o n of the s u b c l a v i a n and the i n t e r n a l j u g u l a r v e i n is used. This has two a d v a n tages, a larger target and direction of the needle toward the m e d i a s t i n u m t h e r e b y a v o i d i n g the p l e u r a if the vein is missed. The skin is entered at the j u n c t i o n of the l a t e r a l a s s e t of the clawcular h e a d of t h e SC~I m u s c l e a n d the superior aspect of the clavicle. The needle is directed in the following
m a n n e r : s l i g h t l y p o s t e r i o r at a 5 ° angle from the coronal plane, at a 50 ° angle from the sagittal plane, and at a 40 ° a n g l e from t h e t r a n s v e r s e planeY 2 After blood is aspirated, the protocol is fbllowed IFigure 4/.
C O M P L I C A T I O N S (Tables 6 and 7) T h r e e c o m p l i c a t i o n s need to be mentioned: pneumothorax, arterial puncture, and air emholus. P n e u m o t h o r a x has occurred with some f r e q u e n c y w i t h the infi'aclavicular approach, especially under e m e r g e n c y circumstances, ls,21 Furt h e r m o r e , t h e f r e q u e n c y of p n e u mothorax is directly proportional to the i n e x p e r i e n c e of the p h y s i c i a n performing the procedure. Use of the i n t e r n a l j u g u l a r a p p r o a c h has resulted in a lower incidence of pneumothorax. To avoid a p n e u m o t h o r a x u s i n g the i n f r a c l a v i c u l a r approach, the syringe and needle m u s t be kept level with the ground and the needle m u s t h u g the u n d e r s u r f a c e of the clavicle. A r t e r i a l punctures occur in both the i n t e r n a l j u g u l a r and subclavian approaches, involving the subclavian and carotid arteries.17,19, 2a With the i n t e r n a l j u g u l a r approach, the carotid artery can be avoided by palpation before and d u r i n g i n s e r t i o n of the needle. The subclavian artery will be 362/31
Table 4 ADVANTAGES AND DISADVANTAGES OF TECHNIQUES Technique Basilic (peripheral)
Internal jugular
Advantages
Disadvantages
Low incidence of major complications
Greater incidence of minor complications of infection, p h l e b i t i s and thrombosis.
Allows large quantities of fluid to be given rapidly
More difficult to place catheter in correct position for central venous pressure monitoring
3. Prep the right neck and anteriQr'! chest wall almost to the nipple i
" B l i n d " procedure
5. Sterile technique is mandatory and it is most helpful to have a ready-made sterile CVP kit.
Good e x t e r n a l marks
land-
Lesser risk of pneumothorax than subclavian puncture
Has a slightly higher incidence of failures than subclavian
Bleeding can be recognized and controlled
More difficult and inconvenient to secure
Large rapid flow Useful a l t e r n a t i v e approach to cutdown in children under the age of two Good e x t e r n a l marks
land-
H i g h e r i n c i d e n c e of complications especially in hypovolemic shock
Large rapid flow
"Blind" procedure
Most practical method of inserting a central line in cardiorespiratory arrest
Should not be attempted in children underage two
Large rapid flow
" B l i n d " procedure
Good landmarks Less risk of pneumothorax than infraclavicular avoided if t h e p h y s i c i a n obeys t h e s a m e "safety rules" mentioned above with the p n e u m o t h o r a x . In t h e a d u l t t h e r e is 1 to 1.5 cm distance b e t w e e n vein and artery. U s u a l l y it will t a k e a deep stick to p u n c t u r e the a r t e r y . This is not true in infants and child r e n w h e r e t h a t d i s t a n c e is m u c h smaller. A i r embolus can be avoided bylS, is 1) p l a c i n g the p a t i e n t in the Trend e l e n b e r g p o s i t i o n to d i s t e n d t h e
4. Drape the area.
I
6. Disassemble the intracath and place needle on a 5 cc syringe, 7. Select site for cannulation. 8. Insert needle and maintain negative pressure until the free flow of blood is established. Immobilize the needle and remove the syringe covering the open end of the needle with a gloved thumb£ or finger. Some authors2°, 2~ use" an initial probe with a 21 gauge~ needle to locate the internal jug.t ular.
Carotid artery e a s i l y identified
32/363
2. Have patient stripped to the:: waist and in Trendelenburg P0si,~ tion to distend the veins and Pre,, vent air embolism, i
Hinders free movement of arms
Almost a straight course to the superior vena cava on the right side
Supraclavicular functional)
1. Legitimate indication; no C0n,! traindications.
Performed under direct visualization of vein
Malposition of catheter is rare
Infraclavicular subclavian
Table 5 PROTOCOL FOR CATHETERIZATION
veins; 2) k e e p i n g a finger or t h u m b o v e r t h e h u b of t h e n e e d l e before t h r e a d i n g the catheter; 3) h a v i n g the p a t i e n t stop b r e a t h i n g and preferably p e r f o r m i n g V a l s a l v a ' s m a n e u v e r d u r i n g t h i s c r i t i c a l period, a n d finally, 4) ensure t h a t the i n t r a v e n o u s line fits s n u g l y into the c a t h e t e r to a v o i d d i s c o n n e c t i o n of t h e t u b i n g from the catheter_ This can be done by s p l i n t i n g the i n t r a v e n o u s t u b i n g to the c a t h e t e r w i t h a tongue blade and tape.
9. Thread 8" catheter through t ~ , needle. If any difficulty is encoun~ tered, try rotating catheter• If stili~ having difficulty, try rotating thiner. needle and then attempt t h r e a d i % 10. Do not force the c a t h e t e ~
~L
11. Never withdraw the cathete~ through the needle! J 12. After catheter is in place andJ stylet is withdrawn, attach largE syringe to catheter and aspirate~ to confirm position.
13. Withdraw the needle so thati it is completely visible. Use safety clip to immobilize needle against ~ catheter. 14. Attach the intravenous tubing and CVP manometer• 15. Secure catheter in place with suture. 16. Antibiotic ointment, 4 x 4's, Benzoin and tape. 17. Chest radiograph to assess location of catheter. 18. Check the fluid level in the manometer to insure that it fluctuates with respiration.
6:8 (Aug)1977 J ~ :
f
I n t e r p r e t a t i o n of CVP may be difficult_ It is i m p o r t a n t to use serial CVP m e a s u r e m e n t s r a t h e r t h a n one isolated reading. Knowledge of the p a t i e n t ' s clinical condition, i n c l u d i n g m e a s u r e m e n t s of blood p r e s s u r e , pulse rate, u r i n e output, etc., as well as his cardiac status, is essential in o r d e r to i n t e r p r e t c e n t r a l v e n o u s pressure accurately. Finally, the use of a fluid challenge is helpful in accurately assessing the patient's volume status. 4s
supraclavicula subclavian
site of needle entry for supr~ clavicular subclavian
Fig. 4.
CENTRAL VENOUS PRESSURE
Measurement. T h r e e factors are necessary to assure accurate central venous pressure m e a s u r e m e n t . First, the patient m u s t be supine. Second, the catheter must be p a t e n t and accurately located in the central veins. This can be d e t e r m i n e d by r a d i o .graphic localization o f the c a t h e t e r 4ip,4°,41 fluctuation of the column of fluid during respiration, and aspiration of blood after the c a t h e t e r is placed and before the m a n o m e t e r is ~nnected. Third, a baseline e x t e r n a l zero point should be established by marking a spot on the p a t i e n t so t h a t future r e a d i n g s can be t a k e n from ~he same point.
to c e n t r a l venous pressure is as follows: n o r m a l , 4~-45 5 to 12 cm H_~O; low, below 5 cm I-hO; high, above 12 to 15 cm I ~ O . All readings are t a k e n at end expiration.
The concept of fluid challenge and its t e c h n i q u e needs futher discussion due to its importance in the interpret a t i o n of c e n t r a l venous pressure. In order to assess either volume deficits or p u m p failure, aliquots of between 100 a n d 200 ml of crystalloid fluid are a d m i n i s t e r e d i n a s y s t e m a t i c m a n n e r . A reference pressure value is e s t a b l i s h e d d u r i n g a t e n - m i n u t e period of observation. The aliquot of fluid is r u n i n over the n e x t tenm i n u t e p e r i o d . If t h e C V P is in-
Table 6 COMPLICATIONS (GENERAL) Both peripheral and central:
L
There has been a great deal of debate concerning the location of the :zero point. A n u m b e r of a n a t o m i c a l sites have been recommended.4,23, 42 -tnpractice, we have used 40% to 45% of the anterior-posterior (AP) diameter of the chest, m e a s u r e d a n t e r i o r to posteriorly at the fourth intercostal space to approximate the location of the tricuspid valve. It is i m p o r t a n t to realize t h a t the absolute zero level is less i m p o r t a n t t h a n following serial measurements t a k e n at the same location a n d i n t h e s a m e m a n n e r . Changes in CVP with' serial measurements are an i m p o r t a n t diagnostic aid in the emergency d e p a r t m e n t . The common causes for incorrect central venous pressure r e a d i n g s are listed (Table 8).
Interpretation.
A rough g u i d e l i n e
6:8 (Aug)1977
1. Aberrant placement a. erroneous pressure readings b. perforation of veins c. arrhythmias d. perforation of myocardium with resultant pericardial tamponade e. hydromediastinum and hydrothorax
Solution These can be avoided by x-ray film confirmation after placement, anchoring the catheter in place, observing fluctuation of manometer level and the aspiration of free flowing blood after i n s e r t i o n of the catheter. 2. Catheter emboli: occurs usually under two circumstances: a. attempting to withdraw catheter through the needle b. catheter is cut while removing a suture
Solution Never w i t h d r a w catheter t h r o u g h the needle, withdraw catheter and needle as a unit. 3. Infections
Solution a. sterile technique b. rigid attention to site care c. percutaneous rather than cutdown technique d. removal as soon as possible 4. Thrombosis and thrombophlebitis
Solution a. percutaneous cannulation of large central veins with : ~ a p i d flow rather than peripheral vein b. avoid catheterization of leg veins - - femoral, saphenous, etc.
364/33
Table 7 S P E C I F I C C O M P L I C A T I O N S OF SUBCLAVIAN AND INTERNAL J U G U L A R M E T H O D S 7, 17-19,2g, 37-39
Table 8 C O M M O N C A U S E S FOR INCORRECT CENTRAL VENOUS PRESSURE READINGS 5
1. Pneumothorax
1. Patient has not been returned to level position from Trendelenburg after catheter inserted.
2. Arterial puncture
2. Incorrect zero point.
3. Bleeding from catheter site
3. Knot in the catheter or catheter is pinched by the protective "wing.,,
4. Air embolus
4. Changes in intrathoracic pressure (Valsalva, patient on respirator, tension pneumothorax).
5. Brachial plexus injury 6. Internal mammary - - subclavian only
injury
7. Thoracic duct injury 8. Osteomyelitis of clavicle - subclavian only
5. Catheter tip obstruction either by clot formation or occlusion against vessel wall. 6. Incorrect location: a. peripheral location b. right ventricle 7. Fluids running into manometer during measurement.
9. Phrenic injury 10. Vagus injury 11. Horner's syndrome
c r e a s e d b y m o r e t h a n 5 c m of w a t e r d u r i n g t h i s i n t e r v a l , t h e i n f u s i o n is d i s c o n t i n u e d . I f t h e C V P does n o t exceed its c o n t r o l v a l u e b y m o r e t h a n 2 c m I-leO a t t h e e n d o f t e n m i n u t e s , or if it d e c l i n e s to w i t h i n t h a t r a n g e o v e r a s e c o n d t e n - m i n u t e w a i t i n g period, t h e s e c o n d a l i q u o t is a d m i n i s t e r e d o v e r t e n m i n u t e s . T h i s process is repeated using two ten-minute seq u e n c e s , o n e for f l u i d a d m i n i s t r a t i o n a n d t h e s e c o n d f o r o b s e r v a t i o n of C V P . A p r o g r e s s i v e r i s e i n C V P exc e e d i n g 5 c m of w a t e r c o n s t i t u t e s indication of a limited cardiac competence_43, 44 W i t h so m a n y v a r i a b l e s p r e s e n t , it is c r i t i c a l to u s e g r e a t c a r e i n d r a w ing conclusions from CVP readings. Overestimating the information g a i n e d f r o m a C V P r e a d i n g is a r e a son central venous pressure has been a c o n t r o v e r s i a l topic. It is e s s e n t i a l to k n o w its l i m i t a t i o n s . B y u s i n g t h e f l u i d c h a l l e n g e t e c h n i q u e a n d correlating the measurements with the patient's cardiac status, the central v e n o u s p r e s s u r e is a u s e f u l aid to t h e emergency physician. REFERENCES 1. Huberty J, Schwartz R, Emich J: Central venous pressure monitoring. Obstet Gynecol 30:842-850, 1967. 2. Aubaniac R: Une nouvelle vole d'injection au de poncture veineuse: la voieclaviculaire. Sere Hop Paris 28:3445, 1952. 34/365
3. Wilson J, Grow J, Demong C, et al: Central venous pressure in optimal blood volume maintenance. Arch Surg 85:563578, 1962. 4. Guyton A, J o n e s C: C e n t r a l venous pressure: physiological significance and clinical implications. A m Heart J 86:431437, 1973. 5. Central Venous pressure monitoring, editorial. Br Med J 3:246-247, 1971. 6. Borow M, Aquilizan L, Krausz A, et al: The use of central venous pressure as an accurate guide for body fluid replacement. Surg Gynecol Obstet 120:545-552, 1965. 7. Wilson J, Owens J: Pitfalls in monit o r i n g c e n t r a l v e n o u s p r e s s u r e . Hosp Med 6:86-93, 1970. 8. L o n g e r b e a m , et al: C e n t r a l v e n o u s p r e s s u r e m o n i t o r i n g . A m J Surg 110: 220-229, 1965. 9. Brouchow I, Mac V a u g h H: C e n t r a l venous p r e s s u r e m o n i t o r i n g . Rev Surg 24:163-167, 1967. 10. Riordan J, Walters G, McLay W: The significance of c e n t r a l venous p r e s s u r e a n d c a r d i a c o u t p u t m e a s u r e m e n t s in shock. Postgrad Med J 45:506-513, 1969. 11. MacLean and Duff: The use of central venous pressure as a guide to volume replacement in shock. Dis Chest 48:199-205, 1965. 12. Small K, Conseiller C, Viars P: Central venous pressure and pulmo.nary wedge p r e s s u r e . Arch Surg 111:11221125, 1976. 13. DeLaurentis D, Hayes M, Matsumoto T: Does c e n t r a l venous pressure accurately reflect hemodynamic and fluid volume p a t t e r n s in the critical surgical patient. A m J Surg, 126:415-418, 1973. 14. Toussaint GP, Burgess J, Hampson L: Central venous pressure and pulmonary wedge pressure in critical surgical illness. Arch Surg 109:265-269, 1974. 15. Lewis FR: C u r r e n t concepts in car-
diovascular monitoring (trauma rounds). West J Med 122"339-344, 1975. 16. T r u n k e y D, Holcroft J, Carpenter M: Monitoring resuscitation of primates from h e m o r r h a g i c and septic shock. JACEP 5:249-252, 1976. 17. B e r n a r d RW, Stahl W, Chase R: Sul~ clavian vein catheterizations: a prospec. tive study I a n d II. Ann Surg 173:184. 200, 1971. 18. Mitty WF, Nealon T Jr: Complica. tions of subclavian sticks. JACEP 4:2~ 28, 1975. 19. Defalque RJ: Percutaneous catheterization of the i n t e r n a l jugular vein. Anesth Analg 53:116-121, 1974. 20_ Groff DB, A h m e d N: Subclavian vein c a t h e t e r i z a t i o n in the infant. J Pediatr Surg 9:171-174, Apr 1974. 21. T r u n k e y D: Assessment and resusci. r a t i o n of t h e i n j u r e d p a t i e n t (trauma rounds). West J Med 121:153-157, 1974. : 22. J e r n i g a n WR, Gardner W, Mahr 1~I; Use of t h e i n t e r n a l j u g u l a r vein for p l a c e m e n t of c e n t r a l venous catheter. Surg Gynecol Obstet 133:520-524, 197023. V a u g h a n RW, W e y g a n d t GT: Per. c u t a n e o u s c e n t r a l v e n o u s pressure measurement. Anesth Analg 52:709-716~ 1973. 24. Daily P, Griepp R, Shumway N: percutaneous i n t e r n a l jugular vein cannulation. Arch Surg 101:534-536, 1970. 25. McConnell RY, Fox RT: Experience with percutaneous internal jugular i n n o m i n a t e vein catheterization. West J Med 117:1-6, 1972. 26. Prince S, Sullivan RL, Hackel A: per. cutaneous catheterization of the internal j u g u l a r v e i n in i n f a n t s a n d children' Anesthesiology 44:170-174, 1976. 27. B r i n k m a n AJ, Costley DO: Inter'_ nal j u g u l a r v e n a p u n c t u r e . J A M A 223:~ 182-183, 1973.
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~8. Warwich and Williams: Gray's AnatDr~Y,35th British Edition. ~9. Moosman DA: The anatomy of infracl~¢icular subclavian vein catheterization -d its c o m p l i c a t i o n s . Surg Gynecol ~stet 136:71-74, 1973. 30. 1V[ogel R, DeLaurentis D, Rosemond G: The i n f r a c l a v i c u l a r v e n a p u n c t u r e . Arch Surg 95:320-324, 1967. 31. yoffa D: Supraclavicular subclavian venapuncture a n d catheterization. Lancet
2:1972. 32- Garcia JM, Mispireta L, Pinho R: percutaneous supraclavicular superior vena cava cannu]ation. Surg Gynecol Obstet 134:839-841, 1972. 33. James P, Myers R: C e n t r a l venous pressure m o n i t o r i n g . A n n S u r g 175: 693-701, 1972. 34. Greenall M J, Blewitt RW, McMahon MJ: Cardiac tamponade and central ve-
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nous catheters. Br Med J 7:595-597, 1975.
- /~ e ~ ASSOC d I U l l O ~ O - O ' i ~ I V u v ,
35. Oureshi GD, Lilly EL: Complications of CVP c a t h e t e r insertion in cubital vein. J A M A 209:1906, 1969.
41. Thomas, T: Location of c a t h e t e r tip a n d its i m p a c t on central venous pressure. Chest 61:668-673, 1972.
36. Royal H, Shields J, Donati R: Misp l a c e m e n t of c e n t r a l v e n o u s p r e s s u r e catheters and u n i l a t e r a l pulmonary edem a . A r c h Intern Med 135:1502-1505, 1975.
42. Robson MD: Technique for obtaining reproducible central venous pressure. Johns Hopkins Med 122:232-235, 1968.
37. J a m e s P: Clinical use of central venous cannulation. Postgrad Med 55:155160, 1974.
43. D e b u m m e r F, Buhler F: Normal cent r a l v e n o u s p r e s s u r e , s i g n i f i c a n c e of r e f e r e n c e p o i n t and n o r m a l r a n g e . B r Med J 3:148-50, 1969.
38. Borja A: C u r r e n t s t a t u s of i n f r a clavicular s u b c l a v i a n vein catheterization. A n n Thorac Surg 13:615-624, 1972.
44. J a i k a r i a n SMN, Sagay E: N o r m a l central venous pressure. Br J Surg 55:609-612, 1968.
39. Adar R, M e z e s M: F a t a l complicat i o n s of c e n t r a l v e n o u s c a t h e t e r s . Br Med J 3:746, 1971.
45. W e i l MH, S h u b i n H: T h e " V I P " approach to the bedside m a n a g e m e n t of shock. J A M A 297:337-340, 1969.
40. Gilday D, Downs A: The v a l u e of chest r a d i o g r a p h y in the localization of c e n t r a l venous pressure catheters. Can
46. Weil MH, Shubin H, Rosoff L: Fluid r e p l e t i o n in c i r c u l a t o r y shock. J A M A 192:84-90, 1965.
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Central Venous Cannulation and Pressure Monitoring Robert Knopp, MD Robert H. Dailey, MD Fresno, California
Central v e n o u s p r e s s u r e (CVP) v a r i e s d i r e c t l y w i t h c i r c u l a t i n g b l o o d volume and v a s c u l a r tone a n d i n v e r s e l y w i t h right h e a r t c o m p e t e n c y . Indications for c e n t r a l c a n n u l a t i o n i n c l u d e c a r d i o r e s p i r a t o r y arrest. The t w o g e n e r a l a p p r o a c h e s to c a n n u l a t i o n o f c e n t r a l v e i n s are peripheral and central. The p h y s i c i a n ' s skill, patient's b o d y habitus, clinical circumstances, age and t h o r a c i c d e f o r m i t y all i n f l u e n c e the c h o i c e of technique. Three o f the p o s s i b l e c o m p l i c a t i o n s d i s c u s s e d are p n e u m o thorax, a r t e r i a l p u n c t u r e a n d air e m b o l u s . A c c u r a t e m e a s u r e m e n t of CVP d e p e n d s o n the p a t i e n t b e i n g s u p i n e , a p a t e n t and a c c u r a t e l y located c a t h e t e r a n d the e s t a b l i s h m e n t of a b a s e l i n e e x t e r n a l zero point.
Knopp R, Dailey RH: Central venous cannulation and pressure monitoring. 6:358-366, August, 1977. c e n t r a l v e n o u s p r e s s u r e , c a t h e r i z a t i o n .
JACEP
INTRODUCTION In 1931, F o r s s m a n ~ first catheterized the h e a r t and m e a s u r e d central venous pressure. However, it was not until A u b a n i a c 2 described t h e technique of percutaneous s u b c l a v i a n v e n i p u n c t u r e in 1952 and W i l s o n 3 refined this t e c h n i q u e ten years l a t e r that c a n n u l a t i o n of the central veins and m e a s u r e m e n t of central venous pressure were commonly used. Since that time m a n y techniques to simplify the procedure h a v e been described. The purpose of our paper is to r e v i e w cannulation of the central veins and discuss t h e p h y s i o l o g y , u s e s a n d
From the Department of Emergency Medicine, Valley Medical Center, Fresno, California. Address for reprints: Robert Knopp, MD, Valley Medical Center, 445 S. Cedar AvCane, Fresno, California 93702.
J~P
6:8 (Aug) 1977
abuses of c e n t r a l venous pressure. The e m e r g e n c y d e p a r t m e n t and the critically ill or injured p a t i e n t serve as our reference point.
PHYSIOLOGICAL CONSIDERATIONS Venous pressure arises from arterial pressure t r a n s m i t t e d t h r o u g h the cap i l l ar y bed. Cen t r al venous pressure (CVP) refers to the pressure in the large intrathoracic veins. Pressure from the superior v e n a cava or one of its v al v el ess t r i b u t a r i e s is usually w i t h i n 1 ml of r i g h t atrial pressure. 4 As a result, CVP is a m e a s u r e of t h e filling pressure of the r i g h t ventricle. 5 P e r i p h e r a l venous pressure does not correlate w.~h central venous pressure due to e x t e r n a l pressure on the veins, venospasm, and the presence of valves. 6
It is e s s e n t i a l to u n d e r s t a n d t h a t CVP is not a m easu r e of blood volu m e s t a t u s alone. CVP varies directly w i t h c i r c u l a t i n g blood v o l u m e and v a s c u l a r tone and i nve r s e l y w i t h r i g h t h e a r t competency. 1-11 It ma y be useful to t h i n k of these factors as a closed s y s t e m consisting of a pump (the heart) connected to a c o n t a i n e r (vascular capacitance) and fluid t h a t is p u m p e d t h r o u g h the c o n t a i n e r (blood volume) (Figure 1). S i n c e t h e a d v e n t of m e a s u r i n g p u l m o n a r y wedge pressure w i t h the S w a n - G a n z catheter, the accuracy of CV P has been questioned. 12-1s Left a t r i a l p r e s s u r e (LAP) and C V P do not a l w a y s move in pa r a l l e l . However, recent reports 5,14,16 h a v e erap h a s i z e d t h a t in p a t i e n t s w i t h o u t c a r d i o v a s c u l a r or severe p u l m o n a r y disease, CV P and LA P tend to correl a t e closely_ C V P a l w a y s r e f l e c t s r i g h t atrial pressure (RAP) and, in p a t i e n t s w i t h o u t cardiac or pulmon a r y disease, often reflects LAP.~5, ~ Discussions concerning the subtle d i f f er en ces b e t w e e n C V P and L A P should not obscure the fact t h a t CVP is a useful m e a s u r e m e n t . A l t h o u g h not as precise as LAP, in most situations CV P is an adequate volume ind i cat o r w h e n properly done in the a v e r a g e patient. 1~ In the e m e r g e n c y d e p a r t m e n t , m o s t p a t i e n t s c a n be a d e q u a t e l y monitored using CVP.
CENTRAL CANNULATION I n d i c a t i a n s ( T a b l e 1). A r e c e n t
358/27
addition to the indications for central c a n n u l a t i o n is cardiorespiratory atrest. E s t a b l i s h i n g a central line in the arrested p a t i e n t allows intravenous medications to be given close to t h e i r site of action and shortens the time needed to circulate the drugs. In addition, successful c a n n u l a t i o n of the central veins eliminates the need for intracardiac injections, T h e r e are o t h e r i n d i c a t i o n s for c e n t r a l c a t h e t e r i z a t i o n such as hyp e r a l i m e u t a t i o n b u t t h i s is n o t u s u a l l y performed in the emergency d e p a r t m e n t a n d therefore we have excluded it.
Contrairzdications (Table 2). The most i m p o r t a n t is a lack of experience on the p a r t of the p h y s i c i a n . Supervision by a n experienced physician d u r i n g one's first few attempts at c a n n u l a t i o n and a good working knowledge of the a n a t o m y are essential.17,ts
PITFALLS IN INTERPRETATION OF CVP MONITORING k-
CVP reflects the dynamic interrelationship between It is not an index of
cardiac action cardiac output or adequacy
The femoral vein was commonly u s e d in t h e p a s t . It lies in t h e f e m o r a l t r i a n g l e m e d i a l to t h e femoral artery j u s t below the inguihal ligament. This vessel would app e a r w e l l s u i t e d for c a n n u l a t i o n since it is easily located and has no vital s t r u c t u r e s s u r r o u n d i n g it (except for the femoral artery). It can be c a n n u l a t e d by either cutdown or percutaneously. However, frequent sepsis and thromboembolism restrict its r o u t i n e use.~,e, ? R e l a t i v e leg iram o b i l i z a t i o n is r e q u i r e d a f t e r a femoral c u t d o w n and this t e n d s to increase the chance of thrombosis. T h e r e f o r e , w h e n b e t t e r s i t e s are available, we feel that this approach should not be used. 28/359
blood volume blood volume
It indicates only how efficiently the right ventricle is clearing the venous return at the time of measurement Recognition of CVP as a function of these three major clinical variables helps to obviate the numerous pitfalls in interpretation discussed in the text. ~,-
II;ll
z . ' ~ ~. z )
~
The pitfalls and limitations of CVp monitoring can be largely circurn" vented by two refinements:
~
Vascular tone
Cardiac action
Techniques. There are two general approaches to c a n n u l a t i o n of the central veins - - peripheral and central. Each has a d v a n t a g e s and disadvantages; physicians should choose the approach that, in their hands, is the safest and technically most successful. A n e m e r g e n c y p h y s i c i a n m u s t have facility with more t h a n one approach. Body h a b i t u s , clinical circumstances (eg, cardiorespiratory arrest), age (eg, children versus adults), and thoracic deformity all influence the choice of appro ach. ',9,2o Peripheral approaches include femoral vein, basilic vein and the cephalic vein in the deltopectoral groove.
vascular tone circulatory adequacy
Blood volume
1 Observeserial CVP measurements with particular attention to CVp response following any therapeu. tic trial 2 Incorporate simultaneous assessment of cardiac output adequacy with CVP measurements. This affords very precise analysis of exist. ing cardiocirculatory dynamics
Fig. 1. Wilson and Owens (reproduced with permission). 7
Table 1 I N D I C A T I O N S FOR CENTRAL VENOUS C A N N U L A T I O Nlg,22,2s,z1,33
Table 2 CONTRAINDICATIONS17J 8 i . C o m b a t i v e patients
1. S h o c k
2. Lack of real i n d i c a t i o n
2. C a r d i o r e s p i r a t o r y arrest
3. D i s t o r t e d l a n d m a r k s
3. Lack of a d e q u a t e p e r i p h e r a l v e i n s (old c u t d o w n s , n e e d l e tracks, obesity, etc.)
4. Patients w i t h c o a g u l a t i o n d i s o r d e r s (relative)
4. Severe b u r n s 5. C e n t r a l monitoring
venous
5. I n e x p e r i e n c e a n d / o r lack of k n o w l e d g e of the a n a t o m y
pressure
6. T r a n s v e n o u s p a c e m a k e r 7. Any u n s t a b l e c a r d i o c i r c u l a to ry state
The,,rbasilic vein in the a n t i c u b i t a l fossa is our preferred approach for peripheral c a n n u l a t i o n . However, p e r c u t a n e o u s c a n n u l a t i o n h e r e is often impossible due t o v e n o u s collapse, n e c e s s i t a t i n g a cutdown at this site_ Some physicians prefer this method to central (subclavian or i n t e r n a l j u g u l a r ) c a n n u l a t i o n in the p a t i e n t w i t h h y p o v o l e m i c shock. The role of percutaneous s u b c l a v i a n or intern a l j u g u l a r in emergency situations has been challenged by some. 1s,21 They
s t a t e t h a t t h e s e p r o c e d u r e s may p r o d u c e a d d i t i o n a l complications s u c h as p n e u m o t h o r a x a n d are u n r e l i a b l e in the volume depleted patient. S u b c l a v i a n or i n t e r n a l jugular catheterization, they maintain, should be reserved for pa" tients h a v i n g pure cardiac emergen'. cies and full vessels or for patients in whom elective placement of a central line is indicated. These procedures are blind, i n v a s i v e and potentially dangerous. In t r a u m a t i c shock we believe t h a t the subclavian and espe': c i a l l y t h e i n t e r n a l j u g u l a r aF proaches are an a l t e r n a t i v e to cut" down at the basilic vein for cannulat" : ing the c e n t r a l veins. The primary a d v a n t a g e of the basilic vein cat6:8 ( A u g ) 1 9 7 7 ~ " ~ 2
d0w~ are the large volumes of fluid that can be given to a p a t i e n t w h e n iotravenous extension t u b i n g is used for the cutdown and the r e l a t i v e infrequency of major complications. A n alternate cutdown site in the u p p e r extremity is t h e cephalic vein in the deltopectoral groove. The basilic vein is located a p p r o x i m a t e l y 1 i n c h above a n d l a t e r a l to t h e m e d i a l epicondyle of the h u m e r u s . A t t h i s ]ocation the basilic vein is in a superficial position. S t e r i l e i n t r a v e n o u s extension t u b i n g or a pediatric feeding tube (3 mm) m a y be used as canhulas. The d i s t a n c e to t h e c e n t r a l veins should be e s t i m a t e d and t u b i n g inserted into the i n t r a t h o r a c i c area. The position of the c a t h e t e r is confirmed by r a d i o g r a p h to insure accurate p l a c e m e n t . The a d v a n t a g e to this method is the lack of major complJcations. 22 D i s a d v a n t a g e s include catheter m i s p l a c e m e n t , i n f e c t i o n , thrombosis, p h l e b i t i s and, f i n a l l y , limitation of m o v e m e n t of t h e arm.S42
External Jugular. Use of t h e external j u g u l a r vein will not be discussed as it is u n r e l i a b l e for catheterization of the superior v e n a cava, principally due to the 90 ° a n g l e at which it e n t e r s the s u b c l a v i a n vein. 22 This angle u s u a l l y will not favor the catheter p a s s i n g t h i s j u n c t i o n or cause its p a s s i n g p e r i p h e r a l l y r a t h e r than centrally. Internal Jugular Cannulation. The internal j u g u l a r vein is our p r e f e r r e d site for g a i n i n g access to the c e n t r a l veins in adults and children. Knowledge of t h e a n a t o m y is e s s e n t i a l . First of all, the c r i t i c a l l a n d m a r k s must be located. The s t e r n o c l e i d o mastoid (SCM) m u s c l e is l o c a t e d in the neck by h a v i n g t h e p a t i e n t turn his head to the opposite side and palpating the muscle belly as it goes to its insertion on the s t e r n u m and clavicle. This muscle forms a t r i a n g l e just superior to the clavicle. The borders of the t r i a n g l e are formed by the clavicle inferiorly and the c l a v i c u l a r and sternal portions of the SCM t h a t join to form the apex of the t r i a n g l e SUperiorly. This is the first l a n d m a r k to i d e n t i f y b e f o r e a t t e m p t i n g t h e cannalation. Secondly, t h e c a r o t i d artery m u s t be p a l p a t e d to avoid its inadvertent puncture. The i n t e r n a l j u g u l a r vein e n t e r s "~P
6:8 (Aug) 1977
CI
5re. r n ocJe.id omastoid i / muscl~
~i
~)internal '] X / / . :
jugular
ein
I n n o n q i n a ~ v,z.i,'~
~-----J.
) Fig 1.--Diagram showing relationship of external anatomical landmarks to underlying internal jugular vein (a). Triangle drawn over clavicle and sternal and clavicular portions of sternocleidomastoid muscle is centered over interna[ jugular vein (b). Fig 2.--Needle is aligned 30 ° posterior to a coronal plane and directed inferiorly to puncture internal jugular vein (a). Detail of securing catheter with a suture near skin ~uncture site (b).
(31
3o ° ....-
.......
.:~i~_-~. ~ ---~L~!;~-~-.~ , ....~:~...... ~-.~?~.. j :<<....... ~., L/
b Fig. 2a. Daily P, et al (reproduced with permission)? 4
t h e c a r o t i d s h e a t h d o r s a l to t h e i n t e r n a l c a r o t i d , ~ t e r y after emerging from t h e base of the skull. It assumes a position l a t e r a l and, finally, a n t e r o l a t e r a l l y to the common caret-
id a r t e r y u n d e r t h e S C M b e f o r e r e a c h i n g t h e clavicle. The i n t e r n a l j u g u l a r r u n s 2 to 3 cm below the s k i n a n d b e t w e e n the two h e a d s of the SCM in t h e s u p e r i o r a s p e c t of the 360/29
Internal
,branch of eidomuscle
External
Clavicul~ of stern( mastoid jugular Clavicle
Subclavian Cannulation. The sub~ c l a v i a n vein has had great popular. ity as a site of access to the superior vena cava for m e a s u r e m e n t of cen. t r a l venous pressure.
Fig. 2b. Needle insertion for internal jugular cannulation.
Infraclavicular subclavian {ternal branch of ;ternocleidonastoid muscle
Clavicular bran of sternocleido mastoid musch
nternal jugular /ein
Site of needle entry for infraclavicular subclavian
Clavicle
Fig. 3. Needle insertion for subclavian cannulation. t r i a n g l e . H o w e v e r , by t h e t i m e it reaches the clavicle, it is located deep to the m e d i a l aspect of the c l a v i c u l a r head of the SCM. Upon reaching the c l a v i c u l a r level, it joins with the subc l a v i a n v e i n to f o r m t h e r i g h t b r a c h i o c e p h a l i c v e i n ? " , 2~ C a n n u l a tion in t h e r i g h t side of the neck is a t t e m p t e d i n i t i a l l y as this side has the following advantages: the r i g h t i n t e r n a l j u g u l a r vein forms almost a s t r a i g h t l i n e to t h e s u p e r i o r v e n a cava, the dome of the pleura is lower on the r i g h t side h e l p i n g to avoid p l e u r a l puncture; .the i n t e r n a l jugul a r vein on the r i g h t side is slightly l a r g e r t h a n the one on the left; and finally, the thoracic duct is located on t h e l e f t s i d e a n d t h e o r e t i c a l l y could be i n j u r e d (as h a s b e e n rep o r t e d in s u b c l a v i a n cannulations).l.9,23-2~, 3o/361
e m e r g e n c y d e p a r t m e n t is re~uscit~, t i o n of t h e c r i t i c a l l y ill infant ~r child. E s t a b l i s h i n g a n intraveno~ line c a n be m o s t difficult and ~e often m u s t resort to cutdown in the leg. S u b c l a v i a n cannulation in erner, g e n c y s i t u a t i o n s is d a n g e r o u s i~ c h i l d r e n u n d e r age two and probably should be avoided. 2° However, a re, cent r e p o r t by Prince 2G describes the use of i n t e r n a l j u g u l a r catheteriza~ tion a n d the a d v a n t a g e s of this teeh, n i q u e in i n f a n t s a n d c h i l d r e n . In those c h i l d r e n who r e q u i r e central v e n o u s p r e s s u r e m o n i t o r i n g , th:e i n t e r n a l j u g u l a r approach m a y be a helpful a l t e r n a t i v e method to venous cutdown.
The n e e d l e is i n s e r t e d n e a r t h e a p e x of t h e t r i a n g l e a n d d i r e c t e d p a r a l l e l to the midline at a 30 ° angle with the p a t i e n t supine (Figure 2). It is u s u a l l y most convenient to rotate the head 30 ° to 45 ° toward the cont r a l a t e r a l side. Local a n e s t h e s i a is used if the p a t i e n t is conscious and t i m e p e r m i t s . S e v e r a l m i l l i l i t e r s of saline are helpful to expel a n y plugs of tissue t h a t m a y e n t e r the needle after it passes t h r o u g h the skin. The needle is directed slightly l a t e r a l to the s a g i t t a l plane• D a r k venous blood will u s u a l l y be a s p i r a t e d at a depth of 2 to 3 cm. After a s p i r a t i n g blood, the protocol for cannulation, listed separately, should be followed. A b r i e f m e n t i o n of the special circ u m s t a n c e s in y o u n g children and inf a n t s s h o u l d be m a d e . One of t h e m o s t t e r r i f y i n g m o m e n t s in t h e
We have used this method of can, n u l a t i o n in t h r e e circumstances: 1) f a i l u r e t o c a n n u l a t e t h e interna} j u g u l a r v e i n on t h e s a m e side; 22 a n a t o m i c or o t h e r contraindication~ (old surgery, etc.) to i n t e r n a l jugula~ c a n n u l a t i o n ; and finally, 3) all case~ of c a r d i o r e s p i r a t o r y arrest. The sub~ c l a v i a n route is preferred in a r r e ~ p a t i e n t s b e c a u s e of the speed wit~ which t h e vein can be cannulated. Furi thermore, endotracheal intuba~ and subclavian catheterization~ be done s i m u l t a n e o u s l y . O b v i o u s ~ use of the i n t e r n a l j u g u l a r approa~ would prohibit s i m u l t a n e o u s i n t u ~ tion. However, e x t e r n a l cardiac com~ Pt~ession a n d v e n t i l a t i o n m u s t ~ ooped for about five to ten secon~ d u r i n g t h e c a n n u l a t i o n attempt. T h e r e a r e two a n a t o m i c a l : ~ p r o a c h e s for s u b c l a v i a n vein e ~ n u l i z a t i o n - - i n f r a c l a v i c u l a r an~ s u p r a c l a v i c u l a r . We have used th~ i n f r a c l a v i c u l a r approach most ofte~ A g r e a t deal of adverse publicity h ~ developed because of the r a t h e r h!.~ incidence of p n e u m o t h o r a x with th~ approach. TM As a result, the i n t e r n ~ j u g u l a r approach has been used mor~__ f r e q u e n t l y with its r e l a t i v e l y l o w ~ c i d e n c e of p n e u m o t h o r a x . 19,22,2~ ~ The s u b c l a v i a n vein (Figure 3), 3 - ~ cm long and 1 to 2 cm in diameter, a c o n t i n u a t i o n of the a x i l l a r v and extends from the outer m a r g i ~ the first rib to the medial border~the scalenus a n t e r i o r where it u n i ~ . 6:8 (Aug) 1977 J ~
f
Table 3 A N A T O M I C STRUCTURES THAT CAN BE INJURED BY SUBCLAVIAN C A N N U L A T I O N i
structure Subclavian artery
Anatomic Relation to Subclavian Vein (SV)
Error in Procedure
Injury
Posterior and slightly superior, separated by scalenus a n t e r i o r - - 10-15 mm in the adult, 5-8 mm in children.
Insertion too deep or laterally
Hemorrhage, hematoma & possible hemothorax
13rachial plexus
Posterior to and separated from SV by the scalenus anterior and subclavian artery (20 mm)
Same as w i t h subclavian artery
Possible motor sensory deficits of hand, arm or shoulder
parietal pleura
Contact w i t h p o s t e r i o r i n f e r i o r side of the SV, medial to the attachment of the anterior scalene muscle to the first rib
Needle p e n e t r a t e s beneath or t h r o u g h both walls of the SV
Pneumothorax
Phrenic nerve
Same as above
Placement of needle above or behind the vein or by penetration of both its walls
Paralysis of the ipsilateral hemi-diaphragm
Thoracic duct
Cross the s c a l e n u s a n t e r i o r and enter the superior margin of the SV near the internal jugular junction
Same as above
Soft t i s s u e l y m p h edema or chylothorax on left
Vagus nerve
Courses behind the internal jugular vein
Too long a n e e d l e inserted too deeply
Hoarseness
with the i n t e r n a l j u g u l a r v e i n to form the bracheocephalic vein. The clavicle and subclavius lie in front of it. Behind and above is the subclavian a r t e r y s e p a r a t e d by t h e scalenus a n t e r i o r m u s c l e . Below, it -rests in a shallow groove on the first rib and upon the pleura. 2s Obviously, there are p o t e n t i a l d a n g e r s i n the ~Wructures s u r r o u n d i n g the subcia~vvanvein ~.~ ITable 3~. After the s k i n is p r e p p e d a n d -6raped in a s t e r i l e f a s h i o n , local anesthesia is used to raise a wheal. =The point of insertion should be lojust l a t e r a l and inferior to the :junction of the middle a n d m e d i a l Ahirds of the clavicle. There are sev~t different ways of i n s e r t i n g the =v.eedle ~7 ~s 29 ao We prefer directing the needle toward the superior aspect of the s u p r a s t e r n a l notch after having advanced the tip of the needle ~ t beneath the inferior aspect of the ~aviele. The most i m p o r t a n t part of the whole procedure comes at this Point and the failure to observe this crucial point is one reason for serious "ff~plications. The syringe_ and neemust be held parallel to the pai r ' s back. The needle is then adVanced slowly with negative pressure ~v-er the f i r s t r i b a n d b e h i n d the ~=I~vicle, ~ at w h i c h t i m e t h e v e i n ~id be entered. Free flow of blood ~uld be n o t e d and t h e protocol ~ )
6:8 (Aug) 1977
should be followed to complete the procedure. Supraclavicular Cannulation (Tables 4 and 5). A n o t h e r a l t e r n a t e approach to c e n t r a l venous c a n n u l a t i o n is the s u p r a c l a v i c u l a r method. This method was developed p r i m a r i l y to avoid the major complications of the i n f r a c l a v i c u l a r method - - especially pneumothorax. ~1 The i m p o r t a n t l a n d m a r k fbr this method is the j u n c t i o n of the lateral border of the clavicular head of the sternocleidomastoid muscle and superior aspect of the clavicle. This can be visualized and easily palpated "in most patients. Since the o r i g i n a l description of this t e c h n i q u e by Yoffa, 31 there have b e e n s e v e r a l m o d i f i c a t i o f f s suggested, a2,a3 The " j u n c t i o n a l " stick has several theoretical advantages. In contrast to catheterization of the s u b c l a v i a n vein, the j u n c t i o n of the s u b c l a v i a n and the i n t e r n a l j u g u l a r v e i n is used. This has two a d v a n tages, a larger target and direction of the needle toward the m e d i a s t i n u m t h e r e b y a v o i d i n g the p l e u r a if the vein is missed. The skin is entered at the j u n c t i o n of the l a t e r a l a s s e t of the clawcular h e a d of t h e SC~I m u s c l e a n d the superior aspect of the clavicle. The needle is directed in the following
m a n n e r : s l i g h t l y p o s t e r i o r at a 5 ° angle from the coronal plane, at a 50 ° angle from the sagittal plane, and at a 40 ° a n g l e from t h e t r a n s v e r s e planeY 2 After blood is aspirated, the protocol is fbllowed IFigure 4/.
C O M P L I C A T I O N S (Tables 6 and 7) T h r e e c o m p l i c a t i o n s need to be mentioned: pneumothorax, arterial puncture, and air emholus. P n e u m o t h o r a x has occurred with some f r e q u e n c y w i t h the infi'aclavicular approach, especially under e m e r g e n c y circumstances, ls,21 Furt h e r m o r e , t h e f r e q u e n c y of p n e u mothorax is directly proportional to the i n e x p e r i e n c e of the p h y s i c i a n performing the procedure. Use of the i n t e r n a l j u g u l a r a p p r o a c h has resulted in a lower incidence of pneumothorax. To avoid a p n e u m o t h o r a x u s i n g the i n f r a c l a v i c u l a r approach, the syringe and needle m u s t be kept level with the ground and the needle m u s t h u g the u n d e r s u r f a c e of the clavicle. A r t e r i a l punctures occur in both the i n t e r n a l j u g u l a r and subclavian approaches, involving the subclavian and carotid arteries.17,19, 2a With the i n t e r n a l j u g u l a r approach, the carotid artery can be avoided by palpation before and d u r i n g i n s e r t i o n of the needle. The subclavian artery will be 362/31
Table 4 ADVANTAGES AND DISADVANTAGES OF TECHNIQUES Technique Basilic (peripheral)
Internal jugular
Advantages
Disadvantages
Low incidence of major complications
Greater incidence of minor complications of infection, p h l e b i t i s and thrombosis.
Allows large quantities of fluid to be given rapidly
More difficult to place catheter in correct position for central venous pressure monitoring
3. Prep the right neck and anteriQr'! chest wall almost to the nipple i
" B l i n d " procedure
5. Sterile technique is mandatory and it is most helpful to have a ready-made sterile CVP kit.
Good e x t e r n a l marks
land-
Lesser risk of pneumothorax than subclavian puncture
Has a slightly higher incidence of failures than subclavian
Bleeding can be recognized and controlled
More difficult and inconvenient to secure
Large rapid flow Useful a l t e r n a t i v e approach to cutdown in children under the age of two Good e x t e r n a l marks
land-
H i g h e r i n c i d e n c e of complications especially in hypovolemic shock
Large rapid flow
"Blind" procedure
Most practical method of inserting a central line in cardiorespiratory arrest
Should not be attempted in children underage two
Large rapid flow
" B l i n d " procedure
Good landmarks Less risk of pneumothorax than infraclavicular avoided if t h e p h y s i c i a n obeys t h e s a m e "safety rules" mentioned above with the p n e u m o t h o r a x . In t h e a d u l t t h e r e is 1 to 1.5 cm distance b e t w e e n vein and artery. U s u a l l y it will t a k e a deep stick to p u n c t u r e the a r t e r y . This is not true in infants and child r e n w h e r e t h a t d i s t a n c e is m u c h smaller. A i r embolus can be avoided bylS, is 1) p l a c i n g the p a t i e n t in the Trend e l e n b e r g p o s i t i o n to d i s t e n d t h e
4. Drape the area.
I
6. Disassemble the intracath and place needle on a 5 cc syringe, 7. Select site for cannulation. 8. Insert needle and maintain negative pressure until the free flow of blood is established. Immobilize the needle and remove the syringe covering the open end of the needle with a gloved thumb£ or finger. Some authors2°, 2~ use" an initial probe with a 21 gauge~ needle to locate the internal jug.t ular.
Carotid artery e a s i l y identified
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2. Have patient stripped to the:: waist and in Trendelenburg P0si,~ tion to distend the veins and Pre,, vent air embolism, i
Hinders free movement of arms
Almost a straight course to the superior vena cava on the right side
Supraclavicular functional)
1. Legitimate indication; no C0n,! traindications.
Performed under direct visualization of vein
Malposition of catheter is rare
Infraclavicular subclavian
Table 5 PROTOCOL FOR CATHETERIZATION
veins; 2) k e e p i n g a finger or t h u m b o v e r t h e h u b of t h e n e e d l e before t h r e a d i n g the catheter; 3) h a v i n g the p a t i e n t stop b r e a t h i n g and preferably p e r f o r m i n g V a l s a l v a ' s m a n e u v e r d u r i n g t h i s c r i t i c a l period, a n d finally, 4) ensure t h a t the i n t r a v e n o u s line fits s n u g l y into the c a t h e t e r to a v o i d d i s c o n n e c t i o n of t h e t u b i n g from the catheter_ This can be done by s p l i n t i n g the i n t r a v e n o u s t u b i n g to the c a t h e t e r w i t h a tongue blade and tape.
9. Thread 8" catheter through t ~ , needle. If any difficulty is encoun~ tered, try rotating catheter• If stili~ having difficulty, try rotating thiner. needle and then attempt t h r e a d i % 10. Do not force the c a t h e t e ~
~L
11. Never withdraw the cathete~ through the needle! J 12. After catheter is in place andJ stylet is withdrawn, attach largE syringe to catheter and aspirate~ to confirm position.
13. Withdraw the needle so thati it is completely visible. Use safety clip to immobilize needle against ~ catheter. 14. Attach the intravenous tubing and CVP manometer• 15. Secure catheter in place with suture. 16. Antibiotic ointment, 4 x 4's, Benzoin and tape. 17. Chest radiograph to assess location of catheter. 18. Check the fluid level in the manometer to insure that it fluctuates with respiration.
6:8 (Aug)1977 J ~ :
f
I n t e r p r e t a t i o n of CVP may be difficult_ It is i m p o r t a n t to use serial CVP m e a s u r e m e n t s r a t h e r t h a n one isolated reading. Knowledge of the p a t i e n t ' s clinical condition, i n c l u d i n g m e a s u r e m e n t s of blood p r e s s u r e , pulse rate, u r i n e output, etc., as well as his cardiac status, is essential in o r d e r to i n t e r p r e t c e n t r a l v e n o u s pressure accurately. Finally, the use of a fluid challenge is helpful in accurately assessing the patient's volume status. 4s
supraclavicula subclavian
site of needle entry for supr~ clavicular subclavian
Fig. 4.
CENTRAL VENOUS PRESSURE
Measurement. T h r e e factors are necessary to assure accurate central venous pressure m e a s u r e m e n t . First, the patient m u s t be supine. Second, the catheter must be p a t e n t and accurately located in the central veins. This can be d e t e r m i n e d by r a d i o .graphic localization o f the c a t h e t e r 4ip,4°,41 fluctuation of the column of fluid during respiration, and aspiration of blood after the c a t h e t e r is placed and before the m a n o m e t e r is ~nnected. Third, a baseline e x t e r n a l zero point should be established by marking a spot on the p a t i e n t so t h a t future r e a d i n g s can be t a k e n from ~he same point.
to c e n t r a l venous pressure is as follows: n o r m a l , 4~-45 5 to 12 cm H_~O; low, below 5 cm I-hO; high, above 12 to 15 cm I ~ O . All readings are t a k e n at end expiration.
The concept of fluid challenge and its t e c h n i q u e needs futher discussion due to its importance in the interpret a t i o n of c e n t r a l venous pressure. In order to assess either volume deficits or p u m p failure, aliquots of between 100 a n d 200 ml of crystalloid fluid are a d m i n i s t e r e d i n a s y s t e m a t i c m a n n e r . A reference pressure value is e s t a b l i s h e d d u r i n g a t e n - m i n u t e period of observation. The aliquot of fluid is r u n i n over the n e x t tenm i n u t e p e r i o d . If t h e C V P is in-
Table 6 COMPLICATIONS (GENERAL) Both peripheral and central:
L
There has been a great deal of debate concerning the location of the :zero point. A n u m b e r of a n a t o m i c a l sites have been recommended.4,23, 42 -tnpractice, we have used 40% to 45% of the anterior-posterior (AP) diameter of the chest, m e a s u r e d a n t e r i o r to posteriorly at the fourth intercostal space to approximate the location of the tricuspid valve. It is i m p o r t a n t to realize t h a t the absolute zero level is less i m p o r t a n t t h a n following serial measurements t a k e n at the same location a n d i n t h e s a m e m a n n e r . Changes in CVP with' serial measurements are an i m p o r t a n t diagnostic aid in the emergency d e p a r t m e n t . The common causes for incorrect central venous pressure r e a d i n g s are listed (Table 8).
Interpretation.
A rough g u i d e l i n e
6:8 (Aug)1977
1. Aberrant placement a. erroneous pressure readings b. perforation of veins c. arrhythmias d. perforation of myocardium with resultant pericardial tamponade e. hydromediastinum and hydrothorax
Solution These can be avoided by x-ray film confirmation after placement, anchoring the catheter in place, observing fluctuation of manometer level and the aspiration of free flowing blood after i n s e r t i o n of the catheter. 2. Catheter emboli: occurs usually under two circumstances: a. attempting to withdraw catheter through the needle b. catheter is cut while removing a suture
Solution Never w i t h d r a w catheter t h r o u g h the needle, withdraw catheter and needle as a unit. 3. Infections
Solution a. sterile technique b. rigid attention to site care c. percutaneous rather than cutdown technique d. removal as soon as possible 4. Thrombosis and thrombophlebitis
Solution a. percutaneous cannulation of large central veins with : ~ a p i d flow rather than peripheral vein b. avoid catheterization of leg veins - - femoral, saphenous, etc.
364/33
Table 7 S P E C I F I C C O M P L I C A T I O N S OF SUBCLAVIAN AND INTERNAL J U G U L A R M E T H O D S 7, 17-19,2g, 37-39
Table 8 C O M M O N C A U S E S FOR INCORRECT CENTRAL VENOUS PRESSURE READINGS 5
1. Pneumothorax
1. Patient has not been returned to level position from Trendelenburg after catheter inserted.
2. Arterial puncture
2. Incorrect zero point.
3. Bleeding from catheter site
3. Knot in the catheter or catheter is pinched by the protective "wing.,,
4. Air embolus
4. Changes in intrathoracic pressure (Valsalva, patient on respirator, tension pneumothorax).
5. Brachial plexus injury 6. Internal mammary - - subclavian only
injury
7. Thoracic duct injury 8. Osteomyelitis of clavicle - subclavian only
5. Catheter tip obstruction either by clot formation or occlusion against vessel wall. 6. Incorrect location: a. peripheral location b. right ventricle 7. Fluids running into manometer during measurement.
9. Phrenic injury 10. Vagus injury 11. Horner's syndrome
c r e a s e d b y m o r e t h a n 5 c m of w a t e r d u r i n g t h i s i n t e r v a l , t h e i n f u s i o n is d i s c o n t i n u e d . I f t h e C V P does n o t exceed its c o n t r o l v a l u e b y m o r e t h a n 2 c m I-leO a t t h e e n d o f t e n m i n u t e s , or if it d e c l i n e s to w i t h i n t h a t r a n g e o v e r a s e c o n d t e n - m i n u t e w a i t i n g period, t h e s e c o n d a l i q u o t is a d m i n i s t e r e d o v e r t e n m i n u t e s . T h i s process is repeated using two ten-minute seq u e n c e s , o n e for f l u i d a d m i n i s t r a t i o n a n d t h e s e c o n d f o r o b s e r v a t i o n of C V P . A p r o g r e s s i v e r i s e i n C V P exc e e d i n g 5 c m of w a t e r c o n s t i t u t e s indication of a limited cardiac competence_43, 44 W i t h so m a n y v a r i a b l e s p r e s e n t , it is c r i t i c a l to u s e g r e a t c a r e i n d r a w ing conclusions from CVP readings. Overestimating the information g a i n e d f r o m a C V P r e a d i n g is a r e a son central venous pressure has been a c o n t r o v e r s i a l topic. It is e s s e n t i a l to k n o w its l i m i t a t i o n s . B y u s i n g t h e f l u i d c h a l l e n g e t e c h n i q u e a n d correlating the measurements with the patient's cardiac status, the central v e n o u s p r e s s u r e is a u s e f u l aid to t h e emergency physician. REFERENCES 1. Huberty J, Schwartz R, Emich J: Central venous pressure monitoring. Obstet Gynecol 30:842-850, 1967. 2. Aubaniac R: Une nouvelle vole d'injection au de poncture veineuse: la voieclaviculaire. Sere Hop Paris 28:3445, 1952. 34/365
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nous catheters. Br Med J 7:595-597, 1975.
- /~ e ~ ASSOC d I U l l O ~ O - O ' i ~ I V u v ,
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42. Robson MD: Technique for obtaining reproducible central venous pressure. Johns Hopkins Med 122:232-235, 1968.
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43. D e b u m m e r F, Buhler F: Normal cent r a l v e n o u s p r e s s u r e , s i g n i f i c a n c e of r e f e r e n c e p o i n t and n o r m a l r a n g e . B r Med J 3:148-50, 1969.
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39. Adar R, M e z e s M: F a t a l complicat i o n s of c e n t r a l v e n o u s c a t h e t e r s . Br Med J 3:746, 1971.
45. W e i l MH, S h u b i n H: T h e " V I P " approach to the bedside m a n a g e m e n t of shock. J A M A 297:337-340, 1969.
40. Gilday D, Downs A: The v a l u e of chest r a d i o g r a p h y in the localization of c e n t r a l venous pressure catheters. Can
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