- Email: [email protected]
Apparatus for the determination of venous pressure in man
APPARATUS
R. W.
FOR THE DETERMINATION PRESSURE IN MAN* M.D.,
KISSANE,
AND
COLUMBUS,
OF VENOUS
R. 8. KOOES, M.D. OHIO
ENOUS pressure is obtained in man by two methods, the direct and the indirect. The technic of the direct method requires the inserting of a large needle or trocar into a superficial vein of the forearm, and the connecting of the column of blood directly with a manometer upon which the pressure is read. The factors that make this procedure impracticable are the necessity of a sterile technic, possibility of the blood clotting, trauma to the vein, pain and other objections of the patient, and the inability to make repeated pressure determinations. The indirect method depends upon the principle that the least pressure applied outside a vein required to actuate collapse will be practically equal to the pressure within the vein. Numerous instruments having either a water or a mercury manometer have been devised for this purpose, but they are expensive and repairs are diffieult. The use of the water manometer is the most suitable, but the reading is hard to obtain because the column of water fluctuates to such a marked degree while pressure is being applied over the vein.
V
CONSTRUCTION
These objections have prompted the present,ation of a modified apparatus for the determination of venous pressure in man by the indirect method. It consists of an ordinary thistle tube (1) , over which has been tightly stretched a piece of a rubber glove (2), which has a small opening in its center (3)) and is held taut and in place by a rubber band (4). The thistle tube is connected by rubber tubes and a T-tube (5) to a water manometer (6) and an ordinary rubber blood-pressure cuff (7). A pressure bulb(8) with an esc,ape valve (9) is attached to the other opening of the rubber bag or cuff. The construction of the manometer is a glass tube bent in a manner (13) so as to have one end close to the bottom of a small glass reservoir (11). The manometer tube is connected to the reservoir through one of two openings in a rubber stopper (12)) while an L-tube (10) through The manometer tube the other connects with the rest of the apparatus. and the reservoir are mounted upon a base board beside a meter stick (14). After the reservoir and the curved end of the manometer tube are partly filled with colored water, the meter stick is adjusted so that 0 is opposite the level of the water in the long arm of the tube. If the fluid level is a short distance above this point, the number of millimeters can be subtracted from the pressure reading. pital,
*From the Columbus,
Cardiological Ohio.
Departnients
of White
705
Crass
HoslGtal
and
Children’s
Has-
706
TTIE
AMERICAN
IIEART
JOURNAI,
METHOD
The patient is placed in a semi-recumbent position with the right arm extended so that t,he hand is brought to a level with the right auricle of the heart. A large superficial vein of the hand is srlected and surrounded by a ring of vaseline or water soluble jelly. The thist,le tube is placed against the hand in such a manner that, the opening in the rubber diaphragm is directly over the vein. In this position the vein can be watched through the glass thistle tube while air is pumped in by means of the pressure bulb. The reading is made in millimeters on t,he meter stick the instant the vein is collapsed.
This instrument is inexpensive and can be made in any laboratory without requiring mechanical skill. The rubber bag or cuff acts as a buffer and allows the water to rise slowly and evenly in the manometer tube, thereby facilitating the ease and accuracy of the reading. The apparatus can be easily and rapidly repaired without requiring expensive parts. The apparatus is made portable by draining the water from the tube and the reservoir and refilling at the bedside.
R. W.
FOR THE DETERMINATION PRESSURE IN MAN* M.D.,
KISSANE,
AND
COLUMBUS,
OF VENOUS
R. 8. KOOES, M.D. OHIO
ENOUS pressure is obtained in man by two methods, the direct and the indirect. The technic of the direct method requires the inserting of a large needle or trocar into a superficial vein of the forearm, and the connecting of the column of blood directly with a manometer upon which the pressure is read. The factors that make this procedure impracticable are the necessity of a sterile technic, possibility of the blood clotting, trauma to the vein, pain and other objections of the patient, and the inability to make repeated pressure determinations. The indirect method depends upon the principle that the least pressure applied outside a vein required to actuate collapse will be practically equal to the pressure within the vein. Numerous instruments having either a water or a mercury manometer have been devised for this purpose, but they are expensive and repairs are diffieult. The use of the water manometer is the most suitable, but the reading is hard to obtain because the column of water fluctuates to such a marked degree while pressure is being applied over the vein.
V
CONSTRUCTION
These objections have prompted the present,ation of a modified apparatus for the determination of venous pressure in man by the indirect method. It consists of an ordinary thistle tube (1) , over which has been tightly stretched a piece of a rubber glove (2), which has a small opening in its center (3)) and is held taut and in place by a rubber band (4). The thistle tube is connected by rubber tubes and a T-tube (5) to a water manometer (6) and an ordinary rubber blood-pressure cuff (7). A pressure bulb(8) with an esc,ape valve (9) is attached to the other opening of the rubber bag or cuff. The construction of the manometer is a glass tube bent in a manner (13) so as to have one end close to the bottom of a small glass reservoir (11). The manometer tube is connected to the reservoir through one of two openings in a rubber stopper (12)) while an L-tube (10) through The manometer tube the other connects with the rest of the apparatus. and the reservoir are mounted upon a base board beside a meter stick (14). After the reservoir and the curved end of the manometer tube are partly filled with colored water, the meter stick is adjusted so that 0 is opposite the level of the water in the long arm of the tube. If the fluid level is a short distance above this point, the number of millimeters can be subtracted from the pressure reading. pital,
*From the Columbus,
Cardiological Ohio.
Departnients
of White
705
Crass
HoslGtal
and
Children’s
Has-
706
TTIE
AMERICAN
IIEART
JOURNAI,
METHOD
The patient is placed in a semi-recumbent position with the right arm extended so that t,he hand is brought to a level with the right auricle of the heart. A large superficial vein of the hand is srlected and surrounded by a ring of vaseline or water soluble jelly. The thist,le tube is placed against the hand in such a manner that, the opening in the rubber diaphragm is directly over the vein. In this position the vein can be watched through the glass thistle tube while air is pumped in by means of the pressure bulb. The reading is made in millimeters on t,he meter stick the instant the vein is collapsed.
This instrument is inexpensive and can be made in any laboratory without requiring mechanical skill. The rubber bag or cuff acts as a buffer and allows the water to rise slowly and evenly in the manometer tube, thereby facilitating the ease and accuracy of the reading. The apparatus can be easily and rapidly repaired without requiring expensive parts. The apparatus is made portable by draining the water from the tube and the reservoir and refilling at the bedside.