Influence of different types of recovery positions on perfusion indices of the forearm

resuscitation

Resuscitation 32 (1996) 13-17

Influence of different types of recovery positions on perfusion indices of the forearm J. Rathgeber*, W. Panzer, U. Giinther, M. Scholz, A. Hoeft, J. Bahr, D. Kettier Dqmrtment

of Anuesthesblogy, Emergency and Intensive Care Medirine, Georg-August-U

Gatrtbgen.

Robert-Koch-Strasse40, D-37075 Gcittingen.Germany Received 21 September MJS; revised 20 November l!l95; accepted 31 December 1595

Backgm~ Basic life support guidelines of the European Resuscitation Council (ERC) sullppst a m&r type of reco~ry position compnmd to that recoannended by the Amet%an Heart Association (AHA). However, anecdotal reports and the results da small study by F&tow and Smith @esuscitation 1993;26: 89-91) gave evidmux that the new ERC position may causean impairmeat of perfusion of the lower forearm. The aim of our study was to evshtate the ctkta of different recovery positions on arteriaf perfusion and venous d&a* of the forearm. Methods: We placed 20 young healthy voluateers randomly in either ERC or AHA position for 15 mia fmt, and in the other position thereah. Befon and between volunteers were positioned supine. In a second series 10 volunteers were po&oned according to the sameprotm1 in semiprone positions as described by Morrison, Mirakhur and Craig (MMC), and Rautek’s position, mspectively. Forearm perfusion indices of the dependeot arm were continuously amessedby photop#ethysmographicpulsatility change, photoplethysmographic vohune chaage, invasive peripti venous pressure and non-invasive blood pressureamplitude. Subjective discomfixt was assess&nonqtmbtutMy. Restdts~Ah iadices of arterial perfusion demonstrated an impairment of arteM inflow in ERC, MMC and Rautek’a p&ion as ~$1 as venous coage&oa in these three positions. Oa the contrary, AHA position was associated with no SisDificant chaqea of arteM Row and only moderate, ins&&ant signs of venous cong&on. Conch&n: The results of this study suggestthat AHA position causesless circulatory disturbances then the ERC, MMC and Rautek’s positions. &ywvr&:

Recovery position; Perfusion; Venous congestion; Arterial iatlow

1. 1m In 1992tk Rasic Life Support Working Party of the European Resuscitation Council (ERC) issued new guidelines [ 11,including a type of recovery po* Cormponding

author.

sition differing from previously recomded ones. In the American Heart AsxGatkm (AHA) is rollform (semi-prone position) [2] the ed onto his side ucrosshis m, which t.&& pts to lie do&y (Fig, 1). In the new ERC po&tb the (afterwards lower) arm is f&y placed out on the rescuer’s side at a right angle, the casualty is then

030@[email protected] 0 1996Elaevier Science Ireland Ltd. AU rights reserved PII SO300-9572(96)00952-S

14

J. Rathgeber et al. /Resuscitation

Fig. 1. The AHA position.

rolled, so that both arms get placed on one side (Fig. 2). The new ERC position was thought to producea near lateral body position and to be performed more easily by the rescuer. However, anecdotalreports and the findings of a study by Fulstow and Smith suggestedthat this position might result in an impairment of perfusion of the lower arm [3,4]. Compromisedarterial blood supply, venousocclusion,blotchy skin mottling, discomfort and pain in the lower arm were reported. Since our first comparison of the AHA and ERC positions in fact showedcirculatory disturbancesin the ERC position, presumablycausedby the position of the lower shoulder,the question of whether they might be influencedby the crossing of the arms arose.In a secondserieswe therefore comparedthe ERC position with other, lesscommonly applied recovery positions described by Morrison, Miiakhur and Craig (MMC) [5] and Rautek [6]. These are more similar to the ERC than to the AHA recommendations,but do not require positioning the arms one upon the other. Either the dependentarm (MMC, Fig. 3) or the upper arm (Rautek, Fig. 4) lies extendednext to the trunk. All three forms with the casualtylying in a near lateral body position in fact seemto be easier to handle for the rescuer than the AHA position.

Fig. 2. The ERC position.

32 (19%) 13-17

Fig. 3. The MMC position.

This study was designedto investigatethe effects of different recoverypositions on perfusion indicesof the lower arm. Severalperfusion indices of both forearmswere continuously monitored in the respectiverecovery positions and were compared to the previous supine period. 2. Materials and methods 2.1. Positions The study was performedafter approval by the local Ethics Committee.In a fust series20 young healthyvolunteerswere randomly placedin either AI-IA or ERC position for 15 min first, and then in the other position, thereafter.In a secondseries we positioned 10of the volunteersin MMC and in Rautek’sposition accordingto the sameprotocol. Before and betweenrecoverypositions volunteers were positioned supine. 2.2. Measurements Photoplethysmographicpulsatility index (PPI) and photoplethysmographicvolume index (PVI) were assessedwith a pulse oximeter (Criticare Systems),which was spatially modified for assess-

Fig. 4. Rautek’s position.

J. Rathgeberet al. /Resuscitation32 (1%) 13-l 7

ment of quantitative photoplethysmographic data. Pulse oximetry is well known as a method for qualitative capillary perfwion measurement 1731. It sendslight of two different wavelengths (660 nm (red) and 940 nm (infrared)), and detects light intensities reduced by absorption after passageof the respective tissue. The total absorption is caused by different components in the tissue. A nonpulsatile part is determined by skin, pigmentation, bone, venous blood and more (basic absorbance). Arterial capillary perfusion causesa pulsatile component (pulse added absorbance). Therefore, the signal detected by the pulse oximeter probe comprises a non-pulsatile component (DC, Fig. 5) which is mainly determined by the basic absorbance, and a pulsatile component (AC, Fig. 5) which is determined by the pulse added absorbance, If venous congestion increasesthe proportion of non-pulsatile blood in the linger, the basic absorbance is increased. Thus, the intensity of detectedlight (DC), which corresponds to the nonpulsatile component, is decreased,and the ratio of the incident light (IO) divided by DC is a photoplethysmographic index of the finger volume (photoplethysmographic volume index (PVI) = I@C), as a parameter for venous congestion. Similarly, the ratio of the amplitude of the pulsatile component of the waveform (AC) nor-

_._ .-._-_ -.--..__... ____-..--. ___--. T---%!JfdL%C _..-- _._-. _._..._ -._ --._. .___.. __. .__ t I

DC

i Fig. 5. Pu&tik and non-p&Mile component of pulse oximeter signal. DC, basic absorbance; AC, pulse added absorbance.

15

malized by the non-pulsatile component of detected light (photoplethysmographic pulsatility index (PPI) = AC/DC) represents a parameter for arterial capillary perfusion. Finger probes were positioned on both index fingers. Non-invasive peripheral blood pressure amplitude (PBA) was determined by continuous oscillometric measurement (Ohmeda Finapres”), with the probe attached to the middle finger of the dependent hand. Venous congestion was measured by puncture of peripheral veins on the back of the dependent hand (peripheral venous pressure, PVP), with a pressuretransducer placed on the wrist connected to a Hellige Patient Monitor@. Subjective discomfort and pain were assessed non-qualitatively by items “Yes“ and “No“. 2.3. Statistical analysis Data were averaged over 5 min at the end of each position period, and n to the preceding supine position. Statistical analysis was performed with Wilcoxon matched pair test. PValues of less than 0.05 were considered to indicate statistical significance. Results are presented as box-plots, showing median, lOth, 25th, 75th and 90th percentiles. 3. Results

The results for the pulsatility index, blood pressure amplitude, volume index, and venous pressure are shown in Figs. 6-9. All recovery positions except the AHA one were found to decreasePPI and PBA, whereas PVI and PVP were increased. Only a small increase of PVI and PVP was observed during the AHA position. In the ERC position 11 out of 20 volunteers reported discomfort and pain concerning the dependent arm (Table l), versus four out of 20 in AHA, five out of 10 in MMC and four out of 10 in Rautek’s position, respectively. 4. DisewsIon that arterial The results of this study su inflow is significantly impaired in all recovery

16

J. Rathgeber et al. /Resuscitaiion

32 (19%) 13-17

*

120 , 100 80

80

60

J **

40 20 0

*

60

*

I

L

-20

9%! e!

-40 -60 i -80 +rAHA

ERC

MMC

-20

Rautek

Fig. 6. Photopkthysmographic pulsatility index (PPI). Change in percentage of supine position. All boxplots: median; Ioth, 25th. 7sth, 96th pcrcexltil~. “P < 0.05.

I AHA

I ERC

I MMC

I Rautek

J

Fig. 8. Photoplethysmographic volume index (PVI). Change in pwcentagc of supineposition. All boxplots: median; IO&, 25th, 75th, 90th percentiles. ‘P < 0.05.

1200 1100 1000 900 800 700 600 500 400 300 200 100 -50

’

I

I

I

I

AHA

ERC

MMC

Rautek

Fig. 7. Peripheral blood pressure amplitude (PBA). Change in percentageof supine position. All boxplots: median; lOth, 25th, 75th 90th percentiles. l P < 0.05.

0 AHA

ERC

MMC

Rautek

Fig. 9. Peripheral venous pressure(PVP). Change in percentage of supine position. AU boxplots: modian, 10th. 25% 75th, 90th percenti. l P < 0.05.

J. Rathgeber et al. /Resuscitation 32 (19%) 13-37 Table 1 Numbers of volunteers reporting discomfort in recovery positions

DiSCOVlfOft

No discomfort

ERC

AHA

MMC

Rautek

11 9

4 16

5 5

4 6

positions investigatedexcept the AM position. Moreover, the photoplethysmographic volume index as well as the peripheral venous pressure indicate a venous congestion, which is less pronouncedin the AHA position than in all others.In addition, less volunteers complained about discomfort in the AHA position than in the other

17

sition as currently proposed is used. There is no doubt that unconsciousspontaneouslybreathing patients should be placed in a recoveryposition, except in cases of any of the few contraindications. Since some recovery positions can causecirculatory disturbancewe concfudethat our findings should be taken into account when discussing any subsequent recommendation. Looking forward to uniform guidelinesfrom the AHA and the ERC, it seemsto be of great importancethat the lower arm is positionedbe&ml (dorsal) the victim’s body rather than in front, acceptingthat this may compror&sethe preferred near vertical position. Another conclusion is that any future recoveryposition should be subjected to similar studiesevaluating possibleimpairment of perfusion and nerve function. Rd-

OIKS.

In principle, neurological symptoms like paresthesiacan be causedeither by direct nerve compressionor by nerval ischemia. Our results suggestthat in fact with the ERC, MMC and Rautek’s positions circulation of the dependent arm is alternated, which may explain the neurologicalphenomena[9,10,11I. It is commonly acceptedthat paresthesiais primarily causedby neural ischemia.In the AHA position, the dependent arm getsto lie dorsally and the shoulderis at leastpartially placedbesidesthe chest.In the ERC position, and also in the MMC and Rat&k’s positions, both arms get placed ventrally, the dependent arm hasto traversebelow the rib cage,so that both the brachialplexusand vesselsare likely to be pinched betweenthe first rib and the clavicle. In the ERC position, bra&al vesselscan also be compromised, since both arms get placed one upon the other. Generally, in all positions, one must consider whether the bra&al plexus might be directly strained as a result, for example,by dorsal extensionand lateral flexion of the head, since the bra&al plexus is fmed to the uzrvical vertebraeand the axillary fascia. In summary, for positioning over extended periodswe cannot reliably excludenerve ‘njury by ischemiaor compression,if the ERC reccwerypo-

1113asic

Life Support Working Party of tbe European Rmuacitatim Coumd. Guidcliaes for basic life support. Resuscitation 1992;24: 103-110. 121Emargeucycardiaccarecoulmit*aud-ttee, foflxwdiq?lIlAmericnu Herut Associntion. ca&accare.JAm mouary res~tation aud elmplcy Mad Assoc 1992;268: 2171-295. [31 F&tow R, Smith GB. The new mcovery position, a cautiowy title. Resuscitation 1993;26: 89-91. [41 Handley AJ. Recovery position. Resuscitation 1993;26: 93-95. PI Morrison JD, Mirakhur RK, Craig HJI. An&be&a for eye, ear, nose and throat surgery. E&burgh: Churchill Living&one, London, 1985. 161Ahnefeld FW. &&u&en entacheickn. L&msmttende sofoe. 3erlh sprhgnr, 1967; 70-n. I71 Kim JM, Arakawa K, Reman KT, Fox DK. Pulseoximetfyandt3imatorykinetiGB @ Pm= volume amplitude meaamed by M&Ysmography. Aneath Analg 1986; Is1 Kim JM, Arakawn K, von Lintel T. Use of tbe p&cwave monitor as a measurement of tic sympathetic block and of surgical sympathetomy. Anesth Analg 1975;54: 289-296. 191 Lincoln JR, Sawyer HP. Comphcations r&ted to body positions during surgical procedures. Anesthesiology 1961;22: 800-809. WI Dawson DM. Krarup C. Perioperative nerve Iesions. Arch Neural 1989;46: 1355-1360. [Ill Km11DA, Gq.&tn RA, FormerK, Ward RJ, Cheney FW. Nerve injury associatedwith anesthesia.AnesthesiololTy 1990;73: 202-207.