Interposed Abdominal Compression CPR(lAC-CPR):A Glimmer of Hope

The first report of the use of abdominal pressure asan adjunct to resuscitation was by Crile in 1904.1 Al­though his success was not dramatic (one of six pa­tients survived), he believed that this simple techniquewas of potential benefit. Eve,2 Stout," and Rainer andBullough'' all reported variations on abdominal andchest compressions as resuscitative techniques.Shortly after the popularization of external cardiacmassage in 1960, Morgan! reported hepatic lacerationas a complication of this procedure. Subsequent re­ports of hepatic trauma with external cardiac massageand uniformly unsuccessful resuscitations were nu­merous. Of particular interest is the demonstration byThaler and Stobie" that abdominal compressions re­peatedly ruptured the liver in infants and small chil­dren. Harris et a(l showed increased carotid flow withcontinuous manual compression of the abdomen indogs; however, two of their six dogs had rupturedlivers at autopsy. They recommended abandonment ofthe technique, and their experience was confirmed byHooper." Redding? found increased flow and improvedsurvival with continuous abdominal compression CPRcompared with ordinary CPR and methoxamine-aug­mented CPR. In these studies, hepatic trauma wasequally common with and without abdominal binding.

The issue remained at rest until the first reports ofabdominal countermassage during external CPR camefrom Ohomoto et al.l? These investigators demon­strated improved coronary and carotid flows with thistechnique. Flows were optimized when chest com­pression occupied 30% of the cycle, with abdominalcompression starting one-quarter cycle ahead of chestcompression and occupying 80% of the cycle. Thetechnique of interposed abdominal compression CPR,first described by Ralston et al, I I was found to in­crease arterial pressures and cardiac output I I and toincrease oxygen uptake during CPR in dogs. 12 Thesestudies led this group to conclude that lAC-CPR "mayimprove resuscitation success." This conclusion hasbeen put to preliminary clinical trial by Berryman andPhillips,13 who demonstrated a 47% increase in meanarterial pressure with lAC-CPR compared with stan­dard CPR in six unresuscitatable cardiac arrest pa­tients. No hepatic lacerations were found at autopsy. 13

The most recent report on lAC-CPR from Voorheesand co-workers, published in this issue of AJEM, is awell-designed and carefully executed study. Using a

meticulously validated measurement technique, theywere able to demonstrate a 25% increase in cardiacoutput from 9.0% of spontaneous circulation withstandard CPR to 11.2% of control with lAC-CPR indogs. Although myocardial blood flow increased al­most in proportion to the increase in cardiac output,because of variation between animals this did notreach statistical significance at the P < 0.05 level.However, previous work indicating a threshold of car­diac resuscitability corresponding with myocardialflow> 0.2 ml/rnin/g" and a myocardial perfusionthreshold during CPR of 30 mm Hg diastolic pres­sure," led the authors to suggest that the small coro­nary flow and diastolic pressure improvementsachieved in this study could have a clinically signifi­cant impact on cardiac resuscitability and survival.

Measurements of cerebral blood flow (CBF) duringlAC-CPR also demonstrated only small improvement.Standard CPR produced 11.9% of spontaneous circu­lation CBF, whereas lAC-CPR produced 13.3% ofcontrol CBF. Although this improvement was statis­tically significant, the level of CBP achieved with IAC­CPR is still well below the "flow threshold of infarc­tion," thought to be 20% of normal CBP,15 It seemsunlikely that this small increase in CBP would haveany significant impact on neurologic outcome.

Voorhees and colleagues report no gross trauma toabdominal viscera after lAC-CPR; specifically, noliver lacerations were observed during postmortem ex­amination. This is of obvious importance, because thesafety of this technique must be clearly establishedbefore it can be recommended for widespread clinicaluse. It should be noted that this technique is not ap­plicable for basic life support because of the high riskof aspiration if performed on a patient with an unpro­tected airway. Also, the risk of hypoventilation duringlAC-CPR must be considered and investigated. Fi­nally, outcome studies in animals should first demon­strate unequivocal benefit in terms of neurologic aswell as cardiac functional recovery before clinicaltrials are undertaken.

Interposed abdominal compression CPR presents aglimmer of hope and ultimately may prove to be verybeneficial. However, at present it must be consideredan experimental technique requiring further animal in­vestigation before prospective, well-controlled, ran­domized clinical trials are undertaken. It is only when

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AMERICAN JOURNAL OF EMERGENCY MEDICINE. Volume 2, Number 2

the preceding steps have been accomplished that thistechnique should be recommended for widespreadclinical use.

NICHOLAS G. BIRCHER, MDNORMAN S. ABRAMSON, MDResuscitation Research. CenterUniversity ofPittsburghPittsburgh, Pennsylvania

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2. Eve FC. Artificial circulation produced by rocking: Its usein drowning and anesthetic emergencies. Br Med J1947 ;2:295.

3. Stout HA. Cardiac arrest: Massage without incision. J OklaState Med Assoc 1957;50:112.

4. Rainer EH, Bullouqh J. Respiratory and cardiac arrestduring anesthesia in children. Br Med J 1957;2:1024.

5. Morgan RR. Laceration of the liver from closed-chest car­diac massage. N Engl J Med 1961 ;265:82.

6. Thaler MM, Stobie GHC. An improved technique of external

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cardiac compression in infants and young children. NEngl J Med 1963;269:606.

7. Harris LC, Kirimli B, Safar P. Augmentation of artificial cir­culation during cardiopulmonary resuscitation. Anesthe­siology 1967;28:730.

8. Hooper AC. Complications of experimental cardiac mas­sage. Ir J Med Sci 1970;3:435.

9. Redding JS. Abdominal compression during cardiopulmo­nary resuscitation. Anesth Analg 1971 ;50:668.

10. Ohomoto T, Miura I, Konno S. A new method of externalcardiac massage to improve diastol lc augmentation andprolong survival times. Ann Thorac Surg 1976;21 :284.

11. Ralston SH, Babbs CF, Niebauer MJ. Cardiopulmonary re­suscitation with interposed abdominal compression indogs. Anesth Analg 1982;61 :645.

12. Voorhees WD, Niebauer MJ, Babbs CF. Improved oxygendelivery during cardiopulmonary resuscitation with inter­posed abdominal compressions. Ann Emerg Med1983;12:128.

13. Berryman CR, Phillips GM. Preliminary results from Inter­posed abdominal compression-CPR In human subjects.Ann Emerg Med 1983;12:249.

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