A comparison of chest compressions between mechanical and manual CPR by monitoring end-tidal PCO2 during human cardiac arrest.

STUDY OBJECTIVE: To compare the use of mechanical and manual chest compressions during cardiac arrest based on continuous monitoring of end-tidal PCO2 (PETCO2). DESIGN: Prospective, randomized, crossover design. SETTING AND PARTICIPANTS: Fifteen consecutive adults ranging in age from 33 to 78 years who presented in nontraumatic cardiac arrest to the emergency department of a large teaching hospital. INTERVENTIONS: Study protocols were begun late in the resuscitation after initial resuscitation attempts were unsuccessful. Patients received four alternating five-minute trials (two manual and two mechanical), being randomized to begin with either technique. Mechanical compressions were performed by a mechanical device at a compression depth of 2 in. Both mechanical and manual compressions were delivered at a rate of 80 with a ventilation delivered after every fifth compression. Persons performing manual CPR were experienced American Heart Association basic life support providers, and no person performed manual CPR more than once during the study period. No resuscitative drugs were administered during the study period. PETCO2 was monitored continuously; those performing manual CPR were blinded to the PETCO2 monitor. Data were analyzed with repeated-measures analysis of variance and Scheffé multiple comparisons with the alpha error rate set of .05. MEASUREMENTS AND RESULTS: Mean PETCO2 during mechanical CPR was 13.6 +/- 4.14 mm Hg compared with 6.9 +/- 2.42 mm Hg during manually performed CPR (P < .001), a difference of 97%. Average mechanical CPR PETCO2 was higher in all cases. No patient was resuscitated successfully. Capnography also indicated that most CPR providers were inconsistent in their chest compressions. CONCLUSION: This study suggests that cardiac output produced with mechanical chest compressions is greater than that produced with manual compressions as demonstrated by the significantly higher PETCO2 levels during mechanical CPR. Reasons for this are unclear. In addition, monitoring of PETCO2 may help optimize chest compressions during CPR.

A comparison of interposed abdominal compression CPR and standard CPR by monitoring end-tidal PCO2.

Interposed abdominal compression CPR (IAC-CPR) has been demonstrated to significantly improve blood flow compared with standard (S)-CPR in animal and electrical models. Studies with IAC-CPR in human beings have not reported data regarding cardiac output. Animal and clinical studies have correlated end-tidal PCO2 (ETPCO2) with cardiac output produced with precordial compressions. We conducted a prospective, randomized study on 33 adult patients with nontraumatic cardiac arrest. Patients were randomized to initially receive either S-CPR or IAC-CPR. ETPCO2 was monitored continuously. After 20 minutes of resuscitation, the technique was reversed. The average ETPCO2 during IAC-CPR was 17.1 mm Hg while the average during S-CPR was 9.6 mm Hg, a difference of 78% (P less than .001). In patients arriving in cardiac arrest, return of spontaneous circulation was observed in six patients (30%) during IAC-CPR and in one patient (6%) during S-CPR (P = .07). Our study strongly suggests that cardiac output may be significantly increased in human beings with IAC-CPR as evidenced by the significantly greater increases in ETPCO2 with IAC-CPR compared with S-CPR. In addition, IAC-CPR appeared to demonstrate a trend toward increasing the return of spontaneous circulation.

Heat stroke New Orleans style.

An in-depth discussion of Classic Heat Stroke (CHS) and Exertional Heat Stroke (EHS) Syndromes occurred during morning report at a large metropolitan teaching institution during a New Orleans heat wave. The opportunity arose to compare the syndromes via case reports of two patients admitted the same day to the same housestaff teams. The physiology of the hyperthermic state, maladaptions predisposing the hyperthermic syndrome and current heat stroke management updates are reviewed in detail. This report should compel the reader to remain attentive to the subtleties and differences presented in life-threatening high-heat and humidity-related illnesses and how to act rapidly and prudently in management of the illnesses.