Efficacy of continuous insufflation of oxygen combined with active cardiaccompression-decompression during out-of-hospital cardiorespiratory arrest

Background: During experimental cardiac arrest, continuous insufflation of air or oxygen (CIO) through microcannulas inserted into the inner wall of a modified intubation tube and generating a permanent positive intrathoracic pressure, combined with external cardiac massage, has previously been show n to be as effective as intermittent positive pressure ventilation (IPPV). Methods: After basic cardiorespiratory resuscitation, the adult patients wh o experienced nontraumatic, out-of-hospital cardiac arrest with asystole, w ere randomized to two groups: an IPPV group tracheally intubated with a sta ndard tube and ventilated with standard IPPV and a CIO group for whom a mod ified tube was inserted, and in which CIO at a flow rate of 15 1/min replac ed IPPV (the tube was left open to atmosphere). Both groups underwent activ e cardiac compression-decompression with a device. Resuscitation was contin ued for a maximum of 30 min, Blood gas analysis was performed as soon as st able spontaneous cardiac activity was restored, and a second blood gas anal ysis was performed at admission to the hospital. Results: The two groups of patients (47 in the IPPV and 48 in the CIO group ) were comparable. The percentages of patients who underwent successful res uscitation (stable cardiac activity; 21.3 in the IPPV group and 27.1% in th e CIO group) and the time necessary for successful resuscitation (11.8 +/- 1.8 and 12.8 +/- 1.9 min) were also comparable. The blood gas analysis perf ormed after resuscitation (8 patients in the IPPV and 10 in the CIO group) did mt show significant differences. The arterial blood gases performed aft er admission to the hospital and ventilation using a transport ventilator ( seven patients in the IPPV group and six in the CIO group) showed that the partial pressure of arterial carbon dioxide (Pa-CO2) was significantly lowe r in the CIO group (35.7 +/- 2.1 compared with 72.7 +/- 7.4 mmHg), whereas the pH and the partial pressure of arterial oxygen (Pa-O2) were significant ly higher (all P < 0.05). Conclusions: Continuous insufflation of air or oxygen alone through a multi channel open tube was as effective as IPPV during out-of hospital cardiac a rrest. A significantly greater elimination of carbon dioxide and a better l evel of oxygenation in the group previously treated with CIO probably refle cted better lung mechanics.