Chest Compressions during Sustained Inflations Improve Recovery When Compared to a 3:1 Compression:Ventilation Ratio during Cardiopulmonary Resuscitation in a Neonatal Porcine Model of Asphyxia

Abstract

Background: Recently, sustained inflations (SI) during chest compression (CC) (CC+SI) have been suggested as an alternative to the current approach during neonatal resuscitation. No previous study compared CC+SI using CC rates of 90/min to the current 3:1 compression:ventilation ratio (C:V). Objective: To determine whether CC+SI versus a 3:1 C:V reduces the time to the return of spontaneous circulation (ROSC) and improves hemodynamic recovery in newborn piglets with asphyxia-induced bradycardia. Intervention and Measurements: Term newborn piglets were anesthetized, intubated, instrumented, and exposed to 45-min normocapnic hypoxia followed by asphyxia. Cardiopulmonary resuscitation (CPR) was initiated when the heart rate decreased to 25% of baseline. Piglets were randomized into 3 groups: CC during SI at a rate of 90 CC/min (SI+CC 90, n = 8), a 3:1 C:V using 90 CC and 30 inflations (3:1, n = 8), or a sham group (n = 6). Cardiac function, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment. Results: CC+SI significantly reduced the median (IQR) time of ROSC, i.e., 34 s (28-156 s) versus 210 s (72-300 s) in the 3:1 group (p = 0.048). CC+SI also significantly reduced the requirement for 100% oxygen, improved respiratory parameters, and resulted in a similar hemodynamic recovery. Conclusions: CC+SI during CPR significantly improved ROSC in a porcine model of neonatal resuscitation. This is of considerable clinical relevance because improved respiratory and hemodynamic parameters potentially minimize morbidity and mortality in newborn infants.

Effects of sustained inflation pressure during neonatal cardiopulmonary resuscitation of asphyxiated piglets

“…We have previously demonstrated that using CC+SI with a PIP of 30 cmH 2 O significantly improves ROSC and survival in asphyxiated newborn piglets, compared to using the coordinated 3:1 compression-to-ventilation ratio (C:V) [18,19,21]. However, the optimal PIP for delivering SI during CC remains unknown.…”

“…Despite extensive studies during the last decade, the most effective method of delivering CC remains controversial. We have previously demonstrated that providing a sustained inflation (SI) during CC (CC+SI) significantly improves return of spontaneous circulation (ROSC) and survival in newborn piglets [18][19][20][21]. Our primary aim was to determine whether different PIP during CC+SI would affect time to ROSC and survival in newborn piglets with asphyxia-induced asystole.…”

Comparison of Different Compression to Ventilation Ratios (2: 1, 3: 1, and 4: 1) during Cardiopulmonary Resuscitation in a Porcine Model of Neonatal Asphyxia

“…These studies suggest that during neonatal CPR, different C:V ratios do not improve outcomes and might not be the optimal CC approach in newborn infants. In comparison with the recommended 3: 1 C:V, combining CC with sustained inflation has been shown to be more effective in improving ROSC in piglets [15, 22-24], but not in lambs [25]. …”

“…However, the duration of CPR or C:V ratios did not change the levels of lung inflammation. Similarly, different CC techniques (e.g., 3: 1 C:V vs. CC during sustained inflation) did not increase levels of lung inflammation [15]. …”

“…Piglets were instrumented as previously described with modifications [15]. Following the induction of anesthesia using isoflurane, the piglets were intubated via a tracheostomy, and pressure-controlled ventilation (Acutronic Fabian; Hirzel, Switzerland) was commenced at a respiratory rate of 16–20 breaths/min and pressure of 20/5 cm H 2 O.…”