AimThe study aimed to examine the optimal anterior-posterior depth which will reduce the time to return of spontaneous circulation and improve survival during chest compressions. Asphyxiated neonatal piglets receiving chest compression resuscitated with a 40% anterior-posterior chest depth compared with 33%, 25% or 12.5% will have reduced time to return of spontaneous circulation and improved survival.MethodsNewborn piglets (n=8 per group) were anaesthetised, intubated, instrumented and exposed to 45 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to four intervention groups (‘anterior-posterior 12.5% depth’, ‘anterior-posterior 25% depth’, ‘anterior-posterior 33% depth’ or ‘anterior-posterior 40% depth’). Chest compressions were performed using an automated chest compression machine with a rate of 90 per minute. Haemodynamic and respiratory parameters, applied compression force, and chest compression depth were continuously measured.ResultsThe median (IQR) time to return of spontaneous circulation was 600 (600–600) s, 135 (90–589) s, 85 (71–158)* s and 116 (63–173)* s for the 12.5%, 25%, 33% and 40% depth groups, respectively (*p<0.001 vs 12.5%). The number of piglets that achieved return of spontaneous circulation was 0 (0%), 6 (75%), 7 (88%) and 7 (88%) in the 12.5%, 25%, 33% and 40% anterior-posterior depth groups, respectively. Arterial blood pressure, central venous pressure, carotid blood flow, applied compression force, tidal volume and minute ventilation increased with greater anterior-posterior chest depth during chest compression.ConclusionsTime to return of spontaneous circulation and survival were similar between 25%, 33% and 40% anterior-posterior depths, while 12.5% anterior-posterior depth did not result in return of spontaneous circulation or survival. Haemodynamic and respiratory parameters improved with increasing anterior-posterior depth, suggesting improved organ perfusion and oxygen delivery with 33%–40% anterior-posterior depth.Trial registration numberPTCE0000193.

Background: To compare chest compression (CC) rates of 90/min with 180/min and their effect on the time to return of spontaneous circulation (ROSC), survival, hemodynamic, and respiratory parameters. We hypothesized that asphyxiated newborn piglets that received CC at 180/min vs. 90/min during cardiopulmonary resuscitation would have a shorter time to ROSC. Methods: Newborn piglets (n = 7/group) were anesthetized, intubated, instrumented and exposed to 45 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to a CC rate of 180/min or 90/min. CC was performed using an automated chest compression machine using CC superimposed with sustained inflation. Hemodynamic and respiratory parameters and applied compression force were continuously measured. Results: The mean (SD) time to ROSC was 91 (34) and 256 (97) s for CC rates of 180/min and 90/min, respectively (p = 0.08). The number of piglets that achieved ROSC was 7 (100%) and 5 (71%) with 180/min and 90/min CC rates, respectively (p = 0.46). Hemodynamic parameters (i.e., diastolic and mean blood pressure, carotid blood flow, stroke volume, end-diastolic volume, left ventricular contractile function) and respiratory parameters (i.e., minute ventilation, peak inflation and peak expiration flow) were all improved with a CC rate of 180/min. Conclusion: Time to ROSC and hemodynamic and respiratory parameters were not statistical significant different between CC rates of 90/min and 180/min. Higher CC rates during neonatal resuscitation warrant further investigation.

BackgroundCurrent neonatal resuscitation guidelines recommend that chest compressions (CCs) be delivered at a rate of 90/min. The aim of the study was to investigate the haemodynamic effects of different CC rates in a neonatal piglet model.MethodsSix asphyxiated piglets were randomised to CC with rates of 60/min, 90/min, 120/min, 150/min and 180/min for 1 min at each rate. CCs superimposed with sustained inflations were performed with an automated CC machine.ResultsSix newborn piglets (age 0–3 days, weight 2.0–2.3 kg) were included in the study. Overall, there was a gradual increase in stroke volume, minimum and maximum rate of left ventricle pressure change (dp/dtmin and dp/dtmax), and carotid blood flow until CC rate of 150/min, with a level-off effect at a CC rate of 180/min. However, cardiac output continued to increase with the highest being at a CC rate of 180/min.ConclusionRate of CC was associated with changes in haemodynamic parameters during cardiopulmonary resuscitation. CC rate of 150–180/min during CC resulted in the highest cardiac output and arterial blood pressure.Trial registration numberPreclincialtrials.eu PCTE0000249.

Introduction: Neonatal chest compression (CC) should be performed to a 1/3 anterior-posterior (AP) chest diameter depth, however, the optimal AP depth is unknown. Hypothesis: We hypothesized that in asphyxiated neonatal piglets a 40% AP depth compared to 1/3, or 1/4 AP depth will reduce time to achieve return of spontaneously circulation and improve survival. Methods: Newborn piglets (n=8/group) were anesthetized, intubated, instrumented, and exposed to 45-minute normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to four intervention groups (“AP 12.5% depth”, “AP 1/4 depth”, “AP 1/3 depth” or “AP 40% depth“). CCs were performed using an automated CC machine with a rate of 90/min. Hemodynamic and respiratory parameters were continuously measured. Results: Median (IQR) time to return of spontaneously circulation was 70 (60-117), 85 (72-90), 90 (90-130), and 600 (600-600) sec with AP 40% depth, AP 1/3 depth, AP 1/4 depth, AP 12.5% depth, respectively. No piglet in the AP 12.5% depth group achieved ROSC while the short-term survival (1h) in the other groups was 100%. Systolic and diastolic blood pressure, central venous pressure, carotid blood flow, tidal volume, and minute ventilation increased with increasing AP depth. Conclusions: Time to return of spontaneously circulation and survival was similar between 1/4, 1/3, and 40% AP depth, while 12.5% AP depth did not result in return of spontaneously circulation. Hemodynamic and respiratory parameters improved with increasing AP depth suggesting that 40% AP depth might provide improved organ perfusion and oxygen delivery.