Assessment of optimal chest compression depth during neonatal cardiopulmonary resuscitation: a randomised controlled animal trial

Abstract

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.

Respiratory function monitoring during neonatal resuscitation: A systematic review

“…Studies with respiratory function monitoring have demonstrated that changes in tidal volume occur during transition at birth, 15 a positive relationship between tidal volume delivered and increase of heart rate during this transition, 16 the contribution of spontaneous breathing to the tidal volume in newborn infants being provided positive pressure ventilation 17 , 18 and tidal volume changes during cardiac compressions. 19 Clinically, respiratory function monitoring via mechanical ventilators is commonly used in the neonatal intensive care unit (NICU) as a feedback tool. 20 However, it is not routinely used to monitor ventilation during neonatal resuscitation.…”

Chest Compression Rates of 90/min versus 180/min during Neonatal Cardiopulmonary Resuscitation: A Randomized Controlled Animal Trial

“…The automated CC machine was custom designed in our laboratory. The settings for the automated CC machine were anterior-poster depth 33%, acceleration of compression 500 cm/s 2 , speed of recoil 50 cm/s, a simulated two-thumb technique, and a CC rate of 90/min or 180/min according to group allocation [ 12 , 13 ].…”

“…A FlexiForce A201 sensor (TekScan, Boston, MA, USA) was placed on the bottom of the plunger of the automated CC machine to measure the applied compression force. The applied compression force was recorded with Arduino Software (Somervile, MA, USA) with a sample rate of 200 Hz [ 12 , 13 ].…”

“…Following surgical instrumentation and stabilization, the piglets were placed onto the automated CC machine, which was placed on the surgical bed. The piglets’ chest diameter was measured from the sternum to the vertebrae touching the bed (anterior to posterior) with a measuring tape, and then the anterior-posterior depth of 33% was calculated [ 12 , 13 ]. Piglets were then exposed to 45 min of normocapnic hypoxia, which was followed by asphyxia.…”

“…Fifteen seconds after asystole, positive pressure ventilation was provided for 30 s with a Neopuff T-Piece (Fisher & Paykel, Auckland, New Zealand) with 21% oxygen, peak inspiratory pressure of 30 cmH 2 O, positive end-expiratory pressure of 5 cmH 2 O, gas flow of 8 L/min, and at a rate of 50/min. After 30 s of positive pressure ventilation, mechanical CC using our automated CC machine was initiated [ 12 , 13 ] using 21% oxygen [ 14 , 15 ], with an antero-posterior chest diameter depth of 33% [ 12 , 13 ], and continuous CC was initiated during sustained inflation (CC + SI) with a peak inspiratory pressure of 30 cmH 2 O for 30 s [ 16 , 17 , 18 ]. Sustained inflation was interrupted for 1 s before a further 30 s of sustained inflation was provided, and this was continued until ROSC [ 5 ].…”