Chest compressions in newborn infants: a scoping review

Aim: The International Liaison Committee on Resuscitation Neonatal Life Support Task Force undertook a scoping review of the literature to identify evidence relating to neonatal cardiopulmonary resuscitation.

Methods: MEDLINE complete, EMBASE and Cochrane database of Systematic reviews were searched from inception to November 2021. Two authors screened titles and abstracts and full text reviewed. Studies were eligible for inclusion if they were peer-reviewed and assessed one of five aspects of chest compression in the newborn infant including: (1) heart rate thresholds to start chest compressions (CC), (2) compression to ventilation ratio (C:V ratio), (3) CC technique, (4) oxygen use during CC and 5) feedback devices to optimise CC.

Results: Seventy-four studies were included (n=46 simulation, n=24 animal and n=4 clinical studies); 22/74 were related to compression to ventilation ratios, 29/74 examined optimal technique to perform CC, 7/74 examined oxygen delivery and 15/74 described feedback devices during neonatal CC.

1) Heart rate threshold to initiate chest compressions:

- No study examined different heart rate thresholds to initiate chest compressions in newborn infants in the delivery room.

2) Different compression:ventilation ratios:

- Manikin and animal studies compared 3:1 with either 2:1, 4:1, 9:3 or15:2 C:V and reported no difference in survival, time to ROSC.

2) Continuous chest compression with asynchronised ventilation (CCaV):

- Several animal studies reported no difference in outcomes for 3:1 C:V and CCaV.

2) CC superimposed during sustained inflations (CC+SI):

- Four animal studies and a pilot randomised trial in the delivery room compared 3:1 C:V with CC+SI

- In animal studies, survival improved with CC+SI in one study20 but was similar in the other three.

In three animal studies, time to ROSC was significantly decreased with CC+SI, while one study did not find a difference in time to ROSC.

- The pilot trial randomized nine preterm infants <33 weeks’ reported mean (SD) time to ROSC was 31 (9) with CC+SI and 138 (72) s with 3:1 C:V, with similar survival

3) Chest compression technique:

- Thirty-one studies (29 randomized crossover manikin studies and 2 clinical trials) compared various finger/hand positions and the use of assistive compression devices.

- This scoping review confirmed that two-thumb- techniques resulted in improved chest compression depth, lower fatigue and higher proportion of correct hand placement compared with two-finger technique.

- Several alternative finger and/or hand position techniques during chest compression have been examined. These newer chest compression techniques resulted in similar performance measures when compared with the two-thumb-technique.

4) Supplemental oxygen during chest compressions:

- Seven animal studies investigating the effect of different inspired oxygen (O2) concentrations during chest compressions.

- No difference in time to ROSC or survival with either 21% or 100% O2.

5) Chest compression feedback devices:

- Sixteen studies compared chest compression feedback devices including 12 manikin studies, 3 animal studies and 1 clinical study.

- There are no current recommendations from the ILCOR Neonatal Life Support Task Force addressing the use of aids to improve compression depth and proportion of correct hand placement or decreasing fatigue.

Conclusion: There were very few clinical studies and mostly manikin and animal studies. The findings either reinforced or were insufficient to change previous recommendations which included to start CC if heart rate remains <60/min despite adequate ventilation, using a 3:1 C:V ratio, the two-thumb encircling technique and 100% oxygen during CC.