A newborn’s heart rate (HR) is the most important determinant of the need for and effectiveness of resuscitation. The ECG is recommended in the delivery room to monitor HR if available (ILCOR 2015) but application of electrodes can be challenging and electrical cardiac activity doesn’t always equate to adequate cardiac output. Use of pulse oximetry (POx) can underestimate the HR in the first few minutes of life and is unreliable in poor perfusion states [1]. We aimed to develop a newborn hat with an integrated green light photoplethysmography (PPG) HR sensor (SurePulse-SP) which can be quickly sited on the forehead offering an alternative to ECG and POx.

Babies were recruited from the neonatal unit (NNU) and prior to birth by term elective caesarean section (ECS) at the Nottingham University Hospitals NHS Trust. The SP hat was sited on the forehead and compared to ECG and pre-ductal POx for up to 30 minutes. Babies were excluded if there was no ECG data to compare, a protocol violation occurred or a device became detached from the patient. Manual checks were carried out against the raw ECG trace if the ECG HR and the test device HR diverged by ± 20%. The R-R intervals from the raw ECG trace over the disputed time period were calculated Pulmonology and Resuscitationmanually. Data was excluded if the ECG HR and the HR derived from the R-R interval of the raw ECG trace deviated by > 10%. Accuracy was determined using Bland-Altman analysis. Ethical approval was given.

A total of 60 babies (NNU = 40, ECS = 20) were recruited. After exclusions, 12,278 paired SP/ECG and 13,635 paired POx/ECG data points from 35 babies on the NNU (median 36 weeks; IQR 33-38 weeks) and 18 babies born by CS (median 39 weeks; IQR 39-39+6 weeks) were included. The Bland-Altman plots of HR differences for all patients showed SP and POx, compared to the ECG, had similar bias (-0.2; 0.2) but SP HR had narrower limits of agreement (LOA) (± 1.96 SD) 7.6, -8.0 than POx HR 10.1, -9.7 (Fig. 1). The Root-Mean-Square difference values of ECG HR-SP HR was 3.9 bpm compared to 5.0 bpm for ECG HR-POx HR. For subgroups analysis of NNU babies, SP (bias -0.2, LOA 7.5, -8.0) and POx (bias 0.1, LOA 7.7, -7.5) were comparable. For the ECS group, SP (bias 0, LOA 8.0, -8.0) performed better with narrow LOA compared to POx (bias 0.7, LOA 19.83, -18.35).

Forehead PPG offers an accurate, hands free alternative to POx and ECG in the delivery room. With the increasing use of delayed cord clamping, the challenges of attaching POx sensors, ECG leads and their cables, whilst considering temperature control, cannot be underestimated. Incorporating a wireless optical HR sensor within a hat ensures the normal care pathway is followed and could offer a number of advantages over existing methods.