Sylvia van Os

Exhaled carbon dioxide can be used to guide respiratory support in the delivery room

Respiratory support in the delivery room remains challenging. Assessing chest rise is imprecise, and mask leak and airway obstruction are common problems. We describe recordings of respiratory signals during delivery room resuscitations and discuss guidance on positive‐pressure ventilation using respiratory parameters and exhaled carbon dioxide (ECO2) during neonatal resuscitations.

Spontaneously Breathing Preterm Infants Change in Tidal Volume to Improve Lung Aeration Immediately after Birth

OBJECTIVE To examine the temporal course of lung aeration at birth in preterm infants <33 weeks gestation. STUDY DESIGN The research team attended deliveries of preterm infants <33 weeks gestation at the Royal Alexandra Hospital. Infants who received only continuous positive airway pressure were eligible for inclusion. A combined carbon dioxide (CO2) and flow-sensor was placed between the mask and the ventilation device. To analyze lung aeration patterns during spontaneous breathing, tidal volume (VT), and exhaled CO2 (ECO2) were recorded for the first 100 breaths. RESULTS Thirty preterm infants were included with a total of 1512 breaths with mask leak <30%. Mean (SD) gestational age and birth weight was 30 (1) weeks and 1478 (430) g. Initial VT and ECO2 for the first 30 breaths was 5-6 mL/kg and 15-22 mm Hg, respectively. VT and ECO2 increased over the next 20 breaths to 7-8 mL/kg and 25-32 mm Hg, respectively. For the remaining observation period VT decreased to 4-6 mL/kg and ECO2 continued to increase to 35-37 mm Hg. CONCLUSIONS Preterm infants begin taking deeper breaths approximately 30 breaths after initiating spontaneous breathing to inflate their lungs. Concurrent CO2 removal rises as alveoli are recruited. Lung aeration occurs in 2 phases: initially, large volume breaths with poor alveolar aeration followed by smaller breaths with elimination of CO2 as a consequence of adequate aeration.

Using exhaled CO2 to guide initial respiratory support at birth: a randomised controlled trial

Importance A sustained inflation (SI) provided at birth might reduce bronchopulmonary dysplasia (BPD). Objective This study aims to examine whether an SI-guided exhaled carbon dioxide (ECO2) compared with positive pressure ventilation (PPV) alone at birth decreases BPD. Design Randomised controlled trial. Infants were randomly allocated to either SI (SI group) or PPV (PPV group). Participants Participants of this study include infants between 23+0 and 32+6 weeks gestation with a need for PPV at birth. Intervention Infants randomised into the SI group received an initial SI with a peak inflation pressure (PIP) of 24 cmH2O over 20 s. The second SI was guided by the amount of ECO2. If ECO2 was ≤20 mm Hg, a further SI of 20 s was delivered. If ECO2 was >20 mm Hg the second SI was 10 s. Infants randomised into the PPV group received mask PPV with an initial PIP of 24 cmH2O. Primary outcomes Reduction in BPD defined as the need for respiratory support or supplemental oxygen at corrected gestational age of 36 weeks. Results SI (n=76) and PPV (n=86) group had similar rates of BPD (23% vs 33%, p=0.090, not statistically significant). The duration of mechanical ventilation was significantly reduced with SI versus PPV (63 (10–246) hours versus 204 (17–562) hours, respectively (p=0.045)). No short-term harmful effects were identified from two SI lasting up to 40 s (eg, pneumothorax, intraventricular haemorrhage or patent ductus arteriosus). Conclusion Preterm infants <33 weeks gestation receiving SI at birth had lower duration of mechanical ventilation and similar incidence of BPD compared with PPV. Using ECO2 to guide length of SI is feasible. Trial registration number NCT01739114; Results.

Analysis of neonatal resuscitation using eye tracking: a pilot study

Background Visual attention (VA) is important for situation awareness and decision-making. Eye tracking can be used to analyse the VA of healthcare providers. No study has examined eye tracking during neonatal resuscitation. Objective To test the use of eye tracking to examine VA during neonatal resuscitation. Methods Six video recordings were obtained using eye tracking glasses worn by resuscitators during the first 5 min of neonatal resuscitation. Videos were analysed to obtain (i) areas of interest (AOIs), (ii) time spent on each AOI and (iii) frequency of saccades between AOIs. Results Five videos were of acceptable quality and analysed. Only 35% of VA was directed at the infant, with 33% at patient monitors and gauges. There were frequent saccades (0.45/s) and most involved patient monitors. Conclusion During neonatal resuscitation, VA is often directed away from the infant towards patient monitors. Eye tracking can be used to analyse human performance during neonatal resuscitation.

Chest compression during sustained inflation versus 3:1 chest compression:ventilation ratio during neonatal cardiopulmonary resuscitation: a randomised feasibility trial

Background Current neonatal resuscitation guidelines recommend 3:1 compression:ventilation (C:V) ratio. Recently, animal studies reported that continuous chest compressions (CC) during a sustained inflation (SI) significantly improved return of spontaneous circulation (ROSC). The approach of CC during SI (CC+SI) has not been examined in the delivery room during neonatal resuscitation. Hypothesis It is a feasibility study to compare CC+SI versus 3:1 C:V ratio during neonatal resuscitation in the delivery room. We hypothesised that during neonatal resuscitation, CC+SI will reduce the time to ROSC. Our aim was to examine if CC+SI reduces ROSC compared with 3:1 C:V CPR in preterm infants <33 weeks of gestation. Study design Randomised feasibility trial. Method Once CC was indicated all eligible infants were immediately and randomly allocated to either CC+SI group or 3:1 C:V group. A sequentially numbered, brown, sealed envelope contained a folded card box with the treatment allocation was opened by the clinical team at the start of CC. Study interventions Infants in the CC+SI group received CC at a rate of 90/min during an SI with a duration of 20 s (CC+SI). After 20 s, the SI was interrupted for 1 s and the next SI was started for another 20 s until ROSC. Infants in the ‘3:1 group’ received CC using 3:1 C:V ratio until ROSC. Primary outcome Overall the mean (SD) time to ROSC was significantly shorter in the CC+SI group with 31 (9) s compared with 138 (72) s in the 3:1 C:V group (p=0.011). Conclusion CC+SI is feasible in the delivery room. Trial registration number Clinicaltrials.gov NCT02083705, pre-results.

Oxygen Saturation and Heart Rate Ranges in Very Preterm Infants Requiring Respiratory Support at Birth

Objective To evaluate the changes in preductal oxygen saturation (SpO2) and heart rate in preterm infants receiving continuous positive airway pressure (CPAP) and/or positive‐pressure ventilation (PPV) at birth. Study design A prospective observational study at birth of infants aged <32 weeks separated into 2 gestational age (GA) groups: 230/7‐276/7 weeks (group 1) and 280/7‐316/7 weeks (group 2). Infants received delayed cord clamping (DCC) in accordance with institutional protocol. CPAP and/or PPV was applied at the clinical teams discretion. SpO2 and heart rate were recorded every minute for 10 minutes. Preductal SpO2 was targeted according to published nomograms. For heart rate, the goal was to maintain a stable heart rate >100 bpm. Results The study cohort comprised 96 group 1 infants (mean GA, 26 ± 1 weeks; mean birth weight, 818 ± 208 g) and 173 group 2 infants (mean GA, 30 ± 1 weeks; mean birth weight, 1438 ± 374 g). In general, infants requiring respiratory support reached target values for heart rate and SpO2 more slowly than the published nomograms for spontaneously breathing preterm infants without respiratory support. Infants receiving CPAP reached SpO2 and heart rate targets faster than infants receiving PPV. In group 1, but not group 2 infants, DCC resulted in higher SpO2 and heart rate. Conclusion SpO2 and heart rate do not quickly and reliably reach the values achieved by spontaneously breathing preterm infants not requiring respiratory support.

Impact of changing clinical practices on early blood gas analyses in very preterm infants and their associated inpatient outcomes

Background Early studies suggest an association of abnormal carbon dioxide (PCO2) or oxygen (PO2) levels with adverse inpatient outcomes in very preterm babies. Recent resuscitation practice changes, such as targeted oxygen therapy, end-expiratory pressure, and rescue surfactant may influence these associations. Objective The aim of this study is to assess the range of the initial partial pressures of PCO2 and PO2 in preterm neonates <33 weeks gestational age after birth and their correlation to inpatient neonatal outcomes. Study design This is a prospective observational cohort study of infants <33 weeks gestational age with arterial or venous blood gas analysis performed within the first hour after birth. Results One hundred seventy infants (arterial n = 75, venous n = 95) with mean (SD) gestational age of 28 (3) weeks and birth weight of 1,111 (403) g were included. None of the infants with arterial blood gases had hypocarbia (<30 mmHg), 32 (43%) had normocarbia (30–55 mmHg), and 43 (57%) had hypercarbia (>55 mmHg). Seventeen of the infants with arterial blood gases (22%) had hypoxia (<50 mmHg), 50 (67%) normoxia, and 8 (11%) hyperoxia (>80 mmHg). In infants with venous blood samples, none had venous PCO2 < 40 mmHg, 41 (43%) had venous PCO2 40–60 mmHg, and 54 (57%) had venous PCO2 > 60 mmHg. Multivariable logistic regression analysis showed no association of low or high PCO2 or PO2 with death or major inpatient morbidities. Conclusion With current resuscitation and stabilization practices, hyperoxia and hypocarbia was uncommon, and hypercarbia occurred frequently. None of these findings correlate with adverse inpatient outcomes or death. Our findings are in direct contrast to published observations using historical practices.

Comparison of positive pressure ventilation devices in a newborn manikin

Abstract Objective: To compare tidal volume (VT) delivery and ventilation rate between devices for positive pressure ventilation (PPV) during newborn resuscitation. Methods: Neonatal resuscitation program providers (n = 25) delivered PPV to a newborn manikin in a randomized order with: a self-inflating bag (SIB), a disposable T-piece, a non-disposable T-piece, a stand-alone infant resuscitation system T-piece and the volume-controlled prototype Next StepTM device (KM Medical). All T-pieces used a peak inflation pressure of 20cmH2O and a 5cmH2O positive end-expiratory pressure (PEEP). The SIB neither had a PEEP valve nor manometer. The Next StepTM had a 5cmH2O PEEP valve. The participants aimed to deliver a 5 mL/kg VT (rate 40–60 min−1) for 1 min with each device and each of three compliances (0.5, 1.0 and 2.0 mL/cmH2O). VT and ventilation rate were compared between devices and compliance levels (ANOVA) Results: All devices, except the Next StepTM delivered a 4–5 mL/kg VT at the low compliance, but three- to four-fold that of the target at the higher compliance levels. The Next StepTM delivered a VT close to target at all compliance levels. The ventilation rate was within 40–60 min−1 with all devices and compliance levels. Conclusions: Routinely used ventilation devices for newborn resuscitation can triple intended VT and requires further investigation.

Ventilation Strategies during Neonatal Cardiopulmonary Resuscitation

Approximately, 10–20% of newborns require breathing assistance at birth, which remains the cornerstone of neonatal resuscitation. Fortunately, the need for chest compression (CC) or medications in the delivery room (DR) is rare. About 0.1% of term infants and up to 15% of preterm infants receive these interventions, this will result in approximately one million newborn deaths annually worldwide. In addition, CC or medications (epinephrine) are more frequent in the preterm population (~15%) due to birth asphyxia. A recent study reported that only 6 per 10,000 infants received epinephrine in the DR. Further, the study reported that infants receiving epinephrine during resuscitation had a high incidence of mortality (41%) and short-term neurologic morbidity (57% hypoxic-ischemic encephalopathy and seizures). A recent review of newborns who received prolonged CC and epinephrine but had no signs of life at 10 min following birth noted 83% mortality, with 93% of survivors suffering moderate-to-severe disability. The poor prognosis associated with receiving CC alone or with medications in the DR raises questions as to whether improved cardiopulmonary resuscitation methods specifically tailored to the newborn could improve outcomes.

a novel Prototype neonatal resuscitator That controls Tidal Volume and Ventilation rate: a comparative study of Mask Ventilation in a newborn Manikin

The objective of this randomized controlled manikin trial was to examine tidal volume (VT) delivery and ventilation rate during mask positive pressure ventilation (PPV) with five different devices, including a volume-controlled prototype Next Step™ device for neonatal resuscitation. We hypothesized that VT and rate would be closest to target with the Next Step™. Twenty-five Neonatal Resuscitation Program providers provided mask PPV to a newborn manikin (simulated weight 1 kg) in a randomized order with a self-inflating bag (SIB), a disposable T-piece, a non-disposable T-piece, a stand-alone resuscitation system T-piece, and the Next Step™. All T-pieces used a peak inflation pressure of 20 cmH2O and a positive end-expiratory pressure of 5 cmH2O. The participants were instructed to deliver a 5 mL/kg VT (rate 40–60/min) for 1 min with each device and each of three test lungs with increasing compliance of 0.5, 1.0, and 2.0 mL/cmH2O. VT and ventilation rate were compared between devices and compliance levels (linear mixed model). All devices, except the Next Step™ delivered a too high VT, up to sixfold the target at the 2.0-mL/cmH2O compliance. The Next Step™ VT was 26% lower than the target in the low compliance. The ventilation rate was within target with the Next Step™ and SIB, and slightly lower with the T-pieces. In conclusion, routinely used newborn resuscitators over delivered VT, whereas the Next Step™ under delivered in the low compliant test lung. The SIB had higher VT and rate than the T-pieces. More research is needed on volume-controlled delivery room ventilation.