Cardiorespiratory Monitoring during Neonatal Resuscitation for Direct Feedback and Audit.

Neonatal resuscitation is one of the most frequently performed procedures, and it is often successful if the ventilation applied is adequate. Over the last decade, interest in seeking objectivity in evaluating the infant's condition at birth or the adequacy and effect of the interventions applied has markedly increased. Clinical parameters such as heart rate, color, and chest excursions are difficult to interpret and can be very subjective and subtle. The use of ECG, pulse oximetry, capnography, and respiratory function monitoring can add objectivity to the clinical assessment. These physiological parameters, with or without the combination of video recordings, can not only be used directly to guide care but also be used later for audit and teaching purposes. Further studies are needed to investigate whether this will improve the quality of delivery room management. In this narrative review, we will give an update of the current developments in monitoring neonatal resuscitation.

Influence of the hand squeeze and mask distensibility on tidal volume measurements during neonatal mask ventilation.

BACKGROUND: During mask ventilation, the mask volume can vary as it is pressurized or when it is squeezed. The change in volume of the mask may affect tidal volumes delivered and difference in inspired (Vti) and expired tidal volumes (Vte). OBJECTIVES: To investigate whether hand squeeze and distensibility of the mask during ventilation influences tidal volume measurements. METHODS: For both experiments, we ventilated a leak-free mask ventilation model using pressures of 25/5 cm H2O through a t-piece. Vti and Vte were measured. (A) Two consultants performed mask ventilation with (1) consistent hand squeeze, (2) release during inflation and squeeze during expiration, (3) squeeze during inflation, release during expiration, and (4) gentle squeeze. RESULTS: (B) Thirty caregivers performed mask ventilation. Experiment A: Vti was different during consistent hold (1) 8.1 ml (0.4) and loose grip (4) 8.2 ml (0.3), compared to squeezing during inflation (2) 18.9 ml (1.9), or expiration (3) 6.4 ml (3.5). Variance in difference between Vti and Vte occurred only when the mask was squeezed during inflation (-47.4% (101.5)). Experiment B: volumes measured were consistent (intraindividual CV 3-5%, interindividual CV 9-10%). When comparing gas flow rate of 6-10 l/min, volumes increased by approximately 8%, differences in Vti and Vte were small with both flow settings (-0.9% (-3.9-1.4) and -0.6% (-3.3-1.8); n.s.). CONCLUSION: Variation in mask hold during mask ventilation can influence volume measurement, but this hardly occurs when testing caregivers.

Mask versus nasal tube for stabilization of preterm infants at birth: a randomized controlled trial.

OBJECTIVE: Positive-pressure ventilation (PPV) using a manual ventilation device and a face mask is recommended for compromised newborn infants in the delivery room (DR). Mask ventilation is associated with airway obstruction and leak. A nasal tube is an alternative interface, but its safety and efficacy have not been tested in extremely preterm infants. METHODS: An unblinded randomized controlled trial was conducted in Australia, and the Netherlands. Infants were stratified by gestational age (24-25/26-29 weeks) and center. Immediately before birth infants were randomly assigned to receive PPV and/or continuous positive airway pressure with either a nasal tube or a size 00 soft, round silicone mask. Resuscitation protocols were standardized; respiratory support was provided using a T-piece device commencing in room air. Criteria for intubation included need for cardiac compressions, apnea, continuous positive airway pressure >7 cm H2O, and fraction of inspired oxygen >0.4. Primary outcome was endotracheal intubation in the first 24 hours from birth. RESULTS: Three hundred sixty-three infants were randomly assigned; the study terminated early on the grounds of futility. Baseline variables were similar between groups. Intubation rates in the first 24 hours were 54% and 55% in the nasal tube and face mask groups, respectively (odds ratio: 0.97; 95% confidence interval: 0.63-1.50). There were no important differences in any of the secondary outcomes within the whole cohort or between the 2 gestational age subgroups. CONCLUSIONS: In infants at <30 weeks' gestation receiving PPV in the DR, there were no differences in short-term outcomes using the nasal tube compared with the face mask.

Evaluating manual inflations and breathing during mask ventilation in preterm infants at birth.

OBJECTIVE: To investigate inflations (initial sustained inflations and consecutive inflations) and breathing during mask ventilation in preterm infants at birth. STUDY DESIGN: Resuscitation of infants <32 weeks' gestation receiving mask ventilation at birth were recorded. Recorded waveforms were divided into inflations (sustained and consecutive inflations), breaths in between inflations, breaths coinciding with an inflation, and breaths on continuous positive airway pressure (during evaluation moments in between and after ventilation) and expiratory tidal volume (V(Te)) was compared. Inflations were analyzed for leak, low V(Te) (<2.5 mL/kg), high V(Te) (>15 mL/kg in sustained inflations, >10 mL/kg in consecutive inflations), and airway obstruction. RESULTS: In 27 infants, we analyzed 1643 inflations, 110 breaths in between inflations, 133 breaths coinciding with an inflation, and 1676 breaths on continuous positive airway pressure. A large mask leak frequently resulted in low V(Te). Breathing during positive pressure ventilation occurred in 24 of 27 infants (89%). Median (IQR) V(Te) of inflations, breaths in between inflations, and breaths coinciding with an inflation were 0.8 mL/kg (0.0-5.6 mL/kg), 2.8 mL/kg (0.7-4.6 mL/kg), and 3.9 mL/kg (0.0-7.7 mL/kg) during sustained inflations and 3.7 mL/kg (1.4-6.7 mL/kg), 3.3 mL/kg (2.1-6.6 mL/kg), and 4.6 mL/kg (2.1-7.8 mL/kg) during consecutive inflations, respectively. The V(Te) of breaths were significantly lower than the V(Te) of inflations or breaths coinciding with an inflation. CONCLUSIONS: We often observed large leak and low V(Te), especially during sustained inflations. Most preterm infants breathe when receiving mask ventilation and this probably contributed to the stabilization of the infants after birth.

Auditing resuscitation of preterm infants at birth by recording video and physiological parameters.

OBJECTIVE: To evaluate compliance with neonatal resuscitation guidelines during resuscitation of preterm infants by video recording of delivery room management and monitoring physiologic parameters. METHODS: The delivery room management of preterm infants at birth was recorded by an independent researcher. Physiological parameters (airway pressures, gas flow, tidal volume, heart rate and oxygen saturation) were measured, use of supplemental oxygen was noted and a video of the resuscitation was recorded. All signals were digitised and recorded using specially designed software. The delivery room management was then evaluated and compared with the local resuscitation guidelines. RESULTS: Thirty-four infants were included with a mean (SD) gestational age of 30.6 (3.2) weeks and birth weight of 1292 (570) g. Time from birth to initial evaluation was longer than recommended (65 (15) s). Respiratory support was started at 70 (23) s. In 7/34 infants (21%), interventions were performed according to guidelines. In 25/34 infants (74%), one or more respiratory interventions were not performed according to guidelines. In 10/34 infants (29%), one or more non-respiratory interventions (mainly related to the prevention of heat loss) were not performed according to guidelines. The presence and adequacy of spontaneous breathing was difficult to judge clinically. In almost all occasions (96%) the information from the respiratory function monitor was not used. CONCLUSIONS: Neonatal caregivers often deviate from resuscitation guidelines. Respiratory function monitoring parameters were often not used during resuscitation. A difficult part of neonatal resuscitation is subjectively assessing spontaneous breathing.

Compressive force applied to a manikin's head during mask ventilation.

OBJECTIVE: To investigate the compressive force applied to the head during mask ventilation and determine whether this force increases in response to an attempt to correct the mask leak. METHODS: The authors asked 24 participants (consultants, fellows and nurses) to administer positive pressure ventilation to a modified leak-free, term newborn manikin using a self-inflating bag (SIB) and a Neopuff T-piece device. Recordings were made before and after the participants were informed about their percentage of mask leak and asked to correct this. Airway pressure and flow were measured using a Florian monitor, and the force applied to the head was measured using a concealed custom-made load cell weighing scale. RESULTS: There were no differences in the mean (SD) force applied to the head between devices used and before or after the attempt to correct the mask leak (SIB before 2215 (892) and after 2195 (989) g; Neopuff before 1949 (957) and after 2028 (909) g). There was a large variation in force with both devices before and after the attempt (coefficient of variation: SIB before 40% and after 45%; Neopuff before 50% and after 45%). There was no correlation between mask leak and the difference in force used before and after the attempt to correct the mask leak using both devices. CONCLUSION: During mask ventilation of a manikin, the authors observed that large forces were exerted on the head with either an SIB or a Neopuff, but these forces did not increase during the attempt to minimise the mask leak.

Changing gas flow during neonatal resuscitation: a manikin study.

INTRODUCTION: When using a T-piece device, resuscitators may try to improve airway pressures by increasing gas flow instead of correcting face mask position. AIM: To measure the effects of changing gas flow during positive pressure ventilation (PPV) on peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP), expiratory tidal volume (V(Te)) and mask leak. METHODS: Using a Neopuff T-piece device, 20 neonatal staff members delivered PPV to a modified, leak-free manikin. Resuscitation parameters were recorded. Study A: PPV for 4 min at PIP 30 cm H(2)O and PEEP 5 cm H(2)O. Each minute gas flow was increased (5, 8, 10, and 15 L/min). PIP and PEEP settings were unchanged. Study B: same pressure settings; PPV for 1 min with 5, 8, 10, and 15 L/min in a random order, at a rate of ∼ 60/min. The pressures were adjusted to maintain the same PIP and PEEP after each flow change. RESULTS: Study A: As gas flow increased (5, 8, 10 and 15 L/min) the median PEEP increased from 4.7 to 26.4 cm H(2)O (p<0.002). Median V(Te) decreased from 10.0 to 0.8 mL (p<0.001). PIP increased slightly from 30 cm H(2)O to 36 cm H(2)O at 15 L/min (p<0.005). Mask leak increased from 14% to 98% (p<0.001) because mask pressure increased. Study B: when PIP and PEEP were maintained there were no significant differences in V(Te) (p=0.42) or mask leak (p=0.51) with changing gas flow. CONCLUSION: During PPV increasing gas flow dramatically increased PEEP and mask leak and in consequence reduced V(Te). Gas flow should rarely be changed during T-piece resuscitation.

Low versus high gas flow rate for respiratory support of infants at birth: a manikin study.

BACKGROUND: Neonatal resuscitation guidelines do not specify the gas flow rate during mask ventilation. AIM: Investigating the effect of gas flow rates on pressures, volumes delivered and mask leak. METHODS: Flow 5 and 10 liters/min were tested. In study part 1, pressure ranges were measured when ventilating an intubated manikin with a Neopuff®. In study part 2, pediatric staff mask-ventilated a manikin (peak inflation pressure (PIP) 30 cm H(2)O, positive end expiratory pressure (PEEP) 5 cm H(2)O). We measured pressures, expired tidal volume (V(Te)) and mask leak. RESULTS: Study part 1:an intubated manikin was ventilated with flow 5 versus 10 liters/min: range in PEEP was 0.4-3.6 and 2-14 cm H(2)O, respectively, maximum PIP was 73 cm H(2)O with both flow rates. Study part 2: when mask ventilation was given with flow 5 versus 10 liters/min: leak decreased (24% (8-85) vs. 80% (34- 94); p < 0.0001), V(Te) increased (6.7 (5.1-7.8) vs. 4.7 (2.4-7.0) ml; p < 0.001), PEEP decreased (3.1 (0.8) vs. 3.7 (0.7) cm H(2)O; p < 0.001), PIP was similar (28.1 (2.7) vs. 28.0 (2.3) cm H(2)O; NS). Large leaks decreased V(Te) and PEEP during both flow rates, PIP only with flow 5 liters/min. CONCLUSION: A low flow rate during neonatal mask ventilation may be a good alternative approach in reducing mask leak, provided that inflation time and flow rate warrants set pressures. Only large leaks seem to influence delivered pressures and volumes. Before resuscitation guidelines are advised, more studies on gas flow rates are needed.

Leak and obstruction with mask ventilation during simulated neonatal resuscitation.

OBJECTIVES: To evaluate mask technique during simulated neonatal resuscitation and test the effectiveness of training in optimal mask handling. STUDY DESIGN: Seventy participants(consultants, registrars and nurses) from neonatal units were asked to administer positive pressure ventilation at a flow of 8 l/min and a frequency of 40-60/min to a modified leak free, term newborn manikin (lung compliance 0.5 ml/cm H(2)O) using a Neopuff T-piece device. Recordings were made (1) before training, (2) after training in mask handling and (3) 3 weeks later. Leak was calculated. Obstruction (tidal volume <60% of optimal tidal volume) and severe obstruction (<30% of optimal tidal volume) were calculated when leak was minimal. RESULTS: For the 70 participants, median (IQR) leak was 71% (32-95%) before training, 10% (5-37%) directly after training and 15% (4-33%) 3 weeks later (p<0.001). When leak was minimal, gas flow obstruction was observed before, directly after training and 3 weeks later in 46%, 42% and 37% of inflations, respectively. Severe obstruction did not occur. CONCLUSIONS: Mask ventilation during simulated neonatal resuscitation was often hampered by large leaks at the face mask. Moderate airway obstruction occurred frequently when effort was taken to minimise leak. Training in mask ventilation reduced mask leak but should also focus on preventing airway obstruction.