Kim Schilleman

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 H2O) 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.

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.

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.

Variability in the Assessment of ‘Adequate’ Chest Excursion during Simulated Neonatal Resuscitation

Background: International neonatal resuscitation guidelines recommend assessing chest excursion when the heart rate is not improving. However, the accuracy in assessing ‘adequate’ chest excursion lacks objectivity. Aim: It was the aim of this study to test the accuracy in the assessment of ‘adequate’ chest excursion by measuring intra- and inter-observer variability of participants during simulated neonatal resuscitation. Methods: Thirty-seven staff members (8 neonatologists, 8 registrars, 21 nurses) of the Neonatal Intensive Care Unit, Leiden University Medical Center, Leiden, The Netherlands, ventilated 2 different intubated, leak-free manikins at 2 attempts, each with a different compliance. Blinded to the manometer, participants could change the peak inflation pressure until chest movement was adequate according to their perception. Inflating pressures were recorded. Results: According to the participants, a median (interquartile range) pressure of 18 cm H2O (16–22) at the first and 18 cm H2O (16–25) at the second attempt were needed to reach adequate chest excursion in the Laerdal manikin. The HAL manikin needed 26 cm H2O (19–31) and 24 cm H2O (22–33), respectively. The inter-observer coefficient of variance was 30% with the Laerdal manikin at both attempts, and 35 and 40% with the HAL manikin, respectively. The intra-observer coefficient of variance was 15% (8–23) with the Laerdal and 13% (9–20) with the HAL manikin. In both manikins and attempts, no significant differences in pressures and variances of pressures between the 3 groups were found. Conclusion: ‘Adequate’ chest excursion is a subjective parameter for guidance of appropriate ventilation during neonatal resuscitation.

Auditing documentation on delivery room management using video and physiological recordings

Objective Neonatal resuscitation is often retrospectively documented, which can lead to inaccuracy and incomplete recording of delivery room management. In this study, we assessed the accuracy and completeness of neonatal resuscitation documentation in our neonatal intensive care unit. Methods Recordings of physiological parameters and video data were performed in the delivery room and used to deduct the clinical condition of the infant, the interventions done and their effect on the infants condition. The data from the recordings were compared with the documentation on neonatal stabilisation in the medical records (paper or digital). Results Recordings of 54 infants were compared with the documentation in their medical records. In 93% of the medical records delivery room management was documented. The clinical condition of the infant at birth was documented in 76% and 1 min Apgar scores in 98%. Respiratory support was correctly documented in 83%, heart rate in 37% and oxygen saturation in 13%. In 57% use of supplemental oxygen and its indication were correctly reported. Seven infants were intubated and this was correctly documented in 57%. Apgar scores were compared between the recordings and the medical records. At 1 min, 5 min and 10 min after birth the Apgar score, given by the researcher using the recordings, was similar to the scores in the medical records in 33%, 44% and 53%, respectively. Conclusions Accurate and complete documentation of neonatal resuscitation continues to be a challenge. Recordings of physiological parameters and video imaging can improve documentation by providing detailed information.

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.

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.

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 H2O, positive end expiratory pressure (PEEP) 5 cm H2O). We measured pressures, expired tidal volume (VTe) 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 H2O, respectively, maximum PIP was 73 cm H2O 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), VTe 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 H2O; p < 0.001), PIP was similar (28.1 (2.7) vs. 28.0 (2.3) cm H2O; NS). Large leaks decreased VTe 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.

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.