Maintaining normothermia immediately after birth in preterm infants <34 weeks' gestation: A systematic review and meta-analysis.

AIM: To evaluate delivery room (DR) interventions to prevent hypothermia and improve outcomes in preterm newborn infants <34 weeks' gestation. METHODS: Medline, Embase, CINAHL and CENTRAL were searched till 22nd July 2022. Randomized controlled trials (RCTs), non-RCTs and quality improvement studies were considered. A random effects meta-analysis was performed, and the certainty of evidence was evaluated using GRADE guidelines. RESULTS: DR temperature of ≥23 °C compared to standard care improved temperature outcomes without an increased risk of hyperthermia (low certainty), whereas radiant warmer in servo mode compared to manual mode decreased mean body temperature (MBT) (moderate certainty). Use of a plastic bag or wrap (PBW) improved normothermia (low certainty), but with an increased risk of hyperthermia (moderate certainty). Plastic cap improved normothermia (moderate certainty) and when combined with PBW improved MBT (low certainty). Use of a cloth cap decreased moderate hypothermia (low certainty). Though thermal mattress (TM) improved MBT, it increased risk of hyperthermia (low certainty). Heated-humidified gases (HHG) for resuscitation decreased the risk of moderate hypothermia and severe intraventricular hemorrhage (very low to low certainty). None of the interventions was shown to improve survival, but sample sizes were insufficient. CONCLUSIONS: DR temperature of ≥23 °C, radiant warmer in manual mode, use of a PBW and a head covering is suggested for preterm newborn infants <34 weeks' gestation. HHG and TM could be considered in addition to PBW provided resources allow, in settings where hypothermia incidence is high. Careful monitoring to avoid hyperthermia is needed.

Optimal human and system performance during neonatal resuscitation.

Performance in the delivery of care to sick neonates in need of resuscitation has long been defined primarily in terms of the extent of the knowledge possessed and hands-on skill demonstrated by physicians and other healthcare professionals. This definition of performance in neonatal resuscitation is limited by its focus solely on the human beings delivering care and a perceived set of the requisite skills to do so. This manuscript will expand the definition of performance to include all of the skill sets that humans must use to resuscitate newborns as well as the often complex systems in which those humans operate while delivering that care. It will also highlight how the principles of human factors and ergonomics can be used to enhance human and system performance during patient care. Finally, it will describe the role of simulation and debriefing in the assessment of human and system performance.

Assessing the tongue colour of newly born infants may help to predict the need for supplemental oxygen in the delivery room.

AIM: It takes several minutes for infants to become pink after birth. Preductal oxygen saturation (SpO2) measurements are used to guide the delivery of supplemental oxygen to newly born infants, but pulse oximetry is not available in many parts of the world. We explored whether the pinkness of an infant's tongue provided a useful indication that supplemental oxygen was required. METHODS: This was a prospective observational study of infants delivered by Caesarean section. Simultaneous recording of SpO2 and visual assessment of whether the tongue was pink or not was made at 1-7 and 10 min after birth. RESULTS: The 38 midwives and seven paediatric trainees carried out 271 paired assessments on 68 infants with a mean (SD) birthweight of 3214 (545) grams and gestational age of 38 (2) weeks. When the infant did not have a pink tongue, this predicted SpO2 of <70% with a sensitivity of 26% and a specificity of 96%. CONCLUSION: Tongue colour was a specific but insensitive sign that indicated when SpO2 was <70%. When the tongue is pink, it is likely that an infant has an SpO2 of more than 70% and does not require supplemental oxygen.

Comparison of heart rate and oxygen saturation measurements from Masimo and Nellcor pulse oximeters in newly born term infants.

AIM: To compare heart rate (HR) measurements from Masimo and Nellcor pulse oximeters (POs) against HR measured via a three lead electrocardiograph (ECG) (HRECG ). We also compared peripheral oxygen saturation (SpO2 ) measurements between Nellcor and Masimo oximeters. METHOD: Term infants born via elective caesarean section were studied. ECG leads were placed on the infant's chest and abdomen. Masimo and Nellcor PO sensors were randomly allocated to either foot. The monitors were placed on a trolley, and data from each monitor screen captured by a video camera. HR, SpO2 measurements and signal quality were extracted. Bland-Altman analysis was used to determine agreement between HR from the ECG and each oximeter, and between SpO2 from the oximeters. RESULTS: We studied 44 infants of whom 4 were resuscitated. More than 8000 pairs of observations were used for each comparison of HR and SpO2. The mean difference (±2SD) between HRECG and HRN ellcor was -0.8 (±11) beats per minute (bpm); between HRECG and HRM asimo was 0.2 (±9) bpm. The mean (±2SD) difference between SpO2Masimo and SpO2Nellcor was -3 (±15)%. The Nellcor PO measured 20% higher than the Masimo PO at SpO2 <70%. CONCLUSION: Both oximeters accurately measure HR. There was good agreement between SpO2 measurements when SpO2 ≥70%. At lower SpO2 , agreement was poorer.

Determining the best method of Nellcor pulse oximeter sensor application in neonates.

AIM: To identify the optimal sensor application method that gave the quickest display of accurate heart rate (HR) data using the Nellcor OxiMax N-600x pulse oximeter (PO). METHODS: Stable infants who were monitored with an electrocardiograph were included. Three sensor application techniques were studied: (i) sensor connected to cable, then applied to infant; (ii) sensor connected to cable, applied to investigator's finger, and then to infant; (iii) sensor applied to infant, then connected to cable. The order of techniques tested was randomized for each infant. Time taken to apply the PO sensor, to display data and to display accurate data (HR(PO) = HR(ECG) ± 3 bpm) were recorded using a stopwatch. RESULTS: Forty infants were studied [mean (SD) birthweight, 1455 (872) g; gestational age, 31 (4) weeks; post-menstrual age, 34 (4) weeks]. Method 3 acquired any data significantly faster than methods 1 (p = 0.013; CI, -9.6 to -3.0 sec) and 2 (p = 0.004; CI, -5.9 to -1.2 sec). Method 3 acquired accurate data significantly faster than method 1 (p = 0.016; CI, -9.4 to -1.0 sec), but not method 2 (p = 0.28). CONCLUSION: Applying the sensor to the infant before connecting it to the cable yields the fastest acquisition of accurate HR data from the Nellcor PO.

Changes in heart rate in the first minutes after birth.

The normal range of heart rate (HR) in the first minutes after birth has not been defined. Objective To describe the HR changes of healthy newborn infants in the delivery room (DR) detected by pulse oximetry. Study Design All inborn infants were eligible and included if a member of the research team attended the birth. Infants were excluded if they received any form of medical intervention in the DR including supplemental oxygen, or respiratory support. HR was measured using a pulse oximeter (PO) with the sensor applied to the right hand or wrist immediately after birth. PO data (oxygen saturation, HR and signal quality) were downloaded every 2 sec and analysed only when the signal had no alarm messages (low IQ signal, low perfusion, sensor off, ambient light). Results Data from 468 infants with 61 650 data points were included. Infants had a mean (range) gestational age of 38 (25-42) weeks and birth weight 2970 (625-5135) g. At 1 min the median (IQR) HR was 96 (65-127) beats per min (bpm) rising at 2 min and 5 min to 139 (110-166) bpm and 163 (146-175) bpm respectively. In preterm infants, the HR rose more slowly than term infants. Conclusions The median HR was <100 bpm at 1 min after birth. After 2 min it was uncommon to have a HR <100 bpm. In preterm infants and those born by caesarean section the HR rose more slowly than term vaginal births.

Oral continuous positive airway pressure (CPAP) following nasal injury in a preterm infant.

Non-invasive respiratory support is increasingly popular but is associated with complications including nasal trauma. The present report describes a novel method of oral continuous positive airway pressure (CPAP) delivery in an extremely premature infant with severe nasal septum erosion. The distal end of a cut down endotracheal tube was passed through a small hole made in the teat of a dummy (infant pacifier) and sutured in place. The dummy was secured in the infant's mouth and CPAP was delivered to the pharynx. The device was well tolerated and the infant was successfully managed using this technique for 48 days, avoiding endotracheal intubation and ventilation.

Assist control volume guarantee ventilation during surfactant administration.

OBJECTIVE: To measure changes in ventilator parameters in preterm infants receiving surfactant during assist control volume guarantee (AC/VG) ventilation. METHODS: 22 preterm infants (up to 32 weeks' gestation) receiving surfactant for respiratory distress syndrome were enrolled in a prospective study of ventilator parameters during AC/VG ventilation at a tertiary neonatal intensive care unit. Ventilator pressures, flow and tidal volume waveforms were recorded from the Dräger Babylog 8000 plus in real time, and compared to pre-surfactant measurements. RESULTS: Following surfactant administration, 21 of 22 babies experienced completely obstructed endotracheal gas flow. Peak inflation pressure (PIP) increased by a median (IQR) of 8 (4-10) cm H2O, and took 30-60 min to return to baseline. Inspired oxygen concentration was reduced from a median (IQR) of 39% (26%-44%) to 26% (21%-30%) in the first 5 min. The set maximum PIP (Pmax) limited the delivered PIP such that most babies received tidal volumes less than the target value (V(Ttarget)) immediately following surfactant delivery. Four infants, in a subgroup of 11 infants where Pmax was set to less than 10 cm H2O above baseline PIP, were still receiving <90% of V(Ttarget) 20 min post surfactant. CONCLUSIONS: When giving surfactant during AC/VG ventilation, complete obstruction is common. PIPs increased and remain elevated for 30-60 min. The Pmax setting may restrict tidal volume delivery.

Volume-guarantee ventilation: pressure may decrease during obstructed flow.

BACKGROUND: Two unexpected observations were made during ventilation with the Dräger Babylog 8000+ in volume-guarantee mode: (a) during complete obstruction to gas flow down the endotracheal tube (ETT), positive inspiratory pressure (PIP) was reduced to half way between the maximum inflating pressure and the positive end expiratory pressure (PEEP) even though the set expired tidal volume had not been achieved; (b) an external Dräger waveform monitor may stop displaying real-time waveforms when a tube-obstructed alarm is activated. OBJECTIVE: To investigate these phenomena using a test lung. METHOD: A 50 ml Dräger test lung was attached to the ventilation circuit of a Dräger Babylog 8000+. Partial obstruction to ETT flow was induced by compressing the tubing leading to the test lung, and complete obstruction was achieved by clamping. Recordings were made from the digital output of the ventilator at 125 Hz. RESULTS: When the ETT flow was completely obstructed during VG ventilation, a constant PIP was set midway between the set maximum and PEEP. This did not happen during partial obstruction. The external waveform monitor display froze when ETT flow was completely obstructed. CONCLUSIONS: During complete ETT obstruction, the PIP is set to a pressure midway between maximum PIP and PEEP even if this is less than the PIP used before the obstruction. Further research is needed to evaluate whether this reduction in PIP is associated with prolongation of precipitating events.

Oxygen saturation and heart rate during delivery room resuscitation of infants <30 weeks' gestation with air or 100% oxygen.

BACKGROUND: Because of concerns about harmful effects of 100% oxygen on newborn infants, air has started to be used for resuscitation in the delivery room. OBJECTIVE: To describe changes in preductal oxygen saturation (Spo(2)) and heart rate (HR) in the first 10 min after birth in very preterm infants initially resuscitated with 100% oxygen (OX(100)) or air (OX(21)). PATIENTS AND METHODS: In July 2006, policy changed from using 100% oxygen to air. Observations of Spo(2) and HR before and after the change were recorded whenever a member of the research team was available to attend the birth. RESULTS: There were 20 infants in the OX(100) group and 106 in the OX(21) group. In the OX(100) group, Spo(2) had risen to a median of 84% after 2 min and 94% by 5 min. In the OX(21) group, median Spo(2) was 31% at 2 min and 54% at 5 min. In the OX(21) group, 92% received supplemental oxygen at a median of 5 min; the Spo(2) rose to a median of 81% by 6 min. In the first 10 min after birth, 80% and 55% of infants in the OX(100) and OX(21) groups, respectively, had an Spo(2) > or =95%. Increases in HR over the first 10 min were very similar in the two groups. CONCLUSIONS: Most very preterm infants received supplemental oxygen if air was used for the initial resuscitation. In these infants, the use of backup 100% oxygen and titration against Spo(2) resulted in a similar course to "normal" term and preterm infants. Of the infants resuscitated with 100% oxygen, 80% had Spo(2) > or =95% during the first 10 min. The HR changes in the two groups were very similar.

A trial of spontaneous breathing to determine the readiness for extubation in very low birth weight infants: a prospective evaluation.

Extubation failure in premature infants is common. A spontaneous breathing trial (SBT) was prospectively evaluated to determine timing of extubation. Compared with historical controls, infants were extubated at significantly higher ventilator rates and airway pressures using the SBT. No differences in rates of bronchopulmonary dysplasia or duration of ventilation were seen.

Predicting successful extubation of very low birthweight infants.

OBJECTIVE: To determine the accuracy of three tests used to predict successful extubation of preterm infants. STUDY DESIGN: Mechanically ventilated infants with birth weight <1250 g and considered ready for extubation were changed to endotracheal continuous positive airway pressure (ET CPAP) for three minutes. Tidal volumes, minute ventilation (V e), heart rate, and oxygen saturation were recorded before and during ET CPAP. Three tests of extubation success were evaluated: (a) expired V e during ET CPAP; (b) ratio of V e during ET CPAP to V e during mechanical ventilation (V e ratio); (c) the spontaneous breathing test (SBT)-the infant passed this test if there was no hypoxia or bradycardia during ET CPAP. The clinical team were blinded to the results, and all infants were extubated. Extubation failure was defined as reintubation within 72 hours of extubation. RESULTS: Fifty infants were studied and extubated. Eleven (22%) were reintubated. The SBT was the most accurate of the three tests, with a sensitivity of 97% and specificity of 73% and a positive and negative predictive value for extubation success of 93% and 89% respectively. CONCLUSION: The SBT used just before extubation of infants <1250 g may reduce the number of extubation failures. Further studies are required to establish whether the SBT can be used as the primary determinant of an infant's readiness for extubation.

Neonatal resuscitation 1: a model to measure inspired and expired tidal volumes and assess leakage at the face mask.

BACKGROUND: Neonatal resuscitation is a common and important intervention, and adequate ventilation is the key to success. In the delivery room, positive pressure ventilation is given with manual ventilation devices using face masks. Mannequins are widely used to teach and practise this technique. During both simulated and real neonatal resuscitation, chest excursion is used to assess tidal volume delivery, and leakage from the mask is not measured. OBJECTIVE: To describe a system that allows measurement of mask leakage and estimation of tidal volume delivery. METHODS: Respiratory function monitors, a modified resuscitation mannequin, and a computer were used to measure leakage from the mask and to assess tidal volume delivery in a model of neonatal resuscitation. RESULTS: The volume of gas passing through a flow sensor was measured at the face mask. This was a good estimate of the tidal volume entering and leaving the lung in this model. Gas leakage between the mask and mannequin was also measured. This occurred principally during inflation, although gas leakage during deflation was seen when the total leakage was large. A volume of gas that distended the mask but did not enter the lung was also measured. CONCLUSION: This system can be used to assess the effectiveness of positive pressure ventilation given using a face mask during simulated neonatal resuscitation. It could be useful for teaching neonatal resuscitation and assessing ventilation through a face mask.

Obtaining pulse oximetry data in neonates: a randomised crossover study of sensor application techniques.

Pulse oximetry may be useful during neonatal resuscitation. A randomised crossover study was performed to determine the most efficient method of applying the sensor. Applying it to the infant before connecting to the oximeter resulted in quickest acquisition of accurate heart rate. This technique should be preferred during resuscitation.

Long versus short inspiratory times in neonates receiving mechanical ventilation.

BACKGROUND: When intermittent positive pressure ventilation (IPPV) was introduced in newborn infants with hypoxic respiratory failure from hyaline membrane disease (HMD), mortality was high and air leaks problematic. This barotrauma was caused by the high peak inspiratory pressures (PIP) required to oxygenate stiff lungs. The primary determinants of mean airway pressure (and thus oxygenation) on a conventional ventilator are the inspiratory time (IT), PIP, positive end expiratory pressure and gas flow rates. In the 1970s uncontrolled studies on a small number of infants demonstrated a benefit in reducing barotrauma using a long IT and slow rates. This strategy was subsequently widely adopted. Current neonatal ventilators have been designed to minimise lung injury but rates of bronchopulmonary dysplasia (BPD) remain high. It is therefore important that the inspiratory time causing least harm is used. OBJECTIVES: To determine in mechanically ventilated newborn infants whether the use of a long rather than a short IT reduces the rates of death, air leak and BPD. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Review Group (CNRG) was used. Searches of electronic and other databases were performed. These included MEDLINE (1966 - April 2004) and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2003). In order to detect trials that may not have been published, the abstracts of the Society for Pediatric Research, and the European Society for Pediatric Research were searched from 1998 - 2003. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials enrolling mechanically ventilated infants with or without respiratory pathology evaluating the use of long versus short IT (including randomised crossover studies with outcomes restricted to differences in oxygenation). DATA COLLECTION AND ANALYSIS: The standard method of the Cochrane Collaboration and its Neonatal Review Group were used. Two authors independently assessed eligibility, and the methodological quality of each trial, and extracted the data. The data were analysed using relative risk (RR) and risk difference (RD) and their 95% confidence intervals. A fixed effect model was used for meta-analyses. MAIN RESULTS: In five studies, recruiting a total of 694 infants, a long IT was associated with a significant increase in air leak [typical RR 1.56 (1.25, 1.94), RD 0.13 (0.07, 0.20), NNT 8 (5, 14)]. There was no significant difference in the incidence of BPD. Long IT was associated with an increase in mortality before hospital discharge that reached borderline statistical significance [typical RR 1.26 (1.00, 1.59), RD 0.07 (0.00, 0.13)]. REVIEWERS' CONCLUSIONS: Caution should be exercised in applying these results to modern neonatal intensive care, because the studies included in this review were conducted prior to the introduction of antenatal steroids, post natal surfactant and the use of synchronised modes of ventilatory support. Most of the participants had single pathology (HMD) and no studies examined the effects of IT on newborns ventilated for other reasons such as meconium aspiration and congenital heart disease (lungs with normal compliance). However, the increased rates of air leaks and deaths using long ITs are clinically important; thus, infants with poorly compliant lungs should be ventilated with a short IT.