Introducing a novel respiratory function monitor for neonatal resuscitation training.

Background: A respiratory function monitor (RFM) gives immediate feedback, allowing clinicians to adjust face mask ventilation to correct leak or inappropriate tidal volumes. We audited the satisfaction of clinicians with a neonatal resuscitation training package, incorporating a novel RFM. Methods: This was a mixed-methods study conducted at The Royal Women's Hospital, Melbourne, Australia. Clinicians were approached to complete a neonatal resuscitation training session. Participants watched a training video, then provided ventilation to term and preterm manikins first without, and then with, the RFM. Clinicians completed a survey after the session and undertook a follow-up session three months later. The primary outcome was participant satisfaction with the RFM. Secondary outcomes included participants' self-assessment of face mask leak and tidal volumes when using the RFM. Results: Fifty clinicians completed both the initial and follow-up session. Participants reported high levels of satisfaction with the RFM for both term and preterm manikins: on a scale from 0, meaning "not at all", and 100, meaning "yes, for all resuscitations", the median response (interquartile range, IQR) was 82 (74-94) vs 81.5 (69-94.5). Levels of satisfaction were similar for less experienced and more experienced clinicians: median (IQR) 83 (77-93) vs 81 (71.5-95) respectively. When using the monitor, clinicians accurately self-assessed that they achieved leak below 30% and tidal volumes within the target range at least 80% of the time. Conclusion: Clinicians of all experience levels had a high level of satisfaction with a training package including a novel RFM.

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.

Maintaining normal temperature immediately after birth in late preterm and term infants: A systematic review and meta-analysis.

AIM: Prevention of hypothermia after birth is a global problem in late preterm and term neonates. The aim of this systematic review and meta-analysis was to evaluate delivery room strategies to maintain normothermia and improve survival in late preterm and term neonates (≥34 weeks' gestation). METHODS: Medline, Embase, CINAHL, CENTRAL and international clinical trial registries were searched. Randomized controlled trials (RCTs), quasi-RCTs and observational studies were eligible for inclusion. Risk of bias for each study and GRADE certainty of evidence for each outcome were assessed. RESULTS: 25 RCTs and 10 non-RCTs were included. Room temperature of 23 °C compared to 20 °C improved normothermia [Risk Ratio (RR), 95% Confidence Interval (CI): 1.26, 1.11-1.42)] and body temperature [Mean Difference (MD), 95% CI: 0.30 °C, 0.23-0.37 °C), and decreased moderate hypothermia (RR, 95% CI: 0.26, 0.16-0.42). Skin to skin care (SSC) compared to no SSC increased body temperature (MD, 95% CI: 0.32, 0.10-0.52), reduced hypoglycemia (RR, 95% CI: 0.16, 0.05-0.53) and hospital admission (RR, 95% CI: 0.34, 0.14-0.83). Though plastic bag or wrap (PBW) alone or when combined with SSC compared to SSC alone improved temperatures, the risk-benefit balance is uncertain. Clinical benefit or harm could not be excluded for the primary outcome of survival for any of the interventions. Certainty of evidence was low to very low for all outcomes. CONCLUSIONS: Room temperature of 23 °C and SSC soon after birth may prevent hypothermia in late preterm and term neonates. Though PBW may be an effective adjunct intervention, the risk-benefit balance needs further investigation.

Monitoring heart rate in the delivery room.

Resuscitation algorithms and guidelines highlight the importance of heart rate (HR) in determining interventions and assessing their effect. However, the actual HR values used are historical based upon normal physiology, and HR at birth may be affected by mode of delivery and timing of cord clamping as well as respiratory status and condition at delivery. Furthermore, the most accurate and effective ways to assess and monitor HR in the newborn infant are only now becoming established. This article examines the importance of HR values and the most widely used methods of estimation as well as some newer modalities which are being developed.

The effect of skin-to-skin care on cerebral oxygenation during nasogastric feeding of preterm infants.

AIM: To describe cerebral oxygenation during gavage feeding of preterm infants during incubator and skin-to-skin care. METHODS: Further analysis of data from two crossover studies comparing cerebral oxygenation, heart rate and oxygen saturation during skin-to-skin care with incubator care. Data were analysed in three epochs; 10 minutes prefeed, during-feed and 10 minutes postfeed. Measurements from infants fed during incubator care were compared with those obtained during skin-to-skin care. RESULTS: In 39 infants [median (IQR) 27.8 (26.1-30.0) weeks' gestation], there was no difference in cerebral oxygenation between pre-, during- and postfeed. Heart rate increased by three beats per minute postfeed compared with during-feed. Twenty infants received two gavage feeds, one feed in the incubator and another during skin-to-skin care. There was no difference in cerebral oxygenation and heart rate; peripheral oxygen saturation decreased by 3% during feeding whilst skin-to-skin care compared with feeding in the incubator. CONCLUSION: Cerebral oxygenation remained stable before, during and after gavage feeding in an incubator and during skin-to-skin care. The small decrease in oxygen saturation whilst receiving gavage feeding during skin-to-skin care is unlikely to be clinically important, providing reassurance that preterm infants maintain physiological stability during skin-to-skin care.

Social status and energy intake: a randomized controlled experiment.

While the inverse association between socioeconomic status (SES) and obesity in high gross domestic product countries is well established using observational data, the extent to which the association is due to a true causal effect of SES and, if so, the mechanisms of this effect remain incompletely known. To assess the influence of social status on obesity via energy intake, we randomized individuals to a higher or lower social status and observed subsequent energy intake. College students between the ages of 18 and 25 were randomized to social status and were operationalized as being a leader or follower in a partner activity as purportedly determined by a (bogus) test of leadership ability. Investigators were blinded to treatment assignment. Immediately after being told their leadership assignment, paired participants were provided with platters of food. Energy intake was objectively measured in kilocalories (kcal) consumed, and paired t-tests were used to test for significant differences in intake between leaders and followers. A total of 60 participants were included in the final analysis (males = 28, females = 32). Overall, no difference in energy intake was observed between leaders and followers, consuming an average of 575.3 and 579.8 kcal, respectively (diff = 4.5 kcal, P = 0.94). The null hypothesis of no effect of social status, operationalized as assignment to a leadership position in a small-group activity, on energy intake was not rejected.

Extended calorie restriction suppresses overall and specific food cravings: a systematic review and a meta-analysis.

BACKGROUND: Multiple studies have concluded that calorie restriction for at least 12 weeks is associated with reduced food cravings, while others have shown that calorie restriction may increase food cravings. We addressed this ambiguity in a systematic review and meta-analysis. METHODS: We searched for studies conducted on subjects with obesity, implemented calorie restriction for at least 12 weeks and measured food cravings pre-intervention and post-intervention. Our final eight studies mostly used the Food Craving Inventory. Other comparable methods were converted to a similar scale. We used the duration ≥12 weeks, but closest to 16 weeks for studies with multiple follow-ups and performed DerSimonian-Laird random-effects meta-analyses using the 'metafor' package in r software. RESULTS: Despite heterogeneity across studies, we observed reductions in pooled effects for overall food cravings (-0.246 [-0.490, -0.001]) as well as cravings for sweet (-0.410 [-0.626, -0.194]), high-fat (-0.190 [-0.343, -0.037]), starchy (-0.288 [-0.517, -0.058]) and fast food (-0.340 [-0.633, -0.048]) in the meta-analysis. Baseline body weight, type of intervention, duration, sample size and percentage of female subjects explained the heterogeneity. CONCLUSIONS: Calorie restriction is associated with reduced food cravings supporting a de-conditioning model of craving reductions. Our findings should ease the minds of clinicians concerned about increased cravings in patients undergoing calorie restriction interventions.

Changes in pediatric waist circumference percentiles despite reported pediatric weight stabilization in the United States.

BACKGROUND: Obesity is a global health concern but the United States has reported a leveling in obesity rates in the pediatric population. OBJECTIVE: To provide updated waist circumference (WC) percentile values, identify differences across time and discuss differences within the context of reported weight stabilization in a nationally representative sample of American children. METHODS: Percentiles for WC in self-identified African Americans (AA), European Americans (EA) and Mexican Americans (MA) were obtained from 2009-2014 National Health and Nutrition Examination Survey data (NHANES2014). Descriptive trends across time in 10th, 25th, 50th, 75th and 90th percentile WC distributions were identified by comparing NHANES2012 with previously reported NHANESIII (1988-1994). RESULTS: WC increased in a monotonic fashion in AA, EA and MA boys and girls. When compared with NHANESIII data, a clear left shift of percentile categories was observed such that values that used to be in the 90th percentile are now in the 85th percentile. Differences in WC were observed in EA and MA boys during a reported period of weight stabilization. CONCLUSION AND RELEVANCE: WC has changed in the US pediatric population across time, even during times of reported weight stabilization, particularly among children of diverse racial/ethnic backgrounds.

Rigorous control conditions diminish treatment effects in weight loss-randomized controlled trials.

BACKGROUND: It has not been established whether control conditions with large weight losses (WLs) diminish expected treatment effects in WL or prevention of weight gain (PWG)-randomized controlled trials (RCTs). SUBJECTS/METHODS: We performed a meta-analysis of 239 WL/PWG RCTs that include a control group and at least one treatment group. A maximum likelihood meta-analysis framework was used to model and understand the relationship between treatment effects and control group outcomes. RESULTS: Under the informed model, an increase in control group WL of 1 kg corresponds with an expected shrinkage of the treatment effect by 0.309 kg (95% confidence interval (-0.480, -0.138), P=0.00081); this result is robust against violations of the model assumptions. CONCLUSIONS: We find that control conditions with large WLs diminish expected treatment effects. Our investigation may be helpful to clinicians as they design future WL/PWG studies.

Predicting adult weight change in the real world: a systematic review and meta-analysis accounting for compensatory changes in energy intake or expenditure.

BACKGROUND: Public health and clinical interventions for obesity in free-living adults may be diminished by individual compensation for the intervention. Approaches to predict weight outcomes do not account for all mechanisms of compensation, so they are not well suited to predict outcomes in free-living adults. Our objective was to quantify the range of compensation in energy intake or expenditure observed in human randomized controlled trials (RCTs). METHODS: We searched multiple databases (PubMed, CINAHL, SCOPUS, Cochrane, ProQuest, PsycInfo) up to 1 August 2012 for RCTs evaluating the effect of dietary and/or physical activity interventions on body weight/composition. INCLUSION CRITERIA: subjects per treatment arm ≥5; ≥1 week intervention; a reported outcome of body weight/body composition; the intervention was either a prescribed amount of over- or underfeeding and/or supervised or monitored physical activity was prescribed; ≥80% compliance; and an objective method was used to verify compliance with the intervention (for example, observation and electronic monitoring). Data were independently extracted and analyzed by multiple reviewers with consensus reached by discussion. We compared observed weight change with predicted weight change using two models that predict weight change accounting only for metabolic compensation. FINDINGS: Twenty-eight studies met inclusion criteria. Overfeeding studies indicate 96% less weight gain than expected if no compensation occurred. Dietary restriction and exercise studies may result in up to 12-44% and 55-64% less weight loss than expected, respectively, under an assumption of no behavioral compensation. INTERPRETATION: Compensation is substantial even in high-compliance conditions, resulting in far less weight change than would be expected. The simple algorithm we report allows for more realistic predictions of intervention effects in free-living populations by accounting for the significant compensation that occurs.

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.

Are high flow nasal cannulae noisier than bubble CPAP for preterm infants?

BACKGROUND: Noise exposure in the neonatal intensive care unit is believed to be a risk factor for hearing loss in preterm neonates. Continuous positive airway pressure (CPAP) devices exceed recommended noise levels. High flow nasal cannulae (HFNC) are an increasingly popular alternative to CPAP for treating preterm infants, but there are no in vivo studies assessing noise production by HFNC. OBJECTIVE: To study whether HFNC are noisier than bubble CPAP (BCPAP) for preterm infants. METHODS: An observational study of preterm infants receiving HFNC or BCPAP. Noise levels within the external auditory meatus (EAM) were measured using a microphone probe tube connected to a calibrated digital dosimeter. Noise was measured across a range of frequencies and reported as decibels A-weighted (dBA). RESULTS: A total of 21 HFNC and 13 BCPAP noise measurements were performed in 21 infants. HFNC gas flows were 2-5 L/min, and BCPAP gas flows were 6-10 L/min with set pressures of 5-7 cm of water. There was no evidence of a difference in average noise levels measured at the EAM: mean difference (95% CI) of -1.6 (-4.0 to 0.9) dBA for HFNC compared to BCPAP. At low frequency (500 Hz), HFNC was mean (95% CI) 3.0 (0.3 to 5.7) dBA quieter than BCPAP. Noise increased with increasing BCPAP gas flow (p=0.007), but not with increasing set pressure. There was a trend to noise increasing with increasing HFNC gas flows. CONCLUSIONS: At the gas flows studied, HFNC are not noisier than BCPAP for preterm infants.

Self-inflating bags versus T-piece resuscitator to deliver sustained inflations in a preterm lamb model.

OBJECTIVE: In neonatal resuscitation, the use of a sustained inflation (SI) may facilitate lung aeration. Previous studies comparing different resuscitation devices have shown that one model of self-inflating bag (SIB) could not deliver an SI. We aimed to compare the delivery of an SI using four SIBs with that of a T-piece. STUDY DESIGN: In intubated preterm lambs, we compared four models of SIB fitted with a positive end expiratory pressure (PEEP) valve to a T-piece using a gas flow of 8 L/min. Four operators aimed to deliver three SIs of 20 cm H2O for 30 s. The study was repeated with the PEEP valve removed and again with no flow. We measured duration of SI, average inflation pressure (IP) and analysed the shape of the pressure curves. RESULTS: 204 combinations were analysed. Mean (SD) duration of SI was Ambu 6(2)s, Laerdal 14(8)s, Parker Healthcare 5(1)s, Mayo Healthcare 33(2)s and T-piece 33(1)s. Mean (SD) average IP was Ambu 17(3)cm H2O, Laerdal 17(3)cm H2O, Parker Healthcare 12(5)cm H2O, Mayo Healthcare 21(2)cm H2O and T-piece 20(0)cm H2O. Duration of SI and average IP was significantly different between SIBs (all p<0.001). The findings were substantially unchanged when PEEP valve and flow were removed (all p>0.05). Only the Mayo system delivered SIs with duration and average IP not significantly different from the T-piece (p>0.05). CONCLUSIONS: The performance of the four SIBs tested varied considerably. Some are able to deliver an SI even in the absence of gas flow. This may be useful in a resource-limited setting with no gas supply.

The precision and accuracy of Nellcor and Masimo oximeters at low oxygen saturations (70%) in newborn lambs.

BACKGROUND: Administration of oxygen in the delivery room is informed by oxygen saturation (SpO2). An oxygen saturation range of 60%-70% is the threshold for administering oxygen in the first minutes after birth. The accuracy of newer generation oximeters to measure SpO2 has not been compared against the 'gold standard', direct arterial blood oxygen saturation (SaO2) when SaO2 is low. The aim of this study was to determine the accuracy and precision of Nellcor and Masimo oximeters to measure SpO2 when SaO2 <70%. METHOD: Prospective observational study in ventilated anaesthetised newborn lambs with an indwelling carotid artery catheter. Ventilation was adjusted to achieve hypoxaemia. Nellcor (Oxi-Max 600 with Max-N sensor) and Masimo (Rad 4 with low noise optical probe (LNOP) sensor) sensors were applied to the right forelimb (preductal). An arterial blood sample was collected at 1-5 min intervals when the animal was hypoxic. The displayed SpO2 was recorded. We used Bland-Altman analysis to determine precision and accuracy of each oximeter when SaO2 <70%. RESULTS: 17 lambs were studied, 165 measurements were obtained, 123 were SaO2 <70%. The mean difference (±1.96 SD) Nellcor SpO2-SaO2 when SaO2 <70% was 17% (-12% to 46%). The mean difference (±1.96 SD) Masimo SpO2-SaO2 when SaO2 <70% was 13% (-19% to 45%). CONCLUSIONS: At SaO2<70%, both monitors overestimated oxygen saturation (SpO2) compared with the gold standard. Both oximeters were equally inaccurate when SaO2 was low.

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.

Effects of non-synchronised nasal intermittent positive pressure ventilation on spontaneous breathing in preterm infants.

BACKGROUND: Nasal intermittent positive pressure ventilation (NIPPV) may be beneficial but the mechanisms of action are undetermined. AIM: To investigate the effects of non-synchronised NIPPV on spontaneous breathing in premature infants. METHODS: 10 infants receiving ventilator generated non-synchronised NIPPV were studied for 30 min. Delivered pressure was measured at the nose; respiration was recorded using respiratory inductance plethysmography. Oxygen saturation, carbon dioxide, heart rate, inspired oxygen and video images were recorded. RESULTS: Median gestational age, birth weight, age and study weight were 25(+3) weeks, 797 g, 24 days and 1076 g. When the NIPPV pressure peak commenced during spontaneous inspiration the inspiratory time increased by 21% (p=0.002), relative tidal volume increased by 15% (p=0.01) and expiratory time was unchanged. When the NIPPV pressure peak commenced during spontaneous expiration the expiratory time increased by 13% (p=0.04). NIPPV pressures delivered during apnoea (range 8-28 cm H(2)O) produced chest inflation 5% of the time, resulting in small tidal volumes (26.7% of spontaneous breath size) but reduced oxygen desaturation. NIPPV pressure peaks occurred throughout spontaneous respiration proportional to the inspiratory: expiratory ratio. CONCLUSION: NIPPV pressure peaks only resulted in a small increase in relative tidal volumes when delivered during spontaneous inspiration. During apnoea pressure peaks occasionally resulted in chest inflation, which ameliorated oxygen desaturations. Infants did not become entrained with the NIPPV pressure changes. Synchronising every rise in applied pressure with spontaneous inspiration may increase the effectiveness of NIPPV and warrants investigation.

A randomised placebo-controlled double-blind trial to evaluate lipid-lowering pharmacotherapy on proteolysis and inflammation in abdominal aortic aneurysms.

OBJECTIVES: Modulation of abdominal aortic aneurysm (AAA) expansion by HMG-CoA reductase inhibitors (statins) might be linked to reducing IL-6 and MMP-9, which may be consequent on reducing plasma cholesterol. Ezetimibe is a novel cholesterol absorption inhibitor used in combination with statins. This pilot study compared the biological effects of ezetimibe combination therapy with simvastatin alone on parameters relevant to aneurysm expansion including cytokines and proteolytic enzymes. DESIGN: Randomised placebo-controlled double-blind trial. MATERIALS & METHODS: Eighteen patients scheduled for elective open AAA repair were randomised to simvastatin 40 mg plus ezetimibe 10 mg (n = 9), or simvastatin 40 mg plus placebo (n = 9), for 32.5 days (IQR 28-50.5) until the day of surgery. Total concentrations of TNF-α, IL-1ß, IL-6, IL-8, IL-10, MMPs-1, -2, -3, -8, -9, -12, -13, TIMP-1 and -2 were measured in plasma, aortic wall homogenates and tissue culture explants. RESULTS: Two patients in the placebo arm did not undergo open repair precluding aortic samples. Ezetimibe was associated with a significant reduction in aortic wall MMP-9 (p = 0.02) and aortic wall IL-6 (p = 0.02), associated with a reduction in plasma lipids. CONCLUSIONS: These results suggest that ezetimibe combination therapy reduces aortic wall proteolysis and inflammation, key processes that drive AAA expansion. A larger RCT is justified focussing on aneurysm growth rates in small AAA.

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.