Showing papers by "Simon Hannam published in 2012"
TL;DR: Low VT levels during VTV increase the WOB in ventilated infants born at term or near term, and the results suggest that a VT level of 6 ml/kg could be used to reduce the Wob.
Abstract: Objectives To determine the impact of different volume-targeted (VT) levels during volume-targeted ventilation (VTV) on the work of breathing (WOB) of infants born at or near term and to investigate whether a level of VT reduced the WOB below that experienced on respiratory support without VT. Design Prospective crossover study. Patients Sixteen infants, median gestational age of 38 (range 34–41) weeks, birth weight of 3.1 (range 1.5–4.1) kg and postnatal age of 5 (range 2–17) days were studied. The infants were receiving time-cycled, pressure-limited ventilation in a continuous mandatory or in a triggered mode. Interventions The infants were studied first without VT (baseline) and then at VT levels of 4, 5 and 6 ml/kg delivered in a random order. After each VT level, the infants were returned to baseline. Main outcome measure The WOB was assessed by measuring the transdiaphragmatic pressure-time product (PTPdi). Results One infant became apnoeic at VT of 6 ml/kg. At a VT level of 4 ml/kg, four infants were making such vigorous respiratory efforts that no inflations were delivered. The median PTPdi was higher at a VT level of 4 ml/kg than at 5 ml/kg (p Conclusion Low VT levels (4 ml/kg) during VTV increase the WOB in ventilated infants born at term or near term. The results suggest that a VT level of 6 ml/kg could be used to reduce the WOB.
16 citations
TL;DR: No significant differences were found between weaning by PSV and ACV when similar inflation times were used, and there were no significant differences in the median PTPdi, TAA and Pimax results at any time point.
Abstract: Objectives To determine if the work of breathing was lower, respiratory muscle strength greater, but the degree of asynchrony higher during weaning by assist control ventilation (ACV) rather than pressure support ventilation (PSV) and if any differences were associated with a shorter duration of weaning. Design Randomised trial Setting Tertiary neonatal unit Patients Thirty-six infants, median gestational age 29 (range 24 to 39) weeks Intervention Weaning by either ACV or PSV. Main outcome measures At baseline, 24 hours after entering the study and immediately prior to extubation, the work of breathing (PTPdi), thoracoabdominal asynchrony (TAA) and respiratory muscle strength (Pimax) were assessed and weaning duration recorded. Results There were no significant differences in the median PTPdi, TAA and Pimax results at any time point. The inflation times during ACV and PSV were similar. The median duration of weaning was 34 (range 7–100) hours in the ACV group and 27 (range 10–169) hours in the PSV group (p=0.88). Conclusion No significant differences were found between weaning by PSV and ACV when similar inflation times were used.
14 citations
TL;DR: A case of a woman with bipolar disorder taking olanzapine during pregnancy, whose baby developed neonatal refractory hypoglycaemia due to hyperinsulinism within a few hours of birth.
Abstract: Information regarding the safety of olanzapine and other antipsychotics during pregnancy is limited. Due to the ethical difficulties in conducting randomized controlled trials in pregnant women, the best available data are from nonrandomized observational studies and case reports [Howard et al. 2004]. We present a case of a woman with bipolar disorder taking olanzapine during pregnancy, whose baby developed neonatal refractory hypoglycaemia due to hyperinsulinism within a few hours of birth.
8 citations
TL;DR: There was considerable variation in respiratory support practices for term-born infants, particularly between different levels of neonatal care provision.
Abstract: Infants born at term requiring mechanical ventilation suffer significant mortality and morbidity, yet few studies have tried to identify the optimum respiratory support for such infants. We, therefore, hypothesised that practice would vary, particularly between different levels of neonatal care provision. The lead clinicians of all 212 UK neonatal units were asked to complete an electronic web-based survey regarding respiratory support practices for term-born infants. Survey questions included the level of neonatal care provided, number of term-born infants ventilated per annum, initial and rescue ventilation modes and whether surfactant or inhaled nitric oxide (NO) were used. The overall response rate was 82 %. A greater proportion of neonatal intensive care units (NICUs) compared to local neonatal units (LNUs) stated that they used volume-targeting, particularly for infants with RDS (p = 0.0006) or congenital pneumonia (p = 0.0005). High-frequency oscillatory ventilation was stated as initial mode by a greater proportion of NICUs compared to LNUs and special care units (SCUs), particularly for respiratory distress syndrome (p < 0.0001) or persistent pulmonary hypertension of the newborn (p < 0.001). Continuous mandatory ventilation was stated to be the rescue mode by a greater proportion of LNUs/SCUs compared to NICUs (p < 0.0001). Surfactant was stated to be most commonly given for respiratory distress syndrome (79 % of units) and MAS (61 % of units); surfactant use was lowest in SCUs (p < 0.0001); inhaled NO was infrequently used by LNUs and SCUs. Conclusions There was considerable variation in respiratory support practices for term-born infants, particularly between different levels of neonatal care provision.
5 citations
TL;DR: Testing the hypothesis that infants of mothers who had smoked antenatally compared to infants of non-smoking mothers would have a poorer ventilatory response to hypoxia suggests intrauterine exposure to tobacco smoking may result in impairment of the infant peripheral chemoreceptor response.
Abstract: Aims Infants of mothers who smoked during pregnancy have an increased risk of sudden infant death; a possible explanation is that such infants have neurodevelopmental abnormalities of ventilatory control. Our aim was to test the hypothesis that infants of mothers who had smoked antenatally compared to infants of non-smoking mothers would have a poorer ventilatory response to hypoxia. Methods Infants were recruited before maternity unit discharge and assigned to one of two groups based on maternal smoking history. A pneumotachograph and face mask were placed over the infant9s mouth and nose. During quiet sleep, the infants were switched from breathing room air to 15% oxygen (hypoxic challenge), which was maintained for five minutes unless the oxygen saturation level fell below 85%. Changes in oxygen saturation, heart rate, respiratory rate, tidal and minute volume and end tidal CO2 (ETCO2) were assessed. Results Ten infants of smoking mothers (median gestational age of 39 (36-41) weeks) and 10 infants of non smoking mothers (39 (37-42) weeks) were studied. The median birth weight of the infants of the smoking mothers was lower than that of infants of the non-smoking mothers (2450 (1924-3790) grams versus 3299 (2560-4320) grams, p=0.04). The infants were studied at similar postnatal ages (median 30 (10-120) versus 32 (10-100) hours), p=0.7. The two groups had comparable baseline tidal breathing, oxygen saturation, heart rate and ETCO2 levels. In response to the hypoxic challenge, the two groups had similar falls in their oxygen saturation and increases in heart rate. There was a biphasic response in minute ventilation to the hypoxic challenge. There was no significant differences in the initial percentage increase in minute ventilation between the two groups (median 29% (range 17-40) versus 23% (2-35), p=0.23, but the subsequent percentage decrease in minute volume in the infants of the smoking mothers was greater than that of the infants of the non-smoking mothers (median 32 % (range 0-99) versus 0%(−20-32)), p=0.03. Conclusion These results suggest intrauterine exposure to tobacco smoking may result in impairment of the infant peripheral chemoreceptor response.
2 citations
Journal Article•
TL;DR: In this article, the authors tested the hypothesis that infants of substance abusing mothers (SA) and of smoking mothers (SM) compared to infants of non substance abusing, non-smoking mothers (controls) would have a poorer ventilatory response to hypercarbia.
Abstract: Infants of smoking and substance abusing mothers have an increased risk of sudden infant death. A possible explanation for the association is that such infants have neurodevelopmental abnormalities which adversely affect the control of ventilation. Aims : To test the hypothesis that infants of substance abusing mothers (SA) and of smoking mothers (SM) compared to infants of non substance abusing, non-smoking mothers (controls) would have a poorer ventilatory response to hypercarbia. Methods : Infants were assessed before maternity/neonatal unit discharge. Respiratory flow (and tidal volume) was measured using a pneumotachograph inserted into a face mask placed over the infant9s mouth and nose. The ventilatory responses to three levels of inspired carbon dioxide (baseline = 0%, 2% and 4% CO 2 ) were assessed. Results : 8 SA, 15 SM and 15 control infants were assessed. The birth weight of the controls was higher than the SA and SM infants (p=0.01). At baseline SA infants had a higher respiratory rate (p=0.03) and minute volume (p=0.049) compared to controls and SM infants (Table). Both the SA and SM infants had a lower respiratory response to 2% (p=0.02) and 4% (p=0.004) CO 2 Conclusion : These results are consistent with infants of smoking and substance abusing mothers having a dampened ventilatory response to hypercarbia.