David A Todd

Role of ureaplasma urealyticum in lung disease of prematurity.

AIM To examine the role of Ureaplasma urealyticum colonisation or infection in neonatal lung disease. METHODS Endotracheal aspirates from ventilated infants less than 28 weeks of gestation were cultured for U urealyticum and outcomes compared in infants with positive and negative cultures. RESULTS U urealyticum was isolated from aspirates of 39 of 143 (27%) infants. Respiratory distress syndrome (RDS) occurred significantly less often in colonised, than in non-colonised infants (p=0.002). Multivariate logistic regression analysis showed that in singleton infants, ureaplasma colonisation was the only independent (negative) predictor of RDS (OR 0.36; p=0.02). Both gestational age (OR 0.46; p=0.006) and isolation of U urealyticum (OR 3.0; p=0.05) were independent predictors of chronic lung disease (CLD), as defined by requirement for supplemental oxygen at 36 weeks of gestational age. Multiple gestation was also a major independent predictor of RDS and CLD. CONCLUSIONS Colonisation or infection with ureaplasma apparently protects premature infants against the development of RDS (suggesting intrauterine infection). However, in singleton infants, it predisposes to development of CLD, independently of gestational age. Treatment of affected infants after birth is unlikely to significantly improve the outcome and methods are required to identify and treat the women with intrauterine ureaplasmal infection, before preterm delivery occurs.

Methods of weaning preterm babies <30 weeks gestation off CPAP: a multicentre randomised controlled trial

Background Controversy exists whether different continuous positive airway pressure (CPAP) weaning methods influence time to wean off CPAP, CPAP duration, oxygen duration, Bronchopulmonary Dysplasia (BPD) or length of admission. Aims In a multicentre randomised controlled trial, the authors have primarily compared CPAP weaning methods impact on time to wean off CPAP and CPAP duration and secondarily their effect on oxygen duration, BPD and time of admission. Methods Between April 2006 and October 2009, 177 infants <30 weeks gestational age (GA) who fulfilled stability criteria on CPAP were randomised to one of the three CPAP weaning methods (M). M1: Taken ‘OFF’ CPAP with the view to stay ‘OFF’. m2: Cycled on and off CPAP with incremental time ‘OFF’. M3: As with m2, cycled on and off CPAP but during ‘OFF’ periods were supported by 2 mm nasal cannula at a flow of 0.5 l/min. Results Based on intention to treat analysis, there was no significant difference in mean GA or birthweight between the groups (27.1±1.4, 26.9±1.6 and 27.3±1.5 (weeks±1SD) and 988±247, 987±249 and 1015±257 (grams±1SD), respectively). Primary outcomes showed M1 produced a significantly shorter time to wean from CPAP (11.3±0.8, 16.8±1.0, 19.4±1.3 (days±1SE) p<0.0001, respectively) and CPAP duration (24.4±0.1, 38.6±0.1, 30.5±0.1 (days±1SE) p<0.0001, respectively). All the secondary outcomes were significantly shorter with M1, (oxygen duration: 24.1±1.5, 45.8±2.2, 34.1±2.0 (days±1SE) p<0.0001, BPD: 7/56 (12.5%), 29/69 (42%), 10/52 (19%) p=0.011 and length of admission: 58.5±0.1, 73.8±0.1 69.5±0.1 (days±1SE) p<0.0001, respectively). Conclusion Method 1 significantly shortens CPAP weaning time, CPAP duration, oxygen duration, BPD and admission time.

Review article: Non-invasive assessment of cardiac output with portable continuous-wave Doppler ultrasound

Cardiac output is considered an important parameter when assessing the cardiovascular status of a critically ill patient. Both non‐invasive (e.g. bioimpedance, echocardiography) and invasive methods (Swan Ganz catheter) have been used to measure cardiac output. The ultrasonic cardiac output monitoring device provides a new method of non‐invasively assessing cardiac output in various clinical settings. The ultrasonic cardiac output monitoring device was introduced clinically in 2001, and appears to be a promising adjunct in the assessment of the cardiovascular state in a variety of patient cohorts. In this short review article, we will introduce this new technique, discuss the required skills and compare it with methods already in use. In particular, a critical comparison with the ‘gold standard’, the invasive measurement of cardiac output with the pulmonary artery catheter, will be given.

Tracheal damage following conventional and high-frequency ventilation at low and high humidity.

ObjectivesTo compare the degree of tracheobronchial damage in newborn lambs ventilated for 6 hrs with relative humidities of 30% or 90% and continuous positive airway pressure breathing, conventional mechanical ventilation of 25 and 60 breaths/min, or high frequency flow-interrupted ventilation at 600 breaths/min. Background and MethodsTracheobronchial damage secondary to mechanical ventilation remains a major iatrogenic lesion of the newborn despite substantial advances in both mechanical design and ventilatory techniques. A histologie scoring system was used to compare the damage noted in the tracheobronchial epithelium of newborn lambs after 6 hrs of conventional mechanical ventilation or high-frequency flow-interrupted ventilation at two relative humidities.Three groups of animals were ventilated for 6 hrs with an Fio2 of 0.21 at 36.0°C and relative humidity of 90%. The first group received continuous positive airway pressure of 4 cm H2O, the second group received slow rate, conventional mechanical ventilation at 25 breaths/ min, and the third group received fast rate, conventional mechanical ventilation at 60 breaths/min. Two other groups of animals were ventilated for 6 hrs with an Fio2 of 0.21 at 36.0°C and relative humidity of 30%. The first group was ventilated with high-frequency flow-interrupted ventilation at 600 breaths/min and the second group with slow rate, conventional mechanical ventilation at 25 breaths/min. Two additional groups served as nonintubated controls; one group was killed immediately after sedation and the other group was killed after 6 hrs of sedation. ResultsThe damage was mild but significantly different from controls when 90% humidity was used and there was no difference in the histology score between continuous positive airway pressure breathing and conventional mechanical ventilation at 25 or 60 breaths/min. Significant inflammation, erosion, necrosis, and blistering occurred with both conventional mechanical ventilation at 25 breaths/min and high-frequency flow-interrupted ventilation at 600 breaths/min when 30% humidity was used. The damage was only found 5 mm below the tip of the endotracheal tube and not at 3.5 cm beyond the endotracheal tube in the trachea nor in the right main bronchus. ConclusionThese data indicate that endo-tracheal intubation and mechanical ventilation, regardless of the method of ventilation, cause damage to the tracheal mucosa, but that poorly humidified inspired gases cause significantly greater damage.

Assessment of portable continuous wave Doppler ultrasound (ultrasonic cardiac output monitor) for cardiac output measurements in neonates.

Background and study purpose:  The ultrasonic cardiac output monitoring (USCOM, USCOM Pty Ltd, Coffs Harbour, NSW, Australia) device provides a new method of non‐invasively assessing cardiac output (CO). It has been successfully used in adults, but there have been few studies in neonates.

Retinopathy of prematurity in infants < 32 weeks’ gestation at birth in New South Wales in 1993 and 1994

Objective: To study the incidence and severity of retinopathy of prematurity (ROP) in infants < 32 weeks’ gestation.

Retinopathy of prematurity in infants <29 weeks’ gestation at birth in New South Wales from 1986–92

To study the effect of increased survival of infants <29 weeks’ gestation on the incidence and severity of retinopathy of prematurity (ROP).

Evaluation of bubble clicking in gastric aspirate in the newborn

ABSTRACT. Bubble clicking, foam stability tests, L/S ratio and two dimensional thin layer chromatography were done in 26 gastric aspirates obtained from 22 babies with mature lungs and 4 babies with with hyaline membrane disease.

CeasIng Cpap At standarD criteriA (CICADA): impact on weight gain, time to full feeds and caffeine use

Introduction In our previous randomised controlled trial (RCT), we have shown in preterm babies (PBs) <30 weeks gestation that CeasIng Cpap At standarD criteriA (CICADA (method 1)) compared with cycling off continuous positive airway pressure (CPAP) gradually (method 2) or cycling off CPAP gradually with low flow air/oxygen during periods off CPAP (method 3) reduces CPAP cessation time in PBs <30 weeks gestation. Method This retrospective study reviewed weight gain, time to reach full feeds and time to cease caffeine in PBs previously enrolled in the RCT. Results Data were collected from 162 of the 177 PBs, and there was no significant difference in the projected weight gain between the three methods. Based on intention to treat, the time taken to reach full feeds for all three methods showed no significant difference. However, post hoc analysis showed the CICADA method compared with cycling off gradually just failed significance (30.3±1.6 vs 31.1±2.4 (weeks corrected gestational age (Wks CGA±SD)), p=0.077). Analysis of time to cease caffeine showed there was a significant difference between the methods with PBs randomised to the CICADA method compared with the cycling off method ceasing caffeine almost a week earlier (33.6±2.4 vs 34.5±2.8 (Wks CGA±SD), p=0.02). Conclusions This retrospective study provides evidence to substantiate the optimum method of ceasing CPAP; the CICADA method, does not adversely affect weight gain, time to reach full feeds and may reduce time to cease caffeine in PBs <30 weeks gestation.

Respiratory outcomes study (RESPOS) for preterm infants at primary school age

Abstract Objective: Pulmonary function abnormalities and hospital re-admissions in survivors of neonatal lung disease remain highly prevalent. The respiratory outcomes study (RESPOS) aimed to investigate the respiratory and associated atopy outcomes in preterm infants <30 weeks gestational age (GA) and/or birth-weight (BWt) <1000 g at primary school age, and to compare these outcomes between infants with and without chronic lung disease (CLD). Methods: In the RESPOS 92 parents of preterm infants admitted to the Neonatal unit in Canberra Hospital between 1/1/2001 and 31/12/2003 were sent a questionnaire regarding their respiratory, atopy management and follow-up. Results: Fifty-three parents responded, including 28 preterm infants who had CLD and 25 who had no CLD. The gestational age was significantly lower in the CLD group compared to the non-CLD group [26.9 (26.3–27.5) CLD and 28.6 (28.3–29.0) non-CLD] [weeks [95% confidence interval (CI)]], as was the birth weight [973 (877.4–1068.8) CLD versus 1221 (1135.0–1307.0) non-CLD] [g (CI)]. CLD infants compared to non-CLD infants were significantly more likely to have been: given surfactant, ventilated and on oxygen at 28 days and 36 weeks. These neonates were also more likely to have: been discharged from the neonatal unit on oxygen, exhibit a history of PDA or sepsis and to have a current paediatrician. However, despite these differences, there was no significant difference in the proportion of asthma or atopic disease between the two groups. Conclusions: The RESPOS could not demonstrate respiratory and/or atopy differences between the CLD and the non-CLD groups at primary school age.