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doi:10.1111/jpc.12724
ORIGINAL ARTICLE
Is it feasible to identify preterm infants with respiratory distress syndrome for early extubation to continuous positive airway pressure post-surfactant treatment during retrieval? Archana Priyadarshi,1 Wei Shern Quek,2 Melissa Luig3 and Kei Lui1,2 1 New Born Care Centre, Royal Hospital for Women, 2Department of Pediatrics, The University of New South Wales and 3NETS: Newborn and Paediatric Emergency Transport Services, Sydney, New South Wales, Australia
Aim: Preterm infants with respiratory distress syndrome (RDS) requiring surfactant treatment are often retrieved mechanically ventilated to the receiving hospital. INSURE (INtubate, SURfactant, Extubate) technique is not routinely performed by Newborn and Pediatric Emergency Transport Services NSW (NETS) during retrieval. This study aims to evaluate the likelihood of using INSURE technique during retrieval. We attempted to study the clinical characteristics of preterm infants with RDS who were favourably extubated (FE) shortly after admission to the receiving hospital. Methods: Retrospective study of preterm infants, gestational age (GA) > 28 weeks with RDS requiring retrieval by NETS. Results: Two hundred twenty-three infants, median GA of 33 weeks (range 29–36), median birthweight 2200 g (1000–4080) were examined. A percentage of 49.7 received CPAP, and 50.3% required MV. Eighteen (16%) infants were FE (28 weeks gestation, birthweight ≥1000 g, ≤48 h age with diagnosis of RDS retrieved from 1st January 2010 to 31st December 2011 by NETS. Data were collected from NETS database, their chart records along with follow-up of these infants at the receiving neonatal intensive care units in NSW. Exclusion criteria included preterm infants 6 h (nonFE) group. A possible correlation between FiO2 on stabilisation by NETS and FiO2 on admission to the receiving hospital was questioned and tested. The study is based on the assumption that any infant successfully extubated to CPAP within 6 h of admission to the receiving hospital without any comorbidity at the time of discharge was a potential candidate for receiving surfactant by INSURE technique at the referral hospital with NETS transfer on CPAP. Data were analysed using Statistical Package for Social Science (SPSS) software, version 21.0 (IBM Corp., Armonk, NY, USA). Variables were expressed in percentages and means ± standard deviation on data with normal distribution, median (range) for skewed data. Qualitative variables were compared with χ2 test and Fisher’s exact test. Quantitative variables were compared using Student’s t-test. Differences were considered significant for P-value < 0.05. All variables with P-value < 0.05 were included in model of logistic regression with calculation of adjusted odds ratios and 95% confidence intervals (CIs). Finally a prediction analysis was done for variables associated with FE group. These variables were tested for predictive value using receiver operating characteristic (ROC) curve for sensitivity and specificity cut-off points.
Results The study assessed data between 1st January 2010 to 31st December 2012. A total of 251 preterm infants were diagnosed with RDS and retrieved by NETS. Twenty-eight infants were excluded from the study for incomplete data on follow-up at the receiving hospital. The median gestation of 223 study infants was 33 weeks (range 29–36) with median birthweight of 2200 g (1000–4080 g). A percentage of 39 were given one or two doses of antenatal steroids, and their median age at time of first call to NETS was 4 h (0–47 h). Data on the respiratory support used by NETS along with mode of transport are summarised in Figure 1 and Table 1. Total of 217 infants were retrieved receiving positive pressure support of which 112 infants were mechanically ventilated post one dose of surfactant treatment, whereas 105 infants were retrieved using CPAP only with no surfactant treatment. Premedications were commonly used (81.3%) prior to intubation in ventilated infants. The ventilated infants had a higher FiO2 on first look by NETS and at the time of stabilisation at the referral hospital. The clinical characteristics of all retrieved infants are summarised in Table 2. None of the retrieved infants had any adverse events during transport. All ventilated infants (n = 112) were categorised into two groups based on their time of extubation on arrival at the receiving hospital. Eighteen (16%) infants were successfully extubated within first 6 h of admission. Ninety-four (84%) were ventilated with mean duration of 39 h (7–192). The clinical characteristics of 18 FE infants were compared against the non-FE group (Table 3). FE infants had a signifi-
Journal of Paediatrics and Child Health 51 (2015) 321–327 © 2014 The Authors Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians)
A Priyadarshi et al.
Fig. 1
Intubate-surfactant-extubate in retrieval
Flow chart showing respiratory support used by NETS and mode of transport.
Table 1 Change in the type of respiratory support at time of 1st call to NETS, upon first-look by NETS, at stabilisation and transport by NETS to destination hospital (n = 223) Type of resp. support used
Resp. support at first referral call to NETS
Resp. support on first-look by NETS
Resp. support at stabilisation and transport by NETS
IPPV, n (%) CPAP, n (%) High flow, n (%) Head box, n (%) Crib oxygen, n (%)
20 (8.9%) 127 (56.7%) 2 (0.9%) 64 (28.6%) 10 (4.9%)
42 (18.8%) 139 (62.1%) 2 (0.9%) 32 (14.3%) 8 (2.6%)
112 (50.2%) 105 (47.0%) – – 6 (2.7%)
CPAP, continuous positive airway pressure; IPPV, intermittent positive pressure ventilation.
FiO2 on first look and stabilisation by NETS, retrieval time, premedications used for intubation and PPHN failed to show any variable as statistically significant. Subsequently on stepwise backward elimination, FiO2 on stabilisation was the only independent discriminative predictor between FE and non-FE groups. To identify suitable sensitivity and specificity cut-off points for clinical practice, ROC curve was plotted for the variable FiO2 on stabilisation by NETS (Fig. 3). The area under the curve (AUC) in predicting FE was 0.646 (95% CI: 0.513–0.779; P = 0.05). Within the cut-off points of FiO2 0.25–0.30, the sensitivity ranged from 0.68 to 0.47 and the specificity ranged from 0.61 to 0.44. Conversely, none of the ventilated infants with FiO2 on stabilisation of >0.45 were favourably extubated. Similarly none of the ventilated infants with FiO2 requirement of 0.40 at the receiving hospital were favourably extubated early.
Discussion cantly lower FiO2 on first look and stabilisation by NETS prior to transport but had otherwise similar ventilator requirements. After admission to the receiving hospital, none of the FE infants had any comorbidities at time of discharge. Among those extubated later (n = 94), nine (8%) had pulmonary hypertension of the newborn (PPHN), five (4.5%) needed treatment for patent ductus arteriosus, nine had intra-ventricular haemorrhage (any grade IVH), seven infants had late onset sepsis, three had necrotising enterocolitis and seven had chronic lung disease at 36 weeks post-conceptional age. In all the ventilated infants, a clear linear relationship was noted on FiO2 after stabilisation by NETS post surfactant treatment at referral hospital and FiO2 on admission to the receiving hospital (slope = 0.85, r = 0.86, P < 0.001; see Fig. 2). A multiple logistic regression analysis for possible predictors of early extubation was performed on variables such as birthweight,
INSURE method has been shown in randomised control trials to reduce the need of mechanical ventilation and subsequent bronchopulmonary dysplasia in preterm infants with RDS that require surfactant treatment.15 All trials on INSURE have been done in controlled neonatal intensive care setting with no data on its use in retrieval setting. Intubation, administration of surfactant with subsequent immediate extubation to CPAP prior to transport, has not been a management strategy at NETS. Thus, we explored the feasibility of implementing INSURE in a cohort of moderately preterm infants to identify potential suitable infants who may be offered the benefits of INSURE. In this study, we selected a group of moderately preterm infants >28 weeks with birthweight ≥1000 g, as previous studies done by Dani et al.1 showed birthweight
doi:10.1111/jpc.12724
ORIGINAL ARTICLE
Is it feasible to identify preterm infants with respiratory distress syndrome for early extubation to continuous positive airway pressure post-surfactant treatment during retrieval? Archana Priyadarshi,1 Wei Shern Quek,2 Melissa Luig3 and Kei Lui1,2 1 New Born Care Centre, Royal Hospital for Women, 2Department of Pediatrics, The University of New South Wales and 3NETS: Newborn and Paediatric Emergency Transport Services, Sydney, New South Wales, Australia
Aim: Preterm infants with respiratory distress syndrome (RDS) requiring surfactant treatment are often retrieved mechanically ventilated to the receiving hospital. INSURE (INtubate, SURfactant, Extubate) technique is not routinely performed by Newborn and Pediatric Emergency Transport Services NSW (NETS) during retrieval. This study aims to evaluate the likelihood of using INSURE technique during retrieval. We attempted to study the clinical characteristics of preterm infants with RDS who were favourably extubated (FE) shortly after admission to the receiving hospital. Methods: Retrospective study of preterm infants, gestational age (GA) > 28 weeks with RDS requiring retrieval by NETS. Results: Two hundred twenty-three infants, median GA of 33 weeks (range 29–36), median birthweight 2200 g (1000–4080) were examined. A percentage of 49.7 received CPAP, and 50.3% required MV. Eighteen (16%) infants were FE (28 weeks gestation, birthweight ≥1000 g, ≤48 h age with diagnosis of RDS retrieved from 1st January 2010 to 31st December 2011 by NETS. Data were collected from NETS database, their chart records along with follow-up of these infants at the receiving neonatal intensive care units in NSW. Exclusion criteria included preterm infants 6 h (nonFE) group. A possible correlation between FiO2 on stabilisation by NETS and FiO2 on admission to the receiving hospital was questioned and tested. The study is based on the assumption that any infant successfully extubated to CPAP within 6 h of admission to the receiving hospital without any comorbidity at the time of discharge was a potential candidate for receiving surfactant by INSURE technique at the referral hospital with NETS transfer on CPAP. Data were analysed using Statistical Package for Social Science (SPSS) software, version 21.0 (IBM Corp., Armonk, NY, USA). Variables were expressed in percentages and means ± standard deviation on data with normal distribution, median (range) for skewed data. Qualitative variables were compared with χ2 test and Fisher’s exact test. Quantitative variables were compared using Student’s t-test. Differences were considered significant for P-value < 0.05. All variables with P-value < 0.05 were included in model of logistic regression with calculation of adjusted odds ratios and 95% confidence intervals (CIs). Finally a prediction analysis was done for variables associated with FE group. These variables were tested for predictive value using receiver operating characteristic (ROC) curve for sensitivity and specificity cut-off points.
Results The study assessed data between 1st January 2010 to 31st December 2012. A total of 251 preterm infants were diagnosed with RDS and retrieved by NETS. Twenty-eight infants were excluded from the study for incomplete data on follow-up at the receiving hospital. The median gestation of 223 study infants was 33 weeks (range 29–36) with median birthweight of 2200 g (1000–4080 g). A percentage of 39 were given one or two doses of antenatal steroids, and their median age at time of first call to NETS was 4 h (0–47 h). Data on the respiratory support used by NETS along with mode of transport are summarised in Figure 1 and Table 1. Total of 217 infants were retrieved receiving positive pressure support of which 112 infants were mechanically ventilated post one dose of surfactant treatment, whereas 105 infants were retrieved using CPAP only with no surfactant treatment. Premedications were commonly used (81.3%) prior to intubation in ventilated infants. The ventilated infants had a higher FiO2 on first look by NETS and at the time of stabilisation at the referral hospital. The clinical characteristics of all retrieved infants are summarised in Table 2. None of the retrieved infants had any adverse events during transport. All ventilated infants (n = 112) were categorised into two groups based on their time of extubation on arrival at the receiving hospital. Eighteen (16%) infants were successfully extubated within first 6 h of admission. Ninety-four (84%) were ventilated with mean duration of 39 h (7–192). The clinical characteristics of 18 FE infants were compared against the non-FE group (Table 3). FE infants had a signifi-
Journal of Paediatrics and Child Health 51 (2015) 321–327 © 2014 The Authors Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians)
A Priyadarshi et al.
Fig. 1
Intubate-surfactant-extubate in retrieval
Flow chart showing respiratory support used by NETS and mode of transport.
Table 1 Change in the type of respiratory support at time of 1st call to NETS, upon first-look by NETS, at stabilisation and transport by NETS to destination hospital (n = 223) Type of resp. support used
Resp. support at first referral call to NETS
Resp. support on first-look by NETS
Resp. support at stabilisation and transport by NETS
IPPV, n (%) CPAP, n (%) High flow, n (%) Head box, n (%) Crib oxygen, n (%)
20 (8.9%) 127 (56.7%) 2 (0.9%) 64 (28.6%) 10 (4.9%)
42 (18.8%) 139 (62.1%) 2 (0.9%) 32 (14.3%) 8 (2.6%)
112 (50.2%) 105 (47.0%) – – 6 (2.7%)
CPAP, continuous positive airway pressure; IPPV, intermittent positive pressure ventilation.
FiO2 on first look and stabilisation by NETS, retrieval time, premedications used for intubation and PPHN failed to show any variable as statistically significant. Subsequently on stepwise backward elimination, FiO2 on stabilisation was the only independent discriminative predictor between FE and non-FE groups. To identify suitable sensitivity and specificity cut-off points for clinical practice, ROC curve was plotted for the variable FiO2 on stabilisation by NETS (Fig. 3). The area under the curve (AUC) in predicting FE was 0.646 (95% CI: 0.513–0.779; P = 0.05). Within the cut-off points of FiO2 0.25–0.30, the sensitivity ranged from 0.68 to 0.47 and the specificity ranged from 0.61 to 0.44. Conversely, none of the ventilated infants with FiO2 on stabilisation of >0.45 were favourably extubated. Similarly none of the ventilated infants with FiO2 requirement of 0.40 at the receiving hospital were favourably extubated early.
Discussion cantly lower FiO2 on first look and stabilisation by NETS prior to transport but had otherwise similar ventilator requirements. After admission to the receiving hospital, none of the FE infants had any comorbidities at time of discharge. Among those extubated later (n = 94), nine (8%) had pulmonary hypertension of the newborn (PPHN), five (4.5%) needed treatment for patent ductus arteriosus, nine had intra-ventricular haemorrhage (any grade IVH), seven infants had late onset sepsis, three had necrotising enterocolitis and seven had chronic lung disease at 36 weeks post-conceptional age. In all the ventilated infants, a clear linear relationship was noted on FiO2 after stabilisation by NETS post surfactant treatment at referral hospital and FiO2 on admission to the receiving hospital (slope = 0.85, r = 0.86, P < 0.001; see Fig. 2). A multiple logistic regression analysis for possible predictors of early extubation was performed on variables such as birthweight,
INSURE method has been shown in randomised control trials to reduce the need of mechanical ventilation and subsequent bronchopulmonary dysplasia in preterm infants with RDS that require surfactant treatment.15 All trials on INSURE have been done in controlled neonatal intensive care setting with no data on its use in retrieval setting. Intubation, administration of surfactant with subsequent immediate extubation to CPAP prior to transport, has not been a management strategy at NETS. Thus, we explored the feasibility of implementing INSURE in a cohort of moderately preterm infants to identify potential suitable infants who may be offered the benefits of INSURE. In this study, we selected a group of moderately preterm infants >28 weeks with birthweight ≥1000 g, as previous studies done by Dani et al.1 showed birthweight
