Setting and patients
Stavanger University Hospital is both a local and secondary referral hospital and the only hospital for children in South Rogaland, Norway. The annual number of births is approximately 5000 (2011). During the study period, the paediatric ward for children with infectious diseases had 11 beds in single-bed rooms. The ward was staffed with eight nurses during daytime, six during weekends and evenings and four during nights. Three physicians attended the ward during daytime, and two were available during weekends, evenings and nights.
All nurses and physicians in the ward involved with CPAP therapy were trained in practical and technical details before being allowed to participate. An annual training program before each bronchiolitis season was established. Detailed written practical and technical procedures were available for both the physicians and nurses.
The hospital further had a seven-bed ICU for patients of all ages after the neonatal period, which also admitted infants with bronchiolitis in need of intensive care. Referral from the paediatric ward to the ICU could be organised within a few minutes if necessary.
Bronchiolitis was defined as an acute respiratory infection in a child < 12 months of age with typical symptoms of wheezing (prolonged expiration) [1–3]. Infants with bronchiolitis needing hospitalisation were referred to the paediatric ward for infectious diseases. Nasopharyngeal mucus was examined for RSV by direct immunofluorescence in all patients (bioMe’rieux, Marcyl’E’toile, France).
The standard treatment for bronchiolitis in the department is oxygen when needed (to keep the oxygen saturation ≥ 92-94%), fluid and nutritional support (by nasogastric tube or intravenously). During the study period, we regularly treated the infants with racemic adrenaline if the child had bronchopulmonary obstruction or severe cough; 2–4 mg in 2 ml isotonic saline every 2–4 hours as needed , or with only isotonic saline when needed.
Traditionally, when an infant with bronchiolitis demonstrate signs of respiratory failure we have referred the infant to the ICU for treatment with CPAP or mechanical ventilation. From 2008 we have aimed to initially treat infants in need of CPAP in the general paediatric ward without initial referral to the ICU. The study period included four years from May 1st 2008 to April 30th 2012. Only children living in the area for Stavanger University Hospital were included, making the study population based.
CPAP – indications and setup
Children treated with CPAP were given oxygen, fluid support and nebulised racemic adrenaline in advance. The decision to start treatment with CPAP was taken by the physician responsible, but according to in-house guidelines (see list of criteria below).
List of criteria for starting treatment with continuous positive airway pressure (CPAP) or referral to intensive care unit (ICU) in infants with bronchiolitis at Stavanger University Hospital
CPAP is considered for a child with bronchiolitis with
Recurrent episodes of apnoea
Severe respiratory distress; retractions, severe wheezing
Increasing oxygen supply in spite of other treatment
Increasing capillary CO2 (> 6.5-7.0 kPa)
Young age (<2-3 months)
Referral to the ICU is considered when an infant with bronchiolitis in spite of treatment with CPAP at the paediatric ward have
Severe respiratory distress (severe retractions, tachypnoe > 70/min)
High or increasing capillary CO2 (> 6.5-7.0 kPa)
Poor general condition or discomfort
In the paediatric ward we used the CPAP GoodKnight 420E® (Puritan Bennett, Coviden, Mansfield, MS, USA) with two different nasal masks with leaks; ProfileLite Small Child (Philips Respironics, Tangmere, UK) or Infant Bubble Mask (Sullivan Infant Bubble Mask, Resmed, San Diego, CA, USA) which were individually adapted.
The CPAP pressure was set at 5 cm H2O in all cases. Extra oxygen was given as 100% oxygen into the circuit as needed to keep the SpO2 within excepted limits. The nebuliser Aeroneb ProX (Aerogen, Galway, Ireland) was connected to the circuit, allowing inhalations without changing the gas flow to the patient, otherwise the gas was not humidified. Careful nasal suctioning was performed in infants with copious secretion.
For infants treated with CPAP in the ward, SpO2 was continuously monitored by pulse oximetry. A nurse was permanently in the room during the initial phase, during weaning by frequent observations. One of the parents was always with the child in the room. A physician could attend immediately if necessary.
Referral to the ICU was considered if the child was not successfully treated at the paediatric ward; according to criteria given above. Infants referred to the ICU were treated with nasal CPAP using the Dräger Evita XL ventilator (Dräger Medical, Lübeck, Germany) with nasal prongs (Fischer & Paykel Healthcare, Irvine, CA). Initial CPAP pressure was set to 5 cm H2O.
We aimed at measuring a capillary PCO2 (cPCO2) before starting treatment with CPAP, 4–6 hours after CPAP had been initiated, and approximately 12, 24 and 48 hours after the start of treatment if the infant was still on CPAP. Samples for capillary PCO2 was taken and analyzed by laboratorial staff. Data were prospectively registered by nurses on a special record for the project, missing data were retrospectively collected from hospital records. Arterial blood gases were not measured and respiratory distress not systematically registered.
We considered the procedure described as the best treatment for bronchiolitis available based on the literature, and no control group was included [1–3, 7]. The procedure was therefore not considered as a research protocol; the regional ethical committee was consulted and waived the need for approval.
Comparisons between groups were analysed by non-parametric tests for variance; the Kruskal-Wallis test for independent samples and Friedman test for related samples. A p-value < 0.05 was regarded as statistically significant, and all analyses were two-tailed. Data were analysed using the SPSS version 18.0 statistical package (SPSS, Chicago, IL, USA).