A home respiratory support programme for children by parents and layperson carers.

AIM: To describe a respiratory support programme for children at home by parents and layperson carers. METHODS: Analysis of records of children with long-term mechanical respiratory support at home. RESULTS: From 1979 to 2008 the programme managed 168 children (median age 7 years, range 3 weeks-19 years) with obstructive sleep apnoea (55, 32%), neuromuscular conditions (42, 25%), tracheo-bronchomalacia (23, 14%), kyphoscoliosis-cerebral palsy (20, 12%), acquired central hypoventilation (8, 5%), congenital central hypoventilation (7, 4%), chronic lung disease or pulmonary hypoplasia (8, 5%), traumatic quadriplegia (3, 2%) and tumour-related quadriplegia (2, 1%). One hundred and sixty-one (96%) were discharged: 73 (46%) remain in the programme; 27 (16%) transferred to adult services, 25 (15%) recovered and 36 (23%) died. Principal modes of therapy were mask continuous positive airway pressure (CPAP) 35%, mask bilevel positive airway pressure 30%, tracheostomy CPAP 20%, tracheostomy mechanical ventilation 8%, phrenic nerve pacing 3%, negative pressure chamber ventilation 2% and nasal tube CPAP 2%. Two unexpected deaths occurred at home: one from accidental tracheostomy decannulation and another unrelated to respiratory support. Average time in the programme was 3.3 years. Parents of 69 children were provided with trained carers. Successful discharge resulted from early recognition of potential to discharge, parental training, recruitment and training of carers, purchase of equipment and secure funding. Seven children were not discharged, two of whom died in the hospital and five are subject to discharge planning. CONCLUSION: Respiratory support of children at home by trained parents and layperson carers is safe and efficient. All modes of respiratory support may be used.

Estimating inspired oxygen concentration delivered by nasal prongs in children with bronchiolitis.

AIMS: The inspired oxygen concentration (FiO(2)) is an important criterion for assessing the severity of bronchiolitis. Oxygen delivery by nasal prongs is a measure of oxygen flow, but not FiO(2). We aimed to determine whether FiO(2) of oxygen delivered by nasal prongs could be predicted from nasal flow by relating arterial oxygen concentrations achieved with prongs to those achieved via head box in children with bronchiolitis. METHODS: This is a pilot study conducted at a tertiary referral paediatric hospital. We studied hospitalised children less than 24 months old requiring supplemental oxygen because of bronchiolitis, an acute viral lower respiratory tract infection. Children admitted to the intensive care unit, and those with congenital cardiac disease or recent bronchodilator use were excluded. Subjects were studied in nasal prong, then head box oxygen. Arterial oxygen concentration was measured by a transcutaneous probe (tcPO(2)). Oxygen flows by nasal prongs and FiO(2) by head box were adjusted to achieve similar tcPO(2) readings. FiO(2) values were plotted against oxygen flow rates based on matching tcPO(2). RESULTS: We recorded tcPO(2) across a satisfactory range of values in eight children. TcPO(2) increased with increasing FiO(2) and nasal oxygen flow, but at variable rates between subjects. FiO(2) increased with increasing nasal oxygen flow, but this relationship was highly variable. CONCLUSIONS: In this study, it was not possible to estimate FiO(2) reliably from nasal oxygen flow rates in children with bronchiolitis. Nasal prong oxygen flow rates should be used with caution when assessing the severity of bronchiolitis in children.

Oxygen delivery using self-inflating resuscitation bags.

OBJECTIVE: Oxygen-filled self-inflating resuscitators are used by some as a source of oxygen for spontaneously breathing patients. In this application, the bag is not compressed and oxygen is assumed to flow freely from the patient outlet through a mask positioned loosely over the patient's face. We tested 11 resuscitators to determine the delivery of oxygen from the patient outlet using different inlet flows. DESIGN: Bench test. SETTING: A pediatric intensive care unit. INTERVENTIONS: Patient outlet flow was measured at inlet flows of 5, 10, and 15 L/min at two different orientations of the reservoir valve assembly (upright and inverted). MEASUREMENTS AND MAIN RESULTS: Patient outlet flow varied between resuscitators but was always less than the inlet flow and, in some cases, was as little as approximately 20% of the inlet flow. As the inlet flow rate was increased, the percentage of outlet flow that a patient received decreased, particularly in the upright position. At inlet flows of 5, 10, and 15 L/min, patient outlet flow ranged from 1.1 to 4.6 L/min, 1.6 to 5.1 L/min, and 2.0 to 6.5 L/min, respectively. CONCLUSIONS: Self-inflating resuscitators deliver a significantly lower flow of oxygen than the provided inlet flow and should not be relied on to deliver a precise amount of flow of oxygen to spontaneously breathing patients.

The effect of inlet gas temperatures on heated humidifier performance.

The aim of the current study was to determine the temperature range of gas at the point at which it passes into a heated humidifier within an intensive care unit and to experimentally examine the effect of different inlet gas temperatures on the performance of a heated humidifier. Various gas and ambient temperatures were measured in an intensive care unit and within ventilator circuits. Ventilator oxygen and air inlet temperatures, ventilator gas outlet temperatures, and humidifier gas inlet temperatures were measured in conjunction with the use of a number of ventilators. Ambient temperatures within the ward ranged from 22.8 degrees C to 28.9 degrees C, while typical ward humidifier gas inlet temperatures ranged from 24.3 degrees C to 28.8 degrees C. Humidity output from a heated humidifier was then determined in an experimental setup at controlled levels of inlet gas temperature using a constant gas flow. A decrease in humidity production, from approximately 36 mg/L at a humidifier inlet gas temperature of 18 degrees C, to 26 mg/L at a humidifier inlet gas temperature of 32 degrees C, was observed with increasing gas inlet temperature. We conclude that humidity output from a heated humidifier varies with inlet gas temperature, decreasing as inlet gas temperature increases. Inlet gas temperatures above 26 degrees C may result in inadequate humidification.