Safety and feasibility of exhaled breath condensate collection in ventilated infants and children

¹ Portex Anaesthesia, Intensive Therapy and Respiratory Medicine Unit, Institute of Child Health & Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
² Dept of Paediatric Surgery, Institute of Child Health & Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK

^* To whom correspondence should be addressed. E-mail: ajaffe{at}doctors.org.uk.

	Abstract

To develop a technique for the collection of exhaled breath condensate (EBC) in ventilated children and assess its safety and feasibility.

Collection of EBC is used to investigate markers of oxidative stress in the lower airway. No studies have assessed its safety in ventilated children.

An in vitro model was developed connecting a ventilator to an artificial lung. 14 clinical and ventilatory parameters were measured during EBC collection in ventilated children. 8-isoprostane was measured following collection with and without humidification of the inhaled gas.

Collected water vapour was linearly related to time (r²=0.99, p<0.0001) and to minute ventilation (r²=0.98, p<0.0001) in the in vitro model.

68 EBC were collected in ventilated children. In the non-humidified group the positive end-expiratory pressure increased by (mean (range)) 4.1% (2.8-5.5) (p<0.0001) and the peak inspiratory flow decreased by 6.1% (11.0-1.3) (p=0.02)) during collection.

Detectable levels of 8-isoprostane were only found in 10 out of 18 non-humidified EBC (median (range) 4.7 pg·mL^-1 (0-5.8)) p<0.0001.

Collection of EBC in ventilated infants and children is feasible and safe. Discontinuation of humidification is likely to be important in standardising the measurement of inflammatory parameters in EBC collection in ventilated children.