The influence of physiotherapy and suction on respiratory deadspace in ventilated children.
OBJECTIVE
To assess and compare the effects of respiratory physiotherapy and suction on deadspace volumes, carbon dioxide elimination (VCO(2)), end tidal CO(2) (ETCO(2)), and arterial partial pressure of carbon dioxide (PaCO(2)) in ventilated infants and children.


METHODS
Randomised crossover study. Participants received both treatments with a washout interval of more than 90 min.


METHODS
Intensive tertiary care units, Great Ormond Street Hospital, London.


METHODS
Eighty-seven fully ventilated children, requiring physiotherapy, with arterial lines in situ. Paired measurements were obtained in 81 patients, of whom 6 were excluded because of tracheal tube leak greater than 20%.


METHODS
Respiratory physiotherapy and suction.


RESULTS
Data were collected April 1998-March 2000. The "CO(2)SMO Plus" respiratory monitor was used to calculate parameters before and 30 min after both interventions. Physiotherapy lasted longer and required more saline and catheters per treatment ( p<0.005). There were significant increases in physiological deadspace (VD(phys))/kg ( p<0.0001), alveolar deadspace (VD(alv))/kg ( p<0.0001) and VD(phys)/tidal volume (V(T)) ( p<0.05) following physiotherapy that were not observed following suction. There were no significant changes following either treatment with respect to airway deadspace (VD(airway)), VCO(2) or PaCO(2). Comparison of the mean differences following treatments indicated significant differences between physiotherapy and suction in terms of VD(phys)/kg ( p<0.005), VD(alv)/kg ( p<0.005), expired tidal volumes (V(TE)) ( p<0.05), mixed expired CO(2) (PeCO(2)) ( p<0.04) and ETCO(2) ( p<0.03).


CONCLUSIONS
Differences between physiotherapy and suction techniques probably accounted for their statistically distinguishable effects on deadspace. VD(phys) and VD(alv) may be more sensitive indicators of subtle changes in gas exchange and regional ventilation than VCO(2) or PaCO(2). However, interpretation of these outcomes is dependent on concurrent examination of the parameters from which they are derived.
Main
Eleanor
E
Centre for Nursing and Allied Health Professionals Research and Physiotherapy Department, Institute of Child Health, 7th Floor, Old Building, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London WCIN 3JH, UK. maine@gosh.nhs.uk
Stocks
Janet
J
D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008297:Male; D012121:Respiration, Artificial; D012126:Respiratory Dead Space; D015656:Respiratory Mechanics; D012138:Respiratory Therapy; D013396:Suction; D016896:Treatment Outcome