Objective: To assess and compare the effects of physiotherapy and suction on expired tidal volume (V(TE)), respiratory compliance (C(rs)), resistance (R(rs)) and arterial blood gases.
Design: Randomised cross-over study comparing outcomes after both treatments on the same day.
Setting: Intensive tertiary care units, Great Ormond Street Hospital, London.
Patients: One hundred children on full ventilatory support requiring physiotherapy. Paired measurements were obtained in 90 participants, and 7 others were excluded because of tracheal tube leak.
Interventions: Respiratory physiotherapy and suction.
Measurements and results: Physiotherapy lasted longer and required more saline and catheters per treatment. There were no significant group changes in V(TE) or C(rs) after either treatment, but a tendency for R(rs )to fall following physiotherapy which reached significance in patients on volume-preset ventilation. There were also small but statistically significant reductions in HCO(3)(-), base excess and SaO(2) after physiotherapy. V(TE) and C(rs) increased and R(rs) decreased in excess of their 95% limits of agreement for normal variability in approximately twice as many subjects following physiotherapy than suction, these differences being significant for V(TE) and approaching significance for C(rs) and R(rs).
Conclusions: Physiotherapy appeared to have an advantage in reducing R(rs )in some patients, but also produced changes in derived blood gas parameters. Within individuals, physiotherapy treatments were also more likely to produce improvements in V(TE), C(rs) and R(rs) than suction. Further research should identify sensitive patient selection criteria and assess longer-term effects of such treatments.