COMPARING CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) AND SYNCHRONOUS INTERMITTENT POSITIVE PRESSURE VENTILATION (SIPPV) VIA NASAL CANNULAE AFTER EXTUBATION IN VLBW NEWBORNS (≤1500g)

Abstract 154

In order to evaluate the short term effects of two ventilation techniques via nasal cannulae applied after extubation, 10 newborns (mean BW 1146 g, mean GA 27.7 weeks), extubated by age 14 days (mean age at extubation 6 days) were submitted to two consecutive 45' periods of ventilation with nasal CPAP(3 cm H₂O) and with nasal SIPPV (PEEP 3 cmH₂O, PIP 8-18 cmH₂O Ti 0.3-0.4 secs) within 24 hrs from extubation. Respiratory rate (RR), tidal volume (Vt), minute volume (Ve), esophageal pressure variations (▵Pes) and transcutaneous CO₂ pressure (PtcCO₂) were measured. In 5 patients ventilation was started with nCPAP, followed by nSIPPV; in the other 5 the sequence was inverted, each patient being his/her own control. Vt was measured by jacket plethismography⁽¹⁾ and ▵Pes by means of an air-filled balloon catheter. The Respiratory Effort Index (REI) was calculated as an estimate of muscular work, given by▵Pes/Vt for each breath. An average of 1146 breaths were analysed for each baby: synchronisation between spontaneous and mechanical breaths was observed in 84.6±4.9%, 7.5±2.9% breaths were asynchronous and 7.9±3.8% were not triggered. (*p<0.04; matched samples two-tailed t-test; values refer to mean ± SD)Table During nSIPPV synchronous mechanical breaths determine an increase in Vt, allowing the patient to alter his/her breathing pattern by reducing spontaneous RR. nSIPPV also allows a reduction of the patient's respiratory effort and improves alveolar ventilation.

Table 1