Non invasive mechanical ventilation (NINMV) in cardiac surgery

Full text

Objective

To evaluate the efficacy of NINMV in cardiac surgical patients. In order to verify if, beside already established advantages in critical care patients [1] (less intubation related complications, minor discomfort for patients and less need for sedation), NINMV can be useful in managing the weaning process in the postoperative cardiac surgical course.

Design

Retrospective survey. We used NINMV with two indications: (1) patients with unexpected postoperative respiratory failure requiring reintubation; (2) patients extubated early and with incomplete postoperative recovery of cardiorespiratory stability.

Setting

Five bed intensive care unit at a cardiothoracic surgery centre.

Patients

Twenty NINMV patients representing 4.1% of the 484 patients operated on from October 1998 to September 1999 in our centre. Urgent surgery occurred in 12% of cases, emergency surgery in 4.75% of cases. Overall in-hospital mortality was 14/484 (2.2%).

Interventions

We use a nasal or facial mask (Respironics Inc., Murrysville, Pennsylvania, USA) connected to a Servo Ventilator 300 (Siemens-Elema, Sweden). Patients were ventilated by Pressure Support (10–15 cmH₂0) with PEEP (5–8 cmH₂O). Intermittent periods of NINMV were alternated with periods of spontaneous breathing accordingly to patients needs. Sedation was obtained by Remifentanyl infusion in the range 0.03–0.07 γ kg^-1min^-1.

Measurements and main results

Twenty patients. were treated by NINMV (two with indication 1 and 18 patients. with indication 2). The two patients with indication 1 were successfully weaned and discharged. None of the other 484 patients in this series needed reintubation.

Table 1 characterises patients with indication 2 and summarises results.

Only 3 patients had to be reintubated (n°3 for unexpected haematological complication, n°8 for psychotic disturbances, n°18 failed full haemodynamic recovery).

Table 1

Conclusions

NINMV patients with indication 2 were weaned from respiratory support earlier than usual during a complicated postoperative course. The good results of our series suggest that NINMV indication 2 can be viewed as a weaning model. The most severe forms of circulatory impairment and the non-collaborative patient seem to be, accordingly to literature, exclusion criteria. A wider study would better precise inclusion and exclusion criteria in cardiac surgical patients.