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Intensive Care Med. 2007 Jul;33(7):1139-1147. doi: 10.1007/s00134-007-0630-2. Epub 2007 Apr 26.

Sleep during proportional-assist ventilation with load-adjustable gain factors in critically ill patients.

Author information

1
Department of Intensive Care Medicine, University Hospital of Heraklion, University of Crete, Heraklion, 711 10, Crete, Greece.
2
Department of Intensive Care Medicine, University Hospital of Heraklion, University of Crete, Heraklion, 711 10, Crete, Greece. georgop@med.uoc.gr.

Abstract

BACKGROUND:

Proportional-assist ventilation with load-adjustable gain factors (PAV+) automatically adjusts the flow and volume assist to represent constant fractions of resistance and elastance of the respiratory system, respectively. Resistance and elastance are calculated at random intervals of 4-10 breaths, by applying a 300 ms pause maneuver at the end of selected inspirations.

OBJECTIVES:

To determine whether the large number of end-inspiratory occlusions during PAV+ operation influences sleep quality in critically ill patients who exhibited good patient-ventilator synchrony during pressure support (PS, baseline).

METHODS:

One and two nights' polysomnography was performed in sedated (protocol A, n=11) and non-sedated (protocol B, n=9) patients, respectively, while respiratory variables were continuously recorded. In each protocol the patients were ventilated with PAV+ and PS at two levels of assist (baseline and high).

RESULTS:

In both protocols sleep quality did not differ between the modes of support or the assist levels. In sedated patients sleep efficiency was slightly but significantly higher with PAV+ than with high PS, while it did not differ between modes in non-sedated patients. The two modes of support had comparable effects on respiratory variables. Independent of the mode of support and particularly at high assist, a significant proportion of patients developed periodic breathing during sleep (27% in protocol A and 44% in protocol B).

CONCLUSION:

In patients exhibiting good patient-ventilator synchrony during PS, the large number of short-term end-inspiratory occlusions with PAV+ operation did not adversely influence sleep quality. With both modes high assist may cause unstable breathing during sleep.

PMID:
17458541
DOI:
10.1007/s00134-007-0630-2
[Indexed for MEDLINE]

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