Περίληψη:
Purpose: To assess the short-term effects of pressure support
ventilation in adult respiratory distress syndrome (ARDS), we studied 17
patients with moderate to severe ARDS using mandatory rate ventilation
(MRV), a servocontrolled mode of PSV having respiratory rate as the
targeted parameter.
Materials and Methods: Based on the duration of ARDS, the patients were
divided into two groups: Group 1, early ARDS (duration up to 1 week), 10
patients; Group 2, intermediate ARDS (duration between 1 and 2 weeks).
The patients were initially ventilated with assisted mechanical
ventilation then with MRV, and finally with controlled mechanical
ventilation. After a 20-minute period allowed for stabilization in each
mode, ventilatory variables, gas exchange, hemodynamics, and patient’s
inspiratory effort were evaluated.
Results: During MRV blood gases, airway pressures and hemodynamic
variables remained within acceptable limits in all patients. Compared
with assisted mechanical ventilation, during MRV, patients of group 1
decreased their VT and (V) over dot (from 0.64 +/- 0.04 to 0.42 +/- 0.03
L/sec) and increased their TI/TT (from 0.39 +/- 0.03 to 0.52 +/- 0.03).
f did not change. PAO(2) - PaO2 and (Q) over dot/(Q) over dot T
decreased (from 306 +/- 16 to 269 +/- 15 mm Hg, and from 20.2 +/- 1.4 to
17.5 +/- 1.1, respectively), while PaCO2 increased (from 44 +/- 3 to 50
+/- 3 mm Hg). On the contrary, patients of group 2 increased their VT
(from 0.69 +/- 0.02 to 0.92 +/- 0.09 L), decreased their f (from 22.3
+/- 0.5 to 19.3 +/- 0.3 b/min), although they did not change their (V)
over dot and TI/TT. PAO(2) - PaO2 and (Q) over dot S/(Q) over dot T
remained stable. PaCO2 diminished (from 39 +/- 3 to 34 +/- 3 mm Hg).
Pressure support level was higher in group 2 than in group 1 (29.4 +/-
3.0 v 19.8 +/- 2.9 cm H2O).
Conclusions: We conclude that (1) PSV delivered by MRV may adequately
ventilate patients with moderate to severe ARDS, preserving gas exchange
and hemodynamics, at least for the short period tested; (2) early and
intermediate ARDS respond in a different manner to MRV in terms of
breathing pattern, gas exchange, and level of pressure assistance; and
(3) patients with early ARDS are those who have an improvement in
intrapulmonary oxygenation probably due, at least in part, to alveolar
recruitment augmented by active diaphragmatic contraction.
Συγγραφείς:
Zakynthinos, SG
Vassilakopoulos, T
Daniil, Z
Zakynthinos, E
and Koutsoukos, E
Katsouyianni, K
Roussos, C
