L. Rodriguez et al., A new simple method to perform pressure-volume curves obtained under quasi-static conditions during mechanical ventilation, INTEN CAR M, 25(2), 1999, pp. 173-179
Objective: To describe a fast, simple method to acquire pressure-volume cur
ves of the respiratory system and to compare this with a classic method in
terms of reliability of the data and speed.
Design: Acquisition of pressure-volume curves by low flow inflation techniq
ue (P-Vlf) versus the occlusion technique (P-Vst) using the standard equipm
ent of a Cesar ventilator.
Setting: General ICU - Aix en Provence Hospital.
Patients: Ten sedated, curarized pa tients undergoing mechanical ventilatio
n.
Interventions: P-Vlf curves were acquired by setting the ventilator paramet
ers at f = 5 c./min, duty time Ti/Ttot = 80 %, V-T = 1100 ml, pause time =
0. The pressure and volume data were collected directly on the ventilator s
creen. P-Vst curves were acquired using an airway occlusion technique. The
pressures obtained for the same inflation volumes and times necessary for p
erformance of the two techniques were compared.
Results: The time needed to acquire a P-Vlf curve was 3 min versus 38 min f
or P-Vst curve. Concordance analysis between the two methods showed a 95 %
confidence interval of (-0.5 cm H2O, + 1.8 cm H2O) for pressure.
Conclusions: P-Vlf curves are close to P-Vst curves, are much less time-con
suming, easy to acquire with Cesar ventilator equipment, and may be used in
clinical routine to assess the elastic properties of the respiratory syste
m.