1998, Number 3
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Med Crit 1998; 12 (3)
Work of breathing according flow by triggering level in patients on pressure support ventilation
Osorio BJA, Franco GJ, Martínez SJ, Elizalde GJJ
Language: Spanish
References: 27
Page: 95-101
PDF size: 122.17 Kb.
ABSTRACT
Objective. To asses the effect of the flow-by (Fb) on the imposed work of breathing (WOBp) on pressure support ventilation (PSV) as a weaning tool.
Design. A case series study.
Setting. An ICU of a teaching hospital in Mexico City.
Patients. Twelve patients (eight males and four women, mean age 62.9
14.4 years) with prolonged AMV or difficulty weaning were included.
Interventions. WOBp was determined using a Bicore pulmonary monitor. Fb protocol included a basal flow (Vf) = 12 L/min and 6, 3 and 1 L/min of triggering flow (Vtr), where WOBp was determined at two different levels of PSV: high PSV (level at the beginning of the spontaneous mode) and low PSV (level previous to extubation).
Results. In high PSV (15.3 33.7 cmH2O) the WOBp with Vtr of 6, 3 and 1 was 0.19 0.3 J/L), 0.15 0.28 J/L, and 0.12 0.27 J/L, respectively. In low PSV (5.8 1.1 cmH2O), WOBp with Vtr of 6, 3 and 1 was 1.26 0.5, 1.05 0.42 and 0.79 0.4 J/L, respectively). An statistically difference of WOBp (p ‹ 0.05) was found at low PSV level between Vtr of 6 (1.26 0.5 J/L) and Vtr o 1 (0.79 0.4 J/L).
Conclusions. WOBp decrease with low Vtr. We propose the use of smallest Vtr (1 L/min) in difficult weaning patients.
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