[Effect of fluid resuscitation on extravascular lung water in early stage of septic shock]

Abstract

Objective: To determine the effect of fluid resuscitation on extravascular lung water (EVLW) in early stage of septic shock.

Methods: Twenty septic shock patients with hypovolemia [intrathoracic blood volume index (ITBVI)<750 ml/m(2)] were randomly divided into two groups: EVLW index (EVLWI)< or =7 ml/kg group (n=8) and EVLWI >7 ml/kg group (n=12) according to the EVLWI value determined on admission day. Fluid resuscitation was given at 250 ml in bolus every 15 minutes until the end point of ITBVI>850 ml/m(2) was reached. Repeated haemodynamic measurements were done at baseline (Tb), at the end point (T0) then at 1 hour (T1), 2 hours (T2) and 4 hours (T4) after the end point of resuscitation was reached. EVLWI, pulmonary vascular permeability index (PVPI), ITBVI, global end-diastolic volume index (GEDVI), cardiac index (CI), stroke index (SI), central venous pressure (CVP) and oxygenation index (PaO(2)/FiO(2)) were determined at each time point, and the outcomes of these patients after 28 days were recorded.

Results: (1)ITBVI, GEDVI, CI, SI, CVP were increased significantly at T0 and remained elevated at T1 and T2 in two groups (P<0.05 or P<0.01), but declined at T4 with no significant difference compared with those at Tb (all P>0.05). There were also no significant differences at the same period of time between the two groups (all P>0.05). (2)No changes in PaO(2)/FiO(2) and EVLWI were found over time in two groups compared with those at Tb (all P>0.05), but the PaO(2)/FiO(2) in EVLWI>7 ml/kg group were all lower than that of EVLWI< or =7 ml/kg group at any time point (all P<0.05). (3)EVLWI was not significantly correlated with ITBVI, GEDVI, CI, SI, CVP but negatively correlated with PaO2/FiO2 (r=-0.765, P<0.01), and positively correlated with PVPI (r=0.678, P<0.01). (4)Six patients died within 28 days. EVLWI of the dead patients were prominently higher at Tb and T4 than those of survived patients (both P<0.01), but the EVLWI gap (DeltaEVLWI) had no difference before and after resuscitation (P>0.05).

Conclusion: Fluid resuscitation in early stage of septic shock can improve ITBVI, GEDVI, CI, SI, CVP, with neither increased EVLWI nor worsened oxygenation. EVLWI has significantly negative correlation with PaO(2)/FiO(2) but not with haemodynamics. The increase in PVPI is responsible for the elevation of EVLWI. The patient's outcome is significantly correlated with the value of EVLWI.