The acute effectiveness and safety of the constant-flow, pressure-volume curve to improve hypoxemia in acute lung injury.

OBJECTIVE: To investigate the effectiveness of the constant-flow, pressure-volume curve (PVC) to prescribe positive end-expiratory pressure (PEEP) in acute lung injury (ALI) and risk of cardiopulmonary deterioration during the PVC process. DESIGN: A retrospective, cohort study. SETTING: A surgical intensive care unit (ICU) of a tertiary, university hospital. PATIENTS: Fifty consecutive ventilated patients diagnosed with ALI undergoing the PVC maneuver from 1999 to 2003. INTERVENTIONS: Titration of PEEP based on the lower inflection point of the constant-flow, pressure-volume curve. MEASUREMENTS AND MAIN RESULTS: Patients were divided into 2 groups based on PVC-guided PEEP changes of <3 cm H2O (PVC-NC or "no change") or ≥3 cm H2O (PVC-CHG or "change") from the initial empiric prescription. There was a greater increase in partial pressure of arterial oxygen (PaO2)/fractional concentration of inspired oxygen (FiO2) in the PVC-CHG group, with a mean change of 80 ± 50 (95% confidence interval [CI] 61, 98) versus 42 ± 54 (95% CI 17, 67) in the PVC-NC group. Eighty-two percent of patients (41/50) showed an increase in ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) by 20% within 6 to 24 hours after the PVC test-greater in the PVC-CHG group (OR 1.44, 95% CI 1.02, 2.01). Thirteen percent (4/30) within the PVC-CHG group and none within the PVC-NC group (0/20) required a 25% increase in vasoactive infusion rates (P = .089) in relation to the procedure. Univariate logistic regression showed that PVC-CHG was significantly associated with a 20% change in PaO2/FiO2 (OR 7.54, 95% CI 1.37, 41.41). Multivariate logistic modeling showed that PVC-guided PEEP changes of ≥3 cm H2O, age ≤65 years, and pre-PVC FiO2 ≥ .85 were significantly associated with a 20% increase in PaO2/FiO2 (receiver operator area under the curve = .86). CONCLUSIONS: In the setting of acute lung injury, use of the constant-flow, pressure-volume curve to prescribe PEEP appears associated with improvement in oxygenation with limited risk of acute, process-related, cardiopulmonary deterioration.

Reduced mortality with noninvasive hemodynamic monitoring of shock.

PURPOSE: This study compared clinical outcomes associated with exposure to pulmonary artery catheters (PACs), central venous catheters (CVCs), arterial pressure waveform analysis for cardiac output (APCO), or no central monitoring (NCM) in patients with shock. MATERIALS AND METHODS: We assessed 6929 consecutive patients from 2003 to 2006 within a surgical intensive care unit of a university hospital, identifying 237 mechanically ventilated patients with shock. RESULTS: Adjusted for severity of illness, use of APCO monitoring, compared with other options, was associated with reduced intensive care unit mortality (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.18-0.77) and 28-day mortality (OR, 0.43; 95% CI, 0.22-0.85). Other monitors were not associated with changes of 28-day mortality (CVC: OR, 0.63; 95% CI, 0.34-1.17; PAC: OR, 0.78; 95% CI, 0.36-1.69) or were associated with increased risk (NCM: OR, 2.29; 95% CI, 1.14-4.61). There were significant differences in the fluid and vasoactive drug prescriptions among the groups. CONCLUSIONS: This study supports an association between the use of APCO monitoring and reduction in mortality in shock compared with traditional methods of monitoring. Although it is impossible to exclude the role of unrecognized/unrecorded differences among the groups, these findings may result from differences in supportive care, directed by monitor technology.