Performance of the partial CO2 rebreathing technique under different hemodynamic and ventilation/perfusion matching conditions.

Objective: The partial CO2 rebreathing technique has been demonstrated to accurately measure the effective pulmonary capillary blood flow (PCBF) in different clinical situations. Usually, PCBF is calculated from changes in CO2 elimination (VCO2) and end-tidal partial pressure of CO2 (PetCO2 ), which can be obtained noninvasively. In this study, we investigated the performance of the partial CO2 rebreathing technique under different conditions of ventilation/perfusion matching and hemodynamic states.

One-lung ventilation with high tidal volumes and zero positive end-expiratory pressure is injurious in the isolated rabbit lung model.

Unlabelled: We tested the hypothesis that one-lung ventilation (OLV) with high tidal volumes (VT) and zero positive end-expiratory pressure (PEEP) may lead to ventilator-induced lung injury. In an isolated, perfused rabbit lung model, VT and PEEP were set to avoid lung collapse and overdistension in both lungs, resulting in a straight pressure-time (P-vs-t) curve during constant flow. Animals were randomized to (a) nonprotective OLV (left lung) (n = 6), with VT values as high as before randomization and zero PEEP; (b) protective OLV (left lung) (n = 6), with 50% reduction of VT and maintenance of PEEP as before randomization; and (c) control group (n = 6), with ventilation of two lungs as before randomization.

Evaluation of a new device for noninvasive measurement of nonshunted pulmonary capillary blood flow in patients with acute lung injury.

Objectives: To evaluate the performance of a new device for noninvasive measurement of nonshunted pulmonary capillary blood flow (PCBF) by partial CO2 rebreathing.

Design And Setting: Prospective clinical trial in an intensive care unit of a university hospital.

Patients And Participants: Twenty mechanically ventilated patients with acute lung injury.