To study the effect of positive airway pressure (Paw) on the pressure gradient for venous return [the difference between mean systemic filling pressure (Pms) and right atrial pressure (Pra)], we investigated 10 patients during general anesthesia for implantation of defibrillator devices. Paw was varied under apnea from 0 to 15 cmH(2)O, which increased Pra from 7.3 +/- 3.1 to 10.0 +/- 2.3 mmHg and decreased left ventricular stroke volume by 23 +/- 22%. Episodes of ventricular fibrillation, induced for defibrillator testing, were performed during 0- and 15-cmH(2)O Paw to measure Pms (value of Pra 7.5 s after onset of circulatory arrest). Positive Paw increased Pms from 10.2 +/- 3.5 to 12.7 +/- 3.2 mmHg, and thus the pressure gradient for venous return (Pms - Pra) remained unchanged. Echocardiography did not reveal signs of vascular collapse of the inferior and superior vena cava due to lung expansion. In conclusion, we demonstrated that positive Paw equally increases Pra and Pms in humans and alters venous return without changes in the pressure gradient (Pms - Pra).

In patients with early extrapulmonary adult respiratory distress syndrome who underwent a PEEP trial, recruitment maneuvers failed to induce a sustained improvement of oxygenation and venous admixture.

SummaryIn a prospective, randomised trial, 75 patients scheduled for routine surgery were randomly allocated to one of three groups to evaluate trauma and postoperative complications after insertion of the Combitube, tracheal tube or laryngeal mask airway. Insertion of the Combitube was associated with a higher incidence of sore throat (48% vs. 16% vs. 12% [p < 0.01]) and dysphagia (68% vs. 12% vs. 8% [p < 0.01]) compared with tracheal intubation or insertion of the laryngeal mask airway, respectively. Hoarseness was significantly less common in both the Combitube and the laryngeal mask groups (both 12%) than in the tracheal tube group (44%; p < 0.01). Haematoma occurred in 36% of the Combitube group compared with 4% in both the laryngeal mask and the tracheal tube groups (p < 0.01). The higher incidence of complications should be considered when using the Combitube.

In patients undergoing cardiac surgery the monitoring of pre- and immediate postoperative HLA-DR levels during the first 24 h does not help to predict increased risk for postoperative SIRS/sepsis or infectious complications.

In this study, we showed that the hemodynamic and catecholamine stress responses after insertion of the Combitube (Kendall-Sheridan Catheter Corp., Argyle, NY) were significantly higher compared with laryngeal mask airway or endotracheal intubation. We conclude that the increased stress response to insertion of a Combitube may represent a serious hazard to patients with cardiovascular disease.