Impact of endotracheal tube size on preextubation respiratory variables.

PURPOSE: Many parameters have been evaluated to predict successful extubation. These are all affected by extrapulmonary variables. The purpose of this study was to evaluate the effect of endotracheal tube (ETT) size on preextubation predictors of successful extubation. MATERIALS AND METHODS: Twenty-two intubated and mechanically ventilated subjects were recruited when ready for extubation. Subjects were ventilated with T-piece, continuous positive airway pressure (CPAP) of 5 cm H(2)O, and pressure support ventilation (PSV) of 5 cm H(2)O in randomized order for 15 minutes each. Pulmonary mechanics-including respiratory frequency (f), tidal volume (V(T)), f/V(T) ratio, negative change in esophageal pressure, pressure time product (PTP), work of breathing, and the airway occlusion pressure 100 milliseconds after the onset of inspiratory flow-were measured using a microprocessor-based monitor at the end of each interval. After extubation, measurement of pulmonary mechanics was repeated at 15 and 60 minutes. RESULTS: In patients with 7.0- or 7.5-mm ETT compared with patients with 8.0-mm ETT, (1) f was significantly higher during all ventilatory modes and 15 minutes after extubation; (2) V(T) during PSV and CPAP was significantly lower; (3) mean f/V(T) was significantly higher (122 ± 57 vs 69 ± 35, P = .026); and (4) PTP was significantly higher during CPAP, PSV, and 15 minutes after extubation. There was a nonsignificant trend toward increased negative change in esophageal pressure, work of breathing, and airway occlusion pressure 100 milliseconds after the onset of inspiratory flow in the smaller-ETT group. CONCLUSIONS: The ETT size has a significant impact on f, V(T), f/V(T) ratio, and PTP.

Clinical benefits of neoral C2 monitoring in the long-term management of renal transplant recipients.

BACKGROUND: Cyclosporine monitoring using the 2-hr postdose sample, C2, has been shown to have advantages in monitoring de novo renal transplant recipients. The purpose of this study was to assess cyclosporine exposure, using C2, in stable renal transplant patients previously monitored by C0 to determine the effect of dose reduction on patients with C2 more than 10% above target and the course of those with C2 at and more than 10% below target, whose dose was not modified. METHODS: One hundred and seventy-five patients, three or more months after transplantation, had C2 assessed. The relationship of C2 to C0 and of both to renal function was analyzed by linear regression. Blood pressure, serum creatinine level, and lipids were followed for a mean of 15+/-2.6 months. RESULTS: Eighty-five patients had values more than 10% above target, 42 were within 10% of target, and 48 were more than 10% below target. Cyclosporine dose was reduced in all patients above target. In this group, serum creatinine level was stable overall, but fell significantly in 46 (54%) of 85 from 153+/-55 to 132+/-49 microM. Blood pressure also fell in that group from 135/82 to 131/77. Serum creatinine level was stable in the remaining two groups of patients. CONCLUSIONS: These data suggest that dose reduction in many overexposed patients leads to improvements in renal function and blood pressure. Further study is required to confirm the long-term benefits of this strategy.