Articles: general-anesthesia.
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Anesthesia and analgesia · Aug 1995
Large tidal volume ventilation does not improve oxygenation in morbidly obese patients during anesthesia.
Eight morbidly obese patients (body mass index [BMI] = 46) were studied during general anesthesia and controlled mechanical ventilation. To evaluate the effect of large tidal volume ventilation on oxygenation and ventilation, the baseline 13 mL/kg tidal volume (VT) (calculated by the ideal body weight) was increased in 3 mL/kg volume increments to 22 mL/kg, while ventilatory rate (RR) and inspiratory time (TI) were kept constant. Each volume increment was maintained for 15 min. ⋯ Peak inspiratory airway pressure (Ppeak), end-inspiratory airway pressure (Pplateau), and compliance of the respiratory system (CRS) were recorded using the Capnomac Ultima (Datex, Helsinki, Finland) on-line respiratory monitor. Increasing tidal volumes to 22 mL/kg increased the recorded Ppeak (26.3 +/- 4.1 vs 37.9 +/- 3.2 cm H2O, P < 0.008), Pplateau (21.5 +/- 3.6 vs 27.7 +/- 4.3 cm H2O, P < 0.01), and CRS (39.8 +/- 7.7 vs 48.5 +/- 8.3 mL/cm H2O) significantly without improving arterial oxygen tension and resulted in severe hypocapnia. Since changes in arterial oxygenation were small and not statistically significant, mechanical ventilation of morbidly obese patients with large VTS seems to offer no advantage to smaller (13 mL/kg ideal body weight) VTS.
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Anesthesia and analgesia · Aug 1995
The effect of changing end-expiratory pressure on respiratory system mechanics in open- and closed-chest anesthetized, paralyzed patients.
The decrease in functional residual capacity (FRC) with anesthesia may cause lung volume to decrease below closing volume, thereby impairing oxygenation. Increasing end-expiratory pressure (EEP) reexpands atelectatic areas in anesthetized, ventilated patients, but its effect on pulmonary mechanics is less well understood. We studied the effect of varying EEP on the mechanical behavior of the respiratory system in patients undergoing either closed (Group 1) or open-chest (Group 2) surgical procedures. ⋯ The magnitudes of RRS and RL were similar in both groups of subjects and in each group these quantities decreased with increases in EEP. Dynamic EL responded differently to changes in EEP in subjects with open-chest and closed-chest procedures. We attribute this difference to overdistension of the remaining ventilable lung tissue at all levels of EEP in open-chest patients.
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To determine unbiased patient preferences for either spinal or general anesthesia for upcoming surgeries. ⋯ This survey shows a strong patient preference for general anesthesia and a phobia for spinal anesthesia.
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Comparative Study Clinical Trial
[The utility of thermistor attached tracheal tube for pediatric patients in cardiac surgery].
During cardiac surgery, esophageal, rectal, or bladder temperature is usually monitored as an index of core temperature; however, these methods are invasive, and often inconsistently reflect the central body temperature, especially in pediatric patients. The purpose of this study was to evaluate the utility of tracheal temperature monitoring during cardiac surgery in pediatric patients. Fifteen children (ages; 8 m.-7 yr.) undergoing cardiac surgery with cardio-pulmonary bypass (CPB) were studied. ⋯ There were also good correlations of the esophageal as well as bladder temperatures with blood temperature. There were no patients who suffered tracheal inflammation or laryngeal edema from the thermistor. Monitoring tracheal temperature is not only valuable for monitoring the core temperature, but also is convenient for pediatric patients in cardiac surgery.
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Implantable cardioverter defibrillator implantation is performed under general anaesthesia. This report describes awareness or recall in two of 33 patients scheduled for implantation. ⋯ In these two patients propofol flowed out of the bleeding central venous access. To minimise the possibility of awareness, we advise that continuous infusions should be administered intravenously on the contralateral side to the implantation and that neuromuscular blocking agent be given by intermittent bolus injections.