Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2002
Randomized Controlled Trial Clinical TrialRapid deflation of the bronchial cuff of the double-lumen tube after decreasing the concentration of inspired nitrous oxide.
Deflationary phenomena of the endotracheal tube cuff may occur after inspired nitrous oxide (N(2)O) concentrations are reduced, but deflationary phenomena of the double-lumen tube (DLT) cuff have not been investigated. In this study, tracheal and bronchial cuffs of left-sided Mallinckrodt (Athlone, Ireland) DLTs were inflated with air, 40% N(2)O, or 67% N(2)O (Air, N40, or N67 groups, respectively) in 24 patients undergoing thoracic surgery; 40 min later, O(2) was substituted for N(2)O in some of the patients in the N40 group (N40-c group). Intracuff gas volumes, N(2)O concentrations, and cuff compliance were also measured. Both tracheal and bronchial cuff pressures significantly increased in the Air group but decreased in the N67 group. Neither pressure significantly changed in the N40 group, but both decreased in the N40-c group after terminating N(2)O anesthesia; the time required for bronchial cuff pressures to decrease by half (12.0 +/- 5.5 min) was less than that for tracheal cuff pressures (31.2 +/- 11.0 min, P < 0.01). The volume change in the N40-c group was not significantly different between the tracheal and bronchial cuffs, but tracheal cuff compliance was significantly higher than bronchial compliance. Therefore, filling DLT cuffs with 40% N(2)O stabilizes cuff pressure during anesthesia with 67% N(2)O, but bronchial cuffs deflate more quickly than tracheal cuffs after cessation of N(2)O administration through smaller compliance. ⋯ We demonstrated that after cessation of nitrous oxide (N(2)O) administration, bronchial N(2)O-filled cuffs of the double-lumen tube deflate more rapidly than tracheal cuffs. To avoid insufficient separation of the lungs by the bronchial cuff, a frequent check of the cuff pressure is recommended after the inspired N(2)O concentration is decreased.
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Anesthesia and analgesia · Jul 2002
Clinical TrialInsufficiency in a new temporal-artery thermometer for adult and pediatric patients.
SensorTouch is a new noninvasive temperature monitor and consists of an infrared scanner that detects the highest temperature on the skin of the forehead, presumably over the temporal artery. The device estimates core temperature (T(core)). We tested the hypothesis that the SensorTouch is sufficiently precise and accurate for routine clinical use. We studied adults (n = 15) and children (n = 16) who developed mild fever, a core temperature of at least 37.8 degrees C, after cardiopulmonary bypass. Temperature was recorded at 15-min intervals throughout recovery with the SensorTouch thermometer and from the pulmonary artery (adults) or bladder (children). Pulmonary artery (T(core)) and SensorTouch (T(st)) temperatures correlated poorly in adults: T(core) = 0.7. T(st) + 13, r(2) = 0.3. Infrared and pulmonary artery temperatures differed by 1.3 +/- 0.6 degrees C; 89% of the adult temperatures thus differed by more than 0.5 degrees C. Bladder and infrared temperatures correlated somewhat better in pediatric patients: T(core) = 0.9. T(st) + 12, r(2) = 0.6. Infrared and bladder temperatures in children differed by only 0.3 degrees C, but the SD of the difference was 0.5 degrees C. Thus, 31% of the values in the infants and children differed by more than 0.5 degrees C. ⋯ We evaluated a noninvasive infrared forehead thermometer (SensorTouch) in adult and pediatric cardiac patients. Accuracy was poor in the adults and suboptimal in infants and children.
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Anesthesia and analgesia · Jul 2002
Case ReportsThe use of the intubating laryngeal mask endotracheal tube with intubating devices.
Despite adequate visualization of the vocal cords using specialized airway devices, anatomical factors and the physical characteristics of the tube may cause difficulty when performing endotracheal intubation. The endotracheal tube designed for use with the intubating laryngeal mask airway may facilitate intubation in these circumstances.
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Anesthesia and analgesia · Jul 2002
Serum creatinine patterns in coronary bypass surgery patients with and without postoperative cognitive dysfunction.
Renal dysfunction is common after coronary artery bypass graft (CABG) surgery. We have previously shown that CABG procedures complicated by stroke have a threefold greater peak serum creatinine level relative to uncomplicated surgery. However, postoperative creatinine patterns for procedures complicated by cognitive dysfunction are unknown. Therefore, we tested the hypothesis that postoperative cognitive dysfunction is associated with acute perioperative renal injury after CABG surgery. Data were prospectively gathered for 282 elective CABG surgery patients. Psychometric tests were performed at baseline and 6 wk after surgery. Cognitive dysfunction was defined both as a dichotomous variable (cognitive deficit [CD]) and as a continuous variable (cognitive index). Forty percent of patients had CD at 6 wk. However, the association between peak percentage change in postoperative creatinine and CD (parameter estimate = -0.41; P = 0.91) or cognitive index (parameter estimate = -1.29; P = 0.46) was not significant. These data indicate that postcardiac surgery cognitive dysfunction, unlike stroke, is not associated with major increases in postoperative renal dysfunction. ⋯ We previously noted that patients with postcardiac surgery stroke also have greater acute renal injury than unaffected patients. However, in the same setting, we found no difference in renal injury between patients with and without cognitive dysfunction. Factors responsible for subtle postoperative cognitive dysfunction do not appear to be associated with clinically important renal effects.
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Anesthesia and analgesia · Jul 2002
Comparative Study Clinical TrialRepeated deflation of a gas-barrier cuff to stabilize cuff pressure during nitrous oxide anesthesia.
Although a nitrous oxide (N(2)O) gas-barrier cuff effectively limits the increase of cuff pressure during N(2)O anesthesia, there are few data assessing whether an N(2)O gas-barrier cuff is more beneficial for stabilizing intracuff pressure than standard endotracheal tubes when cuffs are repeatedly deflated to stabilize pressure during N(2)O anesthesia. In the present study, the pressure of air-filled standard-type cuffs (Trachelon; Terumo, Tokyo, Japan) and N(2)O gas-barrier type endotracheal tube cuffs (Profile Soft-Seal Cuff [PSSC]; Sims Portex, Kent, UK) was measured during 67% N(2)O anesthesia (n = 8 in each), during which the cuffs were repeatedly deflated every 30 min (Trachelon) or 60 min (PSSC) for the first 3 or 4 h. After aspirating the cuffs for 3 h, the cuff pressure exceeded 22 mm Hg in more than half of the patients in both groups. However, aspiration of the cuffs for 4 h decreased the maximal cuff pressure between deflation intervals in both groups (P < 0.01 for each), and increased the intracuff N(2)O concentration (P < 0.0001 for each). After deflating the cuffs over 4 h, the cuff pressure in both groups never exceeded 22 mm Hg during the subsequent 3 h, and intracuff N(2)O concentrations did not significantly change. Therefore, deflation of cuffs for 4 h during N(2)O anesthesia sufficiently stabilized cuff pressure and equilibrated the intracuff N(2)O concentrations in both groups. The use of the PSSC endotracheal tube might be more practical because of the smaller number of cuff deflations required, but the PSSC does not reduce the duration of cuff deflations to stabilize the pressure. ⋯ We demonstrated that the N(2)O concentration and pressure in the N(2)O-barrier Profile Soft-Seal Cuff stabilized when the cuff was aspirated once an hour for 4 h during N(2)O anesthesia. The Profile Soft-Seal Cuff might be easier to use in clinical practice than standard endotracheal tubes because of the smaller number of cuff deflations required.