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ABSTRACT: The intubating laryngeal mask airway (ILMA) is designed to facilitate blind tracheal intubation. The effect of a muscle relaxant on the ability to perform tracheal intubation through the ILMA device has not been previously evaluated. This randomized, double-blind, placebo-controlled study was designed to evaluate rocuronium, 0.2 or 0.4 mg/kg administered intravenously, on the success rate and incidence of complications associated with ILMA-assisted tracheal intubation.
A total of 75 healthy patients were induced with propofol 2 mg/kg and fentanyl 1 microg/kg intravenously. After insertion of the ILMA device, patients were administered either saline, rocuronium 0.2 mg/kg, or rocuronium 0.4 mg/kg in a total volume of 5 ml. At 90 s after administration of the study drug, tracheal intubation was attempted using a disposable polyvinyl tube. If unsuccessful, a reusable silicone tube was tried. In addition to recording the time and number of attempts required to secure the airway, the incidence of complications during placement of the tracheal tube and removal of the ILMA were noted.
Tracheal intubation was successful in 76-96% of the patients. The overall success rates and times required to secure the airway were similar in all three treatment groups. The high-dose rocuronium group experienced less patient movement (8 vs. 28 and 48%) and coughing (12 vs. 20 and 52%) than the low-dose rocuronium and saline groups, respectively. Use of rocuronium was also associated with a dose-related decrease in the requirement for supplemental bolus doses of propofol during intubation and removal of the ILMA device.
Use of rocuronium did not significantly improve the success rate in performing tracheal intubation through the ILMA. However, it produced dose-related decreases in coughing and movement after tracheal intubation and reduced difficulties associated with removal of the ILMA device.
Anesthesiology 09/2000; 93(2):340-5. · 5.36 Impact Factor
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ABSTRACT: The cuffed oropharyngeal airway is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this study were to compare the ability of the cuffed oropharyngeal airway and the laryngeal mask airway to provide positive-pressure ventilation during general anesthesia, and to assess their relative ease of use and ability to reduce total fresh gas flow rates.
In this prospective, randomized study, a cuffed oropharyngeal airway (n = 25) or a laryngeal mask airway (n = 25) device was inserted after induction of anesthesia intravenously using 2 mg/kg propofol. While anesthesia was maintained with sevoflurane and nitrous oxide, the leak pressure, leak fraction (the fractional difference between the inspired and expired tidal volume), minimum fresh gas flow rate, and need for airway manipulations were determined. The anesthesia provider who inserted the device completed an evaluation form at the end of the 15-min study period.
Positive-pressure ventilation was established successfully on the first attempt in 92% of the patients when the cuffed oropharyngeal airway was used and in 88% of the patients when the laryngeal mask airway device was used. However, manipulations of the airway device were necessary more frequently (8 vs. 1 patient; P < 0.05) and the leak pressure was less (22 +/- 6 cm water vs. 26 +/- 5 cm water; P < 0.05) with the cuffed oropharyngeal airway than with the laryngeal mask airway. In addition, the leak fraction (0.19 +/- 0.18 vs. 0.31 +/- 0.22; P < 0.05) and the minimum fresh gas flow rate (1.3 +/- 1.5 vs. 2.4 +/- 2.5; P = 0.12) were less in the laryngeal mask airway group.
Positive-pressure ventilation is possible with the laryngeal mask airway and cuffed oropharyngeal airway devices. Although the cuffed oropharyngeal airway can be inserted easily by inexperienced users with a high first-attempt success rate (> 90%), manipulations of the device may be required to maintain a patent airway. The laryngeal mask airway device allows positive-pressure ventilation at slightly greater peak inspiratory pressures.
Anesthesiology 05/1999; 90(5):1306-10. · 5.36 Impact Factor
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ABSTRACT: Women awaiting needle-guided breast biopsy procedures may experience high anxiety levels. A randomized, double-blind, placebo-controlled study was designed to evaluate the ability of midazolam and diazepam (in a lipid emulsion [Dizac]) to improve patient comfort during needle localization and breast biopsy procedures.
Ninety women received two consecutive doses of a study medication, one before the mammographic needle localization and a second before entering the operating room. Patients were assigned randomly to receive saline, 2.0 ml intravenously, at the two time points; midazolam, 1.0 mg intravenously and 2.0 mg intravenously; or diazepam emulsion, 2.0 mg intravenously and 5.0 mg intravenously, respectively. Patients assessed their anxiety levels before the needle localization, before entering the operating room, and on arrival in the operating room. Patients completed a questionnaire evaluating their perioperative experience at the time of discharge.
Patient satisfaction during needle localization was significantly improved in both benzodiazepine treatment groups (vs. saline). The incidence of moderate-to-severe discomfort during needle localization was lower in the midazolam (20%) and diazepam emulsion (6%) groups compared with the saline group (70%) (P<0.05). The preoperative visual analogue scale anxiety scores were similar in all three groups. In the operating room, however, anxiety scores were 55% and 68% lower after midazolam (21+/-19) and diazepam emulsion (15+/-14) compared with saline (46+/-28). Finally, there was no difference in the time to achieve home-readiness or actual discharge time among the three groups.
Premedication with midazolam or diazepam emulsion improved patients' comfort during needle localization procedures and significantly reduced intraoperative anxiety levels before breast biopsy procedures without prolonging discharge times. Use of diazepam emulsion may be an effective alternative to midazolam in this population.
Anesthesiology 03/1999; 90(3):740-7. · 5.36 Impact Factor
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ABSTRACT: Fast-tracking in the ambulatory setting refers to the ability to transfer suitably recovered patients from the operating room directly to the Phase II (step-down) recovery area, bypassing the postanesthesia care unit. This article describes the concept of fast-tracking after ambulatory surgery and reviews anesthetic techniques that have helped to facilitate this process. The prevention and management of postoperative pain and nausea are also discussed.
Current Opinion in Anaesthesiology 01/1999; 11(6):607-13. · 2.21 Impact Factor
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ABSTRACT: Impaired parasympathetic control of heart rate is associated with increased incidence of cardiac dysrhythmias and ischemia. Anticholinergic drugs suppress parasympathetic control and could be detrimental in the early postoperative period in high-risk patients. In this double-blind randomized trial, 30 ASA physical status I and II patients undergoing minor surgery received either atropine 20 micrograms/kg and neostigmine 50 micrograms/kg (Group A), glycopyrrolate 8 micrograms/kg and neostigmine 50 micrograms/kg (Group G), or placebo (Group P) for reversal of neuromuscular blockade. Two indices of parasympathetic modulation of heart rate, spontaneous baroreflex sensitivity, and high-frequency heart rate variability, were assessed. At 2 h after reversal, Group A showed persisting impairment of baroreflex sensitivity with respect to Group P (7.12 +/- 0.86 vs 12.71 +/- 1.38 ms/mm Hg, P = 0.022) as well as decreased high-frequency heart rate variability (280.8 +/- 30.1 vs 569.2 +/- 115.2 ms2/Hz, P = 0.015). Groups A and G showed a borderline decrease in normalized high-frequency variability at 2 h (P = 0.05 for Groups A and G versus Group P). Anticholinergic drugs with neostigmine cause impairment of parasympathetic control of heart rate which persists into the early postoperative period. The effects of glycopyrrolate appear to be of shorter duration; this drug may thus be preferable in patients at risk of cardiovascular complications.
Anesthesia & Analgesia 02/1997; 84(1):148-54. · 3.29 Impact Factor
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ABSTRACT: Impaired parasympathetic control of heart rate is associated with increased incidence of cardiac dysrhythmias and ischemia. Anticholinergic drugs, commonly administered during reversal of neuromuscular blockade, suppress parasympathetic control in the early postoperative period. This could potentially be detrimental in patients at risk of cardiovascular complications. The duration of parasympathetic impairment by two anticholinergic drugs were compared in this double-blind randomized cross-over study. Fourteen healthy volunteers received a single intravenous injection of atropine 20 micrograms/kg or glycopyrrolate 8 micrograms/kg during two different study sessions. The methods of spontaneous baroreflex analysis and spectral analysis of heart rate variability generated indices of beat-by-beat parasympathetic modulation of heart rate. Both drugs resulted in a marked decrease in baroreflex sensitivity and high-frequency heart rate variability. The times to return to baseline values were approximately doubled after atropine compared to glycopyrrolate (177 +/- 22 vs 82 +/- 8 min for baroreflex sensitivity, 212 +/- 16 vs 111 +/- 14 min for high-frequency power, and 171 +/- 18 vs 95 +/- 18 min for high-frequency power normalized to total power; P < 0.01 for all variables). Atropine leads to more prolonged impairment of parasympathetic control than equipotent doses of glycopyrrolate, and its use may thus be less desirable in high-risk patients in the early postoperative period.
Anesthesia & Analgesia 01/1997; 84(1):155-9. · 3.29 Impact Factor
