Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2002
The use of neuromuscular blocking drugs in adult cardiac surgery: results of a national postal survey.
Available data suggest that the choice of neuromuscular blocking drugs (NMBDs) can influence early clinical recovery of the fast-track cardiac surgical patient. The aim of this study was to use a survey tool to determine practice patterns of anesthesiologists for the use of NMBDs in the cardiac surgical setting. We mailed a survey to one third of the 3295 active members of the Society of Cardiovascular Anesthesiologists. A follow-up letter and survey were sent to each individual who did not respond to the initial mailing. After the second mailing, 459 surveys were returned, yielding a response rate of 43%. Pancuronium was listed as the primary NMBD used in the majority of patients undergoing cardiopulmonary bypass (69%) and off-pump (41%) procedures. Only 28% of respondents routinely used a peripheral nerve stimulator to monitor neuromuscular blockade in the operating room. Residual neuromuscular blockade was routinely reversed before tracheal extubation by only 9% of cardiac anesthesiologists. This survey demonstrates that long-acting NMBDs are often administered to fast-track cardiac patients. Peripheral nerve stimulator monitoring is rarely used in the operating room or intensive care unit, and reversal drugs (anticholinesterases) are infrequently administered in the postoperative period. ⋯ This postal survey of cardiac anesthesiologists demonstrates that long-acting muscle relaxants are frequently administered to fast-track cardiac surgical patients. Neuromuscular blockade is rarely monitored or reversed in this patient population.
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Anesthesia and analgesia · Dec 2002
Comparative StudyThe relationship between movement-evoked versus spontaneous pain and peak expiratory flow after abdominal hysterectomy.
The pathogenesis of postoperative lung dysfunction implies a role for movement-evoked pain (e.g., splinting/hypoventilation because of pain avoidance). However, interactions between evoked pain and respiratory physiology are poorly understood. Thus, we examined the relationship between evoked versus spontaneous pain and one index of pulmonary function. In 25 patients having undergone a hysterectomy, visual analog scale ratings (100 mm) for spontaneous pain (REST) and pain during sitting (SIT), forced expiration (BLOW), and coughing (COUGH) were measured together with peak expiratory flow (PEF) at eight time points during postoperative Days 1 and 2. Secondary outcome measures included oxygen saturation and oxygen requirements. Pain was significantly correlated with PEF for COUGH, SIT, BLOW, and REST at eight, seven, four, and two of the eight studied time points, respectively. Mean visual analog scale scores [SE] for COUGH (26.1 mm [1.7]) and SIT (21.5 mm [1.5]) were greater (P < 0.05) than REST (10.5 mm [0.8]), and COUGH was greater (P < 0.05) than BLOW (16.8 mm [1.3]). All pain measures diminished (P < 0.05), and PEF reductions improved (P < 0.05) across the study period. We hypothesize that the consistent negative correlation of COUGH-evoked pain with PEF is, in part, caused by avoidance of coughing, which ultimately limits deep inspiration, lung reexpansion, and clearance of secretions. ⋯ Movement-evoked pain may be an important contributor to postoperative complications, but its mechanisms are poorly understood. This study provides the first evidence that postoperative evoked pain correlates with lung function and highlights the need for future research on mechanisms and implications of this phenomenon.
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Clinical TrialThe effect of increased FIO(2) before tracheal extubation on postoperative atelectasis.
General anesthesia promotes pulmonary atelectasis, which can be eliminated by a vital capacity (VC) maneuver (inflation of the lungs to 40 cm H(2)O for 15 s). High-inspired oxygen concentration favors recurrence of atelectasis. Therefore, 100% oxygen before tracheal extubation may contribute to atelectasis. To evaluate whether the use of 100% oxygen before extubation increases the amount of postoperative atelectasis, we studied 30 adults scheduled for elective surgery of the extremities. Ten minutes before the presumed end of surgery, patients were randomly assigned to (a) a fraction of inspired oxygen (FIO(2)) = 1.0 (n = 10), (b) VC maneuver + FIO(2) = 1.0 (n = 10), or (c) VC maneuver + FIO(2) = 0.4 (n = 10). The amount of atelectasis was measured by computed tomography scan, and oxygenation was studied by arterial blood gas analysis. Data were analyzed by one-way analysis of variance with Bonferroni correction. Results are presented as mean +/- SD; P < 0.05 was considered significant. In the VC maneuver + FIO(2) = 0.4 group, postoperative atelectasis was smaller (2.6% +/- 1.1% of total lung surface, P < 0.05) than in the FIO(2) = 1.0 group (8.3% +/- 6.2%) and in the VC maneuver + FIO(2) = 1.0 group (6.8% +/- 3.4%). Oxygen 100% at the end of general anesthesia promotes postoperative atelectasis. A safety margin in terms of oxygenation during tracheal extubation is essential, and further studies should therefore evaluate whether atelectasis formation could be prevented despite the use of 100% oxygen. ⋯ For safety reasons, it is common to ventilate patients with 100% oxygen before tracheal extubation. This study demonstrates that this practice favors postoperative atelectasis.
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of ketamine and lidocaine spray with propofol for the insertion of laryngeal mask airway in children: a double-blinded randomized trial.
The laryngeal mask airway (LMA) has been used successfully as both a ventilatory device and a conduit for tracheal intubation. In this double-blinded, randomized study, we examined whether pretreatment with lidocaine spray, ketamine anesthesia, and LMA insertion could be used as airway management that could maintain spontaneous breathing in children. After IV premedication with midazolam 0.05 mg/kg and glycopyrrolate 0.005 mg/kg, 90 patients were randomly allocated to 1 of 2 main groups for the administration of either propofol or ketamine: 40 patients received 2.5, 3.0, 3.5, or 4.0 mg/kg of propofol IV (n = 10 each), whereas 50 patients received 2.0, 2.5, 3.0, 3.5, or 4.0 mg/kg of ketamine IV (n = 10 each). Only in the ketamine group was lidocaine spray applied to the oropharynx 1 min before anesthesia induction. After injection of the designated drug, self-respiration, airway obstruction, and jaw relaxation were checked. Self-respiration, laryngospasm coughing, gagging, swallowing, biting or tongue movements, secretions, and head or limb movements after LMA insertion were graded. All variables were graded as satisfactory, acceptable, or unsatisfactory. The overall result was considered satisfactory if all criteria were satisfactory; acceptable if all were better than acceptable, but at least one acceptable criterion was included; and unsatisfactory if at least one criterion was unsatisfactory. Overall satisfactory or acceptable results in every patient were achieved only in the ketamine 3.0 or 3.5 mg/kg subgroups. No propofol dose was completely satisfactory; most cases involved apnea or airway obstruction. Ketamine and lidocaine spray were appropriate for LMA insertion, which may be a safe method for management of difficult airway in children. ⋯ Ketamine and lidocaine spray appear to be appropriate for laryngeal mask airway (LMA) insertion in children. Thus, apnea and airway obstruction, the two most serious and frequent complications of propofol, can be avoided during LMA insertion.
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Anesthesia and analgesia · Dec 2002
Randomized Controlled Trial Comparative Study Clinical TrialMinidose lidocaine-fentanyl spinal anesthesia in ambulatory surgery: prophylactic nalbuphine versus nalbuphine plus droperidol.
Minidose lidocaine-fentanyl spinal anesthesia (SAB(MLF)) is a safe, effective, and efficient anesthetic for ambulatory surgery. Unfortunately, it has a frequent incidence of pruritus and a substantial incidence of nausea and vomiting. Nalbuphine is effective in treating or preventing pruritus after intrathecal or epidural morphine but may or may not have a beneficial effect on nausea and vomiting. Droperidol has demonstrated antiemetic efficacy with neuraxial opiates. In this study, we examined the prophylactic use of nalbuphine alone compared with nalbuphine with droperidol after SAB(MLF). One-hundred-twenty-four patients having outpatient knee arthroscopy under SAB(MLF) with 20 mg of lidocaine 0.5% and 20 micro g of fentanyl were randomized to receive IV at the end of surgery either 4 mg of nalbuphine (Group N) or droperidol 0.625 mg plus nalbuphine 4 mg (Group ND). The incidences of early (before discharge) and late onset nausea were, respectively, 18% versus 5% and 32% versus 13%. The postoperative incidences of pruritus were 61% versus 40%, whereas 19% of patients in Group N compared with 2% of patients in Group ND requested treatment for this. Group ND had lower pain scores and had a longer delay until first use of analgesic. There were no differences in average times to discharge. The only side effect of the medications was an increased drowsiness in Group ND. In conclusion, as prophylactic medication for use in conjunction with SAB(MLF), the addition of droperidol 0.625 mg to nalbuphine 4 mg was superior to nalbuphine alone. The combination provided for reduced postoperative nausea, pruritus, and pain-benefits that persisted after discharge home. The combination also avoided isolated cases of extreme delay in discharge. ⋯ Droperidol in combination with nalbuphine enhances analgesia and is more effective than nalbuphine alone in preventing pruritus, nausea, and vomiting after minidose lidocaine-fentanyl spinal anesthesia.