Are changes in the evoked electromyogram during anaesthesia without neuromuscular blocking agents caused by failure of supramaximal nerve stimulation?
(1/79)
The evoked electromyogram often decreases during anaesthesia in the absence of neuromuscular block. We have measured the electromyogram of the first dorsal interosseous muscle evoked by train-of-four stimulation of the ulnar nerve in 63 patients undergoing anaesthesia for minor surgery. We used Medicotest P-00-S electrodes, a Datex Relaxograph and a current sink in the stimulating leads in parallel with the current path through the patient. The current sink was used to shunt some of the maximum available output current from the Relaxograph while maintaining the supramaximal stimulus current passing through the patient. After 30 min of anaesthesia, when the muscle response to train-of-four was stable, the ulnar nerve stimulus current was increased by reducing the proportion shunted through the current sink. The electromyographic response did not change during the study in 13 patients. In the remaining 50 patients, the response decreased to 78.4% (SD 27.1%, range 7.5-95.0%) of baseline values over the first 20 min of anaesthesia. In 22 of these patients, the electromyographic response increased from 71.4 (SD 22.6)% to 92.3 (9.5)% of baseline responses when the stimulus current was increased by 12.3 (2.4) mA, while in the remaining 28 patients the response decreased to 83.7 (10.6)% and did not increase with increasing stimulus current. These results suggest that loss of supramaximal stimulation is partly responsible for the observed changes in the evoked electromyogram during anaesthesia. (+info)
Serum myoglobin and creatine kinase following surgery.
(2/79)
Serum myoglobin (by radioimmunoassay) and creatine kinase were measured for up to 7 days in 30 patients following surgical procedures, including total hip replacement and bilateral subcostal abdominal incisions. Serum myoglobin reached a maximum of 1390 micrograms litre-1 (median 345 micrograms litre-1 for major surgery patients) on the first postoperative day but levels were still elevated by day 7 in some patients. Creatine kinase reached a maximum of 1339 i.u. litre-1 at day 2 (median 422 i.u. litre-1 for major surgery patients), generally peaking 1 day after myoglobin in individual patients. These values may have significance when investigating a suspicion of coincident perioperative events such as myocardial infarction or malignant hyperthermia. (+info)
A pilot randomised controlled trial of medical versus nurse clerking for minor surgery.
(3/79)
BACKGROUND: Nurse led clerking is currently practiced in a growing number of UK centres, but there is a paucity of evidence to underpin the safety of this innovation. AIM: To assess the safety of nurse led clerking in paediatric day case and minor surgery. METHODS: Children aged 3 months to 15 years were randomly assigned to clerking by either a nurse or a senior house officer (SHO) (resident). All children were then independently reassessed by a specialist registrar anaesthetist to provide a "gold standard" against which practitioner performance could be judged. RESULTS: In 60 children studied, nurses identified a significantly greater proportion of the detectable abnormalities present in the sample (p = 0.16). This difference is attributable to nurses' greater accuracy in history taking (p = 0.04); no conclusions regarding the comparability of nurses' and SHOs' skills in physical examination can be derived from the current study. CONCLUSION: Evidence attests to the likelihood of nursing having superior skills in history taking to SHOs. Exploration of nursing safety in undertaking physical examination, however, requires the conduct of a large scale equivalence study. Only then can conclusions be drawn as to whether nurse led physical assessment offers children a standard of care equivalent to that which they currently receive from SHOs. (+info)
Wrist arthroscopy without distraction. A technique to visualise instability of the wrist after a ligamentous tear.
(4/79)
We describe a technique for arthroscopy of the wrist which is carried out without traction and with the arm lying horizontally on the operating table. The wrist is not immobilised, which makes it possible to assess the extent of instability after a ligamentous tear. In a prospective study of 30 patients we compared this technique with conventional wrist arthroscopy, performing the new method first followed by conventional arthroscopy. The advantages are that the horizontal position of the arm allows the surgeon to proceed directly from arthroscopic diagnosis to treatment, and that no change of position is required for fluoroscopy. In terms of diagnostic sensitivity, we found our technique matched that of conventional arthroscopy. We had no difficulty in carrying out minor surgical procedures such as debridement and suturing. (+info)
Effects of minor surgery and endotracheal intubation on postoperative breathing patterns in patients anaesthetized with isoflurane or sevoflurane.
(5/79)
We studied the effects of minor surgery and endotracheal intubation on postoperative breathing patterns. We measured breathing patterns and laryngeal resistance during the periods immediately before intubation (preoperative) and immediately after extubation following minor surgery (postoperative) in eight patients anaesthetized with sevoflurane and eight patients anaesthetized with isoflurane, breathing spontaneously through a laryngeal mask airway at a constant end-tidal anaesthetic concentration (1.0 MAC). In both sevoflurane-anaesthetized and isoflurane-anaesthetized patients, expiratory time was reduced and inspiratory and expiratory laryngeal resistance increased after surgery. In sevoflurane-anaesthetized patients, occlusion pressure (P0.1) increased without changes in inspiratory time (T(I)). Occlusion pressure did not change and T(I) was greater in isoflurane-anaesthetized patients after surgery. Minor surgery may have a small but significant influence on breathing and increased laryngeal resistance following endotracheal intubation may modulate these changes. The difference in breathing pattern between sevoflurane and isoflurane may be a result of different responses of the central nervous system to different anaesthetics in the presence of increased laryngeal resistance. (+info)
Comparison of caudal and intravenous clonidine in the prevention of agitation after sevoflurane in children.
(6/79)
BACKGROUND: In children, sevoflurane anaesthesia is associated with postanaesthetic agitation, which is treated mainly with opioids. We compared the effectiveness of epidural and i.v. clonidine in the prevention of this postanaesthetic agitation. METHODS: Eighty children aged 3-8 yr (ASA I-II) received standardized general anaesthesia with inhaled sevoflurane and caudal epidural block with 0.175% bupivacaine 1 ml kg-1 for minor surgery. The children were assigned randomly to four groups: (I) clonidine 1 microgram kg-1 added to caudal bupivacaine; (II) clonidine 3 micrograms kg-1 added to caudal bupivacaine; (III) clonidine 3 micrograms kg-1 i.v. and caudal bupivacaine; and (IV) caudal block with bupivacaine, no clonidine (control). A blinded observer assessed the behaviour of the children during the first postoperative hour. Secondary end-points were the time to fitness for discharge from the postanaesthesia care unit, and haemodynamic and respiratory variables. RESULTS: The incidence of agitation was 22, 0, 5 and 39% in groups I, II, III and IV respectively (P < 0.05 for groups II and III compared with group IV). During the first hour after surgery, patients in groups II and III had significantly lower scores for agitation than group IV patients. Time to fitness for discharge did not differ between the four groups. CONCLUSIONS: Clonidine 3 micrograms kg-1 prevented agitation after sevoflurane anaesthesia, independently of the route of administration. The effect of clonidine appears to be dose-dependent, as an epidural dose of 1 microgram kg-1 failed to reduce it. (+info)
A single preoperative oral dose of valdecoxib, a new cyclooxygenase-2 specific inhibitor, relieves post-oral surgery or bunionectomy pain.
(7/79)
BACKGROUND: The trend toward day-case surgery, with discharge on oral medication, has highlighted the need for effective and safe analgesics that facilitate a rapid recovery and discharge time. This study evaluated the analgesic efficacy, dose dependency, duration of action, and safety of the cyclooxygenase-2 specific inhibitor, valdecoxib, administered before oral or orthopedic surgery. METHODS: Eligible healthy adult patients were scheduled to undergo either extraction of two impacted third molar teeth (n = 284) or bunionectomy surgery (n = 223) with local anesthesia in two randomized, double-blind, placebo-controlled studies conducted at three centers in the United States. Patients received a single, preoperatively administered oral dose of placebo or 10 (oral surgery only), 20, 40, or 80 mg valdecoxib. Analgesic efficacy was assessed postoperatively, over a 24-h treatment period, or until the patient required rescue medication. Efficacy measures included time to rescue medication, proportion of patients requiring such rescue, pain intensity, and the Patient's Global Evaluation of Study Medication. RESULTS: In both studies, all doses of valdecoxib produced analgesia with a duration (time to rescue analgesia) and magnitude (Pain Intensity, Patient's Global Evaluation) significantly greater than placebo. A dose-dependent effect was observed up to 40 mg valdecoxib, with an 80-mg dose providing no additional analgesic benefit. In both models, all doses of valdecoxib were well tolerated, with no clinically significant treatment-related gastrointestinal, renal, or platelet-derived adverse events, and no evidence of a dose-related increase in adverse events. CONCLUSIONS: Preoperative orally administered valdecoxib provides well-tolerated and effective analgesia for mild to moderate postoperative pain. (+info)
Post-operative depression of antibody-dependent lymphocyte cytotoxicity following minor surgery and anaesthesia.
(8/79)
Leucocytes taken 1 day post-operatively from patients who had undergone surgery under general anaesthesia for benign breast disease showed a significantly diminished capacity to induce lysis of antibody-coated target cells compared with those taken pre-operatively from the same patients. No significant fall in PHA responsiveness was observed in these leucocytes in the post-operative period. This indicates a high sensitivity of the cell types involved in the antibody-dependent cell-mediated cytotoxicity reaction to the suppressive effect of surgery and anaesthesia. Plasmas taken post-operatively from these patients were effective in diminishing the capacity of leucocytes from healthy untreated donors to initiate antibody-coated target cell lysis compared with pre-operative plasmas although the plasma cortisol levels in these samples did not differ significantly. Possible mediators of this suppressive effect and its significance are discussed. (+info)