Postoperative analgesia after peripheral nerve block for podiatric surgery: clinical efficacy and chemical stability of lidocaine alone versus lidocaine plus ketorolac.

BACKGROUND AND OBJECTIVES: The purpose of this study was to determine whether the addition of ketorolac tromethamine to local anesthesia for ankle block alters the quality or duration of analgesia after podiatric surgery. The second aim was to determine the chemical stability of ketorolac tromethamine when added to local anesthetic solutions. METHODS: The study design was double-blinded, placebo-controlled, and randomized. Seventy-nine American Society of Anesthesiologists (ASA) class I or II patients scheduled for bunionectomy or hammer toe repair, or both were randomized to 1 of 4 groups. Group L received plain 1.73% lidocaine for their ankle block. Group K received 1.73% lidocaine with ketorolac (4 mg/mL) added to the local solution. Group Kiv received 1.73% plain lidocaine for ankle block and 20 mg of ketorolac intravenously. Group E received 1.73% lidocaine with .67% ethanol added. The final concentration of lidocaine for all groups was 1.73%. The block performed in each patient was a 5-point ankle block. Beginning at 1 hour after the completion of the block and every 30 minutes thereafter, visual analogue scale (VAS) and verbal pain scores were recorded. The time from performance of the block to the initial pain and time to the first oral pain medication intake were also recorded. The time and amount of postoperative oral analgesics in the first 9 hours after the block were recorded. Adverse events were also recorded for each group. RESULTS: There were significantly lower overall VAS and verbal pain scores for group K compared with groups E and L and group Kiv compared with group E. Group K also had a significantly longer time to the first reported pain and first oral pain medications than groups E and L, but not with Group Kiv. The same group had significantly fewer average doses of pain medications postoperatively than Groups E and L. Group E had significantly shorter times to first report of pain and first pain medications and higher mean dose of postoperative oral analgesics than group K and Group Kiv. There were no untoward side effects reported from any group. Chemical analysis by gas chromatography (GC) and capillary electrophoresis (CE) showed no significant change in composition of the solutions when ketorolac was mixed with lidocaine and/or bupivacaine and stored at 37 degrees C for 1 week. CONCLUSIONS: The addition of ketorolac to lidocaine for ankle block contributed to longer duration and better quality analgesia after foot surgery compared with plain 1.73% lidocaine or 1.73% lidocaine plus intravenous ketorolac. The ethanol vehicle is unlikely responsible for the analgesic effects of ketorolac. Ketorolac retains its chemical stability when placed in local solutions of lidocaine or bupivacaine.

Transdermal fentanyl system plus im ketorolac for the treatment of postoperative pain.

PURPOSE: To assess the safety and efficacy of transdermal fentanyl plus im ketorolac vs im ketorolac alone in the treatment of postoperative pain. METHODS: Ninety-two patients scheduled for surgery involving moderate to severe postoperative pain were randomized to one of two groups. Group A (n = 46) received an active fentanyl patch and group P (n = 46) received a placebo patch. Patches remained in place for 24 hr. Each patient received intraoperative ketorolac, 60 mg im. Patients were monitored for 36 hr postoperatively and the groups were analyzed for ketorolac usage, pain scores, vital signs, serum fentanyl concentrations, and adverse events. Intramuscular ketorolac was available on demand. RESULTS: Group A had lower pain scores at 8.12, 16 and 24 hr after patch placement (P < 0.05). Group A had lower heart rates, lower respiratory rates and fewer dropouts due to inadequate pain relief (4.3% vs 21.7% P < 0.05). Group A patients also used less ketorolac than group P patients (P < 0.05). The incidence of pruritus was higher in group A patients (19% vs 2%, P < 0.05), while the incidence of nausea and vomiting was not different between the two groups. Transdermal fentanyl was adequate "stand-alone" analgesia in only 23.8% of group A patients while 93.7% of the remaining group A patients receiving a combination of transdermal fentanyl and ketorolac had adequate pain relief. CONCLUSION: The transdermal fentanyl delivery system plus ketorolac im was more effective in controlling post-operative pain than ketorolac im alone. The two treatment modalities were comparable in safety with no difference in serious adverse events.

Outpatient general anesthesia: a comparison of a combination of midazolam plus propofol and propofol alone.

STUDY OBJECTIVE: To compare the hemodynamics, efficacy, safety, and postoperative recovery of patients following the use of either midazolam plus propofol or placebo plus propofol for induction and maintenance of general anesthesia for outpatient surgical procedures of less than two hours' duration. DESIGN: Prospective, parallel, randomized, double-blind, placebo-controlled, multicenter study. SETTING: Ten outpatient surgery centers. PATIENTS: 203 ASA physical status I, II, and III patients undergoing various outpatient surgical procedures. INTERVENTIONS: Patients were randomly assigned to one of the two treatment groups. For induction of anesthesia, Group 1 received midazolam (0.077 +/- 0.0021 mg/kg) via slow intravenous (IV) push plus continuous infusion propofol (provided in a concentration of 5 mg/ml), and Group 2 received placebo plus full-concentration (10 mg/ml) propofol. Thereafter, Group 1 received half-concentration propofol and Group 2 received full-concentration propofol via continuous infusion for maintenance of anesthesia. Investigators administered doses of study medication in a blinded fashion as required to achieve the desired clinical effect. Drugs used to maintain anesthesia were restricted to study drug, short-acting opioids, and nitrous oxide. Succinylcholine chloride or vecuronium were used to facilitate intubation of study patients. MEASUREMENTS AND MAIN RESULTS: There were no statistically significant differences between the midazolam/propofol and placebo/propofol groups with respect to the mean (SE) decrease in mean arterial pressure from pre-dose to time of intubation or from time of intubation to initiation of surgery; the mean (SE) time required from initiation of study medication to completion of intubation [6.7 (0.23) minutes vs. 7.0 (0.26) minutes, respectively]; or the mean (SE) amount of propofol required to induce and maintain anesthesia [6.03 (0.329) mg/kg vs. 9.71 (0.489) mg/kg, respectively]. There was no significant difference between the two treatment groups in the time to recovery following the completion of surgery (as assessed by Aldrete Post Anesthesia Recovery Score). Most patients (approximately 79%) in both groups rated the quality of the anesthetic regimen as excellent; however, as assessed by patient questionnaires, fewer patients in the midazolam/ propofol group were able to recall the events surrounding their surgical procedure as compared with patients in the placebo/ propofol group (89.2% vs. 77.9%; p = 0.022). There were no differences between the two groups with respect to the frequency or severity of adverse events. CONCLUSIONS: Concomitantly administered midazolam and reduction-concentration propofol did not exacerbate the well-described hypotensive effects of full-strength propofol during induction of anesthesia. The time to intubation was equivalent with the combination of midazolam/propofol as compared with propofol alone. Recovery from the two regimens was not significantly different. However, reduced recall of perioperative events was observed more often in the midazolam/propofol regimen compared with propofol alone.

Postoperative analgesia after peripheral nerve block for podiatric surgery: clinical efficacy and chemical stability of lidocaine alone versus lidocaine plus clonidine.

Postoperative analgesia may be prolonged by the addition of clonidine to local anesthetic solutions used for regional anesthesia. The purpose of this study was to test this hypothesis in a clinical trial of patients undergoing podiatric surgery. The study design was prospective, double-blinded, and randomized. Ninety ASA physical status I or II patients scheduled for bunionectomy or hammer toe repair were randomized to receive ankle or metatarsal blocks with plain 1.73% lidocaine (Group L), 1.73% lidocaine with 10 micrograms/mL of clonidine added (Group C10), or 1.73% lidocaine with 20 micrograms/mL clonidine (Group C20). Time from the performance of the block to 1) loss of sensation to pinprick, 2) return of sensation to pinprick, 3) onset of postsurgical pain, and 4) time of first oral pain medication intake were recorded. Beginning at 1 h after the completion of the block, visual analog scale (VAS) and verbal pain scores were recorded every 30 min. Additional postoperative oral pain medication required in the first 9 h after the block was also recorded. Analysis of variance (ANOVA) was used to analyze intergroup differences in the VAS and verbal pain scores, the time to first reported pain, the time to first oral pain medication, and the total amount of oral pain medications required. Repeated-measures ANOVA was used to analyze the VAS and verbal pain scores overall and integrated assessment of pain scores and rescue medication was per-formed. Adverse events were also recorded for each group. There were no differences among the three groups with regard to overall VAS pain scores although Group C10 had significantly better verbal pain scores after the first 3 h (P < 0.05). There was also no difference in time to loss or return of pinprick sensation. Group C10 had a longer time to first reported pain (P < 0.01), a longer time to first oral pain medication (P < 0.01), a lower average total dose of oral pain medication required (P < 0.05), and a lower integrated assessment of pain and medication (P < 0.01) than Group L. More patients in Group C10 reported no pain postoperatively (P < 0.01) and no pain medication taken (P < 0.01) than Group L. Group C20 results suggested no statistically significant improvement over plain lidocaine. One patient in Group C20 experienced significant hypotension postoperatively. pH determinations and chemical analysis by capillary electrophoresis showed no significant change in composition of the solutions when clonidine was mixed with lidocaine and stored at 4 degrees C for 1 wk. Compared to 1.73% lidocaine, combining clonidine (10 micrograms/mL) with lidocaine for local anesthetic block for foot surgery significantly increases the duration and quality of postoperative analgesia.

Comparison of placement of the laryngeal mask airway with endotracheal tube by paramedics and respiratory therapists.

STUDY OBJECTIVE: To determine the learning curve of nonphysician emergency personnel on placement of the laryngeal mask airway as compared to performance of endotracheal intubation. DESIGN: Prospective, comparative, randomized, patient-blinded trial. SETTING: Regional hospital operating room. PARTICIPANTS: Seven experienced paramedics and 12 respiratory therapists trained in endotracheal intubation. INTERVENTIONS: Patients used as subjects were anesthetized and paralyzed. Each participant then performed placement of both the laryngeal mask airway and endotracheal tube on the same patient in random sequence. Both techniques were observed for speed, difficulty, and effectiveness. MEASUREMENTS AND MAIN RESULTS: The techniques were timed from the point at which the participant touched the patient to the time they were able to effectively ventilate the patient. Participants also were asked to rate the difficulty of each technique on a 100-mm visual analog score. Failure (three attempts without successful ventilation) rates also were monitored. The mean time to ventilate successfully with the laryngeal mask airway was significantly less than that with the endotracheal tube (38.9 +/- 1.9 seconds versus 206.1 +/- 31.9 seconds, P < .0001). The average number of attempts was 1.0 +/- 0.0 for the laryngeal mask airway and 2.22 +/- 0.21 for the endotracheal tube (P < .01). No one failed to place the laryngeal mask airway; and ten of 19 (52.6%, P < .01) failed to perform endotracheal intubation. The endotracheal tube had a significantly higher rating of difficulty than did the laryngeal mask airway (67.3 versus 8.64, P < .0001).

Transdermal scopolamine for the reduction of postoperative nausea in outpatient ear surgery: a double-blind, randomized study.

We evaluated the effect of transdermal scopolamine on the incidence of postoperative nausea and vertigo after outpatient ear surgery (exploratory tympanotomy, mastoidectomy, or endolymphatic sac and oval and round window surgery) in a double-blind, placebo-controlled study. A transdermal patch containing either scopolamine (n = 19) or placebo (n = 20) was placed behind the nonsurgical ear 2 h before surgery. Anesthesia was induced with thiopental (4-6 mg/kg intravenously [i.v.]), sufentanil (0.5 microgram/kg i.v.), and vecuronium (0.1 mg/kg i.v.) and maintained with isoflurane (0.2%-2%) and nitrous oxide (70%) in oxygen. Patients were observed postoperatively in the recovery room and after discharge for 72 h. There was no significant difference between groups with respect to time in recovery room, time to discharge, incidence of in-house nausea, vomiting, amount of antiemetics required, or postoperative visual analog scale (VAS) scores while in the hospital. After discharge, there were lower VAS nausea scores (by repeat measures analysis, P < 0.05) and a lower reported incidence of nausea (31% vs 62%; P < 0.05) and vertigo (6.2% vs 25%; P < 0.05) in the active patch group versus the placebo group. There was a higher incidence of dry mouth in the active patch group (44% vs 25%). Seven patients did not complete the study due to failure to keep the patch in place or failure to return the diary from home; and one patient from the placebo patch group was admitted for uncontrolled nausea and vomiting. The authors concluded that transdermal scopolamine is effective in reducing, but not eliminating, postoperative nausea and vertigo after discharge in outpatient ear surgery.

Autonomic reflex dysfunction in patients presenting for elective surgery is associated with hypotension after anesthesia induction.

BACKGROUND: Autonomic reflex dysfunction in patients with diabetes is associated with an increased incidence of hypotension after induction of anesthesia. Whether this finding can be extrapolated to patients with autonomic dysfunction from other causes (e.g., advanced age, hypertension, altered ventricular function) has not been established. METHODS: The authors investigated whether autonomic reflex dysfunction in a more generalized patient group (26 consecutively consenting day-surgery patients older than 39 yr) was similarly associated with the occurrence of hypotension after induction. Preoperative tests of autonomic function included: Valsalva maneuver, change in heart rate with forced breathing, change in heart rate and blood pressure with standing, and spectral analysis of heart rate variability. Anesthesia was induced with 3-5 mg/kg thiopental, 2 micrograms/kg fentanyl, and 60% N2O; 0.1 mg/kg vecuronium was used for paralysis; 0-1.5% isoflurane was added for maintenance of anesthesia after intubation. Noninvasive measurements of mean blood pressure were obtained every minute for 10 min after induction and then every 3 min until skin incision. RESULTS: Twelve patients developed hypotension (mean blood pressure < 70 mmHg), and 14 patients did not. Measurements of autonomic reflex function were significantly more abnormal in the patients who developed hypotension (P < 0.006 for Valsalva measurements, heart rate variability parameters, and change in heart rate with forced breathing). Using critical test values for autonomic tests, the incidence of hypotension was 67-83% in patients with autonomic nervous system dysfunction versus 9-17% in other patients. CONCLUSIONS: The results document that: (1) some degree of autonomic reflex dysfunction is not uncommon in patients older than 39 yr presenting for elective surgery, and (2) such dysfunction is associated with an increased incidence of hypotension when using the described induction technique.

Influence of ketorolac tromethamine on clot elastic strength in humans as assessed by thromboelastography.

STUDY OBJECTIVE: To evaluate the effect of ketorolac tromethamine on coagulation using thromboelastography (TEG). DESIGN: TEGs were performed in each patient before and after ketorolac administration. Each patient's predrug results were used as control measurements for comparison with the postdrug results. SETTING: Medical center surgical unit. PATIENTS: Twenty ASA physical status I and II patients undergoing minor elective surgery; 12 healthy volunteers. INTERVENTIONS: TEGs were performed in all subjects before and 60 minutes after the intramuscular (IM) administration of ketorolac tromethamine 60 mg. Ten surgical patients were studied in the intraoperative period, and 10 surgical patients were studied in the postoperative period. The 12 healthy volunteers did not undergo a surgical procedure. MEASUREMENTS AND MAIN RESULTS: Specific parameters assessed from the TEGs were reaction time (R time), coagulation time (RK time), clot formation rate (angle of deflection), and maximum clot strength (maximum amplitude of deflection). Ketorolac administration did not cause statistically significant changes in these parameters in any of the three groups studied. CONCLUSIONS: IM administration of ketorolac tromethamine 60 mg did not significantly alter the speed of formation or viscoelastic strength of clots as measured by TEG. These results provide additional support for prior clinical studies confirming the safety of ketorolac administration in the perioperative period.