Douglas J. Reinhart

Autonomic Reflex Dysfunction in Patients Presenting for Elective Surgery Is Associated with Hypotension after Anesthesia Induction

BackgroundAutonomic 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. MethodsThe 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. Preoperatlve 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 μg/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. ResultsTwelve 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. ConclusionsThe 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.

Minimising the Adverse Effects of Ketorolac

Gastrointestinal bleeding and perforation, platelet inhibition with altered haemostasis, and renal impairment are among the list of adverse effects associated with the administration of ketorolac. The incidence of serious adverse events has declined since dosage guidelines were revised. Most of the published literature suggests that the overall risk of gastrointestinal or operative site bleeding related to ketorolac therapy is only slightly higher than with opioids. The risk for adverse events, however, increases with high doses, with prolonged therapy (>5 days) or in vulnerable patients (e.g. the elderly). Acute renal failure has been reported after ketorolac treatment but is usually reversible after discontinuation of the drug. As with other nonsteroidal anti-inflammatory drugs (NSAIDs), ketorolac may trigger allergic or hypersensitivity reactions.Careful patient selection is essential if use of ketorolac is considered. Contraindications to ketorolac use include a history of, or current risk of, gastrointestinal bleeding, risk of renal failure, compromised haemostasis, hypersensitivity to aspirin (acetylsalicylic acid) or other NSAIDs, labour, delivery and nursing. Ketorolac should be prescribed at the lowest dosage necessary to control pain; the duration of therapy should also be limited to as few days as possible. Practitioners should be familiar with, and follow, label warnings and dosage guidelines.

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 micro gram/mL of clonidine added (Group C10), or 1.73% lidocaine with 20 micro gram/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 micro gram/mL) with lidocaine for local anesthetic block for foot surgery significantly increases the duration and quality of postoperative analgesia. (Anesth Analg 1996;83:760-5)

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.

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°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.

Postoperative pain control with a new transdermal fentanyl delivery system. A multicenter trial.

Background A new transdermal delivery system for fentanyl is available in two strengths: 70-80 and 90-100 micro gram *symbol* kg sup -1 *symbol* h sup -1 (40- and 60-cm2 patches, respectively). Their short onset and 24-h drug delivery make them attractive for postoperative pain control.

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 patients 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.

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

PurposeTo assess the safety and efficacy of transoermal fentanyl plus im ketorolac vs im ketorolac alone in the treatment of postoperative pain.MethodsNinety-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 mgim. 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.ResultsGroup 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 pruntus 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.ConclusionThe transdermal fentanyl delivery system plus ketorolacim was more effective in controlling postoperative pain than ketorolacim alone. The two treatment modalities were comparable in safety with no difference in serious adverse events.RésuméObjectifÉvaluer en rapport avec le traitement de la douleur postopératoire la sécurité et l’efficacité du fentanyl transdermique associé au kétorolac avec celles du kétorolac seul.MéthodesQuatre-vingt-douze patients programmés pour une chirurgie comportant des douleurs postopératoires modérées à graves étaient répartis aléatoirement entre deux groupes. Le groupe A (n = 46) recevait un timbre autocollant au fentanyl et le groupe P (n=46) un timbre placebo. Les timbres demeuraient en place pendant 24 h. Chaque patient recevait 60 mg de kétorolacim pendant l’intervention. Les patients étaient gardés sous surveillance pendant 36 h après l’intervention et la dose de kétorolac utilisée, les scores de douleur, les signes vitaux, les concentrations de fentanyl et les incidents indésirables étaient notés. Du kétorolac était administréim sur demande.RésultatsLes patients du groupe A présentaient les scores de douleur les plus bas à 8, 12. 16 et 24 h après l’application du timbre (P< 0.05). Les patients du groupe A avaient la fréquence cardiaque et respiratoire la plus lente et le moins de décrochage par insatisfaction (4,3%vs 21,7%

Fatal outcome during endoscopic sinus surgery: anesthetic manifestations.

, P< 0,05). Les patients du groupe A ont aussi utilisé moins de kétorolac que ceux du groupe P (P< 0.05). Lincidence de prurit était plus élevée chez les patients du groupe A (19% vs 2%. (P< 0.05), alors que l’incidence des nausées et des vomissements était la même dans les deux groupes. Le fentanyl transdermique n’était suffisant comme analgésique unique que dans seulement 23,8% des patients du groupe A; 93.7% des autres patients du groupe A qui avaient reçu une combinaison de fentanyl transdermique et de kétorolac étaient suffisamment soulagés.ConclusionsL’administration transdermique de fentanyl associé au kétorolacim a été plus efficace pour soulager la douleur que le kétorolacim seul. Sous l’aspect de la sécunté et des incidents indésirables, les deux méthodes étaient comparables.

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

ndoscopic sinus surgery is a n increasingly popular technique for the treatment of chronic siE nusitis (1). Although serious complications are rare, fatalities have been reported in the otorhinolaryngologic literature (2-5). We report a fatal complication of endoscopic sinus surgery that initially presented as severe hemodynamic instability with electrocardiogram evidence of ischemia. This severe complication was marked by excessive bleeding, failure to emerge from anesthesia, and focal neurologic deficits.