Comparison of 27-gauge (0.41-mm) Whitacre and Quincke spinal needles with respect to post-dural puncture headache and non-dural puncture headache.

BACKGROUND: The incidence of headache after spinal anaesthesia has varied greatly between studies. We compared the incidence of postoperative headache in general and postdural puncture headache (PDPH) when using 27-gauge (G) (outer diameter 0.41 mm) Quincke and Whitacre spinal needles in ambulatory surgery performed under spinal anaesthesia. METHODS: In a prospective, randomized study, 676 ASA physical status I-II day-case outpatients were given a spinal anaesthetic through either a 27-G (0.41 mm) Quincke or a 27-G (0.41 mm) Whitacre spinal needle. The incidence of any type of postoperative headache was assessed and the type of headache defined using a standardized questionnaire including PDPH criteria. The severity of the headache was defined using a 100-mm visual analogue scale. RESULTS: For the final analysis, 529 patients were available (259 patients in the Quincke group and 270 patients in the Whitacre group). The overall incidence of postoperative headache was 20.0%, but the incidence of true PDPH was very low (1.51%). The incidence of PDPH in the Quincke group was 2.70%, while in the Whitacre group it was only 0.37% (P < 0.05). The overall incidence of non-dural puncture headache was 18.5% and did not differ between the study groups. CONCLUSIONS: True PDPH seldom occurs when a 27-G (0.41 mm) spinal needle is used, although postoperatively a non-specific headache is common. Using the 27-G (0.41 mm) Whitacre spinal needle further reduced the incidence of PDPH. Thus, we recommend routine use of the 27-G (0.41 mm) Whitacre spinal needle when performing spinal anaesthesia.

Double-blind comparison of the variability in spontaneous recovery of cisatracurium- and vecuronium-induced neuromuscular block in adult and elderly patients.

BACKGROUND: This study was designed to compare variability in the offset of two neuromuscular blocking agents with different elimination pathways. METHODS: The spontaneous recovery profiles of cisatracurium and vecuronium were compared in adult (18-64 years) and elderly (> or =65 years) patients receiving N2O/O2/fentanyl/propofol anaesthesia. Patients were randomised to receive an initial bolus dose and maintenance doses of 3xED95, respectively, 0.6xED95 for cisatracurium (0.15 and 0.03 mg.kg-1) or 2xED95, respectively, and 0.4xED95 for vecuronium (0.1 and 0.02 mg.kg(-1)), as recommended in their prescribing information. Administration of the study drugs was double-blinded, and neuromuscular transmission was monitored using mechanomyography of the evoked response of the adductor pollicis, following ulnar nerve stimulation. RESULTS: The clinically effective duration (minutes) of the initial bolus dose, defined as the mean time to 25% T1 recovery (+/-SD), for the adult and elderly patients was 53.5+/-9.8 and 57.3+/-11.5 for cisatracurium, respectively, and 34.1+/-9.0 and 47.5+/-14.4 for vecuronium, respectively. The duration of spontaneous sufficient recovery (SSR), defined as the mean (+/-SD) time interval in minutes from 25% T1 recovery to a T4:T1 ratio > or =0.8 after the last bolus dose, for the adult, respectively, elderly patients was 28.3+/-8.0 and 31.7+/-10.0 for cisatracurium and 38.5+/-13.2 and 60.3+/-26.1 for vecuronium. CONCLUSION: Whereas both the clinically effective duration and the duration of SSR are comparable between the adult and the elderly patients receiving cisatracurium, they differ substantially between these two age groups for vecuronium. Furthermore, the variability in offset is significantly lower in patients receiving cisatracurium, especially in the elderly, which may be of particular clinical interest.

Peroral tramadol premedication increases postoperative nausea and delays home-readiness in day-case knee arthroscopy patients.

BACKGROUND AND AIMS: To evaluate the effect of preoperative oral tramadol on postoperative pain and its effect on the patient's home-readiness after diagnostic day-case knee arthroscopy performed under spinal anaesthesia. MATERIAL AND METHODS: We studied 156 outpatients in a prospective, randomized, double-blind fashion to examine the postoperative analgesic effect of preoperative oral slow-release tramadol. Postoperative pain was measured using a 100-mm visual analogue scale (VAS). Postoperative nausea and vomiting (PONV) and the patients home-readiness were assessed. RESULTS: There were no statistically significant differences in the postoperative VAS scores between the tramadol and placebo groups, nor was there any significant difference in the need for postoperative pain medication. Patients in the tramadol group had higher incidence of PONV and they were discharged from hospital later than those given placebo although the tramadol patients required less intravenous midazolam for sedation. CONCLUSIONS: Preoperatively given slow-release tramadol is ineffective for reduction of postoperative pain after day-case arthroscopy of the knee. Additionally, preoperative tramadol is associated with higher incidence of PONV and it seems to cause delay in the patient's home-readiness.

Preoperative diclofenac is a useful adjunct to spinal anesthesia for day-case varicose vein repair.

PURPOSE: To examine if preoperative diclofenac 50 mg or diazepam 10 mg po are useful adjuncts to spinal anesthesia for day-case varicose vein repair. METHODS: Two hundred ASA physical status I-II outpatients, age 18-60 yr, were randomized to receive either diclofenac 50 mg po or diazepam 10 mg po one hour before operation in a double-blind fashion (100 patients in both groups). If the patient was distressed or feared the spinal puncture and requested sedation, a bolus dose of alfentanil 0.5 mg was given i.v. as a rescue medication. On request, patients received diclofenac 50 mg po and, when needed, oxycodone 0.1 mg x kg(-1) im for postoperative pain relief. They were discharged with a supply of diclofenac 50 mg tablets and were asked to record postoperative pain using a visual analogue scale (VAS) and quantity of tablets taken. RESULTS: The VAS scores (+/- SD) eight hours after surgery, the next morning, and in the morning and at the end of the first and second postoperative days were 23 +/- 21, 12 +/- 17, 11 +/- 15, 8 +/- 15 and 8 +/- 15 in the diclofenac group, and 24 +/- 23, 12 +/- 20, 10 +/- 17, 8 +/- 16 and 7 +/- 14 in the diazepam group, respectively (NS). In the diclofenac and diazepam groups, 31% and 67% of the patients required postoperative diclofenac during the first eight postoperative hours (P <0.05). Diazepam premedication did not alter the number of patients who required alfentanil before spinal puncture. CONCLUSION: Diclofenac premedication reduced the analgesic requirements during the first eight hours after varicose vein repair.

Intra-articular ropivacaine injection does not alleviate pain after day-case knee arthroscopy performed under spinal anaesthesia.

BACKGROUND AND AIMS: To evaluate the effect of intra-articular ropivacaine injection on postoperative knee pain after day case arthroscopy. MATERIAL AND METHODS: We studied one hundred outpatients in a prospective, randomized, double-blind fashion to examine the postoperative analgesic effect of intra-articular ropivacaine or saline injected into the knee joint after day-case knee arthroscopy performed under spinal anaesthesia. Patients were interviewed postoperatively with a standardized questionnaire. The postoperative pain was measured using a 100-mm visual analogue scale (VAS). RESULTS: There were no statistically significant differences in the VAS scores of knee pain eight hours or more after the operation between the intra-articular ropivacaine and saline groups, and there was no significant difference in the need for postoperative pain killer. CONCLUSIONS: This study failed to demonstrate a decrease in postoperative VAS scores at eight hours and later postoperatively when 20 ml of ropivacaine 0.5% were injected intra-articularly after day-case knee arthroscopy performed under spinal anaesthesia. Furthermore, there was no significant difference in the need for postoperative pain medication between the study groups.

Diclofenac premedication but not intra-articular ropivacaine alleviates pain following day-case knee arthroscopy.

PURPOSE: To compare the postoperative analgesic effects of 50 mg diclofenac p.o. before surgery and intra-articular ropivacaine injected after diagnostic day-case knee arthroscopy performed under spinal anesthesia. METHODS: In a randomized, double-blind investigation, 200 ASA physical status 1-2 outpatients, age 18-60 yr, received either 50 mg diclofenac p.o. or placebo one hour before operation (100 patients per group), and intraarticular injections of either 20 ml of ropivacaine 0.5% or 20 ml of saline 0.9% (50 patients in each premedication groups). Patients received 50 mg diclofenac p.o. prn and, if needed, 0.1 mg x kg(-1) oxycodone im for postoperative pain relief. Patients were discharged home with a supply of 50 mg diclofenac tablets and were given a sheet of paper with knee pain VAS scales and a questionnaire of analgesics taken. Patients rated their VAS scores eight hours after surgery and in the moming and at the end of the first and the second postoperative days, respectively. RESULTS: The only statistically significant difference was found when the diclofenac groups were combined and compared with the combined placebo premedication groups. The VAS scores of knee pain at eight hours after the operation were 19+/-22 in the two diclofenac premedication groups and 32+/-28 in the two placebo groups (P = 0.001). CONCLUSIONS: Diclofenac premedication p.o. reduced the VAS scores at eight hours postoperatively while intra-articular ropivacaine did not.

Potency and hourly maintenance requirement of combinations of mivacurium and pancuronium in adults.

PURPOSE: To evaluate the dose-response and maintenance requirements of a combination of mivacurium and pancuronium (cMP) in clinical practice. METHODS: In a randomised, open clinical study, 70 patients, 17-50 yr of age, were anaesthetised with propofol, alfentanil and nitrous oxide in oxygen. Thirty patients received mivacurium and 20 patients received pancuronium to establish dose-response curves for these agents. Hourly maintenance requirements of mivacurium and pancuronium to maintain 90-95% neuromuscular blockade (NMB) were determined. Thereafter, 20 additional patients received cMP in incremental doses to establish a cumulative dose-response curve for cMP followed by maintenance doses of cMP. NMB was recorded by adductor pollicis electromyography. RESULTS: The ED95 values for mivacurium and pancuronium were 100 and 66 micrograms.kg-1, respectively; and for the cMP 2:1 (in mg:mg basis), 32 micrograms.kg-1 mivacurium together with 16 micrograms.kg-1 pancuronium. This cMP was 1.8 times more potent than one parent agent (P < 0.0001). When cMP 2:1 was used, 60% of normal maintenance requirement of pancuronium reduced the requirement of mivacurium by > 90%. If cMP 20:1 was used, then 20% of normal maintenance requirement of pancuronium reduced the requirement of mivacurium by > 70%. Neostigmine 35 micrograms.kg-1 given at T1 10% recovery following cMP reversed the NMB to a TOF ratio of 0.70 in 9.5 +/- 3.9 min. CONCLUSION: These results reflect considerable synergism between mivacurium and pancuronium. The cMP is near intermediate-acting and the NMB is easily reversed with neostigmine. By using cMP, it may be possible to save some pharmacological costs during maintenance of anaesthesia.

Pipecuronium revisited: dose-response and maintenance requirement in infants, children, and adults.

STUDY OBJECTIVE: To compare dose-response relationship and maintenance requirement of pipecuronium in anesthetized infants, children, and adults. DESIGN: Prospective, consecutive sample trial. SETTING: Operating room at a university hospital. PATIENTS: 15 infants (1-11 months), 15 children (3-10 years), and 15 adults (35-50 years) of ASA physical status I and II. INTERVENTIONS: Anesthesia was induced and maintained with N2O:O2 2:1 and 1 minimum alveolar concentration end-tidal halothane. The neuromuscular function was recorded by adductor pollicis electromyogram evoked by a train-of-four ulnar nerve stimulation at 20 second intervals. An individual cumulative log-probit dose-response curve was established and maintenance requirement of pipecuronium determined. Between-group comparisons were made by analysis of variance and Scheffe F-test. MEASUREMENTS AND MAIN RESULTS: Dose-response curves were parallel with a dose-requirement of pipecuronium similar in infants and adults (ED95 of 40-42 micrograms/kg) and greater in children (ED95 of 52 micrograms/kg). After 30 minutes of surgical neuromuscular block, pipecuronium was required in each age group at a rate of 0.6 to 0.7 individual ED95 doses per hour to maintain an 85% to 95% neuromuscular block. CONCLUSIONS: Bolus dose requirement of pipecuronium is greatest in children. Maintenance requirement is related to potency in each age group studied.

Mivacurium when preceded by pancuronium becomes a long-acting muscle relaxant.

BACKGROUND: To ensure rapid recovery of neuromuscular block, it might be useful to administer a short-acting relaxant after a long-acting one. Therefore, the interaction between pancuronium and mivacurium was investigated when mivacurium was administered during the recovery from pancuronium block. METHODS: After written informed consent, 41 adult patients were studied during propofol/alfentanil/nitrous oxide/oxygen anesthesia. Neuromuscular function was monitored using an electromyographic (EMG) method. AFter a stable EMG calibration response, cumulative doses of pancuronium were given to establish a 95% neuromuscular block. In the control group, and ED95 dose of 100 microg/kg mivacurium was administered instead of pancuronium. When the EMG response after pancuronium or mivacurium had recovered to 25% of the baseline, a single randomized intravenous bolus dose of 10 or 70 microg/kg mivacurium was given. Thereafter, spontaneous recovery of the neuromuscular function was recorded. RESULTS: The time from pancuronium until T1 25% EMG recovery was 38 +/- 12 min (mean +/- SD). The respective times after 10 or 70 microg/kg mivacurium were 28 +/- 8 and 54 +/- 7 min in the pancuronium group or 3 +/- 1 (n=3) and 10 +/- 4 min in the mivacurium group (P=0.0001). Times to 95% EMG recovery after 10 or 70 microgm/kg mivacurium were 77 +/- 14 and 97 +/- 16 min in the pancuronium group and 11 +/- 3 and 20 +/- 7 min in the mivacurium group, respectively (P<0.0001). Recovery indexes after 10 or 70 microg/kg mivacurium group, respectively (P<0.0001). Recovery indexes after 10 or 70 microg/kg mivacurium wre 26 +/- 4 and 22 +/- 6 min in the pancuronium group or 7 +/- 3 (n=3) and 5+/- 2 min in the mivacurium group, respectively (P<0.0001). Times from the administration of 10 or 70 microg/kg mivacurium until train-of-four ration 0.7 were 94 +/- 16 and 111 +/- 14 min in the pancuronium group and 12 +/- 4 and 22 +/- 8 min in the mivacurium group, respectively (P<0.0001). CONCLUSIONS: After pancuronium, mivacurium is not a short acting neuromusclar blocking agent.

Rocuronium in infants, children and adults during balanced anaesthesia.

We studied 20 infants, 20 children and 20 adults during balanced anaesthesia to compare the neuromuscular blocking effects of rocuronium in these age groups. Neuromuscular function was recorded by adductor pollicis emg and a cumulative log-probit dose-response curve of rocuronium was established. Thereafter, full spontaneous recovery of the neuromuscular function was recorded. Onset time of the first dose of rocuronium was shorter in children than in infants or adults. The potency of rocuronium was greatest in infants and least in children; the ED50 doses (mean +/- SD) being 149 +/- 36 micrograms.kg-1 in infants, 205 +/- 52 micrograms.kg-1 in children and 169 +/- 47 micrograms.kg-1 in adults (P < 0.05 between infants and children) and the ED95 doses being 251 +/- 73 micrograms.kg-1, 409 +/- 71 micrograms.kg-1 and 350 +/- 77 micrograms.kg-1, respectively (P < 0.05 between all groups). The emg recovery following an average 94.5 +/- 4.8% neuromuscular blockade established by rocuronium was roughly similar in all study groups. Thus, one ED95 dose of rocuronium, unlike vecuronium, acts as an intermediate-acting agent in all age groups.

The duration of action of mivacurium is prolonged if preceded by atracurium or vecuronium.

We studied 45 patients (ASA I-II) during propofol-alfentanil-N2O-O2 anaesthesia to determine if recovery from neuromuscular block induced by mivacurium is influenced differently by prior injection of atracurium or vecuronium. Neuromuscular function was monitored by adductor pollicis EMG. Patients were randomized to receive two doses of either mivacurium (150 and 70 micrograms kg-1), atracurium (350 and 75 micrograms kg-1) or vecuronium (70 and 15 micrograms kg-1) followed by a final dose of mivacurium 70 micrograms kg-1. The second and third doses of the muscle relaxants were administered at 25-30% recovery of the E1 (first EMG response in the train-of-four series). Following the final dose of mivacurium, the EMG response recovered to 25 and 95% in 10.4 +/- 3.9 and 19.7 +/- 5.7 min (mean +/- SD), respectively, if mivacurium was the only muscle relaxant. Respective times were 100% longer if mivacurium had been preceded by atracurium (23.8 +/- 3.3 and 39.8 +/- 6.9) or vecuronium (22.6 +/- 3.5 and 44.1 +/- 7.9 min) (P = 0.0001). The 25-75% recovery times in the three groups were 4.9 +/- 1.0, 8.7 +/- 2.4 and 10.5 +/ 2.5 min, respectively (P = 0.0001). Our results indicate that there is no benefit in giving mivacurium at the end of surgery after peroperative use of atracurium or vecuronium.

Dose-response and time-course of effect of rocuronium bromide in paediatric patients.

We determined dose-response curves and spontaneous recovery of neuromuscular function following a single ED95 dose of rocuronium in 10 infants (1-11 months old), 20 children (2-12 years old) and 20 adults (20-40 years old) during nitrous oxide-oxygen-thiopentone-alfentanil anaesthesia. Neuromuscular block was recorded as adductor pollicis EMG following a supramaximal train-of-four ulnar nerve stimuli at 10 s intervals. ED95 values were significantly less for infants than for children or adults (255 +/- 62, 402 +/- 68 and 350 +/- 78 micrograms kg-1, respectively, P = 0.0001). Time-course of recovery from an average 94% neuromuscular block was similar in all age groups with a 25-75% recovery time of 6.5 +/- 1.8, 5.7 +/- 1.8 and 6.7 +/- 1.6 min in infants, children and adults, respectively. Thus, rocuronium is an intermediate-acting muscle relaxant in all age groups.

Ranitidine suspension or famotidine resoriblette and gastric fluid volume and pH.

We studied the effect of two new formulations of H2-receptor antagonists on gastric fluid pH and volume. Forty-five healthy, elective adult in-patients in three study groups, 15 in each, were premedicated using oral diazepam 10 mg with 100 ml of a dose of water soluble suspension of ranitidine 300 mg with sodium citrate/bicarbonate, or a resoriblette of famotidine 40 mg, or placebo. Gastric fluid samples were obtained by blind aspiration after anaesthesia induction, 50-70 min from premedication, and again 90 min from premedication. After a mean period of 60 min from ingestion the patients medicated with H2-antagonists had higher gastric juice pH than those in the control group (1.5 (1.1-6.3), median (range)) (P < 0.0001) for ranitidine (6.8 (4.1-7.8)), P < 0.01 for famotidine (3.9 (1.5-7.6)); P < 0.05 ranitidine vs famotidine). Recovered volumes were similar for the groups (median 3-4 ml, range 0-50 ml). None of the H2 patients had pH < 3.5 and volume > or = 0.3 ml.kg-1 (P < 0.05 vs placebo). In second aspirations, taken 90 min from premedication, the group differences from control in pH persisted. Famotidine patients had the lowest volumes (P < 0.05 vs controls); yet one famotidine patient had a pH < 2.5 and volume > or = 0.3 ml.kg-1. It is concluded that, at the moment of oral anxiolytic premedication, ranitidine-buffer suspension effectively reduced gastric juice acidity, whereas famotidine resoriblette failed to increase reliably gastric pH in 50-90 min.

Synergism between mivacurium and pancuronium in adults.

Mivacurium could be a useful agent as a final dose of a muscle relaxant following pancuronium if only additivity exists between these agents. We examined the interaction between mivacurium and pancuronium in 70 patients (ASA I-II) during propofol-alfentanil-N2O-O2 anaesthesia. Neuromuscular function was monitored by adductor pollicis EMG. Firstly we established dose-response curves for mivacurium and pancuronium. Thereafter, 20 patients received a combination of 0.5 times the ED50 doses of mivacurium and pancuronium (cMP) determined in the first part of this study. Patients were randomized to receive the cMP to the same IV-line (n = 10) or to two separate IV-lines in opposite hands (n = 10). ED50 values for mivacurium and pancuronium were 57.7 and 37.1 micrograms kg-1, respectively. Maximal neuromuscular block following the cMP was 91.8 +/- 5.0% (mean +/- SD). This was highly significantly different from the estimated 50% NMB if only additivity exists between mivacurium and pancuronium (P = 0.0001). After the cMP, the 25-75% recovery time was 9.4 +/- 1.3 min and the time to train-of-four ratio of 0.70 was 35.8 +/- 5.4 min. There was no statistical difference in any recorded neuromuscular parameter between the two subgroups receiving mivacurium and pancuronium to the same or to opposite hands (P > 0.40). We conclude that a significant synergism exists between mivacurium and pancuronium which may indicate that mivacurium does not produce a short-acting NMB if given after pancuronium. We do not recommend using mivacurium together with pancuronium.

Interaction between mivacurium and succinylcholine.

We investigated the interaction between mivacurium and succinylcholine when mivacurium was administered during the early recovery from succinylcholine block. We studied 40 adult patients during propofol-alfentanil-N2O-O2 anesthesia. Neuromuscular function was monitored using an electromyographic method (Relaxograph, Datex, Helsinki, Finland). Patients randomly received either 1.0 mg/kg of succinyl-choline followed by 0.15 mg/kg of mivacurium when the first twitch (T1) during succinylcholine block recovered to 5%, or 0.15 mg/kg of mivacurium without succinylcholine. Serum cholinesterase activity was lower than normal range in two patients and higher than normal range in four patients, but the dibucaine number value was normal in every patient. The mean onset time (3.8 +/- 0.9 min) (mean +/- SD) or maximal neuromuscular block (96.6% +/- 7.2%) of mivacurium did not differ between the groups. The T1 recovery times of mivacurium were slightly shorter (P < 0.05) after succinylcholine administration than without it. During recovery of mivacurium block, the fade was significantly greater, i.e., the train-of-four (TOF) ratio was lower, after succinylcholine administration than without it. Recovery index (T1 25%-75%, mean 4.7 +/- 1.3 min) and the time from the administration of mivacurium to the recovery of TOF ratio 0.7 (mean 20.4 +/- 5.1 min) were not different between the groups. In conclusion, in healthy patients succinylcholine has negligible effects on a subsequent mivacurium-induced neuromuscular block.

Potency and maintenance requirement of atracurium and vecuronium given alone or together.

A synergism exists between some competitive muscle relaxants. However, maintenance requirement of a combination of muscle relaxants has been evaluated only in paediatric patients. We studied 45 elective adult surgical patients (ASA I-II) during propofol-alfentanyl-N2O-O2-anaesthesia. The first 30 patients were randomized to receive either atracurium or vecuronium to create individual dose-response curves for these muscle relaxants. ED95-values for atracurium and vecuronium were 260 +/- 9 and 59 +/- 3 micrograms.kg-1, respectively (mean +/- s.e. mean). Requirements of atracurium and vecuronium to maintain an 85-95% neuromuscular blockade were 301 and 83 micrograms kg-1 h-1, respectively. An additional 15 patients received a combination of atracurium and vecuronium (cAV) in an equipotent dose ratio. An ED95 of a cAV was 94 +/- 7 micrograms.kg-1 of atracurium together with 21 +/- 2 micrograms.kg-1 of vecuronium, or 72 +/- 6% of one ED95 dose of a parent agent. Potentiation was significant (P = 0.0001). A maintenance requirement of a cAV was 120 micrograms kg-1 h-1 of atracurium together with 27 micrograms kg-1 h-1 of vecuronium. Thus, a significant potentiation was maintained also during the course of anaesthesia. A cAV had an effect like one intermediate-acting agent. If a cAV is used instead of using atracurium or vecuronium alone, the maximal reduction of drug consumption would be approximately 30%.

Comparison of intramuscular dexmedetomidine and midazolam premedication for elective abdominal hysterectomy.

The purpose of this study was to compare the perioperative effects of the intramuscular (i.m.) alpha 2 agonist, dexmedetomidine (DEX), and midazolam (MID) premedication. The study comprised 192 women (64 per group) scheduled for abdominal hysterectomy. The doses of the study drugs were chosen to obtain equal sedative effects. The three groups were: 1) i.m. DEX (2.5 micrograms/kg) and intravenous (i.v.) placebo (DexPla group), 2) i.m. DEX and i.v. fentanyl (FENT) (1.5 micrograms/kg) (DexFent group), and 3) i.m. MID (0.08 mg/kg) and i.v. FENT (MidFent group). I.m. drugs were administered 45-90 min before induction of anesthesia. Preoperative sedation and anxiolysis after DEX was comparable to that after MID. The maximum arterial blood pressure response to endotracheal intubation was blunted in the DexFent group, while in the two other groups blood pressure increased 30-34 mm Hg after endotracheal intubation. The mean isoflurane concentration during surgery was 0.14% in the DexFent group, 0.24% in the DexPla group, and 0.34% in the MidFent group (P < 0.001). During surgery, bradycardia (heart rate < 40 bpm) was observed in 6.2% of DEX patients, and no MID patients, whereas postoperatively 14.1% of DEX patients and 1.6% of MID patients had bradycardia. Fewer patients suffered from postoperative shivering after DEX (10%) than after MID (52%). We conclude that DEX has many desirable effects, but side effects such as bradycardia may limit its routine use in ASA physical status I-II patients.

Comparison of dexmedetomidine and midazolam sedation and antagonism of dexmedetomidine with atipamezole.

STUDY OBJECTIVE: To evaluate the effects of dexmedetomidine, an alpha-2 agonist, as an intravenous sedative drug and the effects of atipamezole, an alpha-2 antagonist, on recovery. DESIGN: Randomized, double-blind study with three parallel groups. An open dose-finding study preceded it to optimize the atipamezole dose. SETTING: Outpatient operating room at the gynecologic and obstetric university hospital in Helsinki, Finland. PATIENTS: Seventy-two healthy women scheduled for legal termination of pregnancy. INTERVENTIONS: Patients were assigned to one of three groups of 24 patients each to receive either dexmedetomidine 2 micrograms/kg and atipamezole 50 micrograms/kg; dexmetomidine 2 micrograms/kg and saline; or midazolam 0.15 mg/kg and saline. In addition to paracervical block, each patient received two different study drugs: study drug 1 was a sedative agent (either dexmedetomidine or midazolam), administered before the procedure. If the sedation was not deep enough and the patient reacted to the procedure, a low dose of propofol was administered. Study drug 2 was a reversing agent or a placebo, administered following the procedure. MEASUREMENTS AND MAIN RESULTS: The mean time to regain consciousness was shorter in the dexmedetomidine-atipamezole and the dexmedetomidine-saline groups compared with the midazolam group. Postoperative sedation, tested both by subjective and objective assessments, decreased more quickly in the dexmedetomidine-atipamezole group compared with the dexmedetomidine-saline and the midazolam groups. CONCLUSION: Atipamezole is an effective antagonist for reversing psychomotor impairment following dexmedetomidine sedation.

Predictive value of manual ECG-monitored exercise test before abdominal aortic or peripheral vascular surgery.

The value of manual ECG-monitored exercise test was studied in 58 patients (39 men and 19 women) with intermittent claudication scheduled for abdominal or peripheral vascular surgery. There was a high incidence of well-known risk factors (hypercholesterolemia, smoking, and hypertension) in men and women. History of coronary artery disease (CAD) was present in 29.3% of the patients. No correlation was found between patients with single or multiple stenoses in lower extremity arteries (angiography) and CAD. Ischemic response (ECG) to manual exercise testing was positive in 14 patients (24.1%), of whom 2 (14.3%) had major cardiovascular postoperative complications. Both died of acute myocardial infarction within fourteen days. They had slow recovery (thirty to sixty minutes) of the ST segment (0.3-0.6 mV). The authors conclude that manual exercise testing might reveal serious CAD in patients with severe occlusive peripheral arterial disease of the lower extremities. In cases with slow recovery of ischemic response to exercise, coronary bypass or angioplasty could be advantageous before major vascular surgery.