Premixing lidocaine reduces the incidence and severity of pain on injection of propofol

The purpose of this study was to confirm the effect of premixed lidocaine for the reduction of pain during injection of propofol in adult patients. We conducted a prospective, randomized, double-blind trial on 106 patients. In the study group (n = 54), lidocaine 40 mg (2 ml of lidocaine 2%) was added to 180 mg of propofol (18 ml). In the control group (n = 52), 2 ml of normal saline was added to 180 mg of propofol. The pain on injection was rated as none, mild, moderate, or severe. Eleven patients (20.4%) in the study group experienced pain compared with 25 (48.1%) in the control group. Thirteen in the control group complained moderate or severe pain compared with only one in the study group. In conclusion, lidocaine 40 mg premixed with 180 mg propofol significantly reduces the incidence and severity of pain associated with propofol injection.     

Should interstitial thermometry be used for deep hyperthermia?

This study was performed to determine whether premedication with midazolam and fentanyl prevents reliable detection of an i.v. lidocaine test dose. Thirty ASA physical status I or II patients received either 3 mL of saline or 1.5 mg of midazolam (1.5 mL) plus 75 microg of fentanyl (1.5 mL) i.v. in a randomized, double-blind fashion. Five minutes later, lidocaine 1 mg/kg was injected i.v. At 1.5 min before and every minute after lidocaine administration, each subject was questioned regarding the presence of four symptoms of systemic lidocaine toxicity. Any new tinnitus, perioral numbness, metallic taste, or light-headedness within 5 min after lidocaine administration was considered a positive response. All 15 patients in the saline group (100% sensitivity) had a positive response to i.v. lidocaine, but only 9 of 15 patients in the sedation group had a positive response (60% sensitivity; P = 0.017). We conclude that midazolam and fentanyl premedication decreases the reliability of subjective detection of i.v. lidocaine. Implications: Anesthesiologists often rely on subjective symptoms to prevent local anesthetic toxicity while performing regional anesthesia. Sedatives are often administered during the administration of regional anesthesia. This study demonstrates that typical sedation decreases the reliability of detection of local anesthetic toxicity by subjective symptoms.     

Relationship between auditory intensity discrimination in noise and olivocochlear efferent system activity in humans

The intravenous (i.v.) steroid anesthetic, eltanolone, compares favorably to propofol with respect to its induction characteristics. This double-blind investigation was designed to compare the induction and recovery profile of eltanolone (versus propofol) when it was used for both induction and maintenance of ambulatory anesthesia. Eighty-three consenting ASA physical status I-III outpatients undergoing minor gynecologic or urologic procedures lasting 10-40 min were randomly assigned to one of three anesthetic treatment groups. All patients received midazolam, 2 mg i.v., and fentanyl, 50 micrograms i.v., before induction of anesthesia. The control group (Group 1) was induced with propofol, 2.4 mg/kg i.v. (18-60 yr or ASA physical status I or II) or 1.6 mg/kg i.v. (61-80 yr and/or ASA physical status III), followed by intermittent bolus doses of 0.6 mg/kg i.v. in combination with N2O 67% for maintenance of anesthesia. In Group 2, anesthesia was induced with eltanolone, 0.75 mg/kg i.v., (18-60 yr and/or ASA physical status I or II) or 0.5 mg/kg i.v. (61-80 yr and/or ASA physical status III), and maintained with intermittent bolus injections of 0.2 mg/kg i.v. and N2O 67%. Group 3 received eltanolone, 1.0 mg/kg i.v. (18-60 yr and/or ASA physical status I or II), or 0.75 mg/kg i.v. (61-80 yr and/or ASA physical status III), followed by intermittent bolus injections of 0.2 mg/kg i.v. and N2O 67%. In addition to recording the induction and recovery times and side effects, psychomotor testing was performed before and at 30-min intervals after anesthesia. Induction times (57 +/- 23, 67 +/- 26, and 61 +/- 22s, respectively) were similar in all three groups. Although eltanolone produced no pain on injection (versus 52% in the propofol group), 10% of the eltanolone-treated patients (versus none in the propofol group) developed transient cutaneous (rash-like) reactions. The total dose of study medication used during the anesthetic period was 9.2 +/- 3.7 mg.kg-1.h-1 in the propofol group compared with 3.3 +/- 1.4 mg.kg-1.h-1 and 3.3 +/- 1.9 mg.kg-1.h-1 in Groups 2 and 3, respectively. Early recovery times were significantly shorter after propofol anesthesia. However, times to ambulation, micturition, and being judged "fit for discharge," as well as recovery of cognitive function, were similar in all three groups. Although ethanolone seems to be a safe and effective i.v. anesthetic, these data suggest that it is unlikely to replace propofol in the ambulatory setting. Implications: Eltanolone is an investigational steroid anesthetic that causes less pain on injection and less cardiovascular depression than propofol (the most widely used intravenous anesthetic in the outpatient setting). Unfortunately, emergence from anesthesia after ambulatory surgery is slower with eltanolone compared with propofol. Therefore, it is unlikely that eltanolone will replace propofol for outpatient anesthesia.     

Propofol and etomidate-Lipuro for induction of general anesthesia. Hemodynamics, vascular compatibility, subjective findings and postoperative nausea

Etomidate has become an important induction agent in high-risk patients because of its cardiovascular stability. Its unwanted side-effects such as pain on injection and thrombophlebitis could be significantly reduced by a new (medium chain triglyceride and soya bean) emulsion formulation. Propofol is solved in a mixture of long chain triglyceride and soya bean emulsion. In this double-blind, randomized study we compared the haemodynamic effects, the patients' sensations, signs of thrombophlebitis and postoperative nausea and vomiting (PONV) following injection of both drugs. METHODS: Following premedication with 2 mg Lormetazepam p.o. in 50 patients per group, anaesthesia was induced with either 0.51 mg etomidate in lipid emulsion or 3.04 mg propofol per kg bw. No opioid or benzdiazepine was given i.v. before induction. After injection of the tested drug, the cannula was removed. Changes in blood pressure and heart rate were recorded as well as signs of discomfort during and after injection (pain, burning, tension, cold). Venous sequelae were assessed for 5 days after injection to register signs of thrombophlebitis. RESULTS: Demographic data showed no difference between the two groups. After propofol more often a fall in blood pressure was seen. Pain (25 vs 1 pt), burning 19 vs 1), tension 15 vs 3), cold (35 vs 17) after injection was registered significantly more often in the propofol group, whereas myocloni predominated in the etomidate group (13 vs 6) P < 0.05, chi-squared-test). No difference was seen in PONV in either groups. CONCLUSION: Etomidate formulated in a medium chain lipid emulsion causes significant less discomfort for the patients than propofol, which is solved in a long chain formulation. Myocloni, however, occur significantly more frequently after etomidate than after propofol.     

Comparison of perioperative ketoprofen 2.0 mg kg-1 with 0.5 mg kg-1 i.v. in small children during adenoidectomy

We have investigated if ketoprofen 0.5 mg kg-1 i.v. provided as good analgesia with less adverse effects compared with ketoprofen 2.0 mg kg-1 i.v. in 107 children, aged 1-7 yr, after adenoidectomy, in a randomized, double-blind, parallel group study design. A standard anaesthetic method was used and all children received fentanyl 1 microgram kg-1 i.v. during induction. Children in group 2.0 received ketoprofen 2.0 mg kg-1 and children in group 0.5, 0.5 mg kg-1 i.v. during induction. If the child was in pain, fentanyl 1 microgram kg-1 was given i.v. as rescue analgesia. We found that ketoprofen provided good analgesia and only 49% of children required fentanyl in the post-anaesthesia care unit. There were no differences between the groups in the number of fentanyl doses, pain scores or frequency of adverse reactions. No serious adverse reactions occurred.     

Pretreatment with topical 60% lidocaine tape reduces pain on injection of propofol

We determined whether pretreatment with topical 60% lidocaine tape reduced the incidence of pain on injection of propofol compared with mixing intravenous lidocaine with propofol. In a randomized, double-blind trial, 90 patients were allocated to one of three groups: pretreatment with a bioocclusive dressing and administration of a premixed solution of propofol 180 mg and 2 mL of normal saline (Group A); pretreatment with 60% lidocaine tape and a premixed solution of propofol and normal saline (Group B); or pretreatment with a bioocclusive dressing and a premixed solution of propofol 180 mg and lidocaine 40 mg (Group C). The incidences of pain in Groups A, B, and C were 86.7%, 33.4%, and 20%, respectively. Group B and Group C had a significantly lower incidence of pain than Group A. There was no significant difference in the incidence of pain between Group B and Group C. There was no significant difference in the distribution of site of pain on injection of propofol among the three groups. Pretreatment with topical 60% lidocaine tape reduced the incidence of pain on injection of propofol similar to that of intravenous lidocaine mixed with propofol. IMPLICATIONS: Pretreatment with topical 60% lidocaine tape reduces the pain associated with injection of propofol, a frequently used intravenous anesthetic. This approach should increase patient comfort during induction of anesthesia.     

Tumour necrosis factor haplotypes and asthma

We compared the effect of infiltration with a mixture of 1 per cent lidocaine and two milligrams of morphine in twenty-five patients who were to be managed with a carpal tunnel release with the effect of infiltration with 1 per cent lidocaine only in a second group of twenty-five patients who were to have such a release. In both groups, the injection was administered after inflation of the tourniquet. During the procedure, the patients' movement and vocalization of discomfort did not differ substantially between the groups. However, in the immediate postoperative period, the patients who had received morphine indicated a significantly higher score (on a visual-analog scale) for peak intraoperative pain than did the patients who had received lidocaine only (2.44 +/- 1.73 points compared with 1.32 +/- 1.22 points; p = 0.01). The numbers of patients who had pain in the recovery room, the numbers of patients who received analgesics in the recovery room, and the scores for pain at the time of discharge were similar for the two groups. The score for pain on the first postoperative day was more than 4 points for seven patients who had received morphine, whereas no patient who had received lidocaine only had a score of more than 4 points (p = 0.01); however, the amount of analgesics taken at home was similar for the two groups. Postoperative complications, which included hypotension, fainting, weakness, and chest pain, occurred in eight patients (32 per cent) who had received morphine and in none who had received lidocaine only (p < 0.01).     

Lidocaine as a diluent for administration of benzathine penicillin G

OBJECTIVE: Benzathine penicillin G is recommended for secondary prophylaxis of rheumatic fever. Its main disadvantage is local pain and discomfort associated with the injection. Lidocaine as a diluent may reduce this discomfort. We compared the administration of benzathine penicillin G with two diluents; sterile water and lidocaine hydrochloride 1% for penicillin concentrations and pain of injection. DESIGN: In a randomized double blind, crossover trial, 18 children ages 11 to 19 years who required prophylactic treatment for rheumatic fever were randomly divided into two groups. One received an injection of benzathine penicillin G diluted with 3.2 ml of sterile water, followed 1 month later by an injection of benzathine penicillin G diluted in lidocaine hydrochloride 1%; the second group received the same regimen in the reverse order. Serum penicillin concentrations and subjective pain sensation were determined after each injection. RESULTS: Peak serum penicillin concentrations at 24 h after injection were similar for both preparations (0.100 microg/ml for water, 0.102 microg/ml for lidocaine), as were the other serum values measured throughout the month. After 28 days detectable concentrations (> or =0.020 microg/ml) were found in 44 and 291% of the subjects, respectively (P = 0.4). Urine penicillin concentrations on Day 28 were 1.81 +/- 0.25 and 2.31 +/- 0.25 microg/ml, respectively. The pain score immediately after the injection was significantly lower with the lidocaine than with the sterile water dilution. CONCLUSION: Use of lidocaine hydrochloride as a diluent for benzathine penicillin G does not change the penicillin concentration in body fluids and significantly reduces the pain of injection. We suggest the use of lidocaine hydrochloride 1% as a diluent for benzathine penicillin G.     

Paraneoplastic and oncologic profiles of patients seropositive for type 1 antineuronal nuclear autoantibodies

The association of propofol with excitatory motor activity, such as myoclonic jerking and opisthotonus, in humans and in animals suggests that it may aggravate clinical seizure activity in some circumstances, although evidence suggests that under other circumstances, propofol inhibits seizure activity. In the current study, we assessed the effect of sedating doses of propofol on lidocaine-induced seizure activity in spontaneously breathing rats receiving no other anesthetics. Adult Sprague-Dawley male rats, 300-400 g, were divided into a control group and three experimental groups representing three graded levels of propofol sedation. The control rats then received a lidocaine infusion at the rate of 150 mg x kg(-1) x h(-1), resulting in a slow, progressive increase in systemic lidocaine concentrations. At the onset of electroencephalographic (EEG) seizure activity, arterial lidocaine concentrations were obtained. The treated rats received propofol according to three different dose schedules: Dose 1 = 10 mg x kg(-1) x h(-1) after a 2.5-mg/kg bolus; Dose 2 = 20 mg x kg(-1) x h(-1) after a 5-mg/kg bolus; Dose 3 = 40 mg x kg(-1) x h(-1) after a 10-mg/kg bolus. After 30 min, a steady level of sedation, dependent on the dose of propofol, was achieved. The lidocaine infusion was then started, and systemic lidocaine levels were obtained at the onset of EEG seizure activity. The lidocaine was continued until the onset of death by cardiac arrest. Plasma lidocaine was measured by gas chromatography. Analysis of variance and Dunnett's t-test were used for comparisons with the control values. Continuous propofol sedation increased the seizure dose of lidocaine from 37.7 +/- 3.5 mg/kg (mean +/- SEM) to 52.5 +/- 2.6 mg/kg (Dose 1, P < 0.05) and 67.9 +/- 8.6 mg/kg (Dose 2, P < 0.05), and completely abolished lidocaine seizures at Dose 3. The lethal dose of lidocaine, 89.4 +/- 10.5 mg/kg control versus 108.7 +/- 10.3 mg/kg (Dose 1), 98.3 +/- 10.1 mg/kg (Dose 2), and 93.5 +/- 10.4 mg/kg (Dose 3) did not differ among groups. The lidocaine levels at seizure threshold were increased in the propofol-treated rats: 16.9 +/- 0.5 microg/mL control versus 19.2 +/- 0.7 microg/mL (Dose 1, P = not significant) and 23.7 +/- 1.8 microg/mL (Dose 2, P < 0.05). Continuous propofol sedation in spontaneously breathing rats receiving no other anesthetics exerts a protective effect against lidocaine-induced seizures in a monotonic, dose-dependent fashion. The cardiac arrest dose of lidocaine is unaffected by propofol under these conditions. IMPLICATIONS: The i.v. anesthetic drug propofol, given to rats to produce sedation, was found to suppress seizure activity caused by overdosage of the local anesthetic lidocaine.     

Increased anticoagulation during cardiopulmonary bypass by prostaglandin E1

We prospectively evaluated the diagnostic accuracy of an epinephrine-containing epidural test dose (EpiTD) as a marker of intravascular injection in 209 unmedicated laboring women. Maternal heart rate (MHR) was continuously monitored and recorded on a strip chart. A tocodynamometer monitored uterine activity. A lumbar epidural catheter was placed and aspirated. If aspiration was positive for blood or cerebrospinal fluid (CSF), the catheter was replaced. In uterine diastole and with stable MHR, 198 patients received an EpiTD (epinephrine 15 microg plus lidocaine 45 mg) via the catheter. MHR and the generated HR strip were observed. A positive EpiTD was defined as a sudden increase in MHR of 10 bpm more than the resting MHR, within one minute after the injection, with a fast acceleratory phase of more than 1 bpm. Absence of a tachycardiac response suggested a negative EpiTD. If the tachycardiac response was deemed equivocal or a uterine contraction followed the EpiTD injection within 1 min, the EpiTD was invalidated and repeated. Catheter aspiration was repeated, and the catheter was removed if aspiration was positive. All patients with negative EpiTD and aspiration received 6-12 mL of epidural bupivacaine 0.25% with or without fentanyl 50 microg. Absence of analgesia without signs or symptoms of systemic toxicity after a maximum of bupivacaine 30 mg defined failed epidural analgesia. All patients with positive EpiTD and negative aspiration received 5 mL of lidocaine 2% epidurally as a second test dose (Lido100TD). The presence of tinnitus and/or metallic taste defined a positive Lido100TD. There were 176 true negatives, 0 false negatives, 14 true positives, and 8 false positives. The sensitivity of EpiTD was 100%, the specificity 96%, the negative predictive value 100%, and the positive predictive value 63%. The prevalence of negative tests was 88%, and the prevalence of positive tests was 12%. The overall accuracy of an EpiTD was 95.5%. We conclude that EpiTD is a reliable test to identify i.v. catheters during the performance of lumbar epidural analgesia in laboring patients. Implications: Catheters inserted for epidural analgesia in laboring patients may accidentally enter a blood vessel. Local anesthetics injected through these catheters may cause seizures and cardiac arrest. In this study, we concluded that injecting a small amount of epinephrine before injecting a local anesthetic frequently helps to identify these misplaced catheters. Few catheters may actually be in the correct place even after responses to epinephrine.     

Congenital syphilis: detection of Treponema pallidum in stillborns

We have investigated the analgesic and opioid sparing effect of perioperative i.v. ketoprofen in a randomized, double-blind, placebo-controlled, parallel group study in 164 children, aged 1-7 yr, after adenoidectomy. A standard anaesthetic method was used and all children received fentanyl 1 microgram kg-1 i.v. during induction. Children in the ketoprofen group received ketoprofen 1 mg kg-1 i.v. after induction of anaesthesia followed by an infusion of ketoprofen 1 mg kg-1 over 2 h. Children in the placebo group received 0.9% saline. All children received fentanyl 1 microgram kg-1 i.v. as rescue analgesia. In the ketoprofen group less children required postoperative fentanyl (64% vs 77%, P = 0.006) and the total number of fentanyl doses was smaller compared with the placebo group (mean 1.0 (SD 1.1) (95% confidence intervals (CI) 0.8-1.3) vs 1.5 (1.1) (95% CI 1.2-1.7), P = 0.012). Worst pain observed in the postanaesthesia care unit was also lower in the ketoprofen group both at rest (P = 0.028) and during swallowing (P = 0.001). There were no difference in the number of adverse reactions between the groups. No serious adverse reactions occurred.     

The influence of the bolus injection rate of propofol on its cardiovascular effects and peak blood concentrations in sheep

The influence of the bolus injection rate of propofol on its cardiovascular effects has not been extensively studied. We therefore examined the influence of the injection rate of i.v. bolus doses of propofol on its acute cardiovascular effects and peak blood concentrations in seven chronically instrumented sheep. Each received i.v. propofol (200 mg) over 2 min (slow injection) and 0.5 min (rapid injection) on separate occasions in random order. The rapid injection was associated with more profound decreases in mean arterial blood pressure than slow injection (35.7% vs 23.7% maximal reductions from baseline, respectively; P = 0.02). There were no significant differences between the injection rates for peak reductions in myocardial contractility, increases in heart rate, or degree of respiratory depression. Concurrently, the rapid injections were associated with significantly higher arterial (26.9 vs 11.9 mg/L) propofol concentrations in a manner consistent with indicator dilution principles. There were no differences in the peak coronary sinus concentrations between the injection rates. We conclude that the rapid injection of propofol in the context of the induction of anesthesia produced significantly higher peak arterial propofol concentrations and suggest that it is these higher concentrations that produced relatively greater reductions in arterial blood pressure from rapid injections. Implications: Propofol is injected into a vein to initiate anesthesia. It can cause a rapid decrease in blood pressure, which may be dangerous to the patient. We examined the effect of rapid and slow injection rates of propofol in sheep and found that rapid injection caused a greater decrease in blood pressure. This was because rapid injection caused higher concentrations of propofol in the blood immediately after the injection. We believe that if the same processes occur in humans, there may be little advantage in injecting propofol rapidly.     

Intradermal anaesthesia: comparison of several compounds

OBJECTIVE: To compare the efficacy of different local anaesthetics to produce intradermal anaesthesia for venous cannulation and the discomfort associated with skin infiltration. DESIGN: Randomized, double blind study. SETTING: Induction room of a university hospital. PATIENTS: Convenience sample of 600 patients (18-65 years; ASA I-II) scheduled for elective surgery. INTERVENTIONS: Patients received one of six preparations: 0.9% saline, 1% prilocaine (Xylonest), 1% lidocaine (Xylocain), 1% mepivacaine-1 (Meaverin), 1% mepivacaine-2 (Scandicain), 1% procaine (Novocain). A skin wheal was raised on the dorsum of the hand by injecting 0.1 ml intradermally and 0.1 ml subcutaneously via a 27-g hypodermic needle. 60 seconds later an 18-g intravenous cannula was passed through that skin wheal into a vein. MEASUREMENTS: A visual analog scale (VAS) for pain (0 = no pain/10 = most pain imaginable) was used to assess pain elicited by raising the skin wheal and inserting the cannula. MAIN RESULTS: With regard to analgesic potency all five local anaesthetics were comparable (mean VAS-score 1.7-2.09) and effective when compared to 0.9% saline (mean VAS-score 4.2; P < 0.001). Infiltration pain was least with mepivacaine-1 (mean VAS-score 1.0; P < 0.001) and highest with procaine (mean VAS score 2.7; P < 0.001). CONCLUSIONS: Of the local anaesthetics tested, Mepivacaine-1 is the drug of choice for skin infiltration as its injection elicits least discomfort.     

Upper airway reflexes during a combination of propofol and fentanyl anesthesia

BACKGROUND: The effects of intravenous anesthetics on airway protective reflexes have not been fully explored. The purpose of the present study was to characterize respiratory and laryngeal responses to laryngeal irritation during increasing doses of fentanyl under propofol anesthesia. METHODS: Twenty-two female patients anesthetized with propofol and breathing through the laryngeal mask airway were randomly allocated to three groups: (1) eight patients who received cumulative total doses of 200 microg fentanyl given in the form of two doses of 50 microg and one dose of 100 microg spaced 6 min under mechanical controlled ventilation while end-tidal carbon dioxide tension (PCO2) was maintained at 38 mmHg (fentanyl-controlled ventilation group), (2) eight patients who received cumulative total doses of 200 microg fentanyl while breathing spontaneously while end-tidal PCO2 was allowed to increase spontaneously (fentanyl-spontaneous ventilation group), and (3) six spontaneously breathing patients who were anesthetized with propofol alone (propofol group). The laryngeal mucosa of each patient was stimulated by spraying the cord with distilled water, and the evoked responses were assessed by analyzing the respiratory variables and endoscopic images. RESULTS: Before administration of fentanyl, laryngeal stimulation caused vigorous reflex responses, such as expiration reflex spasmodic panting, cough reflex, and apnea with laryngospasm. Increasing doses of fentanyl reduced the incidences of all these responses, except for apnea with laryngospasm, in a dose-related manner in both the fentanyl-controlled ventilation and the fentanyl-spontaneous ventilation groups. Detailed analysis of endoscopic images revealed several characteristics of laryngeal behavior during the airway reflex responses. CONCLUSION: Incremental doses of fentanyl depress airway reflex responses in a dose-related manner, except for apnea with laryngospasm.     

Intraarterial vs intravenous administration of antivenin for the treatment of Crotalidae atrox envenomation: a pilot study

OBJECTIVE: Standard therapy for significant snake envenomation includes antivenin. i.v. administration is currently the only recommended route. Intraarterial (i.a.) administration has potential advantages over i.v. that could improve outcome. To study this, the authors compared i.v. and i.a. antivenin administrations for the treatment of experimental snake envenomations. METHODS: 14 adult female swine were anesthetized and prepared with femoral artery and ear vein catheters, and baseline hoof, forearm, and thigh circumference and volume displacement measurements were taken. Crotalidae atrox venom was injected into the subcutaneous tissue of the hoof. The doses of venom were 4.75, 9.50, 19.00, 37.90, 47.30, 56.90, and 66.40 mg. Immediately following injection of venom, polyvalent antivenin (Crotalidae) (0.285 mg/10 mL saline) was infused over 30 minutes into the femoral artery (i.a. group) or ear vein (i.v. group). As a control, 10 mL of saline was infused into the ear vein (i.a. group) or femoral artery (i.v. group). Measurements were recorded up to 48 hours. Linear mixed-effect regression models were used for each measurement and to compare the i.a. and i.v. groups. RESULTS: Venom dose and time after administrations were associated with increased circumferences and increased volumes (p < 0.05). i.v. administration was associated with larger hoof (1.26 cm) and forearm (0.42 cm) sizes and volume displacement (21.71 mL) when compared with i.a. administration ( p < 0.05). CONCLUSION: i.a. antivenin results in a modest but significant decrease in tissue edema when compared with i.v..     

Effectiveness of polyclonal and monoclonal antibodies prepared for an immunoassay of the etofenprox insecticide

The aim of this study was to compare hemodynamic responses to intubation and pin head-holder application in two groups of neurosurgical patients given oral clonidine (3 microg/kg) or oral temazepam (10-20 mg) 90 min before the induction of anesthesia. Fifty patients undergoing elective craniotomy were randomized to either group. Anesthesia was induced with i.v. propofol 1500 mg/h, fentanyl 4 microg/kg, vecuronium 0.15 mg/kg, and lidocaine 1.5 mg/kg and was maintained with propofol 6 mg x kg(-1) x h(-1). Mean arterial blood pressure (MAP) and heart rate were recorded before the induction of anesthesia and before and after intubation and application of the pin head holder. Interventions required to maintain hemodynamic stability were compared between groups. Preinduction sedation scores and MAP values were similar between groups. MAP was significantly lower (P = 0.031) in the clonidine group after pin head-holder application. Interventions to stabilize MAP were not significantly different between groups (P = 0.11). We conclude that clonidine is effective in reducing the MAP increase with pin head-holder application in patients undergoing craniotomy. Implications: In this study, we investigated an approach to the prevention of increased blood pressure often seen during the early part of anesthesia for brain surgery. Oral clonidine was effective in reducing the mean arterial blood pressure increase resulting from pin head-holder application. Clonidine, a blood pressure-reducing drug, was given to 25 patients before anesthesia. Their blood pressure measurements were then compared with those of 25 patients not given clonidine.     

Propofol-air-oxygen anesthesia reduces the incidence of sore throat after laryngeal mask anesthesia

We investigated the effects of the presence or absence of N2O in propofol anesthesia using a laryngeal mask on the incidence of postoperative sore throat. In the N2O-combined anesthesia group (n = 25), score 0 (no sore throat) was observed in 11 patients; score 1 (slight pain and discomfort that improved on the next day of operation) in 9; and score 2 (persistent pain on the next day) in 5. In the non-N2O-combined anesthesia group (n = 25), score 0 was observed in 21 patients, score 1 in 3; and score 2 in 1, showing a significantly lower incidence of sore throat and milder sore throat than in the N2O-combined anesthesia group. These results suggest that propofol anesthesia using a laryngeal mask not combined with N2O reduces the incidence of postoperative sore throat.     

Expression of LECAM-1 and LFA-1 on pre-B lymphoma cells but not on preneoplastic pre-B cells in SL/KH mice

BACKGROUND AND OBJECTIVES: The efficacy of operatively administered spinal neostigmine to provide analgesia and that of different antiemetics to prevent neostigmine-related nausea and vomiting were evaluated in patients undergoing tibial or ankle reconstruction. METHODS: One hundred patients were randomized to five groups (n = 20). The intravenous antiemetic test drug (except propofol) was given as premedication in the holding room, after intravenous midazolam, 0.05 mg/kg. The subarachnoid drugs administered were 20 mg bupivacaine (0.5%) in conjunction with 100 micrograms neostigmine, except for the saline group (S group), which received bupivacaine and saline. The S group, the neostigmine group (N group), and the propofol group (P group) received saline as the intravenous test drug. The droperidol group (D group) received intravenous droperidol 0.5 mg, and the metoclopramide group (M group) received intravenous metoclopramide 10 mg. The P group had a continuous intravenous propofol infusion (2-4 mg/kg/hr), started 10 minutes after the spinal injection. Nausea, emetic episodes, and the need for analgesic (disclofenac) or antiemetic medication were recorded for the first 24 hours following surgery and scored by a 10-cm visual analog scale (VAS). RESULTS: Subarachnoid neostigmine 100 micrograms did not affect subarachnoid bupivacaine analgesia as measured by time to first rescue analgesic in most patients, but it decreased the overall 24-hour visual analog scale (VAS) scores and the need for postoperative analgesics in 24 hours (P < .001). The incidence of intraoperative nausea and vomiting was higher in the N, D, and M groups than in the S group (P < .001). Following surgery, the 3-hour VAS assessment for emesis was higher for the N, P, and M groups than for the S group (P < .05). The overall 24-hour assessment was similar among groups. CONCLUSIONS: Subarachnoid neostigmine reduced postoperative pain scores and analgesic requirements. Whether it prolonged the duration of action of diclofenac or enhanced the mechanisms involved in spinal analgesia cannot be determined from these data. Although propofol and droperidol appeared to be more effective during and after surgery, respectively, all neostigmine groups were associated with a high consumption of antiemetics.     

Pre- versus postinjury effects of intravenous GABAergic anesthetics on formalin-induced Fos immunoreactivity in the rat spinal cord

We evaluated the suppression of spinal Fos-like immunoreactivity (FLI) by i.v. anesthetics in the rat formalin model. Preformalin injection (1.5% subcutaneously) treatment groups included i.v. saline controls and three i.v. GABAergic anesthetic groups (pentobarbital 20 mg/kg, propofol 10 mg/kg, or alphaxalone 1.5 mg/kg; n = 12 per group). After perfusion 2 h postformalin, spinal cords were dissected, sliced at 30 microm, and processed by immunoperoxidase staining with an antibody against the Fos protein. Quantification and determination of the laminar distribution of Fos-labeled nuclei were performed at the L4-5 spinal level ipsilateral to formalin injection. Drug groups demonstrating FLI suppression were comparatively studied in a 5-min postformalin treatment group. Pentobarbital pretreatment failed to suppress FLI. However, significant reductions (percent decrease) of FLI were observed with propofol (63%) and alphaxalone (30%) compared with saline controls. Pre- versus postformalin comparison studies showed that propofol, but not alphaxalone, suppressed FLI more effectively when given preformalin. Given the observed inconsistencies between this study of Fos expression and our previous behavioral study, it is questionable whether anesthetic modulation of noxious stimulus-induced FLI parallels that of behavioral responses. Implications: In this study, we examined whether i.v. general anesthetics (propofol, alphaxalone, and pentobarbital) prevent injury-induced spinal cord changes. We measured spinal Fos protein after rats received anesthetics before versus after a formalin injection. Fos inhibition patterns were inconsistent with behavioral studies of these anesthetics, suggesting that Fos inhibition does not always correlate with behavioral analgesia.     

Capacity of the clinical picture to characterize low back pain relieved by facet joint anesthesia. Proposed criteria to identify patients with painful facet joints

STUDY DESIGN: Prospective randomized study to compare the efficacy of facet joint injection with lidocaine and facet joint injection with saline in two groups of patients with low back pain, with and without clinical criteria that were determined in a previous study to implicate the facet joint as the primary source of the pain. OBJECTIVES: To assess the efficacy of single facet joint anesthesia versus placebo (saline injections) and to determine clinical criteria that are predictive of significant relief of LBP after injection. SUMMARY OF BACKGROUND DATA: There is no syndrome that discriminates between lower back pain caused by facet joint and that caused by other structures. Single or double facet joint anesthesia, and single photon emission computed tomography are expensive and time-consuming procedures for selecting patients in controlled clinical trials with large populations. METHODS: Results of a previous study showed that seven clinical characteristics were more frequent in patients who responded to facet joint anesthesia than in those who did not. In the current study, a group of 43 patients with lower back pain who met at least five criteria were compared with 37 patients who met fewer criteria. Patients randomly received injection of either lidocaine or saline into the lower facet joints. The result was considered positive if more than 75% pain relief was determined by visual analog scale. The patient, the radiologist, and the investigator were blinded. An analysis of variance was used to seek an interaction between clinical group effect and injection effect, and logistic regression analysis to select the best set of variables that would be predictive of minimum pain relief of 75% after the injection. RESULTS: There was a significant interaction between clinical group and injection effect (P = 0.003). In patients with back pain, lidocaine provided greater lower-back pain relief than saline (P = 0.01). Lidocaine also-provided greater pain relief in the back pain group than in the nonpain group (P = 0.02). The presence of five among seven variables (age greater than 65 years and pain that was not exacerbated by coughing, not worsened by hyperextension, not worsened by forward flexion, not worsened when rising from flexion, not worsened by extension-rotation, and well-relieved by recumbency), always including the last item, distinguished 92% of patients responding to lidocaine injection and 80% of those not responding in the lidocaine group. CONCLUSIONS: A set of five clinical characteristics can be used in randomized studies to select lower back pain that will be well relieved by facet joint anesthesia. These characteristics should not, however, be considered as definite diagnostic criteria of lower back pain originating from facet joints.