Intravenous ketamine attenuates arterial pressure changes during the induction of anaesthesia with propofol

BACKGROUND AND OBJECTIVE: To investigate whether the administration of ketamine before induction with propofol produces a smaller decrease in arterial pressure. METHODS: Twenty-two patients were assigned to one of two groups to receive either propofol with ketamine (n = 11) or propofol alone (n = 11, control). Anaesthesia was induced with 2 mg kg-1 propofol and 0.5 mg kg-1 ketamine or 2 mg kg-1 propofol alone. Ketamine was administered 1 min prior to induction with propofol. Immediately after induction with propofol, vecuronium (0.15 mg kg-1) was administered. Four minutes after administration of vecuronium, tracheal intubation was performed. Anaesthesia was maintained using sevoflurane (0.5%) in 66% nitrous oxide until 3 min after intubation. Systolic, diastolic and mean arterial pressure and heart rate were recorded on arrival, directly before induction with propofol, prior to tracheal intubation, immediately after intubation and at 3 min after intubation. RESULTS AND CONCLUSIONS: Administration of ketamine before induction with propofol preserved haemodynamic stability compared with induction with propofol alone.     

Epidural anesthesia with lidocaine reduces propofol injection pain

PURPOSE: To determine whether epidural lidocaine reduces the severity of propofol injection pain compared with iv lidocaine. METHODS: A prospective, randomized double-blind clinical study was conducted in 120 female patients scheduled for elective gynecological laparotomy. A lumbar epidural catheter and an iv catheter placed in the cephalic vein of the non-dominant hand were used in all patients. Patients of the control group (Group C) were given epidural normal saline followed by iv normal saline then iv propofol. Patients of Group E were given epidural 2% lidocaine (0.08 mL.cm(-1)) followed by iv normal saline and then propofol. Patients of Group V were given epidural normal saline followed by iv 2% lidocaine (0.05 mL.kg(-1)) then propofol. Pain was scored as no pain=0, minimal pain=1, moderate pain=2, severe pain=3. RESULTS: The pain scores, in group E; 1 (0-2) and group V; 2 (0-2), were significantly lower than in group C; 2 (1-3); median (25th-75th percentile) (P <0.001). There was no difference in pain score between groups E and V The plasma lidocaine concentration 15 min after epidural lidocaine was 2.74 +/- 0.54 microg.ml(-1), compared with 1.54 +/- 0.31 microg.mL(-1) at three minutes after iv lidocaine. CONCLUSION: Epidural and iv lidocaine equally reduced the severity of propofol injection pain despite higher lidocaine plasma concentrations in epidurally administered lidocaine.     

Propofol-induced injection pain: comparison of a modified propofol emulsion to standard propofol with premixed lidocaine

Propofol is well known for its association with pain on injection. The most frequently used method to reduce this pain is premixture with lidocaine. Recently, a modified lipid emulsion of propofol containing medium-chain triglycerides (MCT) with long-chain triglycerides (LCT), in contrast to the usual LCT formulation, has been advocated to alleviate pain. In a randomized, prospective, controlled, double-blind study on 222 surgical patients, we compared the effect of the two solutions on the incidence and intensity of injection pain. Patients were randomly allocated to receive either propofol MCT/LCT (group M; n = 109) or standard propofol LCT with the addition of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of propofol (group L; n = 113). Pain scores were assessed using a verbal analog scale (VAS) ranging from 0-10. Group L was found to have significantly less pain on the injection of propofol (mean VAS, 2.5 +/- 2.9) (mean +/- sd) than group M (mean VAS, 3.8 +/- 3.2; P = 0.002). Regarding postoperative recall of pain on injection, patients in group L indicated significantly less pain (mean VAS, 2.2 +/- 2.4) than patients in group M (mean VAS, 3.0 +/- 2.7; P = 0.02). Premixing of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of standard propofol LCT causes less pain on injection than propofol MCT/LCT and thus increases patient comfort.     

麻醉诱导期间异丙酚与利多卡因的相互作用

目的探讨麻醉诱导期间不同利多卡因浓度对睫毛反射、意识消失时异丙酚血药浓度和心血管系统的影响。方法选择38例择期手术病人应用微机控制靶控输注利多卡因维持不同目标浓度(Ct)，其后从另一接口输注异丙酚，逐渐增加异丙酚目标浓度直至意识消失。根据利多卡因目标浓度将病人分为5组，分别为A组Oug·ml     

Iontophoretically applied lidocaine and the prevention of pain associated with the injection of intravenous propofol: a comparison with intravenous lidocaine

BACKGROUND AND OBJECTIVE: Pain following the injection of propofol is a common problem. It is often treated by the coadministration of intravenous lidocaine. Iontophoresis, which facilitates the delivery of charged molecules such as lidocaine to body tissues, may be a practical alternative to lessen the pain. METHODS: The iontophoretic application of lidocaine was compared with intravenous lidocaine to assess the relative efficacy of reducing pain during propofol administration. RESULTS: The incidence rate of moderate or severe pain was significantly greater in the iontophoresis group (26.7 compared with 6.9% in the intravenous lidocaine group) (P < 0.05). CONCLUSIONS: The iontophoretic administration of lidocaine 60 mg does not compare favourably with lidocaine 40 mg mixed with propofol for the reduction of pain on administration of propofol.     

Computer simulation of intracranial pressure changes during induction of anesthesia: comparison of thiopental, propofol, and etomidate

We have developed a computer model of cerebrovascular hemodynamics that interacts with a pharmacokinetic drug model. We used this model to examine the effects of various stimuli occurring during anesthesia on cerebral blood flow (CBF) and intracranial pressure (ICP). The model is a seven-compartment constant-volume system. A series of resistances and compliances relate blood and cerebrovascular fluid fluxes to pressure gradients between compartments. Variable arterial-arteriolar resistance (Ra-ar) and arteriolar-capillary resistance (Rar-c) simulate autoregulation and drug effects, respectively. Rar-c is also used to account for the effect of CO2 on the cerebral circulation. A three-compartment pharmacokinetic model predicts concentration-time profiles of intravenous induction agents. The effect-site compartment is included to account for disequilibrium between drug plasma and biophase concentrations. The simulation program is written in VisSim dynamic simulation language for an IBM-compatible personal computer. Using the model, we have predicted ICP responses during induction of anesthesia for a simulated patient with normal as well as elevated ICP. Simulation shows that the induction dose of intravenous anesthetic reduces ICP up to 30% (propofol > thiopental > etomidate). The duration of this effect is limited to less than 5 minutes by rapid drug redistribution and cerebral autoregulation. Subsequent laryngoscopy causes acute intracranial hypertension, exceeding the initial ICP. ICP elevation is more pronounced in a nonautoregulated cerebral circulation. Simulation results are in good agreement with the available experimental data. The presented model allows comparison of various drug administration schedules to control ICP.     

Preventing pain during injection of propofol: effects of a new emulsion with lidocaine addition

BACKGROUND AND OBJECTIVE: Previous studies found that lidocaine addition to propofol long-chain triglyceride was associated with a lower incidence of injection pain than medium-chain triglyceride/long-chain triglyceride formulation, but the incidence was still high (31-40%). Our study investigated whether the incidence of injection pain could be further reduced by the addition of lidocaine (10 mg, 20:1) to propofol medium-chain triglyceride/long-chain triglyceride. METHODS: In a randomized double-blind controlled trial 464 patients scheduled to undergo regional anaesthesia were assigned to receive one of the following four options: propofol medium-chain triglyceride/long-chain triglyceride + lidocaine, propofol long-chain triglyceride + lidocaine, propofol medium-chain triglyceride/long-chain triglyceride or propofol long-chain triglyceride. Propofol was injected to reach grade 3 of the Observer's Assessment of Alertness/Sedation scale. RESULTS: Incidence of injection pain was 18% in the propofol medium-chain triglyceride/long-chain triglyceride + lidocaine group, 31% in the propofol long-chain triglyceride + lidocaine group, 47% in the propofol medium-chain triglyceride/long-chain triglyceride group and 60% in the long-chain triglyceride group. Propofol medium-chain triglyceride/long-chain triglyceride + lidocaine was associated with a statistically significant reduced incidence of injection pain compared with propofol long-chain triglyceride +lidocaine (P =0.0249, number needed to treat =7.7). CONCLUSIONS: Premixing propofol medium-chain triglyceride/long-chain triglyceride with lidocaine is one of the most effective measures currently available to reduce the incidence of injection pain in sedated patients during regional anaesthesia.     

The effect of lidocaine on the bispectral index during anesthesia induction with propofol]

We investigated the effect of premixing lidocaine with propofol on a bispectral index (BIS) during propofol infusion. We studied 40 adult patients given mixture of 1% propofol 20 ml with 2 ml of normal saline (control group) or 2% lidocaine (lidocaine group) infused at 2 ml.kg-1.hr-1 for 10 minutes. Heart rate, mean arterial pressure, and BIS were measured every minute. The addition of lidocaine to propofol reduced the incidence of injection pain from 85% to 10% but did not change the induction time. Propofol significantly decreased mean arterial pressure and BIS but there was no difference between the groups. In conclusion, premixing lidocaine with propofol reduces injection pain without affecting the hypnotic effect.     

Clonidine versus ketamine to prevent tourniquet pain during intravenous regional anesthesia with lidocaine

BACKGROUND AND OBJECTIVES: Both clonidine and ketamine have been found to prolong the action of local anesthetics through a peripheral mechanism. Our study compares the efficacy of a low dose of clonidine or ketamine separately added to intravenous regional anesthesia (IVRA) with lidocaine to prevent tourniquet pain. METHODS: We conducted a prospective randomized double-blinded study in 45 patients undergoing hand or forearm surgery, with anticipated duration exceeding 1 hour under IVRA. Proximal cuff inflation of a double tourniquet was followed by administration of 40 mL of lidocaine 0.5% and either saline, 1 microg/kg clonidine, or 0.1 mg/kg ketamine. When anesthesia was established, the inflation of the proximal and distal cuff was interchanged. Thereafter, tourniquet pain was rated on a visual analog scale (VAS) every 10 minutes. Intraoperatively, boluses of 25 microg fentanyl were provided for tourniquet pain treatment when required, and total fentanyl consumption was recorded. RESULTS: Patients receiving plain lidocaine persistently reported the highest pain scores among groups (P <.001) 20 minutes after distal cuff inflation. Differences between the groups with additional treatment were noted 50 minutes after distal cuff inflation and until the end of the observation, with significantly lower VAS ratings (P <.001 to P <.01) in ketamine-treated patients. Total fentanyl consumption was significantly decreased by ketamine (70.00 +/- 25.35 microg) or clonidine (136.67 +/- 39.94 microg) compared with the plain lidocaine group (215.33 +/- 52.33 microg) (P <.001 between all groups). CONCLUSIONS: The addition of clonidine 1 microg/kg or ketamine 0.1 mg/kg to lidocaine for IVRA delays the onset of unbearable tourniquet pain and decreases analgesic consumption for tourniquet pain relief, although ketamine has a more potent effect.     

Prevention of pain on injection with propofol in children: comparison of nitrous oxide with lidocaine

INTRODUCTION: Injection pain caused by propofol is an important disadvantage, especially in children, incompletely reduced by adding lidocaine intravenously. Nitrous oxide's analgesic effects, well known, have never been evaluated on pain due to propofol. OBJECTIVE: To compare the effects of nitrous oxide with lidocaine on pain on injection caused by propofol in children. STUDY DESIGN: Double blind, randomised, prospective study. PATIENTS AND METHODS: 48 children aged more than 5 were randomly allocated to one of the 2 groups: N2O group, breathed 50% N2O + 50% O2 than received propofol only and Lido group breathed 100% O2 and received a mixture of propofol with lidocaine. The possible pain was scored during injection by a behavioural scale and once again in the recovery room by the child himself with a VAS. RESULTS: There was no significant difference in behavioural pain scores among the 2 groups; pain was assessed as being moderate or severe in 6/24 patients in N2O group and 10/24 in Lido group (behavioural scores > 1). Significantly more children in the N2O group had low VAS scores compared with the Lido group (no child/24 scored a VAS > 4 and 7/23 in the Lido group) demonstrating that N2O amnesic effects would omit the memory of pain caused by propofol. CONCLUSION: The use of nitrous oxide is an easy, cheap and efficient method to reduce the incidence of pain injection of propofol and his amnesic effects can provide real advantages in paediatric anaesthesia.     

The peripheral analgesic effect of tramadol in reducing propofol injection pain: a comparison with lidocaine.

BACKGROUND AND OBJECTIVES: Tramadol and metoclopramide have a local anesthetic effect similar to lidocaine following intradermal injection. When metoclopramide was retained in the venous system for 1 minute, it was found to be as effective as lidocaine in reducing propofol injection pain. Using this metoclopramide model, the effects of tramadol in reducing pain on propofol injection was investigated. METHODS: One hundred five patients were randomly allocated to receive 50 mg tramadol (group T), 60 mg lidocaine (group L), or normal saline (group NS) as pretreatment to reduce pain on propofol injection. Following venous occlusion with a tourniquet (70 mm Hg), one of the drugs was intravenously administered. Venous retention of the drug was maintained for 1 minute. Immediately after the tourniquet release, intravenous injection of 100 mg propofol (10 mL) at a rate of 0.5 mL/s followed. Pain assessment was made after each injection. RESULTS: Transient minor injection pain and local skin reactions were significantly greater with tramadol than with lidocaine (P < .05). Both tramadol and lidocaine significantly reduced the incidence and intensity of propofol injection pain when compared with normal saline (P < .05). CONCLUSIONS: Using -minute retention in veins, both tramadol and lidocaine significantly reduced propofol injection pain. A local anesthetic activity is postulated.     

Middle-ear pressure variations during total intravenous anesthesia with propofol, fentanyl, and ketamine

Purpose As the middle-ear cavity is one of the noncompliant gas-filled cavities, an increase in middle-ear pressure (MEP) instead of volume expansion is observed with inhalation of nitrous oxide (N₂O). Changes in MEP cause many complications, such as ear pain, temporary hearing impairment, and postoperative emesis. Therefore, we investigated changes in MEP during total intravenous anesthesia (TIVA) with propofol, fentanyl, and ketamine (PFK) and inhalation of N₂O. Methods Twelve patients were anesthetized with PFK until 60 min after the induction of anesthesia, and then N₂O (60%) inhalation was started. MEP was measured by impedance audiometry (ranging from −300 daPa to +200 daPa) at 10-min intervals during PFK, and at 2-min intervals after the inhalation of N₂O. Results MEP gradually but significantly increased from the preanesthetic value of 16±8 to 34±12 (SEM) daPa 50 min after the induction of PFK. However, MEP did not exceed the normal limit. The values of MEP in all patients were more than 200 daPa within 36 min after the start of inhalation of N₂O in oxygen. Conclusion PFK had a minimal effect on MEP, whereas addition of N₂O to PFK increased MEP dramatically. Therefore, TIVA, or at least PFK, would be a better choice for patients with middle-ear or upper-airway diseases.     

Pain on injection of propofol: comparison of metoprolol with lidocaine

BACKGROUND AND OBJECTIVE: Pain is often experienced when propofol is injected, and intravenous lidocaine is often effective in preventing such pain. We decided to determine whether metoprolol, given before the injection of propofol, is as effective as lidocaine in reducing the incidence and severity of the pain. METHODS: Ninety patients scheduled for elective surgery under general anaesthesia were randomly allocated to one of three groups to receive either metoprolol 2 mg, lidocaine 20 mg or saline 2 mL before any propofol was injected. Each patient was given one of these agents intravenously via a 20-G cannula on the dorsum of the hand whilst the venous drainage was occluded manually, at the middle of the forearm, for 45 s. After the occlusion was released, propofol 2.0-2.5 mg kg(-1), at room temperature, was injected at 2 mL (20 mg) every 4 s. Pain was assessed verbally and scored as none (0), mild (1) or severe (2). RESULTS: The incidence of severe pain in the control group (56.7%) was significantly higher than in the metoprolol and lidocaine groups (16.6 and 10%, respectively). The number of patients who were free of pain was significantly higher in those who had been given either metoprolol or lidocaine. CONCLUSIONS: Pretreatment with intravenous metoprolol was equally as effective as lidocaine in reducing the pain associated with propofol injection.     

Painless injection of propofol: pretreatment with ketamine vs thiopental, meperidine, and lidocaine

Propofol, a commonly used anesthetic, often causes pain on injection. Several methods have been described to reduce this pain, however, complete inhibition has not been achieved. Our randomized, placebo controlled, double blind study has been conducted to compare the analgesic efficacy of iv pretreatment of ketamine, meperidine, thiopental, lidocaine to minimize the injection pain of propofol. 125 patients ASA I and II were randomly allocated into 5 groups and received. Group K, ketamine 0.4 mg/kg; Group T, thiopental 0.5 mg/kg; Group M, meperidine 0.5 [corrected] mg/kg; Group L, lidocaine 1 mg/kg; Group S, saline 3 ml. All pretreatment drugs were made into 4 ml solutions and were accompanied by manual venous occlusion for 1 min, followed by tourniquet release and slowly IV administration of propofol. Pain was assessed with a four point scale. All treatment groups had a significantly lower incidence of pain than placebo group (p <0.05). However, it has been observed that pretreatment with ketamine was the most effective in attenuating pain associated with propofol injection (p <0.05). For painless injection of propofol, routine pretreatment with ketamine 0.4 mg/kg along with venous occlusion is recommended.