The injection pain of propofol with different emulsion

BACKGROUND: Incidence and intensity of pain on intravenous injection of propofol were assessed with emulsion of long-chain/medium-chain triglycerides (LCT/MCT, 50: 50) and only long-chain triglycerides (LCT, 100) in patients undergoing different elective surgical interventions in this prospective, randomized, cross over and double-blinded study. METHODS: 1) Forty six patients were assigned to two groups. One group received 0.2 mg x kg(-1) LCT/ MCT propofol prior to LCT propofol administration. The other group received 0.2 mg x kg(-1) LCT propofol prior to LCT/MCT propofol administration. Pain elicited upon questioning was assessed with each injection in the two groups. Patients were asked to grade the pain as VAS of 0 to 100 mm. 2) Fifty one patients were randomly assigned to two groups. One group received 0.4 mg x kg(-1) LCT propofol. The other group received 0.4 mg x kg(-1) LCT/MCT propofol. Patients were asked to grade the pain as VAS of 0 to 100 mm. RESULTS: Pain of LCT propofol injection was stronger than LCT/MCT propofol. As incidence of 0.4 mg x kg(-1) propofol injection, VAS on LCT/MCT propofol and LCT propofol gave score as 0 and 23.5 (P=0.0019). CONCLUSIONS: Propofol with emulsion of long- and medium-chain triglycerides appears to reduce the injection pain than with emulsion of only long-chain triglycerides.     

Pain on injection: a double-blind comparison of propofol with lidocaine pretreatment versus propofol formulated with long- and medium-chain triglycerides

The incidence of pain on injection of propofol has been reported to be 70%. A new propofol formulation with a 10% emulsion of long- and medium-chain triglycerides (LCT/MCT) is associated with less pain on injection. Our goal was to compare the effect of propofol-LCT/MCT on the incidence of pain versus propofol with lidocaine 40 mg IV pretreatment injected as a Bier's block. Two hundred healthy women scheduled for ambulatory gynecological procedures were allocated to 1 of 2 groups in a randomized double-blind fashion. Group LIDO received lidocaine 2% 2 mL injected with a tourniquet 1 min before propofol 1% 2 mg/kg IV; group LCT/MCT received NaCl 0.9% 2 mL with tourniquet 1 min before propofol-LCT/MCT 1% 2 mg/kg IV. Spontaneous verbal expressions of pain, movement of hand, frowning, and moaning during the injection were recorded. The incidence and severity of pain were assessed 30 min and 6 h after surgery. Recall of pain was considered with a visual analog scale (VAS) score >1, and pain was graded as VAS 0-10. More women reported spontaneous verbal expression of pain with propofol-LCT/MCT (47% versus 24%; P = 0.0014; relative risk 1.61 [95% confidence interval, 1.22-2.13]). Among women with a painful injection, there was no difference after surgery regarding the intensity of pain or recall of pain. In contrast to previous reports, we found that propofol-LCT/MCT resulted in a more frequent incidence of pain than propofol 1% with IV lidocaine pretreatment. This may be due to the diversity of pain definitions used in studies or to the lack of premedication in our study.     

Comparison of propofol LCT and propofol MCT/LCT regarding the injection pain at different sites and the memory

BACKGROUND: Incidence and intensity of pain on intravenous injection of propofol LCT were compared with those of propofol MCT/LCT. METHODS: Eighty adult patients scheduled to receive general anesthesia were divided into two groups, propofol LCT (Group L, AstraZeneca) and propofol MCT/LCT (Group M, Maruishi Pharmaceutical). The peripheral vein was inserted with an 18 gauge intravenous catheter at the dorsal hand, the wrist, or the anterior brachial region. Propofol 2.0 mg x kg(-1) was injected at the speed of 5 mg x sec(-1). Noninvasive arterial blood pressure, heart rate, a BIS value and a degree of pain were measured. We used chi2 analysis and Wilcoxon t-test for statistical evaluation. RESULTS: There was a significantly larger incidence of injection pain in the Group L than the Group M (70% vs. 30%). The pain at the brachial region was significantly less as compared with the wrist or the dorsal hand in both groups. The ratio of patients having the memory of pain on the next day to those complaing the injection pain was 50% in the Group L and 36% in the Group M. There were no significant differences between the two groups in changes in BIS values and doses of propofol necessary for the loss of consciousness. CONCLUSIONS: The results suggest that propofol MCT/LCT elicits less pain on injection than propofol LCT. The injection pain is less at the brachial region than the wrist or the hand. Amnesia of pain may be obtained both with propofol MCT/ LCT and propofol LCT.     

Evaluation of low-dose propofol preadministration to attenuate vascular pain during induction of anesthesia

STUDY OBJECTIVE: To determine whether a small dose of propofol before induction decreases pain with injection using two different formulas of propofol-10% long-chain triglycerides (LCT) and medium-chain triglycerides (MCT) and LCT. DESIGN: Prospective, randomized, comparative study. SETTING: University-affiliated hospital. PATIENTS: 200 ASA physical status I and II patients. INTERVENTIONS: Group A (LCT control) and group B (MCT/LCT control) were first preadministered normal saline plus Intralipid (Otsuka Pharmaceutical Co, Ltd, Tokyo, Japan) as a placebo, whereas group C (LCT study) and group D (MCT/LCT study) received each formulation of propofol 0.1 mg/kg before induction. After three minutes, groups A and C received LCT propofol two mg/kg for induction. Groups B and D received LCT/MCT propofol in the same manner. MEASUREMENT: Pain was evaluated blindly at the time of both preadministration and induction, using a 4-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain. MAIN RESULTS: 36 (72%) LCT and 31 (62%) LCT/MCT control group patients (groups A and B) had pain. Pretreatment with propofol (groups C and D) attenuated the frequency of pain significantly in 21 (42%) and 24 (48%) patients at induction, respectively. CONCLUSION: Long-chain triglyceride and LCT/MCT propofol, 0.1 mg/kg administration before induction, resulted in attenuated pain at an induction dose of propofol.     

Mechanism of injection pain with long and longmedium chain triglyceride emulsive propofol

PURPOSE: t has been suggested that long-medium chain triglyceride (LCT/MCT) emulsive propofol causes less injection pain than long chain triglyceride (LCT) emulsive propofol because of the decreased propofol concentration in the aqueous phase. Alternatively, LCT propofol generates bradykinin causing the injection pain and activates complement, but these effects when using LCT/MCT propofol have not been examined. To identify the mechanism for reduced pain with LCT/MCT propofol, injection pain, bradykinin generation and complement activation with use of both propofol products were compared. METHODS: Two hundred adult patients randomly allocated to two groups were given 1.5 mg x kg(-1) iv of either LCT propofol or LCT/MCT propofol at a rate of 200 mg x min(-1) in a double-blind manner and were asked to grade pain scores. In another study, bradykinin and activated complement 3 (C3a) concentrations were measured using blood obtained from 13 healthy volunteers mixed with saline, LCT propofol or LCT/MCT propofol. RESULTS: There was a significant difference in pain scores between groups, showing a lower incidence of injection pain in the LCT/MCT propofol group. The bradykinin concentrations in blood mixed with LCT and LCT/MCT propofol were significantly higher than in blood mixed with saline. The C3a concentrations showed similar results. CONCLUSIONS: LCT/MCT propofol causes less pain on injection compared with LCT propofol. Bradykinin generation and complement activation are similar with both LCT and LCT/MCT propofol. Thus, the reason for less pain on injection with LCT/MCT propofol may be attributed to a decreased concentration of propofol in the aqueous phase.     

How to decrease pain at rapid injection of propofol: effectiveness of flurbiprofen

Purpose Many studies have been conducted on how to decrease propofol injection pain, but none has been completely successful. In the present study, the most effective method was investigated by adding lidocaine or a nonsteroidal antiinflammatory drug or by changing the solvent. Methods A total of 250 patients scheduled for general anesthesia were divided into five groups. Anesthesia was induced with intravenous administration of flurbiprofen 50 mg followed immediately by propofol in a long-chain triglyceride (LCT) 2 mg·kg⁻¹ (flurbiprofen group, n = 50), flurbiprofen 50 mg followed by propofol LCT 2 mg·kg⁻¹ 1 min later (flurbiprofen 1 group, n = 50), 2% lidocaine 40 mg followed immediately by propofol LCT 2 mg·kg⁻¹ (lidocaine group, n = 50), propofol LCT 2 mg·kg⁻¹ alone (LCT group, n = 50), or propofol in a mixture of medium-chain triglyceride (MCT) and LCT 2 mg·kg⁻¹ (MCT/LCT group, n = 50). Pain at injection was assessed 10 and 20 s after starting the propofol infusion. Results The numbers of patients with severe and mild pain were larger in the order: LCT group (10 and 31 patients, respectively) > flurbiprofen 1 group (3 and 19) ≥ MCT/LCT group (1 and 14) ≥ lidocaine group (2 and 11) > flurbiprofen group (0 and 0). Conclusions Flurbiprofen 50 mg i.v. just before propofol injection completely abolished propofol injection pain. When it was administered 1 min before propofol injection it was less effective.     

Comparative study between propofol in a long-chain triglyceride and propofol in a medium/long-chain triglyceride during sedation with target-controlled infusion

This study was performed to compare the pharmacological characteristics of propofol in an emulsion of both medium- and long-chain triglycerides (MCT/LCT) with those of propofol in an LCT emulsion, by measuring the sedative level and the plasma concentration of propofol during sedation using a target-controlled infusion (TCI) technique. Forty ASA 1 or 2 adult patients who required spinal anaesthesia for surgery were enrolled in this study. The patients were divided into two groups: a propofol LCT group (n = 20) and a propofol MCT/LCT group (n = 20). Propofol was injected intravenously at target blood concentrations of 2.0, 3.0 and 4.0 microg x ml(-1). The bispectral (BIS) index was recorded, and arterial blood was drawn to measure the actual plasma concentrations of propofol at each predicted concentration. Propofol was assayed by high-performance liquid chromatography. Propofol MCT/LCT was associated with significantly less pain than propofol LCT (P < 0.05). There were no significant differences between the two groups in BIS index or in plasma concentration of propofol at each predicted concentration. Computer-generated TCI of propofol MCT/LCT during sedation is comparable with that of propofol LCT with respect to pharmacokinetics and pharmacodynamics. The formulation of MCT/LCT has a beneficial effect with respect to less pain on injection.     

Changes in concentrations of free propofol by modification of the solution

Because free propofol is thought to be responsible for pain on injection, we investigated the changes in concentrations of free propofol by modifying two kinds of propofol products in a medium- and long-chain triglyceride (MCT/LCT) emulsion and in an LCT emulsion. The techniques used in this study were 1) mixing 2% lidocaine (10:1), 2) mixing 5% dextrose in acetated Ringer's solution to reduce pH (10:1), and 3) changing the temperature to 4 degrees , 20 degrees , and 36 degrees C. The propofol preparations were dialyzed for 24 h, and the receptor medium was analyzed using high-performance liquid chromatography. The concentration of free propofol in propofol MCT/LCT was significantly smaller by 30% than that in propofol LCT. Neither mixing lidocaine nor cooling reduced the concentrations of free propofol in both products, but the concentrations were reduced by a decrease in pH and by an increase in temperature. Because mixing lidocaine can induce instability in an emulsion of propofol and warming can rapidly induce microbial growth, injection of lidocaine before propofol administration is recommended to reduce the pain on injection. The concentrations of free propofol in propofol MCT/LCT were significantly smaller (by approximately 30%-45%) than those in propofol LCT during any situation in this study. IMPLICATIONS: Neither mixing lidocaine nor cooling reduced the concentrations of free propofol in both products but the concentrations were reduced by a decrease in pH and by an increase in temperature. Propofol medium- and long-chain triglycerides had significantly smaller concentrations by approximately 30%-45% than those in propofol long-chain triglycerides during any situation in this study.     

The effects of intravenous lidocaine on pain during injection of medium- and long-chain triglyceride propofol emulsions

Propofol formulated in medium- and long-chain triglycerides (MCT/LCT) is thought to cause less pain on injection. In this study we sought to determine if adding lidocaine to propofol-MCT/LCT is more effective in decreasing pain compared with propofol-MCT/LCT alone or conventional propofol-lidocaine mixtures. Seventy-five patients were randomized into three groups. Group A received conventional propofol-lidocaine mixtures with 20 mg lidocaine, group B received propofol-MCT/LCT with saline, and group C received propofol-MCT/LCT with 20 mg lidocaine. The incidence of pain was 24% in groups A and B and 4% in group C. The number needed to treat to prevent pain was 5. We conclude that propofol-MCT/LCT-lidocaine mixtures significantly reduce pain.     

Propofol injection pain in children: a prospective randomized double-blind trial of a new propofol formulation versus propofol with added lidocaine

Background. The incidence of pain on injection of propofol remainsunacceptably high in children, despite various strategies toreduce it. A new drug formulation of propofol has, in adultstudies, been reported to cause less injection pain comparedwith other propofol solutions. The aim of the present prospectiverandomized double-blind clinical trial was to compare the incidenceof pain-free injection following the use of this new formulationwith that following the use of propofol with added lidocainein children undergoing day case surgery. Methods. Eighty-three children (age range 2–18 yr) wererandomized to receive 3 mg kg^–1 of either Propofol-Lipuro®(propofol dissolved in a mixture of medium- and long-chain triglycerides[MCT–LCT]; group pL, n=42) or Diprivan® (propofoldissolved in long-chain triglycerides [LCT]) with added lidocaine(0.3 mg kg^–1) (group pD, n=41). A specially trained nurseanaesthetist assessed the occurrence of injection pain usinga four-graded pain scale. Results. Significantly fewer patients had an entirely pain-freepropofol injection in group pL (33.3%) than in group pD (61.0%)(P=0.016). Conclusions. A new MCT–LCT propofol formulation as a plainsolution was associated with a higher incidence of injectionpain than LCT propofol with added lidocaine when used for inductionof anaesthesia in children.     

Weniger Injektionsschmerz durch Propofol-MCT/LCT? Ein Vergleich mit Propofol-LCT

BACKGROUND: Pain on injection is a major disadvantage of propofol, experienced by the vast majority of patients. Since the traditional formulation has almost normal osmolality and pH, it is hypothesised that the concentration of free propofol in the aqueous phase of the emulsion is responsible for the pain and that reducing the amount of free propofol would also reduce the frequency and intensity of pain on injection. This study was designed to investigate whether pain on injection can be reduced in frequency and intensity by a new formulation of propofol. METHODS: We performed a monocentre, controlled, randomised, double-blind study to compare the pain produced by intravenous injection of a new propofol preparation (propofol-MCT/LCT) with standard propofol in patients undergoing elective surgical procedures. A total of 184 non-premedicated patients received either 1% propofol prepared in a mixture of medium and long chain triglycerides (Propofol-MCT/LCT, Propofol- Lipuro, B. Braum Melsungen AG) or standard 1% propofol prepared exclusively in long chain triglycerides (Propofol-LCT; Disoprivan, AstraZeneca) into a vein of the dorsal hand for induction of anaesthesia. Anaesthesia was maintained by TIVA with propofol and remifentanil. Pain on injection was recorded and graded as none, mild, moderate or severe. RESULTS: Patients receiving propofol-MCT/LCT had a significantly lower incidence of pain on injection compared to the standard propofol group (37% vs 64%) with the intensity of pain also being less severe. There were no differences between both groups in propofol dosage for induction (3.2 +/- 0.8 mg/kg vs 3.3 +/- 0.9 mg/kg) and maintenance of anaesthesia (3.4 +/- 0.6 mg/kg/h vs 3.2 +/- 0.5 mg/kg/h), remifentanil dosage (25 +/- 6 micrograms/kg/h vs. 24 +/- 6 micrograms/kg/h), intraoperative hemodynamics, recovery parameters and postoperative patient satisfaction. Postoperative thrombophlebitis at the injection site for propofol was not observed in any of the patients. CONCLUSIONS: Propofol-MCT/LCT produced significantly less pain on injection when compared to standard propofol in ASA I and II patients undergoing elective surgery. Pain was also significantly less severe, with both effects presumably being due to the lower concentration of free propofol in the MCT/LCT-preparation. With regard to injection pain propofol-MCT/LCT offers significant a advantage over standard propofol.     

不同赋形剂异丙酚对患者肝移植术中血脂及肝功能的影响

目的 探讨不同赋形剂异丙酚对患者肝移植术中血脂及肝功能的影响.方法 择期拟行经典式非转流原位肝移植术患者40例,年龄40～64岁,体重50～75 kg,ASA分级Ⅲ或Ⅳ级,采用随机数字表法,将患者随机分为2组(n=20):异丙酚中/长链甘油三酯注射液组(M组)和异丙酚长链甘油三酯注射液组(L组).麻醉诱导:静脉注射盐酸戊乙奎醚1 mg、眯达唑仑0.04～0.06 mg/kg,舒芬太尼0.6～0.8μg/kg和维库溴铵0.10～0.15mg/kg,M组和L组分别静脉注射不同赋形剂的异丙酚1.5～2.0 mg/kg,气管插管后行机械通气.麻醉维持:吸入1%～2%异氟醚、M组和L组分别静脉输注不同赋形剂的异丙酚3～4 mg·kg-1·h-1和顺阿曲库铵0.2～0.3 mg·kg-1·h-1,间断静脉注射舒芬太尼0.2～0.3μg/kg.于入室(T1)、切皮前(T2)、无肝前期末(T3)、无肝期末(T4)、新肝期30 min(T5)、240 min(T6)时采集静脉血样,测定血浆甘油三酯(TG)、总胆固醇(CH)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)浓度及AST、ALT活性,并计算各指标的相对基线变化值.结果 与L组比较,M组T4-6时△TG降低(P＜0.05),△CH、△HDL-C、LDL-C、△AST、△ALT差异无统计学意义(P＞0.05).两组间血浆TG、CH、HDL-C、LDL-C浓度、AST和ALT活性比较差异无统计学意义(P＞0.05).结论 异丙酚中/长链甘油三酯注射液和异丙酚长链甘油三酯注射液虽然对肝功能影响无差异,但异丙酚中/长链甘油三酯注射液对血脂影响小,更有益于肝移植术患者.

Abstract：

Objective To investigate the effect of different excipients of propofol on blood lipids and liver function during orthotopic liver transplantation. Methods Forty ASA Ⅲ- Ⅳ patients aged 40-64 yr weighing 50-75 kg undergoing orthotopic liver transplantation were randomly divided into 2 groups ( n = 20 each): propofol medium-chain triglycerides/long-chain triglycerides (MCT/LCT) group (group M) and propofol LCT group (group L). Anesthesia was induced with penehyclidine 1 mg, midazolam 0.04-0.06 mg/kg, sufentanil 0.6-0.8 μg/kg and propofol 1.5-2.0 mg/kg. Tracheal intubation was facilitated with vecuronium 0.10-0.15 mg/kg. The patients were mechanically ventilated. Anesthesia was maintained with 1%-2% isoflurane, continuous infusion of propofol blood samples were collected after admission into the operation room (T1), before skin incision (T2), at the end of pre-anhepatic phase (T3), at the end of anhepatic phase (T4) and 30 and 240 min of neohepatic phase (T5, T6 )for determination of plasma concentrations of triglyceride (TG), total cholesterol (CH), high-density-lipoproteincholesterol (HDL-C), low density-lipoprotein-cholesterol (LDL-C), and activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The changes in parameters from baseline values were calculated. Results Compared with group L, △TG was significant1y decreased at T4-6 in group M ( P ＜ 0.05 ) . There was no significant difference in △CH, △HDL-C, △LDL-C, △AST and △ALT,plasma concentrations of TG,CH, HDL-C and LDL-C,and activities of AST and ALT between the two groups ( P ＞ 0.05). Conclusion The effect of the two formulations of propofol on liver function is comparable. Propofol MCT/LCT exerts less effect on blood lipids during liver transplantation and is more suitable for this type of surgery.     

Tourniquet at 50 mm Hg followed by intravenous lidocaine diminishes hand pain associated with propofol injection.

We evaluated the efficacy of intravenous lidocaine, with and without a tourniquet, to decrease the intensity of pain during intravenous propofol injection in 82 patients undergoing general anesthesia. Patients in group A (n = 20) received propofol (2 mg/kg IV); patients in group B (n = 22) received 2% lidocaine (100 mg IV) followed 1 min later by propofol (2 mg/kg). Patients in group C (n = 21, saline placebo) and D (n = 19, 2% lidocaine) had an arm tourniquet inflated to 50 mm Hg applied for 1 min after gravity drainage of venous blood. The intensity of pain along the forearm was marked on a 0-100-mm visual analogue scale. Pain intensity was less in group B (21 +/- 19 mm) than in group A (75 +/- 28 mm; P less than 0.05). Pain intensity was significantly less in group D (1 +/- 2 mm) compared with group B (21 +/- 19 mm; P less than 0.001). We conclude that intravenous lidocaine before propofol injection attenuates the painful response; whereas, lidocaine administered after a tourniquet inflated to 50 mm Hg for 1 min virtually abolishes the pain associated with intravenous propofol.     

Does the newer preparation of propofol,an emulsion of medium/long chain triglycerides cause less injection pain in children when premixed with lignocaine?

Background: Injection pain during propofol administration can be particularly distressing in children. The newly available emulsion of propofol in medium and long chain triglycerides (LCT) is reported to cause less injection pain because of lower concentrations of free propofol. This study compared the incidence of injection pain during administration of propofol emulsion of LCT and propofol emulsion of medium and long chain triglycerides (MCT/LCT) both premixed with lignocaine in children. Methods: This prospective, randomized, double blind study was conducted after obtaining institutional ethics committee approval, parental consent and included 84 children aged 5–15 years. Preoperatively, an intravenous cannula was inserted in all children. four children were excluded. Those included, depending on the randomization, received 3 mg·kg^?1 of either propofol LCT or propofol MCT/LCT both premixed with lignocaine (0.1%). The incidence and intensity of injection pain was assessed. Results: Pain on injection of propofol LCT with lignocaine was observed in 16/40 children (40%), five of these children complained of severe pain. In comparison, 14/40 (35%) children complained of pain following propofol MCT/LCT premixed with lignocaine (P = 0.644), the intensity being severe in two children (P = 0.698). Conclusions: Propofol MCT/LCT and propofol LCT premixed with lignocaine are both associated with pain on injection in children; the incidence and intensity of the injection pain are similar.     

Propofol formulated with long-/medium-chain triglycerides reduces the pain of injection by target controlled infusion

BACKGROUND: Propofol is a widely used intravenous anesthetic although its injection pain is a common and unpleasant problem. Long-/medium-chain triglyceride (LCT/MCT) propofol has been introduced, as its low free propofol content is expected to reduce injection pain compared with LCT propofol. Target controlled infusion (TCI) differs from conventional induction in the initial infusion pattern. During induction using TCI, we investigated injection pain caused by two propofol solutions with different triglyceride compositions. METHODS: Fifty patients, ASA I-II, with adequate communicative ability, were randomly assigned to two groups. TCI was conducted with Diprifusor for LCT and with BeComSim (custom-made software) for LCT/MCT. The target blood concentration was set at 4 microg/ml for both groups. At 30, 60, and 120 s after the infusion, patients were asked questions regarding the severity of pain on a 0-10 pain score. The total dose of propofol and the time required to induce anesthesia were also investigated. RESULTS: The LCT/MCT propofol group had a larger number of pain-free patients and showed lower severity of pain than the LCT group [the number of pain-free patients being 11 and 3, respectively (P < 0.05), and median maximum pain being 0 and 4.5, respectively (P < 0.01)]. The dose and time required for induction were not significantly different between the groups (dose of 84 +/- 27 and 80 +/- 24 mg, respectively, and time of 119 +/- 60 and 107 +/- 55 s, respectively). CONCLUSION: Our study showed that the frequency and severity of pain during TCI induction with propofol could be significantly reduced using LCT/MCT propofol rather than LCT propofol.     

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.     

The effect of mixing lidocaine with propofol on the dose of propofol required for induction of anesthesia

Lidocaine is used to reduce pain associated with propofol injection, either mixed with propofol or preceding it as a separate injection. The addition of lidocaine to propofol causes destabilization of the emulsion and reduces anesthetic potency in rats and humans. We conducted a randomized double-blinded study on 67 patients to assess the effect of mixing lidocaine with propofol on the dose of propofol required for the induction of anesthesia. Patients in Group S (n = 32) received IV lidocaine 0.2 mg/kg followed by an infusion of propofol whereas those in Group M (n = 35) received IV normal saline (placebo) followed by an infusion of a freshly prepared mixture of propofol 1%/lidocaine 1% in 10:1 volume ratio. The infusion was stopped when the subjects lost consciousness, as detected by the syringe-drop method. There was no statistically significant difference between the two groups in the mean (95% confidence interval) doses of propofol required for loss of consciousness: 2.0 (1.8-2.2) mg/kg for Group S versus 1.9 (1.7-2.0) mg/kg for Group M (P = 0.206). Mixing 20 mg of lidocaine with 200 mg of propofol is unlikely to affect the dose of propofol required for the induction of anesthesia. IMPLICATIONS: Adding lidocaine to propofol destabilizes the propofol emulsion. A randomized double-blinded trial found no statistically significant difference in the doses of propofol required for the induction of anesthesia whether administered as a freshly prepared propofol 1%/lidocaine 1% 10:1 mixture or as a separate injection after a dose of lidocaine.     

Propofol anesthesia in spontaneously breathing children undergoing magnetic resonance imaging: comparison of two propofol emulsions

BACKGROUND: This study evaluated a propofol-based anesthesia regimen with spontaneous breathing in pediatric patients scheduled for magnetic resonance imaging (MRI). METHODS: In this prospective, randomized, double-blind study propofol formulated with long-chain triglycerides (LCT) and mixed medium-chain/long-chain triglycerides (MCT/LCT) were used. Ninety patients aged 2.4 months to 7.3 years were premedicated with intravenous midazolam. Lidocaine was injected prior to propofol to reduce injection pain. Anesthesia was induced and maintained by propofol. Glycopyrronium bromide was administered for saliva reduction. Hemodynamics, blood oxygen saturation and endtidal capnography were continuously monitored. All patients received additional oxygen. The aggregated propofol dose for induction and maintenance of anesthesia was analyzed for therapeutic equivalence. Incidence of injection pain, laboratory safety values, vital signs, and the adverse event profile were analyzed to compare tolerability and safety. RESULTS: Propofol anesthesia was safe and successful in all children. Both propofol formulations were equivalent regarding dose requirements (mean induction and maintenance doses for anesthesia 2.0-4.0 mg.kg(-1) and 6.0-8.8 mg.kg(-1).h(-1) respectively; aggregated doses 8-13.26 mg.kg(-1)). There were no differences in drug safety such as hemodynamics, spontaneous breathing, injection pain, and laboratory values. Duration of induction and of recovery from anesthesia were short and all examinations were completed with minimal interruption. CONCLUSIONS: Propofol-based short-term anesthesia was well suited for anesthesia during MRI procedures in the studied pediatric patients. There were no clinically relevant differences between the two propofol formulations.     

Comparison of diphenhydramine and lidocaine for prevention of pain after injection of propofol: a double-blind, placebo-controlled, randomized study

BACKGROUND AND OBJECTIVE: Pain on injection is still a problem with propofol. The purpose of the study was to compare the effectiveness of diphenhydramine and lidocaine on pain caused by propofol at the site of injection. METHODS: One hundred and eighty ASA I-II adults undergoing elective surgery were randomly assigned into three groups of 60 each. Group I (placebo) received 2 mL normal saline, Group II received 2 mL (40 mg) 2% lidocaine and Group III received 2 mL (20 mg) diphenhydramine intravenously (i.v.) during a 1-min venous occlusion, followed by propofol into a cephalic forearm vein of the antecubital fossa. Pain assessment was made immediately after propofol injection. RESULTS: In the placebo group 25 (41.7%) patients experienced pain during propofol injection as compared to 2 (3.3%) and 3 (5.0%) in the lidocaine and diphenhydramine groups, respectively. The prevalence of pain and pain score were significantly less in both the lidocaine and diphenhydramine groups than in the placebo group (P = 0.00). No difference was found between the diphenhydramine and lidocaine groups (P = 0.60). CONCLUSION: Previous injection of diphenhydramine with venous occlusion can be considered as an alternative to lidocaine for reducing the prevalence of pain caused by injection of propofol into peripheral veins.     

Propofol in a medium- and long-chain triglyceride emulsion: pharmacological characteristics and potential beneficial effects

Hypertriglyceridemia is a possible unwanted effect during long-term propofol sedation while using a formulation containing long-chain triglycerides (LCT) from soybean oil. The use of propofol formulated in a solvent consisting of medium-chain triglycerides (MCT) and LCT might reduce the risk. Because a new solvent may affect the pharmacological profile of propofol, in this prospective, randomized, controlled, and double-blinded study we compared the pharmacodynamic and kinetic characteristics of propofol diluted in MCT/LCT fat solution with those of propofol formulated in LCT fat emulsion. In addition, serum triglyceride levels were measured during and after the administration of both drugs. Thirty patients likely to require mechanical ventilation over at least 48 h were randomized to receive either propofol 2% MCT/LCT (Group 1) or propofol 2% LCT (Group 2). Infusion rates of propofol (2.34 +/- 0.83 mg. kg(-1). h(-1) in Group 1 versus 2.31 +/- 0.6 mg. kg(-1). h(-1) in Group 2), the plasma propofol concentrations during infusion (0.95 +/- 0.53 versus 0.98 +/- 0.32 micro g/mL), and the concentrations and arousal behavior after discontinuation of the drug did not show significant differences. Plasma triglyceride concentrations during sedation did not differ between the groups, whereas there was a tendency toward a more rapid triglyceride elimination in Group 1 after termination of the propofol administration. IMPLICATIONS: Propofol diluted in an emulsion of medium- and long chain-triglycerides shows equivalent pharmacological properties during long-term sedation compared with its hitherto well known formulation containing long-chain triglycerides only. In addition, potential favorable effects on the plasma triglyceride profile could be found.