Comparison of propofol and thiopentone for induction of anaesthesia in premedicated patients

Thirty premedicated ASA I or II patients scheduled for minor gynaecological surgery, were randomly allocated to receive either 1.5 mg/kg or 2 mg/kg propofol of the new emulsion formulation, or 4 mg/kg thiopentone, given over 20 seconds. Anaesthesia was successfully induced in all 30 patients. The mean (SEM) induction times were for propofol 1.5 mg/kg 33.3(3.2) seconds, for 2 mg/kg 30.5(2.7) seconds and for thiopentone 34.6(2.7) seconds. The incidence of apnoea greater than 10 seconds, was respectively 60, 80 and 80%, and the mean duration of apnoea 30.8(5.3), 37.1(5.0) and 23.7(5.0) seconds. The mean systolic blood pressure decreased after propofol 1.5 mg/kg by 16.0 mmHg, after 2 mg/kg by 18.6 mmHg, and increased after thiopentone by 1 mmHg, 2 minutes after injection. Heart rate increased significantly 2 minutes after thiopentone by an average of 15.1 beats/minute, but not after propofol. Pain was not reported during or after the injection. No major adverse reactions occurred at induction or during maintenance of anaesthesia with an inhalation agent. One patient who received 2 mg/kg propofol and isoflurane vomited for 24 hours. The recovery of anaesthesia after propofol induction, was quicker than after thiopentone.     

Etomidate in electroconvulsive therapy

In a group of 31 patients undergoing electroconvulsive therapy, there was no significant difference between the times of return of eyelash reflex, swallowing and respiration following a single induction dose of 0.2 mg/kg of etomidate as compared with an induction dose of 0.036 ml/kg of alphaxalone/alphadalone. The incidence of involuntary movements and increased muscle tone was significantly greater after etomidate than following alphaxalone/alphadalone; but the involuntary movements were never marked. The overall incidence of pain on injection was 15% after etomidate. There was a low incidence of venous sequelae following either drug.     

Comparative study of propofol with thiopental and etomidate in anesthetic induction]

Anesthetic characteristics were studied in three homogeneous groups of twenty patients ASA I who underwent intravenous anesthetic induction with propofol 2 mg/kg; thiopental 5 mg/kg; or etomidate 0.3 mg/kg. The unconsciousness time was similar in the three groups, whereas awaking time and time of response and orientation were longer after thiopental and etomidate than after propofol. Intravenous injection of the three anesthetic agents was followed by a decrease in systolic and diastolic arterial pressure. Heart rate increased after thiopental and etomidate and had only slight fluctuations after propofol. After tracheal intubation there was a significant increase in systolic and diastolic arterial pressure and heart rate in thiopental and etomidate group. These changes were minimal after propofol. The highest number of complications occurred after etomidate.     

Direct effect of anesthetic inducers on the electromyographic signals of the adductor pollicis

OBJECTIVES: To analyze the effect of thiopental, propofol, etomidate and midazolam on electromyographic study of the adductor pollicis before muscle relaxation. PATIENTS AND METHOD: Prospective study of 96 adults ASA I-II patients (gynecologic surgery) by electromyographic (Reflexograph Datex) recording of the adductor pollicis every 20 seconds with train-of-four (TOF) stimuli. After giving informed consent, the patients were randomized for type of induction agent. We studied changes in T1 (amplitude of the first response to TOF) and the TOF-ratio (T4/T1). The induction agent (thiopental 5 mg/kg), propofol 3 mg/kg, midazolam 0.2 mg/kg or etomidate 0.3 mg/kg) was given by slow 30 s injection 100 s after calibration of the Relaxograph. Changes in T1 and the TOF-ratio were recorded until 240 s. RESULTS: The groups were statistically homogeneous. In the thiopental group, T1 readings at 20, 40, 60 and 80 s (control times) were statistically different from the readings at 180, 220 and 240 s (after administering thiopental). T1 was significantly different at 120 and 200 s in the etomidate group. CONCLUSIONS: Thiopental and etomidate induce slight muscle relaxation at the expense of a reduction in T1 without changing the TOF-ratio, an effect that might be useful for rapid induction. Propofol and midazolam do not affect the electromyogram of the adductor pollicis. Thus, propofol is the anesthetic induction agent of choice for clinical studies on non-depolarizing muscle relaxants given that it changes neither T1 nor the TOF-ratio.     

Does lidocaine more effectively prevent pain upon induction with propofol or etomidate when given preemptively than when mixed with the drug?

Study ObjectiveTo compare the efficacy of 2% lidocaine “timing” on alleviation of pain upon induction using propofol or etomidate.DesignProspective, randomized, double-blinded study.SettingAcademic teaching hospital.Patients80 adult, ASA physical status I, II, and III patients scheduled for elective outpatient or inpatient surgery with an intravenous induction agent.InterventionsPatients were randomly assigned to two groups. Group A received preemptive saline 4 mL and lidocaine 4 mL mixed with either propofol 20 mL (n = 20) or etomidate 20 mL (n = 20). Group B received preemptive lidocaine 4 mL and saline 4 mL mixed with either propofol 20 mL (n = 20) or etomidate 20 mL (n = 20). The 4 mL dose of preemptive drug dwelled for three minutes.MeasurementsThe induction drug mixture was injected over 60 seconds while the patient was assessed for pain using a 4-point scale (0 = no pain,1 = mild, 2 = moderate, and 3 = severe).Main ResultsMean induction pain scores were 1.0 (SD = 0.89) for propofol and 0.9 (SD = 0.90) for etomidate, representing mild induction pain. Mean induction pain scores were 0.93 (SD = 0.92) for the simultaneous treatment groups and 0.98 (SD = 0.87) for the preemptive treatment groups. The observed differences in pain scores between the techniques were not statistically (P > 0.62) or clinically meaningful.ConclusionsAlleviation and intensity of post-injection pain were not significantly influenced by the “timing” of administration of lidocaine 80 mg or by the specific induction drug. Pre-lidocaine and “simultaneous” lidocaine with either propofol or etomidate prevented severe pain in 95% of patients.     

异丙酚复合芬太尼对患者拇短展肌运动诱发电位的影响

目的 探讨异丙酚复合芬太尼对患者拇短展肌运动诱发电位(MEP)的影响.方法 择期普通外科手术患者11例,ASA Ⅰ或Ⅱ级,年龄26～48岁.以第6颈椎棘突为刺激线圈的中点进行磁刺激,周期20s.试验Ⅰ:经30 s匀速静脉注射异丙酚2mg/kg.记录给药即刻至患者出现睁眼或体动反应期间右拇短展肌MEP波幅的基础值、最低值和最后值,及其对应的潜伏期,以及波幅下降至最低值的时间(时程).试验Ⅱ:试验Ⅰ结束后30 min,经大隐静脉依次匀速注射异丙酚2 mg/kg和芬太尼5 μg/kg,每种药物注射时间为30 s.记录给药即刻开始拇短展肌MEP波幅的基础值、最低值和最后值,及其对应的潜伏期,以及时程,记录时间为360 s.结果 与基础值比较,两试验拇短展肌MEP波幅的最低值和最后值降低(P<0.01);与试验Ⅰ比较,试验Ⅱ拇短展肌MEP波幅的最后值降低(P<0.05).结论 与静脉注射异丙酚比较,异丙酚复合芬太尼对患者拇短展肌MEP的抑制作用更强.     

Awareness during laryngoscopy and intubation: quantitating incidence following induction of balanced anesthesia with etomidate and cisatracurium as detected with the isolated forearm technique

STUDY OBJECTIVE: To measure the incidence of awareness during induction of anesthesia with etomidate and fentanyl, and to model its frequency as a function of dose of etomidate. DESIGN: Prospective cohort study.Setting: Anesthesia department of a university hospital. PATIENTS: 30 ASA physical status I, II, and III patients undergoing elective general surgery. INTERVENTIONS: Patients were assigned to one of three groups of etomidate (0.2 mg/kg, 0.3 mg/kg, 0.4 mg/kg) and received fentanyl (2 microg/kg) and 2 x ED(95) of cisatracurium (0.1 mg/kg). Neuromuscular block was monitored with a peripheral nerve stimulator. Intubation was performed after maximum T(1)-depression. To identify awareness, the isolated forearm technique (IFT) was used. The IFT was performed by prompting the patient every 20 seconds. Only a verified response was considered a positive IFT response. Anesthesia was maintained with isoflurane in oxygen/air and fentanyl. MEASUREMENTS AND MAIN RESULTS: Maximum neuromuscular block occurred after 352 +/- 96 seconds and intubation was performed 424 +/- 86 seconds after loss of consciousness (LOC). Awareness was dose dependent: 80% of patients receiving 0.2 mg/kg etomidate, 70% of patients receiving 0.3 mg/kg etomidate, and 20% of patients receiving 0.4 mg/kg etomidate had a positive IFT response. Awareness occurred in one patient 3 minutes after LOC, in 65% during laryngoscopy, and in 30% within the following 120 seconds. One patient had explicit recall without finding awareness unpleasant. Hemodynamic parameters did not differ between patients with a positive or a negative IFT response. CONCLUSIONS: The incidence of awareness during bolus induction can be modeled as dose dependent. However, when combining a short-acting induction drug and a delayed-onset neuromuscular blocker, the continuous infusion of the hypnotic drug may prevent awareness during induction.     

Sensitivity to propofol in the elderly

Two studies were carried out on 609 fit, unpremedicated patients to assess the influence of patient age on the response to the rapidly-acting hindered phenol, propofol, which is being evaluated for induction of anaesthesia. In the first study, 1.25 mg/kg was injected over 20 seconds followed by 10-mg increments every 15 seconds until loss of verbal contact. This showed a great individual variation in response to the drug. A reduction in the 'induction' dose was found in elderly patients, which became marked around 60 years. In the second (340), doses ranging from 1.5-3.0 mg/kg in patients under 60 years and 1.25-2.25 mg/kg in those over 60 years were injected as a bolus over 20 seconds. Doses of 2.25-2.5 mg/kg were required to induce anaesthesia in patients under 60 years, whilst 1.5-1.75 mg/kg was adequate in those over 60 years. Side effects were more marked with the rapid injection and doses in excess of 1.75 mg/kg caused significant hypotension and apnoea in the elderly. These studies reveal marked sensitivity to propofol in the elderly with respect to both induction dose and acute toxicity.     

胃镜检查术患者乳化依托咪酯-芬太尼咪达唑仑麻醉的效果

目的 评价胃镜检查术患者乳化依托咪酯.芬太尼-咪达唑仑麻醉的效果.方法 拟行胃镜检查术患者400例,年龄18～60岁,体重40～80 ks,ASA Ⅰ或Ⅱ级,随机分为4组:异丙酚复合芬太尼组(PF组)、乳化依托咪酯复合芬太尼组(EF组)、异丙酚-芬太尼-咪达唑仑组(PFM组)及乳化依托咪酯-芬太尼-咪达唑仑组(EFM组),每组100例.采用双盲法给药.静脉注射芬太尼或芬太尼-咪达唑仑0.1 ml/kg,随后静脉注射异丙酚或乳化依托咪酯1 ml/6 s,待患者睫毛反射消失后停止注射,行胃镜检查术,术中根据患者情况追加少量乳化依托咪酯或异丙酚,保留自主呼吸,面罩吸氧.记录麻醉诱导时间、胃镜检查时间、乳化依托咪酯用量、异丙酚用量、阿托品和麻黄碱使用情况、内镜医师和麻醉科医师对麻醉效果的满意程度及术后苏醒时间;记录术中体动、呼吸暂停、低氧血症、心动过缓、低血压、肌阵挛及术后有关并发症的发生情况.结果 与PF组和PFM组比较,EF组和EFM组苏醒时间延长,术中低氧血症、呼吸暂停、低血压及注射痛的发生率降低,术中最低血压值升高,麻黄碱使用率降低,术中肌阵挛发生率、术后恶心、呕吐及头晕的发生率及麻醉科医师满意程度升高(P＜0.05);与EF组比较,EFM组术中肌阵挛及术后恶心、呕吐、头晕的发生率降低,低血压发生率升高(P＜0.05).结论 乳化依托咪酯-芬太尼-咪达唑仑对胃镜检查术患者循环和呼吸功能的抑制程度较轻,术中及术后有关并发症发生率低.     

Effects of speed of injection on anesthesia induction with propofol and fentanyl]

We examined the effects of injection rate of propofol on injection pain and postinduction hypotension and bradycardia when fentanyl was administrated before propofol. Fifty-five patients premedicated with midazolam and atropine were randomly allocated to two groups. Three minutes after administration of fentanyl 100 micrograms, propofol 1.5 mg.kg-1 was injected to a forearm vein at a rate of 800 ml.hr-1 in Group FS or 1 ml.s-1 in Group FR. Anesthesia was maintained with 67% nitrous oxide in oxygen and supplemental propofol infusion. The incidence and severity of pain on injection were not influenced with injection speed. The rapid rate of injection significantly shortened the induction time. The decrease in systolic and diastolic blood pressures and heart rate after induction were not affected by injection speed. In conclusion, rapid injection of propofol after fentanyl was effective to shorten the induction time without increasing the postinduction hypotension and bradycardia.     

依托咪酯和丙泊酚单一制剂在胃镜操作全麻方案的比较研究

目的 比较依托咪酯和丙泊酚单一制剂在全麻胃镜操作中的应用特点.方法 择期行胃镜检查术100例,用随机数字表法随机分为依托咪酯(E)组和丙泊酚(P)组,双盲法给药.E组静注依托咪酯0.3 mg/kg,术中胃镜置入时追加0.1 mg/kg.P组静注丙泊酚2.5 mg/kg,术中胃镜置入时追加1 mg/kg.Ramsay分级...     

Comparison of the Effects of Etomidate, Propofol, and Thiopental on Respiratory Resistance after Tracheal Intubation

Background: Tracheal intubation frequently results in reversible bronchoconstriction. Propofol has been reported to minimize this response in healthy patients and in asthma patients, but may be unsuitable for hemodynamically unstable patients for whom etomidate may be preferable. The current study examined respiratory resistance after tracheal intubation after induction with either thiopental, etomidate, or propofol. A supratherapeutic dose of etomidate was used to test the hypothesis that the bronchoconstrictive response could be minimized by deep intravenous anesthesia.

Methods: Seventy-seven studies were conducted in 75 patients. Anesthesia was induced with either 2.5 mg/kg propofol, 0.4 mg/kg etomidate, or 5 mg/kg thiopental. Respiratory resistance was measured at 2 min after induction.

Results: Respiratory resistance at 2 min was 8.1+/-3.4 cmH sub 2 O *symbol* l sup -1 *symbol* s (mean+/-SD) for patients receiving propofol versus 11.3+/-5.3 for patients receiving etomidate and 12.3+/-7.9 for patients receiving thiopental (P less than or equal to 0.05 for propofol vs. either etomidate or thiopental).     

Does the choice of intravenous induction drug affect intubation conditions after a fast-onset neuromuscular blocker?

STUDY OBJECTIVES: To compare intubation conditions and hemodynamic effects resulting from thiopental-rapacuronium, propofol-rapacuronium, and etomidate-rapacuronium intravenous (IV) induction. DESIGN: Randomized, blinded study. SETTING: Operating suites of a large university-affiliated medical center. PATIENTS: 60 ASA physical status I and II adult patients without airway abnormalities, who were scheduled for elective surgery requiring endotracheal intubation.Patients were randomly allocated to receive IV thiopental sodium 5 mg/kg (Group 1), propofol 2 mg/kg (Group 2), or etomidate 0.3 mg/kg (Group 3) followed by rapacuronium 1.5 mg/kg. Fifty seconds later, an anesthesiologist, who had no knowledge of the induction drug used, entered the operating room and attempted laryngoscopy and intubation. MEASUREMENTS: Intubation conditions were graded as excellent, good, poor, or impossible according to Good Clinical Research Practice criteria. Arterial blood pressure and heart rate changes accompanying both induction techniques were also monitored and recorded. MAIN RESULTS: All patients were intubated within 55 to 70 seconds. Clinically acceptable intubation conditions were not statistically different among the three groups. Moderate tachycardia after induction was seen in all three groups, and blood pressure was significantly lower in Group 2 than in Groups 1 or 3. CONCLUSIONS: Clinically acceptable intubation conditions are similar after either thiopental, propofol, or etomidate when a fast-onset neuromuscular blocking drug (rapacuronium 1.5 mg/kg) is used to facilitate tracheal intubation.     

异丙酚与依托咪酯复合硬膜外阻滞对血糖和皮质醇的影响

目的和方法：１２０例ＡＳＡⅠ～Ⅱ级成年病人,按照全麻诱导和维持用药随机分成依托咪酯（Ｅ组,ｎ＝６０）和异丙酚（Ｐ组,ｎ＝６０）两组。两组病人均硬膜外穿刺置管,Ｅ组病人诱导用依托咪酯０２５ｍｇ／ｋｇ,维持时负荷剂量为２０μｇ·ｋｇ－１·ｍｉｎ－１,维持剂量为６μｇ·ｋｇ－１·ｍｉｎ－１;Ｐ组病人诱导用异丙酚１５ｍｇ／ｋｇ,维持时负荷剂量为１６０μｇ·ｋｇ－１·ｍｉｎ－１,维持剂量为５０μｇ·ｋｇ－１·ｍｉｎ－１。观察术中心血管反应、血浆皮质醇和血糖的变化。结果：异丙酚和依托咪酯静脉诱导后均可造成血压下降,异丙酚较为严重,但术中两组病人的血压脉率皆容易维持稳定。两组病人术中血糖随着手术进程缓慢升高,Ｐ组病人血浆皮质醇变化与血糖相似,而Ｅ组病人术中血浆皮质醇水平缓慢降低,直至术后２４小时方恢复。结论：在硬膜外阻滞复合异丙酚静脉全麻时,尽管手术创伤所致的心血管应激反应已经控制,但体内应激激素依然保持适度增高。而依托咪酯则抑制肾上腺皮质,致血浆皮质醇水平下降,不适合用作长期静脉麻醉的维持。     

依托咪酯-丙泊酚镇静在门诊结肠镜检查中的应用

目的比较单独或联合使用依托咪酯和丙泊酚的不同镇静方案在无痛结肠镜检查中的安全性和不良反应。方法选择拟行无痛结肠镜检查患者280例,男128例,女152例,年龄18~65岁,体重45~70kg,ASAⅠ~Ⅲ级,随机分为四组,每组70例。P组采用丙泊酚1mg/kg诱导后,每次给予丙泊酚0.5 mg/kg维持;EP组采用依托咪酯0.2 mg/kg诱导后每次给予丙泊酚0.5mg/kg维持;PE组采用丙泊酚1mg/kg诱导后每次给予依托咪酯0.1mg/kg维持;E组采用依托咪酯0.2mg/kg诱导后每次给予依托咪酯0.1 mg/kg维持。记录四组患者镇静前后的MAP、HR、SpO2;记录患者诱导和恢复时间以及不良反应发生情况。结果 EP组(16.7±10.1)mm Hg和E组(14.5±8.7)mm Hg的ΔMAP的下降值明显小于P组(26.2±10.1)mm Hg和PE组(24.4±9.4)mm Hg(P0.05)。EP组(61.3±19.5)s和E组(60.1±20.3)s的诱导时间明显短于P组(70.3±25.9)s和PE组(72.2±29.8)s(P0.05)。EP组(11.42%)和E组(1.85%)的低血压发生率明显低于P组(51.42%)和PE组(37.14%)(P0.05)。E组(4.28%)上呼吸道梗阻发生率明显低于其它三组(P0.05)。E组肌颤发生率(41.42%)明显高于其它三组,EP组肌颤发生率(20%)明显高于P组(0%)和PE组(5.71%)(P0.05)。只有E组发生术后恶心呕吐。结论依托咪酯诱导、丙泊酚维持镇静对血流动力学影响较小,能快速诱导;与单独应用依托咪酯比较,肌颤、恶心呕吐的发生率更低。     

Induction characteristics of propofol in children: comparison with thiopentone

The induction characteristics of propofol were studied and compared with thiopentone in children aged 3-14 years who received either no premedication or pethidine-atropine or trimeprazine. Anaesthesia was maintained with nitrous oxide in oxygen, and isoflurane. The induction doses of propofol and thiopentone were 2.9 mg/kg and 6.5-7.1 mg/kg respectively; premedication had no significant effect on the induction doses of either agent. Spontaneous movement and hypertonus occurred in about 20% of children with both agents. The use of propofol was associated with a high incidence of pain on injection (injections were mostly in veins on the dorsum of the hand), but this was reduced by mixing lignocaine with propofol. Cardiovascular effects were not clinically significant with either agent. Apnoea occurred in 35% of patients given propofol and in 50% of those given thiopentone. Children anaesthetised with propofol awoke significantly earlier after cessation of all anaesthesia. It is concluded that the use of propofol is safe in children and may have advantages where early recovery from anaesthesia is desirable, but offers no advantage over thiopentone for routine induction of anaesthesia.     

Comparison of the effects of remifentanil or fentanyl on anaesthetic induction characteristics of propofol,thiopental or etomidate

BACKGROUND AND OBJECTIVE: This prospective, randomized, double-blinded study was designed to compare the effects of remifentanil or fentanyl on anaesthetic induction characteristics of propofol, thiopental or etomidate. METHODS: Seventy-two patients were enrolled in six groups of 12 individuals each. In three groups, fentanyl was given as a bolus dose of 1.5 microg kg(-1), whereas the others received a remifentanil infusion at 0.5 microg kg(-1) min(-1). Five minutes later, propofol, thiopental or etomidate were titrated to a state of unresponsiveness. Assessment included the amounts of drug necessary for induction, haemodynamics and the times to apnoea, loss of eyelash reflex, and the release of a water-filled syringe held in the patient's hand. RESULTS: Induction times to loss of the eyelash reflex were significantly shorter in the remifentanil than in the fentanyl groups: with propofol 50.7 +/- 13.6s (mean +/- SD) versus 74.9 +/- 27.0s (P < 0.01), with thiopental 42.9 +/- 16.8s versus 77.2 +/- 27.8s (P < 0.01) and with etomidate 54.7 +/- 17.6s versus 72.3 +/- 24.0s (P < 0.05). The times to respiratory arrest or for the syringe to fall were significantly shorter with remifentanil than with fentanyl for propofol and for thiopental, but not for etomidate. In terms of dosages per kg body weight necessary to achieve unresponsiveness, less propofol (-29%, P < 0.05), thiopental (-25%, P < 0.05) or etomidate (-32%, P < 0.01) was necessary with remifentanil than with fentanyl. Haemodynamic responses to tracheal intubation were controlled more effectively with remifentanil. However, within the remifentanil groups, mean arterial pressure significantly decreased during induction: -26% with propofol, -181% with thiopental and -14% with etomidate (all P < 0.01). CONCLUSIONS: During anaesthetic induction, a remifentanil infusion of 0.5 microg kg(-1) min(-1) over 5 min is a suitable alternative to a 1.5 microg kg(-1) bolus dose of fentanyl: induction times are shorter with reduced amounts of propofol, thiopental or etomidate.     

Comparision of etomidate and propofol for fibreoptic intubation as part of an airway management algorithm:a prospective, randomizes, double-blind study

BACKGROUND AND OBJECTIVE: In our algorithm for management of the anticipated difficult airway the induction agent (etomidate) is administered after the tip of the fibreoptic is placed in the trachea but before the tube is advanced over it. In a previous investigation we demonstrated the safety of this method. Due to its popularity as an induction agent, some would like to replace etomidate with propofol. However, because rapid recovery of spontaneous breathing is crucial with this technique, substitution might not be advisable. We compared the speed of recovery of spontaneous breathing after fibreoptic intubation between etomidate and propofol. METHODS: In this prospective, randomized, double-blind study we used either 0.2 mg kg[-1] etomidate or 2 mg kg[-1] propofol for induction. Our technique of nasotracheal fibreoptic intubation consists of using fentanyl, cocaine instillation into the lower nasal canals, cricothyroid injection of lidocaine, performing bronchoscopy, administration of etomidate and advancing the tube after loss of consciousness. We measured time to loss of consciousness, time to recovery of spontaneous breathing, lowest bi-spectral index value and time to lowest value. RESULTS: Time to loss of consciousness did not differ. The time to recovery of spontaneous breathing differed significantly: the median time (interquartile range [range]) for etomidate was 81 s (62--102 [0--166]), and for propofol 146 s (95--260 [65--315]); P=0.001. The lowest bi-spectral index values were not different. The time of the lowest bi-spectral index values differed significantly: for etomidate 58 s (51--68 [38--100]), and for propofol 90 s (52--125 [38--172]); P=0.015. CONCLUSION: For nasotracheal fibreoptic intubation, where the tube is advanced after induction of anaesthesia, we still recommend etomidate because spontaneous breathing recovers faster than with propofol.     

Comparison of induction characteristics of four intravenous anaesthetic agents

The induction characteristics of thiopentone, etomidate and methohexitone have been compared to those of propofol (2,6 di-isopropyl phenol) in unpremedicated patients. Propofol 2.5 mg/kg caused significantly more hypotension, excitatory side effects and pain on injection at the dorsum of hand than thiopentone 5 mg/kg. However, with regard to the latter two sequelae, etomidate 0.3 mg/kg and methohexitone 1.5 mg/kg caused similar or more frequent upset. Propofol 2.0 mg/kg was equipotent with thiopentone 4.0 mg/kg in terms of successful induction of anaesthesia. Hypotension may contraindicate the use of propofol in the hypovolaemic or unfit patient.     

Intravenous ketamine attenuates injection pain and arterial pressure changes during the induction of anesthesia with propofol: a comparison with lidocaine

Objective: To compare the effects of lidocaine and ketamine pretreatment on injection pain and hypotension due to propofol induction. Design: Double blinded randomized controlled clinical trial. Place and Duration of the Study: Department of Anesthesiology, Surgical Intensive Care Unit and Pain Management, Dow University of Health Sciences and Civil Hospital, Karachi from February 2005 to December 2005. Patients and Methods: One hundred patients, age 20-60 years, of either gender, ASA I and II scheduled for elective gynaecological, urological, orthopedic or general surgical procedures under general anesthesia were randomly allocated into two groups i.e. group A to receive ketamine 0.5 mg/kg in volume of 2 ml with venous occlusion and group B to receive 2 ml of 1% lidocaine with venous occlusion as pretreatment before propofol induction. Venous occlusion was performed using rubber tourniquet after elevating the arm for 30 seconds, which was released 60 seconds after giving the pretreatment bolus and anesthesia was induced with propofol (2 mg/ml). Fifteen seconds after injection of 25%, the calculated dose of propofol and severity of injection pain was evaluated. Heart rate (HR) and noninvasive blood pressure were recorded pre-operatively, just before propofol induction, after propofol induction, immediately after intubation and 3 minutes after intubation. Results: Comparing the lidocaine group, the intensity and incidence of pain after propofol injection was lower in ketamine group but remained statistically insignificant. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly higher in ketamine group after induction with propofol. The maximum fall in SBP from baseline in ketamine group was 16% and 29.1% in lidocaine group, while maximum decrease in DBP in ketamine group was found to be12.66% vs. 26.47% in lidocaine group. There was no significant change in heart rate from baseline in either group. Conclusion: Ketamine pre-treatment with venous occlusion is an effective method in reducing pain and providing hemodynamic stability after propofol induction.