Prophylactic vs. therapeutic magnesium sulfate for shivering during spinal anesthesia

IntroductionShivering is one of the most common complications of neuraxial blockade. Some patients find shivering sensation worse than surgical pain. Therefore, both prevention and treatment of established shivering should be regarded as clinically relevant intervention in the perioperative period. The aim of our study is to compare the efficacy of magnesium sulfate when used for prevention or treatment of shivering following spinal anesthesia.MethodsIn this prospective, double blind, placebo controlled study, 120 ASA I, II patients undergoing surgery under spinal anesthesia were randomized into 3 groups. Following intrathecal injection, Group P (prophylactic) was given MgSO₄, 50 mg/kg I.V. bolus + 2 mg/kg/h infusion. Group T (therapeutic) was given MgSO₄ 50 mg/kg I.V. bolus as a therapy when shivering occurred. If shivering persisted, they received 25 mg/kg I.V. bolus. Group C (control) received saline at identical times. Meperidine was given as rescue if shivering persisted. Shivering grade 3/4 was regarded as significant. Core temperatures, incidence of shivering, and side effects were recorded.Main resultsTotal incidence of shivering, grade 3/4, was 15% in Group P, 45% in Group T, and 50% in Group C (p < 0.01). Magnesium sulfate significantly reduced the incidence and gain of shivering. The use of rescue meperidine was more in Group P (20%) and Group C (50%) compared to none in Group T (p < 0.05, p < 0.01, respectively). Significant reduction in core temperature occurred in the Mg groups compared to the control group p < 0.05. No correlation was found between patients who shivered and core temperature or ΔT. Hypotension was more frequent in Group P; nausea and vomiting were more in Mg groups than control group p < 0.05.ConclusionFollowing spinal anesthesia, prophylactic MgSO₄ infusion lowered incidence of shivering. When shivering did occur, MgSO₄ proved to be an effective treatment with minimal side effects.     

帕瑞昔布钠预防硬膜外麻醉后寒战的临床观察

目的探讨预先静注帕瑞昔布钠对硬膜外麻醉后寒战的预防效果。方法选择硬膜外麻醉下行择期经尿道前列腺切除手术患者120例,随机均分为两组。硬膜外麻醉前30 min分别静注帕瑞昔布钠40 mg(P组)或等容量生理盐水(C组)。观察麻醉及手术过程中寒战的发生率、寒战的严重程度及寒战发生前后体温变化。结果 P组患者寒战发生率为5%,而C组为25%,P组明显低于C组(P<0.05)。结论预先静注帕瑞昔布钠40 mg可有效预防硬膜外麻醉后寒战的发生。     

不同剂量纳布啡对腰-硬联合麻醉剖宫产产妇寒战的影响

目的 比较不同剂量纳布啡用于预防腰-硬联合麻醉剖宫产产妇寒战的效果及不良反应.方法 选择拟在腰-硬联合麻醉下行择期剖宫产单胎、足月妊娠产妇150例,年龄20～35岁,体重50～80 kg,ASAⅠ或Ⅱ级.采用随机双盲法将产妇随机分为五组:对照组(C组)、N1组、N2组、N3组和N4组,每组30例.胎儿娩出后夹毕脐带即刻...     

预先肌注曲马多对硬膜外麻醉后病人寒战的影响

目的 探讨肌肉注射曲马多对硬膜外麻醉后寒战的预防效果。方法 选择80例准备在硬膜外麻醉下行下腹、下肢或脊柱手术的成年患者,随机分为四组（每组20例）：肌注曲马多和氟哌利多组（TD组）;单纯曲马多组（T组）或氟哌利多组（D组）;对照组（C组）。于硬膜外注药前30分钟,TD组肌注曲马多1．5mg/kg和氟哌利多5mg;T组肌注曲马多1．5mg/kg;D组肌注氟哌利多5mg;C组不用药。观察麻醉及手术过程中寒战的发生率、寒战的严重程度及寒战发生前后体温变化。结果 寒战发生率TD组和T组均为5％,D组和C组分别为25％和35％,TD组和T组与C组比较差异显著（P＜0．05）。TD组哮睡发生率、T组恶心发生率较高。结论 肌注曲马多有助于预防低位硬膜外麻醉后寒战,应用时复合氟哌利多可减少曲马多的副作用。     

Effect of low dose phenylephrine infusion on shivering and hypothermia in patients undergoing cesarean section under spinal anesthesia: a randomized clinical trial

BackgroundShivering is a common complication of spinal anesthesia. Phenylephrine, due to its peripheral vasoconstrictive effect, may limit the core to periphery redistribution of body temperature following spinal anesthesia, and reduce hypothermia and shivering. We hypothesized that prophylactic phenylephrine infusion would reduce shivering and hypothermia in women undergoing cesarean section under spinal anesthesia.MethodsA two-arm randomized, double-blind, placebo-controlled trial in term pregnant patients undergoing cesarean section. In the phenylephrine group (n=75) prophylactic phenylephrine infusion was administered at 25 µg/min immediately after initiation of spinal anesthesia and continued until the end of the operative period. In the placebo group (n=75) a normal saline infusion was administered during the same period. The primary outcome was the incidence of shivering; secondary outcomes were severity of shivering, changes in nasopharyngeal (core) temperature, and incidence of hypotension and bradycardia.ResultsThe incidence of shivering in the phenylephrine and control groups was 24.0% (95% CI 14.3% to 33.7%) and 53.3% (95% CI 42.0% to 64.6%), respectively. The severity of shivering was greater in the control group (P=0.002) and the mean (±SD) end of surgery core temperature was significantly higher in the phenylephrine group (35.84°C ± 0.60) compared with controls (35.61°C ± 0.48) (P=0.009). The incidence of hypotension was higher in controls (53.4% vs. 2.7%; P <0.001) but bradycardia more frequent in group P (P=0.023).ConclusionThe incidence of shivering and degree of hypothermia were significantly reduced by a prophylactic phenylephrine infusion during cesarean section under spinal anesthesia.     

右美托咪定用于防治剖宫产术中寒战反应的适宜剂量

目的探讨右美托咪定用于防治剖宫产术中寒战反应的适宜剂量。方法选择单胎足月妊娠,拟在连续硬膜外麻醉下行择期剖宫产术的孕妇120例,随机分为四组,每组30例。胎儿娩出后,D1、D2、D3组分别输注负荷量右美托咪定0.2、0.5、0.8μg/kg,输注时间10 min,继以0.4μg·kg-1·h-1持续输注,关腹完毕后停药。N组则以0.1ml·kg-1·h-1的速率输注生理盐水。记录输注右美托咪定15min时产妇的寒战分级。结果 D2组和D3组寒战的发生率和程度分别低于D1组和N组(P0.05),而D2组和D3组差异无统计学意义。结论右美托咪定可有效防治剖宫术中寒战的发生,负荷量0.5μg/kg是一适宜剂量。     

Efficacy of prophylactic ketamine in preventing postoperative shivering

Background. Treatment with ketamine and pethidine is effectivein postoperative shivering. The aim of this study was to comparethe efficacy of low-dose prophylactic ketamine with that ofpethidine or placebo in preventing postoperative shivering. Methods. A prospective randomized double-blind study involved90 ASA I and II patients undergoing general anaesthesia. Patientswere randomly allocated to receive normal saline (Group S, n=30),pethidine 20 mg (Group P, n=30) or ketamine 0.5 mg kg^–1(Group K, n=30) intravenously 20 min before completion of surgery.The anaesthesia was induced with propofol 2 mg kg^–1, fentanyl1 µg kg^–1 and vecuronium 0.1 mg kg^–1. It wasmaintained with sevoflurane 2–4% and nitrous oxide 60%in oxygen. Tympanic temperature was measured immediately afterinduction of anaesthesia, 30 min after induction and beforeadministration of the study drug. An investigator, blinded tothe treatment group, graded postoperative shivering using afour-point scale and postoperative pain using a visual analoguescale (VAS) ranging between 0 and 10. Results. The three groups did not differ significantly regardingpatient characteristics. The number of patients shivering onarrival in the recovery room, and at 10 and 20 min after operationwere significantly less in Groups P and K than in Group S. Thetime to first analgesic requirement in Group S was shorter thanin either Group K or Group P (P<0.005). There was no differencebetween the three groups regarding VAS pain scores. Conclusion. Prophylactic low-dose ketamine was found to be effectivein preventing postoperative shivering.     

Shivering and neuraxial anesthesia

Shivering, which usually occurs as a thermoregulatory response to cold, may also occur following general or neuraxial anesthesia. Some of the causative factors of this type of shivering may be common to both, but some are particular to neuraxial anesthesia. Although shivering may have beneficial thermoregulatory effects, it places the body under increased physiological stress. In a broad sample of 21 studies, the median incidence of shivering related to neuraxial anesthesia in the control groups was 55%. Both pharmacological and nonpharmacological mechanisms have been found to be effective in reducing this shivering. This review aims to elucidate the mechanisms of the shivering that occurs during neuraxial anesthesia, and to examine strategies for prevention and treatment of this shivering.     

Propofol infusion for sedation during spinal anesthesia

Purpose The dose and time course of propofol infusion required to induce rapid sedation without oversedation during spinal anesthesia were investigated. Methods Forty patients scheduled for spinal and epidural anesthesia were studied. After premedication with intramuscular midazolam 0.04 mg·kg⁻¹, an epidural catheter was inserted, followed by spinal anersthesia at L4-L5 with 0.5% hyperbaric tetracaine with epinephrine. The infusion of propofol was started with 10 mg·kg⁻¹·h⁻¹ and was decreased to 5 mg·kg⁻¹·h⁻¹ at spontaneous eye closure. According to the increase or decrease of the sedation level, the infusion does was decreased or increased to half or twice the initial dose, respectively, to keep the Observer's Assessment of Alertness Sedation (OAAS) score at 3 or 4. Results Eye closure was observed at 1.0 ± 0.4 min after the start of insusion. The maintenance insusion dose to keep the OAAS score at 3 or 4 was about 2.5 mg·kg⁻¹·h⁻¹. Conclusion Propofol infusion, starting with 10 mg·kg⁻¹·h⁻¹, decreasing to 5 mg·kg⁻¹·h⁻¹ after 1 minute, and then decreasing to 2.5 mg·kg⁻¹·h⁻¹ after another min induced rapid onset of sedation and kept the OAAS score at 3 or 4 during spinal anesthesia.     

An attack of bronchial asthma during spinal anesthesia

Key words  bronchial asthma - spinal anesthesia     

右美托咪定复合氯胺酮在小儿麻醉中应用的研究进展

背景 右美托咪定(dexmedetomidine,Dex)是一种高选择性的α2肾上腺素受体激动剂,在小儿麻醉中的应用尚处于研究阶段.氯胺酮作为N-甲基-D-天冬氨酸受体拮抗剂,是小儿麻醉的常用药物.近年来,一些研究者将Dex复合氯胺酮用于小儿麻醉,取得了良好的临床效果. 目的 梳理Dex复合氯胺酮在小儿麻醉中应用的研究进展,为临床应用提供参考.内容 概述Dex和氯胺酮的药代动力学,以及两者复合麻醉在小儿患者创伤性检查、术前、术中以及困难气道处理中的应用.趋向 Dex复合氯胺酮在小儿麻醉中具有广阔的应用前景.     

奈福泮与曲马多预防剖宫产手术寒战的对比研究

目的比较奈福泮和曲马多对预防剖宫产手术中寒战的效果。方法拟在腰-硬联合麻醉下进行剖宫产手术的产妇210例,ASAⅠ或Ⅱ级,年龄20～35岁,体重50～75kg,随机分为三组：分别在麻醉开始前肌注奈福泮20mg（N组）,曲马多100mg（T组）,生理盐水2ml（C组）,每组70例。记录出现寒战的例数并对寒战强度进行评估。若患者在手术中出现Ⅱ级以上寒战,则随机静脉追加曲马多50mg（At组）或奈福泮10mg（An组）,观察注药后的并发症及寒战的缓解情况。用VAS对患者恶心呕吐进行评分。结果 N组和T组术中出现寒战例数明显少于C组（P〈0.05）,N组少于T组（P〈0.05）。产妇在追加曲马多或奈福泮5min后寒战均能缓解,但At组恶心、呕吐为中重度的例数多于An组（P〈0.05）,发生静脉注射痛的例数明显少于An组（P〈0.05）。结论奈福泮和曲马多均能有效预防剖宫产手术寒战的发生,但奈福泮的效果更好。两种药物能对已经发生的寒战有良好的治疗作用。在治疗寒战时,曲马多更容易引起恶心呕吐,而奈福泮则可引起静脉注射痛。     

小剂量布比卡因-芬太尼腰麻行全子宫切除术

目的　探讨鞘内阿片类药物与小剂量局部麻醉药联合应用是否可获得满意的腰麻效果。方法　 32例行全子宫切除术的病人随机分为A、B两组 ,每组 16例。A组腰麻用药为布比卡因5mg与芬太尼 2 0 μg ;B组布比卡因 10mg。收缩压小于 90mmHg或平均动脉压较基础水平下降 2 5 %定义为低血压。低血压用麻黄碱 5～ 10mg静注 ,最大剂量 5 0mg ,或去氧肾上腺素 10 0～ 2 0 0 μg静滴。结果　所有病人均获得满意的麻醉效果。A组有 1例使用麻黄碱 10mg。B组有 14例使用血管加压药物维持血压 ,麻黄碱平均使用量 35mg ,有 3例使用去氧肾上腺素。A组收缩压、舒张压、平均动脉压最低时分别下降到 (10 6± 2 2 )、(6 7± 16 )、(81± 13)mmHg ,而B组为 (86± 2 3)、(5 8± 14)、(6 8± 16 )mmHg ,差异显著。结论　小剂量布比卡因 5mg与 2 0 μg芬太尼联合使用行腰麻即可实施全子宫切除术。与 10mg布比卡因相比 ,小剂量联合用药较少引起低血压     

纳布啡治疗产妇腰-硬联合麻醉后寒战的临床效果

目的观察纳布啡治疗产妇腰-硬联合麻醉后寒战的临床效果及不良反应。方法选择择期腰-硬联合麻醉下行子宫下段剖宫产术,术中发生寒战Wrench 3/4级的产妇90例,年龄20~35岁,ASAⅠ或Ⅱ级。于寒战发生后随机双盲分为三组,每组30例,立即静脉注射生理盐水(C组)、纳布啡0.07 mg/kg(N组)和曲马多1 mg/kg(T组)。记录麻醉结束至寒战开始时间、药物处理后寒战消失时间、寒战治疗成功和复发的情况、改良OAA/S镇静评分,以及恶心呕吐、心动过缓、低血压等不良反应的发生情况。结果三组麻醉结束至寒战开始时间差异无统计学意义。N组和T组药物处理后寒战消失时间分别为(3.6±1.3)min和(4.2±2.2)min,明显短于C组的(14.3±7.3)min(P0.05)。N组和T组寒战治疗成功率分别为93.3%和90.0%,明显高于C组的16.7%(P0.05);复发率分别为7.1%和11.1%,明显低于C组的80.0%(P0.05)。N组OAA/S镇静评分明显高于C、T组(P0.05)。T组恶心呕吐发生率60.0%,明显高于C组和N组的20.0%和13.3%(P0.05);三组心动过缓、低血压发生率差异无统计学意义。结论纳布啡0.07 mg/kg可安全有效地治疗腰-硬联合麻醉产妇发生的寒战,且不良反应恶心呕吐的发生率较曲马多更低,具备可接受的镇静作用。     

右美托咪定与曲马多在下肢手术中预防寒战及镇静程度的比较

【摘要】〓目的〓比较右美托咪定与曲马多在防治腰硬联合麻醉下行下肢手术术中寒战的发生率及镇静程度。方法〓选择ASAⅠ~Ⅱ级择期经腰硬联合麻醉行下肢手术患者60例,随机分成3组:右美托咪定组(D组)采用静脉推注0.5 ?滋g/kg的右美托咪定),曲马多组(T组)静脉推注2 mg/kg的曲马多,空白对照组(C组)静脉推注等量生理盐水,3组均在实施腰硬联合麻醉前10 min内给完所需药量,比较三组患者血流动力学的变化、寒战的发生率及镇静评分。结果〓与C组比较,D组和T组均能降低患者寒战的发生率,差异有统计学意义(P<0.05);与T组比较,D组使用的右美托咪定能提高患者的镇静评分,且无恶心呕吐等不良反应的发生。结论〓右美托咪定与曲马多在腰硬联合麻醉前静脉泵注,能够有效降低寒战反应发生率,右美托咪定更能提高患者的镇静满意度,且无药物不良反应发生。     

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.     

Intravenous ketamine for prevention of severe hypotension during spinal anaesthesia

Spinal block causes paralysis of preganglionic sympathetic fibres, while ketamine induces activation of the sympathetic nervous system. Hypotension is a frequent complication during spinal anaesthesia and is associated with an increased risk of postoperative mortality. The aim of our study was to compare circulatory changes in patients who received either fentanyl or ketamine during spinal anaesthesia. Thirty patients (ASA I-III) scheduled to undergo spinal anaesthesia for osteosynthesis of hip fractures were allocated to receive either ketamine or fentanyl intravenously during the procedure. Immediately before anaesthesia, 7 ml/kg BW of an isotonic NaCl solution was administered i.v. Patients received either fentanyl 1.5 mg/kg BW i.v. before anaesthesia, or ketamine 0.7 mg/kg BW i.v. before anaesthesia, and 0.35 mg/kg BW 15 and 30 min after the first dose. No prophylactic vasopressor was used. During the first 40 min of anaesthesia a fluid load of 14 ml/kg BW was given i.v. If the mean arterial pressure (MAP) fell more than 20%, the infusion rate was increased. If the reduction in MAP exceeded 33% or if the systolic pressure decreased to less than 80 mmHg, patients were registered as haemodynamically unstable. In both groups the spinal anaesthesia caused a reduction in MAP. The MAP was lower in the fentanyl group than in the ketamine group at all times. In the fentanyl group six subjects developed a haemodynamically unstable condition, while only one subject in the ketamine group was registered as such (P less than 0.05). There was no significant change in heart rate in either group. We conclude that during spinal anaesthesia patients can in part be kept haemodynamically stable by intravenous administration of ketamine.     

Effects of low dose ketamine before induction on propofol anesthesia for pediatric magnetic resonance imaging

BACKGROUND: We aimed to investigate effects of low dose ketamine before induction on propofol anesthesia for children undergoing magnetic resonance imaging (MRI). METHODS: Forty-three children aged 9 days to 7 years, undergoing elective MRI were randomly assigned to receive intravenously either a 2.5 mg x kg(-1) bolus of propofol followed by an infusion of 100 microg x g(-1) x min(-1) or a 1.5 mg x kg(-1) bolus of propofol immediately after a 0.5 mg x kg(-1) bolus of ketamine followed by an infusion of 75 microg x kg(-1) x min(-1). If a child moved during the imaging sequence, a 0.5-1 mg x kg(-1) bolus of propofol was given. Systolic and diastolic blood pressures, heart rate, peripheral oxygen saturation and respiratory rates were monitored. Apnea, the requirement for airway opening maneuvers, secretions, nausea, vomiting and movement during the imaging sequence were noted. Recovery times were also recorded. RESULTS: Systolic blood pressure and heart rate decreased significantly in the propofol group, while blood pressure did not change and heart rate decreased less in the propofol-ketamine group. Apnea associated with desaturation was observed in three patients of the propofol group. The two groups were similar with respect to requirements for airway opening maneuvers, secretions, nausea-vomiting, movement during the imaging sequence and recovery time. CONCLUSIONS: Intravenous administration of low dose ketamine before induction and maintenance with propofol preserves hemodynamic stability without changing the duration and the quality of recovery compared with propofol alone.     

Control of shivering during regional anaesthesia: prophylactic ketamine and granisetron

BACKGROUND: The aim of the present study was to compare placebo, ketamine, granisetron and a combination of ketamine and granisetron in the prevention of shivering caused by regional anaesthesia. METHODS: In this prospective, randomized, double-blind study, 160 ASA I and II patients undergoing urological surgery were included. Subarachnoid anaesthesia was performed in all patients with bupivacaine 15 mg. The patients were randomly allocated to receive saline (group P, n= 40), ketamine 0.5 mg (group K, n= 40), granisetron 3 mg (group G, n= 40) or ketamine 0.25 mg + granisetron 1.5 mg (group KG, n= 40). Shivering was graded as 0 = no shivering, 1 = piloerection or peripheral vasoconstriction but no visible shivering, 2 = muscular activity in only one muscle group, 3 = muscular activity in more than one muscle group but not generalized, and 4 = shivering involving the whole body. If 15 min after spinal anaesthesia and concomitant administration of a prophylactic dose of one of the study drugs, the patients shivered according to at least grade 3, the prophylaxis was regarded as ineffective and intravenous (i.v.) pethidine 25 mg was administered. RESULTS: After 15 min, the number of patients with observed shivering was 22 in group P, 6 in group G, 7 in group GK and 0 in group K. The difference between group K and all the other groups was statistically significant (P < 0.0001). The number of patients with a shivering score of 3 was statistically significantly higher in group P compared with the other groups. CONCLUSION: The prophylactic use of 0.5 mg/kg i.v. ketamine was effective in preventing shivering developed during regional anaesthesia.