Nefopam and clonidine in the prevention of postanaesthetic shivering

Postanaesthetic shivering affects up to 70% of patients after general anaesthesia, and may be very distressing. Various drugs have been used to treat or prevent postanaesthetic shivering, but the ideal one has not yet been found. Sixty patients undergoing elective abdominal or orthopaedic surgery under general anaesthesia were included in a randomised, double-blind study. Patients received clonidine (3 microgram.kg-1), nefopam (0.15 mg.kg-1) or saline 0.9% as a placebo at the end of surgery, prior to extubation. Nefopam and clonidine significantly reduced the incidence and severity of shivering in comparison with the placebo. The recovery time, between the end of anaesthesia and extubation, was significantly longer in the clonidine-treated patients [13.6 (5.2) min] than in either the nefopam [9.6 (2.8) min] or the placebo [10.0 (5.4) min] groups. Mean arterial blood pressure and heart rate were significantly lower in the clonidine group compared with both other groups. Our results suggest that nefopam and clonidine are effective in the prevention of postanaesthetic shivering. However, following clonidine administration the recovery time was prolonged and hypotension was significantly greater than after nefopam.     

Nefopam and tramadol for the prevention of shivering during neuraxial anesthesia

BACKGROUND AND OBJECTIVES: In patients undergoing neuraxial anesthesia, heat loss and core-to-peripheral redistribution of body heat causes the core temperature to decrease. The shivering threshold is therefore reached soon, and more shivering is required to prevent further hypothermia. Because shivering has deleterious metabolic and cardiovascular effects, it should ideally be prevented by pharmacologic or other means. We evaluated the usefulness of intravenous (IV) nefopam and tramadol in preventing and reducing the severity of shivering in patients undergoing neuraxial anesthesia for orthopedic surgery. METHODS: Ninety patients, scheduled for neuraxial anesthesia (epidural or subarachnoid) for lower limb orthopedic surgery, were prospectively enrolled. Patients were randomly assigned to 1 of 3 groups. Immediately before neuraxial anesthesia, 30 patients received 0.15 mg/kg(-1) IV nefopam in 10 mL saline, 30 patients received 0.5 mg/kg(-1) IV tramadol in 10 mL saline, and a control group of 30 patients received 10 mL IV saline. Neuraxial anesthesia was induced at the L3-L4 or L4-L5 interspaces with 1 mg/kg(-1) mepivacaine for epidural anesthesia and 0.2 mg/kg(-1) for subarachnoid anesthesia. An investigator blinded to the antishivering drug injected recorded the frequency and degree of shivering. RESULTS: The overall frequency and the intensity of shivering was significantly lower in patients treated with nefopam than in those treated with tramadol or placebo (P <.05 and P <.01) and in patients treated with tramadol than in those treated with placebo (P <.05). CONCLUSIONS: As a pharmacologic means of preventing shivering in patients undergoing neuraxial anesthesia, nefopam may hold the greatest promise.     

Anaesthesia and sedation for neuroradiological imaging and interventional neuroradiology

Neuroradiology has had a long association with anaesthesia, and the development of new imaging techniques have been made possible by developments in anaesthetic practice. However, recent advances in diagnostic neuroradiology demand new refinements in anaesthetic technique. Further, the growth of interventional and image guided therapeutic procedures has posed an entirely new set of challenges, not least because it opens up the option of treating patients who may have been previously considered too high a risk for operative intervention. Of particular interest are the developments in intravascular interventional neuroradiology and interventional magnetic resonance imaging. The availability of novel anaesthetic agents and techniques, along with new commercially available equipment, provides the prospect of being able to meet these challenges and deliver safe and effective anaesthesia in demanding environments.     

异丙酚靶控输注用于硬膜外麻醉病人清醒镇静的可行性

目的探讨异丙酚靶控输注用于硬膜外麻醉病人清醒镇静的可行性及所需靶控血药浓度.方法50例在硬膜外麻醉下行下腹部及下肢手术病人,以血浆室为靶控目标,予以异丙酚TCI清醒镇静.靶控血药浓度最初设定为0.5μg/ml,在与效应室异丙酚浓度达平衡后3min以0.1μg/ml递增,直至OAA/S评分降至3分,并抽取病人各时点静脉血3mi,采用高效液相色谱分析法测定异丙酚血药浓度,确定不同OAA/S评分时对应靶控血药浓度及其与BIS相关性,评估靶控输注系统的性能.结果预期误差的中位数MDPE=-23.1%,预期误差绝对值的中位数MDAPE=27.6%6,清醒镇静深度(OAA/S评分3分)时所需的异丙酚靶控血药浓度为(1.74±0.13)μg/ml.BIS与TCI血药浓度具有良好的相关性(r=-0.80,P＜0.05).结论异丙酚靶控输注用于硬膜外麻醉病人清醒镇静具有可控性良好,病人镇静深度适宜,血液动力学影响小,适用于临床推广.     

Conscious sedation for interventional neuroradiology: a comparison of midazolam and propofol infusion

Purpose

The aim of this study was to compare two conscious sedation techniques, midazolam (M) and propofol (P), for interventional neuroradiology by assessment of the incidence of complications and satisfaction scores.

Methods

Forty patients were randomized to receive 0.75 μg · kg^?1 fentanyl and a M or P bolus followed by an infusion; (M I5 μg · kg^?1 + 0.5 μg · kg^?1 · min^?1: P 0.5 mg · kg^?1 + 25 μg · kg^?1 min^?1). The incidences of complications and untoward events requinng intervention were documented. These included respiratory depression, excessive pain, inappropriate movements and the inability to examine the patient. The satisfaction of the anaesthetic technique from the perspective of both the neuroradiologist and the patient was scored.

Results

The incidence and types of complications were not different between the two groups. Pain occurred in 12 patients (6M, 6P), inappropriate movements in 17 (7M, 10P) and respiratory changes in 10 patients (2M, 8P).

Conclusions

Both techniques were satisfactory and the incidence of complications was similar for both groups.     

Comparison of ondansetron and meperidine for prevention of shivering in patients undergoing spinal anesthesia

BACKGROUND AND OBJECTIVES: Perioperative hypothermia is a common problem in anesthesia practice. Regional anesthesia, like general anesthesia, influences the thermoregulatory process. The aim of our study was to compare the efficacy of ondansetron and meperidine in the prevention of shivering during and after spinal anesthesia. METHODS: In this double-blind study, 75 patients were randomized into 3 groups. Group O and Group M were given ondansetron 8 mg and meperidine 0.4 mg/kg intravenously immediately before spinal anesthesia, respectively. Group C received saline at identical times. The core temperatures and the incidence of shivering were recorded. Association between maximum block height and mean rectal temperatures of the patients were also evaluated. RESULTS: The core temperature was preserved in both ondansetron and meperidine groups with respect to the control group. Shivering was observed in 8% of patients in groups O and M and 36% in group C. The correlation between maximum block height and mean rectal temperatures was lost in the ondansetron and meperidine groups. CONCLUSION: Ondansetron and meperidine have similar anti-shivering effects. In addition, both ondansetron and meperidine altered the correlation between the core temperature and block level during spinal anesthesia.     

The risk of sedation/analgesia in hemodialysis patients undergoing interventional procedures

Data derived from a large cohort of hemodialysis patients (12,896) undergoing dialysis access maintenance procedures being performed by interventional nephrologists were analyzed to determine the safety of sedation/analgesia (S/A) in a freestanding facility. Data collected included patient demographics, procedures performed, time of procedures, drugs used, doses used, and complications that occurred. Four high-risk groups were identified based upon age, pulmonary status, and over all physical status. These were compared to the total cohort. Midazolam, fentanyl, or a combination of the two were used. Within the total cohort of patients, midazolam alone was used most commonly (94.7%). The total mean dose of midazolam when used alone was 3.4 mg. The dosages used in the high-risk groups tended to be only slightly lower (3-3.2 mg). This setting appears to be safe for hemodialysis patients, even those in high-risk subgroups having these types of procedures. The types of drugs and the dosages that are commonly used do not appear to be associated with an unacceptable risk to the hemodialysis patient. A nephrologist that is not specialty trained in anesthesia is able to provide S/A safely in a freestanding facility.     

Intensive care unit management of interventional neuroradiology patients

The management of interventional neurologic patients in the intensive care unit is based on their underlying disease for the most part. Patients with ischemic stroke are largely managed like patients with ischemic stroke who have not undergone interventional procedures, and the same is true for those with an aneurysmal subarachnoid hemorrhage or intracerebral hemorrhage secondary to an arteriovenous malformation, for example.Having said this, there are some special considerations that require special mention when it comes to managing patients after catheter-based procedures.     

A comparison of two sedation techniques for neuroradiology

Two groups of 25 patients were sedated during neuroradiological investigation. The first group was sedated with fentanyl and midazolam while the other was given fentanyl and a two-stage infusion of propofol in a subanaesthetic dose. Both techniques resulted in satisfactory sedation and recovery, although those who received propofol were more likely to recall their journey from the X-ray department back to the ward. Sedation in both groups resulted in unacceptable PaO2 values in some patients which could subsequently be corrected by administration of supplementary oxygen.     

Pharmacokinetics of propofol during conscious sedation using target- controlled infusion in anxious patients undergoing dental treatment

Infusion of propofol by a target-controlled infusion (TCI) system is effective in achieving conscious sedation for anxious patients presenting for dental surgery. It is a common clinical observation that anxious patients require more anaesthetic drugs than non-anxious individuals. In study 1 we have defined blood propofol concentrations necessary for conscious sedation in both anxious (n = 23) and non- anxious (n = 18) patients. The pump performance of the TCI system, using Gepts' pharmacokinetic model, was evaluated in these two patient groups. Subsequently, clearance of propofol was compared in the two groups. Mean measured venous serum propofol concentrations obtained between 20 and 35 min after the optimal sedation level was reached were 1.6 (SD 0.2) micrograms ml-1 in the anxious patients compared with 1.7 (0.3) micrograms ml-1 in the control group (study 1) and 1.4 (0.27) micrograms ml-1 in study 2. The pump systematically overpredicted measured propofol concentrations in both groups (study 1). There was no significant difference in propofol clearance between the two groups. In study 2, an optimized set of microconstants was derived which should more accurately predict the pharmacokinetic profile of the anxious population and this set was tested prospectively in another group of 12 anxious dental patients. Bias and precision with the optimized kinetic set were significantly less than the values obtained in study 1. We conclude that there was no significant pharmacokinetic differences between anxious and non-anxious subjects receiving subanaesthetic doses of propofol for conscious sedation.      

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...     

右美托咪定预防骨科脊柱手术患者全麻后寒战的临床观察

目的 观察右美托咪定对骨科脊柱手术患者全麻后寒战的预防作用.方法 全麻下行脊柱手术的患者90例,随机均分为右美托咪定组(D组)和对照组(C组).D组麻醉诱导后泵注右美托咪定(负荷剂量0.5 μg/kg,10 min泵完,以0.4 μg·kg-1·h-1维持);C组泵注生理盐水,泵注速度及方法同D组.监测并记录诱导前(基础值)、插管后5、15、30、60 min及拔管前后HR、MAP、SpO2、肛温(T),观察并记录术后入麻醉后恢复室(PACU)即刻、30、60 min VAS评分、Ramsay镇静评分(RSS);记录寒战分级、寒战出现的时间.结果 与基础值及与C组比较,插管后30、60 min、拔管前和拔管后D组HR明显减慢(P＜0.05);拔管前、拔管后D组MAP明显降低(P＜0.01).与基础值比较,插管后30、60 min和拔管前、拔管后两组患者T降低(P＜0.05).D组术后寒战发生率明显降低(P＜0.01);入PACU后即刻、30 min D组VAS评分明显降低(P＜0.05或P＜0.01);入PACU后即刻、30、60 min D组RSS评分明显升高(P＜0.01).结论 术中泵注右美托咪定可有效预防骨科脊柱手术患者全麻后寒战的发生.     

The prevention of emergence agitation with tropisetron or clonidine after sevoflurane anesthesia in small children undergoing adenoidectomy

Postoperative agitation is a common problem after sevoflurane anesthesia in children. In the present study, we evaluated if tropisetron or clonidine could reduce the incidence of postoperative agitation after day case adenoidectomy in small children. We included 75 unpremedicated children aged 1-7 yr who were randomly assigned to receive either placebo, tropisetron (0.1 mg/kg) or clonidine (1.5 microg/kg) after anesthesia induction. Anesthesia was induced and maintained with sevoflurane. Patients also received alfentanil (20 microg/kg) and diclofenac (1 mg/kg). Postoperative pain was treated with IV oxycodone (0.05 mg/kg). Time to achieve discharge criteria was recorded. Modified pain/discomfort scale was used assess the postoperative behavior. The incidence of postoperative agitation was significantly less (32%, 8/25 patients) in the tropisetron group compared with placebo (62%, 16/26 patients), P < 0.05). Clonidine could not prevent agitation (incidence 54%, 13/24). No adverse effects were noted during the study. Discharge times were similar between the groups (between 80 and 99 min on average). In conclusion, tropisetron 0.1 mg/kg significantly reduced the incidence of postoperative agitation after sevoflurane anesthesia. Clonidine 1.5 microg/kg did not differ from placebo with respect to postoperative agitation.     

Epidural infusion of clonidine or clonidine plus ropivacaine for postoperative analgesia in children undergoing major abdominal surgery

STUDY OBJECTIVE: To investigate the analgesic efficacy and safety of epidural infusion of clonidine in children undergoing major abdominal surgery. DESIGN: Randomized open-label study. SETTING: Postoperative anesthetic unit and pediatric ward of a metropolitan hospital. PATIENTS: Forty children aged 0 to 3 years undergoing major abdominal surgery. INTERVENTIONS: Children were randomly allocated to receive a 24-hour epidural infusion of clonidine 1 microg.mL(-1) at rate of 0.2 mL.kg -1.h -1 preceded by a bolus of 2 microg.kg -1 (CLON group) or a mixture of clonidine 1 microg.mL -1 and ropivacaine 0.1% at rate of 0.2 mL.kg -1.h -1. Both groups received intravenous (IV) ketoprofen 2 mg.kg -1 every 8 hours. Breakthrough pain was treated with IV tramadol 1 mg.kg(-1). MEASUREMENTS: Tramadol requirement, sedation and respiratory and hemodynamic changes were measured. MAIN RESULTS: Approximately 77% and 59.3% of the CLON and CLON+ROPIV groups, respectively, required no tramadol or only one dose over a 24-hour period. Except for those patients who exhibited frequent coughing during the night (4 and 5 patients in the CLON and CLON+ROPIV groups, respectively), no study patients required an analgesic and all had good sleep quality during the first night. Sedation and decreased systolic blood pressure were observed after the clonidine bolus was given. CONCLUSION: For children undergoing major abdominal surgery, the addition of epidural infusion of clonidine or clonidine plus ropivacaine to IV ketoprofen provided good analgesia quality for postoperative rest pain.