Cross-tolerance between spinal neostigmine and morphine in the rat

Background. Direct or indirect acting cholinergic muscarinicagonists such as neostigmine, are potent antinociceptives whenadministered intrathecally (i.t.). This study examines whetherspinal neostigmine tolerance and cross-tolerance to spinal morphineoccurs. Methods. Rats (32/group) were implanted with miniosmotic pumpsdelivering either i.t. saline 1 µl h^–1 (S), morphine10 nmol µl^–1 h^–1 (M), or neostigmine 3 nmolµl^–1 h^–1 (N). Latencies (infrared thermalwithdrawal rear paw) were measured daily for 6 days after whichfour animals from each group were given one i.t. challenge doseof morphine (m) 0.1, 1, 10, or 100 nmol, or neostigmine (n)0.3, 3, 10, or 30 nmol. Results. Neostigmine and morphine-infused animals both developedtolerance to spinal neostigmine, but neostigmine-infused animalsshowed no significant cross-tolerance to spinal morphine; meanED₅₀ nmol (CI 95%) dose–response values were Sn 2.6 (1.9–3.5),Mn 15.6 (9.9–24.6)*, Nn 18.7 (11.7–29.8)*, Sm 0.7(0.4–1.1), Nm 1.2 (0.8–2.0), Mm 152 (50–461)*(*significance vs saline infused control group). Conclusion. Thus, unidirectional cross-tolerance from morphineto neostigmine was evident. Previous studies suggest morphinehas a cholinergic mechanism of action partially accounting forits antinociceptive effect, which may explain this observedunidirectional cross-tolerance. Br J Anaesth 2003; 91: 427–9     

Intrathecal sufentanil and morphine for post-thoracotomy pain relief

In this double-blind randomized study we compared a group of15 patients undergoing thoracotomy who received a spinal injectionof sufentanil 20 µg combined with morphine (200 µg)after induction of general anaesthesia with a control groupof the same size. Post-operative pain was rated on a visualanalogue scale (VAS) and a verbal rating scale at rest and witha VAS on coughing. In the recovery room, patients received titratedi.v. morphine until the VAS score was <30, and were followedby patient-controlled analgesia (PCA) for 72 h. The intrathecalsufentanil and morphine group had a lower intra-operative requirementfor i.v. sufentanil and needed less i.v. morphine for titrationin the recovery room. I.v. PCA morphine consumption and painscores were lower in the active group than in the control groupduring the first 24 h. There were no differences afterthis time. Spirometric data (peak expiratory flow, forced vitalcapacity and forced expiratory volume in 1 s) were similarin the two groups. We conclude that the combination of intrathecalsufentanil and morphine produces analgesia of rapid onset andwith a duration of 24 h. Br J Anaesth 2001; 86: 236–40.     

Dextromethorphan and intrathecal morphine for analgesia after Caesarean section under spinal anaesthesia

Background. Dextromethorphan is an N-methyl-D-aspartic acidantagonist which can attenuate acute pain with few side-effects.In this prospective, randomized, double-blind study of dextromethorphanand intrathecal morphine, we investigated postoperative pain,pruritus, nausea and vomiting in women undergoing Caesareansection under spinal anaesthesia. Methods. Women were allocated randomly to one of six groups,to receive intrathecal morphine 0.05, 0.1 or 0.2 mg plusoral dextromethorphan 60 mg or placebo. Results. The addition of dextromethorphan did not reduce postoperativepain scores (P=0.83). Compared with women receiving intrathecalmorphine 0.05 mg, women receiving higher doses had a significantlyhigher incidence of nausea and vomiting [odds ratio for intrathecalmorphine 0.1 mg, 4.0 (95% confidence interval 1.2–14.1);for intrathecal morphine 0.2 mg, 7.9 (2.3–27.1)].Compared with women receiving intrathecal morphine 0.05 mg,women receiving higher doses also had a significantly higherincidence of pruritus [odds ratio for intrathecal morphine 0.1 mg,3.2 (95% confidence interval 1.3–8.2); for intrathecalmorphine 0.2 mg, 3.7 (1.4–9.5)]. Women receivingdextromethorphan had a lower incidence of nausea and vomiting[odds ratio 2.6 (1.1–6.3)]. Conclusions. Postoperative pain after Caesarean section underspinal anaesthesia was not reduced by the addition of oral dextromethorphanto a multimodal approach including intrathecal morphine. Br J Anaesth 2003; 90: 653–8     

Remifentanil preconditioning confers delayed cardioprotection in the rat

BACKGROUND: Preconditioning with remifentanil (RPC) provides immediate cardioprotection in rats via all three types of opioid (OP) receptor. This study sought to investigate whether remifentanil also confers delayed cardioprotection via OP receptors. METHODS: Male rats received preconditioning either by ischaemia (IPC; 5 min occlusion, 5 min reperfusion x 3) or with remifentanil (RPC; 1, 5, 10, and 20 microg kg(-1) min(-1), 20 min infusion). After 24 h, all animals were subjected to 30 min occlusion of the left coronary artery and 2 h of reperfusion. Subsequently, the time-course effect of RPC (10 microg kg(-1) min(-1), 20 min infusion) was determined at 12, 16, 24, 32, 36, and 48 h intervals, using the same experimental procedure. The effect of RPC (10 microg kg(-1) min(-1), 20 min infusion) and IPC in the presence of selective OP receptor antagonists was evaluated at the 24 h interval. Infarct size (IS), as a percentage of the area at risk (AAR), was determined. RESULTS: Pre-treatment with remifentanil at 1, 5, 10, and 20 microg kg(-1) min(-1) significantly reduced the IS/AAR at 24 h with the maximum effect at 10 microg kg(-1) min(-1). Remifentanil at 10 microg kg(-1) min(-1) significantly reduced the IS at 12 h [32.5 (sd 9.1)%]; 16 h [26.1 (2.8)%]; 24 h [19.5 (5.0)%]; 32 h [31.2 (9.1)%]; and 36 h [36.4 (9.4)%] after drug administration. The maximal reduction in IS was seen at 24 h and the effect completely disappeared at 48 h [36.4 (9.4)%]. The protective effect of RPC was abolished or significantly attenuated by blockade of any of the three OP receptors with selective antagonists. CONCLUSIONS: Like IPC, remifentanil produces delayed cardioprotection in anaesthetized rats 12-36 h after administration. The protective effect is mediated via all three OP receptors.     

Predictive factors of early morphine requirements in the post-anaesthesia care unit (PACU)

Use of morphine by titration in the post-anaesthesia care unit(PACU) is often the first step in postoperative pain management.This approach provides rapid analgesia but shows a wide inter-individualvariability in morphine requirements and may prolong patientstay in the PACU. The aim of this study was to identify thepatient characteristics, surgical, anaesthetic, and postoperativefactors predictive of early morphine requirements. The studyincluded 149 patients undergoing various non-cardiac surgicalprocedures under general anaesthesia. In the multiple regressionanalysis of nine variables, only ethnicity (Caucasian), emergencysurgery, major surgery, surgery exceeding 100 min, and painscore on arrival in PACU were predictive factors of morphinerequirements. This observational study identifies for the firsttime independent predictive factors of morphine requirementsin the early postoperative period. Future studies are warrantedto evaluate the impact of intervention on these factors andany resulting improvement in postoperative pain treatment. Br J Anaesth 2001; 87: 385–9     

Rectal acetaminophen does not reduce morphine consumption after major surgery in young infants

BACKGROUND: The safety and value of acetaminophen (paracetamol) in additionto continuous morphine infusion has never been studied in newbornsand young infants. We investigated the addition of acetaminophento evaluate whether it decreased morphine consumption in thisage group after major thoracic (non-cardiac) or abdominal surgery. METHODS: A randomized controlled trial was performed in 71 patients giveneither acetaminophen 90–100 mg kg^–1 day^–1orplacebo rectally, in addition to a morphine loading dose of100 µg kg^–1 and 5–10 µg kg^–1h^–1 continuous infusion. Analgesic efficacy was assessedusing Visual Analogue Scale (VAS) and COMFORT scores. Extramorphine was administered if VAS was 4. RESULTS: We analysed data of 54 patients, of whom 29 received acetaminophenand 25 received placebo. Median (25–75th percentile) agewas 0 (0–2) months. Additional morphine bolus requirementsand increases in continuous morphine infusion were similar inboth groups (P = 0.366 and P = 0.06, respectively). There wasno significant difference in total morphine consumption, respectively,7.91 (6.59–14.02) and 7.19 (5.45–12.06) µg kg^–1 h^–1for the acetaminophen and placebo group (P = 0.60). COMFORT[median (25–75th percentile) acetaminophen 10 (9–12)and placebo 11 (9–13)] and VAS [median (25–75thpercentile) acetaminophen 0.0 (0.0–0.2) and placebo 0.0(0.0–0.3)] scores did not differ between acetaminophenand placebo group (P = 0.06 and P = 0.73, respectively). CONCLUSIONS: Acetaminophen, as an adjuvant to continuous morphine infusion,does not have an additional analgesic effect and should notbe considered as standard of care in young infants, 0–2months of age, after major thoracic (non-cardiac) or abdominalsurgery.     

Paediatric ventilatory effects of morphine and buprenorphine revisited

The study describes long term ventilatory effects of 50 or 100 μg·kg^-1 of morphine or 1.5 or 3.0 μg·kg^-1 of buprenorphine when given in repeated intravenous (i.v.) doses, in a double blind fashion, to achieve equal levels of analgesia after thoracotomy. The patients were 56 children, six months to six years of age. Ventilatory rate (VR) was measured over the 24 h study period, and arterial carbon dioxide tension (Paco₂) was measured on arrival in the Paediatric Intensive Care Unit (PICU) and at 1, 6, 12 and 18 h. In the buprenorphine groups VRs progressively decreased during the first 2 h and remained significantly lower (P < 0.05) than in the morphine groups for 7 h. For the rest of the study period there were no differences. The Paco₂ values did not differ significantly at any point. For safety, prolonged observation of children is needed after intravenous administration of buprenorphine to ensure the ventilatory rate has stabilized.     

Cerebral and lung kinetics of morphine in conscious sheep after short intravenous infusions

Background. The analgesic effects of morphine are delayed relativeto its concentration in blood. The rate of equilibration ofmorphine between blood and brain may contribute to this delay,but the kinetics of this process have not been modelled. Thiswas determined in conscious instrumented sheep. The lung kineticsof morphine were also determined given their importance in definingsystemic kinetics after i.v. bolus administration. Methods. Sheep were given short i.v. infusions of morphine (30mg over 4 min). Cerebral kinetics were inferred from arterio–sagittalsinus concentration gradients and cerebral blood flow, and lungkinetics from the pulmonary artery–aortic gradient andcardiac output. These data were fitted to flow- and membrane-limitedmodels of the kinetics in each organ. Results. Morphine had minimal cardiovascular effects, did notalter cerebral blood flow and caused insignificant respiratorydepression. Lung kinetics were best described by a single distributionvolume (2036 ml) with a first-order loss (1370 ml min^–1),which was attributed to deep distribution. The cerebral kineticsof morphine were characterized by a significant permeabilitybarrier. Permeability across the barrier (7.44 ml min^–1)was estimated with good precision, and was approximately one-fifthof the nominal cerebral blood flow. The distribution volumeof morphine in the brain was estimated with less precision,but was described by a brain:blood partition coefficient ofapproximately 1.4. The time required for 50% equilibration betweenbrain and blood concentrations was approximately 10.3 min. Conclusion. The cerebral equilibration of morphine was relativelyslow, and was characterized by significant membrane limitation. Br J Anaesth 2003; 90: 750–8     

Hormonal and metabolic stress responses after major surgery in children aged 0-3 years: a double-blind, randomized trial comparing the effects of continuous versus intermittent morphine

Children aged 0–3 yr were stratified for age and randomizedto receive either continuous morphine (CM, 10 µg kg^–1 h^–1)with three-hourly placebo boluses or intermittent morphine (IM,30 µg kg^–1 every 3 h) with a placeboinfusion for postoperative analgesia. Plasma concentrationsof epinephrine, norepinephrine, insulin, glucose and lactatewere measured before and at the end of surgery and 6, 12 and24 h after surgery. Pain was assessed with validated painscales [the COMFORT scale and a visual analogue scale (VAS)]with the availability of additional morphine doses. Minor differencesoccurred between the randomized treatment groups, the oldestIM group (aged 1–3 yr) having a higher blood glucoseconcentration (P=0.003), mean arterial pressure (P=0.02) andCOMFORT score (P=0.02) than the CM group. In the neonates, preoperativeplasma concentrations of norepinephrine (P=0.01) and lactate(P<0.001) were significantly higher, while the postoperativeplasma concentrations of epinephrine were significantly lower(P<0.001) and plasma concentrations of insulin significantlyhigher (P<0.005) than in the older age groups. Postoperativepain scores (P<0.003) and morphine consumption (P<0.001)were significantly lower in the neonates than in the older agegroups. Our results show that continuous infusion of morphinedoes not provide any major advantages over intermittent morphineboluses for postoperative analgesia in neonates and infants. Br J Anaesth 2001; 87: 390–9     

Effect of combining dexmedetomidine and morphine for intravenous patient-controlled analgesia

Background: Perioperative use of dexmedetomidine is associated with reductionin postoperative analgesic requirements. This study examinedwhether dexmedetomidine added to i.v. patient-controlled analgesia(PCA) morphine could improve analgesia while reducing opioid-relatedside-effects. Methods: In this double-blinded, randomized, controlled study, 100 womenundergoing abdominal total hysterectomy were allocated to receiveeither morphine 1 mg ml^–1 alone (Group M) or morphine1 mg ml^–1 plus dexmedetomidine 5 µg ml^–1 (GroupD) for postoperative i.v. PCA, which was programmed to deliver1 ml per demand with a 5 min lockout interval and no backgroundinfusion. Cumulative PCA requirements, pain intensities, cardiovascularand respiratory variables, and PCA-related adverse events wererecorded for 24 h after operation. Results: Compared with Group M, patients in Group D required 29% lessmorphine during the 0–24 h postoperative period and reportedsignificantly lower pain levels from the second postoperativehour onwards and throughout the study. Whereas levels of sedationwere similar between the groups at each observational time point,decreases in heart rate and mean blood pressure from presurgerybaseline at 1, 2, and 4 h after operation were significantlygreater in Group D (by a range of 5–7 beats min^–1and 10–13%, respectively). The 4–24 h incidenceof nausea was significantly lower in Group D (34% vs 56.3%,P<0.05). There was no bradycardia, hypotension, oversedation,or respiratory depression. Conclusions: The addition of dexmedetomidine to i.v. PCA morphine resultedin superior analgesia, significant morphine sparing, less morphine-inducednausea, and was devoid of additional sedation and untoward haemodynamicchanges.     

Comparison between patient-controlled analgesia and subcutaneous morphine in elderly patients after total hip replacement

Background. The goal of this study was to evaluate the effectivenesson postoperative pain, and cognitive impact, of patient-controlledanalgesia (PCA) compared with subcutaneous (s.c.) injectionsof morphine in elderly patients undergoing total hip replacement(THR). Methods. Forty patients older than 70 yr were randomly assignedto two different postoperative analgesic techniques for 48 h:i.v. PCA morphine (dose, 1 mg; lockout interval, 8 min; PCAgroup) or regular s.c. morphine injections (SC group). Postoperativepain was assessed at rest and when moving, using a visual analoguescale (VAS) every 4 h. A Mini Mental Status (MMS) examinationwas used to assess cognitive functions before surgery, at 2h, 24 h and 48 h after surgery, and at hospital discharge. Side-effectswere also recorded systematically during the first 48 h aftersurgery. Results. The PCA group showed significantly lower pain scoresthan the SC group both at rest and during mobilization. However,the clinical significance of pain scores was weak. There wasno intergroup difference in postoperative MMS scores. The incidenceof side-effects was similar in both groups. Conclusions. We conclude that in healthy elderly subjects undergoingTHR, the flexibility of the analgesic regimen is more importantthan the route of administration with regard to efficacy, adverseeffects and recovery of cognitive function. Br J Anaesth 2003; 90: 53–7     

Protective effects of dexmedetomidine on ischaemia-reperfusion injury in an experimental rat model of priapism

The study aimed to investigate the effects of dexmedetomidine against ischaemia-reperfusion injury occurring after priapism in a model of induced-priapism in rats. A total of 18 male rats were randomised into three groups. Group 1 was the control group. A priapism model was performed rats in Group 2 and then ischaemia-reperfusion injury was evaluated. Group 3 had similar procedures to the rats in Group 2. Rats in Group 3 additionally had 100 μg/kg dexmedetomidine administered intraperitoneally immediately after reperfusion. Blood and tissue samples were analysed. Biochemical analysis of blood samples revealed a decrease in the levels of the pro-inflammatory cytokines including interleukin-1 beta (IL-1 Beta), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNF-alpha) in Group 3 compared to Group 2 (p:.04, p:.009 and p:.009, respectively). Similarly, the highest malondialdehyde (MDA) level was in Group 2 (p:.002). The levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were significantly higher in Group 3 than that of Group 2 (p:.037 and p:.045, respectively). Direct microscopic examinations revealed positive changes in desquamation, oedema, inflammation and vasocongestion scores in Group 3 compared to Group 2 (p:.007, p:.008, p:.007 and p:.006, respectively). Dexmedetomidine has a protective effect against ischaemia-reperfusion injury in penile tissue.     

Preventive effects of perioperative parecoxib on post-discectomy pain

BACKGROUND: Cyclooxygenase inhibitor treatment is viewed increasingly critical because of safety considerations, and there are several open questions on their optimal use. METHODS: In a randomized placebo-controlled study in 320 patients undergoing discectomy, we administered parecoxib 40 mg either perioperatively (before operation and after operation), after operation (first dose given in the evening after surgery), or before operation (single parecoxib dose given 45 min before surgery). We measured the main outcome variables: average pain score, morphine consumption, and opioid-related symptom distress at 25, 49, and 73 h after surgery. RESULTS: Perioperative parecoxib significantly (i) improved the pain score compared with both placebo and postoperative parecoxib, (ii) decreased morphine consumption, and (iii) reduced the opioid-related symptom distress score. Neither a single preoperative dose nor postoperative parecoxib (first dose given in the evening after surgery) significantly improved morphine's analgesic effectiveness. CONCLUSIONS: Perioperative parecoxib compared with postoperative parecoxib improves post-discectomy pain and results in a reduction in adverse effects associated with opioid therapy. Postoperative parecoxib, or a single pre-incisional parecoxib dose, does not significantly improve post-discectomy pain or opioid side-effects up to 3 days after surgery.     

Effects of delta-opioid receptor stimulation and inhibition on hippocampal survival in a rat model of forebrain ischaemia

Background: It has been reported that delta-opioid (DOP) receptor agonistsmay be neuroprotective in the central nervous system. However,the DOP agonist [D-Ala², D-Leu⁵]enkephalin (DADLE) does notproduce neuroprotection in severe forebrain ischaemia. The aimof this study was to examine the effects of DADLE on hippocampalneurone survival against less severe forebrain ischaemia. Methods: Intraperitoneal injection of DADLE (0 or16 mg kg^–1) inmale Sprague–Dawley rats was performed 30 min before ischaemia.Severe (10 min), moderate (8 min), or mild (6 min) forebrainischaemia was produced by bilateral carotid occlusion combinedwith hypotension (35 mm Hg) under isoflurane (1.5%) anaesthesia.Naltrindole (10 mg kg^–1) (DOP antagonist) was administered30 min before DADLE in order to confirm DOP receptor activationin the neuroprotective efficacy of DADLE. Naltrindole alonewas also administered 30 min before ischaemia to examine endogenousDOP agonism as a self-protecting mechanism against ischaemia.All animals were evaluated neurologically and histologicallyafter a 1 week recovery period. Results: DADLE improved neurone survival in hippocampal CA3 and dentategyrus (DG) sectors. CA1 neurones were not protected againstmoderate and mild ischaemia. Naltrindole abolished DADLE neuroprotectionin the CA3 and DG after both moderate and mild ischaemia. Interestingly,regardless of co-administration of DADLE, naltrindole significantlyworsened neuronal injury in the CA1 region after mild ischaemia. Conculsions: These results suggest that DADLE provides limited neuroprotectionto relatively ischaemia-resistant regions but not to selectivelyvulnerable regions. This was probably mediated by DOP stimulation.Pre-ischaemic treatment with a DOP antagonist, regardless ofco-administration of DADLE, worsened neuronal damage at theselectively vulnerable regions only after mild forebrain ischaemia.These data suggest that DOP activation with endogenous DOP ligandmay be involved in self-protecting ischaemia-sensitive regionsof the brain.     

Intrathecal morphine and clonidine for coronary artery bypass grafting

Background. After cardiac surgery adequate postoperative analgesiais necessary. We assessed analgesia using intrathecal morphineand clonidine. Methods. In a double-blind randomized study, 45 patients havingcoronary artery bypass graft surgery were allocated randomlyto receive i.v. patient-controlled analgesia (PCA) morphine(bolus, 1 mg; lock-out interval, 7 min) (control group), eitheralone or combined with intrathecal morphine 4 µg kg^–1or with both intrathecal morphine 4 µg kg^–1and clonidine 1 µg kg^–1. Intrathecal injectionswere performed before the induction of general anaesthesia.Pain was measured after surgery using a visual analogue scale(VAS). We recorded i.v. PCA morphine consumption during the24 h after operation. Results. Morphine dosage [median (25th–75th percentiles)]was less in the first 24 h in the patients who were given intrathecalmorphine + clonidine [7 (0–37) mg] than in other patients[40.5 (15–61.5) mg in the intrathecal morphine group and37 (30.5–51) mg in the i.v. morphine group]. VAS scoreswere lower after intrathecal morphine + clonidine compared withthe control group. Time to extubation was less after intrathecalmorphine + clonidine compared with the i.v. morphine group [225(195–330) vs 330 (300–360) min, P<0.05]. Conclusion. Intrathecal morphine and clonidine provide effectiveanalgesia after coronary artery bypass graft surgery and allowearlier extubation. Br J Anaesth 2003; 90: 300–3     

Analgesic effects of parecoxib following total abdominal hysterectomy

Background. Forty-eight ASA I–II patients undergoing totalabdominal hysterectomy (TAH) were studied in a double blind,randomized placebo controlled trial of parecoxib for postoperativeanalgesia. Methods. All patients were given propofol 2–4 mg kg^–1i.v., a non-depolarizing muscle relaxant, morphine 10 mg i.v.and prochlorperazine 12.5 mg i.m. intraoperatively. Their lungswere ventilated with nitrous oxide and isoflurane 1–1.5%in oxygen. Morphine was self-administered for postoperativeanalgesia via a patient controlled analgesia (PCA) device. Patientswere allocated randomly to receive either parecoxib 40 mg i.v.or normal saline on induction of anaesthesia. Results. Twelve patients did not complete the study. Of theremaining 36 patients, there was no significant difference betweenthe treatment groups in age, weight, ASA status, duration ofsurgery, or intraoperative dose of morphine. However, mean (95%CI) 24 h morphine consumption of 54 (42–65) mg in theparecoxib group was significantly (P=0.04) lower than that of72 (58–86) mg in the placebo group. Pain intensity scoreson sitting up were significantly lower (P=0.02) in the parecoxibgroup compared with placebo. There was no significant differencebetween the treatment groups in pain intensity scores at restand on deep inspiration, or in nausea, total number of vomitingepisodes, median number of rescue antiemetic doses, and sedationscores. Conclusions. Parecoxib 40 mg i.v. may be recommended in patientshaving TAH as it provides morphine-sparing analgesia. Br J Anaesth 2003; 90: 746–9     

吗啡对大鼠心肌缺血/再灌注损伤的保护作用

目的 探讨吗啡对离体大鼠心肌缺血/再灌注损伤的保护作用和机制。方法 建立离体大鼠心脏灌注模型。TTC染色梗死心肌。观察缺血/再灌注后,吗啡对冠脉流量（CF）、心率（HR）、左室压力（LVP）、左室压力最大变化速率（LVP/dtmax）及心梗范围的影响,并观察纳洛酮和glibenclamide对吗啡作用的影响。结果 缺血/再灌注后,离体大鼠心脏的CF、HR、LVP和LVP/dtmax显著下降（P<0.01）。缺血前给予吗啡可以使缺血/再灌注后HR、LVP和LVP/dtmax显著恢复（P<0.01）,心梗范围显著缩小（P<0.01）。吗啡不能增加缺血/再灌注后离体大鼠心脏的CF（P>0.05）。分别给予纳洛酮和glibenclamide可以完全取消吗啡的心肌保护作用。结论 吗啡可以减轻大鼠心肌的缺血/再灌注损伤。吗啡是通过心肌局部的阿片受体及心肌细胞的KATP通道介导产生心肌保护作用。     

A comparison of hypnotic and analgesic based sedation in a general intensive care unit

Background. Sedation of the critically ill patient has severalcomponents including hypnosis and analgesia. Hypnotic-basedsedation (HBS), where midazolam and/or propofol are used, withmorphine or another analgesic added as needed has been common.The advent of remifentanil has allowed greater use of analgesia-basedsedation (ABS) where relief of discomfort from the trachealtube or pain are the important objectives, and hypnosis is givenas necessary. Method. We compared HBS and ABS (remifentanil-based sedation)within a general intensive care unit (ICU). During the firststudy period of 12 weeks, 111 patients received HBS. After thedevelopment of new guidelines for the use of remifentanil inthe ICU, a second 12 week study period used an analgesia-basedregimen, with hypnotics added only if needed. Results. Ninety-six patients received ABS, and 79 received remifentanil.It was possible to manage 29 (37%) of the patients receivingremifentanil without the use of supplementary hypnotic agents.In the remaining 63% the use of remifentanil was associatedwith a reduction in the amount and duration of propofol used.Significantly more patients receiving ABS had satisfactory levelsof sedation during synchronized intermittent mandatory ventilation(19 [2,55] vs 50 [14,83], P<0.001). Conclusions. The use of ABS allowed patients to be managed morecomfortably, either without a hypnotic drug or with less hypnoticdrug, than using conventional HBS. Declaration of interest. M. Lane and P. Bassett were supportedby an educational grant from Glaxo Smith Kline PLC. The remifentanilwas donated by Elan Pharmaceuticals Ltd.     

Comparison between pentazocine, pethidine and placebo in the treatment of post-anesthetic shivering

BACKGROUND: We have compared the effects of pethidine, pentazocine and placebo in the treatment of post-anesthetic shivering. METHODS: Forty-five patients who shivered after routine surgery were allocated randomly to receive normal saline (n=15), pentazocine 7.5 mg (n=15) or pethidine 17.5 mg (n=15). RESULTS: After 10 min, 13 patients had stopped shivering in the pethidine group, which was significantly more than the incidence in the two other groups (placebo=2; pentazocine=4) (P<0.01). Pentazocine was not significantly different from normal saline in affecting shivering. CONCLUSION: We conclude that pentazocine 7.5 mg was not effective in the treatment of post-anesthetic shivering.