Ephedrine, dopamine, or doubtamine to treat hypotension with propofol during epidural anesthesia

PURPOSE: To compare the efficacy of ephedrine, dopamine and dobutamine for circulatory support during thoracic epidural anesthesia after anesthetic induction with propofol. METHODS: Forty patients undergoing lobectomy or mastectomy were divided into four groups of 10: a control group received no vasopressor; an ephedrine group received 5 mg ephedrine when the mean arterial pressure (MAP), measured every 2.5 min, decreased by 10% from baseline; dopamine and dobutamine groups received 5 microg x kg(-1) x min(-1) dopamine or 3 microg x kg(-1) x min(-1) dobutamine from five minutes after epidural injection of local anesthetic to the end of tracheal intubation. Anesthesia was induced with 2 mg x kg(-1) propofol. The MAP and heart rate (HR) were measured at baseline, 20 min after epidural injection, three minutes after propofol, and one minute after tracheal intubation. RESULTS: In the control group, MAP and HR decreased from 86+/-9 mmHg, 74+/-8 bpm to 62+/-9 mm Hg; P<0.0001, 60+/-8 bpm; P = 0.0003 after propofol. After tracheal intubation, MAP was restored to (81+/-13 mmHg, 70+/-13 bpm). In the ephedrine, dopamine, and dobutamine groups, MAP and HR remained unchanged during epidural anesthesia and propofol induction. However, after tracheal intubation, MAP and HR increased in the ephedrine (104+/-11 mm Hg; P = 0.004, 87+/-11 bpm; P<0.0001) and dobutamine (117+/-13 mm Hg; P = 0.0005, 100+/-11 bpm; P<0.0001) groups, but not in the dopamine group compared with baseline. CONCLUSION: Dopamine is preferable to ephedrine and dobutamine in providing hemodynamic stability during propofol induction and tracheal intubation following epidural anesthesia.     

Haemodynamic effects of induction of general anaesthesia with propofol during epidural anaesthesia

PURPOSE: To clarify whether propofol administration during thoracic or lumbar epidural anaesthesia intensifies the haemodynamic depression associated with epidural anaesthesia. METHODS: Patients (n = 45) undergoing procedures of similar magnitude were randomly divided into three study groups: a control group (n = 15) receiving general anaesthesia alone and two study groups undergoing thoracic (n = 15) and lumbar epidural anaesthesia (n = 15) before induction of general anaesthesia. All patients received 2 mg.kg-1 propofol at a rate of 200 mg.min-1, followed by a continuous infusion of 4 mg.kg-1.hr-1. Mean arterial blood pressure (MAP) and heart rate (HR) were measured at baseline, three minutes after induction, and one minute after tracheal intubation in all three groups and at 20 min after epidural anaesthesia was established in the thoracic and lumbar groups. RESULTS: Following epidural anaesthesia, MAP decreased from 94 +/- 14 (SD) at baseline to 75 +/- 11 mmHg (P < 0.0001) in the thoracic group and from 92 +/- 12 to 83 +/- 15 mmHg in the lumbar group. After propofol administration, MAP decreased further in the thoracic group to 63 +/- 9 mmHg (P = 0.0077) and to 67 +/- 10 mmHg (P = 0.0076) in the lumbar group. The MAP following propofol induction in the thoracic group (P < 0.0001) and in the lumbar group (P = 0.0001) was lower than MAP in the control group (81 +/- 9 mmHg). HR decreased only in response to thoracic epidural anaesthesia (P = 0.0066). CONCLUSION: The hypotensive effects of propofol are additive to those of epidural anaesthesia, resulting in a profound decrease in mean arterial pressure.     

A comparison of physiological responses to percussive brain trauma in dogs and sheep

Physiological variables were monitored in dogs and sheep after exposure of the brain to a pressure wave produced by a fluid-percussion device. Mean systemic arterial pressure (SAP), mean pulmonary arterial pressure (PAP), and pulmonary wedge pressure (PWP) were recorded prior to and following trauma. Lung lymph flows (QLYM) were measured prior to and for 2 hours after trauma. Plasma catecholamine levels were quantitated prior to and at 30 seconds following trauma. In 16 dogs, SAP increased from 123 +/- 14.6 to 254 +/- 60.8 mm Hg (p less than 0.0001), PAP increased from 17 +/- 4.4 to 27 +/- 10.8 mm Hg (p less than 0.05), and PWP increased from 4 +/- 2.4 to 15 +/- 8.8 mm Hg (p less than 0.0001), all at 30 seconds posttrauma. All pressures returned to near baseline values within 6 minutes. The QLYM from the right lymph duct in 12 dogs increased from 0.82 +/- 0.77 to 2.7 +/- 2.1 and 1.88 +/- 1.82 ml/30 min, respectively, at 30 and 120 minutes. In five dogs the plasma concentrations of dopamine, epinephrine, and norepinephrine increased from 234 +/- 98 to 1906 +/- 1384, 609 +/- 641 to 19,813 +/- 10,234, and 388 +/- 194 to 3223 +/- 992 pg/ml, respectively (all p less than 0.01). In sheep there were no changes in SAP, PAP, PWP, QLYM, or catecholamine levels in response to percussive wave trauma up to 10 atm. Ratios of lung tissue water to dry weight were not significantly different from control animals in either species. The authors conclude that in dogs there is a profound sympathetic discharge resulting in dramatic elevations in plasma catecholamines, systemic and pulmonary artery hypertension, and an increase in pulmonary lymph flow. Sheep fail to demonstrate changes in any of these variables after severe percussive wave brain trauma.     

喉罩与气管插管在全麻或复合硬膜外阻滞时的心率和血压改变

目的比较喉罩与气管插管用于全麻或全麻复合硬膜外阻滞患者的HR和BP变化.方法妇科手术80例,随机分为全麻气管插管(T)组、全麻喉罩(L)组、硬膜外阻滞 全麻气管插管(ET)组、硬膜外阻滞 全麻喉罩(EL)组,每组20例.硬膜外阻滞用1%利多卡因 0.15%丁卡因.全麻诱导咪唑安定2 mg、芬太尼0.2 mg、丙泊酚1.5 mg/kg、琥珀胆碱1.5 mg/kg后插气管导管或喉罩.全麻维持50%N2O O2 异氟醚,静注阿曲库铵、芬太尼.于麻醉前(基础,入室静卧10 min后)、插管后1 min、切皮、进腹探查后5 min、拔管后1 min记录MAP、SpO2、HR、PETCO2.结果插管时HR和MAP均低于基础值,而两组喉罩HR低于插气管导管者,硬膜外复合全麻喉罩组MAP低于气管插管组.切皮时两组全麻MAP高于复合硬膜外组.探查时两组复合硬膜外者HR和MAP均低于基础值,且MAP低于单纯全麻者(P＜0.05).拔管时各组HR均显著高于基础值,MAP未复合硬膜外者显著高于基础值.结论(1)插喉罩对BP和HR的影响不如气管导管剧烈;(2)复合硬膜外阻滞时气管插管或喉罩置入应激反应轻,也可减轻探查时的BP波动.     

Esmolol for control of increases in heart rate and blood pressure during tracheal intubation after thiopentone and succinylcholine

Esmolol, an ultra-short-acting cardioselective beta-adrenergic blocker, was investigated in a double-blind prospective protocol for its ability to control haemodynamic responses associated with tracheal intubation after thiopentone and succinylcholine. Thirty ASA physical status I patients received a 12-minute infusion of esmolol (500 micrograms X kg-1 X min-1 for four minutes, then 300 micrograms X kg-1 X min-1 for 8 minutes) or saline. Five minutes after the start of the drug/placebo infusion, anaesthesia was induced with 4 mg X kg-1 thiopentone followed by succinylcholine for tracheal intubation. Prior to induction esmolol produced significant decreases in heart rate (HR) (9.3 +/- 1.8 per cent) and rate-pressure product (RPP) (13.1 +/- 1.8 per cent), systolic blood pressure (SAP) (4.3 +/- 1.5 per cent) and mean arterial blood pressure (MAP) (1.7 +/- 2.0 per cent). Increases in HR, SAP and RPP after intubation were approximately 50 per cent less in patients given esmolol compared to patients given placebo. There were highly significant differences in HR (p less than 0.0001), and RPP (p less than 0.0005) and significant differences in SAP (p less than 0.05) when the maximal esmolol post-intubation response was compared to the maximal placebo response. Infusion of esmolol in the dose utilized in this study significantly attenuated but did not completely eliminate cardiovascular responses to intubation.     

Cuff-occluded rate of rise of peripheral venous pressure: a new, highly sensitive technique for monitoring blood volume status during hemorrhage and resuscitation

We investigated the cuff-occluded rate of rise of peripheral venous pressure (CORRP)--a new, nearly noninvasive peripheral hemodynamic monitoring parameter--in dogs subjected to hemorrhage and resuscitation. Twelve adult mongrel dogs under general anesthesia were subjected to hemorrhage of 30% of their estimated total blood volume (TBV) for 30 minutes; after this time the extracted blood was reinfused. Arterial pressure (AP), central venous pressure (CVP), pulmonary arterial pressure (PAP), cardiac output (CO), pulmonary venous pressure (PWP), heart rate, and CORRP were continuously monitored. A "clinically significant change" (CSC) in CORRP and CO was defined as a change that exceeded two standard deviations from the mean of five baseline measurements made before the onset of hemorrhage, whereas a CSC in PWP or CVP was conservatively defined as a change that exceeded 2 mm Hg from the average of five baseline measurements, and a CSC in PAP and AP was defined as a change that exceeded 3 mm Hg and 5 mm Hg, respectively from the average of the baseline measurements. There was no consistent change in heart rate during hemorrhage. Thus defined, a CSC in CORRP occurred after an average extraction of 9.2% +/- 4.7% TBV, whereas a CSC was not seen until an average loss of 16.5% +/- 8.1% TBV for AP, 21% +/- 13% TBV for PWP, 15.5% +/- 7% TBV for PAP, and 35% +/- 3% TBV for CVP. These average blood losses are all significantly different from the average blood loss required to effect a CSC in CORRP. The blood loss required to effect a CSC in CO averaged 9.7% +/- 6%. We conclude that in these anesthetized dogs, CORRP detected blood loss earlier than other commonly used hemodynamic parameters, including several invasive parameters such as CVP, PAP, and PWP; CORRP and CO were equivalent in their ability to detect early stages of blood loss.     

Laparoscopic approach to pheochromocytoma: is a lower intraabdominal pressure helpful?

Laparoscopic adrenalectomy is gaining popularity because of its well-documented benefits. The aim of our study was to see if a decreased intraoperative intraabdominal pressure during laparoscopic adrenalectomy would affect the hemodynamic variables and the serum levels of catecholamines. We randomly divided 9 patients into 2 groups, maintaining either an intraabdominal pressure of 15 mm Hg (group A) or 8-10 mm Hg (group B). Norepinephrine and epinephrine blood levels were measured preoperatively, during endotracheal intubation, carboperitoneum, surgical manipulation of tumor just before the ligation of the adrenal vein, and tracheal extubation; the hemodynamic variables were recorded. The introduction of carboperitoneum resulted in an increase in heart rate and mean arterial blood pressure (MAP), although it was statistically insignificant. The norepinephrine levels showed a statistically significant increase in group A as compared with group B (P = 0.0002). Surgical manipulation of the tumor resulted in a significant increase in MAP and norepinephrine levels in group A (P = 0.007 and P = 0.0001, respectively). The epinephrine levels did not change as much because the tumor was probably predominantly norepinephrine-secreting. Norepinephrine levels continued to be high even during tracheal extubation in group A patients (P = 0.027). We conclude that a low intraabdominal pressure of 8-10 mm Hg causes less catecholamine release and fewer hemodynamic fluctuations.     

The preoperative and intraoperative hemodynamic predictors of postoperative myocardial infarction or ischemia in patients undergoing noncardiac surgery.

Among hypertensive and diabetic patients undergoing elective noncardiac surgery, preoperative status and intraoperative changes in mean arterial pressure (MAP) were evaluated as predictors of postoperative ischemic complications. Of 254 patients evaluated before operation and monitored during operation, 30 (12%) had postoperative cardiac death, ischemia, or infarction. Twenty-four per cent of patients with a previous myocardial infarction or cardiomegaly had an ischemic postoperative cardiac complication. Only 7% of those without either of these conditions sustained an ischemic complication. No other preoperative characteristics, including the presence of angina, predicted ischemic cardiac risk. Nineteen per cent of patients who had 20 mm Hg or more intraoperative decreases in MAP lasting 60 minutes or more had ischemic cardiac complications. Patients who had more than 20 mm Hg decreases in MAP lasting 5 to 59 minutes and more than 20 mm Hg increases lasting 15 minutes or more also had increased complications (p less than 0.03). Changes in pulse were not independent predictors of complications and the use of the rate-pressure product did not improve prediction based on MAP alone. In conclusion patients with a previous infarction or radiographic cardiomegaly are at high risk for postoperative ischemic complications. Prolonged intraoperative increases or decreases of 20 mm or more in MAP also resulted in a significant increase in these potentially life-threatening surgical complications.     

STUDIES OF ANAESTHESIA IN RELATION TO HYPERTENSION IH: PULMONARY GAS EXCHANGE DURING SPONTANEOUS VENTILATION

Ventilation, pulmonary gas exchanges and oxygen transport werestudied in a group of treated and untreated hypertensive elderlypatients, before, during and after nitrous oxide-halothane anaesthesiawith spontaneous ventilation. During anaesthesia minute andalveolar ventilation were depressed (— 30 per cent) outof proportion to the decrease in oxygen uptake (-18 per cent)and carbon dioxide production (— 19 per cent), and moderatehypercapnia ensued (mean Paoo3 50.3 mm Hg). All these variablesreturned to the pre-anaesthetic levels within 1 hour of terminatinganaesthesia. VD/VT was increased following induction of anaesthesiaas a result of decreased tidal volumes (— 47 per cent),but did not change progressively during the course of anaesthesia.Total deadspace (VD) was reduced by an average of 44 ml as aresult of intubation. Based on measurements of arterial Poaand the alveolar-arterial Poj difference, mean pulmonary venousadmixture was 10.4 per cent before anaesthesia, 10.9 per centduring anaesthesia but before surgery, 13.1 per cent after surgery,and 15.6 per cent 1 hour after the termination of anaesthesia.Although the average postoperative arterial Poa was slightlylower ( - 7.4 rnm Hg) than before anaesthesia, the differencewas due to many factors, and no evidence of a deteriorationin the over-all pulmonary gas exchange could be found. The conceptof "airway closure" in the supine elderly subject as a causefor the increased pulmonary venous admixture at rest is discussed.Impairment of pulmonary function during anaesthesia in hypertensiveelderly patients causes less concern than the severe changesin cardiovascular function ^*Present address: Hospital Notre Dame, Montreal133, P.Q., Canada     

The effect of sufentanil on the cardiovascular responses to tracheal intubation

The effects of sufentanil 0.5 or 1 microgram/kg, given intravenously after induction of anaesthesia, on the cardiovascular responses to tracheal intubation were examined in a controlled, randomised, double-blind investigation. The control group of patients exhibited significant rises in arterial blood pressure and heart rate for 4 minutes after tracheal intubation. Heart rate exceeded 100 beats/minute and systolic pressure increased by over 20% in every patient. All patients moved or breathed within 10 minutes of the administration of suxamethonium. Sufentanil 0.5 microgram/kg prevented increases in the mean values of heart rate and arterial blood pressure, although increases were observed in five patients. Significant falls in the mean values of heart rate and arterial pressure occurred from 4 minutes after intubation until observations ended 15 minutes after induction of anaesthesia. Two patients moved or breathed during this time, although movement in response to nerve stimulation occurred in all patients 10 minutes after administration of suxamethonium. Sufentanil 1 microgram/kg was effective in suppressing a rise in heart rate or arterial pressure in every patient. Significant falls in these variables occurred from 2 minutes after tracheal intubation onwards. No patient moved or breathed for 15 minutes after induction of anaesthesia, although neuromuscular transmission was present 10 minutes after giving suxamethonium in each case.     

喉面罩对老年高血压患者腹腔镜手术应激反应的影响

目的:比较麻醉喉面罩与气管插管对老年高血压患者腹腔镜胆囊切除术(laparoscopic cholecystectomy,LC)围术期应激反应的影响。方法:择期老年高血压患者行LC 60例,ASAⅠ~Ⅱ级,随机分成喉面罩组(A组)和导管组(B组),通气设置:潮气量(VT)6~8 ml/kg,频率16~18/min,间歇正压通气(IPPV),呼吸末正压3cm H2O,CO2气腹(压力<12mm Hg),保持PETCO218~22.5mm Hg。记录两组在麻醉诱导前、插管后5min、气腹后、拔管前、拔管后5min 5个时点的心率(HR),心率与收缩压乘积(RPP),血糖,皮质醇拔管时呛咳发生率等指标。结果:气腹对两组循环有明显的增强作用,心率与收缩压乘积较气腹前明显升高(P<0.05)。两组血糖自插管后均不同程度的上升,B组于插管后上升更明显,与A组比较差异有统计学意义(P<0.05);两组术毕时皮质醇水平均明显上升(P<0.05),B组拔管后继续上升;A组拔管时呛咳发生率低。结论:老年高血压患者使用喉面罩,在12mm Hg CO2气腹压力下,不会影响肺通气效果,应激反应轻,心肌耗氧少,血液动力学稳定,术毕对喉面罩反应轻,耐受时间延长有利于辅助通气,拔管后通气改善更好。但应尽量减少气腹压力,气腹后、间歇正压通气期间应设一定呼吸末正压,可适当增加呼吸频率,避免发生高CO2血症。     

Myocardial metabolism and haemodynamic responses with enflurane anaesthesia for coronary artery surgery

Ten patients were studied before, during and after enflurane anaesthesia for coronary vein grafting. All had good ventricular function and nine were receiving effective beta blockade. Cardiac output and vascular pressures were measured, plus coronary sinus blood flow (CBF), myocardial oxygen consumption (MVO2) and lactate extraction (MLE). Enflurane induction (10 minutes, mean 1.72 per cent end tidal) reduced blood pressure (MAP), due to decreased cardiac index (CI), with no change in heart rate or systemic resistance. Intubation returned MAP and CI to control level but the heart rate increased. Subsequently, enflurane kept MAP, CI and stroke work below the awake level. CBF decreased on induction, rose again on intubation and remained normal before bypass. MVO2 fell on induction from an increase in CS oxygen content, which remained elevated. Normal MLE continued in every patient. There was no evidence of myocardial ischaemia in patients on beta blockade, when haemodynamics were maintained at or below those of the sedated, awake state.     

Nifedipine attenuates the hypertensive response to tracheal intubation in pregnancy-induced hypertension

Thirty women with pregnancy-induced hypertension (PIH) scheduled for Caesarean section under general anaesthesia were studied to evaluate the efficacy of sublingual nifedipine in attenuating the pressor response to laryngoscopy and tracheal intubation. The patients were randomly given either the contents of a nifedipine capsule 10 mg or placebo sublingually 20 min before induction of anaesthesia. Blood pressure and heart rate were recorded at various time intervals. There was a decrease in mean arterial blood pressure (MAP) after pre-treatment with nifedipine (P < 0.01). The increase in MAP during laryngoscopy and intubation was higher in the control group compared with nifedipine pretreatment group (P < 0.01). During laryngoscopy and intubation, MAP decreased by 3 mmHg in the nifedipine pretreatment group, while there was an increase of 14 mmHg in the control group. Heart rate increased in both the groups during the laryngoscopy and tracheal intubation (P < 0.01) but the increase was higher in the nifedipine group than in the control group (P <0.05). Neonatal Apgar scores in both the groups were comparable. These results suggest that sublingual nifedipine is effective in attenuating the hypertensive response to laryngoscopy and intubation but not the tachycardiac response in parturients with PIH.     

Hemodynamic effects of the induction of general anesthesia after low thoracic epidural anesthesia

Sixteen ASA 1 or 2 patients scheduled for abdominal surgery were included in the study after they had given their informed consent. Thirty minutes after starting a low-thoracic epidural anaesthesia (median level of sensitivity loss: T5), the patients were randomly given an intravenous bolus injection of either thiopentone (4 mg.kg-1, n = 8) or etomidate (0.5 mg.-1, n = 8), associated with succinylcholine 1 mg.kg-1. One minute after induction of general anaesthesia, the patients were intubated and mechanically ventilated (V(T) 8 ml.kg-1, rate 12 c.min-1). Mean arterial blood pressure (MAP) (oscillometric method), cardiac output (CO) (transthoracic bioimpedance) and heart rate were recorded semi-continuously. Total peripheral resistances (TPR) were calculated using the formula TPR = (MA/CO)*80. There were no differences between the groups in patient age, height, weight, and cardiovascular consequences of epidural anaesthesia. After anaesthetic induction and before endotracheal intubation, there was a slight decrease in CO in both groups, without any change in MAP. After intubation, MAP increased in both groups through peripheral vasoconstriction, whereas CO did not increase further. A significant tachycardia was occurred only seen in the thiopentone group, before and after tracheal intubation. This study showed that thiopentone and etomidate were suitable drugs for anaesthetic induction in a patient under epidural blockade. However, the absence of tachycardia following etomidate may be beneficial in cardiac patients. The monitoring of cardiac output determinants during thiopentone and etomidate anaesthesia require further invasive investigations.     

Bolus dose remifentanil for control of haemodynamic response to tracheal intubation during rapid sequence induction of anaesthesia

The effect of three bolus doses of remifentanil on the pressor response to laryngoscopy and tracheal intubation during rapid sequence induction of anaesthesia was assessed in a randomized, double-blind, placebo- controlled study in four groups of 20 patients each. After preoxygenation, anaesthesia was induced with thiopental 5-7 mg kg-1 followed immediately by saline (placebo) or remifentanil 0.5, 1.0 or 1.25 micrograms kg-1 given as a bolus over 30 s. Cricoid pressure was applied just after loss of consciousness. Succinylcholine 1 mg kg-1 was given for neuromuscular block. Laryngoscopy and tracheal intubation were performed 1 min later. Arterial pressure and heart rate were recorded at intervals until 5 min after intubation. Remifentanil 0.5 microgram kg-1 was ineffective in controlling the increase in heart rate and arterial pressure after intubation but the 1.0 and 1.25 micrograms kg-1 doses were effective in controlling the response. The use of the 1.25 micrograms kg-1 dose was however, associated with a decrease in systolic arterial pressure to less than 90 mm Hg in seven of 20 patients.      

General versus epidural anesthesia for femoral-popliteal bypass surgery

This study examines whether epidural anesthesia is more effective than general anesthesia using an inhalation agent in controlling cardiovascular responses during femoral-popliteal bypass surgery. Nineteen patients were randomized into two groups: general anesthesia (n = 10) and epidural anesthesia (n = 9). The patients who underwent general anesthesia received sodium pentothal and succinylcholine for induction of anesthesia and 60% N2O, 40% O2, and 1% to 1.5% isoflurane for maintenance. Fifteen minutes before extubation, the patients received morphine sulfate 0.05 mg/kg intravenously (IV). The group that underwent epidural anesthesia received anesthesia to T-10 (through a catheter placed in the L4-5 interspace using 3% 2-chloroprocaine). Thirty minutes after the last dose, 0.05 mg/kg IV was administered. Hemodynamic variables were recorded at selected intervals during the operation and for 60 minutes in the recovery room. In the general anesthesia group, mean arterial pressure (MAP) and rate pressure product (RPP) significantly decreased (p less than 0.05) during the operation as compared with preoperative values. Following intubation and skin incision, 5 minutes after extubation, and after 60 minutes in the recovery room, MAP, heart rate (HR), and RPP were significantly greater (p less than 0.05) as compared with intraoperative periods. In the epidural anesthesia group, there were clinically important decreases in MAP and RPP after reaching T-10 and skin incision. The general anesthesia patients showed higher MAP, HR, and RPP 5 minutes after extubation and after 60 minutes in the recovery room. Epidural anesthesia patients showed stable hemodynamic patterns throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thoracolumbar epidural anaesthesia blocks the circulatory response to laryngoscopy and intubation

Laryngoscopy and endotracheal intubation cause a stress reaction resulting in an increase in heart rate and systemic blood pressure. This haemodynamic response is considered to be due to a sympathetic discharge caused by stimulation of the upper respiratory tract. This stress reaction during laryngoscopy and endotracheal intubation was studied in patients with total thoracolumbar epidural anaesthesia (EDA). Nine patients with thoracolumbar EDA including at least the segments T1 to L2 were compared to seven patients without EDA during induction of general anaesthesia. The epidural anaesthesia was achieved with 2% mepivacaine with adrenaline. General anaesthesia was induced with thiopentone 4-5 mg/kg followed by 100 mg suxamethonium. The highest blood pressure value during the first 2 min after intubation was compared to the value immediately before intubation. The epidural anaesthesia caused a reduction of the mean arterial blood pressure (MAP) by 25%, and a reduction of the heart rate (HR) by 7%, but neither the induction with thiopentone nor the laryngoscopy and intubation caused any changes in mean arterial blood pressure or heart rate. However, in the control group MAP increased 29% and HR 16% following intubation. Thus, the T1-L2 epidural anaesthesia with 2% mepivacaine with adrenaline blocked the blood pressure reaction to laryngoscopy and intubation, and consequently the efferent sympathetic nervous system was completely blocked.     

Airtraq(R)喉镜和Macintosh直接喉镜在经口气管插管时血流动力学的比较

目的比较Airtraq(R)视频喉镜和Macintosh直接喉镜经口气管插管时心血管反应。方法40例拟择期经口气管插管全麻下手术的患者,按照随机数字表随机分为两组,Airtraq(R)组（A组）和Macintosh喉镜组（M组）,每组20例。观察麻醉诱导前、诱导后、插管即刻、插管后1、3 min时的心率(HR)、血压和...     

The bispectral index response to tracheal intubation is similar in normotensive and hypertensive patients

PURPOSE: To compare the hemodynamic and bispectral index (BIS) responses to tracheal intubation in normotensive and hypertensive patients. METHOD: Three minutes after induction of anesthesia with thiamylal and fentanyl, tracheal intubation was performed in 24 normotensive and 22 hypertensive patients. Heart rate (HR), mean arterial pressure (MAP), and BIS were measured every minute. RESULTS: Tracheal intubation increased HR, MAP, and BIS in both normotensive and hypertensive patients. The increase in MAP was significantly greater in hypertensive patients than in normotensive patients, but there were no differences in HR or BIS in the two groups of patients. CONCLUSION: Patients with and without hypertension exhibit the same arousal response (as measured by BIS) to tracheal intubation despite the enhanced vasopressor response in hypertensive patients.     

Comparison of the effects of succinylcholine and atracurium on intracranial pressure in monkeys with intracranial hypertension

The effects of succinylcholine (1.5 mg X kg-1 IV) administered five minutes after a defasciculating dose of curare (0.05 mg X kg-1 IV), were compared with the effects of atracurium (0.5 mg X kg-1 IV) on intracranial pressure (ICP) in 13 cynomolgus monkeys with intracranial hypertension (ICP approximately 25 mmHg). Neither succinylcholine nor atracurium increased ICP during general anaesthesia with 60 per cent N2O/O2, 0.5-1 per cent halothane. During a rapid sequence induction and intubation with thiopentone 5 mg X kg-1 IV, ICP increased equally with intubation following both atracurium (25 +/- 1 to 32 +/- 2 mmHg) and succinylcholine (25 +/- 1 to 31 +/- 2 mmHg) (p less than 0.05). Intubation was also associated with significant increases in PaCO2, CVP and MAP. We conclude that in this primate model of intracranial hypertension, neither atracurium nor succinylcholine (when given following a defasciculating dose of curare) elevates ICP. In terms of the elevation of ICP associated with intubation, atracurium was found to offer no advantage over succinylcholine.