Intratracheal intubation without muscle relaxant with the use of remifentanil-propofol]

OBJECTIVES: To assess tracheal intubation conditions after induction of anaesthesia with remifentanil and propofol, using itemized scoring criteria. STUDY DESIGN: Clinical, prospective, open, non comparative trial. PATIENTS: One hundred consecutive patients undergoing surgery not requiring muscle relaxation, during the study period extended over 12 months. METHODS: After premedication with lorazepam (2 mg) the day before and hydroxyzine (100 mg) one hour before surgery, anaesthesia was induced with remifentanil administered continuously with a syringe pump at a rate of 1.20 +/- 0.06 micrograms.kg-1.min-1 and propofol (3 mg.kg-1 IV bolus). The trachea was intubated two minutes later and mouth opening, glottis exposure, glottis opening, movements, additional anaesthetic agents and chest rigidity were recorded. RESULTS: Intubation conditions were excellent in 87% of patients, and the tube was inserted rapidly, within two minutes. However in 38% of patients the cuff inflation caused cough. In 13%, glottis opening was delayed and intubation required three minutes. A major decrease of arterial pressure and heart rate was recorded in 9 and 6% of patients respectively. CONCLUSION: Induction of anaesthesia using remifentanil and propofol allows satisfactory tracheal intubation without a muscle relaxant. However this technique is contraindicated: a) in patients with a full stomach, as intubation is not always successful at the first attempt; b) in patients scheduled to undergo neurosurgery or ophthalmic surgery, as tracheal intubation may elicit cough, increasing intra-cranial and intra-ocular pressure; c) in patients in poor circulatory status, as it decreases significantly arterial pressure and heart rate.     

Intravenous enalaprilat and autonomic reflexes

Thirty healthy patients, who were to undergo surgery which required tracheal intubation, were given an intravenous injection of enalaprilat (either 0.5 mg, 1 mg, 2 mg or 4 mg; six patients for each dose) or normal saline 17 minutes before induction of anaesthesia with thiopentone 3-5 mg/kg, and suxamethonium 1.5 mg/kg. Postural manoeuvres were performed 5 minutes before and 6, 11 and 16 minutes after enalaprilat or saline. Complete inhibition of angiotensin converting enzyme occurred with all doses of enalaprilat, which allowed the four different treatment groups to be considered as one large treated group. The mean arterial pressure was almost unchanged during the postural manoeuvres; the heart rate increased, mostly similarly (by approximately 10%) in both groups. Mean arterial pressure in the recumbent position decreased over the 17 minutes before induction in the enalaprilat group, and increased slightly in the control group (treated mean, -5.0%; controls mean, 1.8%; difference, -6.8%; 95% confidence intervals of difference, -2.3 to -11.3%, p less than 0.01). This difference was again seen after induction (treated, -8.0%; controls, 7.7%; confidence intervals of difference, -0.6 to -31%) and for a 5-minute period shortly after tracheal intubation. The increases in mean arterial pressure produced by intubation itself were similar in both groups (treated, + 36%; controls, + 35%; 95% confidence intervals of difference, -16% to + 18%). Changes in heart rate after induction were also similar in both groups. It is concluded that intravenous enalaprilat acted as a hypotensive agent with a sparing effect on autonomic reflexes, both before and after induction of anaesthesia.     

Attenuation of the pressor response to tracheal intubation with oral nitrendipine

The effect of nitrendipine on the cardiovascular responses to tracheal intubation was studied in a placebocontrolled, randomised, double–blind trial. Thirty patients (ASA physical status 1) undergoing elective surgery either 5 or 10 mg nitrendipine, or a placebo orally 3 h before induction of anaesthesia (n = 10 for each group). Anaesthesia was induced with sodium thiopentone 5 mg/kg i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg/kg i.v. Patients receiving the placebo showed a significant increase in the mean arterial pressure and the rate–pressure product in response to tracheal intubation. These increases following intubation were reduced in nitrendipine–treated patients compared with the placebo group (P < 0.05). Oral administration of nitrendipine (5 or 10 mg, 3 h before induction of anaesthesia) was able to attenuate the hypertensive response to tracheal intubation in ASA 1 patients under light anaesthesia. We propose this pharmacological technique with supplementary doses of opioids and/or benzodiazepines for the management of patients with hypertension or coronary artery disease.     

Lightwand intubation does not reduce the increase in intraocular pressure associated with tracheal intubation.

OBJECTIVE: To evaluate the changes in hemodynamic variables and intraocular pressure (IOP) after tracheal intubation using either lightwand or direct-vision laryngoscopy techniques. DESIGN: Prospective, randomized study. SETTING: Inpatient anesthesia at a University Anesthesia Department. PATIENTS: 50 normotensive, ASA physical status I and II patients, without ocular or cardiovascular diseases, and with a Mallampati score no greater than 2. INTERVENTIONS: After intravenous (i.v.) midazolam premedication (0.05 mg.kg-1), general anesthesia was induced with fentanyl (1 microgram.g-1) and thiopental sodium (5 mg.g-1) followed by vecuronium bromide (0.1 mg.g-1), then patients were randomly allocated to receive either the lightwand (Trachlight, n = 25) or direct-vision laryngoscopy (Laryngoscopy, n = 25) intubating techniques. General anesthesia was maintained with 1% isoflurane and 60% nitrous oxide in oxygen mixture for 5 minutes. MEASUREMENTS AND MAIN RESULTS: Baseline hemodynamic variables were recorded 10 minutes after i.v. premedication, and then every minute after tracheal intubation. Intraocular pressure measurements were performed by means of a computerized indentation tonometer after general anesthesia induction and then 1 and 5 minutes after tracheal intubation. In both groups, mean arterial blood pressure and heart rate increased from baseline, without differences between the two groups. One minute after intubation, IOP increased in both groups: the mean percentage increase was 32% in the Laryngoscopy group and 16% in the Trachlight group. However, this difference was not statistically significant. Five minutes after intubation, IOP decreased to baseline values in both groups. CONCLUSION: We conclude that in healthy patients without ocular disease, using a lightwand intubating technique does not reduce the hemodynamic responses and increase in IOP associated with tracheal intubation as compared with conventional direct-vision laryngoscopy.     

Atropine in the premedication of patients at risk. Its effect on hemodynamics and salivation during intubation anesthesia using succinylcholine]

Should atropine be administered for premedication? This question continues to be controversial; in particular, the combined administration of atropine and succinylcholine has been investigated with conflicting results by numerous researchers. The present study was carried out to assess the effect of premedication with atropine on hemodynamic variables and salivation in patients assigned to ASA class II and III. METHODS. Eighty ASA class II or III patients received pethidine 1.0 mg/kg and promethazine 0.5 mg/kg i.m. 30 min prior to induction of anesthesia and atropine, either 0.01 mg/kg i.v. 10 min or 0.01 mg/kg i.m. 30 min prior to a standardized anesthetic induction with alcuronium (precurarizing dose), thiopental, and succinylcholine. In the control groups (20 patients each), no atropine was given. Systolic, diastolic, and mean arterial pressures (MAP) were measured. The ECG was monitored for arrhythmias. Salivation was assessed semiquantitatively using swabs positioned within the pharyngeal space. RESULTS. Ten minutes after the administration of atropine i.v., a significant increase in heart rate (HR) was observed; this did not occur within 30 min after administration of atropine i.m. At the time of tracheal intubation, HR was significantly increased in both i.v. atropine risk groups. After atropine i.m., an increase in heart rate during intubation was observed in ASA class II patients only. No increase in heart rate occurred in the control groups during tracheal intubation. Neither i.m. nor i.v. atropine had any significant effect on blood pressure. Arrhythmias occurred in a few cases with both routes of administration; several instances of marked tachycardia were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of pre-operative metoprolol on cardiovascular and catecholamine response and bleeding during hysterectomy.

The effect of a pre-operative dose of metoprolol on the catecholamine and cardiovascular responses to tracheal intubation and surgery, cardiac complications and intra-operative blood loss, were studied in patients undergoing elective hysterectomy during general anaesthesia. The study was double-blind and placebo controlled. The patients received metoprolol 100 mg or placebo orally 1-25 h before anaesthesia. In patients given metoprolol, heart rate and mean arterial pressure were lower during the first 45 min of anaesthesia. Plasma adrenaline and noradrenaline concentrations increased in both groups in response to tracheal intubation and surgery, but were higher after metoprolol. The incidence of arrhythmias was less after metoprolol. The mean operative blood loss was greater in the placebo group (486 +/- 170 ml (SEM) compared to 231 +/- 43 ml (SEM) after metoprolol). We conclude that oral premedication with metoprolol attenuates the hypertensive response to tracheal intubation and reduces both arrhythmias and operative blood loss.     

Cardiovascular response to tracheal intubation in patients with intracranial tumor. Comparative study between urapidil and lidocaine

OBJECTIVES: To compare the effects of urapidil and lidocaine on cardiovascular response to laryngoscopy and tracheal intubation in patients with brain tumors. PATIENTS AND METHODS: Prospective, randomized double-blind study of 40 ASA II-III patients undergoing elective surgery for supratentorial tumor resection. The patients were assigned to two groups of 20 to receive an intravenous bolus of 1.5 mg/kg of lidocaine or 0.4 mg/kg urapidil before laryngoscopy and intubation. Anesthetic induction was performed with 0.03 mg/kg midazolam, 3 micrograms/kg of fentanyl, 5 mg/kg of thiopental and 0.2 mg/kg of vecuronium. Anesthesia was maintained with N2O/O2 (60%/40%) and isoflurane (0.5% expired). The following variables were recorded: mean blood pressure, heart rate and arterial oxygen saturation (SpO2) at baseline and 1, 2 and 3 min after induction and at 1, 2, 3, 4, 5 and 10 min after laryngoscopy and tracheal intubation. RESULTS: The two groups were comparable with respect to age, sex, weight, height and baseline hemodynamics. No statistically significant differences in hemodynamic variables were found between the two groups. Mean blood pressure in the postintubation period stayed near baseline and heart rate increased significantly after laryngoscopy and tracheal intubation in both groups. SpO2 decreased 7 min after administration of urapidil and stayed lower throughout the study period and was statistically different from SpO2 in the lidocaine group. All changes described were within clinically normal ranges. CONCLUSIONS: In patients undergoing neurosurgery to remove a supratentorial tumor, both lidocaine and urapidil reduce the pressor response to laryngoscopy and tracheal intubation at the doses given in this study. However, neither was able to prevent the increase in heart rate.     

Small doses of remifentanil or sufentanil for blunting cardiovascular changes induced by tracheal intubation: a double-blind comparison

BACKGROUND AND OBJECTIVE: To compare the effects on cardiovascular changes induced by tracheal intubation when small doses of either remifentanil or sufentanil are used in the presence of midazolam. METHODS: Thirty normotensive, ASA physical status I-II patients, receiving general anaesthesia for major abdominal surgery, received an intravenous midazolam premedication (0.05 mg kg-1) 10 min before induction. They were randomly allocated to receive in a double-blind fashion an intravenous bolus of either (a) remifentanil given as a bolus dose 1 microgram kg-1 (n = 15), or else (b) sufentanil 0.1 microgram kg-1 infused over 60 s (n = 15). In each instance this loading dose was followed by a continuous intravenous infusion (0.1 microgram kg-1 min-1 or 0.01 microgram kg-1 min-1 of remifentanil or sufentanil, respectively). General anaesthesia was induced with propofol (2 mg kg-1), followed by atracurium besilate (0.5 mg kg-1) to facilitate tracheal intubation. Following intubation, the lungs were mechanically ventilated with a 60% nitrous oxide in oxygen mixture and a 1% inspired sevoflurane. RESULTS: Arterial pressure and heart rate were recorded before induction of anaesthesia (baseline), immediately before intubation, immediately after tracheal intubation and every minute for the first five minutes thereafter. No differences in systolic and diastolic arterial pressures were observed between the two groups. At the end of the study period, systolic and diastolic pressures slightly decreased from preinduction values in both groups. Four patients in the remifentanil group (26%) and five patients in sufentanil group (33%) showed at least one systolic pressure value < 90 mmHg during the study period (P = not significant); however, the observed decreases in systolic pressure were transient and did not require treatment. Heart rate values were not affected by tracheal intubation in either group. CONCLUSIONS: In healthy normotensive patients without cardiovascular disease the use of a relatively small dose of either remifentanil or sufentanil after standard midazolam premedication results in a similar and clinically acceptable effectiveness in blunting the cardiovascular changes induced by tracheal intubation.     

Clinical comparison of either small doses of fentanyl or remifentanil for blunting cardiovascular changes induced by tracheal intubation

BACKGROUND: To compare in a prospective, randomized study the effects on cardiovascular changes after tracheal intubation produced by small doses of either remifentanil or fentanyl. METHODS: With Ethical Committee approval, after intravenous midazolam premedication (0.05 mg.kg-1), 30 normotensive, ASA physical status I-II patients, without cardiovascular or respiratory diseases, and with a Mallampati score < 2, were randomly allocated to receive an intravenous bolus of either 3 micrograms.kg-1 fentanyl (n = 15) or 1 microgram.kg-1 remifentanil (n = 15) infused over 60 sec and followed by a 0.15 microgram.kg-1.min-1 continuous intravenous infusion. General anesthesia was then induced with propofol (2 mg.kg-1), followed by atracurium besilate (0.5 mg.kg-1) to facilitate tracheal intubation. Following intubation, the lungs were ventilated mechanically using a 60% nitrous oxide in oxygen mixture with a 1% inspired fraction of sevoflurane. Arterial blood pressure and heart rate were recorded before anesthesia induction (baseline), one minute after induction of anesthesia, immediately after tracheal intubation and every minute for the first five minutes after intubation. RESULTS: Systolic arterial blood pressure values were significantly higher in the Fentanyl than in the Remifentanil group patients from 2 to 5 min after tracheal intubation (p < 0.01), while no differences were observed between the two groups in either diastolic arterial blood pressure or heart rate values. Four patients in the Remifentanil group (26%) but only one patient in the Fentanyl group (7%) showed systolic blood pressure values < 90 mmHg during the study period (p = not significant); however, the observed decreases in systolic arterial blood pressure values were transient and did not require treatment for any subject. CONCLUSION: We conclude that in healthy normotensive patients, the control of cardiovascular responses to tracheal intubation obtained with a 1 microgram.kg-1 loading dose of remifentanil is more effective than that provided by a 3 micrograms.kg-1 bolus of fentanyl, with the advantage of no risks for postoperative respiratory depression.     

Effect of dexmedetomidine on hemodynamic responses to tracheal intubation: A meta-analysis with meta-regression and trial sequential analysis.

Study objectiveAn uncontrolled adrenergic response during tracheal intubation may lead to life-threatening complications. Dexmedetomidine binds to α2-receptors and may attenuate this response. The primary aim of our meta-analysis is to investigate dexmedetomidine efficacy in attenuating sympathetic response to tracheal intubation, compared with placebo or no dexmedetomidine, in terms of heart rate and blood pressure at intubation.DesignMeta-analysis with meta-regression and trial sequential analysis.SettingSystematic search from inception until December 1, 2020 in the following databases: Pubmed, Scopus, the Cochrane Central Register of Controlled Trials, EMBASE and Google Scholar.InterventionsAll randomized controlled trials investigating intravenous dexmedetomidine as premedication in adult patients undergoing tracheal intubation were included in our study. Studies were included without any language or publication date restriction. A trial sequential analysis and a post-hoc meta-regression were performed on the main outcomes.MeasurementsHemodynamic parameters and heart rate at tracheal intubation, dose of anesthetic needed for induction of anesthesia, total anesthetic requirement throughout the operative procedure, postoperative pain and percentage of patients requiring analgesics at 24 postoperative hours, postoperative nausea and vomiting, intraoperative and postoperative bradycardia, hypotension, dizziness, shivering and/or respiratory depression.Main resultsNinety-nine included studies randomized 6833 patients. During laryngoscopy, all hemodynamic parameters were significantly greater in the no dexmedetomidine group. In particular, in the dexmedetomidine group, systolic blood pressure differed by −21.8 mm Hg (95% CI -26.6 to −17.1, p-value < 0.001, I² 97%), mean arterial pressure by −12.8 mm Hg (95% CI -15.6 to −10.0, p-value < 0.001, I² 98%), and heart rate by −16.9 bpm (95% CI −19.8 to −13.9, p-value < 0.001, I² 98%).ConclusionsPatients receiving premedication with dexmedetomidine for tracheal intubation, compared with no dexmedetomidine, have a lower blood pressure and heart rate, however, the risk of bradycardia and hypotension is relevant and its use during daily practice should be cautiously evaluated for each patient.     

DOES ATROPINE PREMEDICATION AFFECT THE CARDIOVASCULAR RESPONSE TO LARYNGOSCOPY AND INTUBATION?

The effect of atropine premedication 1. v and i.m. on the cardiovascularchanges resulting from laryngoscopy and tracheal intubationhas been evaluated in 139 patients undergoing maior surgery.Atropine administered i.v. and i.m. did not affect the hypertensiveresponse to laryngoscopy and tracheal intubation, but did augmentthe tachycardia and increased the frequency of cardiac arrhythmiaobserved during intubation of the trachea.     

EFFECT OF NIFEDIPINE ON CARDIOVASCULAR RESPONSES TO LARYNGOSCOPY AND INTUBATION

The efficacy of sublingual nifedipine in attenuating the pressorresponses to laryngoscopy and intubation was studied in 40 patientsundergoing elective surgery. Anaesthesia was induced with thiopentone5.5 mg kg^–1 i.v. and tracheal intubation was facilitatedwith suxamethonium 1.5 mg kg^–1 i.v. Patients were allocatedrandomly to receive sublingual nifedipine 10 mg or placebo capsules10 min before induction. Patients receiving placebo capsuleshowed significant increases in heart rate and arterial pressureassociated with tracheal intubation (P<0.001). The increasesin arterial pressure and rate-pressure product were reducedin nifedipine treated patients (P<0.001). Heart rate increasedsignificantly in both groups immediately after intubation.     

Gabapentin reduces cardiovascular responses to laryngoscopy and tracheal intubation

BACKGROUND AND OBJECTIVE: We have compared the effects of gabapentin on arterial pressure and heart rate at induction of anaesthesia and tracheal intubation in a randomized double-blind study. METHODS: Ninety normotensive patients (ASA I) undergoing elective surgery were divided into three groups of 30 patients each. Patients received oral placebo (Group I), 400 mg of gabapentin (Group II) or 800 mg of gabapentin (Group III) 1 h prior to surgery in the operating theatre. After induction of anaesthesia heart rate and mean arterial pressure were recorded at baseline 1, 3, 5, 10 and 15 min after intubation. RESULTS: Patients receiving placebo and 400 mg gabapentin showed a significant increase in blood pressure and heart rate associated with tracheal intubation compared to baseline levels and Group III. There was significant decrease in heart rate and arterial pressure in Group III after intubation 1, 3, 5 and 10 min (P < 0.001, P < 0.001, P < 0.05 and P < 0.05, respectively) compared to Groups I and II. CONCLUSION: Given 1 h before operation gabapentin 800 mg blunted the arterial pressure and heart rate increase in first 10 min due to endotracheal intubation. Oral administration of gabapentin 800 mg before induction of anaesthesia is a simple and practical method for attenuating pressor response to laryngoscopy and tracheal intubation after standard elective induction.     

Can esmolol manage surgically-induced tachycardia?

A double-blind, randomised study was conducted to examine the efficacy of a single bolus dose of esmolol in treating surgically-induced tachycardia. Anaesthetic technique was identical in all patients, and consisted of premedication with midazolam and glycopyrronium, induction with thiopentone followed by suxamethonium, tracheal intubation, and maintenance with isoflurane 0.6% (end-tidal) and 60% nitrous oxide in oxygen. Forty-eight patients developed a heart rate of greater than 95 beats/minute or 20% more than pre-induction values at an average time of 34 minutes after tracheal intubation and received placebo (15 patients), esmolol 50 mg (16 patients), or esmolol 100 mg (17 patients). Controlled intervention was instituted if heart rate or blood pressure was not adequate. Both 50 and 100 mg of esmolol resulted in lower heart rates compared to placebo (p less than 0.05), with no difference between the two esmolol groups (p greater than 0.05). Patients who received placebo had more episodes of medical intervention than those given esmolol (p less than 0.05). No adverse effects occurred in any patient.     

Sufentanil or clonidine for blunting the increase in intraocular pressure during rapid-sequence induction

BACKGROUND AND OBJECTIVE: The aim was to determine if the intravenous administration of sufentanil or clonidine before the induction of anaesthesia could obtund the increase of intraocular pressure associated with rapid-sequence induction. METHODS: Thirty-two ASA I-II patients with no history of eye illness scheduled for elective non-ophthalmic surgery were randomly assigned to receive either sufentanil 0.05 microg kg(-1) i.v. (Group A, n = 15) or clonidine 2 microg kg(-1) i.v. (Group B, n = 17) prior to induction. General anaesthesia was induced with thiopental (5 mg kg(-1)) followed by succinylcholine 1 mg kg(-1) to facilitate tracheal intubation. The general anaesthetic technique was standardized in both groups. Intraocular pressure was measured using the Schioetz tonometer just before the succinylcholine administration (t0), just before tracheal intubation (t1) and immediately after intubation (t2). Mean arterial pressure and heart rate were recorded at the same time intervals. RESULTS: Intraocular pressures were similar in both groups at t0, but the sufentanil group had significantly lower values compared with the clonidine group just before (t1) and immediately after tracheal intubation (t2). CONCLUSIONS: Sufentanil is effective in blunting the increase in intraocular pressure caused by rapid-sequence induction with succinylcholine, while clonidine did not seem to have any effect in intraocular pressures just before (t1) and just after (t2) intubation.     

Haemodynamic responses during general anaesthesia for renal transplantation in patients with and without hypertensive disease

Haemodynamic changes in 81 patients undergoing surgery for renal transplantation were studied. They were allocated to three groups depending on whether or not they had chronic hypertension and which drugs were used to control it. The patients in Group I (N = 18, 22%) were normotensive and were not receiving antihypertensive therapy, those in Group II (N = 21, 26%) were taking beta-blockers and those in Group III (N = 42, 52%) both beta-blockers and vasodilating agents. Antihypertensive medication was continued as prescribed until surgery. No anticholinergic premedication was given. All patients received a standardized anaesthesia which included thiopentone, fentanyl, vecuronium and isoflurane. Mean arterial blood pressure and mean heart rate were lowest in Group I compared with the other groups immediately before induction, following vecuronium and thiopentone administration, and after tracheal intubation (P less than 0.05). After the 10-min induction period, blood pressure and heart rate values did not differ between the groups. Although before and during surgery and anaesthesia central venous pressure did not differ between the groups, CVP was higher in Group I postoperatively compared with the other groups (P less than 0.05). No serious anaesthesia-related complications occurred.     

Effects of lidocaine infusion on the sympathetic response to abdominal surgery

Activation of afferent nerves in the area of surgery is a cause for surgical pain and stress. Intravenous (IV) lidocaine has been shown to inhibit postoperative pain. In the present double-blind study, the effects of a continuous IV infusion of lidocaine (2 mg/min) on the sympathoadrenal stress response to surgery were evaluated in 38 patients scheduled for elective cholecystectomy who were randomly assigned to two groups. In one group, lidocaine infusion was started 30 min before the operation and continued for 24 hr after surgery (n = 18). In the second group (n = 20), saline was infused. The increases in heart rate and blood pressure after tracheal intubation were not significantly different between the groups, but tachycardia and hypertension associated with extubation was prevented in patients given lidocaine. Differences in blood pressure and heart rate between the two groups were otherwise not significant intra- or postoperatively, nor were differences in blood glucose or plasma catecholamine concentrations during the first 24 hr after skin incision. Urinary catecholamine concentrations did not differ significantly in the two groups during the first postoperative day, but during the second postoperative day urinary output of epinephrine and norepinephrine were significantly less in the group of patients receiving lidocaine infusion. It was concluded that the IV infusion of lidocaine during and after major abdominal surgery suppresses extubation-induced hypertension and tachycardia but does not inhibit the general sympathetic response during the first postoperative day. However, lidocaine infusion reduces urinary output of catecholamines during the second postoperative day, suggesting a more rapid decline in the sympathoadrenal response postoperatively in the experimental group.     

心脏移植患者术前肺动脉压力与术后并发症的关系及防治

目的分析心脏移植患者术前肺动脉压力和肺血管阻力（PVR）与术后右心功能不全、并发症发生和死亡的关系,总结围术期肺动脉高压的管理经验,以利于心脏移植术后患者早期心功能的恢复。方法125例接受同种原位心脏移植手术的患者,根据术前肺动脉收缩压（PASP）和PVR不同分为两组,肺动脉高压组（n=56）：术前PASP〉50 mm Hg或PVR〉5 Wood.U;对照组（n=69）：术前PASP≤50 mm Hg,PVR≤5 Wood.U。通过Swan-Ganz导管监测两组手术前心脏排血指数（CI）,手术前、后肺动脉     

Effects of beta-adrenoceptor antagonism on the cardiovascular and catecholamine responses to tracheal intubation

The catecholamine and cardiovascular responses to laryngoscopy and tracheal intubation were studied in 20 patients who underwent elective gynaecological surgery and who were allocated randomly to receive either practolol 10 mg or saline intravenously prior to induction of anaesthesia. Anaesthesia was induced with fentanyl and thiopentone; atracurium was administered and the lungs were ventilated artificially with 67% nitrous oxide in oxygen. Tracheal intubation was performed when muscle relaxation was adequate. Arterial pressure, heart rate, plasma noradrenaline and adrenaline concentrations were measured before and after tracheal intubation. A significant increase in catecholamine concentrations occurred in both groups in response to tracheal intubation but the magnitude of the increase in adrenaline was greater in the practolol group. There were no significant differences in arterial pressure or heart rate changes between the groups. We conclude that pretreatment with practolol is of no value in the attenuation of the hypertensive response to direct laryngoscopy and tracheal intubation in previously normotensive patients.     

COMPARISON BETWEEN HIGH-DOSE SUFENTANIL-OXYGEN AND HIGH-DOSE FENTANYL-OXYGEN FOR NEUROANAESTHESIA

The cardiovascular responses to anaesthesia, neurosurgery andthe postoperative administration of naloxone were studied in20 patients. Ten patients were anaesthetized with sufentanil20 µ kg^–1 and 10 with fentanyl 100 µg kg^–1,and oxygen. At 30-min intervals, sufentanil 50 µg or fentanyl250 µg was given to maintain anaesthesia. Mean arterialpressure and heart rate did not increase following intubation,incision of the scalp or infusion of naloxone. Because of inadequateanaesthesia, thiopentone was administered at the end of surgeryto one patient who had received sufentanil and seven patientswho received fentanyl. Apart from one patient in each groupthe tracheal tubes were removed within 1 h of the start of theadministration of naloxone. Recall of tracheal intubation orsurgery was not reported by any patient. High-dose sufentanil-oxygenanaesthesia, like high-dose fentanyl- oxygen anaesthesia, wassatisfactory for use in neurosurgery. However, high-dose narcoticanaesthesia, followed by the postoperative administration ofnaloxone, requires that skilled nursing care be available formany hours after surgery.