Glycopyrrolate during ketamine/diazepam anaesthesia A double-blind comparison with atropine

In a double-blind study, the effects of atropine and glycopyrrolate (dosage ratio 2:1) following i.m. and i.v. administration were compared with respect to salivation, heart rate, and blood pressure before, during and after i.v. infusion anaesthesia with ketamine and diazepam for alloplastic hip or knee surgery in 30 patients above the age of 50 years. Given with the premedicant, the two drugs were equally effective in reducing salivation. A slight increase in heart rate was seen after atropine only (P less than 0.005). Increases in heart rate and blood pressure during induction of anaesthesia were similar in the two groups. A second dose of the test drug was given with neostigmine for reversal of neuromuscular blockade. Again, there were no statistically significant differences with respect to salivation, blood pressure, heart rate, nausea and/or vomiting, unpleasant dreams and arousal time.     

The haemodynamic effects of bronchoscopy Comparison of propofol and thiopentone with and without alfentanil pretreatment

The haemodynamic response to bronchoscopy under general anaesthesia was investigated. Forty patients were allocated at random to receive either thiopentone or propofol; half the patients in each group received in addition 18 micrograms/kg of alfentanil one minute before induction of anaesthesia. The heart rate, noninvasive blood pressure and Holter ECG was monitored in all patients. Significant increases in heart rate (p less than 0.05), systolic and diastolic arterial pressures (p less than 0.01) occurred in the thiopentone only group, following bronchoscopy. Systolic and diastolic arterial pressure decreased in patients receiving thiopentone plus alfentanil, following induction of anaesthesia and laryngoscopy (p less than 0.05). No significant haemodynamic changes were seen in either of the groups which received propofol. ST segment changes on subsequent Holter analysis were seen in four patients, but there were no significant differences between the groups. Anaesthesia with propofol alone provides adequate haemodynamic stability for bronchoscopy and the addition is superfluous.     

Atropine before Enflurane Anaesthesia: Effects on Cardiac Rhythm, Pulse Rate, Blood Pressure and Airway Secretion

The occurrence of cardiac arrhythmias and changes in pulse rate and blood pressure during mask anaesthesia with enflurane was investigated in 92 patients with special reference to the influence of atropine (0.01 mg kg-1 5 min before anaesthesia) and thiopental. The average duration of anaesthesia was a little less than 1 h in all four groups. More than five ventricular extrasystoles occurred in one patient (38 min after atropine). Supraventricular (mainly nodal) arrhythmias were significantly (P less than 0.005) more common in the atropine groups (15/45) than in the non-atropine groups (4/47). Following atropine, heart rate increased by about 25 beats min-1, whereas only very slight increases were seen in the non-atropine groups. Blood pressure fell at the induction but was almost back to normal at the end of anaesthesia. Blood pressure was unaffected by atropine. Slightly lower values of blood pressure were suggested in the thiopental groups, whereas thiopental did not modify cardiac rhythm or pulse rate. Suction of the pharynx was necessary in only one patient. In conclusion, the present study does not support the routine administration of atropine before enflurane anaesthesia with or without thiopental induction.     

Isosorbide dinitrate spray. Attenuation of cardiovascular responses to laryngoscopy and intubation.

We evaluated the efficacy of isosorbide dinitrate buccal spray (Isomack) in attenuating the cardiovascular response to laryngoscopy and tracheal intubation in 60 patients undergoing elective surgery under general anaesthesia. Patients were allocated to one of three groups of 20 patients each. Group 1 patients were administered placebo buccal spray 90 s before induction of anaesthesia. Groups 2 and 3 had isosorbide dinitrate spray 30 and 90 s before induction of anaesthesia. Systolic, diastolic and mean arterial pressures and heart rate were monitored. After the spray, group 3 patients had a significant decrease in systolic arterial pressure (p less than 0.01). At 1 min after intubation, systolic, diastolic and mean arterial pressures showed a significant increase in group 1 patients (24.9 mmHg, 14.2 mmHg and 18.7 mmHg respectively). In contrast, groups 2 and 3 showed a significant decrease in these parameters (p less than 0.01). Although significant tachycardia was present following intubation in all the three groups, the degree of tachycardia was greater in groups 2 and 3 (p less than 0.01).     

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.     

Haemodynamic effects of rapacuronium in adults with coronary artery or valvular disease

We have assessed the haemodynamic effects of rapacuronium (Org 9487) in adults undergoing cardiac surgery and compared these with vecuronium and placebo. We studied 56 adult patients undergoing coronary artery bypass grafting or valve replacement surgery using a fentanyl-based anaesthetic technique. A pulmonary artery flotation catheter was inserted before induction of anaesthesia. After induction, tracheal intubation and stabilization of haemodynamic measurements, subjects were allocated randomly to receive rapacuronium 1.5 mg kg-1 vecuronium 0.1 mg kg-1 or saline placebo. Haemodynamic measurements were made before drug administration and 1, 3, 5 and 10, and if possible, 15 min after administration. Rapacuronium was associated with statistically significant increases in heart rate (17%) and cardiac index (15%) and decreases in mean arterial pressure (11%) and systemic vascular resistance (18%), whereas vecuronium and placebo were associated with significant decreases in heart rate only (14-15%) (P < 0.05). No cutaneous signs of histamine release were observed. Clinically, the results were within acceptable limits. Our results suggest that administration of rapacuronium may be associated with significant changes in heart rate and arterial pressure in patients undergoing coronary artery bypass grafting.      

Comparison of midazolam and diazepam to supplement total intravenous anaesthesia with ketamine for endoscopy

Fifty patients undergoing endoscopy (laryngoscopy, bronchoscopy, mediastinoscopy) were anaesthetised in a double-blind prospective trial using total intravenous anaesthesia. Half of the patients were anaesthetised with an infusion of a solution of 250 mg ketamine and 12.5 mg midazolam. The other patients received an infusion of a solution of 250 mg ketamine and 20 mg diazepam. In addition, both groups were given increments of 50-100 micrograms of fentanyl. The immediate awakening time (t1) was not significantly different between groups, but the patients who had received midazolam-ketamine, had a significantly shorter time to more complete recovery (t2), a significantly lower frequency of emergence reactions and were more satisfied with the anaesthetic than the patients who had received diazepam-ketamine. There was no difference between groups with respect to intraoperative heart rate and blood pressure. No awareness during anaesthesia was reported.     

Nifedipine attenuates the intraocular pressure response to intubation following succinylcholine

Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied to evaluate the efficacy of sublingual nifedipine in attenuating the intraocular pressure response to succinylcholine administration, laryngoscopy and intubation. The patients were randomly given either nifedipine 10 mg or placebo sublingually 20 minutes before induction of anaesthesia. Intraocular pressure (IOP) and systolic blood pressure (SBP) were recorded before and after induction of anaesthesia. The IOP response to succinylcholine administration, laryngoscopy and intubation was significantly less in patients receiving nifedipine (P > 0.01). The mean maximum rise in IOP above basal level at one minute postintubation was 7.82 mmHg in the control group compared with 0.15 mmHg in the nifedipine pretreated group. These results suggest that sublingual nifedipine is effective in attenuating the IOP response after succinylcholine administration, laryngoscopy and 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.     

Haemodynamic changes during induction of anaesthesia with midazolam and diazepam (Valium) in patients undergoing coronary artery bypass surgery

Midazolam 0.3 mg/kg and diazepam 0.5 mg/kg were used for induction of anaesthesia in two groups of 10 patients each undergoing coronary artery bypass surgery. Haemodynamic variables were measured during induction of anaesthesia, after pancuronium and following tracheal intubation. Haemodynamic indices were derived from these measurements using standard formulae. The induction of anaesthesia with midazolam produced a slight but significant increase in heart rate. There was a significant fall in systemic arterial pressure and pulmonary artery pressure following both drugs. Despite the fall in systemic arterial pressure, the cardiac index was maintained in patients who received midazolam. The cardio-stimulatory effect of laryngoscopy and tracheal intubation was not prevented by either of the benzodiazepines and morphine in the dosage used. Midazolam is a suitable alternative to diazepam as part of an intravenous induction regimen in patients with ischaemic heart disease.     

Effect of i.v. Atropine on Cardiac Rhythm, Heart Rate, Blood Pressure and Airway Secretion during Isoflurane Anaesthesia

Atropine, 0.01 mg kg-^-1, was given i.v. to 30 patients before mask anaesthesia with isoflurane. Controls (n = 28) received a placebo. ECG was recorded on tape throughout anaesthesia and analysed later. There were no ventricular arrhythmias, but six patients in the atropine group and two patients in the placebo group had supraventricular arrhythmias of very short duration. Most cases occurred shortly after atropine, i.e. before anaesthesia. Heart rate increased significantly in both groups, more so after atropine (up to 60%), and remained elevated. In both groups blood pressure fell after the induction of anaesthesia but was close to control during surgery. Suction of airway secretions was necessary in three placebo patients, but excessive secretions were not met. The frequency of airway reflexes was similar in the two groups. It is concluded that due to the pronounced tachycardia the routine use of i.v. atropine can hardly be recommended before mask anaesthesia with isoflurane.     

Intranasal nitroglycerine attenuates pressor response to tracheal intubation in beta-blocker treated hypertensive patients

The effect of intranasal nitroglycerine on the pressor response to laryngoscopy and tracheal intubation was studied in 40 adult hypertensive patients treated with beta-blocking drugs. Nitroglycerine 0.75 mg, administered intranasally 30 seconds before induction of anaesthesia, was compared with a placebo solution of saline. Haemodynamic variables were measured for 10 minutes after laryngoscopy and tracheal intubation. Heart rate did not change significantly in either group. Systolic as well as mean arterial blood pressure increased significantly for the first 5 minutes in the control group, whereas patients in the nitroglycerine group showed a decrease in systolic as well as in mean arterial pressure. No patient in the nitroglycerine group showed a decrease in systolic arterial pressure greater than 20 mmHg. In conclusion, intranasal nitroglycerine ameliorates the pressor response to laryngoscopy and tracheal intubation in beta-blocked patients.     

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.     

Beta-adrenoceptor blockade and anaesthesia

Twenty-six patients with severe coronary artery disease, receiving long term beta-adrenoceptor blocking drugs were anaesthetised for aorto-coronary bypass operations. Beta-adrenoceptor blocking drugs were withdrawn 2 to 8 days before surgery in ten patients only. In the remaining sixteen patients there were no serious complications due to the presence of a degree of beta-blockade during anaesthesia and surgery. The undesirable cardiovascular responses to laryngoscopy and tracheal intubation were diminished in these patients, and the rise in heart rate/systolic pressure product, and indicator of myocardial oxygen consumption, was less in this group. The need for peripheral vasodilators to treat systemic arterial pressure rises in response to surgery was also reduced. There appeared to be no contraindication to the continuation of beta-adrenoceptor blockade before operation in patients undergoing aorto-coronary bypass procedures when suitable anaesthetic agents were selected and when an appropriate blood volume was maintained.     

Comparison of Some Postanaesthetic Effects of Atropine and Glycopyrrolate with Particular Emphasis on Urinary Problems

Two hundred and two patients undergoing elective surgery were given either atropine (98 patients) or glycopyrrolate (104 patients) for intravenous premedication and as an adjunct to reversal of neuromuscular block by neostigmine in a double-blind study. The dose ratio of atropine and glycopyrrolate was 2.5:1. After reversal, both drugs induced an initial increase and a subsequent decrease in heart rate. The mean values in % heart rate were statistically significantly higher in the glycopyrrolate group than in the atropine group. Semiquantitative measurement of salivation showed glycopyrrolate to be more potent as an antisialogogue drug. Nausea and vomiting were equally common after both drugs. There were no differences between the drugs in the occurrence of postoperative micturition difficulties, the total rate of this complication being 18%. It is concluded that factors other than the choice of anticholinergic drug may be blamed for postoperative micturition difficulties.     

Preoperative oral dextromethorphan vs. clonidine to prevent tourniquet-induced cardiovascular responses in orthopaedic patients under general anaesthesia

BACKGROUND AND OBJECTIVE: Preoperative oral dextromethorphan and intravenous clonidine attenuate arterial pressure and heart rate increases during tourniquet inflation under general anaesthesia. The effect of preoperative oral clonidine on these variables has not been investigated. METHODS: We designed this study to compare the effect of preoperative oral dextromethorphan or clonidine on haemodynamic changes during tourniquet inflation in 75 patients undergoing lower limb surgery under general anaesthesia. Patients were randomly assigned into three groups: dextromethorphan 30 mg (n = 25), clonidine 3 microg kg(-1) (n = 25) and placebo (n = 25). Anaesthesia was maintained with isoflurane 1.2% and N2O 50% in oxygen with endotracheal intubation. Dextromethorphan, clonidine or placebo was given orally in a double-blinded fashion 90 min before induction of anaesthesia. Systolic, diastolic and mean arterial pressure and heart rate were measured at 0, 30, 45, 60 min after the start of tourniquet inflation, before tourniquet release and 20 min after tourniquet deflation. RESULTS: Systolic, diastolic and mean arterial pressure were significantly lower in the clonidine group compared with control after 45, 60 min tourniquet inflation and before tourniquet release (P < 0.05). Twenty minutes after deflation, diastolic and mean arterial pressure in the control group were still increased and significantly higher compared with the clonidine group (P < 0.05). Development of more than a 30% increase in systolic arterial pressure during tourniquet inflation was more frequent in the control group than in the other groups. CONCLUSIONS: Preoperative oral clonidine 3 microg kg(-1) significantly prevented tourniquet-induced systemic arterial pressure increase in patients under general anaesthesia better than oral dextromethorphan.     

Haemodynamic effects of ketamine and thiopentone during anaesthetic induction for caesarean section

Ketamine (1 mg . kg-1) or thiopentone (4 mg . kg-1) was used to induce anaesthesia for Caesarean section in 62 normotensive patients. During induction of anaesthesia and before laryngoscopy, blood pressure did not change in either group (preinduction systolic blood pressure, 131 mmHg, and diastolic blood pressure, 75 mmHg). When laryngoscopy and intubation were performed, mean blood pressures of both patient groups increased 20-30 per cent. With ketamine (n = 30) heart rate was unchanged from the preinduction rate of 85 beats/min before laryngoscopy and increased significantly by 15 per cent during laryngoscopy and intubation. With thiopentone (n = 32), heart rate increased significantly to 20 per cent above the preinduction rate of 87 beats/min during induction and increased further (to 35 per cent above the preinduction rate) during laryngoscopy and intubation. The average maximal rate-pressure product calculated for the thiopentone group was over 18,000, which was significantly higher than the 15,000 calculated for the ketamine group. Neonatal outcome as assessed by Apgar score and umbilical blood gas analysis was good and did not differ significantly between groups.     

The use of intravenous atropine after a saline infusion in the prevention of spinal anesthesia-induced hypotension in elderly patients

We investigated the efficacy of IV atropine for preventing spinal anesthesia-induced hypotension in elderly patients. Seventy-five patients undergoing transurethral prostate or bladder surgery were randomized to receive either placebo (n = 25), atropine 5 microg/kg (small-dose atropine, n = 25) or atropine 10 microg/kg (large-dose atropine, n = 25) after the induction of spinal anesthesia. All the patients received an IV infusion of 10 mL/kg 0.9% normal saline over 10 min before the induction of anesthesia. The systolic blood pressure decreased in all three groups after spinal anesthesia. There was a significant increase in the mean heart rate in both atropine groups as compared to the placebo group (placebo group: 78 bpm, 95% confidence interval [CI]: 76.6-78.5; small-dose atropine group: 86 bpm, 95% CI 83.9-88.8; large-dose atropine group: 97 bpm, 95% CI 94.5-100.3; P: = 0.001). There was a significant decrease in the incidence of hypotension in patients who received atropine (placebo group: 76%, small-dose atropine group: 52%, large-dose atropine group: 40%, P: = 0.03). The mean dose of ephedrine required was significantly decreased in the atropine groups (placebo group: 12.2 mg [SD= 10.5], small-dose atropine group: 7.4 mg [SD= 10.0], large-dose atropine group: 5.4 mg [SD= 8.7 mg], P: = 0.048). The total amount of IV fluid and number of patients requiring metaraminol in addition to 30 mg of ephedrine were not significantly different among the three groups. Significant side effects, such as confusion, ST segment changes or angina were not detected in any of the patients. We conclude that IV atropine may be a useful supplement to the existing methods in preventing hypotension induced by spinal anesthesia. Implications: IV atropine increases heart rate in a dose-dependent manner in elderly patients undergoing spinal anesthesia. It reduces the incidence of hypotension and the dose of ephedrine required. Small-dose atropine may be a useful supplement in preventing spinal anesthesia-induced hypotension in elderly patients.     

Anticholinergic pre-treatment in rigid bronchoscopy. Effect on heart rate, arterial blood pressure and cardiac arrhythmias

The effect of anticholinergic pre-treatment on the hemodynamic changes during rigid bronchoscopy was studied. Eighty four adult patients in three groups received intravenous saline (control), atropine or glycopyrrolate several minutes before anesthesia and venturi ventilation with intermittent thiopentone and suxamethonium. The rises in heart rate and blood pressure and the incidence of cardiac dysrhythmias were least in the control group. Transient bradycardia rarely occurred, even in the control group, despite repeat doses of suxamethonium. Although most of the results were not statistically significant, they suggest that preoperative anticholinergic administration may aggravate some of the cardiovascular effects of bronchoscopy resulting from sympathoadrenal stimulation.     

Cardiovascular effects of a combination of vecuronium and low-dose fentanyl in atropinized and non-atropinized subjects]

The cardiovascular effects of the pharmacologic association of low-dose fentanyl (2 micrograms/kg) and vecuronium (120 micrograms/kg) have been studied in 38 ASA I and II atropinized and non-atropinized patients scheduled for abdominal surgery during induction of anaesthesia with thiopentone or propofol. Whatever the induction agent used, heart rate was consistently reduced in patients not receiving an anticholinergic drug, while it was unchanged in patients treated with atropine intravenously. In non-atropinized patients impressively lower minimum heart rates were observed during induction of anaesthesia with thiopentone. In this last group one patient suffered from a cardiac arrest resolved without sequelae. In patients treated with the association between vecuronium and low doses of fentanyl a pretreatment with atropine is always indicated. Propofol seems to be a better induction agent than thiopentone.