Attenuation of haemodynamic responses to tracheal intubation by the styletscope

Tracheal intubation often causes a haemodynamic response probablygenerated by direct laryngoscopy. The StyletScope is a new intubationdevice that does not require direct laryngoscopy. We prospectivelymeasured haemodynamic changes after tracheal intubation usingthe StyletScope. The increase of heart rate was less duringtracheal intubation with the StyletScope when compared withthe Macintosh laryngoscope. Br J Anaesth 2001; 86: 275–7     

Comparison of haemodynamic responses to tracheal intubation using the Airway Scope® and Macintosh laryngoscope in normotensive and hypertensive patients

We compared the effects of the Airway Scope^® on haemodynamic responses during tracheal intubation with those of direct laryngoscopy in normotensive and hypertensive patients. The systolic blood pressure, diastolic blood pressures and heart rate were recorded: (a) before anaesthesia; (b) immediately before intubation; (c) at intubation; and (d) 1, 2, 3, 4 and 5 min after intubation. In normotensive patients, the increase in blood pressure and heart rate over time were significantly lower with the Airway Scope than with the Macintosh laryngoscope (p < 0.003). In hypertensive patients, however, there was no difference in the changes over time in any of these haemodynamic measures between the two devices (p > 0.05). We conclude that the Airway Scope attenuates haemodynamic responses to tracheal intubation in comparison with the laryngoscope in normotensive but not in hypertensive patients. You can respond to this article at http://www.anaesthesiacorrespondence.com     

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.     

Effects of nicardipine on the circulatory responses to tracheal intubation in normotensive and hypertensive patients

This study was undertaken to examine the effects of nicardipine on circulatory responses to laryngoscopy and tracheal intubation in normotensive (n = 39) and hypertensive (n = 36) patients. Laryngoscopy and tracheal intubation were performed after induction of anaesthesia with thiamylal, followed by administration of intravenous saline or nicardipine 20 or 30 micrograms.kg-1 and suxamethonium. Blood pressure and heart rate were recorded, and rate-pressure product was calculated. Nicardipine 20 and 30 micrograms.kg-1 prevented the increase in mean arterial pressure after intubation in normotensive and hypertensive patients (p less than 0.01 compared with saline). The changes in heart rate after intubation were significantly greater in normotensive patients than in hypertensive patients when 20 or 30 micrograms.kg-1 of nicardipine was given (p less than 0.05 and p less than 0.01 respectively). Rate-pressure product increased significantly (p less than 0.01) after intubation in normotensive patients whether nicardipine was administered or not, but the increase was suppressed completely by nicardipine 20 or 30 micrograms.kg-1 in hypertensive patients. We conclude that nicardipine is effective in preventing the circulatory responses to laryngoscopy and tracheal intubation in hypertensive patients.     

Hemodynamic responses among three tracheal intubation devices in normotensive and hypertensive patients

We compare hemodynamic responses in normotensive and hypertensive anesthetized paralyzed patients among three intubation devices: the Macintosh laryngoscope (LS), the Trachlight lightwand (LW), and the intubating laryngeal mask airway Fastrach (ILM). Seventy-five normotensive and 75 hypertensive patients were randomly assigned to each intubation device (n = 25). Noninvasive systolic blood pressure (SBP) and diastolic blood pressure (DBP) and heart rate (HR) were recorded immediately preinduction, immediately preintubation, and every minute for the first 5 min after the successful intubation. The number of intubation attempts, the time to successful intubation, and any airway injuries were recorded. Pharyngolaryngeal morbidity was assessed 18-24 h after surgery by a blinded investigator. In all groups, there was a reduction in SBP and DBP but no change in HR immediately preintubation compared with baseline values. In all groups, HR increased, but there were no increases in SBP and DBP other than in DBP in the LS/hypertensive group after intubation compared with baseline values. In normotensive patients, there were no differences in any hemodynamic variables among the three devices. In hypertensive patients, SBP and DBP in the LS group were significantly higher than the ILM and LW groups for 2 min after intubation, but there were no differences in HR among the devices. The number of intubation attempts was similar among groups, but intubation time was longer for the ILM group. The incidence of airway injury was more frequent for the ILM than the LS and LW groups (16% versus 0% versus 0%). There were no differences in pharyngolaryngeal morbidity among groups. We conclude that both the ILM and the LW attenuated the hemodynamic stress response to tracheal intubation compared with the LS in hypertensive, but not in normotensive, anesthetized paralyzed patients. IMPLICATIONS: Both the intubating laryngeal mask airway Fastrach and the Trachlight lightwand attenuate the hemodynamic stress response to tracheal intubation compared with the Macintosh laryngoscope in hypertensive, but not in normotensive, anesthetized paralyzed patients.     

Cigarette smoking and the haemodynamic response to tracheal intubation

This study investigated the effects of smoking and gender on the haemodynamic response after tracheal intubation. Patients were assigned to one of four groups: female non-smokers, female smokers, male non-smokers and male smokers. After tracheal intubation, the highest mean (SD) increase in heart rate (30 (18) %) and rate–pressure product (40 (29) %) was seen in male smokers. The increases in heart rate and rate–pressure product in male smokers were significantly greater than those in female non-smokers, p < 0.05. The increase in rate–pressure product was significantly greater in male smokers than in male non-smokers, p = 0.022.     

RETRACTED ARTICLE: Diltiazem-lidocaine combination for the attenuation of cardiovascular responses to tracheal intubation in hypertensive patients

Purpose

Hypertensive patients are prone to haemodynamic changes after laryngoscopy and tracheal intubation. This study was undertaken to compare the efficacy of a combination of diltiazem and lidocaine with that of each drug alone for suppressing the cardiovascular responses to trachéal intubation.

Methods

Sixty hypertensive patients (ASA II), defined as systolic blood pressure > 160 mmHg and/or diastolic blood pressure > 95 mmHg (World Health Organization), undergoing elective surgery received, in a randomized, double-blind manner, 0.3 mg·kg^?1 diltiazem, 1.5 mg·kg^?1 lidocaine, or 0.3 mg·kg^?1 diltiazem plus 1.5 mg·kg^?1 lidocaineiv (n = 20 of each) before the initiation of laryngoscopy. Anaesthesia was induced with 5 mg·kg^?1 thiopentoneiv, and tracheal intubation was facilitated with 2 mg·kg^?1 succinylcholineiv after precurarization with 0.02 mg·kg^?1 vecuroniumiv. Changes in heart rate (HR), mean arterial pressure (MAP) and rate-pressure product (RPP) were measured before and at immediate, 1, 2, 3, 5 and 10 min after tracheal intubation.

Results

The inhibitory effects of diltiazem-lidocaine combination on cardiovascular responses to tracheal intubation was greater than those of diltiazem or lidocaine as a sole medicine (RPP; 10602 ± 1448 (combination)vs 11787 ± 1345 (diltiazem), 15428 ± 1756 (lidocaine), mean ± SD,P < 0.05).

Conclusion

Prophylactic therapy with diltiazem-lidocaine combination is more effective than diltiazem or lidocaine alone for attenuating the cardiovascular changes associated with tracheal intubation in hypertensive patients.     

Reducing the haemodynamic responses to laryngoscopy and intubation

The effects of alfentanil and fentanyl on controlling the haemodynamic responses to laryngoscopy and intubation have been compared. Five groups of ten patients were studied. Induction was with thiopentone 4 mg/kg. Thirty seconds later group 1 received 1 ml/20 kg saline, group 2 received 15 micrograms/kg alfentanil, group 3 received 30 micrograms/kg alfentanil and group 4 received 5 micrograms/kg fentanyl one minute before induction. Suxamethonium was given 60 seconds after induction and intubation of the trachea was performed 150 seconds after the start of induction. Heart rate and mean arterial pressure were recorded every minute throughout and compared with pre-induction control values. Control patients (group 1) showed significant increases associated with tracheal intubation in all haemodynamic variables. No increases were noted in groups receiving 30 micrograms/kg alfentanil or 5 micrograms/kg fentanyl. The heart rate, but not blood pressure, increased with intubation after 15 micrograms/kg alfentanil. The mean time to movement in 50% of the control patients was 7 minutes. In those given 15 and 30 micrograms/kg alfentanil it was 11 and 12 minutes respectively. In those given 5 micrograms/kg fentanyl it was greater than 15 minutes. Alfentanil is shown to reduce the cardiovascular responses to laryngoscopy and intubation and the effect appears to have a shorter duration than that of fentanyl.     

Prostaglandin E1 (PGE1) prevents the pressure responses to tracheal intubation in hypertensive patients]

Forty-five hypertensive patients for elective abdominal surgery were investigated regarding the effects of PGE1 on the cardiovascular responses to tracheal intubation. Administration of PGE1 at the dose of 0.10 or 0.20 micrograms.kg-1.min-1 for 10 minutes before tracheal intubation significantly reduced the blood pressure responses immediately after the intubation and 2 minutes later. The increases in heart rate were not altered with and without the administration of PGE1. So the increases in rate pressure products were markedly reduced with PGE1 compared with the control values. Plasma concentration of catecholamines was measured before and after tracheal intubation. Norepinephrine was elevated markedly immediately after the intubation and this change was not affected by the infusion of PGE1. These results demonstrate that PGE1 ameliorates the pressure responses by the release of norepinephrine and thus reduces the increases in rate pressure products immediately after tracheal intubation.     

RETRACTED ARTICLE: Circulatory responses to laryngeal mask airway insertion or tracheal intubation in normotensive and hypertensive patients

The effects of laryngeal mask airway (LMA) insertion and tracheal intubation on circulatory responses were studied in normotensive (n = 24) and hypertensive (n = 22) patients. In a randomized, double-blind manner, LMA insertion or tracheal intubation was performed after induction of anaesthesia with thiopentone and muscle relaxation with succinylcholine. In both normotensive and hypertensive patients, heart rate (HR), mean arterial pressure (MAP) and rate-pressure product increased after tracheal intubation or LMA insertion compared with base-line (P < 0.05). The haemodynamic changes were greater after intubation than after LMA insertion (P < 0.05). Following intubation of the trachea or insertion of the LMA, HR increased more markedly in hypertensive patients than in normotensive patients (P < 0.05). Plasma adrenaline and noradrenaline concentrations after tracheal intubation or LMA insertion increased compared with baseline values (P < 0.05) in normotensive and hypertensive patients. The increase in noradrenaline concentration after tracheal intubation was greater than that after LMA insertion (P < 0.05). No patient revealed ECG evidence of myocardial ischaemia. We conclude that insertion of LMA is associated with less circulatory responses than tracheal intubation in both normotensive and hypertensive patients.     

Effect of oral gabapentin on the intraocular pressure and haemodynamic responses induced by tracheal intubation

Background: Laryngoscopy and tracheal intubation may cause undesirable increases in blood pressure, heart rate (HR) and intraocular pressure (IOP). Gabapentin has been used effectively to attenuate the pressor response to laryngoscopy and tracheal intubation. We investigated whether the pre-treatment with gabapentin attenuates the IOP in addition to a haemodynamic response to tracheal intubation.
Methods: Sixty ASA I–II patients were randomly allocated into two groups who received either gabapentin (800 mg) or placebo 2 h before surgery. IOP, mean arterial pressure (MAP) and HR were measured before and after the induction of anaesthesia as well as at 0, 1, 3, 5, 10 and 15 min following intubation.
Results: IOP and MAP increased from baseline immediately after intubation in the placebo group ( P =0.001 and 0.002, respectively). When compared with the placebo group, IOP values of the gabapentin group were significantly lower for the first 15 min after tracheal intubation ( P =0.002 at 0 min, P =0.006 at 1 min, P <0.001 at 3 min, P <0.001 at 5 min, P <0.001 at 10 min and P =0.003 at 15 min) while MAP was lower in the first 10 min ( P =0.001 at 0 min, P =0.002 at 1 min, P <0.001 at 3 min, P <0.001 at 5 min and P =0.028 at 10 min). These results showed that gabapentin effectively suppresses the increase in IOP secondary to endotracheal intubation and attenuates the increases in MAP.
Conclusion: It is suggested that gabapentin is a useful adjuvant in order to prevent an increase in the IOP in response to laryngoscopy and tracheal intubation.     

Evaluation of remifentanil for control of haemodynamic response to tracheal intubation

We have studied the effect of three bolus doses of remifentanil on the haemodynamic response to laryngoscopy and tracheal intubation. Using a double-blind design, 80 ASA 1 or 2 patients presenting for elective surgery received saline placebo or remifentanil 0.25, 0.5 or 1.0 microgram.kg-1 by random allocation. Anaesthesia was induced with thiopentone 5-7 mg.kg-1 and followed immediately by the study medication given as a bolus over 30s. Muscle relaxation was provided with rocuronium 0.75 mg.kg-1. The patients' tracheas were intubated under direct laryngoscopy 1 min later. Noninvasive arterial blood pressure and heart rate were recorded immediately before induction of anaesthesia and then at intervals until 5 min after tracheal intubation. There was a significant increase in heart rate (p < 0.01) and systolic arterial pressure (p < 0.01) in all groups after tracheal intubation. However, this was short-lived and of a smaller magnitude in the remifentanil 1 microgram.kg-1 group in which the increase was significantly lower than in the control group (p < 0.01).     

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.     

Modification of the haemodynamic responses to induction of anaesthesia and tracheal intubation with alfentanil,esmolol and their combination

The purpose of this double-blind randomized work was to study the effect of alfentanil and esmolol and their half-dose combination on the increases of heart rate and arterial pressure and on the prolongation of the QTc interval of the ECG occurring during anaesthetic induction. Sixty ASA class I– II patients with mean age ranging from 26 to 32 yr among the groups. Patients were allocated to one of four equal groups to receive saline, esmolol 2 mg · kg^{? 1}, alfentanil 0.03 mg · kg^{? 1} and alfentanil 0.015 mg · kg^{? 1} + esmolol 1 mg · kg^{? 1}. Anaesthesia was induced with thiopentone. Succinylcholine was used to facilitate tracheal intubation. Haemodynamic variables were measured non-invasively and the QTc interval with the aid of a microcomputer. Comparisons between the groups were performed using two-way analysis of variance with repeated measures. Both alfentanil and alfentanil-esmolol prevented the increase of heart rate and arterial pressure caused by intubation whereas esmolol prevented only the increase of the heart rate. None of the treatments prevented prolongation of the QTc interval after intubation and only alfentanil prevented that after succinylcholine. The present results suggest that in the prevention of the haemodynamic responses to tracheal intubation, the half-dose combination of alfentanil and esmolol is as effective as alfentanil and superior to esmolol. The combination is preferable to relatively large doses of either drug in circumstances where side effects, such as respiratory depression due to alfentanil or bradycardia due to both drugs should be minimized.