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Pressor responses after tracheal extubation or LMA removal in controlled hypertensive patients
Abstract
The present study was undertaken in controlled hypertensive patients to determine haemodynamic responses after tracheal extubation or removal of LMA. Forty patients of either sex, belonging to ASA status II, undergoing elective surgical procedures were studied in a randomised manner. They were divided into two groups of twenty patients each, depending on whether endotracheal tube (ETT group) or LMA (LMA group) was used. Heart rate, blood pressure (systolic & diastolic) and rate pressure product were measured at 1, 2, 3, 5 and 10 minutes after endotracheal tube extubation or removal of LMA. Heart rate, blood pressure (SAP and DAP) and rate pressure product increased significantly in both the groups, but the increase in these variables was highly significant and prolonged in ETT group after extubation as compared to LMA group. In conclusion, LMA removal was found to be accompanied with lesser pressor response as compared to endotracheal tube extubation in hypertensive patients.
Opthalmic Surgery has optimal results if the intraocular pressure is well controlled during the perioperative period. Increasingly patients with coronary and hypertensive heart disease are posted for elective procedures under general anaesthesia. Keeping both these subpopulations in mind intraocular pressure (IOP), Heart Rate (HR), Systolic (SP) and Diastolic Pressure (DP) were measured in 100 patients at the time of intubation/laryngeal mask airway insertion and extubation/LMA removal. There was a significant rise in IOP, HR, SP and DP in the group that was intubated as compared to the group in whom the LMA was used at both events. Statistical tests of significance used were paired and unpaired 't' test. Laryngeal mask.
Tracheal extubation in the post coronary artery bypass graft patient is followed by intense cardiovascular stimulation persisting for at least ten minutes, and intravenous lidocaine (1.5 mg/kg) does not alter these changes. It is concluded that even though no patient in this study developed arrhythmia, angina, or infarction during or following extubation, their potential would seem apparent from the results. Thus, cardiovascular monitoring would be appropriate following extubation in these patients.
Purpose
Tracheal extubation produces haemodynamic changes that may cause myocardial ischaemia in patients with coronary arterial disease. Intravenous infusion of prostaglandin El (PGE1) attenuated the hypertensive response to tracheal extubation but failed to blunt the tachycardia, which was attenuated by intravenous lidocaine. Thus, we investigated whether a combination of PGE, and lidocaine can overcome the drawbacks of treatment with PGE1, alone.
Methods
One hundred adult patients (ASA 1) undergoing elective minor surgery were randomly assigned to receive one of four treatments: saline (as a control), I mg·kg−1 lidocaine, infusion of 0.1 μg−1·kg−1·min−1 PGE1, or infusion of 0.1 μg−1·kg−1 min−1 PGE1 plus injection of I mg−1·kg/−1 lidocaine. Lidocaine was injected two minutes before tracheal extubation. The PGE, was infused from completion of surgery until five minutes after tracheal extubation. Anaesthesia was maintained with sevoflurane 1.0%–2.5% and nitrous oxide 60%. Heart rate (HR) and blood pressure (BP) were measured before and after tracheal extubation.
Results
Lidocaine alone and PGE1-lidocaine combination attenuated the increases in BP and HR observed in the control group: PGE1 alone was effective in attenuating hypertensive response but ineffective for tachycardia. The suppressive effect of the PGE1 -lidocaine combination on BP increase was superior to that of each drug alone, and the combined effect on HR increase was similar to that of lidocaine alone.
Conclusion
The combination of PGE1 infusion and lidocaine is a more effective method of attenuating hypertension and tachycardia associated with tracheal extubation than either drug alone.
The results of this study demonstrate that 60 mg of lidocaine sprayed down the tracheal tube before extubation and 40 mg sprayed down the tracheal tube before extubation and 40 mg sprayed down during tracheal tube removal prevents increases in blood pressure and pulse rate during and after extubation. The data suggest that this manoeuvre should be of advantage to patients with coronary artery disease who may not be able to tolerate the increased cardiac dynamics which usually accompany extubation.
This study was undertaken to evaluate the haemodynamic changes of tracheal extubation or removal of a laryngeal mask airway (LMA) in normotensive and hypertensive patients.
In a randomized trial of normotensive and hypertensive patients (n = 40 of each), tracheal extubation or LMA removal was performed. Changes in heart rate (HR), mean arterial pressure (MAP) and rate-pressure product (RPP) were measured before and 1, 2, 3, 5, and 10 min after tracheal extubation or LMA removal.
In normotensive patients, HR, MAP and RPP increased following tracheal extubation or LMA removal, and remained elevated for a maximum three minutes (P < 0.05). In hypertensive patients, the haemodynamic increases in response to extubation or LMA removal were observed for up to five minutes (P < 0.05). The immediate cardiovascular responses to extubation were greater than those related to LMA removal in both normotensive and hypertensive patients (normotensive: HR; 95 +/- 14 vs 81 +/- 11, MAP; 124 +/- 18 vs 106 +/- 10, RPP; 14,951 +/- 2720 vs 10,654 +/- 1898, hypertensive: HR 105 +/- 10 vs 87 +/- 13, MAP; 146 +/- 17 vs 119 +/- 12, RPP; 20,492 +/- 1674 vs 12,862 +/- 2115, mean +/- SD, P < 0.05). Following extubation or LMA removal, these haemodynamic variables increased more markedly in hypertensive patients than in normotensive patients (P < 0.05).
Removal of LMA is associated with less cardiovascular change than tracheal extubation in both normotensive and hypertensive patients.