Use of nitroglycerin ointment to prevent hypertensive response during electroconvulsive therapy--a study of 50 cases.AL Parab, LS Chaudhari, J Apte
Dept of Anaesthesia, Seth G S Medical College and KEM Hospital, Parel, Bombay.
Fifty patients of either sex, aged between 20 and 60 years undergoing electroconvulsive therapy were included in our study. Each patient was used as his/her own control. We observed the cardiovascular changes without nitroglycerin ointment in the first sitting and in the next sitting with the application of 2 inches of 2% nitroglycerin ointment 45 min before the electroconvulsive therapy. Arterial blood pressure and heart rate increase during electroconvulsive therapy can be effectively attenuated by application of 2 inches of 2% nitroglycerin ointment 45 min before the electroconvulsive therapy (p < 0.001 and p < 0.01 resp.). This may be especially beneficial for patients who are at increased risk of myocardial ischemia and stroke.
Keywords: Adult, Blood Pressure, drug effects,Electroconvulsive Therapy, adverse effects,Female, Heart Rate, drug effects,Human, Hypertension, drug therapy,etiology,physiopathology,Male, Middle Age, Nitroglycerin, administration &dosage,pharmacology,therapeutic use,Ointments,
Electroconvulsive therapy forms an important line of treatment for schizophrenia and depression. The percise mechanism by which the passage of an electric current through the brain should bring about a therapeutic effect in cases of endogenous depression is not yet known. A simple explanation is that it stimulates the mood centre in the hypothalamus. But, in attempting to reach this innermost area of the brain, it may also excite other centres such as the motor cortex.
Electroconvulsive therapy produces maximum strain on the cardiovascular system, leading to transient hypertension and tachycardia. Nitroglycerin ointment with its venodilatory effect may prevent excessive hypertension and increased myocardial oxygen demand. The present study was undertaken to assess the utility of nitroglycerin ointment during electroconvulsive therapy.
Fifty patients (32 males and 18 females) aged between 20 and 60 years undergoing electroconvulsive therapy were included in our study. All patients were of ASA class I and II. Class II patients included hypertensive patients controlled on tablet nifedipine 10mg three times daily and having a normal ECG. There was no evidence of ischemia clinically or on ECG in them before intervention.
All patients were on antipsychotic drugs. The morning dose of drugs was given with sips of water early in the morning.
Inj. atropine 0.01mg/kg body weight was given intramuscularly 30 min before electroconvulsive therapy to all patients. Each patient was used as his/her own control. We observed the cardiovascular changes without nitroglycerin ointment at the first sitting and at the next sitting with the application of 2 inches of 2% nitroglycerin ointment on the chest wall 45 min before electroconvulsive therapy. Continuous ECG monitoring was used.
In the first sitting without nitroglycerin application, heart rate and blood pressure were recorded before induction, after injecting thiopentone sodium (5 mg/kg) and suxamethonium (1 mg/kg) intravenously and after giving electroconvulsive therapy (100 mv, duration 0.8 to 1 sec) at 2, 4, 6, 10, 15, 20, 25, 30, 45, 60, 75, 90, 105 & 120 minutes.
At the next sitting, heart rate and blood pressure were recorded at 5 min intervals after the application of 2 inches of 2% nitroglycerin ointment on the chest wall. After 45 min injection thiopentone sodium (5 mg/kg) and suxamethonium (1 mg/kg) were given followed by electroshock as mentioned earlier. Heart rate and blood pressure were recorded after injecting thiopentone sodium and suxamethonium and after electroshock at 2, 4, 6, 10, 15, 20, 25, 30, 45, 60, 75, 90, 105 and 120 minutes.
After injecting suxamethonium at both sittings, the patient was ventilated with laerdel bag and mask with air and 8 litres/min of oxygen. When the patient was completely relaxed, electroshock of strength 100 MV and duration 0.8 to 1 second was given. Ventilation was continued till spontaneous respiration resumed.
Data were analysed by paired ‘Z’ test. The level of significance used was p < 0.01
In the control (1st sitting) group, 2 min after electroconvulsive therapy, the rise in heart rate was 27.6 beats/min and that in nitroglycerin pre-treatment group was 20.6 beats/min (P < 0.01). At the 1st sitting, heart rate gradually returned to the basal value at the end of 90 min whereas in the nitroglycorin pre-treatment group, the heart rate was higher than the basal value by 6 beats/min at the end of 90 min. [Table - 1]
In, the control (1st sitting) group, 2 min after electroshock, the rise in systolic blood pressure was 34.6 mm Hg. [Table - 2] In nitroglycerin pretreatment group, the rise in systolic blood pressure, 2 min after electroshock was 7.5 mm Hg. (p<0.001)
At the 1st sitting without nitroglycerin pretreatment 2 min after electroconvulsive therapy the rise in rate pressure product was 8355.8 whereas at the 2nd sitting after nitroglycerin pretreatment, it was 5388.4
(p < 0.001).
The cardiovascular effects of electroconvulsive therapy are well known viz tachycardia and hypertension. Hypertension and tachycardia are of rapid onset peaking within 30 seconds, due to direct effect of the sympathetic nervous outflow or in part due to a rise in catecholamine levels, from adrenal meduallary secretion.
The tachycardia and hypertension resulting form electroconvulsive therapy may cause potentially serious adverse reactions such as myocardial infarction or stroke. Cardiac arrest appears to be a leading cause of death associated with the administration of electroconvulsive therapy,. Patients who have coronary artery disease are at great risk. Hypertensive patients are likely to have an exaggerated response and thus, are predlisposed to these complications,.
In an attempt to attenuate the electroconvulsive therapy induced hypotension effectively with a drug that is relatively safe and easy to administer, Lee et al chose nitroglycerin ointment which produces primarily venodilation.
Our results suggest that nitroglycerin ointment as a premedication (2 inches of 2% preparation) 45 minutes before electroconvulsive therapy significantly attenuates electroconvulsive therapy induced hypertension. Nitroglycerin ointment is relatively safe and easy to administer. With topical application, reduction of systolic blood pressure begins within 15 min reaches a maximum in about 60 minutes and the action lasts for 5-6 hours. Two of our patients required intravenous fluid (500 ml 5% Glucose) for treatment of excessive hypotension (systolic B P 80 mmHg). In our follow up visits, no side effects of nitroglycerin ointment e.g. headache, orthostatic hypotension, tachycardia, faintness or flushing were found. Patients recovered from the procedures well, the mean recovery times of the two groups being identical. There was no evidence of ischaemia clinically or on ECG in the control as well as the nitroglycerin group during or after electroconvulsive therapy.
We thank the Dean, Seth GS Medical College and King Edward Memorial Hospital, Mumbai for allowing us to publish this data.
[Table - 1], [Table - 2], [Table - 3]