 |
|
||||
|
|||||
| About | Latest Articles | Back-Issues | Articles
|
Search | Instructions | Online Submission | Subscribe | Etcetera | Contact |
| |||||||||||||||||||||
|
Comparative evaluation of propanidid with thiopentone as an anaesthetic agent for electro-convulsive therapy.
Electro-convulsive treatment has a prominent place in modern psychiatry. Most psychiatrists agree that electro convulsive treatment (ECT) needs some form of anaesthesia. In its absence mentally ill patients may refuse to co-operate and develop a certain amount of fear and aversion for this often repeated treatment. Anaesthesia also alleviates the severity of tonic and clonic muscular contractions which may cause fractures, dislocations and severe muscular pain. Proper oxygenation avoids severe hypoxia which is often associated with convulsions and which may have deletarious effects in old patients with poor myocardial reserve. Curare was formerly used for paralysing the muscles but its onset of action was slow and duration of effect was prolonged which is not desirable for very short procedures like ECT. Subsequently succinylcholine following induction with tbiopentone was chosen as its onset of action was quick; its effect, on an average, lasts for 2-3 minutes. The hang over effect and remarkably slow recovery from anaesthesia are the greatest drawbacks for its use especially in psychiatric patients receiving large doses of tranquillising drugs. With this objective in mind we studied Propanidid-a short and rapid acting intravenous anaesthetic agent and compared its actions with those of Thiopentone sodium in terms of their relative influence as regards the post-treatment physical arousal and recovery of cognitive functions in psychiatric patients receiving ECT. Effects on cardiovascular and respiratory systems and any untoward side effects were noted.
The study was conducted on 100 patients undergoing electro-convulsive therapy. Both indoor and outdoor patients of the Psychiatry department were included in the study. A thorough physical and systemic examination was done to assess the patient's status to undergo general anaesthesia. Routine investigations like haemoglobin, urine and X-ray chest were done. Patients were starved overnight and received Inj. Atropine 0.6 mg. I.M. half an hour before the procedure. Each patient entering the study received Propandid or Thiopentone sodium at random in an alternating sequence on successive treatment days. In the first sitting, Inj. Thiopentone sodium was administered as 2.5% solution in the dose range of 4-5 mg/kg. body weight at the rate of 1 ml/sec. In the second sitting, Propanidid was administered as 5% solution intravenously with a size No. 20 needle (without dilution) at the rate of 1 ml per 2 seconds in the dose range of 6-7 mg/kg. body weight. After induction muscular relaxation was achieved with succinylcholine 1.5 mg/kg. body weight with Thiopentone Sodium and 1 mg/kg after Propanidid. On an average, the muscular relaxation and apnoea lasted for 3-5 minutes. Throughout the trial a "Cinex Stim" ECT- unit not fitted with glissando was used. An output of 90-100 volts at 50 cycles per second (sine wave form) was given to each patient for 1-2 seconds. This technique was constant for all the patients. The ECT was administered through stainless steel bilateral electrodes 3 cms in diameter which were well covered with gauze over 1 cm thickness of sponge rubber. The electrodes were dipped in saline solution before being applied to the temporal region of each patient. An average of about 45 seconds elapsed between the completion of anaesthetic injection and the administration of ECT. During this period the patient was ventilated with oxygen. The following observations were made during induction, during the maintenance and during the immediate post-anaesthetic period. (1) The time taken for the loss of conciousness and the loss of reflexes. (2) Apnoea time. (3) The time taken for appearance of pain perception and reflexes. (4) The time taken for return to conciousness. (5) The complete recovery time was noted from the onset of loss of consciousness, till the time the patient regained consciousness, talked relevantly, was well oriented and able to sit and walk. (6) Changes in pulse rate and rhythm and blood pressure were recorded. (7) Evaluation of post ECT recovery of mental functions namely physical arousal and regaining of intellectual functions. In order to evaluate these two pertinent aspects in our study we empoyed a psychological assessment procedure which compiled a battery of brief verbal and performance tasks. The test sequence was graded to elicit an increasingly active intellectual performance from the recovering patients. The tasks which were employed were ordinarily within the competence of all patients. A brief description of psychological assessment procedure is as follows: (1) Physical arousal-Patient was instructed to open eyes with reinforcing stimulus of a light slap either on the back of his hand or shoulder. (2) Volitional motor response-Patient was requested to put out the tongue. (3) First verbal response-Patient was requested to tell his name. (4) Personal orientation-Patient was requested to tell his age, and present location. (5) Picture vocabulary-Patient was asked to identify objects like Pen, Note book, Wrist watch. (6) Patient was asked to sit upright in bed, without assistance. (7) General memory-Questions regarding family, education and job were asked at the pre-ECT interview of the patient and were confirmed from his relatives. The same questions were repeated after the patients regained consciousness to know whether they can remember correctly or they are confused.
The assessment of different parameters during the conduct of anaesthesia and recovery is given in [Table 1]. Effects on cardio-vascular system The blood pressure fluctuations were found to be minimal. The average range of rise or fall of blood pressure was 10-20 mms of Hg. All the patients in both the groups showed tendency towards tachycardia which averaged about 30-40 beats per minute except the four patients who were given propanidid showed tendency towards bradycardia, but did not need any treatment for it and returned to normal in a few seconds. No irregularity of pulse was recorded clinically [Table 2]. No changes in the blood pressure occurred in 20% cases with pentothal group and in 16% cases with propanidid group. The results of psychological assessment tests were as per [Table 3]. Some of the patients who received ECT were confused at the end of the procedure and the incidence of past-ECT confusional states was high in schizophrenic patients as compared to the patients with manic depression where the incidence was almost nil. This shows a definitive relationship between the diagnostic syndrome and post-ECT confusional state. After repeated sittings (about 5-6) the incidence of post-ECT confusional state became less. The side effects which we came across during the conduct of our study are enlisted in [Table 4]. The main venous complications with propanidid group were ecchymosis (subcutaneous discolouration) in 6 cases and phlebitis in 6 cases. Thrombosis in the lumen of vessels and thrombophlebitis did not occur. These minor venous complications may be due to repeated intravenous injections themselves. Mild involuntary movements of hands and feet were observed in a few patients but these ceased within a minute or two. Four patients had itching during the recovery phase 'probably because of the histamine release by propanidid. There were no other alarming allergic manifestations like severe hypotension or bronchospasm. Allergy and hypersensitivity after intravenous pentothal, though rare, is well known.
Electroconvulsive therapy plays an important role in modern psychiatry. The ambulatory psychiatric patients who are to undergo electro-convulsive therapy need an anaesthetic technique which provides optimal conditions during the actual procedure i.e. brief period of analgesia, anaesthesia, good muscular relaxation, avoidance of undue depression of cardiovascular and respiratory systems with quick and complete recovery at the end of the procedure. The hang over effect due to residua! effects of the anaesthetic drug still to be metabolised (redistributed to the tissues) is undesirable The patients once completely recovered should be in a state that they can be safely handed over to the relatives without any need for medical supervision. Reviewing the literature regarding the pharmacological effects of Propanidid we felt that this anaesthetic agent would fulfil all the requirements needed for a procedure like ECT with an added advantage over the conventionally used. Thiopentone sodium in that the mean recovery time is less than half, protective reflexes are good and there is no hang over effect after propanidid due to rapid breakdown of the drug in the body to inactive metabolites and absence of redistribution to tissues.[1], [4], [6],[10], [11] Propanidid has a rapid action. [10], [11] There is a linear relationship between its dose and duration of sleep though the duration does not increase in proportion to the dose.[4], [14], [16] Propanidid is not hepatotoxic.[1], [9] Certain pre-medicants having analgesic properties (e.g. Cyclizine, Hyoscine or Promethazine) increase the sensitivity to somatic pain after propanidid and thus increase the incidence of excitatory phenomenon in the form of involuntary movements of hands and feet.[5], [11] Hence, it is preferable to pre-medicate the patients only with atropine if they are to receive propanidid for minor surgery. With Thiopentone sodium the mean recovery is remarkably slow, return of protective reflexes not very satisfactory. The hang over effect after Thiopentone sodium is the main disadvantage especially in ambulatory outpatients. Propanidid a eugenol derivative produces rapid onset of unconsciousness, loss of reflexes and good muscular relaxation along with succinlylcholine. The severity of muscular fasciculations after Propanidid-suxamethonium sequence is less when compared with Thiopentone-suxamethonium sequence. The incidence of post suxamethonium pains is less in patients who receive propanidid than in those who receive Thiopentone sodium.[7],[13] Though it was expected that the Propanidid-suxamethonium sequence would result in an increase in the incidence of prolonged apnoea,[7], [8] to our surprise we did not come across a single case of prolonged apnoea when suxamethonium was used after induction with Propanidid. We reduced the dose of suxamethonium to two-thirds of the average dose used after thiopentone (1 mg/kg). The reduction in dosage of suxamethonium was also necessary keeping in mind that the quick recovery from propanidid would otherwise give rise to a very unsatisfactory state where the patients wake up but are unable to breathe because of muscular paralysis and feel very uncomfortable. There are reports on severe fall in blood pressure and cardiac arrest[1], [2], [11] either due to severe depression of myocardium by propanidid or due to massive release of histamine by the drug's giving rise to peripheral vasodilatation, peripheral pooling of blood, reduction in venous return and blood pressure. In our series the fall of blood pressure was within the acceptable range of 10-20 mm of Hg. and was accompanied by compensatory tachycardia. Similar results were obtained when Thiopentone was used as anaesthetic agent. The only allergic reaction which we have come across in our series is that 4 of our patients had itching all over the body during recovery. No alarming allergic menifestations like severe hypotension or bronchospasm were observed. Anaphylaxis after Thiopentone, though rare; is well known. There was a striking difference in psychological performance tests. The results are in favour of propanidid as an anaesthetic agent.. The post-ECT confusional state was more related to the diagnostic syndrome (more common in schizophrenic patients) than to the anaesthetic agent used. However, as given in literature with the use of propanidid there was a slightly higher incidence of minor venous complications like phlebitis and ecchymosis[3], [11], [12] probably because the solution used was more viscid and relatively larger size of needle was used. The incidence can be reduced by diluting the solution with equal volume of saline and using a small bore needle. The incidence of involuntary movements is also slightly higher after propanidid than after Thiopentone.[5],[11] This is minimal when only Inj. Atropine is used as a premedicant drug. However, these side-effects are of minor consequence when compared with delayed recovery after Pentothal and undesirable hang over effect. Thus in practical terms, the more rapid and complete recovery after propanidid anaesthesia reduced the need for prolonged nursing care and less number of nursing personnel are needed, in the running of an out patient ECT programme. The average duration by which an outpatient can safely leave the clinic is 10.-15 minutes with propanidid and 30-40 minutes after Thiopentone sodium.
Propanidid when compared with Thiopentone sodium as an anaesthetic agent for Electro-convulsive therapy proved superior to thiopentone. It had following advantages. (1) Propanidid provided rapid and complete recovery at the end of the procedures. The return of intellectual functions was good. Hong over effect was absent. (2) The incidence and severity of post suxamethonium pains was less. (3) No alarming anaphylactic reaction. However, the incidence of minor venous complications and involuntary movements is slightly higher after propanidid than after thiopentone sodium but this is of much less consequence.
We take this opportunity to thank the Dean, Dr. C. K. Deshpande, G.S. Medical College and K.E.M. Hospital and Dr. A. J. Dhruva, D.A., M.A.M.S., Professor and Head of the Department of Anaesthesiology, to allow us to use the hospital data to prepare and publish this paper.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||
