Technical considerations The treatment

The procedures of modified ECT, the use of anaesthesia, and physiological monitoring are well established. Patients are asked to take no food for 8 h before the treatment and to void before coming to the treatment room. Although the necessary physiological monitoring can be most readily done if the patient wears a hospital gown, it is acceptable for an outpatient to wear regular clothes, as long as all restrictive items are removed. After an intravenous line is established, the treatment electrodes are applied. For many years, we favoured right unilateral electrode placement, but having recognized that such treatments are not fully effective, we now favour bilateral temporal electrode placement. Recently, attention has been given to a bifrontal electrode placement that has an efficacy equal to that of bitemporal placement and fewer cognitive and memory effects/64)

So that seizure characteristics can be monitored, a blood pressure cuff is applied to a lower limb, and the cuff is inflated before the muscle relaxant is administered. Electromyogram electrodes are applied below the cuff to record evidence of the motor seizure. EEG electrodes are applied, usually one to the forehead and one to the mastoid.

Throughout the procedure, the patient is ventilated with pure oxygen through a face mask. An anticholinergic agent (atropine 1.0 mg or glycopyrrolate 0.2 mg) is administered through the intravenous line, followed by a barbiturate, usually methohexital (0.5-1.0 mg/kg), and then by succinylcholine (0.5-1.0 mg/kg). Etomidate, ketamine, and other barbiturates are alternative effective anaesthetics. We do not use propofol since it has been found to impede treatment efficacy. Atracurium and mivacurium are effective alternatives for succinylcholine.

The limb cuff is inflated above the systolic pressure before succinylcholine is administered, and the limb is checked for motor responses to painful stimuli or to a muscle stimulator. The patient is considered ready for the seizure when the motor responses are less noticeable. At this time, the anaesthetist applies the bite-bloc between the patient's teeth to protect tongue and teeth from the direct stimulation of the masseter muscles, which usually results in a sharp jaw clench. The chin is held tightly by the anaesthetist so that the patient will not open his or her mouth and disgorge the bite-bloc during the stimulation.

Energy dosing has become complicated. For most patients, an effective energy dose can be estimated by the half-age formula. (65> Since modern devices provide energies between 25 and 500 mC, graduated in 5 per cent steps, it is possible to set the initial energy at a percentage of 500 mC, estimated at half the patient's age. Some physicians use a full-age formula. Others recommend direct experimental estimates of the seizure threshold by an empirical process—applying a low amount of energy and doubling it in repeated stimulations, until a full grand mal seizure is observed. For subsequent treatments, the patient is usually treated at 1.5 or 2.0 times the observed threshold. Half-age estimates for energy selection are acceptable for treatments with bitemporal or bifrontal electrode placements, but a direct estimate of seizure threshold is considered necessary when unilateral electrodes are used. After determining the seizure threshold, we are not yet sure how to select the effective energy level. At 1.5 and 2.5 times the seizure threshold energy, treatments are ineffective. Two reports offer the possibility that the efficacy of unilateral electrode treatments can be equated to the efficacy of bitemporal ECT by increasing energy to six times the seizure threshold, but at this level the effects on memory and cognition are no longer spared and the advantages of unilateral ECT are lost. (6,67>

The physician has three guides to estimate the quality of the seizure. First, he or she should observe the motor seizure in the electromyogram. A duration of at least 25 s is an accepted minimum, except in the elderly. For them, we have to be satisfied with shorter durations of seizures, since these are often the best that can be obtained.

Next, the physician should note the increase in the heart rate. During the seizure, it will rise to 50 per cent above resting levels and fall quickly when the seizure is over. The duration of the heart rate increase is usually longer than that of the motor seizure.

Third, keeping in mind that the duration of the EEG seizure is usually between 30 and 120 s, the physician should adjust the energy dose for the second treatment if the first seizure did not evince the anticipated characteristic EEG phases. Occasionally, a seizure persists beyond 150 or 180 s. In such a case, intravenous diazepam (5 mg) is administered and repeated every 30 s until the seizure is over. During a prolonged EEG seizure, the motor activity and the heart rate provide no guide, so we rely on the EEG to protect against this complication. Some physicians recommend intravenous phenytoin, but such treatment is ineffective, since the anticonvulsant effect of phenytoin comes from high brain levels, and effective anticonvulsant levels are achieved in hours, not seconds; far too long to prevent damage from a very prolonged seizure. Others recommend repeated doses of the barbiturate used for anaesthesia, but the anticonvulsant properties of barbiturates are inferior to those of the benzodiazepines.

In a postseizure delirium, which occurs in about 10 per cent of the treatments, the patient is poorly aware of where he or she is and may thrash about and be confused. It is more common in the first and second treatments than in later ones. Reassurance, calm talk, and gentle handling of movements that might be harmful can usually allay such states. If the restlessness does pose risks, it can be calmed by intravenous diazepam or droperidol.

After treatment, hospital patients return to their rooms, where their behaviour is monitored until they are fully able to care for themselves. Many patients return to ward activities within 2 h; the elderly may require supervision for the day. Outpatients may leave the facility in the company of an adult caretaker as soon as they can walk easily. Although physicians try to limit the activities of their patients, it seems reasonable to stipulate that patients may do what they can do. That is, patients receiving outpatient ECT should be encouraged to participate in their normal activities with the supervision of their caretaker.

The ECT course

Occasionally a single treatment relieves a disorder, but such instances are so rare as to be noteworthy. The basic course is more often between six and 20 treatments. These are usually given three times a week at the onset and, after the symptoms show some relief, are reduced to twice or once a week. The resolution of catatonia is frequently accomplished in three to five treatments; depressive disorders require six to twelve. Manic and schizophrenic disorders may require series of 20 or more.

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