ect stimulus dosing protocol-2

8/11/2019 ECT Stimulus Dosing Protocol-2

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ECT Stimulus Dosing Protocol

Establishing Seizure Thresholds (ST) & Treatment Sessions

Introduction

Seizure Threshold (ST) is the lowest stimulus dose that produces an adequateseizure.

Adequate seizure: generalised cerebral seizure activity associated with a tonic

convulsion demonstrated by either

EEG evidence of 3 per second spike and wave activityor

Generalised, bilateral tonic-clonic motor activity

The length of the seizure is notcritical in determining the presence of an adequateseizure.

The choice of laterality of treatment is the responsibility of the prescribingclinician. There is no default setting by the ECT team.

The laterality of treatment also forms part of the consent process as patients need tobe consented for unilateral or bilateral.

Prescribing clinicians need to be aware of differences between unilateral and bilateralECT. Unilateral ECT is less likely to cause cognitive side effects but highersuprathreshold doses are needed. Bilateral ECT is probably more effective in severedepression than unilateral.

If a prescribing clinician has concerns as to choice of laterality then advice can beobtained from the lead consultant for ECT.

Dose Titration

The patient is given increasing doses of electrical stimulus until an adequate seizureis obtained. Once the seizure threshold is established, the treatment dose can becalculated from the appropriate chart and used in subsequent treatment stimulations(see appropriate Titration Schedule) .

Most patients are expected to have a seizure threshold below 100mc (20%)and will be successfully titrated within two sessions.

The purpose of stimulus dosing is to ensure that patients subsequently receivetreatment doses, which are sufficiently in excess of the patients seizure threshold to


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be therapeutic whilst minimising cognitive side effects. In general this means that forbilateral ECT the treatment dose should be 1 to 2 times the seizure threshold andfor unilateral ECT at least 4 times the seizure threshold.

First Treatment Session

Decide on which level to proceed. Start at the following dose levels according to sexand electrode placement.

Female unilateral level 1Female bilateral level 2Male unilateral level 2Male bilateral level 2

In addition to above:

1. Increase by one level if patient is over 50, by 2 levels if over 70

2. Under the age of 70 Increase by a further one level if the patient is onBenzodiazepines or anticonvulsants, is dehydrated, has had ECT within the previousmonth, or other predictors of raised seizure threshold are present.(This does notapply if over 70 years)

THYMATRON DOSAGE LEVELS

Level

mC

1 5 25

2 10 50

3 15 75

4 25 125

5 35 175

6 50 250

7 70 350

8 100 500


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9 150 (75x2) 750

10 200 1000

First Treatment

Having decided at which level to begin, please consult appropriate titration schedule.If no seizure after first stimulation, wait 20-30 seconds before proceeding to secondstimulation. If partial seizure or seizure of inadequate duration wait 30secondsbefore proceeding to second stimulation. If still inadequate seizure, consider a thirdstimulation after 30 seconds.

Do not proceed to a third stimulation without prior discussion with ECT LeadConsultant and Anaesthetist.

Second Treatment Session

Continue as per appropriate flowchart. If no seizure after first stimulation wait 30seconds before proceeding to second stimulation. If partial seizure or seizure ofinadequate duration wait 30 seconds before proceeding to second stimulation.

However, do not proceed to a third stimulation without prior discussion with ECTLead Consultant and Anaesthetist.

Third and Subsequent Treatment Sessions

Continue with calculated treatment dose but remember that seizure threshold mayincrease by up to 80% over a course of treatment.

Because the patients clinical progress overrides all theoretical considerations, theabove instructions can only be a guide, based on our present knowledge of ECT. Ifthe patient is not responding to treatment it may be necessary to increase the doseby a greater percentage or to consider switching from unilateral to bilateral ECT. Ifthe patient is experiencing marked cognitive side effects it may be necessary toswitch to unilateral ECT, or space treatment sessions more widely, or reduce thetreatment dose.

The aim is to deliver effective treatment for eachpatient on eachoccasion.

1. For Unilateral ECT:

ECT is given to the non-dominant hemisphere, usually the right, even in left-handed patients. For left handed people, first measure seizure threshold withright unilateral ECT and in confusion occurs switch to left unilateral ECT nexttime. Do not increase dose until sure of laterality. The seizure threshold is less than for bilateral ECT. The effective dose of electricity is between 5-8 times seizure threshold. Even at high doses the cognitive side effects are negligible so this is presently

the treatment of choice for young people, patients where speed of response isnotparamount or those suffering from dementia.


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Because of reduced cognitive side effects, measurement of the seizurethreshold may be less critical than for bilateral ECT.

It may be necessary to change to bilateral ECT if there has been no beneficialeffect after 4 unilateral ECT treatments.

For unilateral ECT (when maintaining a wide difference between thresholdand treatment doses is critical for efficacy), in the absence of significantcognitive side effects, increase treatment dose (in mC) by 5 10% at eachsubsequent treatment session

2. For Bilateral ECT:

This involves giving a dose of electricity approximately 1.5-2 times aboveseizure threshold using a bi-temporal electrode position.

Most patients (75%) will have a seizure threshold (ST) below 100mC butthere may be considerable variation between individuals so it is best tomeasure the ST.

If there has been no clinical improvement after 4 apparently adequate ECTtreatments then increase the dose next time by 75-100mC, provided therehave been no cognitive side effects.

It is vital to record any post treatment confusion because this is an indication

that the dose of electricity has been too high for that particular patient, whomay therefore be at increased risk of cognitive side effects.

If cognitive side-effects are troublesome:

i) reduce dose by 50mC ORii) consider high dose unilateral ECT

For bilateral ECT (which has some effect even at the slightly supra-threshold doses)it is usually sufficient to increase the dose only if there is poor clinical progress or ifthere is a marked deterioration in the quality of the EEG seizure or motor fit.

For all treatments:

Both efficacy and side effects increase with the dose above seizure thresholdfor any given individual.

The seizure length is idiosyncratic and is notitself an indicator of efficacy.

However as the course of treatment proceeds it may be necessary toincrease the dose of electricity given to take account of the anticonvulsantaction of ECT. A progressive shortening of the seizure may give someindication of this.

The timing of the visible seizure is taken from the end of stimulation to theend of bilateral seizure activity.

The seizure length as determined by the EEG will usually be 10-40% longerthan the visible seizure; the relationship between these also tends to beidiosyncratic.

There is good correlation between short EEG seizures and short visibleseizures but the converse is nottrue; up to 6% of patients with a short visibleseizure may be experiencing prolonged cerebral EEG activity. Such seizureactivity should be terminated after 120 seconds.

ECT machines are not directly comparable in terms of effect for a given totalcharge.


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Switching between unilateral and bilateral ECT

A switch from unilateral ECT to bilateral may be indicated if there is poor clinicalresponse. A switch from bilateral to unilateral ECT may be indicated if there issignificant cognitive impairment. In both cases the seizure threshold should be re-titrated using the appropriate charts and the treatment dose calculated. If no seizureresults or is inadequate in duration, the anaesthetist will further ventilate the patient.The patient may be re-stimulated after the anaesthetist has given approval. Re-stimulation should only occur in accordance with the Stimulus Dosing Protocol.

The treating doctor should also check their technique in particular did theyapply the electrodes firmly enough?

In the event that the patient still does not fit after further stimulation inaccordance with the Stimulus Dosing Protocol, then an entry should be madein the patients case-notes to bring the attention to the patients ownpsychiatric team.

The psychiatric team may then wish to consider matters such as doses ofdrugs with anti-convulsant effects. At the next treatment it will be desirable to:-

- Pay special attention to stimulation technique- Adjust the stimulus strength in accordance with the Stimulus Dosing

Protocol- The anesthetist may wish to alter the dosages of anesthetic drugs

What if the patient does not have an adequate seizure

If no seizure results or is inadequate in duration, the anesthetist will furtherventilate the patient. The patient may be re-stimulated after the anesthetist hasgiven approval. Re-stimulation should only occur in accordance with the StimulusDosing Protocol.The treating doctor should also check their technique in particular did theyapply the electrodes firmly enough?In the event that the patient still does not fit after further stimulation in accordancewith the Stimulus Dosing Protocol, then an entry should be made in the patientscase-notes to bring the attention to the patients own psychiatric team.The psychiatric team may then wish to consider matters such as doses of drugswith anti-convulsant effects. At the next treatment it will be desirable to: -

- Pay special attention to stimulation technique- Adjust the stimulus strength in accordance with the Stimulus Dosing

Protocol- The anesthetist may wish to alter the dosages of anesthetics drug.

Poor Clinical Response to ECT

The clinical team should review patients who fail to respond within 4 to 6 treatmentsessions. Consideration should be given to increasing the treatment stimulus to the

higher dose (for bilateral ECT this is approximately 2.5 x ST, for unilateral ECT this is6 x ST) or switching from unilateral to bilateral ECT.


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Bilateral treatment and increasing the stimulus dose has shown to be more effectivebut produces more cognitive side effects. In some circumstances consideration mayneed to be given to changing the anaesthetic agent from Propofol to Etomidate(Propofol raises seizure threshold). This should be discussed with the clinical teaminvolved (including RMO, ECT Lead Consultant and Anaesthetist) and clearlydocumented in the medical file/ECT care pathway.

Procedure for Discontinuation of ECT

The prescribing and discontinuation of ECT are the decision of the patientsConsultants/RMO. However, the decision to discontinue ECT may also take place inthe context of discussion with the ECT Consultant and/or Anaesthetist in the light ofadverse reactions to ECT such as cognitive problems or anaesthetic problems.

Discontinuation may also take place because of poor efficacy or, most importantly,because the patient has withdrawn consent.

The clinical status of a patient should always be assessed between each ECTsession and treatment should be stopped when response has been achieved.

A patient should not receive more treatments than is required to achieve an adequateresponse, even if more have been prescribed, hence the patient must be reviewedafter each treatment during the treatment course.

Recommendations from ECT Handbook:

A set course of treatments should not be prescribed the need for further treatmentsshould be assessed after each individual treatment.

Bilateral ECTIf no clinical improvement at all is seen after six properly-given-bilateral treatments,then the course should be abandoned.

It may be worth continuing up to twelve bilateral treatments before abandoning ECTin patients who have shown definite but slight or temporary improvement with earlytreatments.

Unilateral ECTFor patients who do not respond to unilateral ECT, consideration should be given toswitching to bilateral treatment. It will be necessary to re-titrate seizure threshold in

this case

Procedure for Prolonged Convulsion Tardive seizures

To be discussed with the AnaesthetistSeizures lasting longer than 120 seconds (EEG) should be terminated usingintravenous Diazepam, 5 20mgs given over a period of 10 20 seconds.


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Missed Seizures during Treatment

This is less likely to occur with unilateral ECT where the treatment dose is at least 4xthe seizure threshold. When bilateral ECT is used the treatment dose is 1.5x theseizure threshold and it is possible that seizures may be missed due to increasingseizure threshold occurring during the course of ECT.

If the patient fails to have a seizure, wait 30 seconds and re-instate and re-stimulateat the next available treatment dose. A further treatment (of one incremental step)may be indicated after discussion with the Anaesthetist, if again there is no seizure.

At the next session revert back to the previously calculated treatment dose. If thereis another missed seizure wait 30 seconds and repeat the procedure describedabove. Following two consecutive treatment sessions where there has been missedseizure, the treatment dose should be increased by one level. Clinical progressshould be monitored and consideration given to switching to high dose ECT(calculated from the original seizure threshold) if there is insufficient improvement.

Procedure for Emergence Delerium

To be discussed with the AnaesthetistDuring recovery, patients suffering from states of agitation associated with rhythmicor aimless repetitive movements or other evidence of gross confusion should begiven intravenous Midazolam, 1 5 mgs slowly.

In the case of recurring emergence delirium consideration should be given toroutinely administering intravenous Midazolam 1 5mgs as soon as EEG seizure

has terminated.

In both situations patients will need extra oxygenation until they have fully regainedconsciousness. Need to discuss with Anaesthetist.

The above procedures will be reviewed in light of clinical research

Refs: The ECT Handbook, second edition, 2005. Royal College of Psychiatrists.McColl & Sackeim, Archives Gen Psychiatry May 2000. vol 57, 438-444.Mayur PM et al 1999 Brit J Psych. 174:270-2


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Appendix A

UNILATERAL ECT TREATMENT TABLE

Level Titration DoseSeizure Threshold

% (mC)

Treatment Dose% Max (mC)

High dose for usein non responders

% (mC)

1 5% (25) 20% (100) 30% (150)

2 10% (50) 40% (200) 60% (300)

3 15% (75) 60% (300) 90% (450)

4 25% (125) 100% (500) 150% (750)

5 35% (175) 140% (700) 200 % (1000)

6 50% (250) 200% (1000) 200% (1000)

770% (350) 200% (1000) 200% (1000)

8100% (500) 200% (1000) 200% (1000)

9 150% (750) 200% (1000) 200% (1000)

10 200% (1000) 200% (1000) 200% (1000)


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Appendix B

BILATERAL ECT TREATMENT TABLE

LevelTitration Dose

(Seizure

Threshold)% (mC)

Treatment

Dose

High Dose (Foruse in non-

responders)

1 5% (25) 10% (50) 15% (75)

2 10% (50) 15% (75) 25% (125)

3 15% (75) 25% (125) 40% (200)

4 25% (125) 40% (200) 65% (325)

5 35% (175) 55% (275) 75% (375)

6 50% (250) 75% (375) 130% (650)

7 70% (350) 110% (550) 190% (950)

8 100% (500) 150% (750) 200% (1000)

9 150 (750)

(75x2)

200% (1000) 200% (1000)

10 200% (1000)(100x2)

200% (1000) 200% (1000)


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TITRATION SCHEDULE FOR PATIENT COMMENCING AT 5% BILATERAL

1ST

Session

Fit ST=5% Treat next session 10% B/L5%

No Fit

Increase 3 Levels

25%

No fit

Increase 1 level

35%

D/W Lead Consultant prior to

2nd

session.

Fit Fit No Fit

Second SessionIncrease 1 Level

Reduce 2 levels

10% ST= 35% 50%Treat next session 55% B/L

No fit Increase to 70%

Fit No Fit ( or change anaesthetic

ST= 10% agent as previously

Treat at next session discussed.)

15% B/L Increase 1 Level Fit 70%

ST=50%

15% Treat Next session

75% B/L

Fit No Fit

ST=15% ST=25%

Treat at next session Treat at This session

25% B/L 40% B/L

Fit No fit

ST=70% D/W LeadTreat at Next Consultant

Session 110% ? 100%

ST = SEISURE THRESHOLD


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TITRATION SCHEDULE FOR PATIENT COMMENCING AT 5% Unilateral

1ST

Session Fit ST=5% Treat at Next Session 20%

5%

No Fit

Increase 3 Levels

25%

No Fit

Increase 1 level

35%

Fit Fit No Fit

2ND

Session

Reduce 2 levels

10% ST=35%

Treat 140% UNI. ST= 35%

This session Assume ST= > 35% 2nd

& subsequent

Session 200%

Fit No Fit

ST= 10% Increase up 1 levelTreat at next session

40% Uni. 15%

Fit No Fit

ST=15% ST=25%

Treat as next session. Treat at This session

60% UNI. 100% UNI.

ST=SEIZURE THRESHOLD


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