ECT Stimulus Dosing Protocol
Establishing Seizure Thresholds (ST) & Treatment Sessions
Introduction
Seizure Threshold (ST)...
be therapeutic whilst minimising cognitive side effects. In general this means that for
bilateral ECT the treatment dose s...
9

150 (75x2)

750

10

200

1000

First Treatment
Having decided at which level to begin, please consult appropriate titr...
•
•
•

Because of reduced cognitive side effects, measurement of the seizure
threshold may be less critical than for bilat...
Switching between unilateral and bilateral ECT
A switch from unilateral ECT to bilateral may be indicated if there is poor...
Bilateral treatment and increasing the stimulus dose has shown to be more effective
but produces more cognitive side effec...
Missed Seizures during Treatment
This is less likely to occur with unilateral ECT where the treatment dose is at least 4x
...
Appendix A

UNILATERAL ECT TREATMENT TABLE

Level

Titration Dose
Seizure Threshold
% (mC)

Treatment Dose
% Max (mC)

Hig...
Appendix B
BILATERAL ECT TREATMENT TABLE

Titration Dose
(Seizure
Threshold)
% (mC)

Treatment
Dose

High Dose (For
use in...
TITRATION SCHEDULE FOR PATIENT COMMENCING AT 5% BILATERAL
1ST Session

Fit

ST=5% Treat next session 10% B/L

5%
No Fit
In...
eco

TITRATION SCHEDULE FOR PATIENT COMMENCING AT 5% Unilateral
1ST Session

Fit

ST=5%

Treat at Next Session 20%

5%

No...
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Ect stimulus dosing protocol

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Transcript of "Ect stimulus dosing protocol"

  1. 1. ECT Stimulus Dosing Protocol Establishing Seizure Thresholds (ST) & Treatment Sessions Introduction Seizure Threshold (ST) is the lowest stimulus dose that produces an adequate seizure. Adequate seizure: generalised cerebral seizure activity associated with a tonic convulsion demonstrated by either • • EEG evidence of 3 per second spike and wave activity or Generalised, bilateral tonic-clonic motor activity The length of the seizure is not critical in determining the presence of an adequate seizure. The choice of laterality of treatment is the responsibility of the prescribing clinician. There is no “default setting” by the ECT team. The laterality of treatment also forms part of the consent process as patients need to be consented for unilateral or bilateral. Prescribing clinicians need to be aware of differences between unilateral and bilateral ECT. Unilateral ECT is less likely to cause cognitive side effects but higher suprathreshold doses are needed. Bilateral ECT is probably more effective in severe depression than unilateral. If a prescribing clinician has concerns as to choice of laterality then advice can be obtained from the lead consultant for ECT. Dose Titration The patient is given increasing doses of electrical stimulus until an adequate seizure is obtained. Once the seizure threshold is established, the treatment dose can be calculated 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 receive treatment doses, which are sufficiently in excess of the patient’s seizure threshold to 1
  2. 2. be therapeutic whilst minimising cognitive side effects. In general this means that for bilateral ECT the treatment dose should be 1½ to 2 times the seizure threshold and for 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 sex and electrode placement. Female unilateral Female bilateral Male unilateral Male bilateral level level level level 1 2 2 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 on Benzodiazepines or anticonvulsants, is dehydrated, has had ECT within the previous month, or other predictors of raised seizure threshold are present. (This does not apply if over 70 years) THYMATRON DOSAGE LEVELS Level mC Settings % 1 5 25 2 10 50 3 15 75 4 25 125 5 35 175 6 50 250 7 70 350 8 100 500 2
  3. 3. 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 second stimulation. If partial seizure or seizure of inadequate duration wait 30 seconds before proceeding to second stimulation. If still inadequate seizure, consider a third stimulation after 30 seconds. Do not proceed to a third stimulation without prior discussion with ECT Lead Consultant and Anaesthetist. Second Treatment Session Continue as per appropriate flowchart. If no seizure after first stimulation wait 30 seconds before proceeding to second stimulation. If partial seizure or seizure of inadequate duration wait 30 seconds before proceeding to second stimulation. However, do not proceed to a third stimulation without prior discussion with ECT Lead Consultant and Anaesthetist. Third and Subsequent Treatment Sessions Continue with calculated treatment dose but remember that seizure threshold may increase by up to 80% over a course of treatment. Because the patient’s clinical progress overrides all theoretical considerations, the above instructions can only be a guide, based on our present knowledge of ECT. If the patient is not responding to treatment it may be necessary to increase the dose by a greater percentage or to consider switching from unilateral to bilateral ECT. If the patient is experiencing marked cognitive side effects it may be necessary to switch to unilateral ECT, or space treatment sessions more widely, or reduce the treatment dose. The aim is to deliver effective treatment for each patient on each occasion. 1. For Unilateral ECT: ECT is given to the non-dominant hemisphere, usually the right, even in lefthanded patients. For left handed people, first measure seizure threshold with right unilateral ECT and in confusion occurs switch to left unilateral ECT next time. 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 is not paramount or those suffering from dementia. 3
  4. 4. • • • Because of reduced cognitive side effects, measurement of the seizure threshold may be less critical than for bilateral ECT. It may be necessary to change to bilateral ECT if there has been no beneficial effect after 4 unilateral ECT treatments. For unilateral ECT (when maintaining a wide difference between threshold and treatment doses is critical for efficacy), in the absence of significant cognitive side effects, increase treatment dose (in mC) by 5 – 10% at each subsequent treatment session 2. For Bilateral ECT: • • • • • This involves giving a dose of electricity approximately 1.5-2 times above seizure threshold using a bi-temporal electrode position. Most patients (75%) will have a seizure threshold (ST) below 100mC but there may be considerable variation between individuals so it is best to measure the ST. If there has been no clinical improvement after 4 apparently ‘adequate’ ECT treatments then increase the dose next time by 75-100mC, provided there have 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, who may therefore be at increased risk of cognitive side effects. If cognitive side-effects are troublesome: i) ii) reduce dose by 50mC OR 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 if there 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 threshold for any given individual. The seizure length is idiosyncratic and is not itself an indicator of efficacy. However as the course of treatment proceeds it may be necessary to increase the dose of electricity given to take account of the anticonvulsant action of ECT. A progressive shortening of the seizure may give some indication of this. The timing of the visible seizure is taken from the end of stimulation to the end of bilateral seizure activity. The seizure length as determined by the EEG will usually be 10-40% longer than the visible seizure; the relationship between these also tends to be idiosyncratic. There is good correlation between short EEG seizures and short visible seizures but the converse is not true; up to 6% of patients with a short visible seizure may be experiencing prolonged cerebral EEG activity. Such seizure activity should be terminated after 120 seconds. ECT machines are not directly comparable in terms of effect for a given total charge. 4
  5. 5. Switching between unilateral and bilateral ECT A switch from unilateral ECT to bilateral may be indicated if there is poor clinical response. A switch from bilateral to unilateral ECT may be indicated if there is significant cognitive impairment. In both cases the seizure threshold should be retitrated using the appropriate charts and the treatment dose calculated. If no seizure results or is inadequate in duration, the anaesthetist will further ventilate the patient. The patient may be re-stimulated after the anaesthetist has given approval. Restimulation should only occur in accordance with the Stimulus Dosing Protocol. • • • The treating doctor should also check their technique — in particular did they apply the electrodes firmly enough? In the event that the patient still does not fit after further stimulation in accordance with the Stimulus Dosing Protocol, then an entry should be made in the patient’s case-notes to bring the attention to the patient’s own psychiatric team. The psychiatric team may then wish to consider matters such as doses of drugs 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 further ventilate the patient. The patient may be re-stimulated after the anesthetist 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 they apply the electrodes firmly enough? In the event that the patient still does not fit after further stimulation in accordance with the Stimulus Dosing Protocol, then an entry should be made in the patient’s case-notes to bring the attention to the patient’s own psychiatric team. The psychiatric team may then wish to consider matters such as doses of drugs 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 anesthetics drug. Poor Clinical Response to ECT The clinical team should review patients who fail to respond within 4 to 6 treatment sessions. 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 is 6 x ST) or switching from unilateral to bilateral ECT. 5
  6. 6. Bilateral treatment and increasing the stimulus dose has shown to be more effective but produces more cognitive side effects. In some circumstances consideration may need to be given to changing the anaesthetic agent from Propofol to Etomidate (Propofol raises seizure threshold). This should be discussed with the clinical team involved (including RMO, ECT Lead Consultant and Anaesthetist) and clearly documented in the medical file/ECT care pathway. Procedure for Discontinuation of ECT The prescribing and discontinuation of ECT are the decision of the patients Consultants/RMO. However, the decision to discontinue ECT may also take place in the context of discussion with the ECT Consultant and/or Anaesthetist in the light of adverse 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 ECT session and treatment should be stopped when response has been achieved. A patient should not receive more treatments than is required to achieve an adequate response, even if more have been prescribed, hence the patient must be reviewed after each treatment during the treatment course. Recommendations from ECT Handbook: A set course of treatments should not be prescribed – the need for further treatments should be assessed after each individual treatment. Bilateral ECT If 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 ECT in patients who have shown definite but slight or temporary improvement with early treatments. Unilateral ECT For patients who do not respond to unilateral ECT, consideration should be given to switching 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 Anaesthetist Seizures lasting longer than 120 seconds (EEG) should be terminated using intravenous Diazepam, 5 – 20mgs given over a period of 10 – 20 seconds. 6
  7. 7. Missed Seizures during Treatment This is less likely to occur with unilateral ECT where the treatment dose is at least 4x the seizure threshold. When bilateral ECT is used the treatment dose is 1.5x the seizure threshold and it is possible that seizures may be missed due to increasing seizure threshold occurring during the course of ECT. If the patient fails to have a seizure, wait 30 seconds and re-instate and re-stimulate at 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 there is another missed seizure wait 30 seconds and repeat the procedure described above. Following two consecutive treatment sessions where there has been missed seizure, the treatment dose should be increased by one level. Clinical progress should 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 Anaesthetist During recovery, patients suffering from states of agitation associated with rhythmic or aimless repetitive movements or other evidence of gross confusion should be given intravenous Midazolam, 1 – 5 mgs slowly. In the case of recurring emergence delirium consideration should be given to routinely administering intravenous Midazolam 1 – 5mgs as soon as EEG seizure has terminated. In both situations patients will need extra oxygenation until they have fully regained consciousness. 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 7
  8. 8. Appendix A UNILATERAL ECT TREATMENT TABLE Level Titration Dose Seizure Threshold % (mC) Treatment Dose % Max (mC) High dose for use in 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) 70% (350) 200% (1000) 200% (1000) 100% (500) 200% (1000) 200% (1000) 9 150% (750) 200% (1000) 200% (1000) 10 200% (1000) 200% (1000) 200% (1000) 7 8 8
  9. 9. Appendix B BILATERAL ECT TREATMENT TABLE Titration Dose (Seizure Threshold) % (mC) Treatment Dose High Dose (For use in nonresponders) 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) Level 9
  10. 10. TITRATION SCHEDULE FOR PATIENT COMMENCING AT 5% BILATERAL 1ST Session Fit ST=5% Treat next session 10% B/L 5% No Fit Increase 3 Levels 25% No fit Increase 1 level 35% Fit D/W Lead Consultant prior to 2nd session. No Fit Fit Second Session nc Increase 1 Level Reduce 2 levels 10% ST= 35% Treat next session 55% B/L Fit ST= 10% Treat at next session 15% B/L 50% No Fit Increase 1 Level 15% Fit ST=50% Treat Next session 75% B/L No fit Increase to 70% ( or change anaesthetic agent as previously discussed.) 70% Fit No Fit ST=15% ST=25% Treat at next session Treat at This session 25% B/L 40% B/L Fit ST=70% Treat at Next Session 110% 10 No fit D/W Lead Consultant ? 100% ST = SEISURE THRESHOLD
  11. 11. eco 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% Fit ST=35% Treat 140% UNI. This session ST= 35% Assume ST= > 35% 2nd & subsequent Session 200% No Fit ST= 10% Treat at next session 40% Uni. Increase up 1 level 15% Fit ST=15% Treat as next session. 60% UNI. No Fit ST=25% Treat at This session 100% UNI. 11 ST=SEIZURE THRESHOLD
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