Jump to perioperative management of potassium
Edinburgh: some of these protocols are specific to Edinburgh, but most are general.
In order to preven problems arising please consider the following:
- Patients being admitted for surgery should usually be admitted on the morning of the day prior to surgery. This will enable adequate time for the SHOs to admit the patient, and identify any problems which require to be addressed prior to surgery. This will also mean that the anaesthetist will be able to see the patient and be aware of any potential anaesthetic problems. Patients should not be advised to come for surgery on the afternoon or evening of the day prior to surgery
- If we think there is a case for day-case surgery, then this should be discussed with the anaesthetist and a clear protocol arranged
- If on dialysis, then some reorganisation of the dialysis schedule may well be required. For haemodialysis, arrangements should be made for the patient to have dialysis on the day before surgery. The plan should be put in writing with copies to the Dialysis Unit and Ward doctors (if to be an in-patient)
- Urea and electrolytes, creatinine, and a full blood count should be done on the morning of admission so that results are available for the anaesthetist when they assess the patient. In addition, for HD patients (or APD or CAPD if dialysis has been interrupted) urea and electrolytes should be done urgently, as early as possible, on the morning of surgery and these results should be sent with the patient to theatre
- If hyperkalaemia is anticipated, and since patients may be fasted overnight, there is a reasonable case for giving a slow dextrose infusion overnight and for some patients a single dose of calcium resonium on the evening prior to surgery. If hyperkalaemia is anticipated, proper planning avoids a crisis on the morning of surgery: see below
- In patients with ESRF, veins are precious and we should avoid siting i.v. cannulae in veins which may be used for future vascular access – this applies particularly to the cephalic vein in the forearm, see ‘Veins and vascular access. Clearly if a patient is going for vascular access procedure, then cannulae should not be placed in the arms being used for access
- Postoperatively, remember problems with prescribing of analgesics, especially NSAIDs and opiates, in different patient groups. There is a specific protocol for management of epidurals and patient-controlled analgesia (PCA, using fentanyl) in renal failure
The objective is to ensure that [K+] is below 5mmol/l. Post-dialysis [K+] should be checked at least 5 minutes after the end of dialysis. It should be well below 5.0 if possible (but in the normal range). This may necessitate arranging dialysis two days running, in patients who are frequently hyperkalaemic.
This may be too high for some types of surgery – eg prolonged, or likely to involve too much blood loss. If acceptable (discuss with anaesthetist), use the following maintenance regimen to prevent a further rise:
- infuse 10% dextrose at 40ml/h (without insulin in non-diabetic patients)
- give nebulised Salbutamol 5mg 6-hourly
If there is much delay, recheck [K+]
If it is 5.5-6.5:
This is likely to indicate a need for further dialysis pre-operatively – and should have been avoided. If surgery is to go ahead.
- give 50mls 50% dextrose with 5u Actrapid over 15 minutes
- follow with maintenance regimen above
Such decisions will normally be made at a senior level.
If it is over 6.5:
Dialysis is indicated except in an emergency. The relative risks then have to be judged.
Potassium should be checked after the patient returns. This may bot be necessary if potassium was under 5.0 pre-operatively, and the patient has had superficial surgery carried out under local anaesthesia, with insignificant blood loss.
Acknowledgements: Liam Plant was the original main author for this page. It was last updated by Caroline Whitworth and Neil Turner November 2006. The last modified date is shown in the footer.