Case 3 Chase the bloods

Mrs Chung is a 59-year-old woman who has come to the emergency department because she feels very weak, is dizzy and at times has pins and needles in her hands. She reports that the weakness has been a gradually progressive problem over the last five days. Normally she is a very active lady who works long hours in her family business and her only past medical history is of oesophageal reflux and mild hypertension for which she takes omeprazole 20 mg a day and bendroflumethiazide 2.5 mg. She is anxious and the emergency department FY2 doctor who sees her thinks she is probably hyperventilating but asks the medical registrar on call to see her at 15.20 that afternoon.

What other diagnoses should be considered at this stage?

There is little to find on examination other than the observation that Mrs Chung does indeed appear weak and is unable to get out of bed without assistance. The medical team arrange some blood tests which show she has a sodium of 133 mmol/l, potassium of 2.9 mmol/l and a creatinine of 63 mmol/l. A diagnosis of weakness due to hypokalaemia is made and the bendroflumethiazide is discontinued.

Was this a reasonable assumption?

Mrs Chung is given intravenous saline with 40 mmol/l potassium and she is commenced on oral potassium replacement therapy and she is reassured and told she can probably go home the next morning if the repeat blood tests are better. Further investigations have been sent including an adjusted calcium which is phoned back by the laboratory later that evening to the ward – it is 1.2mmol/l. The staff nurse informs Dr Briggs, the on call house officer, who assumes this is an ionized (rather than an adjusted) calcium and takes no further action.

What should Dr Briggs have done?

Late the next morning the admitting team review Mrs Chung and are pleased to see that her potassium is now 3.5 mmol/l and they decide to send her home. Just before she goes the calcium result is noted and it is assumed that an error, perhaps of transcription, has occurred.

If it is believed an error has been made, is it reasonable to simply repeat the test?

A repeat blood test is sent at midday but the team are busy and no one looks out for it later that afternoon and so Mrs Chung goes home as arranged at 17.00. The result was on the laboratory computer by 13.30 (the repeat value is still 1.2 mmol/l and the laboratory have also done a magnesium which is reported as < 0.1 mmol/l) but the day team missed it and the evening team have not been alerted to the fact that these results are outstanding and so no action is taken.

The next day the medical registrar who admitted Mrs Chung sees the result but as these values are ‘lower than I have ever seen before – probably taken from the drip arm’ she rings Mrs Chung’s GP and asks if another sample can be sent just to be sure. When the practice nurse rings Mrs Chung that afternoon, she is answered by her husband who is very distressed and says his wife has just collapsed with a seizure. The ambulance is called and Mrs Chung is found to be in ventricular fibrillation. A prolonged resuscitation attempt ensues and she is brought back to hospital where she is given intravenous calcium and magnesium and makes a slow and difficult recovery. She has irreversible brain injury as a result of the circulatory arrest and although she eventually is able to go home she is unable to contribute to running the business and needs prompting and help with even the most basic tasks.

Expert opinion

Mrs Chung has a rare but well documented complication of her proton pump inhibitor therapy – hypomagnesaemic hypoparathyroidism, and it is perhaps not altogether surprising that this was not recognized at the outset. However the family make a claim against the hospital based on the fact that the cardiac arrest was preventable and that the results of investigations showing the dangerously low calcium level were available on the evening she was admitted but no appropriate action was taken. The delay in recognizing the problem was compounded by inadequate handover arrangements and the erroneous assumption that the calcium and magnesium concentrations were too low to be credible and must have been artefactual.

If an error is suspected an incident form should have been completed and the test result confirmed or refuted with the minimum of delay. In fact it would have been very quick and easy to check the calcium level on the blood gas analyser in the Emergency Department without waiting for formal laboratory estimation. When an investigation is requested it is the responsibility of the person(s) making the request to look out for and act as necessary on the result. With frequent shift changes, handover arrangements are crucial.

A related situation occurs with emergency chest X-rays which are likely to be seen and interpreted by non-radiologists during an emergency admission and a formal radiological report may not follow for some days, by which time the patient may well be ‘off the radar’ and have gone home. Incidental radiological findings unrelated to the initial presentation may well have been missed by a non-expert reporter (e.g. a small but suspicious nodule behind the first rib) and although a report exists, if no one is looking out for it then the next time it is read may be months later when the patient presents with an inoperable lung tumour. Safety nets must be put in place to ensure that abnormal findings are flagged up appropriately and are dealt with. It is not acceptable to assume that your responsibility automatically goes as you walk out of the hospital.

Legal comment

Assessment of liability with regard to breach of duty seems clear cut: individual human errors, caused by incorrect assumptions and by systems factors have resulted in Mrs Chung being discharged prematurely. The results of low calcium were known to Trust employees and if these test results had been recognized and acted on then, on the balance of probability, the cardiac arrest could have been prevented.

This is likely to be a high value quantum case with significant compensation awarded; both in terms of the extent of Mrs Chung’s ongoing care needs but also the loss of her value to the family business.

Mrs Chung has irreversible brain injury as a result of circulatory arrest. The family’s lawyers will need to submit evidence about the loss of income for the family business: for example, will the business now need to employ an extra person to do Mrs Chung’s work and has there been a reduction in profit and increase in outgoings as a result of her inability to work? Until what age would Mrs Chung ordinarily have been expecting to work? There will be quite considerable care requirements for Mrs Chung with assistance with personal care, activities of daily living and mobility. Independent expert reports will be required from nursing care, occupational therapy, and physiotherapy experts. Her family will have to consider adaptations to their current residential accommodation (or a possible move if this is unsuitable for the care requirements of Mrs Chung) for which they will also need to obtain expert evidence.

In some legal cases, where liability is fairly clear-cut, an early admission of liability by the NHSLA will result in judgment being entered and the focus of the legal case becomes the assessment of damages, i.e. quantum settlement. On the basis of an admission of liability, the patient’s solicitors will sometimes apply for an interim payment – so as to assist the family in the interim with essential and pressing care needs – rather than waiting for the final damages settlement.

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