Sir,

Cancellation of cataract surgery on the day due to raised blood pressure (BP) is a great disappointment for the patient and, unless the slot can be refilled at the last minute, will cost the hospital the difference between the national tariff and the cost of consumables, ie, about £600. Raised BP during intraocular surgery is a risk factor for suprachoroidal haemorrhage and systemic vascular events. Surgeons will reasonably defer cataract surgery, when they consider the BP to be poorly controlled.

At our unit preoperative assessment is carried out by nurses over the telephone to save patients a separate hospital visit. Patients who have not had their BP checked within the preceding 3 months are asked to visit their general practitioner. On the day of surgery, if systolic BP >200 or diastolic >100 mmHg, despite a period of rest, patients under the care of one surgeon (TR) were given nifedipine 5 mg orally regardless of existing treatment (not sublingually), if they denied anxiety. Anxious patients are offered temazapam 10 mg.

Table 1 shows the BP recordings of 17 such patients over 27 months who were given nifedipine. The second reading of patients 4, 13, and 14 in Table 1 were marginally below the above thresholds but were included as nifedipine was still given. Surgery proceeded uneventfully in all 17 cases. These patients were among the 93% of cataract patients at this unit who have surgery without an anaesthetist present, ie, broadly those patients who are free of symptoms at rest, no acute vascular events within 3 months and including, for this surgeon, patients unable to lie flat.1 Full emergency medical support could have arrived within minutes if called. All patients were advised to have their BP treatment reviewed by their general practitioner.

Table 1 Blood pressure recordings (mmHg) before and 30 min after oral (not sublingual) nifedipine 5 mg
Full size table

Outside ophthalmology, the use of nifedipine preoperatively is not unusual. Weksler et al2 showed that intranasal nifedipine (10 mg) was safe to use for this purpose in 589 ‘controlled’ hypertensive patients with diastolic BP between 110 and 130 mmHg immediately before surgery. Swallowed nifedipine must lower BP more gradually and therefore be safer still.

The Royal College of Ophthalmologists guidelines state that hypertension should be controlled before the patient is scheduled for surgery.3 Nevertheless, there will always be poorly controlled patients on the day of surgery. Problems will admittedly be less frequent in eye departments with obligatory preoperative visits, but these have implications of cost and inconvenience. Nifedipine would have saved this hospital over £10 000, if these 17 patients had otherwise been cancelled without being replaced.