Only patients with BP below 160/100 should be referred for surgery to avoid cancellations, guidelines say

GPs should include information on a patient’s blood pressure (BP) in referral letters for elective surgery and should refer only those with BP lower than 160/100 mm Hg over the previous 12 months, say new guidelines that aim to reduce surgery cancellations due to high BP.1

Nearly 1% of planned surgery in the NHS is currently cancelled at the last minute, and hypertension is a common reason.

“Across the UK this equates to approximately 100 concerned and inconvenienced patients each day, with associated costs to the NHS and the national economy,” said the co-chair of the guideline working party, Andrew Hartle, who is a consultant anaesthetist at St Mary’s Hospital in London and president of the Association of Anaesthetists of Great Britain and Ireland.

The guidelines, developed jointly by the association and the British Hypertension Society, give national recommendations for the measurement, diagnosis, and management of raised BP in adults before planned surgery.

“There has previously been no consistency in what people do in deciding whether or not to go ahead with elective surgery on the basis of a patient’s blood pressure,” Hartle told The BMJ. “Patients arrive for surgery, are rushed through, have their blood pressure measured, and, if it’s high, some would be measured again—and some would have their surgery cancelled and be sent back to their GP.”

Terry McCormack, guideline party co-chair, who is a GP in Whitby and secretary of the British Hypertension Society, added, “Cut-offs for BP levels at which surgery was postponed varied between different areas of the country, different hospitals, and even different departments within hospitals.

“Often, a patient’s blood pressure has been measured in primary care and shown to be OK, but hospitals don’t know that. They take a measurement at a time when a patient is potentially stressed, when they are about to have surgery, and they base decisions on that.”

The guidelines aim to stop hospital staff diagnosing hypertension during preoperative assessments and basing decisions about whether to proceed with surgery on these potentially spurious BP measurements, and they encourage GPs to include information on a patient’s BP in referral letters for elective surgery.

Secondary care teams should accept patients for elective surgery if they have documented evidence in GP referral letters that the patient’s mean BP has been lower than 160 mm Hg systolic and 100 mm Hg diastolic over the previous 12 months, the guidance recommends.

Patients who do not have documented primary care BP measurements can undergo elective surgery if they had measurements below 180/110 mm Hg diastolic at readings made in preoperative assessment clinics, but they should be referred back to their GP for diagnosis and management of hypertension, the guidelines state.

In making their recommendations, the guideline committee recognised that BP measurements may be more accurate in primary care than in secondary care, as the environment tends to be less stressful for the patient and because staff have a more practised measurement technique. They noted that the guidelines apply only to patients referred for elective surgery and not to those requiring emergency surgery, cardiac surgery, or surgery for high BP, or to children and pregnant women.

The guideline working group said that improved communication between primary and secondary care is essential in reducing unnecessary last minute cancellations for elective surgery.

“There is currently huge variation in documenting blood pressure on referral letters,” said Hartle. “Moving to integrated electronic care records should help by standardising referrals, but we are still a long way from that.”

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