What are the guidelines for referring patients with complex medical histories to an anaesthetist before surgery?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 16 August 2025Updated: 16 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

For patients with complex medical histories, specific guidelines indicate when an anaesthetist should be involved prior to surgery.

  • Direct Consultation for Cardiac Symptoms: If a patient has a heart murmur and any cardiac symptom (such as breathlessness, pre-syncope, syncope, or chest pain) or signs/symptoms of heart failure, a resting electrocardiogram (ECG) should be carried out, and the findings discussed with an anaesthetist before ordering a resting echocardiogram .
  • Consideration of Comorbidities in Anaesthetic Assessment: The American Society of Anesthesiologists (ASA) Physical Status Classification System is used to describe a person's fitness to undergo an anaesthetic . Anaesthetists in the UK often interpret these ASA grades in relation to functional capacity, specifically how comorbidity (complex medical history) limits a person's activity (e.g., ASA 3) . This implies that patients with significant comorbidities are assessed by anaesthetists as part of their fitness for surgery.
  • Information Sharing for Surgical Consultation: When referring people with diabetes for surgical consultation from primary care, their most recent HbA1c test results should be included in the referral information . This ensures relevant details of complex medical conditions are available for the surgical team, including anaesthetists.
  • Preoperative Assessment and Risk Stratification: For all surgeries, including those for patients with complex medical histories, a validated risk stratification tool should be used to supplement clinical assessment . The person's risks and surgical options should be discussed with them to facilitate informed shared decision-making . Enhanced recovery programmes, which include preoperative components, are offered for elective major or complex surgery .

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