High-risk surgical patients and shared decision-making

Contents

Overview

Approximately 10–15% of patients undergoing major surgery account for over 80% of postoperative deaths. This high-risk group requires systematic identification, honest risk quantification, multidisciplinary optimisation, and genuine shared decision-making before surgery proceeds. The intensivist increasingly plays a central role in this process — in preoperative assessment clinics, in perioperative optimisation protocols, and in the postoperative ICU care of those who develop complications.

Defining High-Risk Surgery

The Royal College of Surgeons and NICE define high-risk surgery broadly as any procedure carrying a predicted mortality of ≥5%, or a major complication rate of ≥10%.

High-risk procedures include:

  • Oesophagogastrectomy
  • Liver and pancreatic surgery (hepatectomy, Whipple procedure)
  • Major colorectal surgery (particularly emergency)
  • Aortic and major vascular surgery
  • Major urological surgery (cystectomy, radical prostatectomy with significant comorbidity)
  • Major orthopaedic surgery in elderly patients
  • Emergency laparotomy

Emergency surgery carries disproportionately higher risk than equivalent elective procedures — the NELA (National Emergency Laparotomy Audit) reports 30-day mortality of approximately 10% for all emergency laparotomies.

Patient factors also contribute: age, frailty, cardiorespiratory comorbidity, and functional limitation amplify procedural risk.

Preoperative Risk Assessment

Clinical Assessment

Cardiopulmonary exercise testing (CPET): Objective measurement of cardiorespiratory reserve. Patients cycle at increasing workload while expired gas is analysed. Key outputs:

  • Anaerobic threshold (AT): the point at which aerobic metabolism cannot meet demands and lactate begins to accumulate. AT <11 mL/kg/min is associated with higher perioperative risk.
  • Peak VO2: maximum oxygen consumption, reflects overall cardiorespiratory fitness.
  • VE/VCO2 slope: efficiency of ventilation; elevated values (>35) indicate inefficient gas exchange and higher risk.

CPET is considered the gold standard for objective functional assessment before high-risk surgery. It does not predict risk alone — results must be interpreted in clinical context.

6-minute walk test: Simpler, less resource-intensive measure of functional capacity. Distance <300 m is associated with higher risk.

Duke Activity Status Index (DASI): Patient-reported functional capacity questionnaire, expressed in metabolic equivalents (METs). Less than 4 METs indicates poor functional reserve.

Risk Scoring Tools

P-POSSUM (Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity): Calculates predicted morbidity and mortality from physiological variables and operative severity. Widely used for audit and consent. May underestimate risk in very high-risk patients.

SORT (Surgical Outcome Risk Tool): Uses ASA grade, urgency, severity, and operative category to predict 30-day mortality.

E-PASS: Estimates surgical risk from physiological and operative variables.

NELA score: Validated specifically for emergency laparotomy; uses age, ASA, urgency, presence of malignancy, soiling of the peritoneum, and physiological variables.

Functional Assessment and Frailty

Frailty is increasingly recognised as an important predictor of perioperative outcome, independent of comorbidity and surgical severity.

Clinical Frailty Scale (CFS): 9-point scale from very fit (1) to terminally ill (9), assessed by clinical history and observation. CFS ≥5 (mildly frail) is associated with significantly higher postoperative mortality.

PRISMA-7, Edmonton Frail Scale: Validated screening tools for frailty in the surgical population.

Perioperative Optimisation

Where possible, time before surgery should be used to reduce modifiable risk.

Anaemia: Anaemia is an independent risk factor for perioperative morbidity. Iron deficiency should be corrected pre-operatively — IV iron infusion provides faster response than oral iron and is appropriate when surgery is within 4–6 weeks. Erythropoiesis-stimulating agents have a role in specific situations.

Prehabilitation: Structured exercise, nutritional, and psychological preparation. Reduces pulmonary complications and hospital length of stay, particularly in patients with reduced baseline fitness.

Smoking cessation: Reduces pulmonary complications. Benefits accrue within 4–8 weeks of cessation.

Alcohol reduction: Reduces wound complications, bleeding, and cardiac complications if reduced by 4 weeks preoperatively.

Nutritional optimisation: Malnutrition is common in surgical patients and worsens outcomes. Oral nutritional supplements for 7–14 days preoperatively improve outcomes in malnourished patients.

Cardiac optimisation: Beta-blockade in established ischaemic heart disease. Statin therapy. Pacemaker or ICD review before surgery.

Respiratory optimisation: Maximise bronchodilator therapy in COPD; physiotherapy; treat active infection.

Shared Decision-Making

Shared decision-making (SDM) is the process by which the clinical team and the patient make healthcare decisions together, based on the patient's values and preferences alongside clinical evidence. It is now considered both an ethical requirement and a legal standard (Montgomery v Lanarkshire Health Board [2015] UKSC 11).

The Montgomery ruling established that doctors must disclose all material risks of a proposed procedure — defined as risks that a reasonable person in the patient's position would want to know, or that the particular patient would want to know. This is a patient-centred standard, replacing the previous Bolam test (what a reasonable body of medical opinion would disclose).

Elements of effective SDM in high-risk surgery:

  1. Information: Provide clear, quantified risk information (absolute risks, not just relative risks). Use decision aids and patient-friendly risk communication tools.
  2. Deliberation: Allow time for the patient to process information, ask questions, and discuss with family. SDM is a process, not a single conversation.
  3. Patient values: Explore what matters most to the patient — functional independence, pain control, cancer cure, returning to specific activities. What is their acceptable quality of life? What would they consider a worse outcome than death?
  4. Alternatives: Always present non-surgical options — conservative management, palliative care, delayed surgery. Surgery is not the only choice.
  5. Decision: The final decision belongs to the patient with capacity. Clinicians advise; patients decide.

In high-risk surgery, the goal of SDM is to ensure patients make informed decisions that align with their values. For some patients, a 20% mortality risk for surgery offering a 60% chance of cure is acceptable. For others — particularly those with severe frailty or pre-existing low quality of life — it is not.

The Consent Process

Informed consent requires:

  • A patient with capacity (assess and document)
  • Provision of relevant, accurate risk information (including mortality, specific complications, anaesthetic risks, blood products, ICU admission)
  • Time for questions and deliberation
  • A voluntary decision
  • Documentation

Risk should be communicated in absolute terms and tailored to the individual patient's calculated risk. "1 in 10 patients with your condition and operation has a serious complication" is more meaningful than "10% complication rate."

Consent for high-risk surgery should always include a discussion about ceiling of care and what the patient would want if complications occur — including their wishes regarding CPR, reintubation, and prolonged ICU care.

ICU Planning

All patients undergoing high-risk surgery should have a planned ICU or HDU admission post-operatively, confirmed before the day of surgery. Day-of-surgery cancellation due to lack of beds is associated with increased mortality.

The ICU team should be involved preoperatively:

  • Attend high-risk surgical MDT meetings
  • Review the patient preoperatively if complex perioperative decisions are anticipated
  • Agree monitoring plan, vasopressor strategy, and post-operative targets
  • Communicate ICU bed requirements to bed management in advance

Post-operatively, the ICU team should maintain an up-to-date ceiling-of-care discussion with the patient and family, given the clinical trajectory.

Viva Questions

How do you assess and quantify perioperative risk in a high-risk surgical patient?

Perioperative risk assessment integrates patient-specific factors, surgical factors, and urgency. For patient factors, I would assess functional capacity objectively — ideally with CPET, which provides an anaerobic threshold, peak VO2, and VE/VCO2 slope. An AT below 11 mL/kg/min identifies patients at higher risk. In centres without CPET, the DASI or 6-minute walk test provides a surrogate. Frailty is assessed using the Clinical Frailty Scale — frailty of CFS ≥5 is independently associated with higher mortality. I would quantify risk using a validated risk tool: P-POSSUM for elective major surgery, SORT for cross-specialty comparison, and NELA score specifically for emergency laparotomy. Comorbidity and organ function should be formally assessed — cardiac risk using ESC guidelines (functional capacity, specific cardiac conditions, ECG, echo where indicated) and respiratory reserve. The resulting risk estimate should be expressed as an absolute probability of mortality or major complication and used as the basis for the SDM discussion.

What did the Montgomery ruling establish and how does it change clinical practice?

The Montgomery v Lanarkshire Health Board ruling (UK Supreme Court, 2015) established that the standard for disclosure of risk in consent is determined by what a reasonable person in the patient's position would want to know, or what this particular patient would want to know — not what a reasonable body of medical opinion would disclose. This replaced the Bolam standard that had previously governed consent. In practice, this means clinicians must disclose all material risks, including those that are uncommon or rare but would be significant to this patient, and must not omit information based on an assessment that the patient might refuse treatment if fully informed. It also means the clinician must take into account the patient's specific circumstances and values when deciding what to disclose. The ruling reinforces SDM: the patient has the right to make an informed decision based on complete information about risks, benefits, and alternatives. For high-risk surgery, this means providing quantified risk estimates tailored to the patient, discussing non-surgical alternatives, and documenting the conversation thoroughly.

A 78-year-old man with a CFS score of 6 requires emergency surgery for a perforated sigmoid colon. How do you approach the consent and decision-making process?

This is a high-risk situation requiring rapid but genuine shared decision-making. I would calculate his predicted mortality using the NELA score or P-POSSUM — with frailty CFS 6, peritonitis, and advanced age, operative mortality may be 30–50% or higher. I would present this to the patient and family clearly and in understandable terms, alongside the alternative: non-operative management, which avoids surgery but does not treat the source and carries near-certain death from uncontrolled peritonitis. I would ask him what he values most — whether he prioritises any chance of survival, or whether the quality of that survival matters equally. I would explore his pre-existing quality of life: what was he able to do before this admission? What would he consider an unacceptable functional outcome? I would involve the surgical, anaesthetic, and ICU teams in a brief but structured multidisciplinary conversation. If he proceeds to surgery, we must agree the ceiling of care: what organ support is consistent with his values? Would he want prolonged mechanical ventilation and dialysis if the surgical outcome is poor? These questions must be asked and documented before he is anaesthetised. If he lacks capacity, I would apply the best interests standard under the MCA 2005.