Three-quarters of deaths after surgery caused by circulation failure

• Postoperative mortality contributes to 7.7% of all deaths globally, making deaths because of surgical intervention the third leading cause of deaths worldwide after ischaemic heart disease and stroke.
• Such deaths are much more common in low- and middle-income countries (LMICs) - in the case of abdominal surgery, varying from 4.0% - 27.0% globally, depending on the patient’s baseline risk, need and urgency for surgery, and the operation performed.

Most patient deaths following abdominal surgery are caused by circulation failure, with sepsis accounting for almost two thirds of these, a new study reveals.

Almost three-quarters (73.6%) of post-operative deaths are due to circulatory system failure - including 173 deaths from septic shock (56.5%) and 30 deaths from hypovolaemic shock including bleeding (9.8%).

Death after surgery is the third leading cause of death around the world, and much more common in low- and middle-income countries (LMICs). There is currently no established typology for classification of death after surgery - a complex interaction between a patient’s underlying health and the stress of surgery. Researchers developed a new conceptual framework to standardise reporting and classification of postoperative mortality.

Backed by funding from the UK’s National Institute for Health and Care Research (NIHR), experts at the University of Birmingham led an international research team which studied 5,558 patients undergoing abdominal surgery, of which 3,704 operations (66.7%) were performed as an emergency.

The NIHR Global Health Research Unit on Global Surgery team discovered that a further 47 deaths (15.4%) were caused by respiratory failure. One in five (60) patients died without a clear cause of death. Most deaths occurred within 72-hours from surgery, and 19% of deaths occurred out-of-hospital, highlighting key areas for intervention.

Co-author Mr Sivesh Kathir Kamarajah, NIHR Doctoral Fellow at the University of Birmingham, commented: “Many factors contribute to death after surgery in LMICs, but reducing the number of patients dying requires intervention to address circulatory failure and sepsis.

“These interventions will be needed both in-hospital, and out-of-hospital where 1 in 5 postoperative deaths occur. These measures are likely to be complex but cannot be overburdensome to already stretched clinical services.

“With an ageing global population with increasing multimorbidity, postoperative mortality in likely to rise further across the next decade. If we are to design effective interventions to reduce mortality risk, we must improve understanding of why patients die after surgery.”

Culturally relevant interventions needed

The researchers note that work will be needed to ensure that interventions such as pre-optimisation, enhanced postoperative monitoring, and empowerment of family and carers are accessible, as well as contextually and culturally relevant.

National Surgical, Obstetric and Anaesthesia plans (NSOAPs) must be established alongside efforts to improve resourcing and resilience of perioperative systems, particularly in diagnostics, critical care, emergency surgery pathways and interventional radiology.

Co-author Ismail Lawani, Professor of Surgery at the University of Abomey-Calavi, Benin, commented: “With patients dying at different times, we must exploit opportunities to intervene throughout the treatment period, including after discharge. The high proportion of patients without a clear cause of death reflects the need to improve capacity to rescue by strengthening perioperative systems.”

There is currently no established typology for classification of death after surgery - a complex interaction between a patient’s underlying health and the stress of surgery. Researchers developed a new conceptual framework to standardise reporting and classification of postoperative mortality.