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Improved management of deteriorating patients with surgical complications has reduced the number of deaths in US hospitals rather than it being due to fewer complications. Over the past 10 years, complication rates have remained fairly similar. It is the reduction in 'failure to rescue' that has made the main difference in mortality. It is unclear if this is because of earlier detection of patients who are deteriorating due to complications, or improved response and treatment.

This large observational study tracked mortality, rates of serious complications, and failure to rescue of over 700,000 older adults following major surgery in Medicare hospitals.

These US findings support the recently introduced early warning system in the NHS called NEWS2. This aims to detect which patients are deteriorating so that management can be escalated. This is a hospital-wide initiative for all adult patients, not just following surgery.

Why was this study needed?

Surveys estimate that a third of potentially preventable deaths in the UK are due to inadequate clinical monitoring. Patients recovering from major surgery are at particularly high risk of sudden deterioration.

An earlier review suggested that junior staff may take physiological measurements but may not be aware of their meaning and that hospital hierarchy was a barrier to calling rapid response teams.

Though overall deaths after major surgery have reduced in recent years, there is still some variation between hospitals. This study aimed to identify which factors could help improve mortality rates at poorer performing hospitals.

What did this study do?

This retrospective cohort study used US national data from Medicare, the federal health insurer. It included 702,268 people older than 65 years who had specific surgery in 3,404 hospitals from 2005 to 2014. Operations of interest were repair of abdominal aortic aneurysm, or removal of part or all of the colon, lung or pancreas. These types of surgery were chosen because they are common operations with high risk of adverse events.

The study looked at changes over time in mortality within 30 days of surgery and complications. If patients died after having at least one major complication, this was called failure to rescue.

This large study used a robust set of national data. However, differences in the demographics and healthcare provision in the US and UK may limit its applicability.

What did it find?

  • Over the period studied, the proportion of patients who died within 30 days of surgery fell by 16% from 7.7% to 6.5%; the proportion of patients with serious complications fell by 3% from 14.8% to 14.4%; and the proportion of people who died because of failure to rescue fell by 11% from 22.9% to 20.3%.
  • When hospitals were split into five groups depending on their level of improvement over the period, the best performing fifth of hospitals reduced mortality by 37% from 9.0% to 5.7%; reduced serious complications by 11% from 15.2% to 13.5%; and reduced failure to rescue by 25% from 25.2% to 18.9%.
  • The worst performing fifth of hospitals increased mortality by 12% from 6.9% to 7.7%; increased serious complications by 5% from 14.6% to 15.4%; and increased failure to rescue by 4% from 21.5% to 22.3%.
  • Overall, 64% of the variation in mortality over time was explained by rates of failure to rescue. Rates of serious complications explained 4–7% of the variation in mortality. About 30% of the variation in mortality was unexplained and may be due to factors not measured in this study.

What does current guidance say on this issue?

NICE’s 2007 guideline on recognising and responding to deterioration in acutely ill adults will be amended to note that the NEWS2 early warning score has been endorsed by NHS England and the Royal College of Physicians.

NEWS2 assesses respiration rate, oxygen saturation, systolic blood pressure, pulse rate, level of consciousness or new confusion, and temperature. Each measure is scored and combined to give an overall assessment of how ill a patient is.

Higher scores trigger increasingly urgent clinical responses and increased frequency of monitoring. NEWS2 should now be in use by all hospitals in England since the end of March 2019.

What are the implications?

This study supports current recommendations to monitor patients for signs of deterioration in their clinical condition and to respond adequately, as reducing failure to rescue was the main driver for the improved mortality.

The study did not explain how the improvements were made and did not mention any national US early warning systems. This differs from the UK where NEWS2 is becoming the standardised process, which should improve communication and response. Adopting the same system across hospitals will also be beneficial considering staff movement, high usage of locums and bank staff.

Citation and Funding

Fry BT, Smith ME, Thumma JR et al. Ten-year trends in surgical mortality, complications, and failure to rescue in Medicare beneficiaries. Ann Surg. 2019; Jan 23. doi: 10.1097/sla.0000000000003193 [Epub ahead of print].

No funding information was provided for this study.



Ghaferi AA, Birkmeyer JD, Dimick JB. Variation in hospital mortality associated with inpatient surgery. N Engl J Med. 2009;361(14):1368-75.

McGaughey J, O'Halloran P, Porter S, Blackwood B. Early warning systems and rapid response to the deteriorating patient in hospital: a systematic realist review. J Adv Nurs. 2017;73(12):2877-91.

NICE. Acutely ill adults in hospital: recognising and responding to deterioration. CG50. London: National Institute for Health and Care Excellence; 2007.

RCP. National Early Warning Score (NEWS) 2. Standardising the assessment of acute-illness severity in the NHS. London: Royal College of Physicians; 2017.


Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre


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