Patients presenting for urological surgery range from the young and fit to the elderly with multiple, often significant, coexisting diseases. This latter group poses a significant challenge in the perioperative period, sometimes irrespective of the type of surgery. Among our patient population lies a hidden subgroup of high-risk individuals, who experience a stark disparity in outcomes. These patients account for 80% of in-hospital deaths after a surgical procedure and represent approximately 10% of our inpatient surgical workload.
The first crucial step is to accurately identify those “at risk.” Previous reports have highlighted this as a shortfall.
Traditionally, anesthesiologists have used simple risk indices such as the American Society of Anesthesiologists (ASA) score (grades I-V based on the anesthesiologist’s subjective assessment of comorbidity severity). This may be supplemented by evaluating preoperative functional capacity, widely viewed as a key element of perioperative risk assessment. Historically, this involved determining a patient’s Metabolic Equivalent of Task (MET), where 4 METs equate to the ability to walk up one flight of stairs (1 MET = amount of oxygen consumed at rest = 3.5 ml kg-1 min-1). More objective measurement of functional capacity, now commonplace in most UK hospitals, is achieved by cardiopulmonary exercise testing (CPET). CPET quantifies an individual’s functional ability to respond to the increased metabolic demand of surgery by evaluating cardiovascular, respiratory, and circulatory systems. However, CPET is time-consuming, and interpreting the complex measures derived requires specific expertise.
Ideally, risk assessment begins at the earliest opportunity, in the outpatient clinic, when surgical intervention is initially considered. It can be carried out by the surgeon, junior doctor, or allied health professional. Nowadays, smartphones are ubiquitous, and numerous well-validated online risk calculators make determining an individual’s risk quick and easy, allowing us to better inform our patients.
Risk calculators include “general” and “specialty-specific” models. While there are no specific urological risk calculators, several general tools can be applied. One of the most widely validated scoring systems is the Portsmouth Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (P-POSSUM). This tool incorporates 18 variables (12 physiological and 6 operative) to predict morbidity and mortality. A key differentiator from other scoring systems is its use of variable weighting, where factors with the strongest association to a poor outcome “count” for more. Another key advantage of P-POSSUM is that it accounts for intraoperative events (when applied preoperatively, these parameters can be estimated). Specialty-specific variants include CR (colorectal)-POSSUM, O (esophagogastric)-POSSUM, and Vascular-POSSUM. P-POSSUM can be accessed at: http://www.riskprediction.org.uk/index-pp.php
Another useful and more current example is the Surgical Outcome Risk Tool (SORT). Developed in response to the 2011 NCEPOD study on perioperative care, data from the 16,788 patients included in the study were used to develop and validate the tool. Unlike P-POSSUM, SORT allows filtering by specialty (“Urinary system and male reproductive organs”), sub-group (Kidney/renal pelvic, Ureter, Bladder, Urethra, Prostate, Genitalia), and even individual procedure. Ultimately, SORT provides an estimate of the risk of death within 30 days of an operation. SORT is available as a free app (App Store – Apple; Google Play – Android) or can be accessed at: http://www.sortsurgery.com/
In the US, the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) has developed a robust risk calculator based on >2.7 million operations from 586 hospitals (2011-14). The tool uses 20 patient predictors and the planned procedure to estimate the chance of an “unfavorable outcome” (complication or death) after surgery. A similar multidisciplinary initiative is underway in the UK: the Perioperative Quality Improvement Programme (PQIP). The ACS NSQIP Surgical Risk Calculator can be accessed at: http://riskcalculator.facs.org/RiskCalculator/index.jsp
Although the above risk calculators are well-validated, they provide estimates only. Nevertheless, they can be valuable adjuncts in perioperative risk assessment, helping us to better inform patients facing a surgical procedure. Give them a try!
Author: Dr. Tim Warrener, ST5 Anaesthetics and SWARM Research Fellow, Plymouth Hospitals NHS Trust.
Edited by: Mr Ivo Dukic, Consultant Urological Surgeon, Unversity Hospitals Birmingham NHS Foundation Trust, subspecialising in endourology and kidney stone surgery, Birmingham, United Kingdom. Further information can be found through his Top Doctors profile or book an appointment through the Harborne Hospital, HCA Healthcare or the Priory Hospital, Edgbaston, Circle Health Group. Website: ivodukic.co.uk. Twitter (X) @urolsurg
References
- Findlay GP, Goodwin APL, Protopapa KL, Smith NCE, Mason M. Knowing the risk: a Review of the Peri-Operative Care of Surgical Patients. National Confidential Enquiry into Patient Outcome and Death; London, 2011. Retrieved on 18th May 2017 from url: http://www.ncepod.org.uk/2011report2/downloads/POC_summary.pdf
- The Royal College of Surgeons of England/Department of Health. The higher risk general surgical patient: towards improved care for a forgotten group. Retrieved on 18th May from url: https://www.rcseng.ac.uk/library-and-publications/college-publications/docs/the-higher-risk-general-surgical-patient/
- Protopapa KL, Simpson JC, Smith NCE, Moonesinghe SR. Development and validation of the Surgical Outcome Risk Tool (SORT). Br J Surg 2014. 101: 1774-1783.
- Perioperative Quality Improvement Programme (PQIP). NIAA-HSRC. Retrieved on 7th June from url: https://pqip.org.uk/Content/home