El muestreo: los Expertos

The process of care for EGS patients is highly variable depending on the severity of the illness and the disease process responsible. Intra-operative processes such as the use of the World Health Organisation’s Safe Surgery Saves Lives checklist (Weiser et al., 2010) will not be covered in detail in this review because these processes have been studied in much more depth than the peri-operative care that is the focus of this thesis and are often identical to those of high-risk elective surgery. Peri- operative processes for EGS patients include the initial work-up, admission, investigations and diagnosis, followed by the initiation of any non-surgical treatment and pre-operative assessment and optimisation. On-going post-operative care and the teamwork and coordination that are common to all phases of care for EGS patients will also be examined. An extensive review of every individual process of care would be a thesis in its own right and therefore this section of the review will only describe processes that are applicable to the majority of EGS patients and for which there is a significant evidence base.

Efforts to measure the reliability with which these processes are performed will also be examined. The concept of reliability has been adapted for use in medicine from industry, in particular from systems engineers designing complex industrial applications in which process failures must be minimised. Reliability in healthcare has been defined by the Institute for Healthcare Improvement (IHI) as “failure-free operation over time” (Resar, 2006) and this is an aspect of quality in which healthcare is a long way behind. The majority of healthcare processes run at between 50% and 90%

49 reliability, a level unthinkable in industry where failure in processes typically occur on 0.001% of occasions. Of course many industrial processes are identical time after time, whereas every patient is different. Nonetheless process reliability in healthcare, where it is measured, is often poor.

Remarkably few EGS processes have robust empirical evidence specific to this group of patients. The best researched field is that of the treatment of sepsis and the key processes are defined in the surviving sepsis guidelines (Dellinger et al., 2008). These include immediate resuscitation of septic patients, appropriate investigations to identify the source, early intravenous antibiotics and control of the source of infection as soon as possible after resuscitation (Dellinger et al., 2008). A recent meta-analysis of studies examining the use of the surviving sepsis guidelines has demonstrated an odds ratio for survival of 1.7 in favour of the guidelines (Chamberlain et al., 2011). The processes that make up the surviving sepsis care bundle form a major part of the RCS guidelines for the care of high risk surgical patients (Royal College of Surgeons of England, 2011b). Unfortunately there is little evidence as to the reliability with which these evidence-based guidelines are applied in the NHS.

Thromboprophylaxis against deep vein thrombosis (DVT) or pulmonary embolism is another process that has been widely researched. Evidence for the efficacy of thromboprophylaxis in elective surgical patients is robust but the evidence in EGS is far less developed. The only randomised controlled trial of prophylaxis in EGS patients was discontinued early but demonstrated a non-significant reduction in DVTs of 65% (Bergqvist et al., 1996). The current National Institute for Health and Clinical

Excellence (NICE) guidelines recommend that all acute surgical patients with an inflammatory or intra-abdominal condition should be considered at high risk of thrombosis; this includes essentially all EGS patients. These patients should have mechanical prophylaxis with compression stockings or intermittent pneumatic compression started on admission with the addition of pharmacological thromboprophylaxis for patients without risk factors for bleeding (National Institute for Health and Clinical Excellence, 2010). Two studies, both at single centres, have documented the adherence to these guidelines and this varies markedly between sites (Table 3.2) (McCulloch et al., 2010,

50 Stevenson et al., 2007). It is this kind of variability in care delivery that may explain some of the differences in outcomes between providers.

Physiological signs play a crucial role in diagnosis and evaluation of EGS patients. The “vital signs” of pulse, blood pressure, temperature, respiratory rate and oxygen saturation allow clinicians to assess the severity of disease and the patient’s response to it. Early warning scores have attempted to amalgamate these signs into a single score that predicts patients at risk of deterioration or in need of intensive care admission. The most frequently used algorithm is the Modified Early Warning Score (MEWS), which was developed in medical patients (Subbe et al., 2001) and has been validated for surgical inpatients (Gardner-Thorpe et al., 2006). It is not clear whether the use of early warning scores improves patient outcomes in EGS but both NICE and NCEPOD have recommended their universal use (Findlay et al., 2011, National Institute for Health and Clinical Excellence, 2007). Both NCEPOD and one independent single centre study (McCulloch et al., 2010) have examined the adherence to these policies and found similar reliability of about 70%.

Reliability of a number of other processes has been investigated in studies examining multiple processes of care for EGS patients (Table 3.2). Unfortunately the majority of reliability research is conducted under the guise of local audit and therefore not published. Work that does make it into the literature tends to be from single sites and only assesses the reliability of single processes. This makes it difficult to get a good idea of the actual variability in practice between EGS units.

Stevenson et al. have demonstrated that it is possible to improve adherence to selected processes of care using a brief questionnaire and generalised feedback (Stevenson et al., 2007). Reliability can be improved even further by issuing detailed job descriptions to surgical staff to clarify their roles and responsibilities. The longevity of the improvements following such an intervention is unknown. An alternative approach to improving processes of care in EGS is the use of quality improvement techniques derived from industry (Nicolay et al., 2012). McCulloch et al. have demonstrated improvements in process reliability using a “lean” intervention, which consists of process mapping, simplification and streamlining of processes, increasing failure visibility and completing Plan-Do-

51 Study-Act (PDSA) cycles of improvement (McCulloch et al., 2010). In this study lean was associated with significant improvements in process completion that persisted for 10 months after the project was complete. Two processes that were not subject to the lean intervention did not improve in the same time-period but there were no formal control sites in this study.