Description of the condition

Estimates suggest that 234 million surgical operations take place each year globally, including 8.1 million in the UK, 8.3 million in France and 7.7 million in Germany (Weiser 2008). An estimated 2.9 million patients receive a general anaesthetic in the UK each year (Woodall 2011). Safety and avoidance of unnecessary risk are paramount, and effective preoperative assessment is an integral part of patient care.

The care and assessment of patients during the time leading up to a surgical procedure are divided into several stages. The initial decision that an operation is required is usually made by the surgeon and the patient. Next, information about the patient’s health is collected with the goals of (1) determining whether the patient is well enough to undergo the planned procedure and receive any necessary anaesthetic and (2) planning the patient's care. This stage is followed by the final decision, made by the surgeon, the anaesthetist and the patient, immediately before the procedure regarding whether to proceed with the operation and the anaesthetic. The middle phase of investigation and planning of management, here termed preoperative assessment (POA), is the topic of this review, rather than the initial or final decision on whether to carry out the planned anaesthetic and operation.

The primary aim of POA is optimization of the patient's pathway through surgery, including preparation before surgery and recovery afterwards. This involves assessing the patient’s state of health and determining whether he or she is likely to suffer complications or adverse effects when given general anaesthesia. Co‐morbidities or illnesses that are identified may then be treated and optimized before surgery. POA serves many other important functions such as providing education and information (which may reduce patient anxiety and facilitate informed decisions about care), obtaining consent and planning for postoperative care, recovery and discharge. Postoperative planning is particularly important if a patient for whom the operation is considered necessary is assessed as being at higher risk.

POA is essential to enable patients to give fully informed consent and to share in decision making about their treatment. Inadequate POA, or assessment that takes place close to the scheduled surgery, can lead to last minute cancellation of operations because the anaesthetist or the surgeon is not prepared to go ahead as planned, or because going ahead without identifying potential risks could jeopardize patient safety. Patients may cancel their operation, sometimes at short notice, if they are uncertain or have unanswered questions or concerns. Patient cancellation or non‐attendance has been shown to account for 18% to 23% of surgery cancellations (Gonzalez‐Arevalo 2009; Schofield 2005). Timely and complete POA may prevent such cancellations.

Description of the intervention

Historically POA was designed largely for inpatient surgery and was centred on the clinical team that was planning to carry out the surgery. Patients were admitted to the hospital a day or so before surgery and were assessed on the ward by surgeons or their trainees or residents, with the anaesthetist visiting the evening before surgery. Alternative models are now used in many parts of the world. The costs of unnecessary hospital stays before surgery are not acceptable to many funders. The increasing role of day‐case (ambulatory) surgery or same‐day admission surgery has required that POA be separated from the hospital admission for surgery. POA now is often an outpatient service performed in dedicated clinics run by a multidisciplinary team, often under the supervision of anaesthetists. This assessment may take place before or on the same day as surgery.

These changes in service delivery have also been driven by changes to medical and nursing training and, in some countries, by legislation on working hours. The reduction in junior doctors' hours in the European Union, together with moves to enhance medical postgraduate education and reduce hours spent 'clerking' (Department of Health 2004; MacDonald 2004), has meant that in these countries, specialized nurses are successfully undertaking many of the roles that traditionally were performed by doctors. These enhanced practice roles include the care of diabetic and cardiac patients. Published and ongoing Cochrane reviews have considered nurses taking on new roles in primary care, in the care of HIV and respiratory patients (French 2003; Kredo 2012; Kuethe 2011; Laurant 2004) and in delivery of anaesthetic services (Lewis 2013). Nurse‐led POA clinics operate with supervision and training provided by specialist medical staff, often anaesthetists. Agreed protocols or computer‐based decision analysis tools are often followed (Barnes 2000). Nurses are responsible for history taking, physical examination, ordering of tests and interpretation of test results. They may then seek further medical advice or consultation as needed for any abnormalities detected or may approve the patient as fit for surgery.

How the intervention might work

Expansion of the nursing role in this way has implications for both health services and patients. More appropriate use of medical and nursing time and enhanced training might deliver improved planning of the patient pathway, reduce last minute cancellations due to unresolved or undetected clinical issues and increase patients' knowledge and understanding, so they can make informed decisions about whether to proceed with the planned surgery. Evaluation of POA programmes has considered a range of outcomes such as cancellations, accuracy of assessment and patient knowledge and satisfaction.

The implementation of clinics for POA has been described in many observational and some intervention studies. Outcomes reported include accuracy of screening (Vaghadia 1999), completeness of history (Reed 1997), investigations ordered (Koay 1996; Reed 1997), costs (Pollard 1996), consultation time, participant satisfaction (Reed 1997; Schiff 2010; Walsgrove 2004), gain in participant knowledge or information (Schiff 2008) and the proportion of operations cancelled (Koay 1996; Pollard 1996; Pollard 1999; Rai 2003; Reed 1997). Some studies are purely descriptive (Koay 1996); others compare results with those of other models of preoperative assessment. The  intervention considered may be clinic versus ward location with staffing unchanged (Pollard 1996) or a change in the timing of assessment (Pollard 1999). In several studies, two interventions are simultaneously assessed: nurse‐led versus doctor‐led assessment and clinic versus ward location (Rai 2003; Reed 1997).

The literature specifically comparing nurse‐led POA with doctor‐led POA in the same setting is smaller. Three observational studies have compared preoperative risk assessment by nurses with anaesthetist opinion in cross‐sectional or cohort studies (Vaghadia 1999; van Klei 2004; Whiteley 1997). The accuracy of preoperative risk assessment can be considered a diagnostic accuracy question, with anaesthetist opinion taken as the reference standard. Reported sensitivity, that is the proportion of participants for whom the anaesthetist considered that additional work‐up was required who were accurately detected by nurses, varied from 83% (van Klei 2004) to 47% (Vaghadia 1999). The specificity was high in both studies, at 87% and 86%, respectively. The performance of nurses has been compared with that of interns in a POA clinic, both cross‐sectionally (Whiteley 1997) and by using an historic cohort design (Jones 2000). Results for process outcomes are inconsistent, with nurses performing better than doctors on some outcomes, such as history taking (Reed 1997; Whiteley 1997), but not on others, such as appropriateness of the investigations ordered (Jones 2000).

Cross‐sectional studies provide valid evidence for diagnostic test accuracy questions, but evaluation of the consequences of any errors in preoperative assessment, such as cancellation on the day of surgery and delays or complications, requires longitudinal studies. Observational designs such as cohort studies are prone to both selection bias, with lower‐risk participants possibly selected for nurse‐led assessment, and performance bias if the care process differs in other ways between intervention and comparison groups. Randomized controlled trials provide the highest quality evidence.

Why it is important to do this review

Changes to medical staffing and training and the need to increase organizational efficiency in the operating theatre have led to changes in the staffing of POA, including an enhanced role for nurses. Nurse‐led POA is now widespread internationally and is an accepted part of practice; it offers many potential benefits for patients. It is important to demonstrate that standards of patient care are maintained as nurses take on these responsibilities, but the evidence base for the impact of nurse‐led POA on patient care has not been systematically assessed. Existing observational evidence is sparse and has focused on process measures and diagnostic accuracy. We examined available randomized studies to assess whether the quality and outcomes of preoperative assessment led by nurses are equivalent to those of preoperative assessment led by doctors. We did not study measures of accuracy of preoperative assessment as outcomes in this review, as these diagnostic accuracy questions can be assessed through a variety of study designs; including only results from randomized controlled trials will lead to an incomplete synthesis of evidence on this issue. We therefore focused on consequences such as cancellation of surgery, complications and patient reported outcomes.