Ambulatory Urology and Urogynaecology. Группа авторов
telephone or computer. It should happen far enough in advance so that patients' co‐morbidities, medications, and social factors can be optimised preoperatively.
The pre‐operative assessment begins with gathering information about health, medications, and social circumstance. The health assessment is generally history‐based and most commonly involves a questionnaire with basic screening questions and more detailed history where appropriate. Pre‐operative examination and investigations including blood tests, ECG, and X‐rays are less useful in most patients. A decision is then made regarding whether the patient is suitable for day surgery. Modern ambulatory units have moved away from a specific set of contraindications and instead assess patient suitability individually according to the combination of physiological status, social circumstance and intended procedure.
Social Selection Criteria
Several social factors must be considered before ambulatory surgery. Patients or carers must be able to understand the nature of the procedure, and be willing to adhere to the peri‐operative instructions. Patients must have appropriate support at home; in general, they need to be discharged into the care of a responsible adult for 24 hours after the operation, although this is probably excessive for some minor operations. Additionally, a generally accepted rule is that they must live within one hour's travel time to the surgical unit. In those living remote from ambulatory unit, the option of an overnight local lodging can be discussed, instead of overnight hospital admission.
Physical Selection Criteria
There are multiple factors that reduce the suitability of patients for day surgery and must be assessed in detail prior to surgery (Fong 2014). Identifying high‐risk patients can help facilitate a multidisciplinary strategy to optimise their pre‐operative condition, anticipate intraoperative challenges, and plan postoperative disposition (Walsh 2018). Although a comprehensive review of these is beyond the scope of this chapter, we will mention a few notable parameters.
Age should not independently decide whether a patient is suitable. In one study, elderly patients did not have worse outcomes than younger patients (Chung 1999), although in another, advanced age was associated with greater rates of readmission (Whippey 2013). Ambulatory surgery may actually confer some benefits to the elderly population, having been shown to reduce rates of post‐operative cognitive dysfunction (Rasmussen 2015).
The American Society of Anaesthesiologists grading system (ASA grade) is used to evaluate a patient's physical state before surgery and classifies patients into 6 categories. Grade 1 being a normal healthy patient and grade 5 being moribund patient. The ASA grade is not a particularly useful measure of suitability for day surgery. An ASA 3 patient does not experience greater complication rates when compared to an ASA 1 or 2 in the medium to late post‐operative period (Ansell 2004). Some ASA 4 patients may also be suitable for procedures undertaken using local or regional anaesthesia.
Suitability of obese patients is a controversial area, a body mass index (BMI) of up to 40 being acceptable for the majority of procedures and many anaesthetists would accept higher BMIs (Atkins 2002). Complication rates do appear to be higher in the extremely obese group (BMI > 50 kg/m2), although readmission rates are not significantly greater (Joshi 2013).
With regards to chronic medical conditions, a general rule is that stable patients are fit for ambulatory surgery. Chronic obstructive pulmonary disease (COPD) is not a contraindication for ambulatory surgery. Asymptomatic patients have a low risk of post‐operative complications, but those who have been symptomatic within a month of the proposed surgery may need to have their procedure postponed (Warner 1996). Smokers should be encouraged to stop smoking, as even short‐term cessation pre‐operatively has been demonstrated to reduce complications (Myles 2002). Patients with obstructive sleep apnoea should have good control of symptoms and be established on nasal continuous positive airway pressure pre‐operatively and during the post‐operative period.
Cardiovascular status should also be assessed pre‐operatively. Patients with hypertension should have their blood pressure reasonably controlled. The majority of those with ischaemic heart disease will be suitable, except for those with unstable or severe angina and those who have experienced recent myocardial infarction. Additionally, ambulatory surgery is generally not undertaken within a year of drug‐eluting stent placement (Wijeysundera 2012). Diabetes mellitus does not itself preclude a patient from day surgery; in fact, day surgery reduces disruption to normal routine. However, patients should ideally be screened for other co‐morbidities including cardiovascular and renal dysfunction. Patients with end‐stage renal failure may be appropriate for minor ambulatory procedures undertaken under local or regional anaesthesia but, given their poor physiological state and the practical issues with regards to dialysis, major ambulatory operations are generally contraindicated.
Preparation for Surgery
Once the patient has been adequately assessed and deemed suitable for ambulatory surgery, the clinical team will start to prepare. This will involve completion of any further anaesthetic investigations and surgical diagnostics. Consent should be obtained with explanation and post‐operative plan discussed.
The patient must be given appropriate information regarding the perioperative period. This will include an overview of fasting requirements, medications that need to be taken, and information pertaining to personal hygiene. In addition, simple information about location and timings should be provided. Finally, the patient and carer/responsible adult should be given information on whom to contact for queries or help with post‐operative complications.
Anaesthesia
Pre‐operatively, a full anaesthetic assessment should be performed, including previous anaesthetic history, post‐operative nausea and vomiting (PONV) risk, and an airway assessment. PONV a common complication of anaesthesia, occurs most often in females, those with a similar past history, those with motion sickness, nonsmokers, and those requiring post‐operative opioids (Apfel 1999). Pre‐operative assessment should aim to identify risk factors for difficult pain control allowing for individualised perioperative analgesia planning.
Most current anaesthetic agents convey predictable and rapid recovery. Desflurane‐based anaesthetic has been reported to have the most predictable emergence from anaesthesia (Dexter 2011; Watchel 2011), although desflurane and sevoflurane‐based anaesthesia appear to provide equal numbers of patients eligible for fast‐tracking (White 2009). Propofol is frequently used for induction and maintenance of ambulatory anaesthesia, due to rapid metabolism and emergence, few side‐effects, and low rates of PONV.
Depth of anaesthesia monitors, such as Bi‐spectral Index (BIS), facilitate drug titration and have been shown to reduce drug consumption, reduce PONV (Liu 2004), and reduce rates of post‐operative cognitive dysfunction in elderly patients (Chan 2013).
Post‐operative pain will vary according to patient factors as well as the specifics of the surgical procedure and anaesthesia used. Utilising minimally invasive surgical techniques and regional anaesthesia are obvious ways to reduce pain. Regional anaesthetic techniques such as peripheral nerve blockade or neuraxial blockade, can mitigate the side effects of general anaesthesia such as PONV and aspiration pneumonia and may accelerate recovery by facilitating early analgesia (Moore 2013) and reducing opioid requirement. For neuraxial blocks, drug selection and dosing must be carefully considered so that prolonged effects do not delay discharge.
A number of antiemetics have been investigated and compared for efficacy. The 5HT3 antagonists such as ondansetron have good efficacy, especially when used in combination with dexamethasone. These should be started before the end of anaesthesia (Tang 1998) and continued in the community if necessary. Side effects should be evaluated when choosing an agent. Dexamethasone should be avoided in patients with lymphoma because of risk of tumour lysis syndrome. Ondansetron should be avoided in patients with, or at risk of long QT.
Early Recovery: Emergence from Anaesthesia