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Current Anaesthesia & Critical Care (2007) 18, 181–187

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FOCUS ON: DAY CASE

Day surgery for all: Updated selection criteria

Ian Smith�

Directorate of Anaesthesia, University Hospital of North Staffordshire, Newcastle Road,Stoke-on-Trent, Staffordshire ST4 6QG, UK

KEYWORDSPreoperativeassessment;Selection criteria;Perioperativecomplications

ee front matter & 2007acc.2007.07.003

82 553054; fax: +44 178ess: damsmith@btinter

Summary Increasing experience has led to a considerable broadening of theselection criteria for day surgery. It is important to consider the impact of theplanned procedure on the patient as a whole and not to rely on a series of somewhatarbitrary cut-offs.

Day surgery is now seen as the treatment of choice for a wide range of operativeprocedures. It is no longer acceptable to choose only the fittest patients with theintention of minimising all peri-operative complications. Instead, day surgery shouldbe seen as the default option, with inpatient care considered only if it will addsignificant benefit to the patient’s treatment. This will usually be in situations wheredelayed complications are likely or where the patient’s safety would becompromised by early discharge.

Preoperative assessment is important, not to eliminate all risk, but to ensure thatall co-morbidities are known, their treatment is optimised and the patient is wellinformed and adequately prepared for their surgery. For the more challenging daycase patients, it can also ensure that the most appropriately skilled surgeons andanaesthetists are available on the chosen day of surgery.& 2007 Elsevier Ltd. All rights reserved.

Introduction

Where once day surgery was seen as a specialist andhighly selective form of care, suitable for only thesimplest of procedures and the fittest of patients; ithas now become the treatment of choice for a widerange of cases. This change has come about throughthe experience of enthusiasts who have challengedexisting limits and discovered that the benefits ofday surgery may still be achieved in the presence ofnumerous coexisting conditions.

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Selection criteria: surgical

The Audit Commission publishes a basket of 25surgical procedures1 which is useful for compara-tive, benchmarking purposes, but was never in-tended to be a comprehensive list of operationswhich can and should be performed as day surgery.The British Association of Day Surgery’s Directory ofprocedures2 suggests achievable rates of daysurgery for a much larger list of 160 operations,but even this is not exhaustive. The major factorswhich determine whether or not a given operationcan be performed on a day case basis are thedegree of tissue damage, and hence pain, the

ed.

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extent of blood and fluid loss and the extent ofpostoperative care and complications. Althougharbitrary time limits have been suggested in thepast, modern anaesthesia allows acceptably rapidrecovery after procedures lasting several hours.Minimally invasive surgery allows these longer andmore complex procedures to be completed withrelatively little trauma or blood loss and results inlevels of postoperative pain which are generallycontrollable with oral analgesia, supplementedwith local anaesthesia. Operative time should nolonger be a limit for day surgery.

After surgery is completed, there should be nocontinuing blood loss or requirement for fluidtherapy and no need for complex postoperativecare which is difficult to provide in the community.Postoperative complications should be uncommon,although their timing must also be considered.Some surgeons prefer an overnight stay followingtonsillectomy or laparoscopic cholecystectomy be-cause of concerns about bleeding or bile leaks.However, bleeding either occurs within a few hours,before day cases would be discharged, or is delayedfor several days, when even the most conservativelymanaged patients would be at home. Similarly, bileduct damage is either immediately obvious or doesnot present for several days.

These principles can be applied to numerousother surgical procedures, which can then beperformed as day surgery if circumstances permit.Surgeons may legitimately decide that a particularoperation will be too complex or extensive in anindividual patient to permit day surgery, butdecisions on medical and social suitability are bestmade at a specialist pre-assessment clinic,3 result-ing in a default to day surgery approach for manyprocedures.

Selection criteria: social

Although patients will not be discharged from theday unit until they are stable, their recovery is farfrom complete. In particular, fine judgement andprecise motor control may take several hours torecover. Therefore, patients who have receivedgeneral anaesthesia or sedation must be accom-panied by a responsible, physically able adult whocan shield them from dangerous activities, at leastuntil the following day. The escort will also beavailable to summon help in the (extremely rare)event of a major complication. A telephone mustbe readily available for such an eventuality.

While the residual sedative effects of modernanaesthetics are virtually undetectable within 24 h,some surgical procedures may limit activities for a

much longer period. For example, upper limbprocedures may interfere with everyday tasks,including dressing and cooking, while lower limbsurgery may significantly impair mobility. Thediscomfort following inguinal hernia repair maypreclude safe driving for several days.

Social factors are an increasingly common reasonfor excluding patients from day surgery. Singlepatients and those with elderly partners may nothave suitable carers, while those with multiplesmall children are likely to require additional help.With adequate planning, many of these patientswill be able to make arrangements with family,friends or neighbours. Sometimes, this will involvestaying away from their usual home for a few days.There is no firm evidence to preclude long journeysimmediately after day surgery, but these should notbe undertaken lightly. Since it will not be possibleto rapidly return to the hospital, facilities foremergency care must be available at the finaldestination. Discomfort and nausea may makeprolonged travel unpleasant, but some patientsare willing to accept these disadvantages to avoidhospital admission. There is also no good evidenceon the risks of air travel after day surgery. Majorsurgery undoubtedly increases the risks of throm-boembolic events, but some airlines forbid flyingfor some time after any surgery.

Selection criteria: medical

Day surgery patients have previously been selectedaccording to very strict medical criteria in anattempt to avoid almost all peri-operative compli-cations. Not only is this strategy relatively ineffec-tive, but it also gives no consideration to the timingof these complications. Problems which will occurduring the procedure, or in the first few hours ofrecovery, should be able to be managed just as theywould be for inpatients. Provided these problemshave been resolved, and are not expected to recur,there is no indication for an overnight hospital stay.Only complications which are likely to affectpatients after they are discharged, or which arebetter managed in hospital, should prevent daysurgery. As this important distinction concerningperi-operative complications has become clearer,and with increasing experience and evidence fromday surgery in less healthy patients, broaderguidelines for patient selection have been devel-oped.4,5 However, knowledge of these revisedguidelines appears limited,3 with outdated criteriastill being commonly applied.

Selection of patients should be based on theiroverall physiological status and not governed by

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arbitrary limits such as age, weight or ASA status.For any pre-existing condition the patient mayhave, its nature, stability and functional limitationshould all be evaluated. The condition(s) should beunder control and any medical treatment must beoptimised; otherwise the patient is not yet suitablefor any form of elective surgery. It is thenimportant to ask whether the patient’s manage-ment or outcome would be improved by pre- orpostoperative hospitalisation. Unless this would bethe case, surgery should take place on a day casebasis.

Age

Both medical and social problems tend to increasewith age, but these should be considered indepen-dently, without any arbitrary upper age limit.4,5 Asmight be predicted, there is an associationbetween increasing age and the development ofsignificant changes in intra-operative haemody-namics, but this is another example of a peri-operative complication which does not result in anadverse outcome after day surgery.6 Pain manage-ment after operations such as hernia repair is ofteneasier in older patients, perhaps because they haveless muscle mass and are less active than theiryounger counterparts. Elderly patients also benefitfrom day surgery through a significant reduction inpostoperative cognitive dysfunction.7

ASA status

While the American Society of Anesthesiologists(ASA) classification is a simple index of chronichealth, it is far too crude and non-specific toreliably select day surgery patients. Patients of ASA3 experience no more complications than those ofASA grades 1 and 2 in the medium-to-late recoveryperiod8 and do not encounter more problems, orplace a greater burden on primary care, after daysurgery.9 While specific conditions should always beassessed on an individual basis, in general, patientsof ASA 1–3 should be suitable for day surgery unlessthere are other contraindications. Even some ASA 4patients will be acceptable, provided their surgeryproduces minimal postoperative disturbance, aswill often be the case when performed under localanaesthesia.

Obesity

Obesity poses numerous challenges, including diffi-culties with venous and airway access, mechanicalproblems with breathing, positioning and surgical

access and an increase in cardiovascular andrespiratory complications. However, the majorityof these occur during the peri-operative and earlyrecovery periods and would be just as likely to arisewith inpatient care. For patients with moderateobesity, following an hour or two of recovery, all ofthese issues will have resolved with a low likelihoodof further complications preventable by overnighthospital admission. The use of short-acting drugsand avoidance of opioid analgesia, both commonfeatures of day surgery, have obvious benefits forobese patients. Several observational studies con-firm no increase in unplanned admissions followingday surgery in obese patients.10

Current British guidelines suggest patients with abody mass index (BMI)p35 kgm�2 should be accep-table for day surgery, providing there are no othercontraindications, while those of BMI 35–40 kgm�2

should be acceptable for most procedures.5 Eventhese limits may be a little conservative. Peri-operative complications become much more com-mon above a BMI of 40 kgm�2, although these stilltend to resolve within a few hours with no dramaticincrease in the need for hospital admission.11

Currently, 91% of Canadian anaesthetists wouldaccept patients of BMI 35–44 kgm�2 for day surgeryand half would accept patients over 45 kgm�2,provided they were otherwise healthy.12 Certainlyit is important not to look at BMI in isolation.Consideration must also be given to the site andnature of surgery (especially whether it is likely tocompromise respiratory function), while poor over-all fitness and smoking both increase the risksassociated with any given level of obesity.11

Hypertension, congestive cardiac failure and sleepapnoea are also all common in morbid obesity anddramatically reduce the acceptability of thesepatients for day surgery.12

Cardiovascular diseases

HypertensionWhile hypertension is a long-term health risk whichbenefits from treatment, its association withincreased peri-operative risk has probably beenoverstated. Although hypertension does increasethe incidence of peri-operative cardiovascularcomplications,13 the increased risk is relativelysmall in magnitude and evidence of pre-existingend-organ damage is probably a greater risk factor.

Patients presenting for day surgery often haveelevated blood pressures. However, a reliablediagnosis of hypertension requires high bloodpressure to be recorded on more than one occasion.It is therefore difficult to justify cancellation of

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patients on the basis of raised blood pressuredetected for the first time on the day of surgery,although this should be avoidable with timely pre-assessment. When hypertension is suspected in thepre-assessment clinic, and if surgery is not urgent,there is time to refer the patient for furtherassessment. Issuing home blood pressure monitorsfrom the pre-assessment clinic is a simple and rapidway to screen out patients with ‘‘white coat’’hypertension who do not require further treat-ment.14 If hypertension is diagnosed, treatmentshould be started to reduce long-term risk and thisshould be continued during the peri-operativeperiod.

For more urgent surgery, the likelihood ofmyocardial ischaemia and significant cardiovascularrisk is most likely when the systolic blood pressureexceeds 180mmHg and/or the diastolic pressure is110mmHg or more (i.e., stage 3 hypertension) andelective surgery should probably be deferred in thisgroup.13 These are little evidence to support thisrecommendation, however, and no evidence thatdeferring surgery reduces peri-operative risk inpatients with lower arterial pressures. Rapidmeasures to control high blood pressure, such assublingual nifedipine and sedation, do not reducecardiovascular risk, may increase morbidity andshould be avoided.13

For patients with existing hypertension, controlshould be optimised with medication continuedthroughout the peri-operative period. It is oftensuggested that angiotensin converting enzyme(ACE) inhibitors (e.g., ramipril, enalapril) shouldbe withheld before surgery because they areassociated with severe peri-operative hypotension.This practice is controversial, however, as thedegree of hypotension is generally mild and easilycorrectable with simple measures15 and ACE in-hibitors also convey benefits, including attenuatedsympathetic responses, cardioprotection and im-proved renal function.16 Continuing ACE inhibitorsalso simplifies patient instructions.

Ischaemic heart diseaseWhile angina at rest or on minimal effort is acontraindication to day surgery, patients withstable angina are acceptable, provided this isoptimally controlled and there are no other majorrisk factors. It is imperative that established b-blockade is continued through the peri-operativeperiod.17 Previous myocardial infarction is not acontraindication for day surgery, provided this hasnot been within the past 6 months when the risk ofre-infarction is though to be higher.5 With improvedmanagement of myocardial infarction, it has beensuggested that an interval of only 6 weeks is

necessary for urgent elective surgery, since this issufficient time for the atherosclerotic plaque tohave stabilised.18 Similar intervals are recom-mended following cardiac revascularisation proce-dures, such as bypass grafts or stenting.

Key risk factors suggesting significantly increasedcardiovascular risk include severe angina and heartfailure or previous myocardial infarction. Exercisetolerance is a useful and simple assessment and theability to climb a flight of stairs without anysymptoms usually indicates that day surgery willbe an acceptable option. Other risk factors,including diabetes and peripheral vascular disease,as well as the intensity of the surgical procedure,must also be considered, however.

Heart transplantation is still comparatively un-common, but are these patients suitable for daysurgery? While this may be the case in a stablepatient,17 there is little evidence available. Hearttransplant recipients are difficult to assess, sinceacute rejection can be difficult to detect and thedenervated, transplanted heart does not allow thepatient to feel the pain of angina.

Respiratory diseases

AsthmaMost asthmatics may safely undergo day surgery,provided they are well controlled with goodexercise tolerance. Elective surgery should bedelayed, if possible, if there has been a recentexacerbation, especially if this has necessitatedhospital admission or systemic steroids. Peakexpiratory flow is useful in assessing the severityof asthma, but other lung function tests should notusually be necessary. Asthmatic patients may beexpected to experience up to a five-fold increase inthe risk of postoperative respiratory events,19 butthese should have resolved well before the time ofdischarge home.

Non-steroidal anti-inflammatory drugs (NSAIDs)may trigger bronchospasm in about 5% of asth-matics, but many patients will have taken aspirin,ibuprofen, etc. in the past without ill effect.NSAIDs should not be withheld in these circum-stances. In the absence of any history, the risks andbenefits of NSAIDs must be balanced for theindividual patient.

Chronic obstructive pulmonary disease (COPD)COPD increases the risk of postoperative pulmonarycomplications, especially if the patients continueto smoke. However, most of these complicationsare relatively short-lived or minor and do notincrease the length of stay in recovery after day

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surgery.20 Postoperative complications are morelikely if patients have experienced respiratorysymptoms within the last month, especially if theyare symptomatic at the time of admission,21 whenelective surgery should probably be delayed.Smoking is common in patients with COPD andincreases both respiratory and wound complica-tions. Significantly reducing these requires patientsto stop smoking at least 6–8 weeks before surgery.Shorter periods are less beneficial, although a fewhours is enough to reduce carbon monoxide levelsand improve oxygen carriage. Smoking cessation isoften advocated as part of the pre-assessmentprocess, but is resource intensive and seldom veryeffective.

Exercise tolerance is again the most usefulassessment tool for respiratory disease. Spirometryis less helpful and not predictive of adverse eventsin asymptomatic individuals.17 Dyspnoea at rest oron minimal, indoor exertion, would usually be acontraindication to day surgery, although thesepatients may still be acceptable if the procedurecan be completed using regional or local anaes-thesia.

Acute upper respiratory tract infections (URTI)These infections are common, but day surgery willbe relatively safe if the URTI is mild and patientsare afebrile with no signs of lower respiratory tractinvolvement. Other sources of respiratory irrita-tion, such as smoking, asthma, COPD and theanticipated need for tracheal intubation shouldall be considered and may influence the decision topostpone surgery. Patients should be rescheduled ifthey are febrile or unwell, or if their surgery willinvolve the airway.

Obstructive sleep apnoeaPatients with obstructive sleep apnoea presentnumerous problems, including difficult trachealintubation and an increased incidence of hyperten-sion, dysrhythmias, sudden death, oxygen desa-turation, airway obstruction and the need forreintubation.17 Many of these cardiorespiratoryeffects are exacerbated by opioid analgesics, whichshould generally be avoided, consistent with goodday surgery practice. Regional anaesthesia mayhelp to reduce the need for opioids, although thereis little evidence that this is necessarily safer thangeneral anaesthesia.17 Day surgery may be accep-table in sleep apnoea if patients are established onnasal continuous positive airway pressure (nCPAP)which results in good control of symptoms and theyare proficient in using the device themselves. ThenCPAP device should then be worn for all post-operative sleep periods.

Unfortunately, it has been estimated that atleast 80% of patients with sleep apnoea do nothave a formal diagnosis and are therefore un-treated. It is obviously important to identifyand treat these patients preoperatively, althoughaccess to appropriate diagnostic tests can bedifficult.

Diabetes mellitus

Although the management of diabetic patientsoften focuses on peri-operative glycaemic control,it is the tendency for diabetes to induce disease invarious end-organs which is the more importantissue. Diabetic patients should be carefullyscreened to identify co-existing cardiovascular,renal or autonomic dysfunction. This will requirea careful history, supported by blood tests and ECG.Any abnormalities should subsequently be investi-gated and managed in their own right.

Diabetic patients should also be assessed todetermine the stability of their diabetic control.Random blood sugars are unhelpful, but examina-tion of recent blood and urinalysis results may bemore informative, while glycosylated haemoglobinprovides evidence of the stability during the pastfew months. Poor preoperative glycaemic controlincreases the likelihood of wound infection and alsoincreases the chances of peri-operative hyper- orhypoglycaemia, which are undesirable is daysurgery.

Stable diabetic day case patients are bestmanaged in a way that interferes as little aspossible with their usual regimen. Normal medica-tions, including metformin, should be continued upto, and including, the night before surgery.22

Patients should then omit their morning oralhypoglycaemic agent or insulin, be operated onfirst on the theatre list and aim to resume normaldiet and medication as soon as possible aftersurgery.23 This strategy is most likely to succeedafter relatively short procedures associated withminimal postoperative sedation, nausea and vomit-ing. Local or regional anaesthesia should be used,where possible; general anaesthesia may require amultimodal antiemetic regimen. While a similarapproach may be used for afternoon surgery,following a light breakfast and morning short-actinghypoglycaemic therapy, there is less time availableto ensure a full return to normal and diabeticpatients should preferentially be managed duringmorning sessions. Sliding scales and other morecomplex regimens have no advantages for stablepatients undergoing relatively minor surgery, butmay be required for more complex cases or in

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situations where the simple regimen has failed, forexample due to prolonged nausea.

Miscellaneous conditions

Patients with end stage renal failure on dialysis aregenerally unsuitable for day surgery, but may havesimple procedures performed under local anaes-thesia, including the formation of a fistula fordialysis.5 Day surgery is also contraindicated insevere liver disease, but milder cases should notpose any difficulties.5

Patients with epilepsy can usually be managed asday cases provided their condition is stable andwell controlled.5 When less stable, there is natu-rally some concern about the safety of sendingpatients home soon after surgery. However, if thefits are very frequent, it is likely that the patientand their carers will already be used to managingthese in the home environment.

Previous or family problems with anaesthesia,such as succinylcholine apnoea, difficult trachealintubation and malignant hyperpyrexia can allbe managed in the day case setting by usingappropriate techniques. Preoperative assessmentby an anaesthetist is vital to ensure the rightindividuals and equipment are available. Neuro-muscular disorders also require individual assess-ment by an anaesthetist but often do not precludeday surgery.

Patients with learning difficulties are oftenawkward to manage, but day surgery is generallytheir best option since they benefit from minimalseparation from their normal environment.

Chronic medications

Specific examples have been discussed previously,but many medications confer significant benefits andshould not be withheld on the day of surgery.Patients should be given clear advice at pre-assessment. Oral contraceptives should not routinelybe stopped before day surgery; the thromboembolicrisk from unwanted pregnancy is greater than that ofremaining on therapy. Different advice may berequired for specific procedures or higher riskpatients, however.

Specific advice, tailored to individual circum-stances, is required for patients on anticoagulants.This must balance the risks of peri-operativebleeding, interactions with drugs like NSAIDs andthe original indication for anticoagulation. Stop-ping anticoagulation, even temporarily, may behighly dangerous in patients with drug-elutingcoronary stents,24 although other patients may

benefit from temporary suspension of anticoagula-tion. If the intended period of anticoagulation isonly short, it is more logical to delay surgery untilthis treatment is no longer required.

Monoamine oxidase inhibitors (MAOIs) may stillbe required for severe depression. Stopping themmay provoke a life-threatening exacerbation of thedepression. Provided pethidine, cocaine and indir-ect-acting catecholamines are avoided, continuingMAOI therapy throughout the perioperative periodshould be safe.22

The use of herbal medication is increasing butpatients consider these harmless and rarely volun-teer that they are taking them. While most arerelatively benign, a few have important interac-tions with the coagulation system and should bestopped for a week before surgery.25 St. John’swort has multiple potential interactions and shouldalso be stopped well before surgery. Of therecreational drugs, only recent use of MDMA(‘‘Ecstasy’’) and cocaine should contraindicateelective surgery. Opioid abuse complicates painrelief and opioids should be avoided in recoveringaddicts.

Pre-assessment

Preoperative assessment is an essential componentof day surgery, not to ensure that all complicationsare avoided, but rather to ensure that rationalselection criteria are applied, that all co-existingconditions are discovered, investigated if necessaryand optimally treated, and to ensure that patientsare appropriately informed and prepared. Pre-assessment should ideally be combined with thesurgical outpatient appointment, but informationmay also be collected by questionnaire or tele-phone. The process is primarily clinical, relyingpredominantly on the patient history. Physicalexamination rarely uncovers findings which wouldradically alter the intended management or out-come, while blood tests and other special investi-gations have no value as screening tools. Insteadthese options should be used selectively to furtherinvestigate known problems.

All patients scheduled for procedures which canbe done as a day case should be referred for pre-assessment (unless there is a specific surgicalcontraindication in a given patient), at which pointtheir suitability on medical and social grounds canbe determined. Pre-assessment is a nurse-runprocess, but a select few patients will requirespecialist review by a senior day case anaesthetist.It may also be appropriate that the peri-operativemanagement of some of the more complex day case

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patients be restricted to specialist and experiencedsurgeons and anaesthetists.

Conclusions

Day surgery selection criteria have already ex-panded considerably and should no longer be basedon conservative and arbitrary limits. As thepopulation ages, obesity, diabetes and cardiovas-cular disease all become more prevalent, and asmore people live alone, the challenges for daysurgery will increase further. North Americanexperience suggests that these patients will stilldo well as day cases. Prolonged hospitalisation is nolonger the best option and may expose patients tothe risks of infection, dehydration, sleep depriva-tion and poor pain control. This should only becontemplated where there is some tangible bene-fit. With appropriate support, many patients will behappier and more comfortable in their own homes.

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21. Warner DO, Warner MA, Barnes RD, Offord KP, Schroeder DR,Gray DT, et al. Perioperative respiratory complications inpatients with asthma. Anesthesiology 1996;85(3):460–7.

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23. British Association of Day Surgery. Day surgery and thediabetic patient (revised edition), London; 2004. Availablefrom /www.bads.co.ukS.

24. Howard-Alpe GM, de Bono J, Hudsmith L, Orr WP, Foex P,Sear JW. Coronary artery stents and non-cardiac surgery.Br J Anaesth 2007;98(5):560–74.

25. British Association of Day Surgery. Perioperative use ofherbal medicine products, London; 2006. Available from/www.bads.co.ukS.