ARTICLE IN PRESS

Current Anaesthesia & Critical Care (2007) 18, 188–192

0953-7112/$ - sdoi:10.1016/j.c

E-mail addr

www.elsevier.com/locate/cacc

FOCUS ON: DAY CASE

General anaesthesia for day surgery:Preventing the problems

Sarah Lloyd

Department of Anaesthesia, St James University Hospital, Becket Street, Leeds, LS9 7TF, UK

KEYWORDSIntravenousanaesthesia;Propofol;Inhalationanaesthesia;Desflurane;Sevoflurane;Laryngeal maskairway

ee front matter & 2007acc.2007.07.002

ess: Sarah.Lloyd@leeds

Summary The ideal day case anaesthetic should provide a rapid and smoothinduction with good operating conditions, rapid recovery and minimal postoperativecomplications. No current agent is ideal, but careful use of the available choices canstill produce excellent results.

No single technique has been shown to give consistently superior recovery andachieving optimal results relies on a combination of factors, including provision ofeffective non-opioid analgesia, use of supplemental fluids, minimising emetogenicsupplements and careful titration of anaesthesia to effect. The art and skill of theindividual anaesthetist are as important in this respect as their actual choice ofanaesthetic drugs.& 2007 Published by Elsevier Ltd.

Introduction

The essential characteristics of good day caseanaesthesia are that it should be safe, with apleasant induction and high quality surgical condi-tions, rapid recovery and few postoperative pro-blems. It also needs to be cost-effective and topromote efficient patient flow.

The ideal day case anaesthetic

The triad of general anaesthesia consisting ofhypnosis, analgesia and muscle relaxation was firstdescribed using a single agent. Modern balancedanaesthesia uses a combination of drugs to achievethis triad, although the use of a single agent, or at

Published by Elsevier Ltd.

th.nhs.uk

least a greatly reduced number of agents, is gainingin popularity.1 Patients undergoing day surgeryexpect high quality, rapid onset of anaesthesiaand a problem-free recovery, therefore the choiceof agents and techniques and the way they areemployed are of great importance.

Preoperative medication

Premedication for anxiolysis, using drugs such asbenzodiazepines, is not commonly employed inadult day surgical practice, as the effects of thesedrugs may continue into the postoperative periodimpairing recovery. While there is no evidence tosuggest that pharmacological anxiolysis delaysdischarge from hospital,1 impairment on psycho-motor testing in the postoperative period has beenshown.

ARTICLE IN PRESS

General anaesthesia for day surgery 189

Preoperative anxiety is commonly managed non-pharmacologically within the day care environ-ment. Patients and their carers are well informedabout all aspects of their care, using pre-preparedliterature. Medical and nursing staff take time toexplain procedures and answer questions. The flowof patients through the unit may be designed tominimise waiting times as much as possible andmany patients find distraction in the form ofwatching television, listening to music or readinguseful. There is often flexibility to change the listorder so that especially anxious patients, or thosewith special needs, are brought forward. However,pharmacological anxiolysis should not be withheldif it is considered to be beneficial in selected cases.

Other drugs may be indicated in the preoperativeperiod, including prophylaxis of acid reflux insusceptible patients and paracetamol or non-steroidal antiinflammatory drugs (NSAIDs) as partof an analgesic strategy.

Induction of anaesthesia

Propofol is the intravenous induction agent ofchoice for day surgery and is used for this purposeby the majority of anaesthetists in the UK. Itachieves smooth and rapid loss of consciousnesswith few side effects. Pain on injection is lesscommon with newer preparations and is greatlyreduced by the addition of lidocaine. Propofolinduction results in marked respiratory depressionand obtunds the airway reflexes; this can be usefulin rapidly achieving control of the airway.

Inhalational induction using sevoflurane is analternative method of induction of anaesthesia.The use of a vital capacity technique with a circuitprimed with 8% sevoflurane in 75% nitrous oxideproduced a faster loss of consciousness comparedto propofol induction,2 but with similar sideeffects, recovery times and patient satisfaction.Tidal breathing techniques, in which 8% sevofluraneis inspired from the outset, are simpler to use andstill give excellent results in most cases.3 Inhalationinduction is used regularly by some anaesthetists,

Table 1 Comparison of some physical properties of thanaesthesia.

Agent Partition coefficient

Blood/gas Oil/gas

Isoflurane 1.4 97Sevoflurane 0.69 53Desflurane 0.42 19N2O 0.47 1.4

but enjoys more widespread occasional usage forpaediatric patients and adults with anxiety or aphobia of needles. However, the technique prob-ably deserves wider use and has been shown to bemore popular with patients than many anaesthe-tists believe.4

Rapid sequence induction may need to beemployed for patients at especially high risk ofgastro-oesophageal reflux; such cases are beingencountered more commonly in day surgery asobese patients and those with significant co-morbidities are no longer excluded. Other induc-tion agents have no real place in day caseanaesthesia, since they are associated with tooprolonged a recovery or an unacceptable incidenceof postoperative nausea and vomiting (PONV).

Maintenance of anaesthesia

The choice of maintenance technique needs to bebased on combining optimal surgical conditionswith rapid recovery and a low incidence ofproblems, such as poor analgesia or PONV. Thetechniques available consist of using inhalational orintravenous agents or a combination of these withor without concomitant use of nitrous oxide (N2O).

Inhalational agents

Halothane and enflurane, although widely used inthe past, are now rarely employed in anaesthesiafor day surgery in the UK. In practice, the choice ofinhalational agents rests between isoflurane, sevo-flurane and desflurane, and some of their proper-ties are shown in Table 1. An ideal agent wouldhave a low blood /gas partition coefficient, ensur-ing rapid uptake, good controllability and fastrecovery, be sufficiently potent with a high oil/gas partition coefficient and low MAC to allow it tobe used with enhanced oxygen concentrations andN2O and be excreted without metabolism (orharmful metabolites).

Other factors influencing choice of agents in-clude an irritant effect on airways with isoflurane

e inhaled agents most commonly used in day case

MAC (adults) (%) Metabolism (%)

1–1.2 0.21.4–2.5 o55–7 0.02

105 0

ARTICLE IN PRESS

S. Lloyd190

and desflurane, making inhalational induction verydifficult and the requirement of special equipmentin the form of a direct metering vaporiser fordesflurane. There are significant differences in costbetween agents, with sevoflurane and desfluranebeing more expensive than isoflurane, however thisdifferential has been reduced as generic prepara-tions become available.

Nitrous oxideNitrous oxide is widely used as an adjunct to morepotent anaesthetics, contributing to improvedcardio-respiratory stability, rapid emergence anda reduced incidence of awareness.5 It may increasethe incidence of PONV where the risk is high andshould not be used in circumstances where expan-sion of air filled spaces (due to the more rapiddiffusion of nitrous oxide than nitrogen) may be aproblem. Use of nitrous oxide reduces the require-ment for the more potent and expensive volatileagents and therefore influences the cost of anaes-thesia.

Intravenous anaesthesiaPropofol has a pharmacokinetic profile that is wellsuited to day case anaesthesia, as it provides rapidrecovery due to its short redistribution (1–2min)and elimination (1–5 h) half lives. Propofol can beused by infusion for the maintenance of anaesthe-sia, either with nitrous oxide or as total intravenousanaesthesia (TIVA), where the patient breathesoxygen in air and a short acting analgesic, such asalfentanil or remifentanil, provides analgesia.Infusion techniques using propofol require thatthe rate is adjusted to maintain plasma concentra-tions and therefore depth of anaesthesia. Theinfusion rate can be controlled using a manualregime or by utilising a computer controlled pump.A target controlled infusion (TCI) utilises analgorithm to deliver a chosen plasma concentrationto the patient and adjusts the pump to maintainthat concentration as redistribution and elimina-tion occur. A commercial system is available(Diprifusors), but this requires the use of specialpre-filled syringes that adds to the expense of thistechnique. Generic forms of TCI, which can be usedwith any form of propofol, will address this issueand are now available in parts of Europe. There isdebate as to whether the use of TCI is superior tomanual control in delivering a constant depth ofanaesthesia, but the former is somewhat easierto use.

AnalgesiaA balanced multimodal approach should be em-ployed with the aim of producing good intra- and

postoperative pain control with minimal sideeffects. Local anaesthetic infiltration (or nerveblocks) may be undertaken before surgical stimu-lus, this may reduce the amount of opiates requiredpostoperatively and thus their associated morbid-ity, while the total amount of inhalational orintravenous anaesthetic may also be reduced,leading to quicker emergence. Paracetamol orNSAIDs can be given by mouth preoperatively andwill contribute to analgesic requirements in theearly postoperative period.

For all but the most minor procedures, it iscommon to use an opioid (particularly fentanyl) aspart of the anaesthetic technique to improveintraoperative conditions and in the assumptionthat it will contribute to postoperative analgesia.Adequate intraoperative conditions can usually beachieved by small increases in the anaestheticconcentration, while local anaesthetic woundinfiltration and NSAIDs provide good postoperativeanalgesia. Fentanyl does not improve postoperativepain control, although it does produce a significantincrease in the incidence and severity of PONV.6–8

The use of intraoperative morphine is likely to beeven worse.

Opioid supplements are more likely to be usedin conjunction with intravenous anaesthesia,where the antiemetic effect of propofol will reducetheir potential for PONV. Alfentanil and morerecently remifentanil9 show favourable recoverycharacteristics when used as an infusion as part ofTIVA. In using infusions of ultra-short acting drugs,such as remifentanil, it is essential to plananalgesia for the immediate postoperative periodin order to prevent pain being a problem in therecovery room. Even remifentanil can increasePONV and the short-acting beta blocker, esmolol,has been used as an alternative to controlcardiovascular stability.10

Muscle relaxationFor many day case procedures, formal musclerelaxation using neuromuscular blocking drugs isnot necessary. As the scope of day surgeryincreases, however, more procedures requiringmuscle relaxation are being undertaken.

The use of the depolarising muscle relaxantsuccinylcholine (suxamethonium) has a place wherea rapid sequence induction is indicated; however,its side effect profile—in particular muscle pains—may be a problem in day case patients. Rocuroniummay be a reasonable alternative if difficult intuba-tion is thought to be unlikely. The choices of non-depolarising muscle relaxant will depend on theanticipated duration of surgery and whether re-versal is planned. Reversal of non-depolarising

ARTICLE IN PRESS

General anaesthesia for day surgery 191

muscle relaxants with neostigmine has beenimplicated in causing PONV, although a recentreview suggests that its use does not increasePONV during the first 24 h after surgery.11

Tracheal intubation can also be achieved withoutmuscle relaxants after an induction dose ofpropofol combined with fentanyl, alfentanil orremifentanil or under deep inhalation anaesthesia.

Airway and ventilationA large proportion of day case procedures aremanaged using the laryngeal mask airway (LMA)with spontaneous or mechanical ventilation. Thereis good experience of the LMA in a wide variety ofsituations. The use of a LMA gives protection fromsoiling of the trachea from above, which isimportant for dental or nasal procedures. It doesnot protect against the aspiration of regurgitatedstomach contents, however. Tracheal intubationleads to increased complaints of postoperative sorethroat, also the time taken for the anaesthetist toextubate patients may add to the ‘turn around’time between cases. There are now a vast profu-sion of new supraglottic airways which are intendedas an alternative to the LMA. To date, nonehave any obvious advantage over the well-estab-lished LMA.

Comparison of techniques

Recovery characteristicsThere are no standard tests for assessing recoveryfrom anaesthesia; clinical assessment is used inroutine practice, with more sophisticated testsbeing reserved for studies comparing anaesthetictechniques. In day surgical practice there are threetimes that are of particular interest; the time ofemergence from anaesthesia—identified by eyeopening or obeying commands; the time the patientis fit to leave the postanaesthetic care unit (PACU)and the time they are fit to be discharged home.Actual time to discharge home is a poor indicator,as this may be affected by practical considerations,such as the availability of an escort or transportarrangements.

A recent meta-analysis compared the recoveryprofiles of propofol, isoflurane, sevoflurane anddesflurane.12 Emergence times were similar afterisoflurane and propofol, a little faster after sevo-flurane and fastest of all after desflurane, althoughthe actual differences were no more than 1–2min,with a lot of variability between individual studies.Later recovery endpoints seemed to differ even lessbetween the various agents, although isofluraneappeared to result in a delay of approximately

15min in home-readiness.12 The clinical signifi-cance of any of these differences is doubtful,however.

It is important to also consider the effect of theanaesthetic technique on problems encounteredduring the first 24 h after surgery when PONV, pain,drowsiness, somnolence, dizziness, headache andsore throat may all be unpleasant for day casepatients. Patients receiving propofol for the main-tenance of anaesthesia had a lower incidence ofPONV compared to those managed with techniquesincluding inhalational agents13 and the requirementfor antiemetic therapy was also somewhat re-duced.12 However, the clinical significance of thelate antiemetic effect of propofol has been ques-tioned.14 Practitioners using inhalation-basedanaesthesia probably need to take more care inorder to reduce PONV to acceptable levels, such asby the avoidance of opioids and, perhaps, the useof prophylactic antiemetics. Administering as littleas one litre of intravenous fluid is also a simple andinexpensive way of significantly reducing PONV,dizziness and somnolence in the first 24 h aftersurgery.15

Cost effectiveness and efficiencyThe benefits of reduced recovery times can onlybe translated into cost savings if either staffnumbers can be reduced or more patients can betreated by the existing team. There may also beadditional cost implications for techniqueswhere specialist equipment is required, for in-stance infusion devices for TIVA or TCI, ornew vaporisers for inhaled anaesthetics. Compar-ison of the costs of drugs depends not only onthe amount used but also any wastage that mayoccur, for example with TIVA techniques unuseddrug is discarded in the syringe at the end of eachcase.16

Bypassing the PACU, by transferring patientsdirectly to the second level recovery or wardfacility (‘‘fast tracking’’), is advocated as a methodof cost saving in some centres in the USA. In onestudy, 90% of patients receiving desflurane and 75%of those receiving sevoflurane met the criteria forfast tracking compared to only 25% after propofol,suggesting the recovery characteristics of thenewer volatile anaesthetics to be superior in thiscontext.17 However, others have failed to detectsuch great differences and it is likely that theremay be only very limited benefit to fast trackrecovery in the UK.18 Efficiency in day surgicaltheatres also depends on minimising the timebetween cases and this ‘‘turnover time’’ may varywith different techniques.

ARTICLE IN PRESS

S. Lloyd192

Conclusions

No single anaesthetic technique has been shown tobe clearly superior for day case surgery, thereforethe choice of technique must take other factors intoaccount. The experience of the anaesthetist using agiven technique is important and a learning curveshowing improvements in recovery times and theincidence of side effects has been identified,19 evenwhen a standard protocol is used. The availability ofequipment and other factors in the environment inwhich anaesthesia is to be delivered may make sometechniques more suitable for certain circumstances.In addition to the advances in ‘science’ with newdrugs and delivery systems, the practice of the ‘art’of anaesthesia is still important to deliver the verybest quality care for our patients.

References

1. Smith AF, Pittaway AJ. Premedication for anxiety in adultday surgery. Cochrane Database Syst Rev 2000(3):CD002192.

2. Philip BK, Lombard LL, Roaf ER, Drager LR, Calalang I, PhilipJH. Comparison of vital capacity induction with sevofluraneto intravenous induction with propofol for adult ambulatoryanesthesia. Anesth Analg 1999;89(3):623–7.

3. Ghatge S, Lee J, Smith I. Sevoflurane: an ideal agent foradult day-case anesthesia? Acta Anaesthesiol Scand 2003;47(8):917–31.

4. van den Berg AA, Chitty DA, Jones RD, Sohel MS, Shahen A.Intravenous or inhaled induction of anesthesia in adults? Anaudit of preoperative patient preferences. Anesth Analg2005;100(5):1422–4.

5. Hopkins PM. Nitrous oxide: a unique drug of continuingimportance for anaesthesia. Best Pract Res Clin Anaesthesiol2005;19(3):381–9.

6. Shakir AAK, Ramachandra V, Hasan MA. Day surgery post-operative nausea and vomiting at home related to pero-perative fentanyl. J One-day Surg 1997;6(3):10–1.

7. Smith I. Avoidance of fentanyl reduces nausea and vomitingassociated with volatile induction and maintenance of

anaesthesia with sevoflurane (abstract). Anaesthesia 2007;62:309.

8. Sukhani R, Vazquez J, Pappas AL, Frey K, Aasen M, Slogoff S.Recovery after propofol with and without intraoperativefentanyl in patients undergoing ambulatory gynecologiclaparoscopy. Anesth Analg 1996;83(5):975–81.

9. Cartwright DP, Kvalsvik O, Cassuto J, Jansen JP, Wall C, RemyB, et al. A randomized, blind comparison of remifentanil andalfentanil during anesthesia for outpatient surgery. AnesthAnalg 1997;85(5):1014–9.

10. Coloma M, Chiu JW, White PF, Armbruster SC. The use ofesmolol as an alternative to remifentanil during desfluraneanesthesia for fast-track outpatient gynecologic laparo-scopic surgery. Anesth Analg 2001;92(2):352–7.

11. Cheng CR, Sessler DI, Apfel CC. Does neostigmine adminis-tration produce a clinically important increase in post-operative nausea and vomiting? Anesth Analg 2005;101(5):1349–55.

12. Gupta A, Stierer T, Zuckerman R, Sakima N, Parker SD,Fleisher LA. Comparison of recovery profile after ambulatoryanesthesia with propofol, isoflurane, sevoflurane and des-flurane: a systematic review. Anesth Analg 2004;98(3):632–41.

13. Sneyd JR, Carr A, Byrom WD, Bilski AJ. A meta-analysis ofnausea and vomiting following maintenance of anaesthesiawith propofol or inhalational agents. Eur J Anaesthesiol1998;15(4):433–45.

14. Tramer M, Moore A, McQuay H. Meta-analytic comparison ofprophylactic antiemetic efficacy for postoperative nauseaand vomiting: propofol anaesthesia vs omitting nitrous oxidevs total i.v. anaesthesia with propofol. Br J Anaesth 1997;78(3):256–9.

15. Yogendran S, Asokumar B, Cheng DC, Chung F. A prospectiverandomized double-blinded study of the effect of intrave-nous fluid therapy on adverse outcomes on outpatientsurgery. Anesth Analg 1995;80(4):682–6.

16. Smith I. Cost considerations in the use of anaesthetic drugs.Pharmacoeconomics 2001;19(5 Pt 1):469–81.

17. Song D, Joshi GP, White PF. Fast-track eligibility afterambulatory anesthesia: a comparison of desflurane, sevo-flurane, and propofol. Anesth Analg 1998;86(2):267–73.

18. Millar II. J. Fast-tracking in day surgery. Is your journey tothe recovery room really necessary? Br J Anaesth 2004;93(6):756–8.

19. Joshi GP, Jamerson BD, Roizen MF, Fleisher L, Twersky RS,et al. Is there a learning curve associated with the use ofremifentanil? Anesth Analg 2000;91(5):1049–55.