Modern day-case anaesthesia for children

British Journal of Anaesthesia 83 (1): 91–103 (1999)

Modern day-case anaesthesia for children L. J. Brennan Department of Anaesthesia, Addenbrooke’s NHS Trust, Cambridge CB2 2QQ, UK Br J Anaesth 1999; 83: 91–103 Keywords: anaesthesia, paediatric; analgesia, paediatric; anaesthesia, day-case; children

In recent years there has been a trend towards performing increasing amounts of surgery on children on a day-stay (ambulatory or outpatient) basis. Children make excellent candidates for day-case surgery as they are usually healthy, free of systemic disease and typically require straightforward, minor or intermediate surgical procedures. More than 60% of paediatric surgery in the USA is performed on an ambulatory basis35 and in the UK, the Royal College of Surgeons of England and the National Health Service Executive have estimated that 50% of all elective surgery, especially that in children, can be performed as day surgery.27 69 What has prompted this shift away from inpatient care? Undoubtedly, the main impetus has been economic as all healthcare systems have struggled to meet the ever increasing demands for healthcare without a commensurate increase in health budgets. Major cost savings and a reduction in waiting lists can result if common children’s procedures are changed from inpatient to day care.75 For example, in the Cambridge Unit, the costs for day-case circumcision are 46% of the inpatient equivalent. More controversially, further cost savings can accrue if an increase in day surgery is combined with closure of inpatient beds.59 Alternatively, transfer of cases to the outpatient sphere releases inpatient resources for those children requiring more complex surgical procedures. Apart from economic and operational benefits, day-stay management confers major advantages for the child and family. The psychological and emotional impact of inpatient admission cannot be overestimated. Behavioural problems, disrupted sleeping patterns, nocturnal enuresis and regression of developmental milestones are common after inpatient stay and are avoided by day surgical care.76 Disruption to family life of a child in hospital is also minimized by outpatient management. From a medical perspective, exposure to hospital acquired infection is decreased by day care60 which is particularly advantageous for immunocompromised children, such as oncological patients. Consistent provision of high-quality day surgical care is challenging. The criteria for judging the quality of the daycase service are minimal postoperative morbidity, low inpatient admission rates and high parental and child satisfaction. Achievement of these goals requires a multi-

disciplinary approach with the services of experienced and enthusiastic clinicians working in child-friendly and childsafe facilities. In addition, concise, unambiguous selection criteria, appropriate anaesthesia, scrupulous postoperative symptom control and clear communication with parents and community-based colleagues ensures successful outcome. These principles are enshrined in the 12 quality standards contained in the multidisciplinary report Just for the Day which is the UK blueprint for good practice in paediatric day-case management84 (Table 1).

Selection criteria To ensure the success of a children’s day-case programme, it is essential that unambiguous selection procedures are developed by the day unit director in collaboration with the admitting clinicians (Table 2). Four key areas need to be considered when developing these procedures.

The patient Most children are healthy and well-suited for day-case management. However, children with well-controlled systemic disease (e.g. asthma or epilepsy) are often suitable candidates, including some who are classified as ASA grade III.4 Caution is advised when considering children with inborn errors of metabolism for day surgery because of the dangers of symptomatic hypoglycaemia that may be associated with perioperative fasting. Similarly, glycaemic control may be difficult in insulin-dependent diabetics managed on a day-stay basis.2 Although complex congenital heart disease is always a contraindication to day-case management, children with uncomplicated lesions (e.g. small ventricular septal defect (VSD)) or surgically corrected defects which are asymptomatic may be suitable, provided antibiotic prophylaxis against bacterial endocarditis is used as indicated. A previously undiagnosed cardiac murmur is a common dilemma in paediatric day care. Particular attention should be taken when assessing children less than 1 yr of age with a murmur as a potentially serious lesion may not have yet been manifest.49 Deferment of the procedure may be necessary to allow full cardiological appraisal. Deciding the appropriate management of a child with a

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Table 1 Quality standards for paediatric day-case management (adapted with permission from Thornes)84

Table 2 Exclusion criteria for paediatric day-case management Age and medical exclusions d Ex-preterm infant ,60 weeks post-conceptual age d Inadequately controlled systemic disease (e.g. epilepsy, asthma) d Active viral or bacterial infection (especially respiratory) d Complex congenital heart disease d Uninvestigated cardiac murmur d Diabetes mellitus d Sickle cell disease Surgical and anaesthetic exclusions d Inexperienced surgeon or anaesthetist d Prolonged procedure (.1 h) d Significant risk of excessive perioperative haemorrhage d Opening a body cavity (excluding laparoscopy) d Difficult airway d Sleep apnoea d ?Malignant hyperthermia susceptibility d Pain unlikely to be relieved by oral analgesia after discharge home Social exclusions d Parents incapable or reluctant to care for child at home d Unsupported single parent with numerous children d Inadequate housing conditions d No telephone d Inadequate postoperative transport arrangements (public transport unacceptable) d Long journey home after discharge (.1 h)

1. An integrated admission plan should be formulated to include preadmission, day of admission and post-admission care with planned transfer of care to community services. 2. Child and parent should be offered preparation before and during the day of admission. 3. Parents should be provided with specific written information. 4. Child should be admitted to a designated day-case area and not mixed with acutely ill inpatients. 5. Children should not be admitted or treated alongside adults. 6. Specifically designated day-case staff should care for the child. 7. Only staff with paediatric and day-care experience should manage the child. 8. Care should be organized so that every child is likely to be discharged within the day. 9. The building equipment and furnishings should comply with children’s safety standards. 10. The environment should be child-friendly. 11. Essential documentation should be completed before the child’s discharge to ensure efficient after care and follow-up. 12. Paediatric nursing support should be available to children at home.

respiratory infection in day care is difficult. It has been estimated that 20–30% of children have a ‘runny nose’ for a large proportion of the year.31 Many of these children have benign, non-infectious seasonal rhinitis or their symptoms are caused by infected adenoids and are perennial. Cancelling these patients confers no clinical benefit. Alternatively, coryzal symptoms may be a prelude to a more severe upper or lower respiratory tract infection, childhood exanthema or even a life-threatening condition such as bacterial meningitis. Anaesthesia in the presence of significant respiratory infection may produce increased perioperative respiratory complications,87 particularly in the infant age group44 and if the trachea is intubated.13 The other unquantified concern is the incidence of myocarditis associated with the viraemic phase of some illnesses.8 There is no one correct approach to these problems and each child must be assessed on an individual basis by an experienced anaesthetist. All children with moderate or severe respiratory infections should be postponed. Clinical indicators of severity include productive cough, purulent nasal secretions and systemic features of infection, including fever, malaise and irritable behaviour. If the respiratory infection is mild with non-productive cough, clear nasal secretions and a constitutionally well child, it may be reasonable to proceed. However, even with mild symptoms, a low threshold for cancellation should apply in children less than 1 yr of age if there is any evidence of bronchospasm or if the procedure requires tracheal intubation. If the procedure is postponed, some authors recommend a 2-week deferral if the upper respiratory tract is affected but 4 weeks if there is evidence of lower respiratory tract involvement.2 31 The lower age limit for day-case management depends on a variety of factors, including post-conceptual age, experience of the anaesthetist and the facilities of the day unit. A healthy, term infant may be safely anaesthetized for minor procedures such as examination of the eyes as a daycase if suitably qualified anaesthetic personnel are involved and there is access to inpatient neonatal care if required.53

Preterm or ex-preterm infants are not suitable candidates for day surgery because of potential complications, such as postoperative apnoea and problems with body temperature control. The age at which an ex-preterm infant may be safely managed as a day case is unknown. Each child needs to be assessed individually but factors such as an ongoing history of apnoeic episodes, presence of anaemia and bronchopulmonary dysplasia are important in the decision making process. Most authorities will not consider daycase anaesthetic management for preterm infants less than 50 weeks post-conceptual age or even older if the infant still exhibits signs of chronic lung disease.16 Outside specialist centres, the lower age limit for day surgery is often much higher, with 6 months or even 1 yr being common thresholds in UK practice. This reflects the availability of facilities and equipment appropriate for infants in addition to the potential infant workload.

The procedure A wide range of surgical and non-surgical procedures are appropriate for day-case management (Table 3). Body surface procedures without major encroachment on a body cavity are most suitable. Procedures should be associated with minimal bleeding and normally take no more than 1 h to complete. Postoperative pain should not be severe and must be manageable with oral analgesia after discharge home. Tonsil and adenoid surgery is a highly controversial area of day-case practice. Although some countries have performed these procedures on a day-stay basis for many years, UK practice has generally been more conservative. In 1985, the Royal College of Surgeons of England published guidelines for day surgery in which they concluded that adenotonsillar surgery was an unsuitable day-case pro-

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Table 3 Range of procedures suitable for paediatric day-case management

associated with tracheal intubation in day surgery patients. Post-extubation stridor, particularly in younger children, was a real problem in the past but is much less common in contemporary practice with modern tracheal tubes, which are less likely to induce mucosal oedema. In addition, the increasing use of the laryngeal mask airway has superseded many of the previous indications for intubation (see below). Susceptibility to malignant hyperthermia (MH) has been seen previously as a contraindication to day-case management. However, a retrospective review of MH susceptible children concluded that day care could be contemplated safely in this condition.96

General surgery Hernia repair (inguinal, epigastric, umbilical) Excision of hydrocele Endoscopy (gastric, rectal, colonic) Ingrowing toe nail excision Urology Orchidopexy Circumcision Preputial adhesions Cystoscopy Minor hypospadias Opthalmology Strabismus correction Lacrimal duct probing EUA Dental Extractions Restorations ENT Myringotomies Nasal/aural foreign body removal ?Adenotonsillectomy Orthopaedics Plaster case application or removal Arthroscopy Removal of metalwork Plastic surgery Prominent ear correction Excision skin lesions Suture removal/dressing changes Medical Bone marrow sampling Lumbar puncture, intrathecal medication Radiotherapy CT, MRI and other scans Interventional radiology/cardiology

The family Day-case management does not suit the social circumstances of all children and their families. Unduly anxious parents and single parents with several other children may feel unable to cope with a child returning home so soon after surgery. Community paediatric nurses may be usefully deployed in this situation to support parents and so avoid the need for inpatient admission.2

Preoperative screening and investigations An efficient system of preoperative assessment well in advance of the day-case procedure is advantageous for the child and family. Preventable cancellation is avoided and by completing much of the administrative process before the day of surgery, the admission process is facilitated, decreasing stress levels for the child and parent. The daycase service also benefits from this approach as wastage of operating time and resources associated with cancellation are minimized. Successful screening can be achieved in a variety of ways. Nurse-led assessment is becoming increasingly popular in the UK.41 66 The parent and child are sent by the surgeon to the day unit where the parent completes a questionnaire detailing the child’s medical history (Fig. 1). An experienced day unit nurse then reviews the questionnaire, clarifying any ambiguities with the parent. The nurse sorts children into those who are suitable for day surgery, those who are clearly unsuitable and those who need further assessment by a clinician before a final decision can be made. An experienced clinician, usually a consultant anaesthetist who works in the day unit, arbitrates on the borderline patients. For suitable cases, a date can be fixed for surgery and further advice given to the parent by the day surgery nurse, reinforced by written preoperative instructions and an information leaflet (Fig. 2). Telephone screening, popular in North America, can be useful, particularly if the child was seen for the surgical consultation at a location distant from the day unit. The same questionnaire method can be used, with borderline cases being invited to attend the day unit for further assessment. A second telephone call made 48 h or less before surgery allows a check of the child’s present state

cedure.28 Haemorrhage is the most feared complication and several studies have established that this is most likely to occur within 4–8 h after operation.50 Pain and postoperative vomiting are also major problems after adenotonsillectomy with some series reporting a 70% incidence of vomiting.26 However, UK attitudes are changing, with increasing reports testifying to the safety of day-case adenoidectomy47 and tonsillectomy.83 Successful day-case management of these cases involves careful case selection, excluding children less than 3 yr of age and those with a history of obstructive sleep apnoea. Families who lack private transport, a telephone or who live more than a 1-h drive from hospital should also be excluded.62 Perioperative care should involve an extended postoperative observation period in the day unit, watching for signs of haemorrhage. Optimal pain and vomiting control can be achieved by liberal use of NSAID, judicious use of opioids and prophylactic antiemetics.12

Anaesthetic considerations Even with modern agents, prolonged general anaesthesia is associated with prolonged recovery and complications such as vomiting, which may result in increased inpatient admission rates. For these reasons, many units avoid procedures which consistently take more than 1 h to complete. Concern is sometimes expressed about the problems

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Fig 1 Example of a preoperative questionnaire (reproduced with permission from Brennan9).

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Fig 2 Example of an information leaflet for children’s day surgery (reproduced with permission from Brennan9).

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of health, and important issues such as fasting instructions can be re-emphasized. All children should be seen by the operating surgeon and anaesthetist on the day of surgery. Both clinicians should conduct an appropriate physical examination with the anaesthetist focusing on cardiorespiratory fitness, particularly the presence of respiratory infection, which may contraindicate proceeding that day. Routine preoperative investigation of children before day surgery is unnecessary, as the majority of children presenting for day surgery are healthy.32 Although the incidence of anaemia is higher among infants, there is little evidence that this affects management or outcome of children undergoing day-case procedures.52 Sickle cell screening remains one of the few commonly performed investigations in UK paediatric day-case practice, although the need for this approach has been challenged for adult patients.20

This approach improves perioperative behaviour and minimizes the risk of hypoglycaemia without increasing the risk of pulmonary aspiration.67 Parents must be made aware of the dangers of prolonged starvation, with the emphasis that clear fluids should, rather than can, be given until 3 h before operation.

Anaesthetic management Premedication Sedative premedication is not used routinely in paediatric day-case practice. In the past, this was because the traditional premedicants were rejected as unsuitable because of excessive postoperative sedation or in the case of opioids, unacceptable emetic side effects.79 The current view is that good psychological rather than pharmacological preparation of the child together with parental presence at induction is optimal for the majority of children. However, some groups of children benefit from preoperative sedation before day surgery. These include the unduly anxious child, the child presenting for repeated procedures at short intervals and those with learning difficulties in whom it may be difficult to gain a rapport. In recent years, considerable interest has been focused on the use of midazolam for sedating these selected groups of children. The main advantage claimed for midazolam premedication is that it does not delay recovery after day surgery and is not associated with an increased incidence of inpatient admission. Oral administration is most popular, with a dose of 0.5 mg kg–1 acting within 10–30 min to produce a calm, cooperative child.62 However, some workers have reported that higher doses (0.75 mg kg–1) may delay recovery and produce postoperative agitation.17 An important practical point is that the standard formulation of midazolam is very bitter and to make it more acceptable to children it should be added to a palatable vehicle such as a small volume of sweet drink or paracetamol elixir. Other routes of administration for midazolam have been described, including rectal and nasal,18 19 but their use often involves a degree of restraint and may be associated with unpleasant side effects (e.g. nasal stinging and coughing).43 Anticholinergic premedication still has its advocates in day-case practice, particularly before inhalation induction in smaller children. Oral atropine (up to 40 µg kg–1) may be useful in this situation. However, routine anticholinergic premedication in older children has not been shown to improve induction conditions and is probably unnecessary.92

Psychological preparation Careful psychological preparation of the child before daycase admission is essential for several reasons. First, the interval between admission to the day unit and anaesthetic induction is usually short, allowing little time for orientation of the child to the day’s events. Second, sedative premedication is not commonly used for day-case patients and so careful preparation of the child takes on added importance. Many centres encourage children and their families to participate in a pre-admission programme in advance of the day-case procedure. Such programmes, which use play simulation, video presentations and a visit to the day unit, have been found to improve the perioperative behaviour of children. Long-term behavioural benefits have been demonstrated in children who have received an interactive teaching book before day-case admission.48 However, sceptics have suggested that parents who take advantage of preoperative programmes are often those whose level of education, motivation and understanding renders such formalities unnecessary for their children.72

Fasting regimens It is important to avoid prolonged preoperative starvation before day surgery as at best it produces an irritable, uncooperative child and at worst it may be associated with significant hypoglycaemia in some infants. Interestingly, parents are also at risk from prolonged fasting, with one study showing that 85% of parents fast alongside their children.89 Liberalized fasting regimens, particularly for clear fluids, are now well established. A common starvation regimen is illustrated below: d d d

Cutaneous anaesthesia for venepuncture Since the introduction of local anaesthetic skin preparations, painless venepuncture has become a reality and has vastly increased the use of i.v. induction for paediatric day cases. The two available products are tetracaine gel (Ametop) and an eutectic mixture of lidocaine and prilocaine (EMLA). EMLA must be applied for at least 60 min to achieve

6 h for solids, milk (including formula feeds for infants) 4 h for breast-fed infants 3 h for clear fluids (includes water, squash, carbonated drinks, black tea or coffee).

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consistently painless venous cannulation, whereas tetracaine gel has the advantage of a more rapid onset time (45 min) and less tendency to produce venoconstriction.22

Propofol has several characteristics that make it suitable for day-case use. Induction is usually smooth in unpremedicated children as long as a sufficiently large dose is used (up to 4 mg kg–1).58 As propofol very effectively obtunds upper airway reflexes, it facilitates easy and rapid insertion of the laryngeal mask airway (LMA). In addition, its rapid recovery characteristics are particularly advantageous in older children in whom it may allow more rapid discharge home than if thiopental was used.73 Pain on injection of propofol, its main drawback, can be minimized by using either a large antecubital vein or by mixing lidocaine (0.2 mg kg–1) with propofol, immediately before use.11

Pre-induction techniques Very occasionally, it may be necessary to provide last minute preoperative sedation to a very uncooperative child. In this situation, and with parental consent, an i.m. sedative may be administered. Ketamine in low doses (2 mg kg–1) has been found to be useful with an onset time of 3–5 min in young children. Recovery is not prolonged with this technique and emergence delirium does not seem to occur.33 Extreme caution is recommended when considering this technique in older children as undoubtedly considerable physical restraint may be required to administer an i.m. injection in this age group. A recent review of this topic advises that if an older child refuses to cooperate with treatment, the procedure should be deferred and counselling of the child and its parents ensue.81

Maintenance A maintenance technique using nitrous oxide, oxygen and a volatile agent is entirely satisfactory for most paediatric day-case anaesthetics. There seems to be little to choose between the long established volatile agents. For example, the slightly lower blood:gas solubility coefficient of isoflurane compared with halothane does not result in clinically significant differences in recovery time for shorter procedures (less than 1 h) typical of day surgery.31 Sevoflurane maintenance results in initial emergence from anaesthesia that is 33% more rapid than with halothane. However, disappointingly, a three-fold greater incidence of emergence agitation with sevoflurane results in discharge times that are identical to halothane.38 Similar problems have been described with desflurane maintenance.31 Total i.v. anaesthesia (TIVA) using propofol has definite advantages for some paediatric day-case procedures. For patients at high risk of vomiting (e.g. after strabismus correction), propofol maintenance has been shown to have very significant antiemetic effects.90 Rapid, clear-headed awakening associated with propofol maintenance is particularly beneficial after day-case ENT and ophthalmic procedures.55 The pharmacokinetics of propofol in children are different from those in adults. A three-compartment model is applicable to children with a volume of distribution that is 50% larger than in adults. In addition, clearance of propofol is up to twice that of adults. The clinical consequences of these pharmacokinetic differences are that higher initial bolus doses are needed to reach a given blood concentration and higher infusion rates are needed to maintain steady state blood concentration.55 It is clear that our knowledge and experience of TIVA with propofol in children is not as advanced as in adult practice and there is still much pharmacological and clinical research needed to advance the use of this technique in paediatric practice.

Induction Induction via the i.v. or inhalation route is suitable for paediatric day cases. The choice depends on the needs of the individual child, with the main goal being to produce smooth, atraumatic induction. Whichever technique is used, encouraging parental presence at induction can be very helpful for the child and anaesthetist.34 However, it is important to identify unduly anxious parents as they may make their child even more upset during the induction period.6

Inhalation techniques Inhalation induction is particularly suitable for the needlephobic patient or those children with difficult venous access. Transparent face masks coated with food flavourings can improve the acceptability of this technique for anxious children. Although halothane has been the gold standard inhalation induction agent for many years, sevoflurane is rapidly becoming the first-choice volatile agent for this purpose in the USA and Europe. Sevoflurane has a pleasant smell, non-irritating airway properties and a rapid onset of action.14

I.v. techniques I.v. induction has become increasingly popular since the introduction of local anaesthetic skin preparations. There is also some evidence that i.v. induction is less psychologically disturbing to children than inhalation methods.42 The choice of induction agent rests between thiopental and propofol. In unpremedicated children, large doses of thiopental (5–6 mg kg–1) are needed to ensure satisfactory induction. Compared with propofol, thiopental is associated with a slightly delayed initial recovery from anaesthesia but in younger children (less than 5 yr of age) discharge times for day cases are identical.93

Airway management The laryngeal mask airway (LMA) has transformed airway management in recent years, and has numerous advantages for day-case anaesthesia in children.37 In experienced hands, tracheal intubation can be avoided for nearly all of the

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usual day-case procedures by the use of the LMA, so avoiding the use of neuromuscular blocking drugs and problems such as extubation stridor. Head and neck procedures such as strabismus correction, adenotonsillectomy, dental surgery and prominent ear correction can be managed successfully using the reinforced version of the LMA. Concerns about contamination of the airway with blood and secretions when the LMA is used appear to be unfounded in studies of LMA use for oral surgery.25 Propofol appears to be the optimal i.v. induction agent to facilitate easy insertion of the LMA77; problems can occur if thiopental is used as barbiturates heighten the sensitivity of laryngeal reflexes. The alternative is insertion under deep inhalation anaesthesia. Timing the removal of the LMA in children in contentious. Some studies have shown that less airway complications occur if the LMA is removed with the child deeply anaesthetized,88 whereas others recommend the safest option in procedures such as oral surgery and adenotonsillectomy is to leave the LMA in situ with the cuff inflated until the child is fully awake.93

potential for side effects, especially interference with motor function and early ambulation.

Topical Local anaesthetic creams, in particular EMLA, have been used as the sole anaesthetic technique before myringotomies7 and division of preputial adhesions.46 Topical tetracaine eye drops provide excellent analgesia after strabismus surgery91 and lidocaine ointment is a useful analgesic after circumcision.85 Parents can continue with these topical techniques after the child is discharged home.

Infiltration Wound infiltration with local anaesthetic is simple to perform and very effective, and the opportunity to use this valuable technique in children’s day surgery should never be neglected. Besides its use in conjunction with general anaesthesia, many older children can have superficial procedures such as naevi removal or even otoplasty performed successfully under infiltration anaesthesia alone. Acceptance of the technique can be enhanced by using local anaesthetic creams in advance of infiltration, warming the local anaesthetic solution before use, using very fine needles (25- or 27-gauge) and injecting the local anaesthetic slowly to decrease discomfort from tissue distension.

Fluid therapy Day-case procedures are not usually associated with significant fluid losses, and with more liberal starvation regimens, preoperative dehydration should not be a problem. However, there is a place for perioperative i.v. hydration in children’s day surgery in some situations. d

d

d

Peripheral nerve block A wide range of peripheral nerve blocks are potentially applicable to paediatric day surgery, but in practice only a few are used commonly. Penile block. This block is becoming the favoured local analgesic technique after circumcision, minor hypospadias surgery and other penile procedures. Various techniques of blocking the dorsal penile nerves are described, including midline and paramedian approaches.51 Both methods involve depositing 0.5% bupivacaine without epinephrine deep to Buck’s fascia at the base of the penis. The single injection midline technique is associated with an increased incidence of failed block because of the inability of local anaesthetic to diffuse in the subfascial compartment because of septae. Damage to dorsal penile vessels and intravascular/intracorporeal injection of local anaesthetic (with risk of toxicity) may also occur. These problems are much less frequent with the paramedian approach in which two injections are made either side of the midline. A simpler approach to penile block is subcutaneous infiltration of plain bupivacaine around the base of the penis. Excellent results have been reported with this technique with no reports of significant complications.10 Ilioinguinal–iliohypogastric nerve block. Block of the ilioinguinal and iliohypogastric nerves provides effective analgesia after inguinal herniotomy and for the groin incision performed for orchidopexy. The block is performed easily by infiltrating local anaesthetic (usually 0.25% bupivacaine 1 mg kg–1) medial to the anterior superior iliac

Young children who have been fasted for a prolonged period of time. Procedures known to be associated with a high incidence of postoperative nausea and vomiting (e.g. strabismus surgery). Procedures associated with an increased risk of perioperative haemorrhage (e.g. adenotonsillectomy).

A balanced salt solution is an appropriate i.v. fluid for most situations. Glucose containing solutions are not required routinely as the incidence of hypoglycaemia associated with day surgery in children is low (less than 1%).82

Analgesic techniques Careful attention to pain control is critical for consistently successful paediatric day-case surgery. Effective analgesia requires a balanced approach using local anaesthesia wherever possible, NSAID and, if required, judicious use of opioids.

Local anaesthesia The use of intraoperative local anaesthesia has several advantages, including decreased general anaesthetic requirements, decreased need for opioids (with concomitant decrease in morbidity) and excellent postoperative analgesia. In the context of day surgery, the chosen local anaesthetic technique should be quick and easy to perform with minimal

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spine immediately beneath the external oblique aponeurosis. If only one injection is made, there is an increased incidence of inadequate pain relief after groin surgery. This is because in 50% of patients the subcostal nerve accompanies the iliohypogastric nerve and contributes to innervation of the inguinal region. Consistently effective block of the whole area is achieved by a second injection directed laterally to contact the inside wall of the ilium and infiltrating local anaesthetic as the needle is withdrawn slowly. Timing of block to ensure successful postoperative analgesia is controversial. One study has demonstrated no difference in postoperative analgesia if the block is administered by the anaesthetist percutaneously before surgery or by the surgeon under direct vision during operation.86 However, with a swift surgeon, block performed during operation may not be fully functional as the child emerges from anaesthesia and so my preference is to perform the block before surgery starts. Two further practical points are worthy of consideration. First, for orchidopexy, ilioinguinal–iliohypogastric block must be combined with local infiltration of the scrotum to provide adequate postoperative analgesia. This is because the inferior part of the scrotum is innervated by the pudendal nerve, and therefore the scrotal incision (performed to facilitate testicular fixation) is not covered by the inguinal block. Second, inadvertent femoral nerve block can occur if the local anaesthetic injection is made too near to the inguinal ligament. This may result in leg weakness with delayed mobility in older children.36 Greater auricular nerve block. Block of this nerve, which innervates most of the pinna, provides excellent analgesia (and decreased vomiting) after otoplasty. The block is performed easily by subcutaneous infiltration of local anaesthetic between the mastoid process and the descending ramus of the mandible.

NSAID and paracetamol Non-steroidal anti-inflammatory drugs (NSAID) are effective in relieving postoperative pain after day surgery. They have several advantages which make them suitable for daycase use, including opioid sparing effects, minimal sedation and lack of emetic side effects. The lower age limit for NSAID use is generally accepted as 1 yr, but some centres use them in children as young as 6 months. In UK practice, diclofenac 1 mg kg–1 orally or rectally, ibuprofen 10 mg kg–1 orally and ketorolac 0.5 mg kg–1 i.v. are the most commonly used agents. In addition, topical diclofenac eye drops commenced during operation provide excellent analgesia after strabismus correction.57 Early administration of NSAID after induction of anaesthesia facilitates optimal postoperative analgesia. Oral NSAID can usefully be given as premedication. If rectal dosing is contemplated it should occur after induction whenever possible, but if administration is considered in the conscious child, consent of parents, and the child if appropriate, should be obtained.29 Controversy surrounds the potential for NSAID to increase postoperative haemorrhage caused by inhibition of platelet function. Some studies have shown an increased incidence of wound haematoma in children given diclofenac,74 but this has not been confirmed elsewhere,40 and the majority of paediatric day-case anaesthetists are happy to use NSAID for body surface surgery. More contentious is NSAID use for adenotonsillectomy, particularly ketorolac.30 A recent comprehensive review of NSAID use recommended that NSAID should be withheld from patients after adenotonsillectomy if there has been increased perioperative blood loss or if there is evidence of reduced platelet function.29 The other major controversy is the use of NSAID for children with asthma. The incidence of asthma has increased enormously in recent years, and withholding NSAID from all of these children would deprive a large section of the paediatric day-case population of effective analgesia. Most asthmatic children are not NSAID-sensitive, as this problem is much more common in adult non-allergic type asthma. (It is estimated that 5–10% of adult asthmatics are NSAIDsensitive.23) It is clear that NSAID should be avoided in children who exhibit the triad of NSAID sensitivity, asthma and nasal polyps, and in those children with documented severe asthma, requiring repeated hospitalization, especially ICU admission.29 For the large numbers of children with less severe disease who are more likely to present for day surgery, careful judgement of the relative risks and benefits of NSAID use is required by experienced personnel. Paracetamol is used widely for day surgery in children. A preoperative oral loading dose of 20 mg kg–1 is appropriate, but higher doses (up to 40 mg kg–1) are needed if the rectal route is chosen because of the poor and erratic absorption of paracetamol through the rectal mucosa.54

Caudal epidural block Caudal block is applicable widely in paediatric day surgery, providing excellent analgesia for most day-case procedures below the umbilicus. The potential for lower limb weakness delaying discharge with caudal block can be minimized using weaker local anaesthetic solutions (e.g. 0.125% bupivacaine).95 Several studies have failed to demonstrate that urinary retention is a significant problem after daycase caudal block.10 21 One of the main drawbacks with single-shot local anaesthetic caudal block is that effective analgesia lasts for only a few hours. Recently, addition of NMDA antagonists and alpha-2 antagonists has been shown to prolong markedly caudal analgesia initiated by local anaesthetics. Thus, clonidine 1–2 µg kg–1 doubles and ketamine 0.5 mg kg–1 quadruples the duration of analgesia.15 These drugs are suitable for day-case practice as their use is not associated with significant cardiorespiratory, sedative or untoward psychological effects.

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Table 4 Risk factors for PONV in children d d

d d d

History of PONV or motion sickness Surgical procedure e.g. strabismus correction, adenotonsillectomy, prominent ear correction, orchidopexy Opioids, especially morphine Early postoperative mobilization Early postoperative oral fluids

d

d d d d d d d d d

Opioids The routine use of long-acting opioids for day surgery in children is inadvisable as it is associated with excessive morbidity, notably excessive sedation and postoperative vomiting. Indeed, if an operative procedure is consistently found to necessitate postoperative opioid analgesia, then it is probably not suitable as a day-case procedure. However, for some day-case children, single doses of opioids can be useful to achieve rapid pain control in the immediate postoperative period if NSAID and local anaesthetic techniques are inadequate. Fentanyl (up to 2 µg kg–1) i.v. or codeine 1 mg kg–1 orally, rectally or very rarely, i.m., are useful in this respect.

Vital signs and conscious level normal for age and preoperative condition of child Protective airway reflexes fully regained No respiratory distress or stridor No unexpected intraoperative anaesthetic events No bleeding or surgical complications PONV absent or mild Pain absent or mild Appropriate ambulation for age of child Written/verbal instructions issued and lines of contact emphasized Escort home by responsible adult in private car or taxi

low dose does not decrease the incidence of vomiting after strabismus correction.24 More recently, 5-HT3 antagonists have become established in paediatric day-case practice. Both ondansetron and granisetron have been shown to be effective in preventing PONV.24 65 The main advantages of this group of drugs are the lack of sedative and extrapyramidal effects, but their use may be limited by cost.24

Postoperative management Recovery

Postoperative nausea and vomiting Postoperative nausea and vomiting (PONV) are major issues in paediatric day surgery. In a series of 15 000 children’s day cases from a leading North American centre, PONV were the commonest causes of unexpected inpatient admission.63 Unfortunately, many of the commonly performed day-case procedures are associated with a high incidence of PONV (e.g. adenotonsillectomy has a 70% incidence,26 prominent ear correction 60%70 and strabismus surgery as high as 80%).1 Recognizing the child at risk of PONV is essential to managing this difficult problem (Table 4). A range of measures can then be targeted at these children to minimize the incidence of PONV. General strategies include avoiding excessive preoperative fasting, maintaining good perioperative hydration, discouraging early postoperative oral intake and avoiding rapid mobilization in the recovery period.3 As far as the anaesthetic technique is concerned, emetic agents (particularly opioids) should be avoided. The role of nitrous oxide is controversial, with some studies reporting an increased incidence of PONV94 and others reporting no increased emetic problems.61 Total i.v. anaesthesia with propofol has been reported to be associated with low PONV rates for high-risk procedures, such as strabismus surgery.90 Routine antiemetic prophylaxis is not required for all paediatric day patients but should be used for all high-risk cases. Many traditional antiemetics have proved disappointing in day-case practice either because of low efficacy or unacceptable side effects, such as excessive sedation or extrapyramidal reactions.3 Droperidol has proved useful in low dosage (20 µg kg–1) to decrease PONV in day-case patients without adverse effects,45 but such a

After day surgery, children should recover in a fully equipped recovery room by staff experienced in the management of unconscious paediatric patients. Although timing the transfer of a child from the first stage recovery room is usually decided intuitively, some day units use the Steward score to objectively assess the return of protective reflexes. Wakefulness, movement and airway control are assessed and assigned a score of 0, 1 and 2.80

Discharge criteria Deciding the appropriate time to discharge the child home after day surgery depends on anaesthetic, surgical and social factors, and the adequacy of postoperative symptom control (Table 5). Although tracheal intubation does not preclude discharge, day unit staff must watch carefully for signs of post-extubation stridor, particularly in children less than 5 yr of age. Some units recommend that all children who have been intubated should stay a minimum of 2 h before discharge.63 Continuing lower limb motor block after caudal block (or occasionally inguinal block) does not preclude discharge in the infant or toddler age group, but can delay return home for older children. The ability to tolerate oral fluids is a common criteria for discharge from day surgery. However, several studies testify to the safety of allowing children to be discharged home without drinking, provided they have received perioperative i.v. hydration and met other discharge criteria.39 78 There were no readmissions in either study for dehydration, and vomiting rates were significantly reduced by this approach. Similarly, many day units require children to pass urine before discharge home, particularly if they have received a

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Table 6 Oral analgesia regimen after discharge home

Reasons for inpatient admission

Paracetamol 15 mg kg–1 6 hourly Paracetamol 15 mg kg–1 6 hourly 6 ibuprofen 10 mg kg–1 6 hourly or codeine elixir 0.5 mg kg–1 6 hourly Older children (.10 yr) Compound paracetamol/codeine preparations, e.g. cocodamol, 6 ibuprofen 200–400 mg kg–1 6 hourly

Occasionally, unexpected complications necessitate hospital admission of children after day surgery. The possibility of inpatient admission should always be discussed with parents before operation so that the potential for family disruption is minimized. A widely quoted benchmark figure for inpatient admission is 1–2% of the day unit’s caseload, although a leading North American unit reports a rate of only 0.3%.64 Both surgical and anaesthetic complications result in the need for inpatient admission but the commonest problems are vomiting and severe pain. Post-extubation stridor is a significant cause for admission in North American practice, but is uncommon in the UK because of the increased use of the laryngeal mask for airway management.

Infants (,1 yr old) Children .1 yr

caudal block. However, in a study comparing caudal and inguinal blocks in day surgery, urinary voiding intervals were identical, with no cases of urinary retention in either group.21 Thus on anaesthetic grounds it is reasonable to discharge children who have not passed urine, but surgical indications for insisting on this rule (e.g. penile surgery) should be respected. Before the child is discharged, it is vital that parents receive clear verbal and written instructions about the child’s aftercare, particularly with regard to analgesia, diet and resumption of normal activities, such as return to school. Telephone contact numbers should be included where parents can seek advice and report complications, as appropriate. Many units telephone all families the day after surgery to provide reassurance to parents and give advice as appropriate. This telephone call also fulfils an important audit function, allowing data to be collected regarding postoperative pain, vomiting and surgical morbidity.56

Postoperative pain control Children should not be discharged after day surgery until pain is well controlled and staff are confident that oral medication will provide adequate analgesia at home. Severe postoperative pain should not be a major problem after day surgery provided that local anaesthesia and NSAID have been used as part of the anaesthetic technique, and the operative procedure is one that is not associated with severe postoperative pain. In Cambridge, 10% of children experience mild or moderate pain, and only 1% severe pain when in the day unit.68 An appropriate pain assessment tool is essential to provide optimal analgesia. Numerous pain scoring systems are available for paediatric use, each with their own advantages and disadvantages,56 but whichever system is used, assessment should be repeated regularly in response to analgesic interventions. Although the mainstay of pain relief after return home is oral analgesia (Table 6), topical preparations, such as lidocaine gel after circumcision and diclofenac drops after strabismus surgery, are very effective. The importance of educating parents to give postoperative analgesia on a regular pre-emptive basis rather than waiting for a child to become excessively uncomfortable, cannot be overemphasized.5 One recent study has shown that after tonsillectomy, 18% of children who complained of significant pain failed to receive any analgesics.71 Depending on the procedure, it is therefore important that analgesics are prescribed on a scheduled basis for up to 3 days after operation.

Conclusion Day-case management is beneficial for children, their families and the providers of health care. Modern anaesthetic techniques which aim to minimize postoperative morbidity are essential to successfully delivering this mode of care.

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