Paediatric day-case surgery is growing in popularity because of lower cost, less risk of infection and minimal separation from parents . This expansion should not be at the cost of substandard quality of care and requires a thorough understanding of the associated risks. Unplanned hospital admission represents a measure of outcome and quality of care .
Factors found to be associated with unplanned admission include pain, emesis, male gender, long duration of surgery, and ear, nose and throat surgery [3,4]. However, these results were observed in adult only or mixed population studies and do not necessarily represent those seen in children . Previous studies have examined the outcome following paediatric day-case surgery, but were limited by study size or by using patients undergoing specific group(s) of surgical procedures [6-8]. Due to the advances in anaesthetic and surgical techniques, together with ever-increasing healthcare costs, more complex and difficult surgical procedures are being performed on a day-case basis . In the interests of efficiency, patient safety and parental satisfaction it is important that we are aware of the factors that increase the likelihood of unplanned admission. The objective of this study was to identify the incidence and causes of unplanned hospital admission following paediatric day-case surgery.
A retrospective survey was undertaken for children who had required unplanned hospital admission following day-case surgery between 1 January 1996 and 31 December 1999 in our hospital, The Children's University Hospital in Dublin, which is a tertiary referral teaching hospital. Unplanned hospital admission was defined as any admission from the day ward to an inpatient ward after 17:00 h (the official closing time for the day ward) with an overnight stay. Any patient admitted to an inpatient ward who was discharged home later on the same day was defined as a patient with unplanned hospital admission and delayed discharge.
Patients admitted to the hospital wards from the day surgical wards were identified from the day ward admission book and the hospital computerized database. The medical records of the identified patients were subsequently retrieved and examined thoroughly by the investigators. The following information was documented on a structured datasheet modified from a previous study on an adult population : patient characteristics, ASA Grade, anaesthetic technique, category of surgery, time of completion of surgery, time of discharge from the recovery room and post-operative complications. Time of completion of surgery was divided into three periods: 08:00-11:59 h, 12:00-14:59 h and later than 15:00 h.
Reasons for admission were classified into five groups: surgical, anaesthetic, social, medical and unclassified. Surgical reasons included pain, bleeding, extensive surgery, surgical complications and/or further management and observation. Anaesthetic reasons included postoperative nausea and vomiting (PONV), anaesthesia-related complications and delayed awakening. Social reasons for admission were late surgery, parents' request, long distance from home and 'social unsuitability'. Medical reasons included pre-existing medical problems, undiagnosed medical disease and medical complications. Reasons were unclassified, when no other reason was documented. Data were documented on a structured data sheet and subsequently entered into a computerized database. The responsible medical team was consulted to obtain clarification of any admission where the reason for admission was unclear. It was possible to assign multiple reasons to one admission.
Of the 10 772 children treated in our ambulatory surgical unit during the study period, 242 (2.2%) patients were admitted to an inpatient ward. The median weight of those admitted was 17.5 kg (range 3.3-70 kg). The ages ranged from 2 weeks to 16 yr with a male to female ratio of 2.3:1 (Table 1). The median fasting time was 12 h (range 3-35 h). Surgical procedures performed in the morning between 08:00 and 11:59 h were associated with a high incidence of unplanned hospital admission. The duration of surgical procedures was less than 60 min in 73%, between 60 and 120 min in 23% and more than 120 min in 4% of cases. As a percentage of caseload, genitourinary surgery was associated with the highest incidence of unplanned hospital admission followed by ophthalmology, orthopaedic surgery, general surgery, plastic surgery and others (Table 2).
Out of a total of 269 reasons for unplanned admission in 242 patients, surgical causes accounted for 146 (54%), anaesthetic 44 (16%), social 38 (14%), medical 31 (12%) and unclassified 10 (4%) (Table 3). Orthopaedic surgery accounted for the largest absolute number of admissions with 61 (25% of total), followed by general surgery 46 (19%), urology 46 (19%), ophthalmic 34 (14%), plastic surgery 32 (13%), ear, nose and throat 21 (9%), and dental surgery 2 (0.8%). Orchidopexy, performed alone or together with other procedures, accounted for 34% of admissions for pain management (Table 4). Fifteen patients were admitted to the hospital and later discharged.
Admissions because of anaesthesia-related complications were due to desaturation during the recovery period in six patients necessitating postoperative oxygen therapy, two patients admitted for observation for the possibility of malignant hyperpyrexia, two patients for treatment of postoperative bronchospasm and one patient was admitted because of multiple unsuccessful attempts at intubation with the potential of subsequent airway oedema.
The main finding of our study is that surgical and anaesthetic factors were the major reasons for admission following paediatric ambulatory surgery. The incidence of unplanned hospital admission of 2.2% in our study is low considering the fact that the Children's University Hospital, Temple Street is the second major referral centre for paediatric surgery in Ireland, and that a wide variety of complicated procedures are conducted in its theatres. Admission rate is slightly higher in hospitals undergoing day-case tonsillectomies because of bleeding complications. The incidence of unplanned admission in adults is quite variable and ranges from 0.28% to 9.5% . This variability is attributed to case selection, complexity of procedures and to local institutional protocols and policies.
Pain was the main surgical reason for admission, which confirms previous findings in adults . Surgeons can play a significant role in reducing the severity of postoperative pain through the use of small incisions, wound infiltration with local anaesthetics and the implementation of minimal invasive surgery [10-13]. Orchidopexy is not a straightforward procedure and can involve much dissection and tissue handling. Studies have shown favourable outcomes with minimal invasive surgery using two-stage surgery where accurate identification of a testis can reduce the pain and morbidity of an extensive groin exploration [14,15]. Our findings tend to confirm those of a recent study, which found that children undergoing orchidopexy require significant amounts of analgesic medication after discharge from day-case surgery .
In other studies, nausea and vomiting were the most common causes of unanticipated hospital admission following ambulatory surgery  but they accounted for only 8% of the causes in our survey. The opioids used in our operating theatres are mainly fentanyl or Cyclimorph® (Wellcome Ireland Ltd., Clonskeagh, Dublin 4, Ireland). The latter is a combination of morphine 10 mg and cyclizine 50 mg in 1 mL ampoules. Cyclimorph® is used on a wider scale than fentanyl and therefore patients are benefiting from an antiemetic drug given with each bolus dose of morphine. The problem of nausea and vomiting is probably attributed to the long fasting times we noticed in this study. The risk of aspiration in infants and children is very low in elective surgical procedures compared with emergency surgery . Fasting times for clear fluids should be 2 and 5-6 h for solids and milk [19,20]. Timing when to give clear fluids prior to surgery depends largely on the coordination between the day surgical ward and operating rooms.
Other factors that could influence the incidence of PONV are the type of surgery, perioperative use of opioids and the compulsory postoperative oral intake prior to discharge. Provided patients are given adequate amounts of fluids in the operating room, there is no need to force patients to drink prior to discharge. In children, mandatory drinkers experienced more episodes of vomiting and stayed longer in the day surgical ward . Conversely, in the adult population there is no difference between mandatory drinkers and elective drinkers with regard to incidence of vomiting, duration of stay in hospital and unplanned hospital admission .
Of the 242 children admitted, 27 were trauma patients who were initially admitted to the day ward because of shortage of inpatient beds in the hospital. This may have led to an artificial increase in the number of orthopaedic admission. Admissions for social reasons were mainly due to surgery performed after 15:00 h. It is quite clear that operations performed late in the day carry a high risk of admission, as there is limited time to ensure adequate recovery. It would seem more reasonable to extend the opening hours of the day wards.
Medical causes of unplanned admission were mainly due to preoperative medical disease. Proper selection and adherence to strict criteria of suitability for day-case surgery would make this possibility a rarity.
The main weaknesses of our survey are the fact that it was retrospective and that information may have been missed or inaccurate. We relied on the anaesthetic and nursing notes which in the majority of cases provided adequate documentation of the factors associated with unplanned admissions. Secondly, the results were not directly compared against those of a control group of patients who were discharged safely home. This approach would have enabled us to determine risk factors through logistic regression analysis. In conclusion, this study demonstrates that the causes of unplanned hospital admission in children were similar to those in adults. Pain, nausea and vomiting remain a big problem. A multimodal approach to pain relief using a combination of opioids, non-steroidal anti-inflammatory drugs and regional techniques would accelerate postoperative recovery and reduce the number of overnight admissions due to pain [23,24].
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