Unanticipated Admission After
C Tham, K F Koh
5 Lower Kent
C Tham, MBBS,
K F Koh, MBBS,
Dr C Tham
Tel: (65) 6772 4207
Fax: (65) 6777 5702
Day surgery is becoming more common due to its
cost effectiveness as well as patient acceptance.
With increasing caseloads, there is a need to
maintain quality of care. The purpose of this study
is to identify the reasons for unanticipated
admissions in our day surgical population, with
the aim of improving efficiency of day surgical
services, yet maintaining a high standard of
patient care. A retrospective review of records of
patients who were admitted over the two-year study
period was conducted. Unanticipated admission
was defined as unplanned admission after a
day surgical procedure. Data relating to physical
status, perioperative complications and reasons
for hospital admission were recorded. A total of
10,801 procedures were done, and 163 patients
were admitted. The unanticipated admission rate
was 1.5%. Most of the admissions were surgically
related (62.8%), followed by anaesthesia (12.2%),
social (9.5%) and medical reasons (8.1%). Seventy-
five percent of these admissions were potentially
preventable. The majority were due to common
problems like postoperative pain, admission for
surgical observation and for social reasons.
Non preventable causes (25%) were mainly due
to unrelated medical problems.
Keywords: day surgery, admissions, perioperative,
Singapore Med J 2002 Vol 43(10):522-526
Day surgery is a modern and cost effective method
to treat surgical patients. In many countries, this
accounts for greater than 50% of the surgical load.
However, apart from reducing health care cost, there
is also a need to maintain quality care. Defining this
quality is difficult. Unanticipated admission after day
surgery can be a good indicator as it concerns the
basic goals of same day discharge.
The incidence of unanticipated admission varies
from 0.3-9.5%(1-3). In many series, the main reasons for
admission were surgical (38-58%), followed by
anaesthesia related (25-37%), medical (17%) and social
reasons (4.6-19.5%). The purpose of our study was to
audit the quality of patient care using unanticipated
admissions as a criterion. We aim to improve the overall
efficiency of ambulatory services by analysing the
reasons for admission, providing solutions to avoid
preventable causes of overnight admission.
Our day surgery unit consists of a day surgery ward,
an admission area, five operating theatres and a
six-bedded recovery room. The unit is separate from
the main operating theatres but is within the hospital
complex. The surgical disciplines using the day surgical
centre include general surgery, urology, orthopaedics,
gynaecology, ENT and ophthalmology. Our standard
patient selection criteria for day cases include those of
ASA I to III status between six months to 70 years old,
undergoing procedures lasting less than 90 minutes
that were not expected to cause excessive fluid shift
or physiological impairment postoperatively.
We retrospectively collected data of patients who
were admitted after day surgery procedures for a two-
year period from September 1996 to August 1998.
The list was obtained from the day surgery centre
register. The medical records of these patients were then
reviewed to determine their physical status, perioperative
complications and the main reason for hospital
admission. Unanticipated admission was defined as
unplanned admission after a day surgery procedure. The
admitting doctor can be the surgeon or the anaesthetist.
Prior to their listing all patients were screened using
a questionnaire. Patients, who were classified as ASA
II and III status were reviewed by an anaesthetist
before they were scheduled for operations. Those
deemed unfit for day surgery procedures would
have their operations done as inpatient and were not
included in our study.
The patients were discharged by the surgical staff
using Korttila’s criteria i.e. stable haemodynamics,
minimal pain, nausea, vomiting or bleeding, able to
drink, void and walk unaided and must be discharged
Singapore Med J 2002 Vol 43(10) : 522-526
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Singapore Med J 2002 Vol 43(10) : 523
to the care of a responsible adult(4). Those who are
unable to fulfil the criteria were admitted to hospital.
As a rule, no general anaesthesia was administered
after 1500 hours to allow patients ample time to
recover from the effects of anaesthesia prior to close
of the day surgery centre.
During the period of study, there were a total of
10,801 procedures done in the day surgery centre.
Of these, 163 patients were admitted. Fifteen patient
records were unavailable and were thus excluded from
further analysis. The majority of patients admitted were
in the 20-39 years age group. This was mainly due to the
large proportion of this age group presenting for day
surgery. The physical status of the patients admitted
(ASA I: 109/148, II: 34/148, III: 5/148) was comparable
to that of our general day surgical population. The
distribution of surgical procedures and admission
rates according to specialties is shown in Table I.
The unanticipated admission rate was 1.5%. Among
the reasons for admission, 75% were potentially
preventable. These were mainly admissions for control
of postoperative pain, surgical observation and social
reasons. Knee arthroscopies (8/27), breast augmentation
(7/27) and laparoscopic gynaecological procedures
(5/27) were those that caused significant postoperative
pain. Nineteen of the 47 that were admitted for surgical
observation were ENT patients for observation for
bleed and management of nasal pack. The others in
this group, were contributed mainly by gynaecology
patients (16/47). There were smaller contributions
from general surgery (6/47), followed by plastics (3/47),
urology (1/47), and ophthalmology (2/47). Of those
admitted for social reasons, 13 were on request from
either patient or relatives, and only one was admitted
because of lack of suitable escort to take him home. All
seven patients who had more extensive surgery than
planned were gynaecology patients who after initial
laparoscopic assessment, had to undergo laparotomy
due to extensive surgical pathology not amenable to
Non-life threatening morbidity like delayed
recovery, nausea and vomiting contributed to the
majority of preventable anaesthetic related admissions.
Of the patients who had slow recovery, one had
undergone cataract surgery under sedation in the late
afternoon. He had failed to satisfy the discharge criteria
and had to be admitted when the centre closed. One
other patient had prolonged recovery but no specific
reason was found. The remaining four in this group
complained of severe giddiness upon reversal from
general anaesthesia and therefore had to be admitted.
Four patients had perioperative airway problems that
necessitated admission; two patients aspirated during
induction, one desaturated due to laryngospasm and
the last had non cardiogenic pulmonary edema.
Only a quarter of total admissions were due to non-
preventable causes like drug reaction, difficult airway,
surgical bleed or other direct surgical complication
and unrelated medical conditions. Two patients were
suspected of developing allergy to antibiotic eyedrops
after cataract surgery. Out of the nine direct surgical
complications, four patients had visceral perforation
during laparoscopy, one was suspected of air embolism,
one experienced haematuria after urethroscopy. Two
patients had complications during cataract surgery;
one had anterior chamber rupture, another hyphema
postop. There was also a case of bile leak after a liver
biopsy. The three patients who had difficult airway
were ENT patients who had undergone direct
laryngoscopic examination; they had copious secretions
post examination and were admitted as a precaution.
Twelve patients were admitted for medical reasons
like postoperative angina arrhythmias, hypertension and
bronchospasm. Of the five patients who required further
investigation or treatment, two were for radiotherapy
or hematologist referral, another two were admitted
for cardiac workup because of abnormal ECGs and
one for intravenous antibiotics therapy.
Annually, more than 50% of operative procedures
done in our hospital were performed on an ambulatory
basis. With increasing efforts to control health care
expenditure and improved anaesthetic and surgical
techniques, patients with complex medical conditions
Table I. Unanticipated Day Surgery Admission.
Specialty No. of Cases
(% of total)
No. of admissions
(% of patients admitted
under each specialty)
Dental 179 (1.6)1 (0.6)
ENT 771 (7.1)19 (2.5)
Ophthalmology1695 (15.7)36 (2.1)
Gynaecology2115 (19.6) 37 (1.75)
Paediatric surgery787 (7.3)11 (1.4)
Urology640 (5.9) 6 (0.94)
Plastics1048 (9.7) 10 (1.0)
General Surgery1411 (13.1)12 (0.9)’
Orthopaedics1005 (9.3)16 (1.6)
Hand surgery1150 (10.6)0
(Total no. of cases done)(Total no. of admissions)
524 : 2002 Vol 43(10) Singapore Med J
undergoing complicated procedures will be done in
day surgery. While it is important to monitor the
quality of patient care by monitoring admission rate,
it is also essential to audit the reasons for admission
so that potentially preventable causes of admissions
can be avoided, thus improving the overall efficiency
of ambulatory services.
Our unanticipated admission rate was 1.5%.
This compares favourably to other studies(1,2) but may
be higher than those done at free-standing ambulatory
centres. The hospital based setup of our ambulatory
unit allowed surgeons to perform more extensive
surgery after initial diagnostic procedures, as the
patients could be admitted for further management
postoperatively. At freestanding centres, the operation
would not proceed and the patient would be rescheduled
for further surgery as an inpatient.
From our study, most of the reasons for
unanticipated admissions were due to non-life
threatening causes, 75% of which were potentially
preventable. These were mainly admissions for
observation for bleeding, pain management (50%
of total admissions) and for social reasons. Most
admissions for bleeding were ENT patients. The
discipline also had the highest admission rate (2.5%).
Common ENT procedures performed in our centre
include nasal surgery like septoplasty, endoscopic
sinus surgery, tonsillectomies and adenoidectomies.
The possibility of compromising the airway from
contamination or obstruction makes it more likely
for surgeons to admit these patients. Fortier and
Chung also found that ENT patients had the highest
admission rates (18.2%)(6). In a separate study in an
ENT day surgery unit, it was found that the majority
of admissions were after nasal surgery. The rate was
13.4% for patients undergoing septoplasty, mainly
due to bleeding(7). Observation for bleeding following
termination of pregnancy and monitoring for surgical
complications after laparoscopic hydrotubation were
main reasons why gynaecology patients were admitted
for observation. To help reduce admissions, gynaecology
patients undergoing these procedures and ENT patients
having nasal surgery should be scheduled in the
earlier part of the day. They can be observed for
bleeding and surgical complications over a longer
period, thus avoiding “over cautious” admissions.
ENT patients requiring longer and more extensive
nasal surgery should be managed as inpatients.
Investigators have demonstrated that surgical time
longer than 60 minutes is an independent predictor
of unanticipated admission(8).
Adequate pain management remains a challenge
in day surgery. Patients must be comfortable before
discharge, yet free from side effects of most narcotics.
Combination of infiltration with local anaesthetics
or regional anaesthesia with an NSAID is usually
sufficient for the range of cases done in day surgery.
Failures are known particularly in cases like knee
arthroscopy, breast augmentation and laparoscopic
surgery, as seen in our study. Multimodal pre-emptive
approach to pain management, together with use
of newer non narcotics (ketorolac, tramadol) and
novel use of local anaesthetics (intraperitoneal(10),
intraarticular or paravertebral) can contribute to good
pain control and reduce the need to admit patients for
parenteral analgesics. A change in traditional surgical
technique may help reduce postoperative pain e.g.
use of CO2 laser during tonsillectomy(11). A commonly
neglected area is patient education. Patients often
have unrealistic expectations of postop pain relief.
They do not know when to take oral analgesics to
maximise its effects or use simple physical measures
like cold compress to alleviate pain. Up to 50% of
patients have reported that instructions in pain
control were unclear(12).
Common perioperative anaesthetic related
morbidity like giddiness and PONV can also be
reduced. The most common cause for drowsinesss
and giddiness is poor hydration. Yogendran et al found
that outpatients who received 20 versus 2 ml/kg of
intravenous hydration had less giddiness, nausea and
vomiting postop(13). Patients who had been fasted for
Table II. Reason for admission.
(A) Surgical related
More extensive surgery than planned
(B) Anaesthesia related
Nausea and vomiting
(A) Surgical related
Other direct surgical complication
(B) Anaesthesia related
Acute retention of urine
Unrelated medical problems
Total no. of admissions 148
long periods (>10 hours) having procedures lasting
more than two hours should have adequate intravenous
Elderly patients are more susceptible to prolong
recovery with slower return of cognitive function. They
should have their procedures done in the earlier part of
the day to allow adequate time for recovery from general
anaesthesia. For those who require sedation for their
procedures, judicious use of appropriate sedatives
would reduce recovery time.
The new serotonin antagonist, ondansetron has
been effective in treatment of established postoperative
emesis(14). Routine use of prophylactic antiemetics in
susceptible patients who have previous history of
postop vomiting and for those with significant risk
factors for PONV (e.g. history of motion sickness,
laparoscopic surgery, middle ear surgery), can prevent
unnecessary delay in discharge or unanticipated
admission. Simple measures like ensuring adequate
hydration can contribute to reducing PONV and
The incidence of aspiration in the general surgical
population ranges from 1 in 2,000 to 1 in 14,000
general anaesthetics(14,15). In our study, the two patients
who aspirated had fulfilled our day surgery fasting
guidelines and had no risk factors for aspiration (2 in
10,801). They had reacted to laryngeal mask insertion
during induction and had aspirated on regurgitated
gastric contents. Such problems could be avoided if
adequate depth of anaesthesia was achieved before
airway manipulation or surgical stimulus.
Social conditions should be carefully assessed
preoperatively. It is important to explain to the family
the support needed for successful outcome from
day surgery. Proper explanation of the availability of
medical support should problems occur would help
allay fears and reduce requests for social admission.
Despite careful patient selection and change in
day surgical practice, there will always be a small
percentage of admissions that are unavoidable. In our
study, a quarter of our admissions were unpreventable.
These were mainly contributed by unrelated medical
conditions (8%) and direct surgical complications
(6.1%). Fifty percent of those with medical conditions
were elderly outpatients for cataract surgery. While
the preoperative questionnaire is a helpful screening
tool, careful assessment at the preanaesthetic clinic
prior to the operation may be necessary to identify
those with uncontrolled medical conditions who are
unfit for day surgery.
Airway problems are always a concern for the
anaesthetists. Patients with potentially difficult airway,
(e.g. carcinoma of larynx for direct laryngoscopic
assessment) or those with altered anatomy as a result
of previous treatment, (e.g. limited neck movement
or mouth opening post radiotherapy) should be
scheduled as inpatients as they are at higher risks of
Factors predisposing to complications after
ambulatory surgery are operative time >3 hours,
general anaesthesia, preexisting cardiovascular
disease, hypertension, chronic pulmonary disease and
asthma(16). These should be considered during patient
selection. Other predictive factors for unanticipated
admissions include male gender, surgery finishing
after 1500 hours, postop bleeding, excessive pain,
nausea, vomiting, drowsiness and dizziness(6). Some
admissions can be avoided by careful scheduling. This
should take into account the complexity, duration of
surgery and expected recovery period. The later slots
of the day should be reserved for shorter procedures
and those with least potential for complications
In our study, we noted that a major proportion
of unanticipated admissions were due to non-life
threatening causes which were potentially preventable.
Despite careful patient selection, there will always
be a small contribution from unrelated medical
causes or direct surgical complications. It is essential
to monitor admission rates in order to maintain a high
quality of patient care in this era of cost containment.
The authors wish to thank Dr W H Wong, Associate
Consultant, NUH, for his help in the preparation
of the manuscript for publication.
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