The effect of increasing operating room capacity on day-of-surgery cancellation.
Abstract: Several studies have been conducted to evaluate the utilisation of the operating room, a fixed resource, in terms of conditions that prevent day-of-surgery cancellation due to deficient operative capacity. In this study, we surveyed the causes and overall rates of elective surgery cancellation and then compared the number of cancellations that occurred before and after the installation of additional operating rooms.

We surveyed all patients undergoing elective surgery for 100 days prior to and after the installation of additional operating rooms. The causes for cancellations were divided into six categories: departmental issues, abnormal laboratory results, patient denial, inadequate preparation, over-booking and other issues. The departmental causes were further divided into four categories: ward overflow, scheduling date errors, unavailable surgeons and other issues.

The number of overall cancelled cases and scheduled cases increased following the increase in operating room capacity, although this increase was not statistically significant. However, the cancellation ratio rose significantly after the operating room capacity was increased. The primary reasons for cancellation prior to the increase in operating room capacity were departmental issues, over-booking and abnormal laboratory data, in that order. After the operating room capacity was increased, the primary reasons for cancellation were departmental issues, abnormal laboratory data and over-booking, in that order. Taken together, the results of this study indicate that increased operating room capacity can prevent cancellation due to over-booking. However, the numbers of cancellations due to ward overflow exceeded the numbers of cancellations that occurred as a result of over-booking.

In conclusion, increasing the operating room capacity is not an appropriate option for preventing the cancellation of operations.

Key Words: anaesthesia, cancellation, costs, operating room
Article Type: Report
Subject: Medical errors (Causes of)
Medical errors (Prevention)
Operating rooms (Capacity)
Medical care, Cost of (Management)
Authors: Yoon, S.-Z.
Lee, S.I.
Lee, H.W.
Lim, H.J.
Yoon, S.M.
Chang, S.H.
Pub Date: 03/01/2009
Publication: Name: Anaesthesia and Intensive Care Publisher: Australian Society of Anaesthetists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Australian Society of Anaesthetists ISSN: 0310-057X
Issue: Date: March, 2009 Source Volume: 37 Source Issue: 2
Topic: Event Code: 445 Capacity; 200 Management dynamics Computer Subject: Company business management
Geographic: Geographic Scope: South Korea Geographic Code: 9SOUT South Korea
Accession Number: 197857878
Full Text: Case cancellations may lead to patient dissatisfaction and can be quite costly. In addition, the cancellation of an operation may be stressful and costly to patients in terms of lost working days and disruption of their daily life. Furthermore, it has been reported that the cancellation of an operation causes depression in patients as a result of the high level of emotional involvement associated with surgery (1). Concerning the cost of cancellation of operation, for non-US hospitals and US hospitals with a fixed annual budget, cancelling a case and performing it on another day increases costs to the physicians, hospital, patient and society, even if overtime would have been required to perform the case on the originally scheduled day (2).

The reported rates of day-of-surgery cancellation vary widely among institutions, partially as a result of differences in the definition of operating room (OR) cancellations and the method by which cancellation data are collected. However, it has been reported that day-of-surgery cancellation rates range from 13 to 23.8% (3-5). The most common cause of cancellation is patient medical problems, followed by deficient operative capacity. Therefore, many studies have been conducted to identify methods for preventing the cancellation of operations due to patient medical conditions. Additionally, various studies have shown that the number of cancelled operations decreased and the number of same-day admissions increased following the implementation of an out-patient preoperative evaluation clinic (6-8). A number of studies concerning the scheduling strategy have evaluated the utilisation of the operating rooms with a fixed resource (e.g. block time), in terms of conditions that prevent day-of-surgery cancellation which were due to deficient operative capacity (9,10).

However, to date no studies have been conducted to evaluate the effects of installing additional ORs on day-of-surgery cancellations. Therefore, in this study we investigated the causes and overall rates of elective surgery cancellation before and after the installation of additional ORs and evaluated the data that was generated to determine if increased operative capacity can prevent day-of-surgery cancellation.


Characteristics of the institution

The institution evaluated in this study was a 600-bed university hospital with ten operating rooms, seven board-certified anaesthesiologists, nine resident anaesthesiologists and 15 anaesthesia physical assistants (mostly registered nurses). The post-anaesthesia care unit was staffed by three anaesthesia physical assistants and one resident anaesthesiologist. The institute used a "Fixed Hour System" for OR allocation. Therefore, there was a nine-hour block of time from 0830 to 1730 hours during which operations could be conducted.


The study protocol was reviewed by the Institutional Review Board and approved as a minimal risk study that did not require individual consent based on the institutional guidelines for waiving consent. The institution evaluated here does not contain an out-patient surgery centre or an out-patient preoperative evaluation clinic; therefore, approximately 90% of the patients who were scheduled to undergo elective surgery requiring general anaesthesia were admitted at least one day prior to their operation and stayed in the hospital for at least one night or more following surgery. The remaining 10% were discharged from the hospital on the same day as the operation, regardless of whether they were admitted on the same day or not. These cases were considered to have undergone out-patient anaesthesia, which was most commonly comprised of sedation/monitoring, followed by intravenous general anaesthesia. We excluded from this survey, patients who underwent out-patient anaesthesia, emergency surgery or operations performed on holidays and weekends.

The administrative department believed there would be a substantial overall institutional financial gain as a result of improved throughput in the OR if it resulted in an increase in the reimbursable surgical volume. Accordingly, they added two ORs to the operating theatre without increasing the number of staff members. The new ORs were constructed from October through November, 2003. We therefore surveyed all patients scheduled to undergo elective surgery requiring general anaesthesia for 100 days beginning on July 1, 2003 prior to the installation of the additional operating rooms. To avoid seasonal or monthly variations, as well as other factors that may affect cancellation rates and settling-in period of new ORs, the after-survey was conducted for 100 days beginning July 1, 2004.

Preoperative evaluation

The anaesthesiologist visited each patient in the ward the day before surgery. The patient's medical history was then obtained and a physical examination was conducted, after which the patient was informed about anaesthesia. All patients in the ward had a predetermined set of laboratory results from tests that were performed by the surgical out-patient department prior to surgery. The results included electrocardiograms, chest X-rays, liver function tests, complete blood count, blood urea nitrogen, creatinine and serum electrolyte concentrations, a urine analysis and viral markers for hepatitis. The anaesthesiologist also evaluated the laboratory results.


The causes of cancellation were divided into six categories that were determined based on previously conducted studies (3-5,11). These categories included departmental issues, patient medical problems, patient denial, inadequate preparation, over-booking and other issues. The operating room clerical staff documented the reasons for cancellation prospectively at 1630 hours, one hour before the end of the nine-hour time block.

The departmental issues were further divided into four categories: ward overflow, scheduling date error, unavailable surgeon and other issues. A ward overflow was defined as the patient being denied admission due to a lack of beds in the general ward. Scheduling date errors were defined as patients being told to report for surgery on the wrong day. Patient medical problems were defined as the need for additional preoperative laboratory tests or clinical consultations prior to surgery, or as the occurrence of an upper respiratory tract infection prior to surgery. Patient denial was defined as the patient choosing not to undergo the procedure. Inadequate preparation was defined as the need for additional preoperative work-up and extra preoperative preparations such as bowel preparation, as well as cancellation due to the patient disregarding preoperative instructions, such as the nil per os rule. Cancellation due to over-booking was defined as an inability to begin surgery due to missing the nine-hour time block.

Statistical analysis

To determine if the examined parameters differed significantly before and after the installation of two additional operating rooms, the differences in the means of all parameters evaluated in this study were compared using a chi-square test. A P value of <0.05 was considered to be statistically significant.


During the 100 days evaluated prior to the installation of two additional operating rooms, 2494 patients were scheduled for elective surgery. Of these 2494 patients, 512 had their operations cancelled, which gave an overall cancellation ratio (cancelled cases/scheduled cases) of 20.5%. Following the installation of additional ORs, 2886 patients were scheduled for elective surgery over a period of 100 days. Among these 2886 patients, 688 had their operations cancelled, which gave an overall cancellation ratio (cancelled cases/scheduled cases) of 23.8%. There were no statistical differences in the number of scheduled cases and cancelled cases. However, there was a statistical difference in the cancellation ratio (Figure 1).



Prior to the increase in OR capacity, the most common reason for cancellation was over-booking (157), followed by departmental issues (144) and patient medical problems (127). Following the increase in OR capacity, the most common reason for cancellation was departmental issues (365), followed by patient medical problems (174) and over-booking (54) (Figure 2).

When the reasons for cancelled elective operations were compared between the two periods (Figure 2), departmental issues, patient denial and over-booking differed significantly. No other reasons for cancellation differed significantly between the two groups.


The most common departmental reason for cancellation in both periods was ward overflow (Figure 3). Furthermore, the occurrence of ward overflow differed significantly, with 80 occurrences being reported prior to the addition of the ORs and 248 occurrences being reported after the addition. Other issues also differed significantly between the study periods (nine prior to addition vs. 46 after addition). The occurrence of cancellation due to scheduling date error (22 vs. 66) and unavailable surgeons (11 vs. 5) did not differ significantly between groups.


The results of this study demonstrate that: 1) the increased operative capacity may not prevent day-of-surgery cancellation and 2) the overall rates of elective surgery cancellation increased after the installation of additional ORs, which may have occurred due to a bottle-neck effect in the general ward.

The primary reason to increase OR capacity was to permit more operations by reducing overbooking. However, our results demonstrated that the overall number of scheduled cases (2494 vs. 2886 before and after, respectively; P >0.05) and cancelled cases (512 vs. 688 before and after, respectively; P >0.05) did not increase, even though OR capacity increased. Indeed, the number of scheduled cases increased by 11.5% while the number of cancelled cases increased by 13.4% during the period of the investigation. Accordingly, the cancellation ratio increased after the installation of two additional ORs (20.5% prior to installation vs. 23.8% following installation, P <0.05).

These findings indicate that prevention of day-of-surgery cancellation due to departmental issues, especially ward overflow, is of the utmost importance. Robb et al (12) reported that elective surgery was often cancelled due to increasing medical admissions. According to their report, the number of elective operation cancellations due to "no bed" was 31% between April, 1997 and March, 1998 and this increased to 62.5% between April, 2001 and March, 2002. However, medical admission only increased by 28.39% during the same interval.

One promising method to prevent day-of-surgery cancellation due to ward overflow is to decrease the length of hospital stay. Decreasing the length of hospital stay can open up new beds for surgical patients. In addition, by discharging patients more quickly, hospitals can reduce their overall health care costs, even if patients continue to receive care on an out-patient basis (13). Another option to reduce the rate of cancellations is to perform more operations on an outpatient basis. This allows patients to come in early on the morning that they are scheduled to undergo surgery. During the course of our study, patients had to spend extended amounts of time in the post-anaesthesia care unit during recovery if all of the beds on a floor were occupied. Boothe and Finegan (14) demonstrated that a same day admission process reduced cost and enhanced hospital productivity. Specifically, they found that increasing the number of out-patient operations resulted in a 15.7% decrease in the number of occupied surgical beds and a 12.2% increase in total case flow.

Patient medical problems were the second-most common cause of cancellation. Among medical problems, abnormal liver function tests, electrocardiograms and chest X-rays were responsible for greater than 50% of the cancellations in both groups. During the preoperative evaluation procedure conducted at our institute, the anaesthesiologist visits the patient at the ward on the day before surgery and all patients at the ward have a predetermined set of laboratory results based on tests that were performed in the surgical outpatient department. Those patients who had liver function, electrocardiogram or chest X-ray test results that were abnormal could not be candidates for operation if the hospital opened a preoperative evaluation clinic. However, if the patients who had abnormal laboratory results were managed on an out-patient basis, the beds occupied by these patients could be used for patients who were unable to undergo operation due to ward overflow.

These results indicate that hospitals should optimise their OR schedules to ensure smooth patient flow prior to considering an increase in OR capacity. The optimised OR schedule should comply with all operating constraints, while balancing the demand for surgical beds with the maximum profit or revenue that can be obtained from each bed (15,16).

This study was limited because it was performed at only one university hospital. However, a survey of hospitals in Switzerland (18) showed that 50% had a formal OR director and that, in most cases, this director was a surgeon. In the absence of a formal OR director, OR time is allocated by surgeons or departmental staff using historical data. The use of such a system is likely to result in OR capacity being increased in an attempt to increase the reimbursable surgical volume prior to development of an optimal scheduling strategy. However, in a time of diminishing revenue and financial resources, hospitals may be reluctant to allocate funds for staffing of a formal OR director (17). This study was also limited in that the hospital evaluated here only performed outpatient surgery on a limited basis; therefore, outpatient surgery was excluded. In Western countries, many operations are conducted on an out-patient basis. Indeed, it is estimated that greater than 70% of operations in the US are conducted on an ambulatory basis (18). In Spain, 34.3% of anaesthesia is performed on out-patients (19). Conversely, out-patient surgery is only performed on a limited basis in Eastern countries. For instance, day surgery is conducted in the paediatric field in Japan to treat conditions such as inguinal hernia (20). Additionally, Srisawasdi et al reported that 6.6% of anaesthesia in Thailand was administered on an out-patient basis in 2007 (21). Based on these limitations, our results should only be used as a reference for institutions that do not have a formal OR director and in which out-patient anaesthesia is only performed on a limited basis.

In conclusion, increasing the OR capacity is not an appropriate method of preventing the cancellation of operations and it can actually cause other issues such as administrative problems. However, different management strategies such as decreasing the length of hospital stay, implementing a preoperative evaluation clinic, and changing the OR scheduling strategy to maximise the use of the operating time block may be helpful for preventing the cancellation of operations.


The Medical Collaborating Center of Seoul National University Hospital assisted with the statistical analysis in this study.

This work was presented, in part, at the 2006 Annual Meeting of the Canadian Society of Anesthesiologists in Toronto, Canada.

Address for reprints: Dr Seong-Ho Chang, Department of Anesthesiology and Pain Medicine, Korea University College of Medicine, #126-1, 5-Ga, Anam-dong, Sungbuk-gu, Seoul 136-705, Republic of Korea.

Accepted for publication on September 28, 2008.


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S.-Z. YOON *, S. I. LEE ([dagger]), H. W LEE ([double dagger]), H. J. LIM ([double dagger]), S. M. YOON ([double dagger]), S. H. CHANG ([double dagger])

Department of Anesthesiology and Pain Medicine, Korea University, Seoul, Korea

* M.D., Ph.D., Clinical Associate Professor. ([dagger]) M.D., Chief Resident. ([double dagger]) M.D., Ph.D., Professor.
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