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Quality improvement

Unplanned surgical reoperations in a tertiary hospital: perioperative mortality and associated risk factors

Rama-Maceiras, Pablo; Rey-Rilo, Teresa; Moreno-Lopez, Esther; Molins-Gauna, Nieves; Sanduende-Otero, Yolanda; Pensado-Castiñeiras, Alberto

Author Information
European Journal of Anaesthesiology: January 2011 - Volume 28 - Issue 1 - p 10-15
doi: 10.1097/EJA.0b013e32833e33b0



Unplanned surgical reoperations are major events for patients and have considerable impact on the healthcare system.1 Reoperation rates vary in relation to both the type of initial surgery and caseload.1,2 Reported rates range from 0.6 to 11.2%.2–12

The reoperation rate has been used as a criterion for evaluating surgical department practice8,9,13 or even overall hospital care, though no consensus has been reached on the appropriateness of this parameter11,14 and its use as a quality indicator can be complicated.9 The documentation and quantification of reoperations has been found to reduce the incidence.3

Unplanned reoperations increase the burden on the health system as they result in operating theatre occupation, affect surgical waiting lists and lead to longer hospital stays,15 therefore, raising costs.5,8,10,16,17 They generate user dissatisfaction and distrust18 and affect staff self-confidence. Reoperations can increase the rates of morbidity19 and mortality.9,11 Although several studies have evaluated the importance and impact of unplanned reoperations, especially for specific surgical procedures,2,5,8,9,11 we lack data on overall reoperation rates for European tertiary hospitals. The aim of this study was to estimate the unplanned reoperation rate in an 800-bed tertiary hospital, one facility in a larger teaching-hospital complex in Spain. The study also aimed to estimate mortality rates related to unplanned reoperation and determine associated risk factors of mortality.


The present study was part of a quality improvement project approved by the ethics committee of the Complejo Hospitalario Universitario de A Coruña, Spain (President B. Acea) on 6 March 2006. Because this was an observational study with no interventions other than routine care, specific informed consent was not considered necessary. Data related to patients' identity were not gathered.

Study population

Nonpaediatric patients (aged >16 years) who underwent any major noncardiac surgical procedure and were admitted to the postoperative care unit (POCU) from 1 May 2006 to 31 March 2008 were included. The hospital is part of a tertiary teaching complex that covers a variety of surgical specialties, including general, orthopaedic and trauma, vascular, thoracic, plastic and neurosurgery as well as procedures in urology and transplantation. Between the end of surgery until transfer to a conventional ward, patients are admitted to the POCU, which is coordinated by the Department of Anaesthesiology and Perioperative Medicine. There are 12 postanaesthesia recovery beds for short stays of up to 24 h, and 18 postoperative critical care beds. In 2009 (the year following data collection), the POCU assigned 5272 patients to short-stay beds and 1225 to critical care beds. Patients were discharged from the POCU when awake, alert and able to breathe properly without assistance; when vital signs (blood pressure and heart rate within 20% of preoperative value) were stable; and when there was no active nausea, vomiting, agitation or pain on moving, coughing or breathing deeply. In addition, surgical drains had to be clear, showing no signs of active bleeding or fistula.

Although cardiac surgery procedures, including heart transplantation, are also performed in this hospital, postoperative care takes place in a different intensive care unit only partially coordinated by the anaesthesiology department; cardiac surgery patients were, therefore, not included in this study. Likewise, outpatient surgery, obstetrics, gynaecology, paediatric surgery, maxillofacial surgery, ophthalmic surgery and ear, nose and throat surgical procedures are all performed in other divisions of the medical complex and were not included in this study.

Case identification

Patients who underwent unplanned reoperation during the study period were identified from medical records. Data for analysis were taken directly from the hospital's database.

Definition of unplanned reoperation

Unplanned surgical reoperation was defined as any unexpected surgical procedure performed within 30 days after the initial surgery in response to any complication resulting directly or indirectly from the initial operation. Surgical procedures that were planned for two stages or that were required because of nonsurgical complications (e.g. tracheostomy in long-term mechanically ventilated patients) were excluded.

The indications for reoperation were divided into nine categories according to the surgeon's diagnosis on ordering the procedure (Table 1).20

Table 1
Table 1:
Indications for reoperation

Data collection

We recorded age, sex, American Society of Anesthesiologists (ASA) physical status classification, surgical risk class for the initial operation (high, intermediate or low) according to the joint guidelines of the American Heart Association and American College of Cardiology of 2000,21 type of surgery (elective, emergency or transplantation), indication for reoperation, time of reoperation (patient reoperated before discharge from the POCU or after discharge to the ward), reoperated body cavity, the number of reoperations, length of stay in the POCU and total in-hospital length of stay after the initial operation.

Patients were followed from the first reoperation until they were discharged from the hospital. In-hospital mortality was recorded.

Statistical analysis

Reoperated patients were analysed as survivors or nonsurvivors based on the outcome at discharge from the hospital. Continuous data had a nonnormal distribution according to the Kolmogorov–Smirnov test and were, therefore, described by median and interquartile range (IQR). Categorical variables were expressed as absolute number of patients and percentages.

Factors associated with mortality in reoperated patients first underwent univariate analysis for comparisons between survivors and nonsurvivors. The Mann–Whitney U-test was used for continuous variables, and the Fisher's exact test or the χ2 test, as appropriate, for categorical data.

The variables associated with mortality in the univariate analysis were introduced into a logistic regression model to determine those variables independently associated with mortality after reoperation. The number of candidate covariates was reduced so that the number of observations with the least common outcome (nonsurvivor patients) was equal to at least 10 times the number of predictors.22 The selection was made based on the results of the univariate analysis, in which covariates with the lowest P values were included in the model.23

We also determined odds ratios (ORs) and 95% confidence intervals (CIs) for risk factors. A value of P less than 0.05 was considered statistically significant. Analyses were performed using the SPSS version 15 software package (SPSS Inc., Chicago, Illinois, USA)


A total of 11 468 patients were treated surgically and admitted to the POCU during the study period; 381 (3.3%) had to be reoperated at least once within 30 days of the initial operation (Table 2). The total number of surgical procedures was 12 022; 554 of them (4.6%) were reoperations. Patients underwent reoperation between one and seven times (Fig. 1), with a median of 1 (IQR, 1–2) reoperation per patient.

Table 2
Table 2:
Demographics of included patientsa
Fig. 1
Fig. 1

Eighty-three of the 381 reoperated patients (21.8%) died after an unplanned reoperation; in contrast, 322 (2.9%) of 11 087 patients who did not undergo reoperation died (Table 3). Reoperation was performed in the peritoneal cavity in 226 patients (59.3%) and extraperitoneally in 56 (14.7%). Procedures were performed on extremities or the spine in 37 patients (9.7%), intracranially in 30 (7.9%), in the chest in 25 (6.5%), in the neck and/or head in three (0.8%) and endoscopically in four (1.0%).

Table 3
Table 3:

The main indications for the second or subsequent intervention were postsurgical bleeding (26.3%) and infections of all types (31.2%, including the categories of infection/abscess, intestinal fistula and surgical wound problems; Table 4).

Table 4
Table 4:
Indications for the first and subsequent reoperationsa

Univariate analysis identified 13 factors potentially associated with risk for or protection against in-hospital mortality in reoperated patients (Table 5). On multivariate analysis, five factors were identified as independent risk factors for in-hospital mortality in reoperated patients (Table 6).

Table 5
Table 5:
Factors associated with in-hospital mortality in reoperated patients (univariate analysis)a
Table 6
Table 6:
Factors associated with in-hospital mortality in reoperated patients, after multivariate analysis using logistic regression model


This observational study confirms that unplanned reoperation adds considerable risk above the initial risk associated with the first procedure surgery and accompanying anaesthesia to the extent that mortality increases significantly after reoperation. Five risk factors for mortality in these reoperated patients were identified.

The rate of unplanned reoperation of 3.3% in our study is comparable to rates reported in other studies,8,11 though the definitions of reoperation and the patient populations have differed. In the present study, scheduled reoperations and foreseen two-stage surgery were not considered. Such reoperations are performed when definitive repair in a single procedure would probably exceed the patient's physiologic reserve or would be technically impossible. Furthermore, unlike unplanned reoperations, scheduled second procedures are associated with a lower mortality rate.24 The mortality rate of 21.7% we observed in patients after unplanned reoperation was also similar to rates reported by other authors.3,5,7,8

The classification of indications for reoperation we applied is partly based on previous publications8,20 but has also emerged from the authors' own unreported observations; it was developed to respond to the variety of surgical procedures gathered in this study. The differentiation between infection/abscess and fistula, which were placed in two different categories, was established because fistulas are associated with widespread infection and the associated mortality rate can be higher.20 Studies have suggested that 17–31% of unplanned reoperations are due to infection;3,10 in our study, the rate corresponding to all infectious complications was at the high end of this range (31.2%). The rate of unplanned reoperation related to haemorrhage in our study (26.3%) was similar to rates reported elsewhere.6,25

Some studies investigating factors associated with mortality in patients undergoing unplanned reoperation have identified risk factors that were similar to the ones we observed. Thus, the number of reoperations10,26 and patient age27–29 have both been reported to increase risk of mortality, though some authors have not found this association.3 A recent study of patients who had undergone colorectal surgery suggested a relation between high mortality and acute abdomen as a reason for reoperation.10

The limitations of this study include the recruitment of cases from a single hospital and from different surgical disciplines, which have different reoperation rates. Thus, findings cannot be generalised to all settings. Furthermore, only in-hospital follow-up is reported; therefore, the results probably reflect a best-case scenario. It is also important to remember that the CIs for the ORs of some variables associated with mortality were large; therefore, the association between these variables and mortality after unplanned reoperation may be weak. Finally, multivariate modelling reflects association but not causality; it must be remembered that unmeasured factors may also have had an impact on mortality in this study.

In summary, the major challenge that unplanned reoperations represent for a tertiary-care hospital is evidenced by high mortality after these subsequent procedures. The risk factors we have identified may help care providers guide patients and relatives through the decision-making process. Age, acute abdomen and reoperation involving the thoracic region indicate a need for vigilance, as they were associated with mortality after unplanned reoperation in our study. High patient risk is also indicated when several reoperations are performed or when reoperation occurs in the most critical postoperative period before transfer to the ward.


We would like to thank Mary Ellen Kerans and Martha Messman for assistance with aspects of English-language expression in different versions of the manuscript reporting this study.

This research was supported by the Department of Anaesthesiology and Perioperative Medicine, Complejo Hospitalario Universitario A Coruña, Coruña, Spain.

None of the authors has any conflict of interest.


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in-hospital mortality; postoperative complications; reoperation

© 2011 European Society of Anaesthesiology