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Logistics and economics

A clinical pathway in a post-anaesthesia care unit to reduce length of stay, mortality and unplanned intensive care unit admission

Eichenberger, Alain-S.; Haller, Guy; Cheseaux, Nicole; Lechappe, Vincent; Garnerin, Philippe; Walder, Bernhard

Author Information
European Journal of Anaesthesiology: December 2011 - Volume 28 - Issue 12 - p 859-866
doi: 10.1097/EJA.0b013e328347dff5



Every year, about 10 000 per 100 000 population in the western world undergoes a surgical procedure under anaesthesia.1,2 The occurrence of post-operative complications has a major impact on survival after major surgery3 and in older patients.4 During the first few days after surgery, pulmonary complications, myocardial infarction, acute cardiac failure, bleeding and delirium can be detected5,6 and successfully treated in well organised post-operative care units, resulting in increased survival.7 High standards of post-operative care prevent many of these adverse events and unplanned admissions to the ICU.8 Post-anaesthesia care units (PACUs) with facilities for prolonged and intermediate inpatient care,9 an adequate nurse-patient ratio and daily rounds play a key role in the rapid detection and treatment of early post-operative complications in patients at risk and contribute to decreased post-operative mortality.10

Appropriate and effective use of PACUs is crucial to ensure adequate immediate post-operative care. Patients with no post-operative complications need to be discharged as soon as possible to ensure availability of beds for new patients transferred from the operating theatres. If complications occur, patients require immediate, additional care resources. A key factor in ensuring effectiveness of the PACU is the maintenance of a fine balance of resource utilisation between patients who need more care and those who do not. ‘Clinical pathways’ offer promising perspectives in ensuring the use of appropriate resources in PACUs. These are defined as structured, multidisciplinary care plans detailing essential steps in the care of patients according to clinical status,11 and are designed to support clinical, non-clinical and resource management. They are also called ‘critical pathways’ or ‘care maps’ and have been used successfully for the care of patients with major vascular, thoracic or congenital heart defect surgery.12–14 They have been shown to decrease hospital length of stay and costs, but no impact on post-operative mortality or morbidity has been demonstrated. No benefit in use of resources was seen when implemented in surgical ICUs.15

There are no published studies about the use of clinical pathways in PACUs for inpatients and their impact on length of stay in the PACU and on post-operative outcomes. We, therefore, wished to establish whether the implementation of a clinical pathway in our PACU had an influence on length of stay, post-operative mortality and the incidence of unplanned ICU admission.


Study site and baseline characteristics

Ethical approval for this study (09–074R) was provided by the Ethical Committee NAC of Geneva University Hospitals, Switzerland (Chairperson Professor J S Lacroix). The Ethical Committee waived consent for this retrospective study. We included patient data collected between 1 January 2007 and 31 July 2007, and 1 January 2008 and 31 July 2008.

Geneva University Hospital in Switzerland is a tertiary teaching hospital with all types of surgical, medical and radiological departments. All elective and non-elective inpatients who have undergone a surgical or endoscopic procedure under anaesthesia are admitted to our central PACU except for patients with multiple trauma, persistent intra-operative shock, transplantation, cardiac surgery and intra-operative respiratory failure, who are treated post-operatively in the ICU. The procedures preceding admission to the PACU include liver, pancreatic or any other major abdominal surgery, complex vertebral surgery, all types of thoracic surgery, ear nose and throat surgery and central and peripheral vascular surgery. The unit offers intermediate care for these high-risk surgical patients who may require temporary non-invasive ventilation, haemodynamic support and continuous monitoring. The unit has 15 beds and is part of the Division of Anaesthesiology. Of these 15 beds, a virtual subunit with a maximum of six beds is organised as an intermediate care unit (High Dependency Unit); the other beds are used as a virtual post-operative recovery subunit. The staffing ratio is one PACU nurse to three beds (8-h or 12-h shifts) corresponding to the regulatory requirement. At least one nurse in each shift is a specialised nurse in anaesthesiology or intensive care. Medical cover is provided by one resident anaesthesiologist supervised by a senior anaesthesiologist during the day (07.00 to 19.00 h). During the night and weekends, an on-call resident and an in-house fellow anaesthesiologist are available 24 h a day. The hospital lacks a formal surgical intermediate care unit, except for neurosurgical patients.

We admit about 8000 patients every year to our PACU. Patients stay between 1 h and 3 days, depending on the type of surgery, anaesthetic technique and co-morbidity. Until November 2007, we had no defined criteria for management or discharge of patients, that is, no clinical pathways. Crowding, delay in discharge and limited nursing and medical resources led us to implement a post-operative clinical pathway in November and December 2007.

Intervention: implementation of the clinical pathway

The medical and nursing heads of our PACU conducted a critical review of current practices several months before implementation of the clinical pathway. The review showed that the absence of predefined management and discharge criteria resulted in insecurity on the part of the PACU physicians, placed stress on the nursing staff and delayed the admission of patients from the operating theatres. We, therefore, introduced a two-track clinical pathway that clearly defined and coordinated medical and nursing interventions, including diagnostic tests, medications and standardised patient discharge criteria (Fig. 1).

Fig. 1
Fig. 1:
no caption available.

The first track is a nurse-driven fast-track programme for healthy patients [the American Society of Anaesthesiologists (ASA) 1–2]. The second track is a physician-driven slow-track programme for patients in poor physical condition (ASA 3–5) who have undergone minor or major surgery or developed post-operative complications (Fig. 2). This process intervention was performed with identical staffing in the PACU.

Fig. 2
Fig. 2:
no caption available.

Fast-track programme

Fast-track programme patients or recovery room patients are managed and followed up by PACU nurses. Standard post-operative care is provided as prescribed by the anaesthesiologist(s) in charge during the intra-operative period. Systematically and at regular intervals of 15 min, the nurse in charge evaluates patients’ vital signs using the Aldrete score,16 and pain is assessed using a verbal numeric rating scale (range, 0 no pain, 10 maximal pain).17 Discharge is performed without further communication with the PACU anaesthesiologist if the Aldrete score is at least 8 and the verbal numeric rating scale of 3 or less. If patients have a score less than 1 for one or more of the five items of the Aldrete score (meaning a significant complication such as hypotension, apnoea, absence of movement or loss of consciousness), the PACU anaesthesiologist is summoned, a diagnostic procedure is started and an adapted treatment plan established.

Compared with preexisting conditions without the clinical pathway, the following processes were changed for this group of patients: systematic use of the Aldrete score and systematic discharge without reference to the PACU physician. The aims of the fast-track programme were to decrease length of stay and to increase the flow of patients through the PACU.

Slow-track programme

Slow-track programme patients or intermediate care patients are managed by the PACU anaesthesiologist together with the PACU nurses. Systematically, a formal handover between intra-operative anaesthesiologist and PACU anaesthesiologist is performed for all patients who have undergone major surgery or emergency surgery, and for those with a major illness. This handover includes the use of a written anaesthesia and surgical protocol and information about post-operative treatment prescriptions. It integrates four key elements: the patient's pre-operative state, the operation performed, any intra-operative problems encountered and analgesic technique. After a first evaluation of the cardiopulmonary and pain status, including blood gas analysis, the PACU anaesthesiologist and nurse establish a care plan.

A standard set of diagnostic tests for the investigation of early post-operative complications (oxygen desaturation, hypotension, hyperglycaemia, tachycardia or fever) and treatment guidelines for common serious complications were designed. All procedures and treatments are recorded in a log used by all staff members in the PACU. The log also defines how care is coordinated between PACU anaesthesiologists and nurses. Treatment strategies were most often a combination of interventions: for instance, early antibiotics, early mobilisation and continuous positive airway pressure (CPAP) for hypoxaemic pneumonia. Blood glucose control is performed systematically and treatment with insulin is provided using an individually adapted scheme avoiding extremes of hyperglycaemia and hypoglycaemia. A restrictive transfusion policy was systematically adopted. In patients with hypertension and tachycardia, a β-blocker is used as first-line treatment. Overhydration is avoided, and patients with hypotension and epidural analgesia often receive a continuous low-dose infusion of noradrenaline on the first post-operative night. In patients with unexplained blood pressure instability, active steps are taken to exclude myocardial infarction. Similarly, the possibility of cardiac failure is considered in patients with unexplained hypoxaemia.

Systematically, all patients are reviewed on two rounds per day, one in the morning and one in the evening. Participants in these rounds are the nurse in charge, the PACU anaesthesiologist and the ICU certificated director of the PACU. The progress of each patient and results of investigations are discussed during the round; diagnoses are established and treatment strategies are adapted accordingly. If necessary, further diagnostic investigations or specific consultations are identified during rounds.

Discharge of patients in the slow-track programme is based on an Aldrete score at least 8 and normal blood gas analysis: arterial blood pH more than 7.33, serum lactate less than 2 mmol l−1, paO2 more than 7.5 kPa (except for patients with preexisting pulmonary disease) and blood glucose less than 10 mmol l−1. The PACU physician in charge decides on discharge and always prepares a brief written handover with the performed assessments and follow-up recommendations for ward physicians.

Adherence to the clinical pathway is ensured during daily rounds by the medical head of the PACU, and during weekly quality control, feedback and information meetings.

Compared with the preexisting system without the clinical pathway, the following processes were changed: systematic handover between intra-operative anaesthesiologist and PACU anaesthesiologist, systematic blood gas analysis on admission, systematic and comprehensive review of each patient's condition during rounds with an ICU certified physician, systematic use of standardised care for regular post-operative events, strict discharge criteria including predischarge blood gas analysis and written handover including assessments and recommendations for patients with new post-operative problems. The aims of the slow-track programme were to increase the quality of care and care effectiveness in PACU and to decrease complications after discharge, that is, post-operative mortality and unplanned ICU admission.

Study design

We performed a before and after study comparing length of stay in the PACU, in-hospital mortality and unplanned admissions to the ICU after PACU stay. We included all patients who underwent anaesthesia and were admitted immediately afterwards to the PACU during the first 7 months (1 January to 31 July) before (2007) and after (2008) implementation of the programmes. Patients transferred later from surgical wards to the PACU for monitoring and advanced care were excluded.

We retrieved data from the Anaesthetic Information system and the hospital administrative databases. The Anaesthetic Information system is a computerised patient information system used for all patients who undergo in-hospital or ambulatory surgery with an anaesthesiologist in attendance. Data are recorded by the anaesthesiologist in charge on computers available in each operating theatre during or at the end of surgery. Data related to the PACU are recorded in the computerised system by the PACU secretary and nurses. Recorded data include the age and sex of the patient, ASA physical status score, the anaesthetic and surgical techniques employed, general information such as timing, duration and sequence of procedures, the length of stay in the PACU and emergency status. The hospital administrative database is used for financial purposes and includes administrative information such as length of stay in the hospital, in-hospital mortality and unplanned ICU admissions (during the whole post-operative period) after a stay in the PACU. The hospital administrative database does not collect data on post-operative complications or the causes of death or unplanned ICU admission. These outcome data are extracted from patient discharge reports and entered by professional coders in the hospital administrative database. The database is managed by the Unit for Medico-Economic Investigations. For this study, we merged the two datasets using a unique patient identification number included in both. To confirm the overall accuracy of the process, we randomly checked 10% of the final dataset against the original files. To ensure quality of PACU data, all information recorded on the PACU electronic information system was double-checked for coherence and completeness daily by the PACU secretary, and monthly by the head of the PACU. Mortality data and unplanned admissions to the ICU were double-checked against medical records.

Statistical analyses

Anaesthetic and surgical procedures and patient characteristics were described by percentages for categorical variables and medians with interquartile range (IQR) for numerical variables, depending on distribution. We considered the ASA physical status classification as a surrogate co-morbidity score because it is routinely used and validated as a predictor of post-operative anaesthesia-related complications and mortality.18 We divided the score into two separate categories: patients with no or minor co-morbidities (ASA 1–2) and patients with major co-morbidities (ASA 3–5). Age was divided into three equal tertiles. We recoded and aggregated surgical procedures according to eight categories performed in our hospital. We stratified surgery into high-risk and low-risk surgery according to the nature of the procedure performed.19 Length of stay in the PACU was transformed into minutes. Mortality and unplanned admissions to the ICU after a stay in the PACU were considered as categorical variables.

To estimate the impact of the clinical pathway on patient outcomes, we performed three separate analyses, measuring the differences in length of stay in the PACU; in-hospital mortality; and unplanned admissions to ICU after a stay in the PACU, before and after implementation of the pathway.

Left-skewed PACU length of stay data were log-transformed and compared using the unpaired Student's t-test. Multivariate analyses (linear regression) were performed to adjust for differences between the two periods and the confounding effect of age, sex, type of surgery, type of anaesthesia care and emergency status. We built multivariate models using a forward selection technique, considering only univariate significant factors with a P value less than 0.10. Variables that were still significant at P less than 0.05, or which had strong clinical significance (age, emergency status) were retained. An interaction term was created and introduced into the model to account for the interaction phenomenon between emergency status and the type of surgical and anaesthetic procedure. The assumptions of normality and residual distribution were tested.

To compare differences in mortality and the proportions of unplanned admissions to ICU between the two groups, we used the χ2 test and calculated the odds ratio (OR) with 95% confidence intervals (95% CIs). Multivariate analyses (logistic regression) and forward selection techniques were performed to assess differences in mortality and unplanned admissions to ICU between the two groups with adjustment for the confounding effects of age, sex, type of surgery, type of anaesthesia, risk of surgical procedure and emergency status.

Goodness-of-fit and C indices for the two models were tested. The significance of the Hosmer–Lemeshow goodness-of-fit test ranged between 0.19 and 0.85. C indices were all between 0.70 and 0.94 across the different analyses. Final results are expressed as unadjusted and adjusted 95% CI and P values. A P value of less than 0.05 was considered statistically significant. We used the STATA statistical software (version 10.0/IC 2007; StataCorp, College Station, Texas, USA) for all analyses.


The number of patients, patient characteristics, ASA scores and type of surgery were similar before and after implementation of the clinical pathway (Table 1). The number of interventions performed under general anaesthesia was greater in the second period (n = 3345) than in the first period (n = 3030), but fewer patients who had undergone high-risk interventions (P < 0.001) and more patients who had undergone elective procedures were admitted to the PACU during the second period (P = 0.018).

Table 1
Table 1:
Patients’ characteristics before and after implementation of the quality improvement programme

After implementation of the clinical pathway, the median PACU length of stay for all patients decreased from 163 min (IQR 107–291) to 148 min (IQR 96–270), and for ASA 1–2 patients from 152 min (IQR 102–249) to 135 min (IQR 90–227). After adjustment for differences in patients and procedures between the two periods, the difference for ASA 1–2 patients was statistically significant (adjusted P < 0.001; Fig. 3). There was no difference in PACU length of stay of ASA 3–5 patients [203 min (IQR 125–464) versus 197 min (IQR 117–481; adjusted P = 0.768)].

Fig. 3
Fig. 3:
no caption available.

After implementation of the clinical pathway, in-hospital mortality decreased significantly from 68 patients (1.5%) to 39 (0.8%); adjusted OR (95% CI) was 0.36 (0.21–0.59) (P < 0.001; Table 2). In patients with ASA grades 3–5, mortality was nearly halved; adjusted OR (95% CI) was 0.40 (0.23–0.66) (P < 0.001). The number of unplanned ICU admissions after a stay in the PACU decreased from 113 (2.5%) to 90 (1.9%); adjusted OR (95% CI) was 0.70 (0.51–0.96) (P = 0.02; Table 2).

Table 2
Table 2:
Differences between in-hospital mortality and unplanned admissions to the ICU before and after implementation of the clinical pathway, by the American Society of Anaesthesiologists grade


The implementation of the clinical pathway in our PACU improved patient flow with a significant decrease in PACU length of stay of 11.2% in ASA 1–2 patients. It also significantly improved post-operative outcomes with an overall decrease in post-operative in-hospital mortality of 36.6% and unplanned ICU admissions of 23.2% in ASA 3–5 patients. These improvements remained significant even after adjustment for case-mix differences.

We found a decrease in PACU length of stay using discharge criteria in our fast-track programme for recovery room patients. This is consistent with a previous publication on PACU management. Brown et al.5 observed a decrease in PACU length of stay from 133 to 100 min in elective patients undergoing general anaesthesia following introduction of discharge criteria. Our study confirmed these findings in a more heterogeneous population, as we included both elective and emergency procedures and all types of anaesthetic techniques.

We also found that the introduction of standardised and well coordinated intermediate care with the slow-track programme improved outcome without increasing length of stay in the PACU. These results are in line with studies showing that patients treated in well managed ICUs,7 PACUs and intermediate care units10 had better outcomes than patients treated in standard units. It is likely that these favourable post-operative outcomes were of multifactorial origin, similar to the findings of a recently published quality improvement programme after major orthopaedic surgery in which the incidence of post-operative myocardial ischaemia was reduced after implementation of a bundle of therapeutic interventions.20

The slow-track programme integrated systematic and standardised diagnostic procedures. This allowed early recognition and management of post-operative complications and resulted in reduced post-operative mortality and unplanned ICU admissions after a stay in the PACU. A multicentre study21 assessing surgical inpatients showed a huge variance in post-operative outcome among hospitals and timely detection and treatment of complications was suggested as the key factor in reducing mortality.22

The slow-track programme has some similarities with the World Health Organization's Safe Surgery Saves Lives programme.23 Both use ‘time out’ and ‘sign out’ elements. Regular rounds by our PACU medical teams were performed (‘time out’) during the day for patients in the slow-track programme, and all diagnoses and treatments during the PACU stay were transmitted to the surgical ward staff (‘sign out’). This may have improved communication between the PACU anaesthesiologists and nurses, and between the PACU and surgical ward teams, factors known to improve quality of care.24 In addition, handover may have had a positive impact on outcome after the implementation of our clinical pathway in the PACU, particularly as the slow-track programme included a new written form to be used for information handover between the PACU and the surgical ward. This is an important aspect because the post-operative handover process on discharge from the PACU is a particularly critical period. Information needs to be transferred from a unit with continuous patient monitoring and a patient : nurse ratio of 3 to a unit without patient monitoring and a patient : nurse ratio of 8. When the handover is formalised, the impact on outcome is likely to be highly positive. This has been studied for the handover between operating theatre and PACU, but less is known about the handover between the PACU and surgical units.25–27 Our study did not investigate specifically this aspect as we performed a global intervention, a clinical pathway. As a result, we were unable to assess the specific impact of the handover protocol.

The decrease in post-operative mortality may also be related to the decreased likelihood of unplanned ICU admission from PACU. In one study, unplanned ICU admission after non-cardiac surgery in older patients was associated with a considerable 30-day mortality of 21%.28

An increased risk of overlooked serious post-operative complications requiring unplanned ICU admission and increased mortality might be expected as a result of the reduction in PACU length of stay because of the nurse-driven fast-track programme. We did not observe this. Indeed, the number of unplanned admissions to ICU and in-hospital mortality did not increase, but decreased, after implementation of the fast-track programme. As a result, a fast-track programme for ASA 1–2 patients undergoing minor surgery can be considered safe and contributes to reduced crowding in the PACU. This is a particularly important aspect because crowding has caused delays in the treatment of pain and administration of antibiotics, and has often been associated with patient dissatisfaction.29

Our clinical pathway, like others described for surgical patients,12–14 may have been cost-effective because the allocation of PACU staff was identical in both periods investigated, and because fewer patients needed expensive ICU beds. Physicians spent more time with patients allocated to the slow-track programme, identified more potential complications that were associated with lower mortality and unplanned ICU admission, but probably increased the number of diagnostic work-ups and concomitant costs.30 These ‘side-effects’ have to be considered in the estimation of costs.

Although the introduction of the pathway showed an improvement in patient turnover and a positive impact on outcome, our analysis does have some limitations. First, the adherence rate of PACU personnel to the pathway could not be measured during the study period because of limited documentation in our Anaesthetic Information system and hospital administrative database. However, the daily rounds of the head of the PACU and corrective action taken at weekly meetings ensured high adherence. Second, as we used existing data, a number of confounding factors may not have been measured (e.g. variation of case-mix, staff characteristics). This problem was minimised by comparing the same periods of the year before and after implementation of the pathway. Third, because our study data were collected retrospectively, they lacked the precision and reliability of well defined prospectively collected research data. We minimised this risk by using a large number of data extracted from the hospital administrative database. As these data are used for financial purposes, they are recorded by professional coders and their validity is regularly double-checked. Administrative data are less detailed than the data that we collect prospectively. Consequently, no post-operative complications were reported in our investigation; we used the rates of unplanned ICU admission as an indicator of the rates of major post-operative complications. Fourth, our results cannot be generalised to other hospitals because our study included only one teaching hospital with a PACU offering facilities for prolonged and intermediate inpatient care and with a high proportion of emergency patients. Fifth, although we found a significant improvement in patient outcome after implementation of our pathway, our study was not randomised, and there may be other explanations for the changes observed. We tried to minimise this by adjusting the analysis for differences in patient characteristics, emergency status and types of surgery and anaesthesia between the two periods compared. We used multivariate models to adjust for the confounding effect of these differences on mortality, length of stay and unplanned ICU admissions. There may be a number of other differences between the two periods that were not accounted for and could potentially have influenced the results of our study. However, the high predictive values of the different multivariate models (C indices between 0.70 and 0.94) suggest that the influence of these factors was probably limited.

Ideally, a prospective cluster randomised controlled study (parallel or stepped wedge) should be performed to confirm our findings. However, such a study would be very difficult to perform because PACUs rather than patients would have to be randomised corresponding to a cluster randomisation to minimise distortion of practices in one PACU. An investigation focused on the type of patients who benefit most from such a pathway and the type of complications decreased by this approach should be performed, including calculations of cost-effectiveness.

In conclusion, the introduction of a clinical pathway approach in a PACU can significantly contribute to a reduction in length of stay in the PACU for uncomplicated patients and can also improve outcome in high-risk, ASA 3–5 patients.


The authors would like to thank the nurses of the PACU, University Hospitals of Geneva, for their contribution in daily practice. None of the authors has financial support or sponsorship for this retrospective study. None of the authors has any conflict of interests.


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complications; mortality; post-operative; quality improvement

© 2011 European Society of Anaesthesiology