Early ambulation is now recognised as an intervention that confers many positive benefits to patients following cardiac surgery. However, there is lack of clarity as to the optimum time for the patient to perform early ambulation. A focused question was developed to ascertain whether early ambulation within 24 hours after extubation is more effective compared to ambulation 24 hours or more following extubation. The clinical question guided the search and retrieval of 6 studies that were subsequently appraised. There are benefits and many limitations of the chosen studies and do not provide sufficient evidence to answer the clinical question definitively. A more refined question is proposed.
The conventional postoperative management of cardiac surgery is to have the patient remain on bedrest for days at a time to ensure rest and healing. However, there is increasing recognition of the benefits of mobilisation early in the postoperative period. The benefits include a reduced risk for pneumonia because of enhanced expectoration of respiratory secretions and also a lower risk for deep vein thrombosis (DVT) and pulmonary emboli (Freeman & Maley, 2013). A decline in the risks for complications is associated with shorter hospital stays and maintenance of functional ability without the need for rehabilitation.
Changes have since been made in clinical practice to enable early ambulation so that patients can optimise the benefits. Extubation is performed earlier, and the patient care involves the performance of progressive mobility exercises. For instance, the first postoperative day is devoted to bed-to-chair transfers that is done twice or thrice with room and hallway ambulation if the patient is able (Freeman & Maley, 2013). The second postoperative day entails transfers thrice a day, ambulation 3-4 times a day, incentive spirometer, coughing, and deep breathing. Day 4-5 require the same activities as Day 2 except that ambulation is 4 times a day (Freeman & Maley, 2013). Even patients with mechanical circulatory support devices are supported to mobilise early.
However, there is controversy in relation to how early the early ambulation is. Evidence-based practice warrants that guidelines or protocols be based on available research evidence, clinical experience, and patient preferences rather than an arbitrary decision (Stevens, 2013). A focused question was developed to ascertain the state of evidence and what additional research needs to be done. The chosen population is adult post-cardiac surgery patients, and the intervention is early ambulation at less than 24 hours following extubation. It will be compared to early ambulation 24 hours post-extubation. The selected outcomes are wound status, early recovery, and vascular circulation. The clinical question is therefore stated as, “In post cardiac surgery patients, does early ambulation (less than 24 hours following extubation) contribute to early recovery, wound status, and vascular circulation compared with ambulation 24 hours after extubation?” A literature search and critique was done to answer this question.
Method of Literature Search
A structured search of the literature was conducted in the following databases: PubMed, Science Direct, CINAHL, Cochrane, and Medline. These key words guided the search: post-cardiac, post-heart, surgery, early, ambulation, mobilisation, less, than, more, than, 24 hours, after, extubation, recovery, wound, circulation. The strings were “post-cardiac or post-heart surgery and early ambulation or mobilisation and less than 24 hours after extubation” and “post-cardiac or post-heart surgery and early ambulation and more than 24 hours after extubation.” If the results are in the thousands, “recovery or wound or circulation” was added to the search strings.
The results were ranked according to relevance and limited to peer-reviewed journal articles in the English language published within the last 10 years or beginning in 2005. The titles were browsed and if deemed related to the clinical question, the abstract was reviewed to ensure its relevance to each element of the question. If filtered results exceeded 100, only the first 100 articles were considered for abstract review. The best articles in terms of relevance and research design were retrieved with greater preference placed on systematic reviews, randomised controlled trials (RCTs), quasi-experimental studies which are typically within a quality improvement framework, and cohort studies. If lacking, descriptive case studies were also considered.
Results of the Search
The combined search of the CINAHL and Medline databases with filters yielded 4,110 results. A review of the first 100 articles led to the retrieval of 3 articles. The search of PubMed lead to 121 results and the retrieval of 2 articles after duplicates were removed. In the Science Direct database were 225 results with the retrieval of one article after duplicate removal. One article was retrieved from the Cochrane Database bringing the total articles chosen for the review to 6. One is a systematic review, 3 were QI or non-QI quasi-experimental studies, one was a non-randomised trial, and one was a randomised prospective trial. There remains a paucity of research on the topic given the turnout of relevant articles.
Review of the Literature
Camp et al. (2009) conducted a quasi-experimental, single centre, before-and-after quality improvement (QI) study to determine if there were differences in outcomes between the intervention group that underwent early tracheal extubation, defined as extubation less than 6 hours following surgery, and the control group that underwent extubation more than 6 hours after surgery. A description of the new protocol that was implemented was described and included weaning the patient from the ventilator and incentive spirometry and early ambulation within the same day as extubation. Prior to this, ambulation was done the day after extubation. Staff adherence to the protocol was ensured through education and training. The defined outcomes were sepsis, pneumonia, length of stay in the ICU, hospital length of stay, reintubation, and ICU readmission. These outcomes are proxy indicators of patient recovery.
A large sample of 980 patients was in the post-intervention group while 1,231 participants were in the pre-intervention group (Camp et al., 2009). The sample size conferred 95% power to the study which is high. Surgeries included CABG, valve repair, or a combination of both. The results show that the post-intervention group had a lower rate of complications, namely pneumonia and sepsis, and reduced lengths of stay in the ICU and the hospital overall (Camp et al., 2009). Furthermore, there was a lower risk of reintubation and ICU readmission. The outcomes reflect speedier recovery when patients are extubated earlier and ambulated within 24 hours compared with delayed extubation and ambulation.
Murphy et al. (2007) conducted a single centre QI study with the same design as Camp et al. (2009) in a different sample of patients, namely those who underwent open repair of aneurysms in the thoracic aorta, albeit a smaller sample size of 60 patients. The protocol introduced involved fast-tracking the patient’s extubation and ambulation in order to meet the goal of reducing the length of hospital stay. Extubation and mobilization via sitting are performed within postoperative day zero. Again, this outcome is a proxy measure of recovery wherein shorter stays are associated with reduced complications including DVT and pulmonary embolism. The results also show a reduction in the median length of hospital stay from 9 days before protocol implementation down to 5 days after implementation.
Albeit not a QI study, Ahmed et al. (2006) also performed a single centre, before-and-after quasi-experimental study to ascertain the effect of early mobilisation on respiratory and cardiac parameters and ICU length of stay. Early mobilisation included repositioning the patient in bed, early ambulation through bed-to-chair transfers and walking, and chest physiotherapy. An even smaller sample was used – 20 patients for the pre-intervention group and 20 patients for the post-intervention group. All underwent open heart surgery. The results demonstrated earlier respiratory recovery in the early ambulation group with lower rates of dysrhythmias and atelectasis. Also noted in this group is a significantly shorter ICU length of stay implying earlier recovery from a critical status. However, no differences were found in relation to hemodynamic, oxygenation, and renal parameters.
Meanwhile, Kandasamy et al. (2013) conducted a non-randomised single centre study to compare the outcomes of ultra-fast track interventions and conventional treatment in a sample of 119 post-valve replacement surgery patients. The outcomes include recovery, ICU length of stay, and length of hospital stay. The ultra-fast track group was extubated less than 3 hours post-surgery while the conventional treatment group were extubated more than 3 hours post-surgery. Patients who were unstable were excluded from participation. The premedication, extubation, and other postoperative interventions that was standardised to all study participants was described.
Overall, the ultra-fast track group had shorter ICU and hospital lengths of stay with fewer hours on ventilation (Kandasamy et al., 2013). However, the conventional treatment group had a greater number of patients with pulmonary arterial hypertension (PAH) which could be a source of bias. Otherwise, the 2 groups are statistically similar in terms of demographic attributes. A multifaceted intervention that begins in the intraoperative period is seen to have contributed to the positive results. The use of titrated short-acting anaesthetics, maintenance of normothermia in the postoperative period, administration of appropriate analgaesics, early extubation, early ambulation, and promotion of the return of alimentary functions collectively contribute to early recovery (Kandasamy et al., 2013).
Hoque et al. (2011) used a randomised prospective trial design to determine the role of anaesthesia in early extubation and ambulation and the impact on respiratory and cardiovascular outcomes postoperatively. Forty adults who underwent cardiac surgery were allocated either to the total intravenous anaesthesia (TIVA) group or to conventional anaesthesia. Except for the choice of anaesthesia, all other treatment related factors were kept similar to reduce bias between the TIVA and conventional anaesthesia groups. The depressant effect of TIVA is shorter in duration than more long-acting conventional anaesthesia making it possible to perform early extubation and ambulation within 24 hours on postoperative day zero or day 1. On the other hand, overnight mechanical ventilation is often necessary when conventional anaesthetics were used. Extubation followed when the patient met the criteria for eye opening, muscle power, respiration, haemodynamic indicators, pain level, and presence or absence of bleeding. The results demonstrate better respiratory and haemodynamic performance following extubation and ambulation in the TIVA group compared with conventional anaesthesia. The outcome is an indirect indicator of recovery as it reduces the risk of reintubation and longer cardiac ICU stay.
In a systematic review, Zhu, Lee and Chee (2012) aimed to determine the impact of fast-track interventions in the post-cardiac surgery period on mortality as well as postsurgical complications and length of stay in the ICU and hospital. Comparison interventions were conventional or non-fast track care. Interventions were early extubation, early ambulation, and the use of low-dose opioids for general anaesthesia during the intraoperative period. Early extubation and ambulation typically occurred within postoperative day zero. Patient surgeries included CABG and valve replacement. Complications included wound infection and major bleeding.
Most of the 25 RCTs that met the inclusion criteria were of moderate quality meaning they had a moderate risk of bias (Zhu, Lee & Chee, 2012). The aggregate sample size of the studies was 4,118 patients, and most trial samples involved low- to moderate-risk patients. The trials demonstrated that there were no significant differences in rates of mortality and postoperative complications as well as length of hospital stay between patients who received fast-track and non-fast track interventions (Zhu, Lee & Chee, 2012). However, patients on fast-track care were noted to have shorter ICU stays indicative of lower risks for critical illness. The findings also show that fast-track care leads to similar outcomes as conventional care in low- to moderate-risk patients but at a lower cost.
The strength of the evidence is the integration of early ambulation within 24 hours following extubation into a multifaceted intervention such as fast-track protocols. This recognises the complex nature of post-cardiac surgery outcomes in that there are many factors that shape the clinical consequences. Hoque et al. (2011) and Kandasamy et al. (2013) highlight the safety of using anaesthetics that support early extubation and ambulation. Indeed, if the patient remains heavily sedated then extubation cannot be performed. Conversely, continued intubation may limit the patient’s ambulation. In addition, Kandasamy et al. (2013) underscore the need to prevent hypothermia and to promote alimentary functioning in addition to early extubation and ambulation if recovery is to be achieved. The quasi-experimental QI approach of Camp et al. (2009) and Murphy et al. (2007) enable a multifaceted approach through the implementation of protocols encompassing several different interventions. For instance, Camp et al. (2009) describe a protocol consisting of early extubation, chest physiotherapy, and ambulation.
There are limitations to the evidence, however. There is variation in the outcomes studied and includes mortality, ICU and/or hospital length of stay, recovery, respiratory and functional outcomes, bleeding, wound infection or healing, ventilator-associated pneumonia, and costs among others. Therefore, it is difficult to draw conclusions on effectiveness in relation to many of the outcomes when considering the entirety of the evidence. An exception is the systematic review of RCTs that lends support to reduced ICU length of stay (Zhu, Lee & Chee, 2012), a finding that is also supported by Ahmed et al. (2006), Camp et al. (2009), and Kandasamy et al. (2013).
Another limitation of the evidence is the conduct of studies in single centres. It may be difficult to generalise the findings of one hospital in Bangladesh as in the study by Hoque et al. (2011) or in Egypt as in the study by Ahmed et al. (2006) – countries with different health care systems than that of Australia. Small sample sizes also do not sufficiently reduce bias that would increase the reliability of the findings (Polit & Beck, 2012). The randomised trial by Hoque et al. (2011) employed 40 participants while the nonrandomised trial by Kandasamy et al. (2013) employed 119 patients. Only the study by Camp et al. (2009) was sufficiently powered in terms of sample size. These factors reduce the quality of the studies. Similarly, the systematic review by Zhu, Lee and Chee (2012) found that majority of the studies were of moderate quality.
Answer to the Clinical Question
The available evidence also does not provide adequate answers to the chosen clinical question. The outcome of early recovery was employed by only two studies – that by Ahmed et al. (2006) and Kandasamy et al. (2013). As such, ICU and hospital length of stay, ICU readmission, reintubation, and reductions in the risk of complications other than wound infection and circulation were considered as proxy or indirect measures of recovery such as in the studies by (2006), Camp et al. (2009), Hoque et al. (2011), and Murphy et al. (2007). The outcome of wound status was investigated only in the systematic review by Zhu, Lee and Chee (2012) while bleeding and haemodynamic parameters as clinical issues related to circulation were studied also in the systematic review and the randomised prospective study by Hoque et al. (2011).
All patients in the studies fit the clinical question as they were adults and post-CABG, post-heart valve repair or post-open thoracic aortic surgery. A shared characteristic across studies was that they have mild to moderate-risk for complications because high risk was a common exclusion criterion. However, there is a lack of direct comparison between early ambulation within and beyond 24 hours of extubation. That early ambulation was not the primary focus of all the studies except for Ahmed et al. (2006) is a contributory factor. If ambulation was done within the same time or day as extubation was mostly inferred from the description of interventions and outcomes. For instance, if extubation was done on postoperative day zero in ultra-fast track and ambulation is also done within the same day as in the study by Kandasamy et al. (2013) then it was assumed that early ambulation was within 24 hours of extubation.
The paucity of studies relevant to the research question warrants refinement of the question that will guide another literature search and appraisal. It is better for the time factor of early ambulation to be based not on the duration of time after extubation but on the duration of time after the surgical procedure given that fast-track protocols involve activities per postoperative day. It is also better to focus on more specific measures of recovery, circulation, and wound status – for instance length of stay or number of days before discharge to home, bleeding, and the incidence of wound infection. The inclusion of other better studied outcomes such as postoperative pneumonia can also be included. A proposed research question thus states, “Among adult post-cardiac surgery patients, does early ambulation beginning on the first postoperative day more effective in decreasing the length of stay and the incidence of bleeding, wound infection, and pneumonia compared with ambulation that begins later?” To ensure that more relevant studies turn up, it is also recommended that the date of publication be extended to include those published from 2000 to 2004.
Ahmed, H.H., Ibrahim, Y.M., El Soussi, A.H., & El Said, M.M. (2006). The effect of early activity on patients’ outcome after open heart surgery. Alexandria Journal of Anaesthesia and Intensive Care, 9(3), 34-43. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994021/
Camp, S.L., Stamou, S.C., Stiegel, R.M., Reames, M.K., Skipper, E.R., Madjarov, J., Lobdell, K.W. (2009). Quality improvement program increases early tracheal extubation rate and decreases pulmonary complications and resource utilization after cardiac surgery. Journal of Cardiac Surgery, 24, 414-423. doi: 10.1111/j.1540- 8191.2008.00783.x.
Freeman, R., & Maley, K. (2013). Mobilization of intensive care cardiac surgery patients on mechanical circulatory support. Critical Care Nursing Quarterly, 36(1), 73-88. doi: 10.1097/CNQ.0b013e31827532c3.
Hoque, A., Rahman, Z., Habib, A., Ali, A., Islam, A., & Rahman, A. (2011). Study on the effect of total intravenous anesthesia (TIVA) on the post-operative respiratory performance regarding early extubation after coronary artery bypass graft (CABG) surgery. Journal of the Bangladesh College of Physicians and Surgeons, 29, 3-9. doi: 10.3329/jbsp.v29i1.7164.
Kandasamy, A., Ramalingam, S.K., Simon, H.A., Arumugham, S., Reddy, B.D., & Krupananda, H. (2013). Ultra fast-tracking versus a conventional strategy in valve replacement surgery. Indian Journal of Anaesthesia, 57(3), 298-300. doi: 10.4103/0019-5049.115567.
Murphy, M.A. (2007). Fast track open aortic surgery: Reduced post-operative stay with a goal directed pathway. European Journal of Vascular and Endovascular Surgery, 34(3), 274-278. doi: http://dx.doi.org/10.1016/j.ejvs.2007.04.018.
Polit, D.F., & Beck, C.T. (2012). Nursing research: Generating and assessing evidence for nursing practice (9th ed.). Philadelphia, PA: Wolters Klowers Health/Lippincott Williams & Wilkins.
Zhu, F., Lee, A., & Chee, Y.E. (2012). Fast-track cardiac care for adult cardiac surgical patients. Cochrane Database of Systematic Reviews, 10(CD003587). doi: 10.1002/14651858.CD003587.pub2.