Postoperative day of surgery ambulation improves outcomes following lung resection: a multicenter prospective cohort study

Introduction

Enhanced recovery after surgery (ERAS) pathways are perioperative practices guidelines designed to decrease complications, length of stay, and hospital costs in surgical patients. Originally designed for colorectal surgery, there are now over 20 published ERAS guidelines across multiple surgical specialties (1,2). Guidelines for perioperative care after lung surgery from the ERAS Society thoracic surgery working group, in conjunction with the European Society of Thoracic Surgery (ESTS), were first formally published in 2019 (3). An integral tenant of ERAS is early postoperative mobilization within the first 24 hours of surgery (4). Despite a strong recommendation for early mobilization, the level of evidence for this particular recommendation in thoracic surgery is low (3). Previous systematic reviews examining the effect of early mobilization on post-operative outcomes following thoracic surgery have failed to demonstrate a conclusive benefit to early mobilization due to poor quality studies with conflicting results (5).

Moreover, there exists significant institutional variability in early mobilization protocols. Whereas some institutions encourage mobilization to a chair within the first 24 hours of surgery, others encourage ambulation (of varying pre-specified distances) within this timeframe. The specific impact of ambulation on the day of surgery after lung resection is therefore under-investigated. In one recent study, patients undergoing video-assisted thoracoscopic lobectomy were targeted for 250 feet of ambulation within 1 hour of extubation, which resulted in low rates of complications and a significantly decreased length of stay (6). However, this study was limited by its small sample size and single-institution nature.

The purpose of this study was to investigate the relationship between ambulation on the day of surgery after lung resection and post-operative outcomes. We hypothesized that patients who ambulated postoperatively on the day of surgery would experience fewer complications and have shorter hospital stays as compared to patients who did not. Elucidating this association could be useful as a predictor of a patient’s postoperative hospital course as well as a potential quality metric. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1183/rc).

Methods

Ethical oversight

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Colorado Multiple Institutional Review Board (COMIRB approval #20-3051) which oversees University of Colorado Anschutz Medical Campus and individual consent for this analysis was waived due to minimal risk to participants.

Data source and patient population

This was a multi-center, prospective cohort study from January 2019 to March 2023 within the University of Colorado Health System (UCHealth), a large healthcare system across the front range of Colorado. Thoracic surgery is performed at five of these hospitals. The main campus is a quaternary academic medical center linked to the University’s medical school and graduate medical education training programs including both general surgery residents and cardiothoracic surgery fellows; two of the campuses are medium-sized, academic-affiliated hospitals with a limited number of surgical trainees; and the remaining two campuses are medium-sized, private-practice hospitals without surgical trainees. Together, surgeons at these hospitals perform approximately 500 lung resections annually.

In May of 2021, a system-wide Thoracic ERAS protocol was implemented simultaneously across all hospitals. The design, implementation, initial compliance monitoring, and benefits in postoperative outcomes of this program has been previously described (7-9). Due to the universal implementation, patients at all sites received equivalent, standardized perioperative care bundles both in the preoperative and postoperative periods, including but not limited to a multimodal, opioid sparing, pain regimen. Patients undergoing lung resections (segmentectomy and lobectomy) were targeted for inclusion. Patients who were <18 years old, who underwent non-elective procedures, those who did not have ambulation information documented or who were non-ambulatory preoperatively were excluded. Data were extracted using automated pulls from discrete fields within the electronic healthcare record, and outcomes were obtained by linking Vizient data to individual patient encounters (Vizient, Inc., Irving, TX, USA). Patient data included demographics, comorbidities, operative information, postoperative day of first ambulation, and postoperative outcomes. Postoperative morbidities were defined using the graded using Clavien-Dindo Classification System (10).

Study design and statistical analysis

Patients were divided into two cohorts based on whether or not they ambulated postoperatively on the day of surgery. The primary outcome was overall morbidity. Secondary outcomes were rates of respiratory morbidity, cardiac morbidity, and infectious morbidities, as well as rates of individual postoperative complications, length of stay, chest tube duration, and hospital admission total cost. Unadjusted univariate comparison was performed using chi-square or Fisher’s exact test, where appropriate, for categorical comparisons and Mann-Whitney-U or independent t-test for continuous variables based on normality as assessed using the Shapiro Wilk test. Multivariable logistic regression controlling for age, body mass index (BMI), ERAS protocol inclusion, operative approach (e.g., robotic, thoracoscopic, or open), operative duration, and chest tube size was performed to identify the independent effect of ambulation on complication rates. Variables for risk-adjustment were selected based on univariate comparison, as above, where all variables with a P<0.25 were included in the model. Risk-adjusted rates are expressed as odds ratios (ORs) and 95% confidence intervals (95% CIs) for categorical variables and incidence rate ratios (IRRs) and 95% CI for continuous variables. Two-sided P values ≤0.05 were considered statistically significant. Statistical analyses were performed using SAS version 9.4 (SAS Inc., Cary, NC, USA).

Results

Cohort characteristics

A total of 1,063 patients met inclusion criteria. Of these, 7 (0.7%) patients were excluded for being unable to determine ambulation status from the electronic medical record, leaving 1,056 patients (99.3%) included in the analytic cohort. In the analytic cohort, 443 patients (42.0%) ambulated on the day of surgery, and 613 patients (58.0%) did not. Table 1 summarizes patient and operative characteristics, stratified by cohort. Patients who ambulated postoperatively on the day of surgery were slightly younger [median age 67.5 (61.0–73.0) vs. 69.0 (62.0–75.0) years, P=0.049]; however, there were no other differences in patient characteristics. Specifically, there were no differences in sex, BMI, comorbidity burden, or American Society of Anesthesiologists Physical Status Classification (ASA Class, all P>0.05). Regarding operative care characteristics, just under half of patients in each cohort were ERAS patients (47.2% vs. 42.6%, P=0.14), and the majority in each group underwent lobectomy (91.9% vs. 91.5%, P=0.84) for malignant indications (80.8% vs. 78.8%, P=0.47). Patients who ambulated on day of surgery were more likely to have undergone a thoracoscopic approach and less likely to have undergone an open approach (thoracoscopic: 47.0% vs. 38.0% and open: 4.7% vs. 10.4%, P<0.001). Additionally, patients who ambulated on the day of surgery had smaller chest tube size {median 24 [24–28] vs. 28 [24–28] French, P<0.001} and had a shorter operative duration [210.5 (174.0–260.0) vs. 239.0 (199.0–292.5) minutes, P<0.001].

Predictors of day of surgery ambulation

Risk-adjusted predictors of postoperative ambulation on the day of surgery are shown in Table 2.

Increasing age [0.99 (0.98–0.99)], open approach [compared to the thoracoscopic approach, 0.49 (0.27–0.89)] and increasing operative duration [0.99 (0.99–0.99)] were associated with significantly lower risk-adjusted odds of ambulating on the day of surgery. Interestingly, when compared to ASA Class IV, Class II was also associated with lower odds of day of surgery ambulation [0.45 (0.20–0.99)].

Postoperative outcomes

Table 3 shows the unadjusted rates and risk-adjusted OR and 95% CI for patients who ambulated on the day of surgery versus those who did not. Patients who ambulated on the day of surgery had significantly lower rates of overall morbidity (14.9% vs. 26.6%, P<0.001), any respiratory morbidity (12.6% vs. 22.2%, P<0.001), prolonged air leaks (8.6% vs. 16.0%, P=0.004), any cardiac morbidity (5.0% vs. 8.6%, P=0.02), cardiac arrhythmias (4.7% vs. 8.5%, P=0.02), any infectious morbidity (1.8% vs. 4.9%, P=0.008), surgical site infections (0.0% vs. 1.1%, P=0.046), and lower rates of bleeding complications (0.2% vs. 2.6%, P=0.002). There were no difference in rates of major vs. minor complications by group (P=0.23). Additionally, patients who ambulated had significantly lower opioid use [median 89.0 vs. 119.0 morphine equivalent daily dose (MEDD), P<0.001], shorter length of stay (median 3.0 vs. 4.0 days, P<0.001), shorter chest tube duration (median 2.0 vs. 3.0 days, P<0.001), and lower total hospital cost (median $17,613 vs. $19,812, P<0.001).

After controlling for potential confounders, patients who ambulated day of surgery had lower risk-adjusted odds of any morbidity (OR 0.70, 95% CI: 0.49–0.99), less opioid consumption (IRR 0.75, 95% CI: 0.59–0.95), and had shorter length of stay (IRR 0.59, 95% CI: 0.47–0.75) and chest tube duration (IRR 0.62, 95% CI: 0.49–0.79).

Discussion

In this prospective cohort of 1,056 patients who underwent lung resection, patients who ambulated postoperatively on the day of surgery had fewer respiratory, cardiac, and infectious complications. Following risk-adjustment, these patients had lower rates of overall morbidity, less opioid consumption, and shorter chest tube duration and length of stay. Day of surgery ambulation is an excellent quality metric, associated with avoidance of postoperative complications, and may independently improve outcomes after lung resection.

There is strong evidence for the benefit of early postoperative ambulation across several non-thoracic disciplines (11-14). Immobilization has been shown to increase insulin resistance, impair gastrointestinal function, increase risk of thromboembolic events and contributes to cardiovascular, respiratory, and musculoskeletal deconditioning (15-17). As such, early ambulation is a common component in ERAS protocols. To date, the majority of studies in the thoracic literature comment on early ambulation as a component of the protocol but focus on the effect of ERAS as a whole, rather than the independent effect of ambulation. The heterogeneity of thoracic ERAS protocols, and their mobilization components, further limits interpretation of the effect of early ambulation. Some institutions simply encourage mobilization to a chair on the operative or first-post operative day, whereas others have ambulation, without a specific distance, as a goal; still others encourage more aggressive approaches including ambulation within 1 hour of extubation (6,18-20). While these studies have suggested improved outcomes with adherence to ERAS, and by virtue of this, early ambulation, they are limited by their lack of control for all of the other confounding multidisciplinary components of ERAS. We too have demonstrated the benefits of a thoracic ERAS protocol at our diverse, multihospital system (9) based off the 2019 ESTS and ERAS Society guidelines (3). However, following our successful implementation (7,8), we have been interested in how compliance to various components of ERAS independently affects outcomes. In this study, we have demonstrated an independent association between improved outcomes and early postoperative ambulation.

Prior to our work, the majority of direct early ambulation studies in the thoracic literature have focused on the video-assisted thoracic surgery (VATS) approach. Ding et al. [2023] examined a cohort of 101 VATS patients who ambulated within 24 hours of completion of surgery and demonstrated significantly reduced duration of chest tubes, time to return to bowel function, and length of hospital stay, as well as decreased pain and overall morbidity (21). In a study of 304 VATS thoracic ERAS patients, 61.5% ambulated within one hour of surgery, and while the independent effect of ambulation was not directly assessed, these patients on the ERAS pathway had shorter length of stay and lower rates of pneumonia and atrial fibrillation (6). These studies are limited by either their small sample or single institution design focusing on one approach, or lack of control for ERAS status and confounders. Our data add to the growing body of literature supporting early ambulation in thoracic patients and address some of the previous studies’ limitations, including expansion to a diverse multi-hospital system, examination of varying approaches including open, VATS and robotic-assisted thoracic surgery, and correction for ERAS status indicating that these observed improved outcomes are independently associated with early ambulation.

Historically, there have been concerns about early ambulation. However, studies have demonstrated the safety and efficacy of early ambulation, including a comparison study that showed no difference in chest tube output, vital signs, or pain scores after walking when comparing early ambulators to non-early ambulators (22,23). Studies have also shown no significant increase in rates of prolonged air leak, with early ambulators having a prolonged air leak rate of 12.35%, which is consistent with existing literature regarding non-ambulators citing an incidence ranging between 5–25% (22,23). Our study builds on these findings, actually demonstrating a lower incidence of prolonged air leak in our early ambulation cohort on unadjusted analysis. Beyond explicit safety, there are concerns regarding barriers to ambulation. Patient and provider consideration of whether to ambulate early post-surgery is a complex issue, involving both physical, staffing, and psychological barriers (24). We found increasing age, use of the open approach, and increased operative duration to be independent negative predictors of early ambulation. While we did not directly assess patient reported barriers to ambulation in this study, prior studies in the colorectal ERAS literature have examined barriers to early postoperative ambulation Including poor pain control, nausea, and dizziness (25). Additionally, patients can be burdened by necessities of care including intravenous lines, urinary catheters (which we do not routinely place), drainage tubes, and cardiopulmonary monitoring equipment such as pulse oximeters and electrocardiograph telemetry leads.

At our institution, early ambulation is often accompanied by trained mobility techs or medical assistants, and we recommend that patients be monitored during ambulation including mobile pulse oximetry and telemetry. As ambulation requires energy expenditure, and physical activity thresholds vary amongst individuals, mobilization activities including early ambulation should ultimately be individualized (24).

This study should be interpreted in the context of some important limitations. First, while this was a multi-site study, it occurred under the umbrella of a single healthcare system in one geographic location, which may not be generalizable. Second, while risk-adjustment showed that day of surgery ambulation was independently associated with improved outcomes, there remains the possibility of unknown confounders that were not adjusted for in our analysis. This includes, but is not limited to, lack of risk-adjustment for a patient’s baseline exercise capacity. Third, time of day of the operation was not included in the dataset, and the time of completion of the operation almost certainly impacts whether patients ambulate on the day of surgery after the conclusion of their operation. The duration and distance of walking was not reported, and 0.7% of prospectively enrolled patients were excluded due to lack of documentation of ambulation status. As such, patients who ambulated a short distance may not have benefited as much as patients who walked further, consequently diluting the impact of walking on postoperative outcome, and due to exclusions in a prospective cohort, a bias may have been introduced. Further work by our group exploring the effect of ambulation with defined duration and distance is ongoing as part of our iterative revision of our ERAS pathway, as well as specifically evaluate the subgroups of patients including those with malignant versus non-malignant indications. Finally, although early ambulation was associated with decreased complications, it is unclear if walking led to decreased risk of complications, or if this observation was the result of having fewer comorbidities and complications.

Conclusions

Patients who ambulated postoperatively on the day of lung resection had lower risk-adjusted odds of any morbidity, shorter chest tube duration and length of stay, and less opioid consumption during their hospitalization than patients who did not ambulate the day of surgery. Day of surgery ambulation is at least a useful predictor of postoperative course and quality metric for patients undergoing lung resection. However, ambulation on the day of surgery may also contribute to lower complication rates and shorter hospitalization. Future studies could potentially examine the effect of early mobilization bundles on postoperative complication rates to delineate whether this is a quality metric or contributes to improved outcomes.

Acknowledgments

This work is being considered for presentation at the 20^th Annual Academic Surgical Congress in Las Vegas, NV, February 11–13, 2025.

Funding: This work was supported by the National Institutes of Health (NIH), under Ruth L. Kirschstein National Research Service Award T32CA17468. This presentation’s contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1183/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1183/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1183/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-1183/coif). J.D.M. reports that he consults for Intuitive Surgical, Inc. R.A.M. reports that he consults for Medtronic, Inc. C.M.S. receives salary support, in part, by the National Institutes of Health, under Ruth L. Kirschstein National Research Service Award T32CA17468. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Colorado Multiple Institutional Review Board (COMIRB approval #20-3051) which oversees University of Colorado Anschutz Medical Campus and individual consent for this analysis was waived due to minimal risk to participants.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. ERAS® Society. Available online: https://erassociety.org/guidelines/
2. Ljungqvist O, Scott M, Fearon KC. Enhanced Recovery After Surgery: A Review. JAMA Surg 2017;152:292-8. [Crossref] [PubMed]
3. Batchelor TJP, Rasburn NJ, Abdelnour-Berchtold E, et al. Guidelines for enhanced recovery after lung surgery: recommendations of the Enhanced Recovery After Surgery (ERAS®) Society and the European Society of Thoracic Surgeons (ESTS). Eur J Cardiothorac Surg 2019;55:91-115. [Crossref] [PubMed]
4. Tazreean R, Nelson G, Twomey R. Early mobilization in enhanced recovery after surgery pathways: current evidence and recent advancements. J Comp Eff Res 2022;11:121-9. [Crossref] [PubMed]
5. Castelino T, Fiore JF Jr, Niculiseanu P, et al. The effect of early mobilization protocols on postoperative outcomes following abdominal and thoracic surgery: A systematic review. Surgery 2016;159:991-1003. [Crossref] [PubMed]
6. Khandhar SJ, Schatz CL, Collins DT, et al. Thoracic enhanced recovery with ambulation after surgery: a 6-year experience. Eur J Cardiothorac Surg 2018;53:1192-8. [Crossref] [PubMed]
7. Dyas AR, Kelleher AD, Erickson CJ, et al. Development of a universal thoracic enhanced recover after surgery protocol for implementation across a diverse multi-hospital health system. J Thorac Dis 2022;14:2855-63. [Crossref] [PubMed]
8. Dyas AR, Kelleher AD, Cumbler EU, et al. Quality Review Committee Audit Improves Thoracic Enhanced Recovery After Surgery Protocol Compliance. J Surg Res 2024;293:144-51. [Crossref] [PubMed]
9. Dyas AR, Stuart CM, Bronsert MR, et al. Anatomic Lung Resection Outcomes After Implementation of a Universal Thoracic ERAS Protocol Across a Diverse Health Care System. Ann Surg 2024;279:1062-9. [Crossref] [PubMed]
10. Clavien PA, Barkun J, de Oliveira ML, et al. The Clavien-Dindo classification of surgical complications: five-year experience. Ann Surg 2009;250:187-96. [Crossref] [PubMed]
11. Wainwright TW, Gill M, McDonald DA, et al. Consensus statement for perioperative care in total hip replacement and total knee replacement surgery: Enhanced Recovery After Surgery (ERAS®) Society recommendations. Acta Orthop 2020;91:3-19. [Crossref] [PubMed]
12. Temple-Oberle C, Shea-Budgell MA, Tan M, et al. Consensus Review of Optimal Perioperative Care in Breast Reconstruction: Enhanced Recovery after Surgery (ERAS) Society Recommendations. Plast Reconstr Surg 2017;139:1056e-71e. [Crossref] [PubMed]
13. Gustafsson UO, Scott MJ, Hubner M, et al. Guidelines for Perioperative Care in Elective Colorectal Surgery: Enhanced Recovery After Surgery (ERAS®) Society Recommendations: 2018. World J Surg 2019;43:659-95. [Crossref] [PubMed]
14. Dort JC, Farwell DG, Findlay M, et al. Optimal Perioperative Care in Major Head and Neck Cancer Surgery With Free Flap Reconstruction: A Consensus Review and Recommendations From the Enhanced Recovery After Surgery Society. JAMA Otolaryngol Head Neck Surg 2017;143:292-303. [Crossref] [PubMed]
15. Lavie CJ, Ozemek C, Carbone S, et al. Sedentary Behavior, Exercise, and Cardiovascular Health. Circ Res 2019;124:799-815. [Crossref] [PubMed]
16. Crossland H, Skirrow S, Puthucheary ZA, et al. The impact of immobilisation and inflammation on the regulation of muscle mass and insulin resistance: different routes to similar end-points. J Physiol 2019;597:1259-70. [Crossref] [PubMed]
17. Dittmer DK, Teasell R. Complications of immobilization and bed rest. Part 1: Musculoskeletal and cardiovascular complications. Can Fam Physician 1993;39:1428-32, 1435-7.
18. Gonfiotti A, Viggiano D, Voltolini L, et al. Enhanced recovery after surgery and video-assisted thoracic surgery lobectomy: the Italian VATS Group surgical protocol. J Thorac Dis 2018;10:S564-70. [Crossref] [PubMed]
19. Hubert J, Bourdages-Pageau E, Garneau CAP, et al. Enhanced recovery pathways in thoracic surgery: the Quebec experience. J Thorac Dis 2018;10:S583-90. [Crossref] [PubMed]
20. Brunelli A, Thomas C, Dinesh P, et al. Enhanced recovery pathway versus standard care in patients undergoing video-assisted thoracoscopic lobectomy. J Thorac Cardiovasc Surg 2017;154:2084-90. [Crossref] [PubMed]
21. Ding X, Zhang H, Liu H. Early ambulation and postoperative recovery of patients with lung cancer under thoracoscopic surgery-an observational study. J Cardiothorac Surg 2023;18:136. [Crossref] [PubMed]
22. Kaneda H, Saito Y, Okamoto M, et al. Early postoperative mobilization with walking at 4 hours after lobectomy in lung cancer patients. Gen Thorac Cardiovasc Surg 2007;55:493-8. [Crossref] [PubMed]
23. Mueller MR, Marzluf BA. The anticipation and management of air leaks and residual spaces post lung resection. J Thorac Dis 2014;6:271-84. [Crossref] [PubMed]
24. Amidei C. Mobilisation in critical care: a concept analysis. Intensive Crit Care Nurs 2012;28:73-81. [Crossref] [PubMed]
25. Thörn RW, Stepniewski J, Hjelmqvist H, et al. Supervised Immediate Postoperative Mobilization After Elective Colorectal Surgery: A Feasibility Study. World J Surg 2022;46:34-42. [Crossref] [PubMed]