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Safety and outcomes of performing laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy at an ambulatory site of a tertiary care hospital in Ontario

Background: In Ontario, bariatric surgery is publicly funded and is performed only in accredited tertiary care hospitals. The purpose of our study was to report on the safety and outcomes of performing bariatric surgery at an ambulatory site of a tertiary care hospital in southern Ontario. Methods: We conducted a retrospective cohort study of all adult (age ≥ 18 yr) patients who underwent primary laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) at the ambulatory site of our tertiary care hospital between September 2016 and August 2018. The 2 sites are 1.4 km apart. Patient demographic characteristics, duration of surgery, intraoperative and 90-day postoperative complications, number of transfers and readmission to the tertiary care hospital, and emergency department visits were collected. Results: A total of 314 patients (285 women [90.8%] and 29 men [9.2%] with a mean age of 41.8 yr [standard deviation (SD) 8.9 yr]) underwent surgery: LRYGB in 295 cases (93.9%) and LSG in 19 (6.0%). The mean body mass index was 45.3 (SD 5.1), the median American Society of Anesthesiologists score was 3 (range 2–4), and the median Edmonton Obesity Staging System score was 2 (range 0–4). The mean operative time was 119.8 (SD 23.1) minutes for LRYGB and 96.2 (SD 22.0) minutes for LSG, and the mean length of stay was 2.1 (SD 0.6) days and 2.1 (SD 0.2) days, respectively. Thirteen patients (4.1%) required transfer to the tertiary care hospital for a postoperative complication. Of 312 patients, 29 (9.3%) presented to emergency department within 90 days after surgery, and 8 (2.6%) required readmission to hospital; no deaths were reported. Conclusion: The findings suggest that LRYGB and LSG can be performed safely at an ambulatory site of a tertiary care hospital. However, caution should be exercised in performing these procedures at an ambulatory site without a tertiary care hospital affiliation, as patients may require urgent transfer for a serious postoperative complication.

besity is a chronic disease associated with severe comorbidities that entails a reduced quality of life, increased health care costs and reduced life expectancy. 1,2 In 2018, an estimated 7.3 million Canadian adults had class I obesity or greater (body mass index [BMI] ≥ 30.0), a figure that has been increasing steadily over time. 3 More worrisome are the continued increases seen in the prevalence of class II (BMI 35.0-39.9) and class III (BMI ≥ 40.0) obesity in Canada, from 1.207 million people in 2009 to 1.774 million in 2017. 3 In Canada, there are regional variations in the rates of obesity, with Ontario reporting 26.1% of the population with class I obesity or higher in 2018. 4,5 Bariatric surgery provides durable, long-term weight loss and amelioration of obesity-related comorbidities. 6 It is currently available in most provinces across Canada. However, regional volumes vary considerably, which leads to considerable disparities between provinces. 3 In Ontario, all publicly funded bariatric operations are performed at Bariatric Centres of Excellence accredited by the Ontario Bariatric Network. At a minimum, accreditation requires 1) a full acute care and inpatient facility; 2) intensive care unit availability; 3) 24-hour emergency department and surgical coverage; 4) oximetry beds for postoperative care, with availability of a respiratory technician; 5) at least 2 laparoscopic bariatric surgeons, with each surgeon performing a minimum of 50 cases per year; 6) a minimum volume of 120 bariatric cases per year; 7) a multidisciplinary clinic for preoperative and postoperative care; 8) medical bariatric support for clinic and inpatient care; and 9) psychiatry support for pre-and postoperative assessment if necessary. As such, all publicly funded bariatric surgery in Ontario is performed at tertiary care hospitals. Performing bariatric surgery in patients at low or intermediate risk at ambulatory sites of tertiary care hospitals may create additional capacity within the health care system to increase the annual number of bariatric operations performed in Canada. 7 However, the safety of this health care delivery model has yet to be extensively investigated.
The purpose of the present study was to report on patients' outcomes, morbidity and use of health care services after laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) performed at the ambulatory site of a tertiary care hospital in Ontario.

Study setting and design
In 2016, the bariatric surgery program at the Kingston Health Sciences Centre (Kingston, Ontario, Canada) was accredited to perform bariatric surgery at both a tertiary care hospital and an ambulatory site of the tertiary care hospital. The 2 sites are 1.4 km apart. The ambulatory site is open from Monday to Friday, and patients undergoing bariatric surgery can stay for up to 48 hours at the ambulatory site. As there is no after-hours access to imaging, operating rooms, intensive care unit or medical consultation services at the ambulatory site, the Kingston Health Sciences Centre designed a strict protocol to facilitate urgent transfer to the tertiary care hospital for postoperative complications.
Our program has 2 surgeons, 1 fellowship-trained bariatric surgeon (B.Z.) and 1 experienced minimally invasive general surgeon without bariatric fellowship training (D.I.R.). The second surgeon was proctored by the fellowship-trained bariatric surgeon during the first 50 bariatric cases to ensure that he had passed the initial learning curve. 8 Surgery residents, bariatric surgery fellows and anesthesia residents participate in the LRYGB and LSG cases performed at the ambulatory site. A selected group of anesthesiologists and nurses who have a special interest in bariatric surgery cases provide the majority of perioperative and intraoperative care.
We conducted a retrospective cohort study of all adult (age ≥ 18 yr) patients who underwent LRYGB or LSG at the ambulatory site of the tertiary care hospital between Sept. 1, 2016, and Aug. 31, 2018. Ethics approval was obtained from Queen's University Health Sciences and Affiliated Teaching Hospitals Research Ethics Board (SURG-452-18).

Inclusion and exclusion criteria
Patients with the following characteristics were not eligible to undergo surgery at the ambulatory site: age younger than 18 years; history of prior bariatric surgery, revision or conversion bariatric surgery; untreated obstructive sleep apnea; prior history of venous thromboembolism; Obesity Surgery Mortality Risk Score 4 or higher; or BMI greater than 55. l'hôpital de soins tertiaires pour une complication postopératoire. Sur 312 patients, 29 (9,3 %) ont consulté aux urgences dans les 90 jours suivant leur chirurgie et 8 (2,6 %) ont dû être réhospitalisés; aucun décès n'a été signalé.
Patients undergoing concurrent hiatus hernia repair, cholecystectomy, or ventral or umbilical hernia repair were included in our cohort.

Operative technique
We perform LRYGB as an antecolic, antegastric configuration with a 50-100 cm biliopancreatic limb, a 100-150 cm Roux limb and a 25 mm circular stapled gastro jejunal anastomosis. We routinely close jejunojejunostomy mesenteric defects and Petersen's space, and perform intraoperative gastroscopy for an air leak test of the gastrojejunal anastomosis.
We perform LSG using a 40 F bougie to size the sleeve and perform routine intraoperative gastroscopy for an air leak test.

Perioperative care
Patients receive multimodal analgesia perioperatively, including oral celecoxib and acetaminophen prophylaxis preoperatively, local analgesia injection into the subcutaneous tissues around port sites intraoperatively, and acetaminophen and hydromorphone elixir (as needed) for pain postoperatively. We administer triple prophylaxis for postoperative nausea and vomiting (dexamethasone, ondan setron and metoclopramide given intravenously) intraoperatively, followed by intravenous administration of metoclopramide every 8 hours for 3 doses. Nasogastric tubes and drains are not used, and patients are allowed to drink liquids and take oral medications starting 2 hours after the procedure.
Patients are assessed daily by the attending surgeon. Those whose postoperative course deviates from expected are reassessed by the attending surgeon, who ultimately makes the decision regarding transfer to the tertiary care hospital.

Transfer criteria
As per preprinted orders, surgeons are alerted by nursing staff if patients' vital signs fall outside of normal parameters or if patients experience an unusual postoperative course (e.g., increased pain, nausea or vomiting, abdominal distension, melena or hematemesis). In such cases, a surgeon assesses the patient and decides whether the patient should be transferred to the tertiary care hospital. Examples of indications for transfer include sustained sinus tachycardia, ongoing nausea and vomiting, gastrointestinal bleeding, hypoxemia requiring supplemental oxygen on the day of planned discharge, severe abdominal pain and postoperative bleeding. Given the newness of our program, we had a fairly low threshold to transfer patients to the tertiary care hospital.

Demographic data
We collected the following patient demographic data from the patients' electronic medical records: age, sex, preoperative BMI, American Society of Anesthesiologists score, Edmonton Obesity Staging System score, prior abdominal surgery and obesity-related comorbidities.

Outcomes
Outcomes of interest included duration of surgery (from start of anesthesia to end of anesthesia, in minutes), intraoperative complications, length of hospital stay (in days), requirement for transfer to the tertiary care centre, reasons for transfer and complications arising within the first 90 days after surgery. This information was obtained from the patients' electronic medical records. We also collected data on use of health care services, including emergency department visits and unscheduled visits to a family physician's office, within 90 days of surgery from postoperative visit follow-up forms and through review of our hospital electronic medical records.

Statistical analysis
We report descriptive statistics as mean and standard deviation (SD) for continuous variables, and median and range for categorical variables. There were 11 intraoperative complications (3.5%) ( Table 3).

Results
Thirteen patients (4.1%) required transfer to the tertiary care hospital (Table 4). Their average age was 45.9 (SD 8.9) years, their average BMI was 46.9 (SD 4.8), and 5 patients (38%) were male. There were no significant differences in age (p = 0.1) or BMI (p = 0.3) between patients who were transferred and those who were not; however, the proportion of male patients was significantly higher in the group that was transferred (38% v. 9%; p < 0.01).
Intra-and postoperative complications that necessitated transfer to the tertiary care hospital are reported in Table 5. Five patients were taken back to the operating room for laparoscopic exploration. The findings included bleeding (in 2 patients) and complication at jejunojejunostomy (2 patients); in 1 case, the findings were negative. Five patients required supportive care, with blood transfusion in 3 patients and with supplemental oxygen in 2. The remaining 3 patients required observation without additional medical intervention.
Two patients (0.6%) were lost to follow-up in the first 30 days. Among the remaining 312 patients, there were 38 (12.2%) unscheduled contacts with the health care system within 90 days of surgery. These included 29 (9.3%) visits to the emergency department, 8 of which required hospital admission, and 1 visit to the family doctor.

discussion
In this retrospective cohort study reviewing our 2-year experience of performing publicly funded bariatric surgery in patients at low or moderate risk at an ambulatory site of a tertiary care hospital, more than 90% of procedures were LRYGB, with some patients having a concurrent hiatus hernia repair or cholecystectomy or both. Intraoperative complications were seen in 3.5% of patients, and 4.1% of patients required transfer from the ambulatory site to the tertiary care hospital for a postoperative complication. Overall, 9.3% of patients presented to the emergency department within 90 days of surgery, and 2.6% required readmission to hospital.
These positive results provide important information to stakeholders, including bariatric surgeons, obesity specialists and policy-makers. By demonstrating safety and  Prior history of excessive drinking 55 (17.5) effectiveness, this ambulatory bariatric surgery model may create additional capacity for bariatric surgery in Canada.
As well, the model may help to reduce regional disparities in access to bariatric surgery across Canada. 3,9,10 The safety of performing LRYGB, LSG and laparoscopic adjustable gastric banding in a secondary health care centre in Quebec was reported by Christou 7 in 2013. He described 676 publicly funded cases (558 LRYGB, 29 LSG and 89 gastric band) performed in a 17-bed private hospital in Montréal with a dedicated "service corridor" to a tertiary care hospital. The reported 30-day complication rate was 7.5%, and 1.2% of patients required transfer to a tertiary care hospital. Our 90-day postoperative complication rate, 8.3%, is similar to that reported by Christou, 7 but our transfer rate, 4.1%, appears to be higher. This may be explained by the higher proportion of LRYGB cases performed at our institution, which are often associated with a higher perioperative complication rate compared to LSG or adjustable gastric banding. 11 In addition, the threshold to transfer may have differed between the centres.
Our practice is to discharge patients after LRYGB or LSG on postoperative day 1 or 2. This is in agreement with an analysis of data from the Bariatric Outcomes Longitudinal Database, which showed an increased risk of 30-day mortality and serious complications in patients undergoing LRYGB with lengths of stay shorter than 23 hours. 12 It is also in agreement with analyses of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program national database, which showed increased morbidity and mortality for same-day discharge for LSG 13 and LRYGB. 14

E43
There are several advantages to performing bariatric surgery in ambulatory sites of tertiary care hospitals. The cost of performing surgery in an ambulatory site has been reported to be lower than performing the same surgery in a tertiary care hospital for complex lower extremity orthopedic surgery, 15 cervical discectomy 16 and surgical reversal of sterilization (microsurgical tubal anastomosis). 17 We hypothesize that the cost of performing bariatric surgery in an ambulatory site may be lower than that in a tertiary hospital; however, further research with appropriate matching of patient characteristics and case difficulty is required to confirm this hypothesis.
Operating room efficiency at an ambulatory site is often higher than at a tertiary care hospital. In our institution, this difference in efficiency translates into 1 fewer bariatric surgery case completed per day at the tertiary care hospital versus the ambulatory site. Similar results regarding operating room efficiency have been reported in the urology 18 and anesthesia 19 literature. Xu and colleagues 18 examined ureteroscopy procedures performed by a single surgeon at an ambulatory centre versus a tertiary care academic medical centre for patients assessed as American Society of Anesthesiologists class 1 or 2. The authors controlled for patient, case complexity and case order characteristics. They used multiple linear regressions to evaluate differences in total, preoperative, operative and postoperative times, delays and operating room turnaround times between the 2 facilities and found consistently shorter mean times at the ambulatory centre than at the tertiary care centre.
Some of the operating room efficiencies observed at an ambulatory site may be due to lack of trainees for both the surgery team and the anesthesia team. Urman and colleagues 19 compared day surgery operating room efficiency for anesthesiologists working alone and those working with residents to determine whether trainees affect operating room efficiency significantly. They showed that, compared to the solo anesthesiologist group, anesthesiologists working with residents had significantly longer induction, emergence and total anesthesia-controlled times.
We plan to further investigate which factors contribute to the improved operating room efficiencies for bariatric surgery performed at the ambulatory site as compared to the tertiary care hospital.

Limitations
The proportion of patients presenting for unscheduled visits to the emergency department or their family doctor within 90 days of surgery may be an underestimation of the true proportion, as there is the potential for recall bias when patients report these events. We attempted to mitigate this bias by examining our hospital's electronic medical record for all patients in our cohort to document visits to the emergency department. However, the bariatric program's large catchment area limited the ability to capture all possible emergency visits.
Our rates of peri-and postoperative complications represent data for the first 2 years of the bariatric surgery program at our institution. Although our complication rates are in agreement with published rates from the United States 20 and Canada, 21 we would expect a reduction in rates as the program and surgeon experience continue to mature. 22 The operative times reported in our study include concurrent procedures (hiatus hernia repair, cholecystectomy, umbilical hernia repair) that were done in conjunction with the primary bariatric surgery. As such, the mean operative times for primary LRYGB and LSG without a concurrent operation are expected to be shorter than our reported times.
Finally, our results may not be generalizable to other bariatric programs, with different distances and traffic patterns between the tertiary care hospital and its ambulatory site. Our 2 hospital sites are 1.4 km apart, with minimal traffic along the transfer route at any time of day. As such, our results may not be applicable to programs with greater distances between hospitals and longer transfer times.
conclusion Laparoscopic Roux-en-Y gastric bypass and LSG can be performed safely in patients at low to moderate risk at an ambulatory site of a tertiary care hospital with an overnight stay. However, caution should be exercised in performing these procedures at an ambulatory site without a tertiary care hospital affiliation, as patients may require urgent transfer for a serious postoperative complication.