Although laparoscopic sleeve gastrectomy in morbidly obese patients has become a routine outpatient procedure in Europe and the USA [6, 7], all our patients received perioperative treatment in the hospital for around 5 days. This difference has been considered to be due to the medical insurance systems and the consciousness of Japanese patients and their families with respect to surgical treatment. However, the most important factor is the smaller number of patients undergoing bariatric surgery in Japan. In our institution, surgically obese patients are hospitalized on the day before the operation and enter the intensive care unit soon after surgery until postoperative day (POD) 1. These patients receive walking rehabilitation after POD 1 in a general ward, and they are subsequently discharged from the hospital if they have no complications due to the operation. One patient in group L complained of chest pain on POD 2, which we suspected to be due to ischemic heart disease or pulmonary arterial emboli, and initiated heparin infusion. His complaint resolved after POD 3, and there were no abnormal findings on echocardiography and/or blood examinations. Although no other severe complications were observed in either group, a prolonged poor oral intake was observed in five patients of group L. The principal factor related to a delayed discharge was slow progress with walk rehabilitation independently due to pain at the operated site and/or muscle weakness [8,9,10].
In the present study, we assessed the cause of a longer hospital stay from the perspective of anesthesia management. Although the odds ratios were not particularly high, prolonged duration of anesthesia affected longer hospital stay (Table 3, p < 0.05). Moreover, operation time, blood loss, and infusion volume were correlated with anesthesia time (p < 0.05). That means the longer surgical procedure resulted in increasing of blood loss and infused fluid volume; consequently, tissue edema including gastro-intestinal tract was induced [11, 12]. Figure 1 presents the time trend of surgical and anesthetic time in our hospital. Since both durations tended to be shorter, the length of hospital stay could be stable.
There have been reports that the risk of perioperative complications is increased in patients with BMI ≥ 50 [7, 10]. In our cohort, the proportions of patients with BMI over 50 were 12% in group S and 30% in group L. That difference was not statistically significant but was slightly superior in group L (Table 4).
On the other hand, obstructive sleep apnea (OSA) has become one of the important risks for anesthetic management, especially in bariatric surgery, where the prevalence of OSA is higher and the incidences of postoperative intubation and ventilation are increased [7, 9]. In our study, the proportion of patients with the complaint of OSA was greater in group S compared with group L. Accordingly, while most of the patients with OSA have not been diagnosed preoperatively, all of our patients consulted a doctor in the department of sleep medicine prior to undergoing bariatric surgery. Therefore, postoperative complications with obstructive respiratory disorder were predicted and prevented by treatment for OSA, e.g., CPAP device.
The most important findings in this study was that longer duration of anesthesia affected the duration of postoperative hospital stay in morbidly obese patients. In addition, patients with BMI ≥ 50 may experience longer durations of hospitalization after surgery.
This retrospective study has some inherent limitations. Firstly, the number of patients was small, and the numbers in each of the groups were different. Secondly, the patients were divided into two groups based upon the duration of postoperative hospital relative to the ordinary date of discharge in our institution. However, it was unknown whether our classification is adequate or not. Thirdly, we have not analyzed the detailed anesthesia methods or postoperative analgesia.
The number of morbidly obese Japanese patients who undergo laparoscopic sleeve gastrectomy remains small. Therefore, further analyses of Japanese obese patients will be necessary in the future.