Objectives: Living-donor liver transplant has become a viable option and an important source of hepatic grafts. The goal of this study is to establish postoperative pulmonary complications of liver donation surgery in our center.

Materials and Methods: Data from 188 subjects (median age, 33.7 ± 8.4 y; male/female, 51.1%/48.9%) who had liver donation surgery from 1988 to 2013 were analyzed retrospectively. Patient demographic and clinical features were recorded. Postoperative complications and the correlation of risk factors for postoperative pulmonary com­plications were investigated.

Results: The incidence of early postoperative complications was 17% (n = 32), and 16 of these patients had postoperative pulmonary com­plications (8.5%); 2 of the postoperative pulmonary complications were detected on the day of surgery and the other 14 complications were observed between the second and seventh day after surgery. Most postoperative pulmonary complications were minor complications including atelectasis, pleural effusion, and pneumonia. There was 1 major postoperative pulmonary complication: pulmonary embolism that occurred on the fourth day after surgery in 1 patient. Late pulmonary complications also were reviewed and no late postoperative pulmonary complications were observed. Therewas no significant difference in early and late postoperative pulmonary complications between ex-smokers and smokers. Postoperative atelectasis was significantly higher in patients with body mass index ≤ 20 kg/m² than patients with body mass index > 21 kg/m² (P = .027). In our study population, no postoperative mortality was recorded.

Conclusions: We believe that preoperative weight reduction strategies and early mobilization with postoperative respiratory physiotherapy could be important factors to reduce postoperative pulmonary complications in liver donors.

Key words : Atelectasis, End-stage liver disease, Pleural effusion, Pneumonia, Transplant

Introduction

Living-donor liver transplant (LDLT) has been an innovative surgical treatment option in patients with liver failure since 1989.^1,2 Although this procedure is common today in many transplant centers, the risk of morbidity and mortality for the donor continues to be a leading concern for surgeons and donors.³

Although adult-to-adult LDLT outcomes for postoperative complications are similar to donor transplant recipients, there are many concerns about donor morbidity reported.^1-7 Until now, many studies have been published, reporting median 16% adult donor morbidity after LDLT.¹ The reported severe postoperative complications are mostly abdominal, and pulmonary complications have a lower incidence. Potential postoperative pulmonary complications (POPC) of donors include pneumonia, atelectasis, pleural effusion, and pulmonary embolism.^8-11

Nowadays, liver transplant is the main treatment option with a better result of survival than other treatment methods for end-stage liver patients. Unfortunately, there are many more patients waiting for liver transplants than there are available deceased-donor organs. Therefore, LDLT is an important source of liver grafts for these patients but there are some risks for the donors. Therefore, liver donor candidates have some understandable concerns while making a decision about donating their organ, even though they would save and/or improve the quality of life of a transplant candidate recipient.

This study was performed to evaluate respiratory complications of liver donation surgery in our center. We also aimed to investigate the factors affecting postoperative respiratory complications on living liver donors.

Materials and Methods

Patients and evaluation
The medical records of adult liver donors who had donation surgery at Baskent University Hospital between 1988 and 2013 were analyzed retrospectively. The study was approved by the Ethical Review Committee of the Institute. All of the protocols conformed with the ethical guidelines of the 1975 Helsinki Declaration. The demographic features, smoking status, comorbid diseases, medications, and pulmonary function tests (PFTs) were recorded. The actual value and percentage of forced vital capacity (FVC%), forced expiratory volume in the first second (FEV₁%), FEV₁/FVC ratio, and forced midexpiratory flow (FEF_25%-75%) were obtained. Preoperative sequential lesions on chest radiography and oxygen saturation as measured by pulse oximetry were noted. The type of inhalational anesthetic agent used during the operation, anatomic side of liver resection, duration of surgery, length of stay in the intensive care unit, and hospital stay were noted in the database.

Early (within 1 month) and late (≥ 1 month after surgery) pulmonary complications were recorded. Pleural effusion, pneumonia, respiratory in­sufficiency, atelectasis, pulmonary embolism, dia­phragmatic eventration, and bronchospasm were all considered pulmonary complications. These data were obtained from physical examination, chest radiographs, and thoracic computed tomography scans. The findings on thoracic computed tomo­graphy were grouped as pleural effusion, con­solidation, atelectasis, coexisting consolidation, and combinations of these radiographic findings. Bronchoscopic lavage culture results were noted in patients who underwent bronchoscopic examination.

Statistical analyses
Data analysis was performed with statistical software (IBM SPSS Statistics for Windows, Version 20.0, IBM Corp., Armonk, NY, USA). Continuous variables were expressed as mean or median ± standard deviation. The chi-square test was used to compare qualitative variables. Spearman rank correlation was used to analyze correlation between quantitative variables. All P values were 2-sided, and P ≤ .05 was considered statistically significant.

Results

A total of 188 living liver donors, including 92 females (48.9%) and 96 males (51.1%), were analyzed in the study (Table 1). The mean age of patients was 33.7 ± 8.4 years. There were various comorbidities in 13 patients (6.9%) including chronic obstructive pulmonary disease (COPD), asthma, hypertension, rheumatoid arthritis, and diabetes mellitus (Table 1). Preexisting pulmonary disease was observed in 3 donors, but none of them had any respiratory complaints before the donation surgery.

There were 84 donors (44.7%) who never smoked, 67 donors (35.6%) who were current smokers (10.65 ± 10.36 pack-years) before surgery, and 37 donors (19.7%) who were ex-smokers. The POPCs were detected in 7 current smokers (10.4%) and 7 patients who never smoked (8.3%). There was no statistical correlation observed between smoking status and POPC occurrence (P > .05).

There were some pathologic findings in 47 patients (25%) in preoperative chest radiographs.The PFTs showed normal results except in 1 patient who had COPD and PFTs that showed mild airway obstruction. All donor preoperative oxygen saturation values by pulse oximetry were normal (96.8 ± 1.1 mm Hg).

The type of hepatectomy procedures were listed in Table 2. Mean duration of donor surgery was 7.6 ± 1.7 hours. There were 3 types of inhalational anesthetics used during surgery (Table 3). There was no correlation between POPC and type of inhalational anesthetics, duration of surgery, or type of hepatectomy (P > .05).

Total hospitalization length of stay of the donors was 7.02 ± 4.5 days. Most patients (176) were discharged from the intensive care unit to the regular service within 24 hours. Early mobilization and respiratory physiotherapy were performed from the first day after surgery in 186 patients (98.9%). The incidence of early postoperative complications was 17% (n = 32), and 16 of these patients (8.5%) had POPC; of these, 2 POPC were detected within the first day of surgery and the others were detected between the second and seventh day after surgery. Most POPC were minor complications including atelectasis, pleural effusion, and pneumonia. There was 1 major POPC, which was a pulmonary embolism that occurred on the fourth day after surgery (Table 4). Atelectasis accompanied by pleural effusion (n = 5) was the most common POPC, and isolated atelectasis (n = 3) and pleural effusion (n = 3) were the second most common POPCs. The other early POPC were pneumonia (n = 2), pneumonia accompanied by pleural effusion (n = 1), pneumonia accompanied by atelectasis (n = 1), and pulmonary embolism accompanied by both pneumonia and pleural effusion (n = 1). The total length of hospital stay was statistically correlated with POPC (P = .03) (Table 5). Postoperative atelectasis was significantly higher in patients with body mass index > 21 kg/m² compared with patients with body mass index ≤ 20 kg/m² (P = .027) (Table 6).

Discussion

Despite the development of technical advances and the increasing experience about liver resection surgery in specialized centers, the surgery remains a concern because of the risk of postoperative morbidity and mortality. The safety profile of hepatectomy probably can be improved if surgeons and medical staff have comprehensive knowledge of the expected complications and expertise in treatment. This study was performed to demonstrate the possible pulmonary complications in living-liver donors who underwent liver donation surgery in our transplant center.

Smoking has a major effect on outcomes after organ transplant for donors and recipients. The poor effects of smoking on outcomes of surgical procedures, particularly in solid-organ transplants, are well known.¹⁰ Smoking increases all-cause mortality, including problems with the cardio­vascular system and infections that may account for most deaths in liver recipients.¹² Some studies have shown beneficial effects of smoking cessation on liver and kidney recipients.^13,14 However, there are insufficient data about smoking-related morbidity and mortality in liver donors.

In our study population, 104 patients (55.3%) were smokers and 84 patients (46.7%) were non­smokers. We observed no correlation between smoking status and early or late POPC. In our center, we recommend the cessation of smoking 8 weeks before the surgery for both donors and recipients to decrease postoperative complications, as recom­mended in the literature.^8,15 Therefore, we suggested that this result could be attributed to our strict smoking cessation program for donors before the surgery.

Postoperative atelectasis or pulmonary infections most commonly present 3 to 5 days after the surgery because of insufficient inspiration limited by abdominal pain and poor effects of anesthesia on respiratory muscles.¹⁶ Atelectasis is the most common pulmonary complication in living-liver donors (range, 13%-26%).^7,16 In 2 recent studies, POPC also was evaluated, but there were no data about atelectasis occurrence rate.^2,3 In the present study, atelectasis was detected only in 3 patients (1.6%). As in many centers, respiratory physio­therapy and early mobilization strategies are being performed from the first day of surgery in our center.^17-21 We believe that our strict postoperative treatment including early mobilization, respiratory physiotherapy (incentive spirometry, chest physical therapy, and hyperinflation therapy), and post­operative analgesic techniques could be responsible for this lower incidence of early postoperative atelectasis.

Obesity is a well-known risk factor for POPC after noncardiac surgery.²² Obese liver recipients have an increased risk of perioperative complications and reduced long-term survival. In practice guidelines from the American Association for the Study of Liver Diseases and American Society of Transplantation, preoperative dietary counseling is recommended for obese liver transplant candidates (≥ World Health Organization class 1).⁸ A recent study has shown that obesity was not an independent risk factor for POPCs after hepatic resection.²³ In the present study, preoperative body mass index of donors was related to postoperative pulmonary atelectasis as a patient-related risk factor. Therefore, we suggested that living-liver donor candidates should be evaluated for a weight-reducing dietary program before donating, to reduce POPCs.

Liver surgery has not been described as a high risk factor for thromboembolic disease.²⁴ A transient hypercoagulable state has been described after hepatectomy in living liver donors, despite standard prophylaxis with low-molecular weight heparin.²⁵ The probable mechanism of hypercoagulability after hepatectomy is the release of massive amounts of factor VIII and/or von Willebrand factor and activation of the coagulation cascade because of the cut in the liver parenchyma. Pulmonary embolism could be a life-threatening postoperative problem in donors. Postoperative pulmonary embolism has been reported in a few studies with a different incidence in living-liver donors.^2,3,11,26

In our study, pulmonary embolism incidence was 1.8%. This lower rate could be attributed to our prophylactic treatment, including daily subcutaneous injection of low molecular weight heparin sodium started on the day after early and persistent mobilization, and compression sleeves, for all donors in our center. We concluded that the donors should be considered at high risk for developing thromboembolic disease and should be given appropriate anticoagulant prophylaxis as recommended in the literature.²¹ Moreover, all donor candidates should be evaluated for other known thrombosis risk factors such as obesity, smoking, drug use, and familial or personal history of throm­boembolic disease.

In our study, there were no statistical relations between PFT results and POPC. This result could be explained by the selection of donor candidates with normal lung function before donation. There was 1 patient in our study group who had mild airway obstruction on PFTs, and this patient developed no POPC. In addition, no correlation was found between comorbid diseases (n = 13) and POPC in our study group. This could be explained by the precisely controlled comorbid diseases before surgery.

In this study, total length of hospitalization was 7.02 ± 4.5 days and significantly correlated with POPC occurrence in donors. This result could be explained by an extended hospital stay to diagnose and treat POPCs in these patients.

In conclusion, LDLT is a promising treatment method for chronic liver failure patients. As with any extensive surgery involving general anesthesia, there are possible pulmonary complications of the anesthesia and surgery on liver donors, but these complications are very rare. Our study indicates that the incidence of donor complications could be decreased by some important methods including respiratory physiotherapy, weight control, and prophylaxis for venous thromboembolism.

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