Evaluation of the Nighttime Operation Impact on Liver Transplantation: A Meta-Analysis

Research Article

J Fam Med. 2021; 8(4): 1252.

Evaluation of the Nighttime Operation Impact on Liver Transplantation: A Meta-Analysis

Ziteng Zhang1#, Xiaoliang Zha2#, Xian He3, Mingbo Wang1, Xin Zhao1, Kun Zhang1, Zhilong Kang1 and Bo Ren2*

¹Department of Hepato-Biliary Surgery, Southern University of Science and Technology, China

²Department of Anesthesiology, Southern University of Science and Technology, China

³Dali University, Fifth Medical Center of PLA General Hospital, China

#These two authors contributed equally to this work

*Corresponding author: Bo Ren, Department of Anesthesiology, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, Shenzhen, 518055, China

Received: April 08, 2021; Accepted: April 26, 2021; Published: May 03, 2021


Background: Liver transplant is frequently performed at night due to the unpredictability of organ procurement and reduction of Cold Ischemia Time (CIT). Previous study reported a doubled mortality Hazard Ratio (HR) of early death and increased postoperative complications in nighttime liver transplant. This study aims to evaluate the impact of nighttime operation on patients’ survival and postoperative complications by using meta-analysis.

Methods: We performed a systematic review of the PubMed database and identified five eligible studies. Three time points (30 days, 90 days and 1 year) were explored in patients’ survival by using pooled HR. Four types of postoperative complications (vascular, biliary tract, wound and primary graft non-function) were investigated by using pooled Odds Ratio (OR). Publication bias was also performed.

Results: Our study results were contradicting with the previous report and yielded no significant difference with a HR=0.98 (95% CI=0.89-1.06) on 30 days, HR=1.12 (95% CI=0.89-1.35) on 90 days and HR=1.07 (95% CI=0.95-1.18) on 1 year in nighttime procedure. Consistent with the result of patients’ survival, no significant result was found in postoperative complications evaluation as well. None of the four complications demonstrated significant result. And we failed to detect any significant publication bias.

Conclusions: Based on current evidence, nighttime liver transplantations do not degrade patients’ survival or increase postoperative complications risk compared with daytime operations.

Keywords: Nighttime operation; Liver transplant; Meta-analysis


Sleep deprivation and fatigue have long been accepted as a potential risk factor in surgical practice with various attempts trying to assess its effects on the outcomes of patients’ safety. Lack of sleep may lead to changed attention concentration, impaired decision making capability, and the likelihood of mistakes [1]. It has been reported nighttime operation was significantly associated with higher surgical morbidity and mortality in many different studies [2,3].

Liver Transplant (LT) has emerged in recent decades as a critical surgical option for patients with end stage liver disease, such as Acute Hepatic Failure (AHF), Hepatocellular Carcinoma (HCC), long-term untreated viral hepatitis and so on. Different from other surgical procedures, time of obtaining donation consent and retrieval of the organ are unpredictable and beyond the control of the surgical team. Furthermore, prolonged Cold Ischemia (CIT) has been pointed as an independent risk factor of graft failure. Any delay in the surgical intervention would increase cold ischemia time, thus increasing the risk of postoperative complications and risk of transplant failure [4]. All these factors make nighttime operation a regular procedure in liver transplant.

Liver transplant is a highly technical demanding operation and requires high quality surgical performance to ensure its success. With the help of standardized anesthetic, postoperative intensive care procedure and advanced immunosuppressive therapies, the incidence of non-surgery-related causes of graft failure have been dramatically reduced [5]. Therefore, different studies have explored the risk of sleep deprivation and fatigue on surgery performance in liver transplant by using different comparison patterns including weekday VS weekends, daytime VS nighttime and solitary VS consecutive transplantations [6-13].

Prior publication has summarized the risk of nighttime in liver transplantation with only narrative description of two studies [14]. The aim of this investigation was to systemically analysis the risk of nighttime procedure by selecting all related studies in order to provide comprehensive evidence about nighttime procedure risk.

Materials and Methods

This study was conducted in accordance to in accordance PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) Guidelines [15].

Data sources

We systematically searched PubMed database for relevant studies up to March 2021. The search key words combination of (surgeon fatigue or sleep deprivation or night time operation or nighttime operation or nighttime procedure or at night) and (liver operation or liver transplant or liver transplantation) were used. Furthermore, relevant references within the included studies were also evaluated to exclude any missing publications.

Study selection

The searched studies were evaluated based on the following criteria: (1) study that focused on comparing nighttime with daytime, other comparison design such as weekday with weekend was excluded (2) the operation type was restricted to liver transplantation and (3) the study design was retrospective cohort study. As for language restrictions, we limited the studies to those reported in English. The selection was conducted by two independent reviewers and consensus was achieved on eligible studies.

Data extraction

The data of the included studies was extracted. For each study, the following data was collected; first author, country where the study was performed, publication year and time category. Operative information was also collected into three parts including clinical characteristics of recipients, operative characteristics and donor characteristics.

Clinical characteristics of recipients include number of recipients, age, gender, Body Mass Index (BMI), the Model for End-Stage Liver Disease (MELD) and different cause percentage of indications. Operative characteristics consist of total time (h), cold ischemia time (h) and warm ischemia time (min). Donor characteristics comprised age, gender, BMI, percentage of donation after cardiac death (DCD %) and Donor Risk Index (DRI).

Analyzed outcomes

The outcomes investigated in this study were patients’ survival and postoperative complications. Based on the data provided in the included studies, four time points in patients’ survival were calculated, which were 7 days, 30 days, 90days and 1 year. Postoperative complications were collected from four categories which were vascular, biliary tract, wound and Primary Graft Non-Function (PNF). We pooled Hazard Risk (HR) and related 95% Confidence Intervals (CI) for patients’ survival, Odds Ratio (OR) and related 95% CI for postoperative complications. In some studies which HR and 95% CI was not directly provided, we collected the Kaplan-Meier curve in the publication and calculated the relevant HR and 95% CI by using Engauge Digitizer version 4.1 and the practical methods for incorporating summary time-to-event data into meta-analysis [16].

Statistical analyses

Statistical analyses were performed by using STATA 12.0. Hazard Risk (HR) for patients’ survival, odds ratio (OR) for postoperative complications were performed respectively. Heterogeneity was assessed with a Χ² or I² test. Null heterogeneity between studies was defined when I²<40%; then we used a fixed effect model to calculate the ratio; otherwise a random effect model was applied. Additionally, publication bias was examined by Begg’s and Egger’s tests. If p value was <0.05, publication bias was statistically significant; otherwise, it was considered no publication bias.


Patients’ characteristics of the included studies

The process of study selection was shown in Figure 1. The initial research retrieved 117 records. After the removal of duplicates and reading the abstract, 22 publications were left. Then, full text was assessed to identify the eligible studies. At last, 6 studies met all the criteria and were included [9-13,17].