Risk factors for inadvertent hypothermia during adult living-donor liver transplantation

The outcomes and biliary complications of a staged biliary reconstruction in living donor liver transplantation: a propensity score matched analysis

BACKGROUND

Uncontrolled massive bleeding and bowel edema are critical issues during liver transplantation. Temporal intra-abdominal packing with staged biliary reconstruction (SBR) yields acceptable outcomes in deceased donor liver transplantation; however, data on living donor liver transplantation (LDLT) are scarce.

METHODS

A retrospective analysis of 1269 patients who underwent LDLT was performed. After one-to-two propensity score matching, patients who underwent LDLT with SBR were compared with those who underwent LDLT with one-stage biliary reconstruction (OSBR). The primary outcomes were graft survival (GS) and overall survival (OS), and the secondary outcomes were postoperative biliary complications.

RESULTS

There were 55 and 110 patients in the SBR and OSBR groups, respectively. The median blood loss was 6500 mL in the SBR and 4875 mL in the OSBR group. Patients receiving SBR-LDLT had higher incidence of sepsis (69.0% vs. 43.6%; P < 0.01) and intra-abdominal infections (60.0% vs. 30.9%; P < 0.01). Biliary complication rates (14.5% vs. 19.1%; P = 0.47) and 1-and 5-year GS (87.27%, 74.60% vs. 83.64%, 72.71%; P = 0.98) and OS (89.09%, 78.44% vs. 84.55%, 73.70%; P = 0.752) rates were comparable between the two groups.

CONCLUSIONS

SBR could serve as a life-saving procedure for patients undergoing complex critical LDLT, with GS, OS, and biliary outcomes comparable to those of OSBR.

Effects of 20% albumin infusion therapy during liver transplantation on plasma neutrophil gelatinase-associated lipocalin level: A randomized controlled trial

The risk of acute kidney injury (AKI) after liver transplantation was lower in patients with serum albumin levels ≥3.0 mg/dL during surgery. We tested whether intraoperative infusion of 20% albumin affects neutrophil gelatinase-associated lipocalin (NGAL) level, a reliable indicator of AKI. We randomly assigned 134 patients undergoing liver transplantation into albumin group (n=70, 20% albumin 200 mL) and the control group (n=66, crystalloid solution 200 mL). The 2 study fluids were infused at 100 mL/h from the start of the anhepatic phase. The primary outcome was plasma NGAL level at 1 hour after graft reperfusion. Albumin level at the start of graft reperfusion was significantly greater in albumin group than in the control group [2.9 (2.4-3.3) g/dL vs. 2.3 (2.0-2.7) g/dL, p <0.001]. The NGAL level at 1 hour after graft reperfusion was not significantly different between the 2 groups [100.2 (66.7-138.8) ng/mL vs. 92.9 (70.8-120.6) ng/mL, p =0.46], and the AKI risk was not either (63.9% vs. 67.8%, adjusted p =0.73). There were no significant differences between the 2 groups regarding hospital readmission within 30 days/90 days after transplantation (32.6% vs. 41.5%, adjusted p =0.19 and 55.0% vs. 55.7%, adjusted p =0.87). Graft survival probability at 30 days/90 days/1 year after transplantation was 90.0%/84.3%/78.6% in albumin group and 97.0%/90.9%/89.4% in the control group [HR=1.6 (0.6-4.0), adjusted p =0.31]. In conclusion, intraoperative infusion of 20% albumin 200 mL increased the albumin level but failed to maintain serum albumin ≥3.0 mg/dL during surgery. The hypertonic albumin therapy did not significantly affect plasma NGAL level and clinical outcomes including AKI.

Forced-air prewarming prevents hypothermia during living donor liver transplantation: a randomized controlled trial

Despite various intraoperative thermal strategies, core heat loss is considerable during liver transplantation and hypothermia is common. We tested whether forced-air prewarming prevents hypothermia during liver transplantation. Adult patients undergoing living donor liver transplantation were randomly assigned to non-prewarming group (n = 20) or prewarming group (n = 20). Patients in prewarming group underwent 30-min forced-air warming before anesthetic induction. During surgery, core temperature was measured in the pulmonary artery. The primary outcome was intraoperative hypothermia (< 36.0 °C). The secondary outcomes included plasma lactate concentration. Intraoperative hypothermia risk was significantly lower in prewarming group than in non-prewarming group (60.0% vs. 95.0%, P = 0.020). The difference in hypothermia incidence between groups was greater in the post-induction phase (20.0% vs. 85.0%, P < 0.001) than in the anhepatic or post-reperfusion phase, suggesting that prewarming mainly acts on preventing post-induction core-to-peripheral heat redistribution. Hypothermia duration was significantly shorter in prewarming group (60 [0-221] min vs. 383 [108-426] min, P = 0.001). Lactate concentration decreased during 3 h after graft reperfusion in prewarming group, whereas it continuously increased in non-prewarming group (- 0.19 [- 0.48 to 0.13] mmol/L vs. 1.17 [3.31-0.77] mmol/L, P = 0.034). In conclusion, forced-air prewarming decreases the incidence and duration of intraoperative hypothermia with potential clinical benefit while mainly acting by preventing the core-to-peripheral heat redistribution.Clinical trial registration: Registered at the Clinical Research Information Service ( https://cris.nih.go.kr , [KCT0003230]) on 01/10/2018.

Visceral fat, but not subcutaneous fat, is associated with lower core temperature during laparoscopic surgery

Background

Previous studies suggest that lower BMI is a risk factor for intraoperative core hypothermia. Adipose tissue has a high insulation effect and is one of the major explanatory factors of core hypothermia. Accordingly, determining the respective influence of visceral and subcutaneous fat on changes in core temperature during laparoscopic surgery is of considerable interest.

Methods

We performed a prospective study of 104 consecutive donors who underwent laparoscopic nephrectomy. Temperature data were collected from anesthesia records. Visceral and subcutaneous fat were calculated by computed tomography (CT) or ultrasound. For ultrasound measurements, preperitoneal fat thickness was used as an index of visceral fat. Multiple linear regression analysis was performed at 30, 60, and 120 minutes after the surgical incision to identify the predictive factors of body temperature change. The potential explanatory valuables were age, sex, BMI, visceral fat, and subcutaneous fat.

Results

BMI (β = 0.010, 95%CI: 0.001–0.019, p = 0.033) and waist-to-hip ratio (β = 0.424, 95%CI: 0.065–0.782, p = 0.021) were associated with increased core temperature at 30 minutes after the surgical incision. Ultrasound measured-preperitoneal fat was significantly associated with increased core temperature at 30 and 60 minutes after the surgical incision (β = 0.012, 95%CI: 0.003–0.021, p = 0.009 and β = 0.013, 95%CI: 0.002–0.024, p = 0.026). CT-measured visceral fat was also associated with increased core temperature at 30 minutes after the surgical incision (β = 0.005, 95%CI: 0.000–0.010, p = 0.046). Conversely, subcutaneous fat was not associated with intraoperative core temperature. Male sex and younger age were associated with lower intraoperative core temperature.

Conclusions

Visceral fat protects against core temperature decrease during laparoscopic donor nephrectomy.

Comparison of bispectral index targeted end-tidal concentration of desflurane during three phases of orthotopic liver transplantation

BACKGROUND AND AIMS

Reduced inhalational anaesthetic requirement in end-stage liver disease during living donor orthotopic liver transplantation (LD-OLT) is due to increased endogenous opioids. This study evaluated the changes in bi-spectral index (BIS) monitored end-tidal desflurane (ETDes) requirements during 'dissection', 'anhepatic', and 'neohepatic' phases of LD-OLT.

METHODS

This prospective, cohort study included 40 adults undergoing LD-OLT under general anaesthesia (GA). All patients received BIS-guided desflurane GA. ETDes requirements in three phases of LD-OLT (primary objective); relationship between inhalational anaesthetic requirements and severity of liver disease; and effect of changes in mean arterial pressure (MAP) and body temperature on ETDes concentration for all three phases were also evaluated.

RESULTS

ETDes during the 'dissection' phase (2.92 ± 0.65%) was > 'anhepatic' (2.68 ± 0.85%, P = 0.049) and 'neohepatic' phases (2.58 ± 0.71%, P = 0.005). Patients with model of end-stage liver disease (MELD) score < 20 returned significantly greater ETDes than those with MELD score ≥20 during the 'dissection' (MELD <20: 3.11 ± 0.49%; MELD ≥20: 2.58 ± 0.77%, P = 0.01) and 'anhepatic'(MELD <20: 2.96 ± 0.76%; MELD ≥20: 2.17 ± 0.79%, P = 0.003) phases. A positive correlation was observed between ETDes(r = 0.584, P = 0.001) and temperature in the 'dissection' phase only.

CONCLUSION

In patients undergoing LD-OLT, BIS monitoring guidance of depth of desflurane GA suggests lower desflurane requirements during 'anhepatic' and the 'neohepatic' phase of surgery. Also, the desflurane requirement is greater in patients with lesser severity of liver disease.

The changes of intraoperative body temperature in adult liver transplantation: A retrospective study

BACKGROUND

Body temperature is poorly regulated in patients with end-stage liver disease. Due to the prolonged surgery time and anhepatic time as well as the complex surgical procedures performed in liver transplantation, the body temperature fluctuates greatly. This study investigated the effect of intraoperative body temperature fluctuations on the prognosis of liver recipients.

METHODS

The body temperatures of liver recipients recorded from the induction of anesthesia (T₀) until the end of surgery (T₁₄) were retrieved. The patients were divided into two groups: the hypothermia group (< 35 °C and ≥ 5 min) and the normothermia group (≥ 35 °C or < 35 °C but < 5 min). Intraoperative and postoperative variables were compared between the two groups, and the correlations between the duration of hypothermia and the medical variables were analyzed.

RESULTS

Of the 107 patients, 67 patients were in the normothermia group, and 40 in the hypothermia group. The lowest body temperature was at 5 min after reperfusion for the whole cohort. Compared with the normothermia group, patients in the hypothermia group were more prone to bleeding, had a longer intubation time and increased rates of bacterial infection and acute pulmonary edema after liver transplantation (P < 0.05). Hypothermia time was positively correlated with bleeding volume, intubation time, units of blood transfusions and intensive care stay, but negatively correlated with urine output.

CONCLUSIONS

The intraoperative body temperature exhibited a graphical "V" trend, and the lowest temperature was at 5 min after reperfusion. The longer the duration of hypothermia, the more unfavourable the prognosis.

What is the predictor of the intraoperative body temperature in abdominal surgery?

PURPOSE

Inadvertent hypothermia is a relatively common intraoperative complication. Few studies have investigated predictors of body temperature change or the effect of the blanket type used with a forced-air warming device during the intraoperative period. We investigated the predictive factors of intraoperative body temperature change in scheduled abdominal surgery.

METHODS

We retrospectively reviewed the data from 2574 consecutive adult patients who underwent scheduled abdominal surgery in the supine position. Temperature data were collected from anesthesia records. Multiple regression analysis was performed at 60, 120, and 180 min after the surgical incision to identify the factors influencing body temperature change. We conducted nonlinear regression analysis using the equation ΔT = α (e^-γt-1) + βt, where ΔT represented the change in intraoperative core temperature (°C), t represented the surgical duration (minutes), and α, β, and γ were constants.

RESULTS

The intraoperative core temperature change was explained by the equation ΔT = 0.59 (e^- 0.018t - 1) + 0.0043t. Younger age, higher body mass index (BMI), male sex, laparoscopic surgery, and use of an underbody blanket were associated with increased core temperature at 1 or 2 h after surgical incision. Male sex and an underbody blanket remained strong predictive variables even 3 h after surgical incision, whereas BMI had little explanatory power at this timepoint. The difference in the heating effect of an underbody versus an overbody blanket was 0.0012 °C per minute.

CONCLUSIONS

The blanket type of the forced-air warmer, age, sex, laparoscopic surgery, and BMI are predictors of intraoperative core temperature change.

Predictive factors of maternal hypothermia during Cesarean delivery: a prospective cohort study

PURPOSE

Although perioperative hypothermia may increase maternal morbidity, active warming is infrequently performed to maintain normothermia during Cesarean delivery (CD). The aim of this prospective observational study was to determine the factors associated with maternal hypothermia in this setting.

METHODS

Women scheduled for elective or emergency CD were consecutively included in this study from November 2014 to October 2015. Maternal temperature was measured using an infrared tympanic thermometer on the patient's arrival in the operating room, at skin incision, and at the end of skin suture. Maternal hypothermia was defined by tympanic temperature < 36°C at the end of skin suture. Univariate analysis was performed, followed by multivariate logistic regression analysis, in order to determine the factors associated with maternal hypothermia at the end of the surgery.

RESULTS

Three hundred fifty-nine women were included and analyzed during this study. The incidence of hypothermia was 23% (95% confidence interval, 18 to 27) among the total population included. According to multivariate analysis, obesity, oxytocin augmentation of labour, and use of active forced-air warming were associated with a decreased risk of maternal hypothermia, while maternal temperature < 37.1°C on arrival in the operating room, maternal temperature < 36.6°C at skin incision, and an infused volume of fluids > 650 mL were significantly associated with maternal hypothermia. Both goodness of fit and predictive value of multivariate analysis were high.

CONCLUSION

Several predictive factors for maternal hypothermia during CD were identified. These factors should be taken into account to help prevent maternal hypothermia during CD.

Relevance of Endoplasmic Reticulum Stress Cell Signaling in Liver Cold Ischemia Reperfusion Injury

The endoplasmic reticulum (ER) is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS). This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR), which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusion injury (IRI) of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes.

Incidence of Inadvertent Intraoperative Hypothermia and Its Risk Factors in Patients Undergoing General Anesthesia in Beijing: A Prospective Regional Survey

Background/Objective

Inadvertent intraoperative hypothermia (core temperature <36⁰ C) is a recognized risk in surgery and has adverse consequences. However, no data about this complication in China are available. Our study aimed to determine the incidence of inadvertent intraoperative hypothermia and its associated risk factors in a sample of Chinese patients.

Methods

We conducted a regional cross-sectional survey in Beijing from August through December, 2013. Eight hundred thirty patients who underwent various operations under general anesthesia were randomly selected from 24 hospitals through a multistage probability sampling. Multivariate logistic regression analyses were applied to explore the risk factors of developing hypothermia.

Results

The overall incidence of intraoperative hypothermia was high, 39.9%. All patients were warmed passively with surgical sheets or cotton blankets, whereas only 10.7% of patients received active warming with space heaters or electric blankets. Pre-warmed intravenous fluid were administered to 16.9% of patients, and 34.6% of patients had irrigation of wounds with pre-warmed fluid. Active warming (OR = 0.46, 95% CI 0.26–0.81), overweight or obesity (OR = 0.39, 95% CI 0.28–0.56), high baseline core temperature before anesthesia (OR = 0.08, 95% CI 0.04–0.13), and high ambient temperature (OR = 0.89, 95% CI 0.79–0.98) were significant protective factors for hypothermia. In contrast, major-plus operations (OR = 2.00, 95% CI 1.32–3.04), duration of anesthesia (1–2 h) (OR = 3.23, 95% CI 2.19–4.78) and >2 h (OR = 3.44, 95% CI 1.90–6.22,), and intravenous un-warmed fluid (OR = 2.45, 95% CI 1.45–4.12) significantly increased the risk of hypothermia.

Conclusions

The incidence of inadvertent intraoperative hypothermia in Beijing is high, and the rate of active warming of patients during operation is low. Concern for the development of intraoperative hypothermia should be especially high in patients undergoing major operations, requiring long periods of anesthesia, and receiving un-warmed intravenous fluids.

Bioreactance Is Not Interchangeable with Thermodilution for Measuring Cardiac Output during Adult Liver Transplantation

Background

Thermodilution technique using a pulmonary artery catheter is widely used for the assessment of cardiac output (CO) in patients undergoing liver transplantation. However, the unclearness of the risk-benefit ratio of this method has led to an interest in less invasive modalities. Thus, we evaluated whether noninvasive bioreactance CO monitoring is interchangeable with thermodilution technique.

Methods

Nineteen recipients undergoing adult-to-adult living donor liver transplantation were enrolled in this prospective observational study. COs were recorded automatically by the two devices and compared simultaneously at 3-minute intervals. The Bland–Altman plot was used to evaluate the agreement between bioreactance and thermodilution. Clinically acceptable agreement was defined as a percentage error of limits of agreement <30%. The four quadrant plot was used to evaluate concordance between bioreactance and thermodilution. Clinically acceptable concordance was defined as a concordance rate >92%.

Results

A total of 2640 datasets were collected. The mean CO difference between the two techniques was 0.9 l/min, and the 95% limits of agreement were -3.5 l/min and 5.4 l/min with a percentage error of 53.9%. The percentage errors in the dissection, anhepatic, and reperfusion phase were 50.6%, 56.1%, and 53.5%, respectively. The concordance rate between the two techniques was 54.8%.

Conclusion

Bioreactance and thermodilution failed to show acceptable interchangeability in terms of both estimating CO and tracking CO changes in patients undergoing liver transplantation. Thus, the use of bioreactance as an alternative CO monitoring to thermodilution, in spite of its noninvasiveness, would be hard to recommend in these surgical patients.

Comparison of two fluid warming devices for maintaining body core temperature during living donor liver transplantation: Level 1 H-1000 vs. Fluid Management System 2000

BACKGROUND

Rapid fluid warming has been a cardinal measure to maintain normothermia during fluid resuscitation of hypovolemic patients. A previous laboratory simulation study with different fluid infusion rates showed that a fluid warmer using magnetic induction is superior to a warmer using countercurrent heat exchange. We tested whether the simulation-based result is translated into the clinical liver transplantation.

METHODS

Two hundred twenty recipients who underwent living donor liver transplantation between April 2009 and October 2011 were initially screened. Seventeen recipients given a magnetic induction warmer (FMS2000) were matched 1 : 1 with those given a countercurrent heat exchange warmer (Level-1 H-1000) based on propensity score. Matched variables included age, gender, body mass index, model for end-stage liver disease score, graft size and time under anesthesia. Core temperatures were taken at predetermined time points.

RESULTS

Level-1 and FMS groups had comparable core temperature throughout the surgery from skin incision, the beginning/end of the anhepatic phase to skin closure. (P = 0.165, repeated measures ANOVA). The degree of core temperature changes within the dissection, anhepatic and postreperfusion phase were also comparable between the two groups. The minimum intraoperative core temperature was also comparable (Level 1, 35.6℃ vs. FMS, 35.4℃, P = 0.122).

CONCLUSIONS

A countercurrent heat exchange warmer and magnetic induction warmer displayed comparable function regarding the maintenance of core temperature and prevention of hypothermia during living donor liver transplantation. The applicability of the two devices in liver transplantation needs to be evaluated in various populations and clinical settings.