Hyperbilirubinaemia after major thoracic surgery: comparison between open-heart surgery and oesophagectomy

Abstract

Hyperbilirubinaemia is a common occurrence in patients who are admitted to intensive care units (ICUs) after major surgery, and it is associated with high mortality. We investigated the incidence of hyperbilirubinaemia after two major types of thoracic surgery: open-heart surgery and oesophagectomy. In order to identify the risk factors associated with hyperbilirubinaemia after major surgery, we compared the incidence after open-heart surgery with that after oesophagectomy. < 0.05). In the open-heart surgery group, duration of surgery was 465 ± 24 min for the patients without hyperbilirubinaemia and 571 ± 26 min for the patients with hyperbilirubinaemia. In the oesophagectomy group, the procedure durations were 415 ± 17 min and 493 ± 20 min, respectively. The overall mortality rate was 8% in the open-heart surgery group; the rate was 12% in those with hyperbilirubinaemia, but 5% in those without hyperbilirubinaemia. No members of the oesophagectomy group died, with or without hyperbilirubinaemia. Infection significantly affected both the occurrence of hyperbilirubinaemia and mortality in the open-heart surgery group. In the subgroups from the open-heart surgery group, 5% (three out of 65) of those without hyperbilirubinaemia (or evidence of infection) died; of the patients with hyperbilirubinaemia, 3% (one out of 38) of those without infection died and 23% (seven out of 30) with detected infection died. After open-heart surgery and oesophagectomy, approximately half of the patients studied had higher levels of serum total bilirubin. Time spent in surgery was significantly related to the occurrence of hyperbilirubinaemia. Infection significantly affected mortality and total bilirubin levels after open-heart surgery. Control of infection plays a crucial role in the prevention of hyperbilirubinaemia and in reducing mortality.

Background:

Hyperbilirubinaemia is a common occurrence in patients who are admitted to intensive care units (ICUs) after major surgery, and it is associated with high mortality. We investigated the incidence of hyperbilirubinaemia after two major types of thoracic surgery: open-heart surgery and oesophagectomy. In order to identify the risk factors associated with hyperbilirubinaemia after major surgery, we compared the incidence after open-heart surgery with that after oesophagectomy.

Results:

< 0.05). In the open-heart surgery group, duration of surgery was 465 ± 24 min for the patients without hyperbilirubinaemia and 571 ± 26 min for the patients with hyperbilirubinaemia. In the oesophagectomy group, the procedure durations were 415 ± 17 min and 493 ± 20 min, respectively. The overall mortality rate was 8% in the open-heart surgery group; the rate was 12% in those with hyperbilirubinaemia, but 5% in those without hyperbilirubinaemia. No members of the oesophagectomy group died, with or without hyperbilirubinaemia. Infection significantly affected both the occurrence of hyperbilirubinaemia and mortality in the open-heart surgery group. In the subgroups from the open-heart surgery group, 5% (three out of 65) of those without hyperbilirubinaemia (or evidence of infection) died; of the patients with hyperbilirubinaemia, 3% (one out of 38) of those without infection died and 23% (seven out of 30) with detected infection died.

Conclusion:

After open-heart surgery and oesophagectomy, approximately half of the patients studied had higher levels of serum total bilirubin. Time spent in surgery was significantly related to the occurrence of hyperbilirubinaemia. Infection significantly affected mortality and total bilirubin levels after open-heart surgery. Control of infection plays a crucial role in the prevention of hyperbilirubinaemia and in reducing mortality.

Introduction

].

]. In order to prevent its development, it is important to know the risk factors for hyperbilirubinaemia.

The purpose of the present study was to examine the incidence and nature of postoperative hyperbilirubinaemia in patients undergoing different kinds of thoracic operations, to identify the perioperative and surgical risk factors associated with postoperative hyperbilirubinaemia, and to determine how postoperative hyperbilirubinaemia is related to mortality and morbidity.

Statistical analysis

< 0.05 was considered statistically significant.

Incidence and nature of hyperbilirubinaemia

).

Incidence of hyperbilirubinaemia according to surgical procedure

No significant differences in the incidence of hyperbilirubinaemia were observed between the surgical procedures.

Incidence of postoperative infection and hyperbilirubinaemia

).

For patients who had both hyperbilirubinaemia and post-operative infection in C and E groups, peaks of TB value were 8.5 ± 2.49 mg/dl in the C group and 3.4 ± 0.23 mg/dl in the E group, which occurred on PODs 11 and 5, respectively. In both groups, postoperative infection correlated closely with the development of hyperbilirubinaemia.

Risk factors for hyperbilirubinaemia

shows the factors that were considered to be related to the development of hyperbilirubinaemia. In both groups, patients with hyperbilirubinaemia were in surgery for significantly longer than those without. In the C group, preoperative concentration of serum bilirubin also correlated with postoperative hyperbilirubinaemia. Liver enzyme data did not differ significantly between the patients with and without hyperbilirubinaemia.

Analysis of risk factors for postoperative hyperbilirubinaemia

<0.05, versus patients without hyperbilirubinaemia (HYB).

Mortality and morbidity

).

Effect of infection on the incidence of postoperative hyperbilirubinaemia

<0.05, versus patients without hyperbilirubinaemia (HYB).

Duration of ICU stay

<0.05, versus patients without HYB.

Discussion

The present study found that hyperbilirubinaemia developed in 56% of patients in the ICU who had undergone open-heart surgery or oesophagectomy; that infection during the perioperative period correlated with the development of hyperbilirubinaemia; that other risk factors for hyperbilirubinaemia were operative time and volume of blood transfused during surgery; and that in the open-heart surgery group (C group) mortality was significantly higher for patients with hyperbilirubinaemia than for those without it.

]. Here, we compare the incidence of hyperbilirubinaemia after open-heart surgery and oesophagectomy. This comparison is helpful in evaluating the co-occurrence of CPB with hyperbilirubinaemia after surgery.

<0.05, versus HYB.

] pointed out that, despite a decade of advance in CPB and anaesthesia techniques, the incidence of hyperbilirubinaemia after cardiac operations with CPB did not decrease. Various reasons have been advanced to explain the development of postoperative hyperbilirubinaemia. The present study clearly shows that the longer the operative time and the larger the volume of blood transfused, the higher the incidence of postoperative hyperbilirubinaemia. The patients in this study spent longer times in the operation room than those in other reports; this may be one of the reasons why the incidence of hyperbilirubinaemia was comparatively high.

is connected to the development of hyperbilirubinaemia, the incidence of hyperbilirubinaemia would have been higher in the C than in the E group. The present results show no difference between the groups, however, which would suggest that CPB is not a major factor in the postoperative development of hyperbilirubinaemia.

We also evaluated the effect of bacterial infection on the development of hyperbilirubinaemia. Bacterial infection is a known cause of hepatic dysfunction, and hyperbilirubinaemia often occurs with sepsis. After major surgery, bacterial infection is a common complication that probably increases the risk of hyperbilirubinaemia. Clinically, it is difficult to diagnose every case of postoperative bacterial infection reliably. For the purpose of the present study, which used retrospective data, we arbitrarily defined infection using broad criteria for assessing infection in the critically ill.

]. They did not present any explanation for why TB increased late after operation. The present results suggest a possible answer, however. In the patient sample studied, those with bacterial infection showed peak TB levels on POD 11 in the C group and POD 5 in the E group; in addition, peak levels were generally higher in patients classified as infected.

<0.05, versus infection.

] was 269 ± 6 min, which is a shorter operative period than for either the C (517 ± 25 min) or the E (464 ± 19 min) group studied in the present study.

]. The results of the present study suggest that postoperative infection correlates with hyperbilirubinaemia in the later postoperative period.

] suggests that postoperative hyperbilirubinaemia is mainly due to an increase in unconjugated bilirubin of haemolytic origin. These factors may influence the development of hyperbilirubinaemia soon after open-heart surgery with CPB. The rapid postoperative development of hyperbilirubinaemia in patients in the E group is clearly due to stress factors other than CPB.

] reported high mortality for critically ill patients who received large volumes of transfused blood; the present results concur with this finding.

] reported that patients with high preoperative levels of TB were more likely to develop postoperative hyperbilirubinaemia. We also found that patients in the C group who developed postoperative hyperbilirubinaemia had higher levels of TB in blood samples taken before surgery.

In conclusion, after open-heart surgery and oesophagectomy, the levels of serum TB in about half of the patients in the present sample increased to hyperbilirubinaemic levels. The operative time correlated well with the occurrence of hyperbilirubinaemia. Infection significantly correlated with both mortality and TB levels after open-heart surgery; early diagnosis and control of infection is crucial to prevent worsening hyperbilirubinaemia and associated mortality.

Acknowledgements

We are grateful to Dr Fujino Y for insightful comments regarding the manuscript.

Keywords

• hepatic function
• hyperbilirubinaemia
• oesophagectomy
• open-heart surgery