Urinary hypoxia: An intraoperative marker of risk of cardiac surgery-associated acute kidney injury

Michael Z.L. Zhu, Andrew Martin, Andrew D. Cochrane, Julian A. Smith, Amanda G. Thrift, Gerard K. Harrop, Jennifer P. Ngo, Roger G. Evans

Research output: Contribution to journalArticleResearchpeer-review

14 Citations (Scopus)

Abstract

Background. Acute kidney injury (AKI) is common after cardiac surgery and profoundly affects postoperative mortality and morbidity. There are no validated methods to assess risk of AKI intraoperatively. Methods. We determined the association between postoperative AKI and intraoperative urinary oxygen tension (PO 2 ), measured via a fiber optic probe in the tip of the urinary catheter, in 65 patients undergoing high-risk cardiac surgery requiring cardiopulmonary bypass (CPB). AKI was diagnosed by modified Kidney Disease: Improving Global Outcomes criteria. Results. Urinary PO 2 fell during the operation, often reaching its nadir during rewarming or after weaning from CPB. Nadir urinary PO 2 was lower in the 26 patients who developed AKI (mean 6 SD, 8.9 6 5.6 mmHg) than in the 39 patients who did not (14.9 6 10.2 mmHg, P ¼ 0.008). Patients who developed AKI had longer periods of urinary PO 2 15 and 10 mmHg than patients who did not. Odds of AKI increased when urinary PO 2 fell to 10 mmHg {3.60 [95% confidence interval (CI) 1.27–10.21]} or 5 mmHg [3.60 (95% CI 1.04–12.42), P ¼ 0.04] during the operation. When urinary PO 2 fell to 15 mmHg, for more than or equal to the median duration for all patients (4.8 min/h surgery), the odds of AKI were 4.85 (95% CI 1.64–14.40), P ¼ 0.004. The area under the receiver-operator curve for this parameter alone was 0.69, and was 0.89 when other variables with P 0.10 in univariable analysis were included in the model. Conclusion. Low urinary PO 2 during adult cardiac surgery requiring CPB predicts AKI, so may identify patients in which intervention to improve renal oxygenation might reduce the risk of AKI.

Original languageEnglish
Pages (from-to)2191-2201
Number of pages11
JournalNephrology Dialysis Transplantation
Volume33
Issue number12
DOIs
Publication statusPublished - Dec 2018

Keywords

  • Biomarkers
  • Cardiopulmonary bypass
  • Hypoxia
  • Prognosis
  • Renal failure

Cite this

Zhu, Michael Z.L. ; Martin, Andrew ; Cochrane, Andrew D. ; Smith, Julian A. ; Thrift, Amanda G. ; Harrop, Gerard K. ; Ngo, Jennifer P. ; Evans, Roger G. / Urinary hypoxia : An intraoperative marker of risk of cardiac surgery-associated acute kidney injury. In: Nephrology Dialysis Transplantation. 2018 ; Vol. 33, No. 12. pp. 2191-2201.
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title = "Urinary hypoxia: An intraoperative marker of risk of cardiac surgery-associated acute kidney injury",
abstract = "Background. Acute kidney injury (AKI) is common after cardiac surgery and profoundly affects postoperative mortality and morbidity. There are no validated methods to assess risk of AKI intraoperatively. Methods. We determined the association between postoperative AKI and intraoperative urinary oxygen tension (PO 2 ), measured via a fiber optic probe in the tip of the urinary catheter, in 65 patients undergoing high-risk cardiac surgery requiring cardiopulmonary bypass (CPB). AKI was diagnosed by modified Kidney Disease: Improving Global Outcomes criteria. Results. Urinary PO 2 fell during the operation, often reaching its nadir during rewarming or after weaning from CPB. Nadir urinary PO 2 was lower in the 26 patients who developed AKI (mean 6 SD, 8.9 6 5.6 mmHg) than in the 39 patients who did not (14.9 6 10.2 mmHg, P ¼ 0.008). Patients who developed AKI had longer periods of urinary PO 2 15 and 10 mmHg than patients who did not. Odds of AKI increased when urinary PO 2 fell to 10 mmHg {3.60 [95{\%} confidence interval (CI) 1.27–10.21]} or 5 mmHg [3.60 (95{\%} CI 1.04–12.42), P ¼ 0.04] during the operation. When urinary PO 2 fell to 15 mmHg, for more than or equal to the median duration for all patients (4.8 min/h surgery), the odds of AKI were 4.85 (95{\%} CI 1.64–14.40), P ¼ 0.004. The area under the receiver-operator curve for this parameter alone was 0.69, and was 0.89 when other variables with P 0.10 in univariable analysis were included in the model. Conclusion. Low urinary PO 2 during adult cardiac surgery requiring CPB predicts AKI, so may identify patients in which intervention to improve renal oxygenation might reduce the risk of AKI.",
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Urinary hypoxia : An intraoperative marker of risk of cardiac surgery-associated acute kidney injury. / Zhu, Michael Z.L.; Martin, Andrew; Cochrane, Andrew D.; Smith, Julian A.; Thrift, Amanda G.; Harrop, Gerard K.; Ngo, Jennifer P.; Evans, Roger G.

In: Nephrology Dialysis Transplantation, Vol. 33, No. 12, 12.2018, p. 2191-2201.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Urinary hypoxia

T2 - An intraoperative marker of risk of cardiac surgery-associated acute kidney injury

AU - Zhu, Michael Z.L.

AU - Martin, Andrew

AU - Cochrane, Andrew D.

AU - Smith, Julian A.

AU - Thrift, Amanda G.

AU - Harrop, Gerard K.

AU - Ngo, Jennifer P.

AU - Evans, Roger G.

PY - 2018/12

Y1 - 2018/12

N2 - Background. Acute kidney injury (AKI) is common after cardiac surgery and profoundly affects postoperative mortality and morbidity. There are no validated methods to assess risk of AKI intraoperatively. Methods. We determined the association between postoperative AKI and intraoperative urinary oxygen tension (PO 2 ), measured via a fiber optic probe in the tip of the urinary catheter, in 65 patients undergoing high-risk cardiac surgery requiring cardiopulmonary bypass (CPB). AKI was diagnosed by modified Kidney Disease: Improving Global Outcomes criteria. Results. Urinary PO 2 fell during the operation, often reaching its nadir during rewarming or after weaning from CPB. Nadir urinary PO 2 was lower in the 26 patients who developed AKI (mean 6 SD, 8.9 6 5.6 mmHg) than in the 39 patients who did not (14.9 6 10.2 mmHg, P ¼ 0.008). Patients who developed AKI had longer periods of urinary PO 2 15 and 10 mmHg than patients who did not. Odds of AKI increased when urinary PO 2 fell to 10 mmHg {3.60 [95% confidence interval (CI) 1.27–10.21]} or 5 mmHg [3.60 (95% CI 1.04–12.42), P ¼ 0.04] during the operation. When urinary PO 2 fell to 15 mmHg, for more than or equal to the median duration for all patients (4.8 min/h surgery), the odds of AKI were 4.85 (95% CI 1.64–14.40), P ¼ 0.004. The area under the receiver-operator curve for this parameter alone was 0.69, and was 0.89 when other variables with P 0.10 in univariable analysis were included in the model. Conclusion. Low urinary PO 2 during adult cardiac surgery requiring CPB predicts AKI, so may identify patients in which intervention to improve renal oxygenation might reduce the risk of AKI.

AB - Background. Acute kidney injury (AKI) is common after cardiac surgery and profoundly affects postoperative mortality and morbidity. There are no validated methods to assess risk of AKI intraoperatively. Methods. We determined the association between postoperative AKI and intraoperative urinary oxygen tension (PO 2 ), measured via a fiber optic probe in the tip of the urinary catheter, in 65 patients undergoing high-risk cardiac surgery requiring cardiopulmonary bypass (CPB). AKI was diagnosed by modified Kidney Disease: Improving Global Outcomes criteria. Results. Urinary PO 2 fell during the operation, often reaching its nadir during rewarming or after weaning from CPB. Nadir urinary PO 2 was lower in the 26 patients who developed AKI (mean 6 SD, 8.9 6 5.6 mmHg) than in the 39 patients who did not (14.9 6 10.2 mmHg, P ¼ 0.008). Patients who developed AKI had longer periods of urinary PO 2 15 and 10 mmHg than patients who did not. Odds of AKI increased when urinary PO 2 fell to 10 mmHg {3.60 [95% confidence interval (CI) 1.27–10.21]} or 5 mmHg [3.60 (95% CI 1.04–12.42), P ¼ 0.04] during the operation. When urinary PO 2 fell to 15 mmHg, for more than or equal to the median duration for all patients (4.8 min/h surgery), the odds of AKI were 4.85 (95% CI 1.64–14.40), P ¼ 0.004. The area under the receiver-operator curve for this parameter alone was 0.69, and was 0.89 when other variables with P 0.10 in univariable analysis were included in the model. Conclusion. Low urinary PO 2 during adult cardiac surgery requiring CPB predicts AKI, so may identify patients in which intervention to improve renal oxygenation might reduce the risk of AKI.

KW - Biomarkers

KW - Cardiopulmonary bypass

KW - Hypoxia

KW - Prognosis

KW - Renal failure

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U2 - 10.1093/ndt/gfy047

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