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Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition of Hypotension Dr Liwei Ren Anaesthetic Trainee Nepean Hospital August 2013
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Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Jan 13, 2016

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Page 1: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery

Toward an Empirical Definition of Hypotension

Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery

Toward an Empirical Definition of Hypotension

Dr Liwei RenAnaesthetic Trainee

Nepean HospitalAugust 2013

Dr Liwei RenAnaesthetic Trainee

Nepean HospitalAugust 2013

Page 2: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

• Anesthesiology, september 2013

• Featured in “This Month in Anesthesiology”

• Editorial review

Page 3: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

• Q: association between the introperative hypotension and postoperative acute kidney injury (AKI) and myocardial injury?

Page 4: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Methods

• Retrospective cohort study

• Cleveland clinic, Ohio 1/2005-9/2010

• Electronic medical record system

Page 5: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 6: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Measurement

• Introperative BP (invasive and noninvasive)

• Minutes with hypotension

Page 7: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Outcomes measurement

Outcomes measurement

• Primary

• AKI

• Cr 1.5-fold or 0.3mg/dl (26.5μmol/L)

• Myocardial injury

• Trop>=0.04μg/l or creatine kinase >=8.8 ng/ml

• Secondary

• MI, heart failure and cardiac arrest

• Mortality within 30 days

Page 8: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Statistics

• ANOVA for patients characteristics

• Chi-square for frequency

• Adjusted odds ratios and associated 95% CI and P values (statistical significance P<0.05)

• Sensitivity analyses performed

Page 9: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 10: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

ResultsResults

• Primary

• AKI 7.4%

• Myocardial injury 2.3%

• Secondary

• Cardiac complication 2.8%

• Death within 30 days of surgery 1.5%

Page 11: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Defining Hypotension

• MAP <?60? 55mmHg

Page 12: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 13: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 14: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Defining Hypotension

• Excluded patients with MAP<55mmHg

• Modest but statistically significant risk of AKI for a MAP of 55-59 mmHg (more than 5 min). OR 1.65.

• No risk of AKI associated with MAP>60 or myocardial injury with MAP>55mmHg

Page 15: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Final model category

• Time spent with MAP<55mmHg

• 0 min

• 1-5

• 6-10

• 11-20

• >20

Page 16: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 17: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 18: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 19: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Discussion

• MAP<55mmHg a/w AKI and myocardial injury and cardiac complications

• Risk escalates rapidly and no safe duration for MAP<55mmHg

• Therapeutic target - high M&M a/w AKI, myocardial injury

• Healthy vs critically ill patients

• e.g.217 Pt, MAP>82 required to prevent AKI

• 31pt, SBP<90 more than 30 min a/w higher cardiac enzymes

Page 20: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Limitations and bias

• retrospective study

• a single center

• potential residual confounders

• excluded population

• group without postoperative creatinine excluded

• longer operation, higher risks of hypotension

• invasive vs noninvasive BP measurement

• lack of data on adverse cerebral outcomes

Page 21: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Strengths of the study

• Large cohort

• Diverse surgical types and comorbidities

• Electronic BP recording

Page 22: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Conclusion

• Time spent with MAP less than 55 during noncardiac surgery is independently associate with an increased risk of AKI and myocardial injury

• Not for all patients

• Further trials required to determine whether outcomes improve with intervention of hypotension

Page 23: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.

Thank you!

.

Page 24: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.
Page 25: Journal Club : Relationship between Intraoperative Mean Arterial Pressure and Clinical Outcomes after Noncardiac Surgery Toward an Empirical Definition.