Machine Learning Modeling of Intraoperative Hemodynamic Predictors of Postoperative Outcomes

Summary

With population aging and limited resources, strategies to improve outcomes after surgery are ever more important. There is a limited understanding of what ranges of hemodynamic variables under anesthesia are associated with better outcomes. This retrospective cohort study will analyze how hemodynamic variables during surgeries predict mortality, morbidity, Intensive Care Unit admission, length of hospital stay, and hospital readmission. The use of machine learning in a large, broad surgery population dataset could detect new relationships and strategies that may inform current practice, and generate ideas for future research.

Conditions

• Perioperative/Postoperative Complications
• Morbidity, Multiple
• Surgery
• Anesthesia
• Death

Interventions

OTHER

Blood pressure

Systolic Blood Pressure (SBP) 1. Maximum change from preoperative SBP, in a) absolute change (mmHg), and b) relative change (%)(emergency and elective cases analyzed separately) 2. Cumulative duration (minutes) \>=20% below preoperative SBP 3. Longest single episode (minutes) below a) 80, b) 90, and c)100 mmHg 4. Cumulative duration (minutes) below a) 80, b) 90, and c)100 mmHg Mean Arterial Pressure (MAP) 1. Maximum change from preoperative MAP, in a) absolute change (mmHg), and b) relative change (%) (emergency and elective cases analyzed separately) 2. Cumulative duration (minutes) \>=20% below preoperative MAP 3. Longest single episode (minutes) below a) 60, b) 65, c) 70, and d) 80mmHg 4. Cumulative duration (minutes) below a) 60, b) 65, c) 70, and d) 80mmHg

OTHER

Heart rate

1. Maximum change (beats per minute, BPM) from preoperative heart rate (positive and negative) 2. Relative change (%) from preoperative heart rate (positive and negative) 3. Maximum pulse variation (maximum heart rate minus minimum heart rate) 4. Longest single episode (minutes) a) below 60, and b) above 100BPM 5. Cumulative duration (minutes) a) below 60, and b) above 100BPM

OTHER

Use of hemodynamic medications (i.e. special medications for blood pressure)

1. Vasopressor/inotrope use (yes vs. no): phenylephrine, norepinephrine, epinephrine, vasopressin, dobutamine, or milrinone 2. Infusion of any vasopressor/inotropes above (yes vs. no) (identified by unit of weight over time) 3. Phenylephrine/ephedrine bolus (yes vs. no) (identified by unit of weight only) 4. Vasodilator use (yes vs. no): labetalol, esmolol, nitroglycerin, nitroprusside 5. Infusion of any vasodilator above (yes vs. no) (identified by unit of weight over time)

OTHER

Oxygen saturation by pulse oximetry (SpO2)

1. Longest single episode (minutes) below a) 88, and b) 90% 2. Cumulative duration (minutes) below a) 88, and b) 90%

OTHER

End-tidal Carbon dioxide (EtCO2)

1. Longest single episode (minutes) a) below 30, and b) above 45mmHg 2. Cumulative duration (minutes) a) below 30, and b) above 45mmHg

Sponsors & Collaborators

• Dalhousie University

  collaborator OTHER

• Harvard University

  collaborator OTHER

• University of Toronto

  collaborator OTHER

• University of Ottawa

  collaborator OTHER

• Janny Xue Chen Ke

  lead OTHER

Eligibility

Min Age

45 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2013-01-01

Primary Completion

2017-12-31

Completion

2017-12-31