title: Low pre-operative heart rate variability and complexity are associated with hypotension after anesthesia induction in major abdominal surgery.
abstract: Significant hypotension after induction of general anesthesia is common and has the potential for serious complications. This study aimed to determine if pre-operative heart rate variability (HRV) was associated with post-induction hypotension in patients undergoing major abdominal surgery. Patients undergoing semi-elective major abdominal surgery were consecutively recruited during pre-admission clinic assessment. Exclusion criteria included cardiac conduction disease, arrhythmias or severe liver or renal disease. Ten minutes of electrocardiogram at 1024 Hz were recorded a median of 3 days pre-operatively. Pre-operative HRV parameters were compared in patients who experienced significant hypotension (fall in systolic and mean arterial pressure (MAP) >30% baseline and MAP ≤60 mmHg) versus those who remained haemodynamically stable after induction of general anesthesia with propofol and fentanyl. Patients who experienced hypotension after general anesthesia induction had significantly lower pre-operative HRV (SDNN 16 vs. 37 ms, p < 0.001), reduced spectral power (total power 262 vs. 1236 ms2, p = 0.002) and reduced correlation dimension, a measure of signal complexity (0.11 vs. 2.13, p < 0.001). Hypotension occurred relatively frequently in our cohort and was associated with a higher ASA grade (36 vs. 6% ASA 3, p = 0.036), hence post-induction hypotension and lower HRV may be associated with severity of illness or poor physiological reserve. Pre-operative HRV was a useful screening tool in identifying patients undergoing major abdominal surgery who were at risk of haemodynamic instability after anesthesia induction.
authors.affiliation: Department of Anaesthesia, St Vincent's Hospital, 390 Victoria St, Darlinghurst, NSW, 2010, Australia. docpadley@gmail.com.
authors.forename: James R
authors.initials: JR
authors.lastname: Padley
authors.affiliation: Department of Anaesthesia, St Vincent's Hospital, 390 Victoria St, Darlinghurst, NSW, 2010, Australia.|Notre Dame School of Medicine, Darlinghurst, NSW, Australia.
authors.forename: Erez
authors.initials: E
authors.lastname: Ben-Menachem
mesh_terms: D000005:Abdomen / Q000601:surgery*; D000368:Aged; D000465:Algorithms; D000758:Anesthesia / Q000379:methods*; D000768:Anesthesia, General; D001341:Autonomic Nervous System / Q000187:drug effects; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D005283:Fentanyl / Q000627:therapeutic use; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007022:Hypotension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period; D015742:Propofol / Q000627:therapeutic use; D012815:Signal Processing, Computer-Assisted; D013514:Surgical Procedures, Operative / Q000379:methods*
chemical_list: D005283:Fentanyl; D015742:Propofol
keywords: Autonomic; Cardiovascular; Induction; Propofol