Heart rate variability may identify patients who will develop severe bradycardia during spinal anaesthesia.
OBJECTIVE
The reported incidence of cardiac arrest during spinal anaesthesia is 6.4+1.2 per 10,000 patients. Many of these arrests occurred in healthy young patients during minor surgery. This raises the question of whether some of them were avoidable. We investigated the value of Heart Rate Variability (HRV) to identify patients prone to developing severe bradycardia during spinal anaesthesia.


METHODS
Eighty ASA I-II patients, 21-60 years of age, undergoing elective surgery under spinal anaesthesia were studied. The HRV was assessed for 25 min before the spinal block. Two spectral components of HRV were calculated: a low-frequency (LF) and a high-frequency (HF) component. Patients were grouped according to whether bradycardia did or did not develop during spinal anaesthesia.


RESULTS
Nineteen patients developed severe bradycardia (<45 b.p.m.). The mean value of HF before spinal anaesthesia was significantly increased in the bradycardic group (P<0.05). The correlation between baseline heart rate (HR(baseline)) and minimum heart rate and LF, HF during spinal anaesthesia was significant (P<0.01). A receiver operator curve characteristic analysis showed a sensitivity and specificity of HF and HR(baseline) of 65% and 74%, respectively, to predict bradycardia <45 b.p.m. after spinal anaesthesia.


CONCLUSIONS
The present study shows that HF and clinical factors such as patient's HR(baseline) could identify patients prone to developing severe bradycardia during spinal anaesthesia.
Department of Anaesthesiology, University Hospital of Heraklion, Crete, Greece. aikchatzimichali@gmail.com
A
A
Chatzimichali
A
A
Zoumprouli
M
M
Metaxari
I
I
Apostolakis
T
T
Daras
N
N
Tzanakis
H
H
Askitopoulou
D000328:Adult; D000775:Anesthesia, Spinal / Q000009:adverse effects*; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D001919:Bradycardia / Q000139:chemically induced*; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D018570:Risk Assessment; D055815:Young Adult