title: Ambulatory blood pressure and Holter monitoring of emergency physicians before, during, and after a night shift.
abstract: BACKGROUND
  Occupational stress may affect measured hemodynamic and electrocardiographic variables. Data describing the physiologic effects of work on the emergency physician (EP) are sparse.
  
  
  OBJECTIVE
  To determine whether blood pressure (BP) and heart rate variability (HRV) of the EP are affected during a night shift in the ED.
  
  
  METHODS
  This prospective study evaluated BP and HRV in attending EPs at an urban academic medical center for a 24-hour period during which a night shift was scheduled. Participants were fitted with an oscillometric ambulatory BP device and a Holter monitor at 1500 hours on the day of a night shift. The monitors were worn continuously before, during, and after a night shift (2300-0700) in the ED and were removed at 1500. Systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), heart rate (HR), measures of HRV, and occurrence of cardiac dysrhythmias were evaluated. Comparisons were made for ED and non-ED awake periods and non-ED sleep periods.
  
  
  RESULTS
  Twelve participants completed the study. Eight (67%) subjects were men and 4 (33%) were women. Age ranged from 28 to 40 years (mean 34.1+/-4.1). Results were analyzed using repeated-measures ANOVA. An elevation of mean DBP (5.5 mm Hg+/-4.37; p < 0.05; 95% CI 1-10) during night shift activity was seen. A trend toward elevation of SBP, MAP, and HR was discernible. HRV measures indicated a significant relative increase in sympathetic vs parasympathetic tone and an increase in HR of prework and work compared with postwork. Dysrhythmias observed included sinus tachycardia, sinus bradycardia, sinus pause, atrial premature beats, atrial couplets and triplets, supraventricular tachycardia, and premature ventricular contractions.
  
  
  CONCLUSIONS
  The elevation of DBP during a night shift suggests that these patterns of BP variability are activity- or stress-related rather than a result of a true diurnal variation. HRV analysis suggests that sympathetic tone is heightened both before work and during work. The implications of such findings to the health of the EP warrant further investigation.
authors.affiliation: Department of Medicine, Northwestern University Medical School, Chicago, IL, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Adams
authors.forename: D M
authors.initials: DM
authors.lastname: Roxe
authors.forename: J
authors.initials: J
authors.lastname: Weiss
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: J E
authors.initials: JE
authors.lastname: Rosenthal
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D015716:Electrocardiography, Ambulatory; D004635:Emergency Medicine; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D010820:Physicians; D011446:Prospective Studies; D014940:Work Schedule Tolerance / Q000502:physiology*