Effect of Night Float Call on Sleep and Activity Patterns Among Anesthesia Residents

With increasing awareness about physician fatigue and its effect on patient safety, residency programs are increasingly transitioning to a night float call system. In other industries, multiple night shifts in a row can cause a disruption in the circadian rhythm, sleep debt, shift work disorder, that is related to chronic medical conditions such as obesity and cardiovascular disease. We will evaluate the effect of different call structures on resident activity, sleep and self reported measures of wellness using a commercially available Fitbit device.

Study Overview

• Status: Completed
• Conditions: Fatigue; Sleep Disturbance; Sleep Disorder, Shift Work

Detailed Description

Participants will be recruited via an email once they are scheduled for a week of night float in the Stanford Main Operating room or on their Obstetric Anesthesia rotation. Potential participants who are taking prescription medications that might affect their alertness during the study period will not be enrolled.

The investigators will quantify the changes in sleep pattern and activity during different call rotations. Self reported aspects of well being including fatigue, physical function, and positive affect will be assessed with NIH PROMIS surveys periodically during the study period. The investigators will use the Fitbit Alta HR data to quantify the change in total amount of sleep, sleep interruption and sleep phase and steps per day. Data will be analyzed only when it is coincident with heart rate data to correct for periods when the device is not used.

Activity will not alter from the participants normal except that they will wear the Fitbit and respond to the NIH PROMIS surveys over the study period.

Data from NIH PROMIS surveys, Fitbit and provided demographic information including age, sex and BMI, and number of previous night float periods previously completed. After association, data will be completely de-identified.

All data will be normalized to the participant's baseline value during the run-in week. The call week and post call week will be analyzed with a time series mixed effects model using R and/or NONMEM (a program for Nonlinear Mixed Effects Modeling). The effects of the above demographic variables will be assessed as potential covariates.

The investigators anticipate that this observational study will be the first of many studies looking at the effects of changing sleep patterns on activity and well-being

• Study Type: Observational
• Enrollment (Actual): 55

Contacts and Locations

Study Locations

• United States
  • California
    • Palo Alto, California, United States, 94305
      • Stanford Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

We will recruit participants who are PGY2-5 and part of the Stanford Hospital Department of Graduate Medical Education, which means they will generally be between 26-36 years of age. We will aim to recruit an equal number of males and females which is reasonable give the demographic distribution of Anesthesia residents. Finally, we aim to have a people with a variety of races and ethnicity involved but this will not be specifically targeted or evaluated due to the limited pool of eligible subjects.

Description

Inclusion Criteria:

• All residents (PGY2-5) who have been scheduled for either general operating room night float call or obstetric anesthesia rotation

Exclusion Criteria:

• Participants who report taking prescription medications that may effect alertness during the study period will not be enrolled.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
General Anesthesia Night Float; The residents will be followed over a three week period - one week prior to night float (baseline), the week of night float, and one week after night float (recovery). Participants will be asked to fill out PROMIS surveys weekly.
Obstetric Anesthesia Rotation; The residents will be followed and asked to wear the fitbit over a four week period during their rotation. Participants will complete three PROMIS surveys over the four week rotation, and as well as a follow-up PROMIS survey one week after the study period has completed

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Total Sleep Hours During Night Float	The investigators will compare total sleep hours per 24 hour period during a baseline week, a night float week, and a recovery week	3 weeks
Change in Rapid Eye Movement Sleep Hours During Night Float	The investigators will compare total Rapid Eye Movement sleep hours per 24 hour period during a baseline week, a night float week, and a recovery week	3 weeks
Change in Daily Steps during Night Float Week	The investigators will compare Steps per 24 hour period during a baseline week, a night float week, and a recovery week	3 weeks
Trends and Recovery Time in Total Sleep Hours, Rapid Eye Movement, and Daily Steps during a random night call schedule	The investigators will compare change in fitbit sleep and steps data during random call night schedule and recovery after the call night during the obstetric anesthesia rotation	4 weeks
Comparison in sleep and activity patters between a night float call schedule and a random night call schedule	The investigators will compare trends in sleep hours, REM sleep, and steps between night float and random call schedule. Time to recovery to baseline sleep patterns will be assessed.	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cohort 1: Change in PROMIS Positive Affect, Sleep Disturbance and Fatigue Scores During Night Float Week	Participants will take a survey prior to starting night float, at the end of night float week, and after one recovery week. The questions on the PROMIS survey are answered on a Likert scale and normalized to a scale 1-100 based on national average. The mean value for each survey is 50. A higher score would represent increased level of positive affect.	3 weeks
Cohort 2: Change in PROMIS Positive Affect, Sleep Disturbance, and Fatigue Scores throughout the Obstetric Anesthesia Rotation	Participants will take a baseline survey prior to starting the rotation, at the halfway point, at the end of the four weeks, and one week after the conclusion of the study period.	3 weeks
Change in PROMIS Positive Affect, Sleep Disturbance and Fatigue Scores over the study period in a night float versus a random call night system	The week to week changes in PROMIS scores between night float and a random call system will be assessed.	4 weeks

Collaborators and Investigators

• Sponsor: Stanford University
• Investigators: Study Director: Alexandra Ruan, MD, Stanford University; Principal Investigator: Pamela Flood, MD, Stanford University

Publications and helpful links

General Publications

• Lee HA, Lee HJ, Moon JH, Lee T, Kim MG, In H, Cho CH, Kim L. Comparison of Wearable Activity Tracker with Actigraphy for Sleep Evaluation and Circadian Rest-Activity Rhythm Measurement in Healthy Young Adults. Psychiatry Investig. 2017 Mar;14(2):179-185. doi: 10.4306/pi.2017.14.2.179. Epub 2017 Mar 6.
• Belayachi J, Benjelloun O, Madani N, Abidi K, Dendane T, Zeggwagh AA, Abouqal R. Self-perceived sleepiness in emergency training physicians: prevalence and relationship with quality of life. J Occup Med Toxicol. 2013 Sep 21;8(1):24. doi: 10.1186/1745-6673-8-24.
• Asken MJ, Raham DC. Resident performance and sleep deprivation: a review. J Med Educ. 1983 May;58(5):382-8. doi: 10.1097/00001888-198305000-00003.
• Cavallo A, Jaskiewicz J, Ris MD. Impact of night-float rotation on sleep, mood, and alertness: the resident's perception. Chronobiol Int. 2002 Sep;19(5):893-902. doi: 10.1081/cbi-120014106.
• Davis MC, Kuhn EN, Agee BS, Oster RA, Markert JM. Implications of transitioning to a resident night float system in neurosurgery: mortality, length of stay, and resident experience. J Neurosurg. 2017 Apr;126(4):1269-1277. doi: 10.3171/2016.5.JNS152585. Epub 2016 Jul 8.
• Dunn LK, Kleiman AM, Forkin KT, Bechtel AJ, Collins SR, Potter JF, Kaperak CJ, Tsang S, Huffmyer JL, Nemergut EC. Anesthesiology Resident Night Float Duty Alters Sleep Patterns: An Observational Study. Anesthesiology. 2019 Aug;131(2):401-409. doi: 10.1097/ALN.0000000000002806.
• Nizamuddin SL, Nizamuddin J, Latif U, Tung A, Klafta JM, Lee SM, Ku CM, Stahl DL, Lee J, Shahul SS. Be Active and Be Well? A Cross-sectional Survey of US Anesthesia Residents. J Educ Perioper Med. 2020 Apr 1;22(2):E640. doi: 10.46374/volxxii-issue2-nizamuddin. eCollection 2020 Apr-Jun.

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2019
• Primary Completion (Actual): November 30, 2021
• Study Completion (Actual): August 30, 2024

Study Registration Dates

• First Submitted: August 24, 2021
• First Submitted That Met QC Criteria: September 8, 2021
• First Posted (Actual): September 13, 2021

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 13, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: Fatigue; Medical Education; Internship and Residency; Work Schedule Tolerance; Sleep Disruption; Physician Well-Being; physician Burnout
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Dyssomnias; Chronobiology Disorders; Occupational Diseases; Fatigue; Sleep Wake Disorders; Sleep Disorders, Circadian Rhythm
• Other Study ID Numbers: 51495

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No