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Communication Latencies of Apple Push Notification Messages Relevant for Delivery of Time-Critical Information to Anesthesia Providers

Rothman, Brian S. MD*; Dexter, Franklin MD, PhD; Epstein, Richard H. MD, CPHIMS

doi: 10.1213/ANE.0b013e318299a7f7
Technology, Computing, and Simulation: Research Report

BACKGROUND: Tablet computers and smart phones have gained popularity in anesthesia departments for educational and patient care purposes. VigiVU is an iOS application developed at Vanderbilt University for remote viewing of perioperative information, including text message notifications delivered via the Apple Push Notification (APN) service. In this study, we assessed the reliability of the APN service.

METHODS: Custom software was written to send a message every minute to iOS devices (iPad®, iPod Touch®, and iPhone®) via wireless local area network (WLAN) and cellular pathways 24 hours a day over a 4-month period. Transmission and receipt times were recorded and batched by days, with latencies calculated as their differences. The mean, SEM, and the exact 95% upper confidence limits for the percent of days with ≥1 prolonged (>100 seconds) latency were calculated. Acceptable performance was defined as mean latency <30 seconds and ≤0.5% of latencies >100 seconds. Testing conditions included fixed locations of devices in high signal strength locations.

RESULTS: Mean latencies were <1 second for iPad and iPod devices (WLAN), and <4 seconds for iPhone (cellular). Among >173,000 iPad and iPod latencies, none were >100 seconds. For iPhone latencies, 0.03% ± 0.01% were >100 seconds. The 95% upper confidence limits of days with ≥1 prolonged latency were 42% (iPhone) and 5% to 8% (iPad, iPod).

CONCLUSIONS: The APN service was reliable for all studied devices over WLAN and cellular pathways, and performance was better than third party paging systems using Internet connections previously investigated using the same criteria. However, since our study was a best-case assessment, testing is required at individual sites considering use of this technology for critical messaging. Furthermore, since the APN service may fail due to Internet or service provider disruptions, a backup paging system is recommended if the APN service were to be used for critical messaging.

Published ahead of print June 11, 2013.

From the *Division of Multispecialty Adult Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee; Division of Management Consulting, Department of Anesthesia, University of Iowa, Iowa City, Iowa; and Department of Anesthesiology, Jefferson Medical College, Philadelphia, Pennsylvania.

Accepted for publication April 12, 2013.

Published ahead of print June 11, 2013.

Funding: Departmental funding.

The authors declare no conflicts of interest.

Reprints will not be available from the authors.

Address correspondence Richard H. Epstein, MD, Department of Anesthesiology, Jefferson Medical College, 111 S 11th St., 6215F Philadelphia, PA 19107. Address e-mail to richard.epstein@jefferson.edu.

© 2013 International Anesthesia Research Society