Summary of MedSun Reports Describing Adverse Events With High Frequency Oscillatory Ventilators
MedSun: Newsletter #25, June 2008

Over the past 2 years, MedSun has received 8 adverse event reports associated with the High Frequency Oscillatory Ventilator device manufactured by SensorMedics/Viasys/Cardinal Health. The reports were submitted by 6 hospitals between July 2006 and January 2008. The most frequently reported device problems were (please note, several problems are often reported in one report):
•5 events where the ventilator stopped or lost power
•1 event where the driver module stopped
•1 event where the diaphragm was stuck
•1 event where the ventilator settings were drifting

Of the reports that listed patient age, two had a patient age listed as less than 21 years and five had a patient age listed as greater than 21 years. Of the reports that listed patient gender, a total of three reports involved female patients and a total of four reports involved male patients.

These MedSun reports contribute to FDA’s post-market experience and understanding of problems associated with the use of these devices.

The purpose of providing this summary, and the following reports, is to inform you about problems reported to FDA by the MedSun clinical community. These, as well as non-MedSun reported problems involving this device may also be investigated by searching FDA’s on-line MAUDE database available at:

High Frequency Oscillatory Ventilator
Device Device Identifiers Event Description
Ventilator, High Frequency Oscillator 3100B Oscillator stopped while in use. Respiratory therapist and RNs bagged patient and attempted to troubleshoot equipment w/o success. Device removed from use. BioMed Dept tested w/ initial circuit setup; tech unable to get airway pressure with provided setup. Replaced pt circuit w/ new circuit. Unit ran 12 hrs over course of 2 days w/o problem, holding correct airway pressure. 2000hr PM and calibration done as precaution and device returned to service.
Ventilator, High Frequency Oscillator 3100A The nurse noted that the ventilator (vent) suddenly stopped. The nurse immediately began bagging the patient and summoned RT who was on the unit. Per RT, it was hard to restart the ventilator. Within the hour, the oscillator ventilator lost power and stopped again. The vent alarmed appropriately and the patient was immediately placed on another vent. Cardinal/Viasys was notified and a trouble ticket and complaint were issued for evaluation and repair of the ventilator. Cardinal did note that the machine would be due for its 7 year preventative maintenance (PM), Driver Power Module replacement this year. There was no adverse effects to the patient. The current hour meter reading was 10398. Settings were flow 25 lpm, Insp% 33, pressure limits low 18 cm H2O and high 35 cm H2O. Vent alarm settings low 18 cm H2O and high 35 cm H2O. Vent monitored readings were fiO2 0.62, MAP 21 cm H2O nad amplitude 54 cm H2O. Last service was 32 months ago by Viasys. The unit hour meter reading was 4640.
Ventilator, High Frequency Oscillator 3100B Patient on High Frequency Oscillating Ventilator (HFOV) when the Ventilator stopped oscillating, the nurse was in the room and immediately started to bag. Patient never desaturated, and was by all accounts fine. The driver assembly just stopped on this 3100B oscillator. The oscillator does not have onboard diagnostics or error code logs or even user alarm logs.
Ventilator, High Frequency Oscillator 3100B The respiratory therapist reports that the ventilator settings were drifting. "On each ventilator check the knobs were being turned a little to obtain the original settings. The settings were set as follows: mean airway pressure (MAP) 32, amplitude (Delta P) 75, frequency (Freq) 4, and O2 100%. The ventilator was checked per protocol and the ventilator settings were as follows: MAP 21, Delta P 92, Freq 0.6, and O2 60%. The arterial blood gases (ABG's) were poor to begin with, they had become slightly worse but returned to baseline once the ventilator was changed out.
Ventilator, High Frequency Oscillator 3100B Upon turning on the oscillator, it shut down spontaneously. Three more attempts to start the oscillator resulted in automatic shut down. Providers noticed a burning smell coming form the oscillator which was replaced with a new unit. The patient was not harmed.
Ventilator, High Frequency Oscillator 3100A Cardiac monitor was attached to patient and running efficiently. Nurse at bedside noticed that oscillator spontaneously shut itself off. No alarms sounded, and Mean Arterial Pressure read -22. Manual resuscitation of patient was initiated. Lights for restart button and 45 second silence did not display. Respiratory therapist arrived, troubleshoot routine started: check for leaks, used battery back-up. No response from machine. Representative was called. Replacement machine sent.
Ventilator, High Frequency Oscillator 3100BThe High Frequency Oscillatory Ventilator 3100B started to make odd, loud noises. The diaphragm appeared to be getting stuck. The ventilator was changed at that time. In switching the ventilator out, the patient had a slight oxygen desaturation. He quickly recovered to the state he was in previous to the incident.
Ventilator, High Frequency Oscillator 3100B Patient on 3100B Oscillatory Ventilator that failed. Manual ventilation was initiated without any patient compromise. New ventilator was set up.

Additional Information:

FDA’s on-line MAUDE database available at:

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