VentWorld Case Studies

Published April 21, 2000

William French, MA, RRT
Lakeland Community College, Kirtland, OH

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JH is a 67 year old male transferred from the acute care hospital to a skilled nursing facility because of failure to wean from ventilatory support. He was in the hospital for three weeks prior to transfer because of an exacerbation of COPD and CHF, leading to ventilatory failure. JH has a long history of both COPD and CHF. Upon admission to the hospital, he was 70" (177.8 cm) tall and weighed 140 lbs. (64 Kg).


In the hospital, JH was placed on a Puritan-Bennett 7200 for ventilatory support. Three days prior to transfer, he had a tracheostomy performed and a #8 Shiley trach tube inserted. Upon transfer the patient was on the following ventilator settings:

Mode SIMV Rate 6 bpm
Tidal Volume 600 mL Peak Flow 60 Lpm (decelerating pattern)
FIO2 .35 Pressure Support +10 cmH2O
Humidity HME

The patient was admitted to the transitional unit of the skilled nursing facility and placed on a Lifecare PLV 102 with the following settings:

Mode SIMV Rate 6 bpm
Tidal Volume 600 mL Peak Flow 60 Lpm
O2 bleed in 4 Lpm

Once the patient was stabilized on these settings, it was noted that he had a spontaneous respiratory rate of 12 to 14 breaths per minute and a spontaneous tidal volume of 200 to 300 mL. He appeared to be comfortable and required occasional tracheal suctioning for moderate amounts of thick pale yellow sputum. His SpO2 stabilized at 95%.

Six hours after admission, the following arterial blood gas data were obtained:

pH 7.43 PaO2 68 mmHg
PaCO2 52 mmHg SaO2 94%
HCO3- 36 mEq Hgb 14.6 gm

Two days later, the respiratory therapist notes a significant increase in the patient’s apparent work of breathing. His temperature was 38.2 degrees Celsius. A chest x-ray showed an infiltrate in the right base. There was a noted increase in sputum production. In response to this change in the patient’s condition, he was placed on antibiotics and started on vigorous bronchial hygiene. His SpO2 remained between 92% and 95% on the same ventilator settings. However, because of the apparent pneumonia and increase in respiratory work, it was decided to change from SIMV to assist/control. The ventilator rate was set at 10; however, the patient consistently triggered the ventilator at 14 to 18 bpm. Within fifteen minutes of assist/control, the SpO2 dropped from 94% to 85%. There was no other noticeable change in the patient’s condition. In response, the patient’s oxygen bleed in was increased to 6 Lpm; this resulted in a SpO2 of 93%.

Two days later, the patient’s pneumonia began to resolve and the patient was restored to SIMV at the original settings. Fifteen minutes after the change in mode, the SpO2 went up to 97%.

Within three weeks of admission to the skilled nursing facility, the patient was successfully weaned completely from ventilatory support and was eventually decannulated and sent home.


What are the mechanisms that contributed to the successful wean? What might have caused the episode? Do you think the staff recognized and managed the case appropriately? Post your thoughts or ask other questions related to this case.

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