Patient 2 was a 37-year-old woman with CF (genotype: homozygous F508 deletion), an FEV1 of 34.8% of the predicted value, and a body mass index of 17.3 kg/m2. Before admission, she was completely independent, working part time as a 911 dispatcher, and enjoyed spending time with friends and family. She was admitted to a general medicine floor from the Johns Hopkins Cystic Fibrosis Clinic because of concern about exacerbation of CF. On hospital day 3, she required intubation after experiencing a suspected seizure during a bronchoscopy, resulting in admission to the MICU. She underwent a tracheostomy on hospital day 17 because of prolonged intubation and inability to wean from the ventilator. After the tracheostomy, the medical team decided to proceed with a lung transplantation workup. The 6MWT was completed as part of this workup and was performed for the first time on hospital day 21. Weaning from the ventilator took longer than anticipated, resulting in a prolonged MICU admission. Because of the prolonged admission, a second 6MWT was performed while the patient was receiving MV approximately 1 month later, on hospital day 57. This second test was performed to ensure that the patient’s physical condition and endurance had not deteriorated before transplantation, given the prolonged MICU admission.
The patient was screened daily for MV weaning with SBTs performed by the MICU respiratory therapist. Her medical history was significant for anxiety, which may have limited progress with weaning. She received lorazepam as needed to promote success with SBTs throughout the weaning process but was unable to wean to a tracheostomy collar. She played an active role in increasing the length of SBTs to prevent adverse events (such as an anxiety attack or desaturation). Subjective data (reported comfort on particular ventilator settings) and objective data (such as respiration rate, tidal volume, and VBGs) were used to assess tolerance of weaning. Although VBGs were used to assess oxygen consumption, they are not documented consistently in patient charts or in coordination with the times when the 6MWT was administered and so cannot be reported here. Data on VBGs also were difficult to obtain early in the weaning process given the short times that the patient participated in SBTs as a result of her anxiety.
The medical and transplantation teams determined that it was safest for the patient to remain in the MICU until transplantation rather than discharging her to a rehabilitation center for ventilator weaning. She underwent bilateral orthotopic lung transplantation and decannulation on hospital day 70. She was discharged to home 15 days later, on hospital day 85.