Critical Care Medicine-Pulmonary Disorders>>>>>Respiratory Diagnostic Modalities and Monitoring
Question 6#

A 45-year-old man with a history of idiopathic pulmonary fibrosis is admitted to the ICU intubated and sedated after single lung transplantation. On postoperative day 1, the patient’s oxygen requirement increases. He remains afebrile, and his arterial blood gas shows PaO₂ 90 mm Hg on FiO₂ 50%. The respiratory therapist reports increased secretions from his endotracheal tube. The patient is on ceftazidime, vancomycin, voriconazole, inhaled amphotericin B, and valganciclovir.

Which of the following is the BEST next step in management?

A. Lighten the sedation and try to extubate him today
B. Perform a bronchoscopy and send the bronchial lavage from the native lung for culture and expand antibiotic coverage meropenem
C. Give the patient a pulse steroid therapy with methylprednisolone
D. Increase his FiO₂ to 100%

Correct Answer is C

Comment:

Correct Answer: C

Acute graft rejection after lung transplantation is one of the major causes of early graft loss. There are two mechanisms in which acute rejection could present: acute cellular rejection (ACR) and antibodymediated rejection (AMR). ACR is the leading cause of acute graft rejection in lung transplant patients. AMR is uncommon due to the extensive crossmatching between the donor and recipient for patients undergoing lung transplantation.

ACR could present with a wide range of symptoms, from asymptomatic, cough, shortness of breath to acute respiratory failure. Pulse steroids are the treatment of choice of ACR (answer C). AMR, on the other hand, can be resistant to steroids, and plasmapheresis might be an effective option.

Primary graft dysfunction (PGD) is another major cause of early morbidity and mortality after lung transplantation. It can present as mild to severe lung injury, and chest x-ray can reveal diffuse allograft infiltrations. Donor risk factors such as smoking history, alcohol use, African American race, female gender, and age are associated with increased risk of PGD. Prevention and treatment of PGD are unclear due to lack of appropriately powered clinical studies. However, lung protective ventilation therapy is recommended. ECMO could be used as salvage therapy for patients that remains hypoxemic despite maximum ventilation support.

Lung transplant patient should remain intubated (answer A) if there is a suspicion of acute rejection, as this process is progressive and may lead to severe respiratory failure. Since this patient is afebrile and on appropriate antimicrobial prophylaxis, the addition of a carbapenem (answer B) would not add any benefit. Increasing FiO₂ does not add any clinical benefits to this patient, and may be harmful.

References:

1. Habre C, Soccal PM, Triponez F, et al. Radiological findings of complications after lung transplantation. Insights Imaging. 2018. doi:10.1007/s13244-018-0647-9.
2. Potestio C, Jordan D, Kachulis B. Acute postoperative management after lung transplantation. Best Pract Res Clin Anaesthesiol. 2017;31(2):273- 284.
3. Morrison MI, Pither TL, Fisher AJ. Pathophysiology and classification of primary graft dysfunction after lung transplantation. J Thorac Dis. 2017;9(10):4084-4097.