Transbronchial lung biopsy versus transbronchial lung cryobiopsy in critically ill patients with undiagnosed acute hypoxemic respiratory failure: a comparative study

Abstract

Background: In patients with acute hypoxemic respiratory failure whose diagnosis is not established after initial evaluation, obtaining a histopathological diagnosis may improve the patients' prognosis. This study aims to compare the safety profile and diagnostic yields between transbronchial lung biopsy (TBLB) and transbronchial lung cryobiopsy (TBLC) in these patients.

Methods: A retrospective comparative study was conducted in a 26-bed intensive care unit over a 5-year period. The consecutive patients with acute hypoxemic respiratory failure who underwent TBLB or TBLC were included to determine the potential etiology. Patients characteristics, procedure related complications, pathological and multidisciplinary discussion (MDD) diagnostic yields, treatment modification and 28-day survival were analyzed. Prognostic factors were identified by Cox regression analysis.

Results: Forty-five and 25 consecutive patients underwent TBLB and TBLC, respectively. The patients underwent TBLC were more critical. There was no significant difference in overall procedure related complications of patients underwent TBLB and TBLC [15.6% (7/45) vs 28.0% (7/25), p = 0.212]. The rate of pathological diagnostic yield [72.0% (18/25) vs 37.8% (17/45), p = 0.006], MDD diagnostic yield [84.0% (21/25) vs 55.6% (25/45), p = 0.016] and subsequent treatment modification [84.0% (21/25) vs 57.8% (26/45), p = 0.025] in patients underwent TBLC were significantly higher than those in patients underwent TBLB. Multivariate analysis revealed that MDD diagnosis [HR 0.193 (95% CI 0.047-0.792), p = 0.022] and treatment modification [HR 0.204 (95% CI 0.065-0.638), p = 0.006] may be prognostic protective factors.

Conclusions: TBLC can lead to an increased chance of establishing a diagnosis, which could significantly improve the patients' prognosis, with an acceptable safety profile.

Keywords: Acute respiratory failure; Complications; Cryobiopsy; Diagnostic yields.

Fig. 1

Flow diagram of patient selection and comparative content in the study. MDD: multidisciplinary discussions; TBLB: transbronchial lung biopsy; TBLC transbronchial lung cryobiopsy

Fig. 2

A representational case of patient who underwent TBLC. A 51-year-old female patient was admitted to the MICU with a chief complaint of shortness of breath for two weeks. The patient was diagnosed with immune-mediated necrotizing myopathy three months ago and was treated with oral corticosteroid and mycophenolate mofetil. Chest CT showed bilateral GGOs and consolidations after admission (a). Cytomegalovirus nucleic acid was detected in BALF in the initial assessment. However, after treatment of ganciclovir for over one week, the patient's shortness of breath deteriorated. Repeat chest CT still showed progressive pulmonary infiltrations (b). Then TBLC was performed under the recommendation in the first MDD (c). Pathology of TBLC revealed abundant abnormal lymphocytes infiltrating alveolar septal capillaries and interstitium (d). Immunohistochemistry revealed CD20(+) (e), CD34 (capillaries+) (f), CD3(−), CD79α(+), PAX-5(+). The diagnosis of intravascular large B-cell lymphoma was established according to pathology in the second MDD. Unfortunately, despite receiving life-saving chemotherapy, the patient died 14 days after MICU admission. CT: computed tomography; GGO: ground-glass opacities; BALF: bronchioalveolar lavage fluid; TBLC: transbronchial lung cryobiopsy; MDD: multidisciplinary discussion