The utility of transbronchial cryobiopsy performed under conscious sedation for interstitial lung diseases in a resource constrained setting

Abstract

Background: Transbronchial biopsy (TBB) with a cryoprobe, also known as transbronchial lung cryobiopsy (TBLC), has become a well established modality for sampling lung parenchyma. TBLC is performed under general anaesthesia in the majority of centres, utilising rigid or flexible bronchoscopy. In resource-constrained settings, however, most diagnostic bronchoscopies, including TBB, are performed under conscious sedation with flexible bronchoscopy without the presence of a specialist anaesthetist.

Objectives: Given the paucity of evidence on TBLC performed under conscious sedation for interstitial lung diseases (ILD), specifically in a resource-constrained setting, we aimed to describe its utility in a pilot study.

Methods: We prospectively enrolled the first 20 patients who underwent TBLC for ILD at a large tertiary hospital in South Africa. All TBLCs were performed under conscious sedation using a cryoprobe. Patients were actively monitored for complications. The final diagnosis and decision regarding need for a surgical biopsy were made at a multidisciplinary meeting that included at least two specialist pulmonologists with an interest in ILD, a thoracic radiologist, and an anatomical pathologist with an interest in ILD.

Results: Three patients experienced complications. Two (10%) developed a pneumothorax (neither required any intervention). Bleeding that required 10 minutes of tamponade with the endobronchial blocker was observed in one case. This patient experienced no haemodynamic or respiratory compromise and was discharged the same day. There were no complications arising from the use of conscious sedation. A definitive diagnosis was made in 17/20 (85%) of the patients.

Conclusion: TBLC performed at an experienced bronchoscopy centre using a cryoprobe under conscious sedation with a dedicated sedationist was safe and well tolerated. Furthermore, it had a high diagnostic yield, and surgical lung biopsy was avoided in 85% of the patients.

Study synopsis: What the study adds. There is a paucity of evidence for the use of transbronchial lung cryobiopsy (TBLC) for the diagnosis of interstitial lung diseases (ILD) in resource-constrained settings, especially when performed under conscious sedation. In this pilot study, TBLC performed under conscious sedation was safe and well tolerated, and had a high diagnostic yield.Implications of the findings. TBLC under conscious sedation can safely be rolled out in resource-constrained settings as a first-line diagnostic procedure when lung tissue needs to be obtained in patients with ILD, as its yield is comparable to TBLC under general anaesthesia. It potentially avoids surgical lung biopsy in >80% of cases, together with the need for general anaesthesia.

Keywords: Cryobiopsy; conscious sedation; interstitial lung disease.

Fig. 1

Patients were orally intubated via a plastic bite guard. Supplementary nasal oxygen was routinely administered.

Fig. 2

A bronchial blocker (7.0 Fr/65 cm Arndt Endobronchial Blocker Set) was attached to the distal tip of the bronchoscope prior to insertion. The balloon was only inflated once the target segment was identified.

Fig. 3

The balloon was inflated, and its position was endoscopically confirmed.

Fig. 4

An example of fluoroscopy. In this case the operator retracted the probe by 2 - 3 cm prior to confirming its position again and performing the biopsy.

Fig. 5

An example of the endoscopic view when the tip of the bronchoscope is placed against the balloon to inspect for bleeding (in this case very minor)

Fig. 6

Examples of transbronchial cryobiopsy specimens obtained with a 1.7 mm probe.