Percutaneous lung biopsy in the horse.

This study tested whether a core needle lung biopsy can be safely and effectively performed in standing, unsedated horses, finding that all samples were diagnostically useful and complications were minimal. Two horses had brief coughing of blood that needed no treatment, and necropsy showed no visible damage at biopsy sites.

What question did the study ask and why does it matter?

• Whether percutaneous lung biopsy using a cutting (Vim Tru-Cut) needle can reliably obtain diagnostic tissue in horses.
• Whether the procedure can be performed in standing horses under local anesthesia without sedation, minimizing risk and logistics associated with general anesthesia.
• What short-term complications occur and whether there is grossly visible damage at the biopsy site.

How was the study done?

• Subjects: 20 horses underwent percutaneous lung biopsy.
• Technique: A cutting core needle (Vim Tru-Cut) was used.
• Anesthesia: Local anesthesia only; horses remained standing and unsedated.
• Specimen assessment: Tissues were evaluated histologically for adequacy and content (parenchyma and large airways).
• Safety assessment: Horses were monitored for immediate complications; after the study, all were euthanized and the biopsy sites were examined grossly at necropsy.

Key findings

• Diagnostic yield: 100% of biopsy specimens were suitable for histologic examination.
• Tissue composition: All samples contained pulmonary parenchyma and large airways, indicating that the technique accesses both deep lung tissue and airway structures.

Safety and complications

• Immediate complications: Hemoptysis occurred in 2 of 20 horses (10%); it was self-limiting and required no treatment.
• Postmortem findings: No gross abnormalities were identified at biopsy sites on necropsy, suggesting minimal macroscopic injury from the procedure.

Interpretation and clinical relevance

• Feasibility: Percutaneous lung biopsy with a Tru-Cut needle is technically feasible in standing, unsedated horses using local anesthesia.
• Diagnostic utility: The high adequacy rate supports the method as a reliable way to obtain histopathology for lung disease workups when cytology (e.g., BAL/TTW) is insufficient.
• Safety profile: The low rate and mild nature of observed complications support use in appropriately selected cases, with preparation to manage transient bleeding.
• Potential value: Sampling that includes both parenchyma and larger airways may enhance diagnosis of interstitial, bronchiolar, and mixed lung diseases where tissue architecture matters.

Strengths of the study

• Direct histologic confirmation that all cores were adequate, a key determinant of clinical usefulness.
• Objective post-procedure evaluation via necropsy to detect gross injury at biopsy sites.
• Demonstration that sedation is not strictly necessary, potentially widening access and reducing procedural risk and cost.

Limitations and what is not known

• Population details: The health status and diagnoses of the horses are not described, limiting generalizability to clinical patients with active lung disease.
• Follow-up: Only immediate outcomes were reported; longer-term complications (e.g., delayed pneumothorax, infection, adhesions) were not assessed.
• Technique specifics: Needle size, number of passes, laterality, and imaging guidance (if any) were not detailed, making replication and risk benchmarking harder.
• Outcome scope: Complications beyond hemoptysis were not specified; absence of mention does not confirm absence (e.g., subclinical pneumothorax not reported).
• Study design: No comparison to sedated horses, alternative needles, or imaging-guided approaches; small sample size limits precision of complication estimates.

How this fits with other diagnostic options

• Versus BAL/TTW: Bronchoalveolar lavage and transtracheal wash yield cells and secretions for cytology and culture but not preserved tissue architecture; biopsy adds histopathology for interstitial and structural disease.
• Versus thoracoscopy/thoracotomy: Biopsy is less invasive and can be done standing, but yields smaller samples than surgical approaches.
• Imaging guidance: Modern practice commonly uses ultrasound guidance to choose a safe, aerated window and may further reduce complications; this study does not clarify whether guidance was used.

Clinical takeaways

• In experienced hands, percutaneous Tru-Cut lung biopsy can provide high-quality histologic samples in standing, unsedated horses under local anesthesia.
• Expect a low rate of mild hemoptysis; monitor closely post-procedure and have plans to manage bleeding if it occurs.
• Consider patient selection, coagulation status, and available imaging to optimize safety; adapt technique (e.g., site selection, number of passes) based on individual risk.

Future directions

• Define complication rates with standardized reporting (including pneumothorax) and longer follow-up.
• Compare sedation versus no sedation, needle gauges, and ultrasound guidance to refine best practices.
• Evaluate diagnostic yield and impact on case management in horses with specific lung diseases in clinical settings.