Published online Mar 20, 2024. doi: 10.5493/wjem.v14.i1.87256
Peer-review started: September 13, 2023
First decision: November 21, 2023
Revised: November 30, 2023
Accepted: December 29, 2023
Article in press: December 29, 2023
Published online: March 20, 2024
Processing time: 187 Days and 22.2 Hours
Lung cancer prognosis is among the most unfavourable of all cancers. This is reflected in its relatively low 5-year survival rate. Therefore, there is a need to improve local tumour therapy while avoiding surgery. High-intensity focused ultrasound (HIFU) is the only highly effective non-invasive approach to ablating tumours in parenchymal organs outside the chest. A new method one-lung flooding (OLF) for complete lung sonography was developed that allows ultrasound-mediated lung tumour ablation. OLF involves unilateral lung filling with saline, which generates a suitable acoustic pathway for transthoracic application of HIFU in the lung. Saline filling of one lung requires one-lung ventilation of the contralateral lung.
Breathing and lung movement during HIFU procedures can result in incomplete tumour ablation or collateral damage. Superimposed high-frequency jet ventilation (SHFJV) can reduce respiratory motion. However, it is unclear whether unilateral SHFJV allows adequate haemodynamics and gas exchange.
This study aimed to compare SHFJV with pressure-controlled ventilation (PCV) during OLF by assessing hemodynamics and gas exchange relative to the animal position.
SHFJV or PCV were used alternately to ventilate the non-flooded lungs of 12 anaesthetised pigs during OLF in different body positions. Haemodynamic variables and arterial blood gas levels were measured using both ventilation modalities.
Unilateral SHFJV yielded lower carbon dioxide removal than PCV; however, it did not result in elevated carbon dioxide levels. SHFJV exhibited slightly decreased oxygenation in pigs in supine position and RLP compared with PCV. The lowest arterial partial oxygen pressure and arterial partial oxygen pressure/ inspired oxygen fraction (Horowitz index) values were observed in SP [13.0; interquartile range (IQR): 12.6-5.6 and 32.5 (IQR: 31.5-38.9) kPa]. Conversely, SHFJV yielded the highest shunt fractions in all animal positions (highest in the RLP: 0.30).
In this porcine model, unilateral SHFJV may provide adequate ventilation to animals in different positions during OLF. Lower oxygenation and carbon dioxide removal rates compared with PCV did not lead to hypoxia or hypercapnia.
SHFJV can safely minimise ventilation-induced lung motion during lung tumour ablation.