Intraoperative Inhalation of Indocyanine Green for Near-Infrared Visualization of Adult Intralobar Pulmonary Sequestration
This paper demonstrates that intraoperative aerosolized indocyanine green inhalation combined with near-infrared thoracoscopy safely and effectively visualizes the ventilation-based boundary of adult intralobar pulmonary sequestration, enabling precise and minimally invasive resection.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Inside the human chest, the lungs are designed to breathe, drawing air in and pushing it out through a complex, branching network of airways. Sometimes, a small section of lung tissue becomes disconnected from this normal breathing system. This condition, known as intralobar pulmonary sequestration, leaves a patch of lung that cannot exchange oxygen because it is cut off from the main air passages. While this tissue is useless for breathing, it often remains attached to the rest of the lung and can cause infections or bleeding. The challenge for surgeons is that this rogue tissue looks exactly like healthy lung tissue to the naked eye. Without a clear way to tell where the healthy lung ends and the diseased tissue begins, surgeons often have to remove large sections of the lung to ensure they do not leave any of the problem behind, which can unnecessarily reduce a patient's breathing capacity.
A team of surgeons at Peking University People's Hospital recently tested a new way to solve this problem using a special dye and a camera that sees light invisible to the human eye. They treated four adults who had this condition by having them breathe in a mist of indocyanine green, a fluorescent dye, during surgery. Because the diseased lung tissue is cut off from the airways, it cannot breathe in the mist, while the healthy lung fills with it. When the surgeons looked through a special camera, the healthy lung glowed with a bright green light, while the diseased patch remained dark. This created a sharp, glowing line that showed exactly where to cut, allowing the surgeons to remove only the necessary tissue and save the rest of the lung.
The story of this procedure began with four adults, ranging in age from thirty-one to sixty-three, who arrived at the hospital with symptoms like coughing, sputum production, or coughing up blood. Before the operation, scans confirmed that each patient had a specific patch of lung tissue supplied by an abnormal artery but disconnected from the normal airways. The surgical team placed the patients under general anesthesia and used a special breathing tube that allowed them to control the air going into each lung separately. They then connected a nebulizer, a device that turns liquid into a fine mist, to the tube leading to the healthy lung. For ten to fifteen minutes, the patients inhaled a mist containing the indocyanine green dye.
Once the dye had been inhaled, the surgeons began the operation using a video-assisted thoracoscopic approach, which involves making small cuts and using a camera to see inside the chest. They switched the camera to a near-infrared mode, a setting that makes the dye glow. The results were immediate and clear. The healthy lung tissue, which had successfully inhaled the mist, lit up with a uniform green fluorescence. In stark contrast, the sequestered tissue, which was cut off from the air supply, remained completely dark. This created a distinct, glowing border between the two areas. The surgeons used this visual guide to mark the exact line where the healthy lung ended, ensuring they would not cut too little or too much.
In three of the four cases, the dark, non-glowing area was small and localized. Following the glowing boundary, the surgeons were able to perform a wedge resection, removing just the small, diseased piece of tissue while leaving the rest of the lung intact. In the fourth case, the dark area covered a large portion of the lower lung, involving multiple segments. The clear visual map showed that a small removal would not be enough, so the surgeons performed a lobectomy, removing the entire lower section of the lung. Throughout the process, the patients remained stable, with no drops in oxygen levels or other complications related to the dye. All four patients recovered well, and follow-up scans three months later showed that their lungs had fully re-expanded with no remaining disease.
This approach offers a distinct advantage over previous methods that relied on injecting the dye into a vein. When dye is injected into the bloodstream, it highlights areas based on blood flow, which can be misleading because the diseased tissue often still receives blood from abnormal arteries. The method used in this study, however, relies on the one thing that defines the problem: the lack of air. By using the airways to deliver the dye, the surgeons visualized the actual boundary of the disease rather than just its blood supply. This allowed them to see the true extent of the problem before making any cuts, helping them choose the least invasive surgery possible for each patient. The study suggests that for adults with this condition, breathing in the dye during surgery provides a safe and precise way to map the lung, ensuring that the right amount of tissue is removed while preserving as much healthy lung as possible.
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