Could a new anesthesia method help very underweight lung transplant patients breathe on their own after surgery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

\[1\] Inclusion Criteria 1. Age and informed consent: Age ≥18 years; able to understand the study and provide written informed consent; willing and able to comply with follow-up. 2. Transplant candidacy: Listed in CLuTR or the participating center's lung transplant waiting list and scheduled to undergo allogeneic lung transplantation. 3. Low body weight definition (core cohort criterion): Preoperative BMI \<16 kg/m², calculated using the most recent traceable preoperative height and weight within the evaluation window. 4. Preoperative support status: Not receiving ongoing invasive mechanical ventilation (endotracheal intubation or tracheostomy) and not on ECMO or other extracorporeal life support preoperatively. 5. Minimum acceptable end-organ function: LVEF ≥40%; eGFR ≥40 mL/min/1.73 m²; no evidence of acute liver failure or decompensated cirrhosis/portal hypertension; American Society of Anesthesiologists (ASA) physical status ≤ IV. 6. Infection and transmissible diseases: No evidence of active infection; no active tuberculosis; HIV/HBV/HCV status meeting center transplant requirements (e.g., undetectable viral load, where applicable). 7. Rehabilitation and support: Demonstrated potential for postoperative rehabilitation (able to participate in training) and reliable caregiving support (at least one primary caregiver). \[2\] Exclusion Criteria 1. Consent/compliance: Refusal or withdrawal of informed consent; investigator judgment that follow-up cannot be completed or presence of recurrent severe non-adherence. 2. Transplant type: Retransplantation, multi-organ transplantation, or planned lobar lung transplantation. 3. Recent major cardiovascular/cerebrovascular events: Acute coronary syndrome/myocardial infarction or stroke within the past 30 days. 4. Severe organ dysfunction/acute failure: LVEF \<40%; eGFR \<40 mL/min/1.73 m²; acute liver failure or decompensated cirrhosis/portal hypertension; acute renal failure requiring dialysis with low likelihood of recovery; significant preoperative neuropsychiatric disorder or altered mental status. 5. High-risk/severe infection: Septic shock; active extrapulmonary or disseminated infection; active tuberculosis; detectable HIV viral load (or otherwise not meeting center transplant standards). 6. High bleeding risk: Severe bronchiectasis not treated with preoperative vascular intervention or not readily correctable. 7. Malignancy: Active malignancy or malignancy with high risk of recurrence or cancer-related mortality. 8. Severe chest wall or spinal deformity: Definitively diagnosed severe thoracic cage deformity or spinal deformity. 9. Substance use/dependence: Current use of cigarettes, e-cigarettes, inhaled cannabis, or intravenous drugs. 10. Tubeless/spontaneous breathing-preserving strategy not safely feasible: Determined by the anesthesia team to have a difficult airway or unsafe supraglottic/non-intubated airway management (e.g., anticipated intraoperative airway difficulty, pharyngeal/laryngeal narrowing not suitable for a laryngeal mask airway), including but not limited to: Mallampati class \>III, mouth opening \<3 cm, thyromental distance \<5 cm, or significant airway anatomic variants (e.g., aberrant right upper lobe bronchial takeoff in a planned right lung transplant) deemed difficult to manage safely with an LMA or single-lumen tube. 11. Donor/donor lung limitations: Donor age \>60 years; donor mechanical ventilation \>14 days; positive donor airway microbiology deemed unacceptable by the transplant team. 12. Protected populations: Pregnant or breastfeeding women.