Introduction

Lung transplantation is a critical therapeutic intervention for patients with end-stage lung disease, offering the potential for significantly prolonged survival and improved quality of life1. The success of this procedure is highly dependent on the meticulous management of perioperative variables, with intraoperative anesthetic management serving as a fundamental component of the process2,3,4. Anesthesiologists are integral to the perioperative care of lung transplant recipients, with their expertise directly influencing patient outcomes5. The intraoperative management of lung transplantation presents numerous challenges, including the maintenance of hemodynamic stability, adequate oxygenation, effective analgesia, and facilitation of the surgical procedure, all while mitigating associated risks5,6,7,8,9,10. Despite the critical importance of anesthetic management in this context, there is a conspicuous lack of rigorous, evidence-based guidelines, leading to practices that are often informed by the experience and preferences of individual medical institutions11,12.

Over the past decade, China has made significant strides in lung transplantation, emerging as one of the leading countries globally in terms of the number of procedures performed annually2,13,14. Despite these advancements, there remains a paucity of comprehensive data on the intraoperative anesthetic practices employed across various hospitals in the country7. Gaining insight into these practices is essential for identifying opportunities for standardization and improvement, which are critical for enhancing patient outcomes. As the largest lung transplant center in China, Wuxi People’s Hospital plays a pivotal role in the ongoing education of anesthesiologists specializing in lung transplantation. The hospital’s anesthesiology department is also responsible for training anesthesiology trainees from across the nation2. This study seeks to address the existing knowledge gap by surveying anesthesiology trainees who have completed advanced training in lung transplantation anesthesia at Wuxi People’s Hospital, thereby providing a comprehensive overview of current anesthesia management practices in lung transplant surgeries across China.

Materials and methods

Survey

The study protocol was approved by the Ethics Review Committee of Wuxi People’s Hospital (IRB number: KY24074) and was conducted in accordance with the committee’s regulations. An anonymous online survey was administered to all Chinese trainee anesthesiologists who studied lung transplantation anesthesiology in the Department of Anesthesiology at the Affiliated Wuxi People’s Hospital of Nanjing Medical University between 2015 and 2024. Informed consent was obtained from all participants. The survey was administered using WenJuanXing (Changsha Ranxing Information Technology Co., Ltd., China) and distributed via WeChat (Tencent Holdings Limited, 2018). The questionnaire collected demographic information and details about prevailing intraoperative anesthetic practices at the participants’ respective institutions. It comprised 34 questions, including 19 single-choice and 15 multiple-choice items. A complete version of the questionnaire is available as a supplementary file. Participants were stratified into intermediate and senior groups based on their clinical experience and professional designation: doctors in charge were classified as intermediate, while associate senior doctors and senior doctors were categorized as senior. The survey responses were compared between these groups. All completed surveys were anonymously stored on the internal server of WenJuanXing.

Statistical analysis

All data were analyzed using SPSS v22.0 (IBM, USA, NY). Descriptive statistics were expressed as frequencies and percentages. Comparisons between the two groups were conducted using the χ² test or Fisher’s exact test, as appropriate. A p-value of less than 0.05 was considered statistically significant. Given the exploratory nature of the analysis, no adjustments were made for multiple comparisons.

Results

Demographic characteristics

A total of 85 lung transplantation trainee anesthesiologists from 61 hospitals were eligible for the survey, with 70 (82.4%) respondents from 52 hospitals participating. The respondents represented 22 different provinces across China (Table 1).

Table 1 Geographic distribution.
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As shown in Table 2 and 28 (40.0%) of the respondents were classified as intermediate anesthesiologists, while 42 (60.0%) were senior. Among the respondents, 52 (74.3%) were male, and 18 (25.7%) were female. Significant differences were observed between the senior and intermediate groups in terms of age (P = 0.001), level of education (P = 0.001), and years of experience in the anesthesiology department (P<0.001).

Table 2 Demographic characteristics.
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Table 3 presents data on the current status of the hospitals where the trainee anesthesiologists are employed, including metrics such as daily surgery volume, number of beds, annual pulmonary surgery volume, and annual cardiac surgery volume. Notably, 56 (80.0%) of the respondents indicated that their hospitals had performed fewer than 10 lung transplant surgeries in the past year.

Table 3 Current status of trainee anesthesiologists’ hospitals.
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Intraoperative anesthetic management in trainee anesthesiologists’ institutions

Table 4 presents the intraoperative anesthetic management practices for lung transplantation in institutions where trainee anesthesiologists are employed. Etomidate was the most frequently utilized induction agent, employed in 95.7% of cases (n = 67), followed by propofol, used in 58.6% of cases (n = 41). The preference for propofol was significantly higher among senior anesthesiologists (P = 0.031). Sufentanil was universally adopted for intraoperative analgesia (100.0%, n = 70), with remifentanil being the second most commonly used agent (71.4%, n = 50). Oxycodone (24.3%, n = 17) and fentanyl (7.1%, n = 5) were also utilized, albeit less frequently. Only two practitioners (2.9%) reported the use of ketamine for intraoperative analgesia. For muscle relaxation, cisatracurium was preferred by the majority(82.9%, n = 58), followed by rocuronium (74.3%, n = 52) and vecuronium (12.9%, n = 9). In terms of inhalational anesthetics, sevoflurane was the agent of choice for most anesthesiologists (80.0%, n = 56). Desflurane and isoflurane were less commonly used, at 21.4% (n = 15) and 7.1% (n = 5) respectively. Notably, 21.4% of respondents (n = 15) reported not using inhalational anesthetics at all.

During lung transplantation, anesthesiologists generally indicated that the lowest acceptable SpO2 levels were within the range of 85–90% (52.9%, n = 37), followed by 90–95% (35.7%, n = 25), and less than 85% (11.4%, n = 8). Regarding hemoglobin levels, the most commonly accepted range was 80–90 g/L (52.9%, n = 37), followed by 90–100 g/L (27.1%, n = 19), less than 80 g/L (12.9%, n = 9), and more than 100 g/L (7.1%, n = 5). When mechanical support was required, the vast majority of anesthesiologists (98.6%, n = 69) selected ECMO, while a smaller proportion (11.4%, n = 8) opted for cardiopulmonary bypass (CPB).

For fluid management, crystalloids were universally employed (100.0%, n = 70), with acetated Ringer’s solution being the most commonly used (71.4%, n = 50), followed by lactated Ringer’s (32.9%, n = 23). Colloids were frequently administered (62.9%, n = 44), with albumin (98.6%, n = 69), plasma(82.9%, n = 58), and hydroxyethyl starch (HES) (35.7%, n = 25) being the primary choices. Most practitioners aimed for a fluid balance between − 500 to + 500mL (64.3%, n = 45), followed by -500 to -1000mL (30.0%, n = 21) and + 500 to + 1000mL (17.1%, n = 12).

Coagulation monitoring was predominantly conducted using the activated clotting time (ACT) test (74.3%, n = 52) and thromboelastography (57.1%, n = 40), with traditional coagulation tests (32.9%, n = 23) and platelet function analysis (11.4%, n = 8) being used to a lesser extent. A small number of anesthesiologists (8.6%, n = 6), primarily those at the intermediate level (P = 0.034), reported not monitoring coagulation during surgery. Significantly more senior anesthesiologists preferred traditional coagulation monitoring methods (P = 0.016).

To achieve one-lung ventilation, all anesthesiologists utilized double-lumen endotracheal intubation (100.0%, n = 70), with a small percentage (8.6%, n = 6) also employing bronchial blockers. Pressure-controlled ventilation was predominantly used (95.7%, n = 67), while volume-controlled ventilation was applied by 51.4% of the anesthesiologists (n = 36). Following the opening of the pulmonary artery, positive end-expiratory pressure (PEEP) was most commonly set between 6-10cmH2O (77.1%, n = 54), followed by 1-5cmH2O (18.6%, n = 13), and greater than 10cmH2O (2.9%, n = 2). Tidal volumes were typically adjusted to 4-6mL/kg (68.6%, n = 48), with smaller proportions set at 6-8mL/kg (20.0%, n = 14), less than 4mL/kg (10.0%, n = 7), and greater than 8mL/kg (1.4%, n = 1). Maximum peak inspiratory pressures were most frequently maintained at 25-30cmH2O (42.9%, n = 30), followed by 30-35cmH2O (31.4%, n = 22), greater than 35cmH2O (18.6%, n = 13), and less than 25cmH2O (7.1%, n = 5).

Regarding the use of intraoperative vasoactive agents, norepinephrine was the most commonly administered (95.7%, n = 67), followed by phenylephrine (67.1%, n = 47), epinephrine (62.9%, n = 44), metaraminol (47.1%, n = 33), dopamine (37.1%, n = 26), ephedrine (37.1%, n = 26), methoxamine (21.4%, n = 15), and vasopressin (20.0%, n = 14). Pulmonary arterial hypertension was primarily managed with intravenous milrinone (64.3%, n = 45) and intravenous prostanoids (60.0%, n = 42), with inhaled nitric oxide (32.9%, n = 23) and inhaled prostanoids (15.7%, n = 11) being used less frequently.

For perioperative hemodynamic monitoring, the Swan-Ganz catheter was most commonly employed (92.9%, n = 65), followed by uncalibrated pulse contour analysis (80.0%, n = 56), calibrated pulse contour analysis (78.6%, n = 55), and transesophageal echocardiography (TEE) (67.1%, n = 47). Senior anesthesiologists were significantly more likely to utilize calibrated pulse contour analysis (P = 0.017), whereas intermediate-level anesthesiologists more frequently employed TEE (P = 0.007). Intraoperative TEE was used in all lung transplant procedures by 12 anesthesiologists (17.1%), in the majority of cases by 10 anesthesiologists (14.3%), in about half of the cases by 4 anesthesiologists (5.7%), and in a minority of cases by 29 anesthesiologists (41.4%). Fifteen anesthesiologists (21.4%) reported never using TEE during operations.

For postoperative analgesia, patient-controlled intravenous analgesia (PCIA) was the preferred method (91.4%, n = 64), followed by regional nerve blocks (81.4%, n = 57) and patient-controlled epidural analgesia (PCEA) (2.9%, n = 2).

Table 4 Intraoperative anesthetic management of lung transplantation in surveyed anesthesiologists’ hospitals.
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Discussion

This study represents the first comprehensive survey of intraoperative anesthetic management practices for lung transplantation in China, providing valuable insights into both common practices and variations among anesthesiologists. A total of 70 questionnaire responses were collected, encompassing 52 lung transplant centers across 22 provinces in China.

One limitation of the study is the incomplete coverage of all lung transplant centers, as some centers did not send their anesthesiologists to Wuxi People’s Hospital for training. Additionally, the survey responses reflect the perspectives of individual anesthesiologists, which may not fully represent the consensus within their respective departments. The use of social media (WeChat) to distribute the survey introduced another limitation, particularly regarding distribution and response rates. However, efforts were made to address this by re-contacting non-responding anesthesiologists via phone.

Despite these limitations, the data provide a comprehensive overview of anesthetic practices during lung transplantation, contributing to an understanding of the diversity in anesthetic management across China.

The predominance of etomidate as the primary induction agent (95.7%) is noteworthy. Etomidate is preferred for its minimal effects on the cardiovascular system, generally not causing significant changes in blood pressure or heart rate, making it particularly suitable for patients with heart disease or hemodynamic instability15,16,17. In contrast, only 58% of Chinese anesthesiologists selected propofol for induction, whereas in Western countries over 90% of anesthesiologists use propofol for this purpose11. Although research on the use of etomidate in lung transplantation is limited, it remains favored among Chinese anesthesiologists. Propofol has been shown to offer lung and kidney protection through its anti-inflammatory effects8,18. The preference for etomidate among Chinese anesthesiologists may be attributed to the higher proportion of critically ill lung transplant recipients in China2,13,19. Ensuring hemodynamic stability during induction is a significant challenge in these cases, which may explain the preference for etomidate due to its lesser impact on blood pressure compared to propofol15,20,21. Additionally, senior anesthesiologists in China demonstrated a significantly higher rate of propofol use, likely reflecting their extensive experience in managing critically ill patients and maintaining hemodynamic stability.

According to the survey, a majority of anesthesiologists (71.4%) preferred a combination of intravenous and inhalation anesthesia for maintenance, aligning with findings from studies conducted in Europe and the United States11,22. Among inhalation anesthetics, sevoflurane emerged as the preferred agent (80%). Research indicates that sevoflurane offers protective effects against pulmonary ischemia-reperfusion injury23,24,25.

The near-universal application of ECMO in 98.6% of Chinese lung transplant surgeries, compared to the 11.4% usage rate of CPB, reflects global trends. ECMO can be categorized into two types based on the site and method of support: veno-arterial ECMO (VA-ECMO) and veno-venous ECMO (VV-ECMO)26. According to the consensus statement from the International Society for Heart and Lung Transplantation (ISHLT) on the perioperative use of extracorporeal life support (ECLS), VA-ECMO is the preferred modality for intraoperative support27. Numerous studies have demonstrated that, compared to CPB, VA-ECMO is associated with a significantly lower risk of primary graft dysfunction (PGD) and reduced incidences of postoperative complications such as bleeding, acute kidney injury, and others27,28,29,30,31,32,33. ECMO systems provide high levels of oxygenation support and effective carbon dioxide removal, significantly improving patient survival rates during and after surgery. By reducing dependence on mechanical ventilation, ECMO minimizes the risk of lung injury associated with mechanical ventilation, thereby protecting transplanted lung tissue. Additionally, ECMO enables continued respiratory support in the postoperative period, which facilitates recovery and reduces the risk of complications34. Consequently, ECMO has become the preferred method of mechanical support for lung transplant surgeries both in China and globally26,27,33,34,35,36. With the continuous advancement of lung transplantation techniques, the complexity of perioperative management has also increased. In recent years, the hybrid extracorporeal membrane oxygenation and cardiopulmonary bypass (ECMO/CPB) circuit has gradually become a new option in lung transplantation surgery. This hybrid circuit combines the advantages of VA-ECMO and CPB, enabling flexible switching without interrupting the extracorporeal circulation, significantly enhancing the ability to deal with unexpected situations during the operation. At the same time, this solution also shows obvious advantages in cost control37.This model is particularly effective in patients with severe pulmonary hypertension or right heart dysfunction and has been proven to be a safe, effective and economical perioperative support strategy. While using a hybrid ECMO/CPB circuit, intraoperative individualized hemodynamic status is precisely regulated through means such as TEE, ETCO2, and cerebral oxygen saturation monitoring. Through this monitoring system, a balance can be maintained between the patient’s own cardiac output and ECMO flow, ensuring adequate organ perfusion and reducing the risk of ischemia-reperfusion injury38.

In fluid management during lung transplantation, excessive fluid administration can lead to pulmonary edema, as the transplanted lung lacks a connection to the lymphatic system, reducing its ability to clear alveolar fluid39. Research has demonstrated a close association between excessive fluid infusion during surgery and the occurrence of severe PGD postoperatively40. In our study, most anesthesiologists (64.3%) aimed for a balance between fluid intake and output, while a smaller proportion (30%) preferred maintaining a slight negative balance (-500 to -1000 ml). This strategy likely reflects an attempt to balance protecting the transplanted lung with ensuring adequate systemic tissue perfusion. However, achieving a negative fluid balance could risk hypovolemia and impaired tissue perfusion, potentially leading to acute kidney injury (AKI) postoperatively41. Some studies have suggested that a moderately negative fluid management strategy during lung transplantation does not significantly affect the incidence of AKI42.

The majority of anesthesiologists in the survey preferred using albumin (98.6%) and plasma (82.9%) as colloid solutions to maintain colloid osmotic pressure and blood volume. Albumin, a natural colloid, is considered effective in maintaining plasma colloid osmotic pressure, thereby preventing fluid leakage into the interstitial space during and after surgery, which reduces the risk of pulmonary edema and related complications43. However, studies in cardiac surgery have shown that albumin, when compared to crystalloids, does not necessarily improve patient outcomes44. The use of plasma is also contentious; some research has suggested that intraoperative plasma administration may be associated with an increased risk of postoperative PGD45,46. Additionally, multiple studies have indicated that intraoperative red blood cell (RBC) transfusion is an independent risk factor for postoperative PGD45,47,48,49,50. Therefore, it is advisable to avoid or minimize component transfusions during surgery. Effective utilization of coagulation function monitoring could be a strategy to reduce transfusions5,51, yet the survey revealed that 8.9% of anesthesiologists, particularly more experienced ones, did not monitor coagulation function intraoperatively. This underscores the need for further education and promotion of coagulation monitoring practices.

Pressure-controlled ventilation was the predominant mode used by Chinese anesthesiologists(95.7%), with volume-controlled ventilation utilized by 51.4%. The most common practices included the use of low tidal volumes of 4-6mL/kg (68.6%), maintaining positive end-expiratory pressure (PEEP) levels at 6-10cmH2O (77.1%), and limiting peak inspiratory pressure to 25-30cmH2O (42.9%) and 30–35 cmH2O (31.4%). These practices align with those reported in a global survey, where pressure-controlled ventilation with low tidal volumes(6–8 mL/kg) was used postoperatively in two-thirds of lung transplant centers, and peak inspiratory pressure was typically limited to 25-30cmH2O in most centers11. Higher ventilation pressures are associated with an increased risk of ventilator-induced lung injury52,53,54. Additionally, in this study, 52.9% of anesthesiologists considered 85–90% as the lower limit for acceptable oxygen saturation, while 35.7% preferred to maintain saturation above 90%. Researches indicate that higher inspired oxygen concentrations are associated with an increased risk of PGD5,49,54. The recent ISHLT consensus recommends that regardless of the ECLS modality used, the lowest possible fraction of inspired oxygen (FiO2) should be applied during donor graft reinflation and reperfusion in order to minimize the risk of PGD27.

Norepinephrine (95.7%) was the most commonly used vasoactive agent, followed by phenylephrine (67.1%) and epinephrine (62.9%). Vasoactive medication support is often required during the perioperative period of lung transplantation. Norepinephrine was preferred due to its potent alpha-adrenergic effects, which help maintain systemic vascular resistance and blood pressure during surgery55. In hemodynamically unstable patients, the use of vasopressin as an adjunctive medication can be advantageous because it retains its vasoconstrictive effects under hypoxic and acidotic conditions and does not increase pulmonary vascular resistance11,56. Despite these benefits, only 20% of anesthesiologists in our survey chose vasopressin. Although inhaled nitric oxide (iNO) is the preferred treatment for pulmonary arterial hypertension internationally, its use in lung transplantation remains somewhat controversial57,58. Current clinical evidence does not demonstrate significant benefit, and the intraoperative administration of this inhaled medication can be cumbersome59. As a result, anesthesiologists in China may prefer to manage pulmonary artery pressure with intravenous infusions of milrinone (64.3%) or prostanoids (60.0%). However, the perioperative effects of these medications on pulmonary artery pressure require further clinical research for validation.

In this study, the extensive use of Swan-Ganz catheters (92.9%) and pulse contour analysis (80.0%) reflected advanced monitoring practices. However, the low utilization of TEE (67.1%) suggested an area for potential training and resource investment in China. A significant proportion of anesthesiologists (41.4%) reported using TEE in only a few lung transplant surgeries, and 21.4% stated that they never use TEE in such procedures. The ISHLT consensus emphasizes TEE as a standard monitoring tool, as it allows real-time evaluation of cardiac function and pulmonary vascular status. By facilitating timely interventions, TEE helps mitigate complications associated with circulatory support and is therefore recommended for widespread implementation27,60,61,62,63,64. Interestingly, this study found that intermediate-level anesthesiologists (85.7%) used TEE significantly more often during lung transplant surgeries compared to senior anesthesiologists (54.8%). This may be because younger practitioners are more receptive to learning and adopting new technologies and equipment. Our previous survey indicated that anesthesiologists have a strong desire to learn TEE7. Therefore, training and promoting the use of TEE is a crucial direction for the development of lung transplant anesthesia in China.

Pain control in lung transplant patients is crucial, as inadequate postoperative pain management can lead to increased complication rates and prolonged ICU stays65,66. Consequently, effective pain management after lung transplantation is essential. The results indicated that anesthesiologists prefer using PCIA (91.4%) and regional nerve blocks (81.4%) for postoperative pain management. PCEA was once considered the gold standard for analgesia after lung transplantation67. Thoracic epidural block has been proven superior to intravenous opioids in terms of pain control and patient satisfaction in lung transplants68,69. However, the risks of epidural hematoma and hypotension have hindered its use. In this study, only 2.9% of anesthesiologists opted for PCEA. While regional nerve blocks may gradually become an alternative to PCEA, clinical evidence for their use in postoperative pain management after lung transplantation is currently limited65,70. The latest ISHLT consensus on postoperative ECLS management recommends that, in ICU patients receiving ECLS, objective tools should be employed to assess subjective pain, and non-opioid analgesic strategies should be utilized during the postoperative period34. It is hoped that future clinical studies will further explore the application of regional nerve blocks in managing postoperative pain in lung transplant patients.

Facing the continuous innovation of global lung transplantation technology, how to translate the research results into global clinical practice and provide the basis for the formulation of future guidelines has become an important topic at present. The white paper issued by American Association for the Advancement of Transplant Anesthesia (SATA) provides a professional answer to this question. This document calls for the establishment of training objectives and milestones of lung transplantation specific ability in the training of anesthesiologists to cope with the increasing complexity and professional demand of lung transplantation surgery. Based on the six core competency frameworks proposed by ACGME, the white paper systematically puts forward the specific competency requirements that an anesthesiologist of lung transplantation should have, including patient safety, professionalism, communication skills, system-based practice, medical knowledge and patient care and operation skills. The document emphasizes that standardized transplant anesthesia courses should be developed to achieve cross-institutional consistency and high-quality training, especially in the context of uneven transplant cases and high complexity of patients’ conditions. Adopting a more formal, structured and standardized training system not only helps to improve the comprehensive quality of anesthesiologists in terms of professional skills and knowledge, but also prepares anesthesiologists to better cope with the evolving clinical challenges of lung transplantation71.

Conclusions

This study offers an insightful overview of intraoperative anesthetic management practices for lung transplantation in China, highlighting significant trends and variations. The preference for etomidate for induction reflects a focus on hemodynamic stability, contrasting with Western practices that favor propofol. The widespread use of ECMO aligns with global trends, emphasizing its crucial role in enhancing patient outcomes.

Despite these advances, the study identifies the need for standardized protocols in fluid management and coagulation monitoring to mitigate risks such as pulmonary edema and primary graft dysfunction. The reliance on albumin and plasma as colloid solutions is notable, although their efficacy remains debated. The prevalent use of pressure-controlled ventilation with low tidal volumes is consistent with global practices, but the underuse of TEE suggests a need for improvement in monitoring techniques.

In terms of postoperative pain management, patient-controlled intravenous analgesia (PCIA) and regional nerve blocks are the primary methods, with thoracic epidural analgesia being less common due to associated risks.

Overall, the study underscores the vital role of anesthesiologists in lung transplantation and identifies opportunities for standardization and education to enhance patient outcomes. Future research should focus on refining anesthetic protocols and integrating advanced monitoring tools to further improve the safety and effectiveness of lung transplantation in China.