Abstract
Background
Pulmonary artery sling (PAS) is a rare congenital anomaly of the great vessels, often accompanied by tracheal stenosis and various intracardiac malformations. Traditionally, PAS surgeries have been performed using tracheal intubation and extracorporeal circulation. In 2015, our center began using laryngeal mask airway (LMA) ventilation combined with extracorporeal circulation to facilitate PAS surgeries. This study retrospectively analyzed the outcomes of LMA ventilation and compared them with those of traditional tracheal intubation.
Methods
A retrospective analysis was conducted on PAS surgery cases from January 2010 to December 2021. Data collected included intraoperative ventilation methods, postoperative ventilator support time, postoperative respiratory reinterventions, extracorporeal circulation time, surgery duration, tracheal stenosis degree (T)/left pulmonary artery stenosis degree (P), intensive care unit (ICU) stay duration, and postoperative hospital stay duration. The T/P ratio was calculated through preoperative imaging evaluations.
Results
Thirty-nine PAS surgery cases were analyzed, with a mean age at surgery of 14.2 ± 13.7 months (range: 1.2 months to 4.8 years) and a mean weight of 9.0 ± 3.7 kg (range: 3.8–17.9 kg). Eleven patients (28.2%) had concurrent cardiac malformations. Patients were divided into the LMA group (14 cases) and the tracheal intubation group (25 cases) based on intraoperative ventilation methods. The LMA group included three patients with concurrent intracardiac malformations (all atrial septal defects). Compared with the tracheal intubation group, the LMA group had a significantly shorter extracorporeal circulation time, lower tracheal stenosis degree (T)/left pulmonary artery stenosis degree (P), shorter postoperative ventilator support time, and ICU stay duration. The LMA group also included older patients.
Conclusion
LMA ventilation is a feasible and effective option for ventilation management during surgeries in select patients with PAS, particularly those who are older, have milder symptoms, have less severe tracheal stenosis, have smaller T/P ratios, and may or may not have simple intracardiac malformations with good cardiac function. LMA ventilation was associated with shorter ICU and hospital stays, suggesting it may serve as a reasonable alternative for selected children with pulmonary artery sling (PAS).
Keywords: Pulmonary artery sling, Laryngeal mask airway ventilation, Tracheal intubation, Airway management
Introduction
Pulmonary artery sling (PAS) is a rare congenital anomaly of the great vessels, characterized by an anomalous origin of the left pulmonary artery from the right pulmonary artery. Pulmonary artery sling (PAS) is often accompanied by complete tracheal rings (the ring-sling complex), leading to true tracheal stenosis. Patients often present with recurrent wheezing, dyspnea, respiratory distress, pulmonary infections, and dysphagia. Furthermore, PAS frequently coexists with intracardiac malformations such as ventricular septal defects, atrial septal defects, and tetralogy of Fallot. Surgical intervention is the only effective treatment for PAS with tracheal stenosis, with or without intracardiac malformations. Previous studies by the author proposed that the tracheal-to-pulmonary artery stenosis ratio (T/P ratio) can be used to evaluate the indications and risk levels for tracheoplasty surgeries [1]. In earlier studies, PAS surgeries were primarily conducted under tracheal intubation combined with extracorporeal circulation. However, tracheal intubation can cause direct damage to the airway. The stimulation from intubation can lead to edema of the airway mucosa, which affects the healing of the anastomotic site. Prolonged intubation may also result in ventilator-associated pneumonia, increasing the risk of pulmonary complications. In contrast, the use of a laryngeal mask airway (LMA) can help avoid these issues. Our center first adopted laryngeal mask airway (LMA) ventilation combined with extracorporeal circulation in 2014 to facilitate the smooth progression of PAS surgeries. This study hypothesizes that laryngeal mask airway (LMA) ventilation is non-inferior to traditional tracheal intubation in terms of perioperative safety and efficacy for PAS children with specific conditions. This study aims to retrospectively compare the perioperative outcomes of laryngeal mask airway (LMA) ventilation and tracheal intubation in pulmonary artery sling (PAS) surgery, and to explore the feasibility of LMA.
Methods
A retrospective analysis was conducted on all PAS surgery cases from January 2010 to December 2021. Data collected included intraoperative ventilation methods, postoperative ventilator support time, postoperative respiratory support reinterventions, extracorporeal circulation time, surgery duration, tracheal stenosis degree (T)/left pulmonary artery stenosis degree (P), intensive care unit (ICU) stay duration, and postoperative hospital stay duration. Preoperative chest computed tomography (CT) was routinely performed to calculate the ratio of tracheal stenosis degree (T) to left pulmonary artery stenosis degree (P) (T/P ratio). The inclusion criteria for the LMA group were as follows: preoperative imaging assessment showed tracheal stenosis degree T < 50% and tracheoplasty was not required; patients with severe tracheal stenosis or planned tracheoplasty were included in the tracheal intubation group. This decision was jointly made by the anesthesiology department and the surgical team based on the preoperative CT and bronchoscopic evaluation results.
This retrospective study was approved for ethics exemption by the Institutional Review Board of Children’s Hospital of Fudan University and included written informed consent from all participants’ guardians.
Anesthesia procedure
Right internal jugular vein catheterization and radial artery catheterization were performed after induction. Intraoperative monitoring of electrocardiogram, oxygen saturation, arterial pressure and central venous pressure was performed routinely. Preoperative flexible bronchoscopy was routinely conducted to assess tracheal stenosis. Intraoperative monitoring of arterial pressure and central venous pressure was also performed routinely.
In cases of severe tracheal stenosis or planned tracheoplasty, tracheal intubation is selected. The external diameter of 3.0 mm tracheal tube was 4.2 mm and that of 3.5 mm tracheal tube was 4.9 mm. The cuff design was low-pressure and high-volume. In the tracheal intubation group, anesthesia was induced with propofol, fentanyl, and rocuronium. The tracheal tube cuff size was chosen based on the patient’s age and weight, with the insertion depth set at three times the tube size or to the upper edge of the stenotic segment. Anesthesia was maintained with sevoflurane, with fentanyl and rocuronium administered intermittently as needed. Postoperatively, hydromorphone was provided for analgesia, and patients were transferred to the ICU with the tracheal tube in place.
In the LMA group, sedation was initiated with propofol upon the patient’s arrival in the operating room, followed by an attempt at facemask ventilation. If airway pressure was ≤ 20 cmH2O and tidal volume was ≥ 5 mL/kg, fentanyl and rocuronium were administered, and an appropriately sized LMA (LMA® Unique™), a first generation LMA, was inserted based on body weight(size 1 for < 5 kg, size 1.5 for 5 to 10 kg and size 2 for 10 to 20 kg). If facemask ventilation proved difficult, sevoflurane was used to deepen anesthesia, and tracheal intubation was performed under spontaneous breathing. The tracheal tube size and insertion depth were the same as in the tracheal intubation group. Mechanical ventilation began after LMA insertion, and flexible bronchoscopy was used to confirm the absence of leakage or gas entry into the stomach. Anesthesia was maintained with sevoflurane, with fentanyl and rocuronium administered as required. The total fentanyl dose was limited to ≤ 10 mcg/kg. At the end of surgery, neostigmine or sugammadex was administered to reverse neuromuscular blockade. The LMA was removed after the patient regained spontaneous breathing with a tidal volume of ≥ 5 mL/kg and regained consciousness. Postoperative analgesia was provided with hydromorphone as needed, and the patients were transferred to the ICU with nasal cannula oxygen therapy.
All surgeries were performed by three senior physicians with ≥ 15 years of experience in cardiothoracic surgery, and anesthesia was managed by three attending physicians specialized in cardiothoracic anesthesia, all of whom were proficient in both laryngeal mask airway (LMA) and tracheal intubation techniques. It was the routine that patients with trachea intubation were extubated in the CICU. Due to the limited experience in LMA management among the CICU physicians, LMA were removed in the operation room by the responsible anesthesiologists.
Surgical procedure
Surgeries were performed with patients in the supine position using a median sternotomy and the establishment of extracorporeal circulation. The right pulmonary artery was dissected, and the anomalous origin of the left pulmonary artery from the right pulmonary artery, posterior to the trachea, was identified and ligated. The left pulmonary artery was then freed and end-to-side anastomosed to the main pulmonary artery, with an autologous pericardial patch placed anterior and superior to the anastomosis to ensure unobstructed blood flow. In cases of severe concurrent tracheal stenosis, slide tracheoplasty was performed. For patients with concurrent intracardiac malformations, the aorta was clamped, and cardiac arrest was induced for intracardiac malformation correction. Postoperatively, the patients were transferred to the ICU. The ICU physicians were told the way of ventilation perioperatively and assessed the patients independently.
Statistical analysis
The primary outcome was postoperative mechanical ventilation time, and the secondary outcomes included ICU stay duration, hospital stay duration, etc. Owing to the retrospective nature of the study design, the outcome assessors (including parameters such as the duration of ICU stay and postoperative ventilation time) were not subjected to blinding. There is a potential for selection bias, as patients in the LMA group were more likely to exhibit milder tracheal stenosis and be of a relatively older age.
SPSS 22.0 software was used for statistical analysis. T-tests were conducted to compare mean values and standard deviations between groups, and chi-square tests were used to compare proportions. The effect sizes and their 95% confidence intervals (CIs) were calculate for each variable (mean difference [MD] for continuous variables and risk difference [RD] for binary variables). A P-value < 0.05 was considered statistically significant.
Data availability
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.
Results
Basic case information
In total, 39 PAS surgery cases were identified, and their detailed information are presented in Table 1. All of the patients had complete data and information. No missing data existed. Previous studies by the author demonstrated that the degree of tracheal stenosis (T) and left pulmonary artery stenosis (P) can reflect the relative compression of the trachea and left pulmonary artery. A T/P ratio of > 1.15 indicated the need for aggressive management of tracheal stenosis or a poor prognosis with high sensitivity and specificity. The calculation methods for T, P, and the T/P ratio are detailed in previous studies by the author [1].
Table 1.
Patients’ basic information
| Demographics | N = 39 |
|---|---|
| Surgery Age (months) |
14.2 ± 13.7 (Q1 ~ Q3: 5.7 ~ 17.8) |
| Weight (kg) |
9.0 ± 3.7 (Q1 ~ Q3: 6.0 ~ 11.4) |
| Gender | N |
| Male | 23 |
| Female | 16 |
| Preoperative Tracheal Intubation | 6(15.4%) |
| Concurrent Cardiac Malformations | 11(28.2%) |
| Ventricular Septal Defect | 3 |
| Atrial Septal Defect | 5 |
| Both | 3 |
| Tracheal Stenosis (T) | N |
| T < 78.4% | 28(71.8%) |
| T > 78.4% | 11(28.2%) |
| T/P Ratio | N |
| T/P < 1.15 | 21(53.8%) |
| T/P > 1.15 | 18(46.1%) |
| Surgery Details | N |
| Only Left Pulmonary Artery Grafting | 20(51.3%) |
| Left Pulmonary Artery Grafting + Tracheoplasty | 8(20.5%) |
| Left Pulmonary Artery Grafting + Intracardiac Malformation Correction | 10(25.6%) |
| Left Pulmonary Artery Grafting + Tracheoplasty + Intracardiac Malformation Correction | 1(2.6%) |
| Surgery Duration (min) |
165.7 ± 52.1 min (Q1 ~ Q3: 120 ~ 205 min) |
| Extracorporeal Circulation Time (min) |
86.2 ± 50.8 min (Q1 ~ Q3: 50 ~ 105 min) |
| Intraoperative LMA Ventilation (n) | 14(35.9%) |
| Intraoperative Tracheal Intubation (n) | 25(64.1%) |
| Aspiration | 0 |
| Postoperative Outcomes | |
| Mechanical Ventilation Time (h) |
155.9 ± 335.7 h (Q1 ~ Q3: 0 ~ 128 h) |
| Extubation or removal of LMA Immediately After Surgery (n) | 13 |
| < 24 h (n) | 8 |
| 24 ~ 72 h (n) | 5 |
| > 72 h (n) | 13 |
| ICU Stay Duration (days) |
14.2 ± 24.4d (Q1 ~ Q3: 1 ~ 14d) |
| Postoperative Reintubation (n) | 2 |
| Reoperation Interventions (n) | 2(5.1%) |
| Pneumonitis or Pneumonia | 0 |
| Postoperative Hospital Stay (days) |
23.3 ± 24.1d (Q1 ~ Q3: 10 ~ 29d) |
| Survival (n) | 31(79.5%) |
| Death (n) | 8(20.5%) |
Our center first adopted LMA ventilation in 2015 for pediatric patients with PAS exhibiting mild tracheal stenosis and no concurrent intracardiac malformations, yielding promising results. For patients with severe stenosis requiring tracheoplasty, traditional tracheal intubation was used for respiratory management. Over the following years, LMA ventilation was gradually introduced for patients with simple concurrent intracardiac malformations and good cardiac function. Patients were categorized into the LMA group and the tracheal intubation group based on intraoperative respiratory support methods. The medication for postoperative analgesia was hydromorphone. In LMA group, the load dose was given after LMA removal. A dose of 2 to 3 mcg/kg hydromorphone was given every 10 min if the FLACC score was over 3. The maximum load dose was 10 mcg/kg. In tracheal intubation group, the load dose of 10 mcg/kg hydromorphone was given before the patients were transferred to CICU. In both group, the nurse-control analgesia was used in the CICU. The background dose was 0.7 mcg/kg/min and the bolus dose was 0.7 mcg/kg. The bolus dose was given if the FLACC score were higher than 3. The lockout time was 10 min. The sedative medications was dexmedetomidine. Comparisons between the two groups were made regarding demographics, concurrent cardiac malformations, extracorporeal circulation time, aortic cross-clamp time, degree of tracheal stenosis (T), T/P ratio, postoperative ventilator support time, ICU stay duration, hospital stay duration, and postoperative reinterventions, as shown in Table 2.
Table 2.
Comparison between LMA and tracheal intubation groups
| Variable | LMA Group | Tracheal Intubation Group | MD/RD | 95%CI | P-value |
|---|---|---|---|---|---|
| Number of Cases (n) | 14 | 25 | |||
| Age (months) | 21.3 ± 18.9 | 10.2 ± 8.2 | 11.1 | [2.21, 19.99] | 0.01 |
| Weight (kg) | 10.0 ± 4.4 | 8.4 ± 3.2 | 1.6 | [-0.83, 4.03] | 0.10 |
| Survival (n) | 13 | 18 | 0.2086 | [-0.054, 0.471] | 0.12 |
| Death (n) | 1 | 7 | -0.1914 | [-0.454, 0.071] | 0.12 |
| Concurrent Cardiac Malformations (n) | 3 | 7 | -0.1029 | [-0.324, 0.118] | 0.65 |
| Surgery Duration (min) | 147.2 ± 44.6 | 177.1 ± 54.8 | -29.9 | [-56.45, -3.35] | 0.045 |
| Extracorporeal Circulation Time (min) | 56.5 ± 16.9 | 103.9 ± 55.8 | -47.4 | [-66.82, -27.98] | 0.002 |
| T (%) | 53.5 ± 21.7 | 67.5 ± 22.0 | -14.0 | [-26.81, -1.19] | 0.03 |
| T/P Ratio | 0.9 ± 0.5 | 2.9 ± 4.3 | -2.0 | [-3.91, -0.09] | 0.047 |
| Postoperative Ventilator Support Time (h) | 1.2 ± 4.4 | 239.8 ± 400.9 | -238.6 | [-426.82, -50.38] | 0.017 |
| ICU Stay Duration (days) | 4.6 ± 4.6 | 19.6 ± 29.5 | -15.0 | [-25.23, -4.77] | 0.03 |
| Postoperative Hospital Stay (days) | 14.4 ± 8.8 | 28.5 ± 28.2 | -14.1 | [-26.14, -2.06] | 0.039 |
| Postoperative Reintubation (n) | 1 | 1 | 0.67 | ||
| Reoperation Interventions (n) | 0 | 1 | 0.45 |
MD: Mean Difference. RD: Risk Difference. CI: confidence intervals
Overall, the LMA group demonstrated a significantly shorter surgery duration, extracorporeal circulation time, degree of tracheal stenosis (T), T/P ratio, postoperative ventilator support time, ICU stay duration, and postoperative hospital stay duration than the tracheal intubation group. The age at surgery in the LMA group was also significantly older. No significant differences were observed between the two groups in terms of weight, mortality rate, concurrent cardiac malformations, postoperative reintubation, or reoperation rate. There were no cases of intraoperative or postoperative aspiration, nor were there any cases of postoperative pneumonia in the two groups. The substantial variability in postoperative ventilator support time observed in the tracheal intubation group (SD = 400.9 h) may be associated with the inclusion of more complex and severe cases, such as those requiring tracheoplasty (28.2% of the intubation group) or complicated by intracardiac anomalies, which likely contributed to pronounced heterogeneity in postoperative respiratory support requirements.
Because patients undergoing tracheoplasty required longer surgery durations, traditional tracheal intubation was used for respiratory management in these cases. To minimize the influence of tracheoplasty on outcomes, only cases involving left pulmonary artery grafting and concurrent intracardiac malformations were analyzed separately. These patients were divided into the LMA group and the tracheal intubation group, and comparisons were made between the two groups for demographics, surgery type, extracorporeal circulation time, aortic cross-clamp time, degree of tracheal stenosis (T), T/P ratio, postoperative ventilator support time, ICU stay duration, hospital stay duration, and postoperative reinterventions, as shown in Table 3.
Table 3.
Comparison between LMA and tracheal intubation groups in non-tracheoplasty cases
| Variable | LMA Group | Tracheal Intubation Group | MD/RD | 95%CI | P-value |
|---|---|---|---|---|---|
| Number of Cases (n) | 14 | 16 | |||
| Age (months) | 21.3 ± 18.9 | 9.8 ± 6.5 | 11.5 | [2.26, 20.74] | 0.015 |
| Weight (kg) | 10.0 ± 4.4 | 8.0 ± 2.6 | 2.0 | [-0.12, 4.12] | 0.068 |
| Survival (n) | 13 | 11 | 0.2143 | [-0.076, 0.505] | 0.10 |
| Death (n) | 1 | 5 | -0.1786 | [-0.424, 0.067] | 0.10 |
| Concurrent Cardiac Malformations (n) |
3 (3 ASD) |
7 (4 VSD, 3 ASD) |
-0.1607 | [-0.405, 0.084] | 0.196 |
| Surgery Duration (min) | 147.2 ± 44.6 | 161.1 ± 61.6 | -13.9 | [-46.91, 19.11] | 0.245 |
| Extracorporeal Circulation Time (min) | 56.5 ± 16.9 | 85.4 ± 50.0 | -28.9 | [-53.73, -4.07] | 0.024 |
| T (%) | 53.5 ± 21.7 | 59.9 ± 22.5 | -6.4 | [-22.18, 9.38] | 0.218 |
| T/P Ratio | 0.8 ± 0.5 | 2.0 ± 2.5 | -1.2 | [-2.28, -0.12] | 0.045 |
| Immediate postoperative extubation or removal of LMA | 13 | 0 | 0.9286 | [0.748, 1.109] | 0.0000003 |
| Postoperative Reintubation (n) | 1 | 1 | 0.922 | ||
| Postoperative Ventilator Support Time (h) | 1.2 ± 4.4 | 154.6 ± 243.8 | -153.4 | [-286.82, -20.00] | 0.013 |
| ICU Stay Duration (days) | 3.5 ± 3.6 | 9.5 ± 12.5 | -6.0 | [-11.63, -0.37] | 0.047 |
| Postoperative Hospital Stay (days) | 14.4 ± 8.8 | 18.7 ± 15.2 | -4.3 | [-11.62, 3.02] | 0.180 |
| Reoperation Interventions (n) | 0 | 1 | 0.341 |
MD: Mean Difference. RD: Risk Difference. CI: confidence intervals
After excluding tracheoplasty cases, the LMA group continued to show a significantly shorter extracorporeal circulation time, T/P ratio, postoperative ventilator support time, and ICU stay duration than the tracheal intubation group. The age at surgery in the LMA group remained significantly older. The only mortality case in the LMA group involved a 7.5-month-old patient without concurrent cardiac malformations and a T/P ratio of 1.9, who underwent only left pulmonary artery grafting without tracheoplasty. This patient required reintubation because of obstructive ventilatory dysfunction and ultimately died of respiratory failure, attributed to limited early diagnostic and treatment experience. In addition, in the remaining cases of the laryngeal mask airway (LMA) group, the LMA was removed immediately after the surgery, the patients were weaned from the ventilator, and then transferred to the ICU while breathing spontaneously, with no requirement for further non-invasive respiratory support.
Although the postoperative mechanical ventilation time in the LMA group was significantly shorter (MD = -238.6 h, 95% CI: -426.8 to -50.4, P = 0.017), it should be noted that this difference was influenced by case complexity. Clinically, patients in the LMA group could undergo immediate postoperative LMA removal, reducing invasive ventilation-related complications, which is practically significant for the rapid rehabilitation of pediatric patients.
Discussion
The successful application of LMA ventilation in pediatric cardiac and thoracic surgeries has been previously reported [2–4]; however, its use in the surgical correction of PAS is unprecedented. Previous studies have shown that patients with PAS undergoing tracheal intubation, even without tracheal reconstruction, often experience extubation difficulties in the ICU, resulting in prolonged mechanical ventilation. LMA ventilation can effectively reduce airway irritation caused by tracheal intubation, and theoretically reduce complications such as laryngitis and tracheal edema, thereby minimizing mucosal edema in the stenotic tracheal segment and preventing postoperative ventilation challenges. Additionally, when combined with ultra-fast track anesthesia, LMA ventilation enables early removal in the operating room, restoring the patient’s spontaneous respiration and airway protective reflexes. This promotes autonomous coughing and expectoration, reduces airway irritation from postoperative suctioning, and decreases the incidence of ventilator-associated pneumonia, ultimately contributing to the rapid rehabilitation of pediatric patients [5–7].
Nevertheless, patients with PAS often present with varying degrees of tracheal stenosis, which can lead to elevated airway pressures during mechanical ventilation. For patients with severe tracheal stenosis or those undergoing tracheoplasty, tracheal intubation can provide airway support and reduce the risk of postoperative tracheomalacia, which is one of the reasons for choosing intubation in such patients in this study. The cuff leak pressure of the LMA typically does not exceed 20–25 cmH2O [8, 9], posing risks of LMA leakage, regurgitation, and aspiration [9]. To address these risks, we routinely perform mask ventilation prior to LMA insertion to evaluate the feasibility of mechanical ventilation. In this study, no patients required conversion from mask ventilation to tracheal intubation due to difficulty. Given our limited experience, we have not yet utilized LMA ventilation for patients with PAS requiring tracheal reconstruction. As absolute contraindications for LMA ventilation include a full stomach or the presence of regurgitation and aspiration risks [10–12], only elective cases with appropriate fasting time and no gastroesophageal reflux disease were included in the LMA group.
Current literature has documented the use of LMA ventilation in adults with tracheal stenosis undergoing reconstruction surgeries [13]. Adiyeke et al. [14] divided adults undergoing tracheal reconstruction surgery into LMA ventilation and tracheal intubation groups, finding that the LMA group had lower ICU admission rates, shorter ICU stays, and a reduced incidence of positive bacterial cultures in tracheal secretions compared with the tracheal intubation group. Considering that the goal of anesthesia management should be to provide adequate oxygenation with the least possible trauma, the researchers recommended LMA ventilation as the preferred method for airway management during tracheal reconstruction surgery [14]. Defosse et al. [15] also supported LMA ventilation as a suitable alternative for airway management during tracheal reconstruction, even for individuals with significant tracheal stenosis. They further noted that LMA ventilation does not obstruct the surgical field or exert pressure on fresh anastomoses [15]. Menna et al. [16] concurred, emphasizing LMA ventilation as a viable option for airway management during tracheal surgery and citing advantages such as a shorter surgery duration, lower ICU admission rates, shorter ICU stays, and a reduced incidence of postoperative dysphonia.
Because of our limited experience, we tend to favor tracheal intubation for anesthesia and respiratory management in surgeries that are more complex and time-consuming. Since our center first employed LMA ventilation for PAS surgery in 2014, we have increasingly adopted this approach for patients with relatively mild PAS. Over the past 5 years, we have also successfully applied LMA ventilation to patients with simple congenital heart defects, such as atrial septal defects and ventricular septal defects, who had good cardiac function and could undergo simultaneous surgery, achieving excellent postoperative recovery. For patients with more severe disease requiring tracheal reconstruction, we continue to use traditional tracheal intubation to ensure surgical safety and effective postoperative care. With accumulated experience, we may eventually consider utilizing LMA ventilation for patients with PAS who require tracheal reconstruction.
In this study, we found that LMA ventilation is particularly suitable for older patients with PAS who have milder tracheal stenosis, lower T/P ratios, and good cardiac function. These patients achieved immediate postoperative removal of LMA and restoration of spontaneous respiration, significantly reducing the need for postoperative mechanical ventilation, ICU stays, and hospitalizations. This approach also substantially reduces nursing challenges and facilitates rapid recovery, consistent with findings in previous literature.
Incorporating our previous research findings, we propose a exploratory and hypothesis-generating sling diagnosis and treatment model that warrants further validation and exploration. Patients with PAS typically present with symptoms such as wheezing, dyspnea, and respiratory distress. Enhanced cardiac computed tomography and echocardiography can confirm the diagnosis, assess the presence of concomitant congenital heart defects, and evaluate cardiac function. The severity of tracheal stenosis (T), the severity of left pulmonary artery stenosis (P), and the T/P ratio should then be measured and calculated. For patients with T/P ratios of < 1.15, left pulmonary artery reimplantation surgery alone may be considered. If the patient is older, with or without simple congenital heart defects and good cardiac function, LMA ventilation can be considered for intraoperative respiratory management to enable immediate postoperative removal of LMA and restoration of spontaneous ventilation. For patients with T/P ratios of > 1.15, concurrent left pulmonary artery reimplantation and slide tracheoplasty should be considered, with tracheal intubation as the primary ventilation method. The surgical technique for slide tracheoplasty can follow the approach described by Du et al. [17]. Additionally, for patients with concomitant simple congenital heart defects, such as atrial septal defects or ventricular septal defects, and good cardiac function requiring simultaneous surgery, LMA ventilation can safely and effectively facilitate the procedure. For patients with complex congenital heart defects, tracheal intubation remains the preferred option because of potential cardiac function impairments. The diagnosis and treatment model proposed in this study is an exploratory hypothesis. Given that it is based on the experience of a single center, its predictive value for postoperative outcomes requires verification through multi-center studies.
In this study, LMA® Unique™, a first generation LMA was used in all patients and the size was depended on the weight of the patients, size 1 for the patients less than 5 kg and size 1.5 for those between 5 and 10 kg. The first generation LMA was used because we were more familiar with it than other newer devices and we thought it safer to use a familiar device than a new but unfamiliar one in this complex surgery. However, the newer supraglottic devices which imporved the airway leak pressure may offer higher airway pressure when ventilating intaropartively, which makes it possible to ventilate the patients with sever treachal stenosis. The further study is warranted to confirm the safety and the benefits of these newer devices in this setting.
This study primarily aimed to verify the feasibility of laryngeal mask airway (LMA) ventilation in mild cases of pulmonary artery sling, as evidenced by successful intraoperative ventilation and early postoperative removal of LMA. Although multiple comparisons were not corrected, the significance of the primary outcome (P < 0.05) provides preliminary evidence for the feasibility of LMA. Due to the retrospective design, significant differences in baseline characteristics (such as age and degree of tracheal stenosis) were observed between the LMA group and the tracheal intubation group, which may confound the causal inference of the results. Prospective studies or propensity score matching analyses are required for further validation in the future. However, the safety aspects, such as the risk of aspiration and long-term airway complications, require further evaluation through larger-scale samples and long-term follow-up. Although aspiration or pneumonia did not occur in either group, the safe use of LMA still depends on rigorous preoperative airway assessment. The sample size was relatively small (n = 39), especially the LMA group with only 14 cases, which may lead to insufficient power in detecting rare events (such as reintubation).
Limitations
This study has the following limitations: (1) The relatively small sample size (n = 39) may result in insufficient detection power for rare outcomes (such as reintubation, n = 2), entailing a risk of type II error. (2) Due to the retrospective design, selection bias cannot be completely eliminated. Patients in the LMA group tended to be older and have milder tracheal stenosis, which may affect the causal inference of the results. (3) The conclusions drawn from a single-center experience have limited generalizability. Variations in surgical and anesthetic strategies across different medical centers may influence the application effectiveness of LMA. (4) Only the first-generation LMA was used in this study, and the efficacy of new devices remains unvalidated.
Conclusion
LMA ventilation is a feasible and effective option for respiratory management during surgery in select patients with PAS, particularly those who are older, have milder symptoms, exhibit less severe tracheal stenosis, have lower T/P ratios, and may or may not have simple congenital heart defects with good cardiac function. LMA ventilation was associated with shorter ICU and hospital stays, suggesting it may serve as a reasonable alternative for selected children with pulmonary artery sling (PAS). This study firstly explores the feasibility of laryngeal mask airway (LMA) in pulmonary artery sling (PAS) surgery, and finds that LMA can safely replace tracheal intubation in specific cases, providing a new approach for airway management of such patients.
Acknowledgements
We thank Angela Morben, DVM, ELS, from Liwen Bianji (Edanz) (www.liwenbianji.cn) for editing the English text of a draft of this manuscript.
Author contributions
Xiao Shen: Conceptualization, Data curation, Formal analysis, Writing - Original Draft.Fan Zhang: Methodology, Investigation, Writing - Review & Editing.HuiFeng Zhang: Supervision, Project administration.Ming Ye: Resources, Validation.Xiao Shen and Fan Zhang are co-first authors.HuiFeng Zhang and Ming Ye are co-corresponding authors.All authors have read and agreed to the published version of the manuscript.
Funding
This study is supported by the fund of the National Clinical Key Specialty Construction Project (no.10000015Z155080000004).
Data availability
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.
Declarations
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Xiao Shen and Fan Zhang contributed equally to this work.
Contributor Information
HuiFeng Zhang, Email: zhanghuifeng@fudan.edu.cn.
Ming Ye, Email: xiaox1106@163.com.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.