High Success Rate of Fiberscope-Monitored Intubation via a Supraglottic Airway Device BlockBusterTM in Good Device Positioning: A Prospective Observational Study
Airway management is a critical aspect of anesthesia, directly impacting patient safety and the quality of care. In 2015, the Difficult Airway Society emphasized the importance of fiberoptic bronchoscope (FOB)-guided endotracheal intubation, recommending against blind intubation techniques. The supraglottic airway device (SAD) BlockBusterTM, coupled with its matched tracheal tube (BlockBusterTM tracheal tube, BTT), represents an advanced second-generation SAD designed for intubation. This study explores the feasibility, success rate, and complications associated with fiberscope-monitored intubation via the SAD BlockBusterTM in patients with well-positioned devices.
The study enrolled 106 patients classified as American Society of Anesthesiology (ASA) Grades 1 and 2, aged between 20 and 65 years, who were scheduled for elective surgery at Beijing Friendship Hospital from January to October 2020. Exclusion criteria included patient refusal, asthma, cervical instability, mouth opening less than 3 cm, severe obstructive sleep apnea syndrome, or allergies to intravenous anesthetics. The study received ethical approval, and informed consent was obtained from all participants.
Upon arrival in the operating room, patients were equipped with standard multi-channel monitors, including non-invasive blood pressure, electrocardiograph, pulse oxygen saturation, and end-tidal carbon dioxide (ETCO2) waveforms. Patients were pre-oxygenated with 100% oxygen for 3 minutes, followed by anesthesia induction using midazolam, sufentanil, and etomidate. Neuromuscular blockade was achieved with cisatracurium, after which the SAD BlockBusterTM was inserted into the upper airway. The device’s cuff was inflated to an intracuff pressure of 30–40 cm H2O, and mechanical ventilation was initiated.
A flexible fiberscope with a 4.0 mm external diameter was passed through the SAD to assess its positioning. The fiberscopic view was graded as follows: Grade 1, only the glottis visible; Grade 2, vocal cords and posterior epiglottis visible; Grade 3, vocal cords and anterior epiglottis visible; and Grade 4, vocal cords not visible. Grades 1 and 2 were considered suitable for fiberscope-monitored tracheal intubation, while Grade 3 required device adjustment. Intubation was discontinued in Grade 4 cases due to poor positioning.
The appropriate size of BTTs was selected based on the SAD size, with 6.5 mm and 7.0 mm internal diameter tubes used for No. 3 and No. 4 SADs, respectively. The BTT was inserted into the SAD’s airway channel, and the fiberscope was advanced through the BTT to visualize the glottis. The tracheal tube was then delivered into the trachea, and the cuff was inflated to 25 cm H2O. The SAD BlockBusterTM remained in place with the cuff deflated until the end of anesthesia, at which point it was removed along with the tracheal tube. If the procedure was unsuccessful, intubation was performed using a Macintosh laryngoscope. A lubricated gastric tube was inserted via the drainage channel, and the success rate was recorded.
Data collected included the number of attempts and time required for SAD BlockBusterTM insertion, fiberscopic assessment of SAD positioning using the Brimacombe J scoring system, success rate of fiberscope-monitored intubation, number of attempts and time needed for BTT intubation, and postoperative airway trauma and complications. Statistical analysis was performed using SPSS software, with continuous variables expressed as mean ± standard deviation and categorical variables as percentages. Comparisons were made using Student’s t-test, Chi-squared test, or Fisher’s exact test, with a p-value <0.05 considered statistically significant.
All 106 patients were successfully inserted with the SAD BlockBusterTM on the first attempt, with normal ventilation function. Four patients exhibited blood staining on the device, and six reported sore throats, although no complaints were noted 3 hours post-operation. The sex ratio was 70 females to 36 males, the SAD insertion time was 17.0 ± 2.9 seconds, and the gastric tube insertion success rate was 99.1%. Five patients abandoned tracheal intubation due to poor SAD positioning, while 101 patients were successfully intubated. The intubation attempts, success rates, and time required for each fiberscopic view grade are detailed in Table 1.
In a comparison with other studies, Sood et al. reported a first intubation success rate of 96.7% with the i-gel and 93.3% with the LMA FastrachTM, with intubation times of 69.5 ± 5.1 seconds and 72.3 ± 6.7 seconds, respectively. In this study, the first fiberscope-monitored intubation success rate was 96.0%, with intubation time approximately one-third of that reported by Sood et al. The higher success rate and shorter intubation time with the SAD BlockBusterTM may be attributed to its unique design, including a short, curved airway channel with a large oval cavity and a circular exit with a ramp, as well as a modified inflatable cuff. The dedicated BTT, a reinforced tube, is recommended for use with the SAD BlockBusterTM.
The advantages of monitored intubation over guided intubation include the ability to observe the entire process of tube entry into the glottis and trachea, allowing for timely detection of issues. This technique is also simpler and quicker, requiring less complex training. All patients in this study were successfully inserted with the SAD BlockBusterTM, with normal ventilation function, consistent with findings from Wan et al. The insertion time of 17.0 ± 2.9 seconds was similar to that reported by Zhou. Gao et al. found that the rate of good view and satisfactory positioning of the SAD BlockBusterTM was significantly higher than that of the LMA Supreme.
In this study, all fiberscope-monitored endotracheal intubations through the SAD BlockBusterTM with good fiberscopic views were successful on the first attempt, indicating that glottic fiberscopic view quality significantly affects intubation success. Three patients with Grade 3 fiberscopic views required BTT rotation under fiberscope monitoring and were successfully intubated on the second attempt. In one case, the fiberscopic view grade improved to Grade 2 with a jaw-lift maneuver, allowing for successful intubation on the third attempt. These results suggest that endotracheal intubation via the SAD BlockBusterTM is feasible under fiberscope monitoring when the fiberscopic view grade is 1–3.
Endigeri et al. noted a reduction in complications such as sore throat with the SAD BlockBusterTM, attributed to its close fit with the oropharyngeal curve. The BTT’s centered and bendable tip facilitates easy passage into the glottis and trachea, minimizing subglottic mucosal damage. In this study, four patients had blood staining on the SAD, and six reported sore throats post-removal, all with normal airways. Females comprised approximately 66.0% of the study population, providing valuable clinical reference.
In conclusion, fiberscope-monitored intubation via the SAD BlockBusterTM using the BTT is effective and reliable when the fiberscopic glottis view of the device position is good. The entire intubation process is visible, straightforward, and quick, with minimal airway irritation and damage. The study highlights the importance of device positioning and the benefits of monitored intubation in ensuring successful airway management.
doi.org/10.1097/CM9.0000000000002938
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