Incidence of gastric insufflation at high compared with low laryngeal mask cuff pressure: A randomised controlled cross-over trial

Efficacy and safety of three inflation methods of the laryngeal mask airway Ambu® Auraonce™: a randomized controlled study

The laryngeal mask airway (LMA) is commonly used for airway management. Cuff hyperinflation has been associated with complications, poor ventilation and increased risk of gastric insufflation. This study was designed to determine the best cuff inflation method of AuraOnce™ LMA during bronchoscopy and EBUS (Endobronquial Ultrasound Bronchoscopy) procedure. We designed a Randomized controlled, doble-blind, clinical trial to compare the efficacy and safety of three cuff inflation methods of AuraOnce™ LMA. 210 consenting patients scheduled for EBUS procedure under general anesthesia, using AuraOnce™ LMA were randomized into three groups depending on cuff insufflation: residual volume (RV), half of the maximum volume (MV), unchanged volume (NV). Parameters regarding intracuff pressure (IP), airway leak pressure (OLP), leakage volume (LV) were assessed, as well as postoperative complications (PC). 201 (95.7%) patients completed the study. Mean IP differed between groups (MV: 59.4 ± 32.4 cm H2O; RV: 75.1 ± 21.1 cm H2O; NV: 83.1 ± 25.5 cmH20; P < 0.01). The incidence of IP > 60 cmH2O was lower in the MV group compared to the other two (MV: 20/65(30.8%); RV:47/69 (68.1%); NV 48/67 (71.6%); p < 0.01). The insertion success rate was 89,6% (180/201) at first attempt, with no difference between groups (p = 0.38). No difference between groups was found either for OLP (p = 0.53), LV (p = 0.26) and PC (p = 0.16). When a cuff manometer is not available, a partial inflation of AuraOnce™ LMA cuff using MV method allows to control intracuff pressure, with no significant changes of OLP and LV compared to RV and NV insufflation method.Registration clinical trial: NCT04769791.

Efficacy of using an intravenous catheter to repair damaged expansion lines of endotracheal tubes and laryngeal masks

Background

 In perioperative care or intensive care units, the expansion lines of endotracheal tubes (ETTs) or laryngeal mask airways (LMAs) may be accidentally cut off during medical procedures. We designed a simple method for repairing damaged ETT and LMA expansion lines.

Methods

 In this in vitro study, ETT (n = 20) or LMA (n = 20) models were each categorized into experimental (n = 10) and control (n = 10) groups. In the experimental groups, the expansion lines were cut in the middle, and a 22G intravenous catheter was inserted into the broken end of each expansion line. The time taken to repair the expansion lines was recorded in both experimental groups. The repaired expansion lines in both groups were tested for visible underwater air leakage with cuffs under high pressure (120 cm H2O). After 15 h, the cuff pressure and tensile strength of the expansion lines were measured.

Results

 The overall time required to repair the expansion line was 27.8 ± 1.5 s in the ETT group and 20.4 ± 1.1 s in the LMA group. When the cuff pressure was increased to 120 cmH₂O, no air leakage was observed in the experimental LMA and ETT groups. The mean difference in the cuff pressures of the control and experimental groups was insignificant for both, ETT (9.50 ± 1.29 vs. 9.50 ± 1.08 cmH₂O, 95% CI =  − 1.11 to 1.11 cmH₂O, P = 1.00) and LMA (34.1 ± 1.10 cmH₂O vs. 34.5 ± 0.97 cmH₂O, 95% CI =  − 0.57 to 1.37 cmH₂O, P = 0.40) groups, The tensile strength and the force required to pull apart the expansion lines in the experimental groups were lower than those in the control groups for ETTs (3.32 ± 0.37 N vs. 35.03 ± 4.47 N, 95% CI =  − 34.69 to − 28.72 N, P < 0.0001) and LMAs (36.55 ± 2.20 N vs. 26.18 ± 1.67 N, 95% CI =  − 12.21 to − 8.53 N, P < 0.0001).

Conclusion

 An intravenous catheter can be directly inserted into the damaged ETT or LMA expansion lines; it is a simple, rapid, and effective repair method.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01776-5.

Severe gastric insufflation and consequent atelectasis caused by gas leakage using AIR-Q laryngeal mask airway: A case report

BACKGROUND

The airways of patients undergoing awake craniotomy (AC) are considered “predicted difficult airways”, inclined to be managed with supraglottic airway devices (SADs) to lower the risk of coughing or gagging. However, the special requirements of AC in the head and neck position may deteriorate SADs’ seal performance, which increases the risks of ventilation failure, severe gastric insufflation, regurgitation, and aspiration.

CASE SUMMARY

A 41-year-old man scheduled for AC with the asleep–awake–asleep approach was anesthetized and ventilated with a size 3.5 AIR-Q intubating laryngeal mask airway (LMA). Air leak was noticed with adequate ventilation after head rotation for allowing scalp blockage. Twenty-five minutes later, the LMA was replaced by an endotracheal tube because of a change in the surgical plan. After surgery, the patient consistently showed low tidal volume and was diagnosed with gastric insufflation and atelectasis using computed tomography.

CONCLUSION

This case highlights head rotation may cause gas leakage, severe gastric insufflation, and consequent atelectasis during ventilation with an AIR-Q intubating laryngeal airway.

Pharyngolaryngeal Morbidity With the Laryngeal Mask Airway SupremeTM at Different Fiberoptic Bronchoscopy Grades: An Observational Study

OBJECTIVE

To assess whether the different fiberoptic bronchoscopy (FOB) grades of laryngeal mask airway (LMA) Supreme™ affects pharyngolaryngeal morbidity (PLM, including sore throat, dysphonia, pharyngoxerosis, and dysphagia) after general anesthesia.

METHODS

A total of 235 adult patients scheduled for elective laser lithotripsy undergoing general anesthesia with the placement of LMA Supreme™ were enrolled. The position of LMA Supreme™ was assessed by FOB and categorized into five grades. Meanwhile, patients were divided into four groups (grades A-D); none was assessed as grade E. We collected blinded data on PLM at 2 (H+2), 6 (H+6), and 24 hours (H+24) postoperatively. The incidence and severity of PLM as the primary outcome and incidence of PLM at three time points as a secondary outcome were compared.

RESULTS

The incidence of PLM was higher at 2 and 6 hours than at 24 hours; however, no significant difference was found between the incidence of PLM in the FOB groups. Furthermore, the severity of sore throat and dysphonia between groups were obviously differed at H+6 and H+24, but similar at H+2. The severity of postoperative pharyngoxerosis and dysphagia were similar between groups at three time points.

CONCLUSIONS

A positive association was found between the severity of postoperative sore throat and dysphonia and FOB grade after LMA Supreme™ placement. PLM secondary to placement of the LMA Supreme™ was short lasting.