Comparison of the AMBU® Laryngeal Mask and the LMA Classic in Anaesthetised, Spontaneously Breathing Patients

Laryngeal mask general anaesthesia versus spinal anaesthesia for promoting early recovery of cervical conisation: A randomised, controlled clinical study

Background

Although both spinal and general anaesthesia provides good anaesthesia for cervical conization, spinal anaesthesia delays the return of lower limb movements and urinary function, whereas general anaesthesia requires the patient to be unconscious. It is unclear which anaesthetic technique is more conducive to early postoperative recovery in patients undergoing cervical conization.

Patients and methods

140 patients undergoing cervical conization underwent either laryngeal mask general anaesthesia (LMA, n = 70) or spinal anaesthesia (SA, n = 70). In the LMA group, an i-gel mask was used for airway management. In the SA group, spinal anaesthesia was received with 0.75% ropivacaine (15 mg) in the L3-4 interval. The quality of recovery score (QoR-15) was the primary endpoint of the study. Secondary endpoints included incidence of adverse 24-h analgesia (NRS>3); return of lower limb activity; first bed activity and feeding; and the number of catheters removed at 6, 12 and 24 h postoperatively.

Result

The LMA group significantly improved QoR-15 scores (136.62 ± 11.02 vs 119.97 ± 12.75; P < 0.001); and reduced the incidence of poor analgesia (NRS >3) within 24 h postoperatively (20% vs 42.8%, P = 0.006); reduced time in bed (15.62 ± 3.83 h vs 18.27 ± 5.57 vs, P = 0.001); improved patient satisfaction (86% vs 27%; P < 0.001); and catheters removal within 24 h (70/70 vs 42/70, P < 0.001).

Conclusion

LMA general anaesthesia can facilitate early postoperative recovery in patients undergoing cervical conization compared with conventional spinal anaesthesia.

Trial registration

Chinese Clinical Trial Registry (ID: ChiCTR1800019384), http://www.chictr.org.cn/listbycreater.aspx (08/11/2018).

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

BACKGROUND

The success of ventilation with a laryngeal mask depends crucially on the seal between the mask and the periglottic tissue. Increasing the laryngeal mask's cuff volume is known to reduce oral air leakage but may lead to gastric insufflation.

OBJECTIVE

We hypothesised that a lower cuff pressure would result in less gastric insufflation. We sought to compare gastric insufflation with laryngeal mask cuff pressures of 20 cmH2O (CP20) and 60 cmH2O (CP60) during increasing peak airway pressures in a randomised controlled double-blind cross-over study. We also evaluated the incidence of gastric insufflation at the recommended peak airway pressure of 20 cmH2O or less and during both intermittent positive airway pressure and continuous positive airway pressure.

METHODS

After obtaining ethics approval and written informed consent, 184 patients ventilated via laryngeal mask received a stepwise increase in peak airway pressure from 15 to 30 cmH2O with CP20 and CP60 in turn. Gastric insufflation was determined via real-time ultrasound and measurement of the cross-sectional area of the gastric antrum. The primary endpoint was the incidence of gastric insufflation at the different laryngeal mask cuff pressures.

RESULTS

Data from 164 patients were analysed. Gastric insufflation occurred less frequently at CP20 compared with CP60 (P < 0.0001). Gastric insufflation was detected in 35% of cases with CP20 and in 48% with CP60 at a peak airway pressure of 20 cmH2O or less. Gastric insufflation occurred more often during continuous than during intermittent positive airway pressures (P < 0.01).

CONCLUSION

A laryngeal mask cuff pressure of 20 cmH2O may reduce the risk of gastric insufflation during mechanical ventilation. Surprisingly, peak airway pressure of 20 cmH2O or less may already induce significant gastric insufflation. Continuous positive airway pressure should be avoided due to an increased risk of gastric insufflation.

CLINICAL TRIAL REGISTRATION

The study was registered in the German Clinical Trials Register (DRKS00010583) https://www.drks.de.

The AMBU® Aura-i™ Laryngeal Mask and LMA Supreme™: A Randomized Trial of Clinical Performance and Fibreoptic Positioning in Unparalysed, Anaesthetised Patients by Novices

Introduction. Manikin studies' data cannot accurately be extrapolated to real-life scenarios and inherent differences in design and materials of newer products may affect their clinical performance. Methods. Hence, we compared the AMBU® Aura-i™ and LMA Supreme™ in this randomized trial involving 100 ASA 1-2 unparalysed anaesthetised patients undergoing minor gynaecological surgery. Investigators had <20 Aura-i insertions. Primary outcome was time to achieve effective ventilation and secondarily insertion parameters, oropharyngeal leak pressures (OLP), fibreoptic positioning, and pharyngeal morbidity. The position of the Ambu Aura-i was evaluated with the Ascope; the fiberoptic view of the glottis was scored on a five-point scale. Results. 43 (86%) AMBU Aura-i and 44 (88%) LMA Supremes were successfully inserted on first attempt (p = 0.59), with similar ease (p = 0.79), and comparable times to first capnogram, mean (SD) 18.2 (6.0) versus 17.3 (6.4) sec, p = 0.9. The Aura-i needed significantly less volume of air to inflate its cuff to 60 cmH₂O on the manometer, 17.7 (3.5) versus 23.1 (4.4) mL, p < 0.001. Both devices exhibited similar OLP, Aura-i versus LMA Supreme, mean (SD) 28.8 (7.1) versus 27.3 (5.3) cmH₂O, p = 0.24. There was no difference in ease of insertion or adjustment manoeuvres to aid ventilation. 90% of patients had good positioning of Aura-i on fibreoptic check, yielding a view of the vocal cords and epiglottis. In 5 patients (10%), the vocal cords were not seen, but ventilatory function was unaffected. Conclusions. The Aura-i handled well in novices hands, with comparable times to insert and establish ventilation, similar leak pressures, and successful first attempt insertion rates compared to the LMA Supreme.

Comparison of classic laryngeal mask airway with Ambu laryngeal mask for tracheal tube exchange: A prospective randomized controlled study

Background and Aim:

Exchanging endotracheal tube (ETT) with classic laryngeal mask airway™ (CLMA™) prior to emergence from anaesthesia is a safe technique to prevent the coughing and haemodynamic changes during extubation. We had compared CLMA™ and AMBU laryngeal mask™ (ALM™) during ETT/laryngeal mask (LM) for haemodynamic changes and other parameters.

Methods:

A total of 100 American Society of Anesthesiologist Grade I and II adult female patients undergoing elective laparoscopic cholecystectomy under general anaesthesia were selected and randomly divided into two groups of 50 patients each. In Group I, CLMA™ and in Group II, ALM™ was placed prior to tracheal extubation. Haemodynamic parameters were recorded during ETT/LM exchange. Glottic view was seen through the LM using flexible fibrescope. Coughing/bucking during removal of LM, ease of placement and post-operative sore throat for both groups were graded and recorded.

Statistical Analysis:

Data within the groups was analysed using paired t-test while between the groups was analysed using unpaired t-test. Chi-square test was used to analyse grades of glottic view, coughing, and post-operative sore throat.

Results:

In Group I, there was a significant rise in systolic blood pressure and heart rate in contrast to insignificant rise in Group II. Glottis view was significantly better in Group II. Incidence of coughing, ease of placement and post-operative sore throat was identical between both groups.

Conclusion:

ALM™ is superior to CLMA™ for exchange of ETT before extubation due to greater haemodynamic stability during exchange phase and is better positioned.

Randomised Comparison of the AMBU AuraOnce Laryngeal Mask and the LMA Unique Laryngeal Mask Airway in Spontaneously Breathing Adults

We conducted a randomised single-blind controlled trial comparing the LMA-Unique (LMAU) and the AMBU AuraOnce (AMBU) disposable laryngeal mask in spontaneously breathing adult patients undergoing general anaesthesia. Eighty-two adult patients (ASA status I–IV) were randomly allocated to receive the LMAU or AMBU and were blinded to device selection. Patients received a standardized anesthetic and all airway devices were inserted by trained anaesthetists. Size selection was guided by manufacturer recommendations. All data were collected by a single, unblinded observer. When compared with the LMAU, the AMBU produced significantly higher airway sealing pressures (AMBU 20 ± 6; LMAU 15 ± 7 cm H₂O; P = 0.001). There was no statistical difference between the two devices for overall success rate, insertion time, number of adjustments, laryngeal alignment, blood-staining, and sore throat (P ≥ 0.05). The AMBU AuraOnce disposable laryngeal mask provided a higher oropharyngeal leak pressure compared to the LMA Unique in spontaneously breathing adult patients.