Repeat autoclaving does not remove protein deposits from the classic laryngeal mask airway

Airway management for anaesthesia in the ambulatory setting

PURPOSE OF REVIEW

The number of anaesthetic procedures in the ambulatory setting is steadily increasing. During the last years, more and more patients with complex medical conditions undergo ambulatory interventions. This review will focus on airway management practices, but especially on techniques used in the ambulatory setting. It will highlight recent literature published in the focus of ambulatory anaesthesia and will discuss relevant findings of the last year.

METHODS

Literature search and analysis performed independently by two reviewers.

RECENT FINDINGS

Practical points to improve success of anaesthesia and to avoid complications in the ambulatory setting are provided. In addition to concepts for the (un)expected difficult airway, new supraglottic devices, and modern concepts for teleconsultation, are discussed.

SUMMARY

There are several points which should be considered for ambulatory anaesthesia. Selected patient groups (e.g., obstructive sleep apnoea, obesity) may have a higher anaesthesia-related risk. To handle the more and more complex conditions in a growing number of ambulatory patients, straightforward concepts, especially for the (un)expected difficult airway, are required.

The effect of high concentration potassium permanganate on protein contamination from metallic and synthetic rubber airway equipment

We tested the hypothesis that supplementary cleaning using potassium permanganate 8 mg.l(-1) eliminates protein deposits from the reusable metallic and synthetic rubber airway equipment. Twenty Macintosh laryngoscope blades (surgical steel), 20 pairs of Magill's forceps (surgical steel) and 20 Guedel airways (synthetic rubber) were allocated to two groups for supplementary cleaning. In group A, the device was immersed in potassium permanganate 8 mg.l(-1). In group B (controls), the device was immersed in sterile water. The devices were then immersed in a protein staining solution, rinsed and the severity of staining was scored. In addition, the devices were inspected for tissue and then tested for occult blood. Protein contamination was lower in the potassium permanganate group for all devices (each device: p < 0.0001). There was no staining detected in the permanganate group. In the permanganate group, dried tissue was detected in the teeth of one pair of forceps, which was not detected following supplementary cleaning. Additionally, occult blood was detected on two pairs of forceps and a laryngoscope blade, which was not detected following supplementary cleaning. In the control group, no tissue was detected but one pair of forceps and two laryngoscope blades tested positive for occult blood before and after supplementary cleaning. We conclude that supplementary cleaning using potassium permanganate 8 mg.l(-1) eliminates protein deposits from re-usable metallic and synthetic rubber airway equipment.

Comparison of the single use and reusable intubating laryngeal mask airway

We compared the times to intubate the trachea using the single use (Group S) and reusable (Group C) intubating laryngeal mask (ILMA(TM)), in 84 healthy patients with normal airways undergoing elective gynaecological surgery. There was no significant difference in the ease of insertion of the ILMA or the tracheal tube, or time to successful insertion (Group S, 101.4 s (SD 63.2) vs Group C, 90.4 s (SD 46.1), p = 0.366). The ILMA was successfully inserted on first attempt in 63% of Group S patients and in 68% of Group C patients. After one or two attempts the overall success rate for both groups was 93%. There was a failure to insert the ILMA in two patients in each group. There was no difference in side-effects (desaturation S(p)o(2) < 95%, bleeding, oesophageal intubation, lip, dental or mucosal injury, or sore throat postoperatively). We conclude that the disposable ILMA is an acceptable alternative to the reusable ILMA.

Masques laryngés à usage unique vs réutilisable : une étude de minimisation de coûts

JUSTIFICATION

According to French regulations concerning the risk of Creutzfeldt-Jakob disease transmission, traceability procedures of all sterile medical devices which need to be reused are mandatory. Despite sterilization processes, the reusable laryngeal mask airway (LMA) prion disease transmission remains possible. As a result, the disposable LMA has been introduced.

OBJECTIVE

Assuming clinical equivalence was achieved, the cost of disposable vs reusable LMA was studied in a university hospital.

STUDY DESIGN

A Cost-minimization analysis of disposable vs reusable laryngeal mask airway was realised.

METHODS

Disposable LMA cost was calculated as the sum of product cost and elimination cost. Reusable LMA were autoclaved after hospital purchasing in two separate sterilizing processing units of the same hospital. Reusable LMA cost was determined combining materiel and labor costs.

RESULTS

The reusable LMA cost depended on the sterilizing processing unit concerned and varied between 9.59 Euros and 9.69 vs 8.38 Euros for the single-use LMA.

CONCLUSION

With the cost savings made possible by use of disposable LMA in both labor and consumables, this practice should be considered.

High concentration potassium permanganate eliminates protein and particle contamination of the reusable Classictm laryngeal mask airway

In this three-stage study, we test the hypothesis that supplementary cleaning with potassium permanganate > or =4 mg.l(-1) eliminates protein and particle contamination from the reusable Classic laryngeal mask airway. The first stage involved supplementary cleaning of 70 1 x 1 cm segments from deliberately contaminated laryngeal mask airways using potassium permanganate at 0, 2, 4, 8, 16, 32 and 64 mg.l(-1) and testing for protein staining. This showed that the lowest concentration required to eliminate protein contamination was 8 mg.l(-1). The second stage involved supplementary cleaning of 50 used laryngeal mask airways with either potassium permanganate 8 mg.l(-1) or saline and testing for protein staining. This showed that protein contamination was lower in the potassium permanganate group (p < 0.00001): all laryngeal mask airways in the control group and none in the potassium permanganate group were contaminated. The third stage involved scanning electron microscopic examination of 1 x 1 cm segments from three laryngeal mask airways used in the control group, three from the potassium permanganate group, plus three brand new laryngeal mask airways. The mean density of > or =1 mum surface particles was lower in the potassium permanganate 8 mg.l(-1) than the control group (21 vs. 121 .cm(-2), p < 0.0001) and was similar to brand new laryngeal mask airways (24 .cm(-2)). We conclude that supplementary cleaning with potassium permanganate 8 mg.l(-1) eliminates protein deposits from reusable laryngeal mask airways and reduces particle contamination to similar levels to brand new laryngeal mask airways.

Supraglottic airway devices

Supraglottic airway devices are developed with increasing frequency following the overwhelming success of the laryngeal mask airway (LMA). Currently, the LMA, the ProSeal laryngeal mask airway (PLMA), the laryngeal tube (LT), the laryngeal tube with integrated suctioning tube (LTS) and the oesophageal tracheal combitube (OTC) are the best evaluated and most widespread devices. Both the LMA and the PLMA have been shown to be perfectly suitable for routine anaesthesia and emergency airway management. While the LMA is limited by the lack of reliable protection against aspiration, the value of the PLMA in this respect remains undetermined yet. LT and LTS are primarily intended as emergency airway devices, but have also been successfully used during controlled ventilation in adults. The OTC, though advocated for emergency as well as routine use, is limited by high airway morbidity and possible serious complications.