Association of Mallampati scoring on airway outcomes in women undergoing general anesthesia with Supreme™ laryngeal mask airway in cesarean section

The role of supraglottic airway devices for caesarean section under general anaesthesia. A scoping literature review with a proposed algorithm for the appropriate use of supraglottic airway devices for caesarean sections

This review aims to assess the published evidence on airway management with a supraglottic airway device (SGA) for general anaesthesia in patients requiring a caesarean section. Physiological changes during pregnancy can make airway management in parturients challenging. At the same time, pregnant patients are at risk of pulmonary aspiration due to hormonal and mechanical alterations. The standard airway management for parturients undergoing caesarean section is rapid sequence induction followed by tracheal intubation. Evidence exists that using second-generation SGA devices is well tolerated and effective in selected patients. In this review, we provide an overview of the existing evidence and provide an algorithm to make an evidence-based clinical decision on the use of SGA devices. An online literature search was performed in Medline, Embase, PubMed, Emcare, Cochrane Library and CINAHL. The search terms used were 'supraglottic airway', 'supraglottic airway device', 'supraglottic airway management', 'supraglottic tube', 'i-gel', laryngeal mask', 'laryngeal mask airway', 'LMA', 'SGA', 'Proseal', 'Supreme', 'obstetric surgery', 'obstetric operation', 'general anaesthesia', 'caesarean' or 'caesarean section', 'abdominal delivery'. Full-text articles in English, Dutch and French were included. Case reports and studies in which the surgery was not a caesarean section were excluded. The initial search yielded 815 results. Following screening, deduplication and removal of publications that were unrelated to the topic or did not fit the inclusion criteria, 13 manuscripts were included in our analysis. A total of 7722 patients were described in the articles included. In the majority of manuscripts, second-generation SGA devices were used. There were seven cases of failed insertion and a need for conversion to tracheal intubation; first-generation SGA devices were used in these cases. There were no cases of pulmonary aspiration, and only one case of gastric regurgitation was described. Growing evidence suggests that the use of second-generation SGA devices might be well tolerated as the primary method for securing the airway for caesarean sections requiring general anaesthesia, in selected patients with a low risk for aspiration and difficult intubation.

The role of supraglottic airway devices in obstetric anaesthesia

PURPOSE OF REVIEW

To discuss the role of supraglottic airway devices as rescue and primary airway devices in pregnant patients.

RECENT FINDINGS

General anaesthesia in pregnant patients is associated with increased incidence of difficult and failed intubation, especially when performed for caesarean deliveries. The Difficult Airway Society and the Obstetric Anaesthetists' Association guidelines for the management of failed intubation recommend the use of second-generation supraglottic airway devices as a rescue airway strategy when failed intubation occurs. This practice is now widely accepted and embedded in routine teaching and clinical practice. On the other hand, there is little but growing evidence describing the use of supraglottic airway devices as the primary airway device and an alternative to endotracheal intubation for patients undergoing elective and emergency caesarean deliveries under general anaesthesia. Most of the published research supporting this practice was done on carefully selected patients who were nonobese and who did not have gastroesophageal reflux or anticipated difficult airway. Despite demonstrating high insertion success rates and low complication rates, these studies were underpowered and have thus far, failed to provide robust data on the true risk of aspiration in this setting.

SUMMARY

Based on current scientific data, the evidence for the safe use of supraglottic airway devices as primary airway devices during general anaesthesia for caesarean deliveries is not compelling. However, their use as rescue airway devices remains a well established strategy supported by international guidelines.

The effects of labor on airway outcomes with Supreme™ laryngeal mask in women undergoing cesarean delivery under general anesthesia: a cohort study

BACKGROUND

Pregnancy is associated with higher incidence of failed endotracheal intubation and is exacerbated by labor. However, the influence of labor on airway outcomes with laryngeal mask airway (LMA) for cesarean delivery is unknown.

METHODS

This is a secondary analysis of a prospective cohort study on LMA use during cesarean delivery. Healthy parturients who fasted > 4 h undergoing Category 2 or 3 cesarean delivery with Supreme™ LMA (sLMA) under general anesthesia were included. We excluded parturients with BMI > 35 kg/m2, gastroesophageal reflux disease, or potentially difficult airway (Mallampati score of 4, upper respiratory tract or neck pathology). Anesthesia and airway management reflected clinical standard at the study center. After rapid sequence induction and cricoid pressure, sLMA was inserted as per manufacturer's recommendations. Our primary outcome was time to effective ventilation (time from when sLMA was picked up until appearance of end-tidal carbon dioxide capnography), and secondary outcomes include first-attempt insertion failure, oxygen saturation, ventilation parameters, mucosal trauma, pulmonary aspiration, and Apgar scores. Differences between labor status were tested using Student's t-test, Mann-Whitney U test, or Fisher's exact test, as appropriate. Quantitative associations between labor status and outcomes were determined using univariate logistic regression analysis.

RESULTS

Data from 584 parturients were analyzed, with 37.8% in labor. Labor did not significantly affect time to effective ventilation (mean (SD) for labor: 16.0 (5.75) seconds; no labor: 15.3 (3.35); mean difference: -0.65 (95%CI: - 1.49 to 0.18); p = 0.1262). However, labor was associated with increased first-attempt insertion failure and blood on sLMA surface. No reduction in oxygen saturation or pulmonary aspiration was noted.

CONCLUSIONS

Although no significant increase in time to effective ventilation was noted, labor may increase the number of insertion attempts and oropharyngeal trauma with sLMA use for cesarean delivery in parturients at low risk of difficult airway. Future studies should investigate the effects of labor on LMA use in high risk parturients.

TRIAL REGISTRATION

The study was prospectively registered at clinicaltrials.gov ( NCT02026882 ) on 3 January 2014.

Comparison of the standard and triple airway maneuvering techniques for i-gel™ placement in patients undergoing elective surgery: a randomized controlled study

PURPOSE

The i-gel is a supraglottic airway device with non-inflatable cuff which can suffer insertion failure if its standard placement technique is implemented. The aim of this study was to compare the placement technique proposed by the manufacturer of i-gel with the triple airway maneuver in terms of successful device insertion time and first-attempt success.

METHODS

After ethics committee approval, 103 ASA I-III patients were randomly allocated to the standard or triple airway maneuver groups. In the standard Group, the i-gel was inserted in the sniffing position while, in the triple group, it was inserted using the triple airway maneuver consisting of head tilt, jaw thrust, and open mouth. The time taken for successful insertion, first-attempt success rate, i-gel position, airway complications, and hemodynamic responses were assessed.

RESULTS

Between the two groups patient characteristics were similar. Time for successful insertion was significantly shorter in the triple group (20 ± 7 s) than with the standard technique (32 ± 11 s; p < 0.001). Successful insertion at the first attempt was 78% and 92% for the standard and triple group, respectively (p = 0.092). The i-gel position, airway complications, and hemodynamic responses were similar in both groups.

CONCLUSION

The triple airway maneuver required less i-gel insertion time as compared with the standard placement technique. First-attempt success rates were similar with both techniques, although the triple airway maneuver was superior to the standard method as a rescue technique in failed insertions. We therefore recommend use of the triple airway maneuver in i-gel insertion.