The Southern Medical Journal (SMJ) is the official, peer-reviewed journal of the Southern Medical Association. It has a multidisciplinary and inter-professional focus that covers a broad range of topics relevant to physicians and other healthcare specialists.

SMJ // Article

Original Article

Analysis of Airway Management for Cesarean Delivery: Use of Risk and Proportion Differences

Authors: Andrew King, MD, Justin Morello, MD, Allison Clark, MD, Adrienne Ray, MD, Colleen Martel, MD, Roneisha McLendon, MD, Anne McConville, MD, Melissa Russo, MD, Liane Germond, MD, Bobby Nossaman, MD

Abstract

Objectives: Securing the parturient airway is essential during general anesthesia for cesarean delivery. The purpose of this study was to compare inferior airway views provided by the use of three commonly available laryngoscopy blades—Macintosh, Miller, or Glidescope Mac-Style—to the incidence of difficult orotracheal intubation.

Methods: Following institutional review board approval, data from 449 electronic medical records in parturients undergoing general anesthesia for cesarean delivery were extracted during a 6-year period. The association of these blades with difficult orotracheal intubation was analyzed with risk and proportion differences measures of effect size.

Results: The overall incidence of difficult orotracheal intubation was 4.2% (95% confidence interval 2.7 − 6.5%), with 6 failed orotracheal intubations (5 laryngeal mask airways rescues and 1 mask rescue). Clinically important increases in risk differences for difficult orotracheal intubation were observed in parturients with restricted mouth openings, modified Mallampati III and IV views, and reduced thyromental distances. When modified Cormack-Lehane views were grouped into III and IV versus I and II cohorts; proportion differences for difficult orotracheal intubation were dependent upon the type of blade used, with the Miller blade providing the lowest proportion difference.

Conclusions: Miller blade laryngoscopy provided the lowest proportion difference for difficult orotracheal intubation during general anesthesia for cesarean delivery. Miller blade laryngoscopy provides effective procurement of the parturient airway.
Posted in: Obstetrics and Gynecology94 Pregnancy37

This content is limited to qualifying members.

Existing members, please login first

If you have an existing account please login now to access this article or view purchase options.

Purchase only this article ($25)

Create a free account, then purchase this article to download or access it online for 24 hours.

Purchase an SMJ online subscription ($75)

Create a free account, then purchase a subscription to get complete access to all articles for a full year.

Purchase a membership plan (fees vary)

Premium members can access all articles plus recieve many more benefits. View all membership plans and benefit packages.

References

1. Kinsella SM, Winton AL, Mushambi MC, et al. Failed tracheal intubation during obstetric general anaesthesia: a literature review. Int J Obstet Anesth 2015;24:356–374.
 
2. Practice guidelines for management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 1993;78:597–602.
 
3. Apfelbaum JL, Hagberg CA, Caplan RA, et al. Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 2013;118:251–270.
 
4. Practice Guidelines for Obstetric Anesthesia: an updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology 2016;124:270–300.
 
5. Hawkins JL. American Society of Anesthesiologists' Practice Guidelines for Obstetric Anesthesia: update 2006. Int J Obstet Anesth 2007;16:103–105.
 
6. Mayer DC, Spielman FJ. New practice guidelines for obstetric anesthesia. Obstet Gynecol Surv 2000;55:593–594.
 
7. Lewin SB, Cheek TG, Deutschman CS. Airway management in the obstetric patient. Crit Care Clin 2000;16:505–513.
 
8. Kuczkowski KM, Reisner LS, Benumof JL. Airway problems and new solutions for the obstetric patient. J Clin Anesth 2003;15:552–563.
 
9. Munnur U, de Boisblanc B, Suresh MS. Airway problems in pregnancy. Crit Care Med 2005;33:S259–268.
 
10. Mushambi MC, Kinsella SM, Popat M, et al. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics. Anaesthesia 2015;70:1286–1306.
 
11. Alanoglu Z, Erkoc SK, Guclu CY, et al. Challenges of obstetric anesthesia: difficult laryngeal visualization. Acta Clin Croat 2016;55(Suppl 1):68–72.
 
12. Scott-Brown S, Russell R. Video laryngoscopes and the obstetric airway. Int J Obstet Anesth 2015;24:137–146.
 
13. Balki M, Cooke ME, Dunington S, et al. Unanticipated difficult airway in obstetric patients: development of a new algorithm for formative assessment in high-fidelity simulation. Anesthesiology 2012;117:883–897.
 
14. Mushambi MC, Jaladi S. Airway management and training in obstetric anaesthesia. Curr Opin Anaesthesiol 2016;29:261–267.
 
15. Preston R. Management of the obstetric airway—time for a paradigm shift (or two)? Int J Obstet Anesth 2015;24:293–296.
 
16. Kim HY. Statistical notes for clinical researchers: effect size. Restor Dent Endod 2015;40:328–331.
 
17. Kim HY. Statistical notes for clinical researchers: risk difference, risk ratio, and odds ratio. Restor Dent Endod 2017;42:72–76.
 
18. Chow S-C, Shao J, Wang H, et al. Sample Size Calculation in Clinical Research, 3rd ed. Boca Raton, FL: CRC Press; 2007.
 
19. Forthofer RN, Lee ES, Hernandez M. Biostatistics: A Guide to Design, Analysis, and Discovery, 2nd ed. New York: Academic Press; 2007.
 
20. Machin D, Campbell MJ, Walters SJ. Medical Statistics: A Textbook for the Health Sciences, 4th ed. New York: John Wiley & Sons; 2007.
 
21. Rose DK, Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anaesth 1994;41:372–383.
 
22. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984;39:1105–1111.
 
23. Samsoon GL, Young JR. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987;42:487–490.
 
24. Rose DK, Cohen MM. The incidence of airway problems depends on the definition used. Can J Anaesth 1996;43:30–34.
 
25. Landry WB 3rd, Nossaman BD. Airway risk factors for the Miller laryngoscope blade. J Clin Anesth 2016;33:62–67.
 
26. Ural K, Subaiya C, Taylor C, et al. Analysis of orotracheal intubation techniques in the intensive care unit. Crit Care Resusc 2011;13:89–96.
 
27. McIntyre JW. Laryngoscope design and the difficult adult tracheal intubation. Can J Anaesth 1989;36:94–98.
 
28. Marks RR, Hancock R, Charters P. An analysis of laryngoscope blade shape and design: new criteria for laryngoscope evaluation. Can J Anaesth 1993; 40:262–270.
 
29. Butler PJ, Dhara SS. Prediction of difficult laryngoscopy: an assessment of the thyromental distance and Mallampati predictive tests. Anaesth Intensive Care 1992;20:139–142.
 
30. Krom AJ, Cohen Y, Miller JP, et al. Choice of anaesthesia for category-1 caesarean section in women with anticipated difficult tracheal intubation: the use of decision analysis. Anaesthesia 2017;72:156–171.
 
31. Girard T, Palanisamy A. The obstetric difficult airway: if we can't predict it, can we prevent it? Anaesthesia 2017;72:143–147.
 
32. Arino JJ, Velasco JM, Gasco C, et al. Straight blades improve visualization of the larynx while curved blades increase ease of intubation: a comparison of the Macintosh, Miller, McCoy, Belscope and Lee-Fiberview blades. Can J Anaesth 2003;50:501–506.
 
33. Sullivan GM, Feinn R. Using effect size—or why the P value is not enough. J Grad Med Educ 2012;4:279–282.
 
34. Katz MH. Study Design and Statistical Analysis: A Practical Guide for Clinicians. New York: Cambridge University Press; 2006.
 
35. Hulley SB, Cummings SR, Browner WS, et al. Designing Clinical Research, 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007.