Predicting difficult airways: 3-3-2 rule or 3-3 rule?

T Yu, B Wang, X J Jin, R R Wu, H Wu, J J He, W D Yao, Y H Li
Irish Journal of Medical Science 2015, 184 (3): 677-83

BACKGROUND: The goal of this study was to assess the value of the 3-3 rule and the 3-3-1 rule in predicting difficult airways.

METHODS: The authors conducted an observational study over a 6-month period. For each consenting adult patient undergoing general anesthesia, preoperative patient characteristics and data regarding difficult airway assessments and airway outcomes were collected. The 3-3-2 rule, 3-3-1 rule and 3-3 rule were included in preoperative difficult airway assessments. The 3-3-1 rule is defined as an interincisor distance (IID) less than three fingers, a hyoid-mental distance (HMD) less than three fingers, and a hyoid-thyroid cartilage distance (HTD) less than one finger.

RESULTS: Among the 732 patients who were successfully recruited in this study, 67 patients had difficult laryngoscopy (DL) (9.2 %), and 25 patients had difficult intubation (DI) (3.4 % of the total). All of the DI patients were also DL patients (25/67, 37.3 %). The AUC of the 3-3-2, 3-3, and 3-3-1 rules for predicting difficult laryngoscopy were 0.702, 0.709, and 0.631, respectively. Significant differences between the 3-3-2 and 3-3-1 rules as well as between the 3-3 and 3-3-1 rules were evident. The AUC values for the 3-3-2, 3-3, and 3-3-1 rules for predicting DI were 0.830, 0.822, and 0.725, respectively.

CONCLUSIONS: The 3-3 rule and the 3-3-2 rule are similar regarding their ability to predict difficult airways. A HTD less than two fingers or one finger is not predictive of DV or DI.


You need to log in or sign up for an account to be able to comment.

No comments yet, be the first to post one!

Related Papers

Available on the App Store

Available on the Play Store
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"