Airway changes during labor and delivery.
BACKGROUND
There are no prospective studies that evaluated airway changes during labor. The purpose of this study was to evaluate airway changes in women undergoing labor and delivery.


METHODS
Two studies were undertaken to evaluate airway changes during labor. The first study used the conventional Samsoon modification of the Mallampati airway class. The airway was photographed at the onset and the end of labor. Women with class 4 airways were excluded from initial participation. In the second study, upper airway volumes were measured using acoustic reflectometry at the onset and the conclusion of labor. Acoustic reflectometry software computed the values for the components of upper airway, oral volume, and pharyngeal volume.


RESULTS
In study 1 (n = 61), there was a significant increase in airway class from prelabor to postlabor (P < 0.001). The airway increased one grade higher in 20 (33%) and two grades higher in 3 (5%) after labor. At the end of labor, there were 8 parturients with airway class 4 (P < 0.01) and 30 parturients with airway class 3 or class 4 (P < 0.001). In study 2 (n = 21), there were significant decreases in oral volume (n = 21; P < 0.05), and pharyngeal area (P < 0.05) and volume (P < 0.001) after labor and delivery. No correlation was observed between airway changes during labor and duration of labor, or fluids administered during labor in either study.


CONCLUSIONS
Airways can change during labor. Therefore, a careful airway evaluation is essential just before administering anesthesia during labor rather than obtaining this information from prelabor data.
Kodali
Bhavani-Shankar
BS
Department of Anesthesiology and Perioperative Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. bkodali@partners.org
Chandrasekhar
Sobhana
S
Bulich
Linda N
LN
Topulos
George P
GP
Datta
Sanjay
S
D000328:Adult; D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D007746:Labor Presentation; D007743:Labor, Obstetric / Q000502:physiology; D011247:Pregnancy; D012137:Respiratory System / Q000033:anatomy & histology*