Intubation In Women Research Articles

Frequency and Risk Factors for Difficult Intubation in Women Undergoing General Anesthesia for Cesarean Delivery: A Multicenter Retrospective Cohort Analysis

(Anesthesiology. 2022;136:697–708) Elucidating the contemporary rate of difficult or failed intubation in women undergoing general anesthesia for cesarean delivery is confounded in the literature by small sample size, and the unaccounted-for increased use of neuraxial anesthesia and video laryngoscope, all amounting to generally outdated information available for this question. As the mother and neonate are at high risk for adverse outcome with difficult intubation, it is important to understand characteristics that may increase the likelihood of this complication, as to initiate pertinent preparation and early neuraxial anesthesia. The aim of this study was to determine an updated frequency of difficult and failed intubation in the obstetric setting and identify risk factors of such that may be particular to women receiving general anesthesia for cesarean delivery.

This Month in Anesthesiology

This Month in Anesthesiology

Frequency and Risk Factors for Difficult Intubation in Women Undergoing General Anesthesia for Cesarean Delivery: A Multicenter Retrospective Cohort Analysis.

Estimates for the incidence of difficult intubation in the obstetric population vary widely, although previous studies reporting rates of difficult intubation in obstetrics are older and limited by smaller samples. The goals of this study were to provide a contemporary estimate of the frequency of difficult and failed intubation in women undergoing general anesthesia for cesarean delivery and to elucidate risk factors for difficult intubation in women undergoing general anesthesia for cesarean delivery. This is a multicenter, retrospective cohort study utilizing the Multicenter Perioperative Outcomes Group database. The study population included women aged 15 to 44 yr undergoing general anesthesia for cesarean delivery between 2004 and 2019 at 1 of 45 medical centers. Coprimary outcomes included the frequencies of difficult and failed intubation. Difficult intubation was defined as Cormack-Lehane view of 3 or greater, three or more intubation attempts, rescue fiberoptic intubation, rescue supraglottic airway, or surgical airway. Failed intubation was defined as any attempt at intubation without successful endotracheal tube placement. The rates of difficult and failed intubation were assessed. Several patient demographic, anatomical, and obstetric factors were evaluated for potential associations with difficult intubation. This study identified 14,748 cases of cesarean delivery performed under general anesthesia. There were 295 cases of difficult intubation, with a frequency of 1:49 (95% CI, 1:55 to 1:44; n = 14,531). There were 18 cases of failed intubation, with a frequency of 1:808 (95% CI, 1:1,276 to 1:511; n = 14,537). Factors with the highest point estimates for the odds of difficult intubation included increased body mass index, Mallampati score III or IV, small hyoid-to-mentum distance, limited jaw protrusion, limited mouth opening, and cervical spine limitations. In this large, multicenter, contemporary study of more than 14,000 general anesthetics for cesarean delivery, an overall risk of difficult intubation of 1:49 and a risk of failed intubation of 1:808 were observed. Most risk factors for difficult intubation were nonobstetric in nature. These data demonstrate that difficult intubation in obstetrics remains an ongoing concern.

Valeur comparée des signes cliniques d'intubation difficile chez la femme

A prospective study was designed to compare the value of clinical signs aimed to predict difficult intubation in women. A group of 663 women, scheduled for elective surgery, were assessed by an anaesthetist at the preanaesthetic visit. Following parameters were assessed : the degree of mouth opening, the chin-hyoid bone and the chin-thyroid cartilage distances, dental and facial abnormalities, age, weight. All patients were ranked on the Mallampati scale. Another anaesthetist carried out the anaesthetic induction and endotracheal intubation. The latter was deemed to have been difficult if special procedures had been required (use of a stylet, a fibroscope, or Sellick's manœuvre). In accordance with these criteria 12.5 % of women were difficult to intubate. Furthermore, he assessed the degree of glottic exposure, using a Macintosh blade and according to Cormack's classification. Six per cent of women were ranked C or D in Cormack's classification (C : the glottic aperture was not seen ; D : the epiglottis was not seen). Finally 66 % of women with difficult intubation and 84 % of those with severely abnormal glottic exposure were ranked > 1 on the Mallampati scale. This scale had high sensitivity (0.84), but a specificity of only 0.66. Other clinical criteria (mouth opening, the chin-hyoid bone distance) had a lower sensitivities, but seemed more specific. Multivariate analysis showed that specificity could be improved (0.84) if the distance between the upper and lower incisor teeth (mouth opening) was associated with Mallampati's rank, without any loss in sensitivity. A simple chart is proposed to assess the risk of difficult intubation.