The association of body mass index with difficult tracheal intubation management by direct laryngoscopy: a meta-analysis

Abstract

BackgroundObesity is a serious disorder and may bring about many difficulties of perioperative management. A systematic review was conducted to assess the association between obesity and difficult intubation.MethodsWe searched electronic databases for related reviews and references of meta-analyses on August 14, 2017. The databases of PubMed, Embase, and the Cochrane controlled trials register were searched compared obese with non-obese patients in which difficult intubation rate of the adult population were retrieved. Patients with a BMI ≥ 30 kg·m− 2 were considered obese. The primary outcome was difficult tracheal intubation; secondary outcomes were the rates of difficult laryngoscopy and Mallampati score ≥ 3. This review included papers published from 1998 to 2015.ResultsThis review included 204,303 participants in 16 studies. There was a statistically significant association between obesity and risk of difficult tracheal intubation (pooled RR = 2.04, 95% CI: 1.16–3.59, p = 0.01; I2 = 71%, p = 0.008, Power = 1.0). It also showed significantly association between obesity and risk of difficult laryngoscopy (pooled RR = 1.54, 95% CI: 1.25–1.89, p < 0.0001; I2 = 45%, p = 0.07, Power = 1.0), obesity and risk of Mallampati score ≥ 3 (pooled RR = 1.83, 95% CI: 1.24–2.69, p = 0.002; I2 = 81%, p < 0.00001, Power = 0.93). However, there were no association of obesity and risks of difficult intubation compared with non-obesity in the cohort studies (pooled RR = 3.41, 95% CI: 0.88–13.23, p = 0.08; I2 = 50%, p = 0.14) and the elective tracheal intubation (pooled RR = 2.31, 95% CI: 0.76–6.99, p = 0.14; I2 = 73%, p = 0.01), no associated with an increased risk of difficult laryngoscopy in the sniffing position (pooled RR = 2.00, 95% CI: 0.97–4.15, p = 0.06; I2 = 67%, p = 0.03).ConclusionObesity was associated with an increased risk of difficult intubation, difficult laryngoscopy and Mallampati score ≥ 3 in adults patients undergoing general surgical procedures. However, there were no association of obesity and risks of difficult intubation compared with non-obesity in the cohort studies and the elective tracheal intubation, no associated with an increased risk of difficult laryngoscopy in the sniffing position. Future analyses should explore the association of BMI and difficult airway.

Preoperative X-ray C2C6AR is Applicable for Prediction of Difficult Laryngoscopy in Patients With Cervical Spondylosis

“…A signi cantly greater proportion of di cult laryngoscopy and tracheal intubation had been found in obese patients [11,12]. However, in our study, we found there was no signi cant difference between the easy and di cult groups (25.1±3.3 vs 25.7±2.5, P=0.261) which was in accordance with the study reported by Prakash et al [13].…”

No radiographic index predicts difficult intubation using the Optiscope™ in cervical spine surgery patients: a retrospective study

“…The narrow space between the posterior pharyngeal wall and tongue base can make intubation with the Opti-scope™ difficult by hindering its advancement into the hypopharynx. Obesity is known to predict difficult intubation with rigid fiberscopes and lightwands as well as direct laryngoscopes [11]. Although its retromolar or paraglossal aprroach is different from the Optiscope™, the Bonfils™ (Karl Storz Endoscopy, Tuttlingen, Germany), a rigid fiberscope, is similar to the Opti-scope™ in terms of its J-shaped structure and scooping movements.…”

“…In clinical practice, it is important for anesthesiologists to recognize the factors predicting difficult intubation before anesthetic induction. Numerous studies have shown that body mass index (BMI), Mallampati score, and mouth opening predict difficult intubation with intubation devices such as direct laryngoscopes, videolaryngoscopes, and lightwands [11][12][13][14]. Regarding radiographic indices associated with difficult intubation, tongue area, atlanto-occipital gap, mandibulohyoid distance, and the angle of the anterior-inferior point of the upper incisor with the neck in extension are related to difficult laryngoscopy, while epiglottis length is associated with increased intubation time when using lightwands [15][16][17][18].…”

Comparison of Laryngoscopic Views between C-MAC™ and Conventional Laryngoscopy in Patients with Multiple Preoperative Prognostic Criteria of Difficult Intubation. An Observational Cross-Sectional Study

“…Furthermore, BMI was also measured in all patients. A cut-off of BMI > 30 kg•m −2 was chosen as a risk factor for difficult intubation [16].…”