Can difficult intubation be easily and rapidly predicted?

AIM: Failed endotracheal intubation and inadequate ventilation with subsequent insufficient oxygenation can result in serious complications potentially leading to permanent health damage. Difficult intubation may occur not only in patients with apparent pathologies in the orofacial region but also, unexpectedly, in those without abnormalities. This study aimed at finding anthropometric parameters that are easy to examine and that would aid in predicting difficult intubation. METHOD: A case-control study was undertaken. Based on defined criteria, 15 parameters were examined in patients with unanticipated difficult intubation. The parameters included a previous history of difficult intubation, pathologies associated with difficult intubation, clinical symptoms of airway pathology, the Mallampati score, upper lip bite test, receding mandible, and cervical spine and temporomandibular joint movement. Thyromental, hyomental and sternomental distances and inter-incisor gap were measured. The methods were precisely defined and the measurements were carried out by a trained anesthesiologist. Statistical analysis was performed on data from 74 patients with difficult intubation and 74 control patients with easy intubation. RESULTS: Significant predictors of difficult intubation were inter-incisor gap (IIG), thyromental distance (TMD) and class 3 limited movement of the temporomandibular joint. The IIG and TMD cut-offs were set at 42 mm and 93 mm, respectively. CONCLUSION: The results will be used to confirm these predictors in an anesthesiology clinic along with the aid of the laryngoscopic findings to improve the prediction of unanticipated difficult intubation.

Inter-observer reproducibility of 15 tests used for predicting difficult intubation.

AIM: To determine the inter-observer reproducibility of 15 tests used for predicting difficult tracheal intubation (DI). MATERIAL AND METHODS: Following local ethics committee approval and informed consent, 101 volunteers were examined by two assessors using 15 tests for predicting DI. The two assessors who were blinded to the results of the other, examined each volunteer independently. Cohen's kappa (κ) or first-order agreement coefficient (AC1) were used to measure agreement between assessor ratings on a qualitative scale. Agreement between two quantitative outcomes was described using the intraclass correlation coefficient (ICC) and Pearson's (PCC) or Spearman's (SCC) correlation coefficients. The following interpretation of the coefficients was used: poor (< 0.20), fair (0.21-0.40), satisfactory (0.41-0.60), good (0.61-0.80), and excellent (0.81-1.00). RESULTS: Respective coefficients of inter-rater agreement and correlation coefficients were determined for the following parameters: pathologies associated with DI (κ=0.662, AC1=0.990), clinical impression (κ=-0.013, AC1=0.969), modified Mallampati test (κ=0.503, AC1=0.861), upper lip bite test (κ=0.370, AC1=0.897), temporo-mandibular joint movement (κ=0.088, AC1=0.797), max. anteroflexion of C-spine (ICC=0.136, SCC=0.391), max. retroflexion of C-spine (ICC=0.020, SCC=0.284), mandibular length (ICC=0.301, SCC=0.553), neck circumference (ICC=0.832, SCC=0.928), hyo-mental distance (ICC=0.378, SCC=0.472), thyro-mental distance (ICC=-0.002, PCC=0.265), sternomental distance (ICC=0.674, PCC=0.815), and finally, inter-incisor gap (ICC=0.695, PCC=0.785). Two tests (positive history of DI and retrogenia), were excluded from calculation because no positive cases were found. CONCLUSION: Best inter-rater agreement was found for the assessment of neck circumference while the highest discrepancies between raters were in goniometrically-measured mobility of the C-spine. Many of the pre-operative airway tests had only fair inter-observer reproducibility. This may be one reason why models for predicting difficult intubation are not universally reliable.

Renal cancer risk and occupational exposure to polycyclic aromatic hydrocarbons and plastics.

OBJECTIVE: To investigate whether occupational exposure to polycyclic aromatic hydrocarbons and certain plastic monomers increased renal cell carcinoma (RCC) risk. METHODS: Unconditional logistic regression was used to calculate RCC risk in relation to exposure. RESULTS: No association between RCC risk and having ever been occupationally exposed to any polycyclic aromatic hydrocarbons or plastics was observed. Duration of exposure and average exposure also showed no association with risk. Suggestive positive associations between RCC risk and cumulative exposure to styrene (P-trend = 0.02) and acrylonitrile (P-trend = 0.06) were found. Cumulative exposure to petroleum/gasoline engine emissions was inversely associated with risk (P-trend = 0.02). CONCLUSIONS: Results indicate a possible association between occupational styrene and acrylonitrile exposure and RCC risk. Additional studies are needed to replicate findings, as this is the first time these associations have been reported and they may be due to chance.

Occupation and risk of lung cancer in Central and Eastern Europe: the IARC multi-center case-control study.

OBJECTIVE: We sought to evaluate the role of occupation and industry in lung carcinogenesis in six countries in Central and Eastern Europe. METHODS: This multi-center case-control study included 2,056 male and 576 female lung cancer incidence cases diagnosed from 1998 to 2001 and 2,144 male and 727 female controls frequency-matched for sex and age. Unconditional regression models were applied to calculate the odds ratios after controlling for potential confounders including age (5-year groups), study center (15 centers), and tobacco pack-years. RESULTS: Elevated odds ratios (ORs) were found for men employed as production workers (OR 1.45, 95% CI 1.22-1.72), bookkeepers and cashiers (1.81, 1.03-3.24), general farmers (1.67, 1.08-2.60), livestock workers (2.54, 1.09-5.88), miners (2.17, 1.47-3.23), toolmakers and metal patternmakers (2.56, 1.34-4.94), glass formers (2.55, 1.18-5.50), dockworkers, and freight handlers (1.49, 1.04-2.12). Industries with elevated risk among men included mining (1.75, 1.20-2.57), manufacture of cement, lime, or plaster (3.62, 1.11-12.00), casting of metals (2.00, 1.17-3.45), manufacture of electric motors (2.18, 1.24-3.86). For women, elevated ORs were found for medical, dental, veterinary doctors (2.54, 1.01-6.31), librarians and curators (7.03, 1.80-27.80), sewers 3.63 (1.12-10.23). CONCLUSIONS: This study identifies new areas for further, explanatory analyses, especially in production work, and indicates new possible sources of exposure to cancer risk for women.