Object. The nitric oxide system has been linked to the pathogenesis of aneurysmal subarachnoid hemorrhage (SAH). The authors performed a case-control study to investigate the association between SAH and common genetic variants within the endothelial nitric oxide synthase gene (NOS3).Methods. Three hundred thirty-three Caucasian SAH patients and 498 controls were genotyped for the -922A > G (rs 1800779), -786T > C (rs2070744), and 894G > T (rs1799983) single nucleotide polymorphisms and the intron-4 27-bp variable number of tandem repeats polymorphism (27-bp-VNTR).Results. The b/b (5 repeats) genotype of the 27-bp-VNTR was overrepresented in cases (77%) versus controls (69%) (p = 0.02). In male patients the b/b genotype was found in 85% compared with 67% in male controls, whereas in women, the frequencies were 73% and 72%, respectively. This corresponds to an odds ratio of 2.8 (95% CI 1.5-5.6, p = 0.0005) for SAH in men with the b/b genotype versus men with a/b or a/a. In women, no such association was found (OR 1.1, 95% CI 0.7-1.6, p = 0.76). Stepwise logistic regression including arterial hypertension, smoking, sex, and age with interactions yielded similar effect estimates of the 27-bp-VNTR. Haplotype analysis revealed that no single haplotype containing the b-allele was responsible for the observed genotype effect.Conclusions. The authors' results suggest that the NOS3 27-bp-VNTR b/b genotype independent of other risk factors act in concert with male sex to substantially increase risk of SAH. This effect is not mediated by any single NOS3 haplotype.

Background Failure in airway management continues to cause preventable patient harm, and the recommended continuing education is challenged by anesthesiologists’ unknown knowledge gaps. This study aimed to identify anesthesiologists’ subjective and objective knowledge gaps as well as areas where anesthesiologists are incorrect and unaware. Methods An adaptive E‐learning program with 103 questions on adult airway management was used for subjective and objective assessment of anesthesiologists’ knowledge. All anesthesiologists in the Capital Region of Denmark were invited to participate. Results The response rate was 67% (191/285). For preoperative planning, participants stated low confidence (subjective assessment) regarding predictors of difficult airway management in particular (69.1%‐79.1%). Test scores (objective assessment) were lowest for obstructive sleep apnea as a predictor of difficult airway management (28.8% correct), with participants being incorrect and unaware in 33.5% of the answers. For optimization of basic techniques, the lowest confidence ratings related to patient positioning and prediction of difficulties (57.4%‐83.2%), which agreed with the lowest test scores. Concerning advanced techniques, videolaryngoscopy prompted the lowest confidence (72.4%‐85.9%), while emergency cricothyrotomy resulted in the lowest test scores (47.4%‐67.8%). Subjective and objective assessments correlated and lower confidence was associated with lower test scores: preoperative planning [r = −.58, P < .001], optimization of basic techniques [r = −.58, P = .002], and advanced techniques [r = −.71, P < .001]. Conclusion We identified knowledge gaps in important areas of adult airway management with differing findings from the subjective and objective assessments. This underlines the importance of objective assessment to guide continuing education.