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Objective To analyze retrospectively the correlation between the difficult airway and thyromental height by three-dimensional reconstruction among the Chinese. Methods Eithty patients who had been scanned by helical CT in the head and neck were allocated into two groups according to Cormack-Lehane grading:paients with Ⅰ-Ⅱ grade were allocated into group 1, and paients with Ⅲgrade were allocated into group 2. Reconstructed images were obtained by AW4.4 workstation and the following parameters were recorded and analyzed:the length from the oral to the under jaw(a), the length from the under jaw to the skin of the neck (b), the vertical distance from the under jaw to the neck was equal to thyromental height(c), the vertical distance from the oral to the cervical vertebra(d), the angle with the under jaw as the vertices and with two lines (a and b) for edge (angle ofα). Results The c value in two groups had no significant difference:(3.97 ± 0.82) cm vs. (3.64 ± 0.62) cm, P>0.05. The d value in group 2 was significantly higher than that in group 1:(8.69 ± 0.48) cm vs. (8.25 ± 0.80) cm, P<0.05. The c/d value and c/a value in group 2 were significantly lower than those in group 1: 0.42 ± 0.07 vs. 0.48 ± 0.12, 0.80 ± 0.18 vs. 0.95 ± 0.25, P<0.05. Conclusions Thyromental height by three-dimensional reconstruction has no significant differences in evaluating the difficult airway among the Chinese. The ratio of the vertical distance from the under jaw to the neck and the vertical distance from the oral to the cervical vertebra, and the ratio of the vertical distance from the under jaw to the neck and the length from the oral to the under jaw shows negative correlation with difficult airway.
ABSTRACT
Objective To investigate the characteristics of sagittal anatomic structure of the upper airway in patients with ankylosing spondylitis using three-dimensional reconstruction based on computed tomography (CT).Methods Thirty-one male patients with ankylosing spondylitis,aged 20-60 yr (AS group),and 41 common patients (male) without difficult airways,aged 20-60 yr (control group),who underwent spiral CT scan of the head and neck using Helical CT from January 2007 to February 2011 in our hospital,were enrolled in the study.Reconstructed images of the upper airway were obtained using AW4.4 workstation and six distances (D1-D6) and four angles (α-δ) were recorded and analyzed:(1)D1,the arc distance between the upper central incisor and root of epiglottis; D2,the distance between the upper central incisor and root of epiglottis; D3 and D4,the lengths of maxilla and mandible ; D5,the distance between the root of epiglottis and midpoint of glottis; D6,the distance between the end of mandible and midpoint of glottis; (2) angle α,the angle of line D2 and D5; angle β,the angle of line D2 and the lower edge of the upper central incisor to the midpoint of glottis; angle γ,the angle of line D4 and D6; angle δ,the angle of the point of the lower edge of the upper central incisor to the trailing edge of the hard palate and then to the root of epiglottis.Results Compared with control group,no significant change was found in D1,D2,D3,D4 and D5 (P ＞ 0.05),and D6,angle α and angle δ were significantly increased,whereas angle β and angle γ were decreased in AS group (P ＜ 0.05).Conclusion The anatomic structure of the upper airway has the characteristics of specific changes and a laryngoscope blade with a large degree of curvature may be helpful for successful tracheal intubation in patients with ankylosing spondylitis.
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Objective To evaluate the effects of peritoneal jet ventilation on peritoneal oxygenation in pigs.Methods Twenty-four pigs of both sexes (12-16 weeks,35-45 kg) were randomly divided into 3 groups (n=8 each): sham operation group (group S) ; peritoneal regular frequency jet ventilation group (16 bpm)(group N) and peritoneal high-frequency jet ventilation group (150 bpm) (group H).Oral tracheal intubation was performed.The animals were mechanically ventilated (VT 8-12 ml/kg,RR 12-16 bpm,I:E 1.0:1.5,FiO2 100％) via airway.Endotracheal tubes were inserted into abdomen through the incisions in the left lower (for peritoneal jet ventilation) and right upper quadrant (for outlet of air).Arterial blood PaO2 and PaCO2 were measured before (baseline) and at 30,60,90,120,150,180,210 and 240 s of peritoneal jet ventilation.Peritoneal jet ventilation was started after the lungs being mechanically ventilated for 35 min.Peritoneal jet ventilation was terminated when SpO2 dropped to SpO2 ＜ 90 ％.The duration of safe apnea (DSA,from the moment of begging of peritoneal jet ventilation to the time when PaO2 ＜ 60 mm Hg).Results PaO2 was significandy higher and DSA longer in group H than in groups S and N.But there was no significant difference in PaCO2 among the 3 groups.Conclusion Peritoneal high-frequency jet ventilation can significantly enhance the efficiency of peritoneal oxygenation and prolong DSA,while peritoneal regular frequency jet ventilation has no effect on peritoneal oxygenation.
