Age affects vascular morphology and predictiveness of anatomical landmarks for aortic zones in trauma patients: implications for resuscitative endovascular balloon occlusion of the aorta.

PURPOSE: Understanding the vascular morphology is fundamental for resuscitative endovascular balloon occlusion of the aorta. This study aimed to evaluate the effect of aging on length and diameter of aorta and iliac arteries in trauma patients, and to investigate the predictiveness of anatomical landmarks for aortic zones. METHODS: A total of 235 patients in a regional trauma center registry from September 1, 2018, to January 3, 2024, participated in the study. Reconstruction of computed tomography was applied to the torso area. The marginal diameter and length of aorta and iliac arteries were measured. Anatomical landmark distances and aortic marginal lengths were compared. RESULTS: The length and diameter of aorta and iliac arteries increased with age, and a tortuous and enlarged morphology was observed in older patients. There was a good regression between age and diameter of the aorta. Neither the jugular notch, the xiphisternal joint, nor the umbilicus could reliably represent specific margins of aortic zones. The distance between the mid-sternum and femoral artery (427 ± 25 to 442 ± 25 mm for right, and 425 ± 28 to 440 ± 26 mm for left) was predictive for zone 1 in all groups. The distance between the lower one-third junction of the xiphisternum to the umbilicus and femoral artery (232 ± 19 to 240 ± 17 mm for right, and 229 ± 20 to 237 ± 19 mm for left) was predictive for zone 3 aorta. CONCLUSION: Aging increases the length and diameter of aorta and iliac arteries, with a tortuous and enlarged morphology in geriatric populations. The mid-sternum and the lower one-third junction of the xiphisternum to the umbilicus were predictive landmarks for zone 1 and zone 3, respectively.

Effect of tiotropium on neural respiratory drive during exercise in severe COPD.

BACKGROUND: Studies have shown that tiotropium once daily reduces lung hyperinflation and dyspnea during exercise and improves exercise tolerance in patients with COPD. Mechanisms underlying the effects of the muscarinic receptor antagonist tiotropium on COPD have not been fully understood. OBJECTIVE: In this study, we investigated whether improvement in neural respiratory drive is responsible for reducing dyspnea during exercise and improving exercise tolerance in COPD. METHODS: Twenty subjects with severe COPD were randomized into two groups: no treatment (Control, n = 10, 63.6 ± 4.6 years, FEV1 29.6 ± 13.3%pred) or inhaled tiotropium 18 µg once daily for 1 month (n = 10, 66.5 ± 5.4 years, FEV1 33.0 ± 11.1%pred). All subjects were allowed to continue their daily medications other than anti-cholinergics during the study. Constant cycle exercise with 75% of maximal workload and spirometry were performed before and 1 month after treatment. Diaphragmatic EMG (EMGdi) and respiratory pressures were recorded with multifunctional esophageal catheter. Efficiency of neural respiratory drive, defined as the ratio of minute ventilation (VE) and diaphragmatic EMG (VE/EMGdi%max), was calculated. Modified British Medical Research Council Dyspnea Scale (mMRC) was used for the evaluation of dyspnea before and after treatment. RESULTS: There was no significant difference in spirometry before and after treatment in both groups. Diaphragmatic EMG decreased significantly at rest (28.1 ± 10.9% vs. 22.6 ± 10.7%, P < 0.05) and mean efficiency of neural respiratory drive at the later stage of exercise increased (39.8 ± 2.9 vs. 45.2 ± 3.9, P < 0.01) after 1-month treatment with tiotropium. There were no remarkable changes in resting EMGdi and mean efficiency of neural respiratory drive post-treatment in control group. The score of mMRC decreased significantly (2.5 ± 0.5 vs. 1.9 ± 0.7, P < 0.05) after 1-month treatment with tiotropium, but without significantly difference in control group. CONCLUSION: Tiotropium significantly reduces neural respiratory drive at rest and improves the efficiency of neural respiratory drive during exercise, which might account for the improvement in exercise tolerance in COPD.

[Neural respiratory drive in patients with obstructive sleep apnea].

OBJECTIVE: To evaluate the variability of neural respiratory drive in patients with obstructive sleep apnea (OSA) and the effect of continuous positive airway pressure (CPAP) upon neural respiratory drive. METHODS: We recorded diaphragm electromyogram (EMGdi) with multi-pair esophageal electrodes and its variability during wakefulness, sleep and treatment with CPAP in 13 patients with moderate to severe OSA diagnosed by an overnight full polysomnography (OSA group). Six normal subjects (control group) were also studied. RESULTS: Coefficient of variation of EMGdi (CV-EMGdi) during wakefulness (15.4% +/- 3.8%) was similar to that during sleep (17.3% +/- 5.2, P > 0.05) in the control group. The CV-EMGdi during wakefulness, sleep, sleep apnea events and treatment with CPAP in OSA group was 14.7% +/- 1.9%, 40.7% +/- 12.0%, 29.1% +/- 7.5% and 15.4% +/- 4.6% respectively, CV-EMGdi during sleep or sleep apnea events was larger than that during wakefulness (P < 0.01). However, there was no difference in the CV-EMGdi during wakefulness and during treatment with CPAP (P > 0.05). CONCLUSION: The variability of neural respiratory drive in patients with OSA is higher than that in normal subjects, and CPAP can reduce the variability of neural respiratory drive in patients with OSA.