Objective: In military aviation, high performance aircraft pilots are exposed to +Gz acceleration at longer durations and higher magnitude than transport/helicopter pilots. The purpose of this study was to reveal the negative or positive cardiac responses to this occupational high +Gz exposure. Methods: Our study design was cross-sectional and observational. We have evaluated 21 echocardiographic parameters of 63 pilots who applied for aircrew periodic medical examination. Of 63 pilots, 33 were grouped as high performance aircraft pilots group (Group A) and 30 were grouped as control group (Group B) whose aircraft type was transport or helicopter. Means of demographic and echocardiography parameters between two groups were compared statistically with Student's t-test, Mann-Whitney U or Chi-square test as appropriate. Results: Among all echocardiographic parameters, mean TV A (tricuspid valve peak velocity during late diastolic filling) was significantly higher and TV E (peak velocity during early diastolic filling)/ A ratio was significantly lower for Group A pilots (p<0.05). In Group A pilots, mean TV A and TV E/A ratio were (52.12±13.85) and (1.36±0.30) respectively. In Group B pilots, mean TV A and TV E/A ratio were (42.61±6.42) and (1.53±0.20) respectively (p=0.001 for TVA and p=0.005 for TV E/A). Mean pulmonary artery pressure (PAP) of Group A pilots (32.04±9.09) was higher than Group B pilots (28.76±7.9) but it was not statistically significant (p>0.05). Conclusion: We conclude that according to the results of our study, long term +Gz exposure has no effects on cardiac morphologic and systolic functions but has effects on right ventricular diastolic functions. We have considered that these effects may be a result of chronic +Gz adaptation or high PAP levels. (Anadolu Kardiyol Derg 2012; 12: 668-74)
Background: Smoking may impair oxygen transport ability of blood and airway destructions might be seen in long term smokers. After 1-3 cigarette smoking, it leads to a rise in carboxyhemoglobin level in blood, and it has a negative effect such as taking extra 5,000-8,000 feet altitude. Thus, it is thought that smoking before or in-flight may contribute to altitude hypoxia. The objective of this study was to evaluate the effects of smoking on acute hypobaric hypoxia tolerance at 30,000 ft. simulated altitude. Materials and Methods:This study was planned prospectively, and a standardized survey that consisted of smoking status and demographic characteristics of subjects was applied before the procedures. Aircrews are exposed to high altitude during "Hypobaric Hypoxia Training" in an altitude chamber. Pulse oximeter measurements were done to analyze oxygen saturations during different stages of the hypoxia trainings.Results: Seventy eight male healthy aircrews were included in this study. Twenty five (32.1%) of subjects stated that they were currently smoking (4.9±2.6 years). Hypoxic pulse oximeter mean values of the Nonsmoker Group were higher than those of the Smoker Group (p>0.05). The three most frequently checked symptoms were numbness, tingling and perspiration among all participants. Flushing was the most frequent symptom in the Smoker Group while numbness was the most frequent symptom in the Nonsmoker Group. Both early and late symptoms among pilots were higher in the Smoker Group (p>0.05). More symptoms were checked among smokers during hypoxia exposure in this study(p>0.05). Conclusion:Our results might be attributed to hypoxia sensitiveness of smokers, and the use of tobacco products by aviation personnel was considered to be disadvantage in aviation environment. Because of this, doctors who carry out aviation examinations and practise preventive medicine in aviation field should be aware of the importance of this issue. The influences of carboxyhemoglobin on hypoxia tolerance might be better observed at lower altitudes if this study would have been redone at 18,000 and 25,000 simulated altitudes.
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