Smoking affects the hemodynamic changes induced by intubation Park [17] argued that the baseline blood pressure and heart rate are not different for smokers and nonsmokers. In fact, in a non-stimulated state, nicotine affects the sympathetic nervous system, it elevates the heart rate and it causes vasoconstriction. Smokers who abstained from smoking for a short period of time experience a reduction in the plasma catecholamine level, which reduces the heart rate and arterial blood pressure [18]. This current study showed no difference in the baseline heart rate or MAP between the smokers and nonsmokers. So our research findings were in accordance with the findings of Jee and Park [17]. But the difference in research findings among the different studies is construed to be due to the different characteristics of the patient subjects such as their age, their history of smoking and their history of abstinence from smoking. Smoking elevates the blood pressure and the heart rate, but abstinence from smoking during a period of preparation for surgery shows various hemodynamic responses depending on the duration of abstinence and the patients age and gender. Further research needs to be done on this. Moreover, there is no study on the effect of the smoking period on the cardiovascular system, so this needs further research as well. Smoking has a strong adrenergic agonistic effect, and so it increases the blood pressure, heart rate and systemic vascular resistance [19]. The change in heart rate is controlled by the autonomic nervous system. The effect the autonomic nervous system has on the sinus node is ever-changing due to internal and external factors. The regular change in the heart rate is called heart rate variability. Smoking is said to reduce such heart rate variability [20]. Such reductions are a serious risk factor for cardiac diseases [21,22]. Smokers are two times more as likely to suffer from coronary arterial diseases than are nonsmokers [23,24]. This study showed that there was a difference in the hemodynamic response to endotracheal intubation between male smokers and nonsmokers, while there was not such a difference in the female groups. Jee and Moon [25] reported that men have a longer sustained elevation of systolic blood pressure. It appears that the length of the blood pressure elevation is gender-based, so it is believed that gender also affects the change in hemodynamic responses. Hinojosa- Laborde et al. [26] reported that there is a gender difference in the control of the sympathetic nervous system. The control of the sympathetic nervous system in women is a bit more efficient than that in men. In this study, there was no difference in the endotracheal intubation-caused hemodynamic response in the women groups, regardless of whether they smoked or not. Perhaps this is because the efficient control of the sympathetic nervous system offsets the hemodynamic responses. In conclusion, for men, there was a difference in the hemo- 512 Vol. 58, No. 6, June 2010 dynamic response to endotracheal intubation using remifen- tanil between the smokers and nonsmokers. However, for women, there was no such difference. There has been much controversy over the gender difference of the endotracheal intubation-caused hemodynamic change. For obtaining consistent results, more research should be performed with controlling for many factors. References 1. Sikka PK. Basic pharmacologic principles. In: Basics of anesthesia. 5th ed. Edited by Stoelting RK, Miller RD: Philadelphia, Churchill Livinstone Elsevier. 2007, pp 41-2. 2. Shim MS, Kim JD, Choi HK, Yoo SB, Ryu SJ, Kim KH, et al. Optimal dose of remifentanil and propofol TCI for minimizing cardio- vascular changes to tracheal intubation during total intravenous anesthesia. 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