청정상수원확보를 위한 평림댐 수몰지내 지장물 철거 및 폐기물 처리

한영성,윤석화,Han, Yeong-Seong,Yun, Seok-Hwa 한국수자원학회 2007 물과 미래(한국수자원학회지) Vol.40 No.1

한강 하류권 급수체계 구축 1차사업 제7공구 도수시설공사 하천횡단 추진공법 (Head Jacking Shield)

김봉수,김윤구,윤석화,정원일,양영섭,이성원,Kim, Bong-Su,Kim, Yun-Gu,Yun, Seok-Hwa,Jeong, Won-Il,Yang, Yeong-Seop,Lee, Seong-Won 한국터널지하공간학회 2011 자연, 터널 그리고 지하공간 Vol.13 No.5

리더의 영향력 전술이 구성원의 직무수행에 미치는 영향

이수진(Lee Soo Jin),윤석화(Yun Seok Hwa),변국도(Byun Guk Do) 한국인적자원관리학회 2016 인적자원관리연구 Vol.23 No.3

빠르고 복잡한 경영 환경의 변화로 인해 조직 구성원들은 매번 예측할 수 없는 상황에 놓이게 되고, 이에 따라 조직의 리더에 대한 기대는 더욱 높아진다. 이러한 환경 하에서 전통적으로 타당하다고 인정되는 단일의 리더십을 복잡한 경영 현실에 적용하기에는 한계가 따를 뿐만 아니라, 실무적으로 그 효과 또한 제한적일 것이다. 이에 따라 구성원들에게 리더의 영향력을 효과적으로 발휘하기 위한 구체적인 행동 지침이 그 어느 때보다 필요하고 중요하다. 이에 본 연구에서는 리더의 영향력 전술이 구성원의 직무수행에 미치는 영향을 구체적으로 살펴보고자 한다. 대부분의 선행연구에서는 전술 자체의 선호와 선택에 초점이 맞추어져 영향력 전술의 효과에 대한 실증이 부족하였다. 또한 개념적 범주화를 한 선행연구에서의 일관되지 않은 연구 결과는 통일된 연구 축적을 어렵게 하는 결정적인 한계점이 될 것이다. 이에 따라 영향력 전술의 메타구분, 구체적으로 강성적(hard)·연성적(soft) 전술을 통해서 구성원의 직무수행에 미치는 효과를 검증하는 것은 영향력 전술의 이론적 공백을 메우며 실무적으로 유익한 지침을 제공할 수 있을 것이다. 나아가 영향력 전술과 결과 변수 간의 역동적인 관계를 파악하기 위해서는 둘 사이에 내재하는 메커니즘과 상황적 요인에 대한 이해가 필요하다. 과연 리더의 영향력 전술이 어떤 맥락에서 어떤 메커니즘을 거쳐 구성원의 직무수행에 영향을 미치게 되는가를 검토하기 위해 전술과 직무수행 사이의 매개변수와 조절변수에 대하여 실증하고자 한다. 이에 본 연구에서는 Breckler (1984)가 제시한 태도의 3요소인 행동·정서·인지적 측면 중 행동과 정서적 측면에 기반하여 구성원의 내재적 동기부여와 리더에 대한 호감의 매개효과를 검토하고, 구체적 상황 요인으로서 직무 특성인 역할모호성의 조절효과를 살펴볼 것이다. 이 과정은 리더의 영향력 전술과 구성원의 성과 간의 관계를 보다 체계적이고 명확하게 이해할 수 있게 하며 나아가 실무적 적용 가능성을 높일 수 있는 중요한 작업이 될 것이다. 본 연구는 국내 대기업 6개 조직에 근무하는 구성원들과 그들의 직속리더로 구성되었으며, 최종 리더-구성원 241쌍의 자료가 분석에 사용되었다. 위계적 회귀분석을 이용한 분석결과, 강성적 영향력 전술의 경우 구성원의 과업성과에 유의한 부적관계가, 연성적 영향력 전술의 경우 모든 직무수행에서 유의한 정적관계가 있는 것으로 나타났다. 또한 매개변수인 리더에 대한 호감이 연성적 영향력 전술과 모든 직무수행 간의 관계를 매개한다는 것을 알 수 있었다. 끝으로 조절효과의 경우, 강성적 영향력 전술과 과업성과와 조직지향 조직시민행동 사이의 관계에서 역할 모호성의 유의한 조절효과를 확인할 수 있었다. 본 연구의 시사점은 다음과 같다. 첫째, 메타 구분에 의한 리더의 각 영향력 전술이 구성원의 직무수행에 미치는 영향을 확인함으로써 조직상황에서 영향력 전술의 유효성을 실증적으로 밝혀냈다. 둘째, 각 영향력 전술과 구성원의 직무수행 간의 관계에 내재된 메커니즘의 일부를 규명함으로써 이론적으로 영향력 전술의 과정에 대한 이해를 높였을 뿐만 아니라 실무적으로도 전술 사용의 구체적인 효과를 제시함으로써 리더가 영향력 전술을 사용하는 것에 대한 설득력을 높이는데 기여하였다. 셋째, 영향력 전술과 역할 모호성 간의 상호작용효과를 일부 확인함으로써 영향력 전술의 효과를 실증함에 있어 구체적인 상황에 대한 이해를 도모하고자 하였다. 하지만 본 연구는 이러한 시사점에도 불구하고 몇 가지 한계점을 가지고 있다. 첫째, 횡단연구 설계로 인하여 인과관계를 명확히 하는데 한계가 있다. 둘째, 구성원의 다양한 직무활동에 대한 리더의 영향력 전술의 효과를 살펴볼 필요가 있다. 끝으로, 보다 다양한 측면에서 조절변수에 대한 검토가 이루어질 필요가 있다. 이상에서 언급한 본 연구의 한계점을 극복하고 향후 연구를 이어간다면 영향력 전술에 관한 이론의 전체적인 틀을 구성하는데 기여할 뿐만 아니라 구체적인 행동 지침을 요구하는 실무에서의 요청을 어느 정도 수용할 수 있을 것으로 기대된다. In today s severe competitive business environment, the role of leaders has become more and more important. One of the most significant determinants of leadership effectiveness is the success of influencing subordinates. To be effective as a leader in the organization, it is critical to influence his/her subordinates to meet desired organizational process and performance outcomes. The ways in which leaders affect their subordinates have been investigated in terms of influence tactics, which refers to the specific types of behaviors used to gain support for decisions, requests, and policies, and to motivate subordinates to implement them. Based on the work of Kipnis and colleagues (1980), many researchers have examined on identifying specific influence behaviors, categorizing the most frequently used tactics, and founding the antecedents of the use of influence tactics. However, much of existing research in this area has focused on assessing upward influence tactics, with less attention given to the influence tactics used by leaders to influence their subordinates. Accordingly, eminent scholars have urged researchers to examine the use and effectiveness of leaders influence tactics using established conceptual frameworks of dyadic influences as a foundation. Therefore, this study focuses on leaders downward influence tactics. Specifically, to advance the understanding of the dynamics of downward influence tactics in work settings, this study has three main purposes. First, this study investigates the relationship between leaders downward influence tactics and subordinates job performance (i.e., task performance and organizational citizenship behaviors: OCB) by grouping influence tactics into two meta-categories: hard tactics and soft tactics. Second, to examine a psychological process in this relationship, this study explores the mediating roles of intrinsic motivation and liking for the supervisor based on the three components of an attitude (i.e., cognitive, affective, and behavioral component). Third, recognizing the importance of situational factors in the leadership influence process, this study further investigates the moderating effects of subordinates role ambiguity in the relationships between leaders influence tactics and their job performance. Thus, our study takes an important step toward developing a better understanding of how influence tactics in general, and leaders downward influence tactics in particular, affect subordinates job performance. Data were collected from questionnaires distributed to subordinates and their direct supervisors in 6 major companies in South Korea. Most of the respondents were full-time focal employees in international electronic companies, international automobile companies, and nationwide telecom companies. After excluding missing data, we were able to match responses for a total of 241 pairs to constitute the final sample for this study. Hierarchical regression analysis was used to test all of the hypothesized relationships using SPSS 19.0. The results demonstrated not only the negative relationship between leaders hard influence tactics and subordinates task performance but also the positive relationships between leaders soft influence tactics and subordinates all job performance (i.e., task performance, OCBI, and OCBO). In addition, subordinates liking for their supervisors mediated the relationships between leaders soft influence tactics and subordinates job performance. The results of moderated multiple regression analyses suggested that role ambiguity moderated the relationships between leaders hard influence tactics and subordinates task performance and OCBO. Specifically, the negative relationships between leaders hard influence tactics and task performance/OCBO became stronger when role ambiguity was low than when it was high.

상사의 비인격적인 행동 유형과 구성원의 과업성과

박희태 ( Hee Tae Park ),손승연 ( Seung Yeon Son ),윤석화 ( Seok Hwa Yun ) 한국인적자원관리학회 2014 인적자원관리연구 Vol.21 No.3

본 연구는 상사의 부정적인 행동 중 최근 가장 주목 받고 있는 상사의 비인격적인 행동에 초점을 맞추었고, 상사의 비인격적인 행동이 구성원의 과업성과에 어떤 영향을 미치는지를 확인하였다. 기존 일부 연구에서는 상사의 비인격적인 행동이 구성원의 과업성과에 부정적인 영향을 미친다고 보고하였지만, 실제 현장에서는 과업성과에 긍정적인 영향을 미치는 사례도 발견된다. 따라서 본 연구는 상사의 비인격적인 행동과 과업성과 간의 관계가 일관되지 않은 이유를 살펴보고 그 관계를 실증하고자 하는 것이 주된 목적이다. 이를 위하여 상사의 비인격적인 행동을 하나의 요인 즉, 대인관련 요인으로만 간주한 기존 연구와는 달리 상사의 비인격적인 행동을 과업관련 행동과 대인관련 행동으로 구분하여 각각의 행동이 과업성과에 미치는 영향을 검증하였다. 분석을 위한 설문조사는 민간표본에서는 상사와 구성원 192쌍, 군표본에서는 상사와 구성원 175쌍으로부터 설문지를 회수하여 분석하였다. 분석결과 상사의 비인격적인 행동은 과업관련 행동과 대인관련 행동으로 구분되었으며, 상사의 비인격적인 행동의 직접효과는 대인관련 행동만 과업성과에 부적(-)인 관계가 유의하게 나타났다. 추가분석에서 과업관련 행동과 대인관련 행동의 상호작용효과를 분석한 결과 의미 있는 결과가 나타났다. 따라서 이에 대한 연구의 시사점과 한계점 및 향후 연구방향을 제시하였다. This study investigates the effect of abusive supervision; a topic of leadership holds an attention to the dark and destructive side of supervisory behavior, on subordinates’ task performance. Although several studies have shown that the negative aspects of abusive supervision, in practice, there is strong likelihood that abusive supervisory behavior can actually lead to positive outcomes of subordinates. Thus, the main objective of the present study is 1) unraveling the reason of inconsistent results of the prior studies contended with the effect of abusive supervision on its performance outcomes and 2) empirically examining the relationship between abusive supervision and subordinates’ task performance. In the present study, we propose that two facets of abusive supervision, which that are labeled as task-related abusive supervision and interpersonal-related abusive supervision, differently associated with subordinates’ task performance. Analyses of empirical data collected from 192 supervisor- subordinate dyads from several different Korean companies and 175 supervisor-subordinate dyads from different Korean military camps demonstrated that the construct of abusive supervision was segregated as two sub-dimensions (i.e. task-related abusive supervision, interpersonal-related abusive supervision). In addition, the result of hierarchical regression analysis supported the negative relationship between interpersonal-related abusive supervision and subordinates’ task performance, but not on the relation between task-related abusive supervision and subordinates’ task performance. Moreover, in the additional analysis, we found a significant interaction effect of task-related abusive supervision and interpersonal- related abusive supervision on the subordinates’ task performance. Theoretical and practical implications of the study and the suggestion for future research on the topic of abusive supervision will be discussed.

상사의 성격 특성과 차 상위 상사의 지원이 상사의 모욕적 행동에 미치는 영향에 관한 연구

이수진(Soo Jin Lee),박희태(Hee Tae Park),윤석화(Seok Hwa Yun),손승연(Seung Yeon Son) 한국경영학회 2009 經營學硏究 Vol.38 No.4

Lately, researchers have paid increasing attention to negative or destructive side of supervisory behavior, i.e. abusive supervision. Studies on abusive supervision mainly focused on the results of abusive supervision. However, there are not many studies that examined the antecedents of abusive supervision. Recognizing this issue, our study examined the antecedents of abusive supervision in order to enhance our understanding of abusive supervision. Especially, we examined the effects of supervisor’s personality traits and supervisor’s perception of support from his/her manager on abusive supervision. Applying social exchange theory and trait activation theory, we developed and empirically tested the following hypotheses: H 1: Supervisor’s conscientiousness is negatively related to abusive supervision. H 2: Supervisor’s agreeableness is negatively related to abusive supervision. H 3: Supervisor’s perception of support from his/her manager is negatively related to his/her own abusive supervision. H 4a: Supervisor’s perception of support from his/her manager moderates the negative relationship between supervisor’s conscientiousness and abusive supervision such that the relationship is stronger when support perception is low than when support perception is high. H 4b: Supervisor’s perception of support from his/her manager moderates the negative relationship between supervisor’s agreeableness and abusive supervision such that the relationship is stronger when support perception is low than when support perception is high. Survey packages were distributed to 178 pairs of platoon leaders and their immediate subordinate, deputy platoon leaders and 160 were returned. Among those, 111 dyadic data were used for analysis. Platoon leaders’ questionnaires included their own conscientiousness, agreeableness, and support perception (i.e., company commander’s support) while deputy platoon leaders measured platoon leaders’ abusive supervision. The results indicated that supervisor’s agreeableness and perception of support from his/ her direct manger were negatively related to abusive supervision, as expected. Also, we found that the relationship between supervisor’s agreeableness and abusive supervision was stronger when supervisor perception of support from his/her manger was low. However, there was no significant relationship between supervisor’s conscientiousness and abusive supervision and no significant interaction between supervisor’s conscientiousness and supervisor perception of support from his/her manger. In summary, Hypotheses 2, 3, and 4b were supported. This research has theoretical and practical implications. First, our results suggested that supervisor’s agreeableness and his/her support perception played a significant role in determining abusive supervision. In addition, our findings revealed that abusive supervision was influenced by the interaction of supervisor’s agreeableness and support perception. These findings implied that although supervisor’s low agreeableness leads to hostile act toward his/her subordinates, it produces abusive supervision only among supervisors who perceive support in low. In other words, managers played critical role reducing the abusive supervision. This research is not free from limitations. First, the cross-sectional research design precluded any inference of causality. Second, data were obtained from the Republic of Korea army so the extent of generalizability of our findings to other organizations and other culture contexts remains an empirical question. Third, there was no significant relationship between supervisor’s conscientiousness and abusive supervision. Future research should repeat our study using narrow measure of conscientiousness (e.g., duty & achievement striving) in order to more fully understand the relationship between conscientiousness and abusive supervision. Finally, our study examined the limited variables as antecedents. Future research should examine various variables, in

도움행동의 해석에 관한 연구

김보영(Bo Young Kim),박오수(Oh Soo Park),윤석화(Seok Hwa Yun) 한국경영학회 2010 經營學硏究 Vol.39 No.3

Recent firm- and job- related trends which translate into flatter organizational structure and more complex and collective tasks have enhanced coworker`s salience and their potential influence. In this change, coworker`s interpersonal helping behaviors are considered as important factor to influence on fellow employee`s attitudes and behaviors. In general, it has been argued that coworker`s interpersonal helping behaviors positively affect fellow employee`s attitudes and behaviors. However, recent literatures suggest that, consequences of interpersonal helping behaviors will be different according as how the intention of helping behaviors is interpreted by rater. Moreover, helping behaviors significantly affect task performance rating because these behaviors are frequently emphasized as like in-role behaviors in organization. Therefore, why coworker`s helping behaviors are subjectively interpreted has to be investigated before we discuss about consequences of coworker`s interpersonal helping behaviors. Specifically, characteristics of help giver (actor) and receiver (rater) have to be considered simultaneously for understanding rating process of interpersonal helping behaviors in dyadic coworker relationship. The purposes of this study are to explain the cognitive process involved in rating of interpersonal helping behaviors and to demonstrate the influence of actor`s and rater`s trait on rating process concerning helping behaviors. We investigated moderate effects of two variables; ability to modify self-presentation as an actor`s trait and self-enhancement motives as a rater`s trait on the relationship between coworker`s helping behaviors and coworker`s OCB-I rated by fellow employee. Hypotheses are like these. H 1: Help giver`s ability to modify self-presentation will moderate the relationship between actor`s help giving and the extent of actor`s OCB-I rated by help receiver. That is, the positive slope will become smaller in graph when ability to self-presentation is high than when ability to self-presentation is low. H 2: Help receiver`s self-enhancement motives will moderate the relationship between actor`s help giving and the extent of actor`s OCB-I rated by help receiver. That is, the positive slope will become smaller in graph when self-enhancement motives is high than when self-enhancement motives is low. We conducted empirical test for examining hypotheses. Data were collected using questionnaires from 150 dyads of an employee and his/her coworker. As the result of the hierarchical regression analyses for OCB-I, the moderate effects of ability to modify self-presentation and self-enhancement motives on the relationship between coworker`s help giving and coworker`s OCB-I perceived by employee were significant respectively (ability to modify self-presentation: β=-.17, p<.05, self-enhancement motives: β=-.14, p<.05). Therefore, these results provided supports for Hypothesis 1, and 2. Our study demonstrated that coworker`s interpersonal helping behaviors were easily rated as OCB- I by raters when help giver was high in ability to modify self-presentation. This result provides important practical implication. Recently coworker`s supportive attitudes are emphasized as important factor to enhance organizational effectiveness. Therefore, coworker`s engaging in interpersonal helping behaviors are rated positively by fellow employees and positively influence on overall evaluation concerning actor. By the result of our study, however, helping behaviors of individuals high in ability to self-presentation have to be carefully evaluated in that individuals with high ability to self-presentation were better judged as compared with behaviors which they really engaged in. Our study proved that rater high in self-enhancement motives had a weak tendency to evaluate coworker`s helping behaviors as OCB-I. This result indicates that cognitive schema that rater brings to the evaluation process influences the rating of coworker`s interpers

상사의 비인격적 행동과 직무수행 간의 메커니즘에 관한 연구

이수진(Soo Jin Lee),손승연(Seung Yeon Son),김석영(Seck Young Loretta Kim),김보영(Bo Young Kim),윤석화(Seok Hwa Yun) 한국경영학회 2012 經營學硏究 Vol.41 No.3

Although much of the leadership research has focused on constructive leader behaviors, researchers recently has shown their interests in dysfunctional leader behaviors that can be referred as abusive supervision. Furthermore, more studies have reported the growing percentage of abusive supervision in their organization as organizations have been pushed for rapid changes in a competitive environment. For that reason, researchers as well as practitioners have demonstrated their growing concern of this topic. Although the direct negative influence of abusive supervision on organization effectiveness is quite predictable, the current empirical literatures on abusive supervision is very limited that previous studies have only focused on the negative impact of abusive supervision on individual`s well being and there is not much attention to find the negative effect of abusive supervision on job related performances. Drawing on insights from Social Exchange Theory (SET), this research examines the negative consequence of abusive supervision on job related performance, specifically, task performance and organization citizenship behaviors. In order to clarify and investigate the mechanisms between these relationships, trust in leader and psychological contract breach are selected as mediating variables. Out of the process, we developed and empirically tested the following hypotheses: H1a: Abusive supervision is negatively related to task performance. H1b: Abusive supervision is negatively related to OCBI. H1c: Abusive supervision is negatively related to OCBO. H2: Abusive supervision is negatively related to trust in leader. H3: Abusive supervision is positively related to psychological contract breach. H4a: Trust in leader mediates the relationship between abusive supervision and task performance. H4b: Trust in leader mediates the relationship between abusive supervision and OCBI. H4c: Trust in leader mediates the relationship between abusive supervision and OCBO. H5a: Psychological contract breach mediates the relationship between abusive supervision and task performance. H5b: Psychological contract breach mediates the relationship between abusive supervision and OCBI. H5b: Psychological contract breach mediates the relationship between abusive supervision and OCBO. The result of this study showed that abusive supervision was negatively related to employee`s job performance, suggesting the support of Hypothesis 1(a, b, and c). Also, as predicted, the results suggested the negative relationship between abusive supervision and employee`s trust in leader(Hypothesis 2) as well as the positive relationship between abusive supervision and his/her psychological contract breach(Hypothesis 3). Next, to test our hypotheses regarding the mediating role of trust in leader, we adopted the approach suggested by Baron and Kenny (1986). The result of mediation analysis suggested the support of Hypothesis 4(a, b, and c). Finally, our hypotheses regarding the mediating role of psychological contract breach was strongly supported, suggesting the support of Hypothesis 5. This study has implications for theory and practice. First, we contribute to the literature on abusive supervision by demonstrating a negative relationship between abusive supervision and job performance. Second, our research identified an important mechanisms related to how abusive supervision influences the occurrence of employee`s job performance, suggesting the mediating effects of trust in leader and psychological contract breach. Finally, our study demonstrated that abusive supervision can damage the long-term success of the organization by increasing employee`s psychological contract breach and reducing his/her trust in leader. Therefore, organizations need to pay more attention to managing supervisor`s abusive behaviors. Limitations and future research are discussed.

조직공정성이 구성원의 지식공유에 미치는 영향

박희태(Hee Tae Park),이수진(Soo Jin Lee),손승연(Seung Yeon Son),김석영(Seck Young Loretta Kim),윤석화(Seok Hwa Yun) 한국경영학회 2011 經營學硏究 Vol.40 No.2

Knowledge Management is the most important issue in the operation of an organization and it has been widely applied in various types of organization. The essential factor to ensure successful Knowledge Management is knowledge sharing. Knowledge sharing is defined in different ways, in general it means the delivery of knowledge (tacit and explicit), and most studies on knowledge sharing focus on How to motivate subordinates of an organization to share knowledge with others. However, relatively few has been on the organization justice that affects the behavior and attitude of subordinates. Organizational justice can be theoretically considered as an important factor of knowledge sharing. According to the social exchange theory, subordinates who recognize organizational justice tend to exhibit cooperative behavior as a reward. In the respect that knowledge sharing is a kind of cooperative behavior for coworkers, the employees who recognize organizational justice is likely to share knowledge in more effective manners. However, the theory set a limitation for us to explain how subordinates who recognize justice from organization or supervisors share their knowledge to coworkers. So we adopted justice heuristic theory to explain the limitation. According to the justice heuristic theory, knowledge sharing is a social dilemma arising in an organization and being decreased by trust. The theory also says that recognition of organizational justice works as a proxy for trust. Therefore organizational justice as the antecedent to promote knowledge sharing has an important meaning when knowledge sharing is observed from the viewpoint of social dilemma. The purpose of this research is to examine the relationships between organizational justice and knowledge sharing based on this theoretical background. Generally, organization justice was studied in terms of distribution, procedures, and interaction (interpersonal and information). Thus, the first goal of this research is to reveal the relationship between distributional, procedural, and interactional justice (interpersonal justice, informational justice) and knowledge sharing. The second goal is to study the moderating effect of interactional justice (interpersonal justice, informational justice) in the relationships between distributional, procedural justice and knowledge sharing. Therefore we hypothesize: H 1: There is positive relationship between distributional justice and knowledge sharing. H 2: There is positive relationship between procedural justice and knowledge sharing. H 3: There is positive relationship between interactional justice (a: interpersonal justice, b: informational justice) and knowledge sharing. H 4: The interactional justice (a: interpersonal justice, b: informational justice) moderates the positive relationship between distributional justice and knowledge sharing such that the relationship will be stronger when the interactional justice (a: interpersonal justice, b: informational justice) is high than interactional justice (a: interpersonal justice, b: informational justice) is low. H 5: The interactional justice (a: interpersonal justice, b: informational justice) moderates the positive relationship between procedural justice and knowledge sharing such that the relationship will be stronger when the interactional justice (a: interpersonal justice, b: informational justice) is high than interactional justice (a: interpersonal justice, b: informational justice) is low. Data was collected by giving questionnaire to 435 pairs of a supervisor and his/her immediate employee. 360 questionnaires were collected. Among those, 322 dyadic data were used for analysis. The results indicated that distributional justice and interpersonal justice were significantly and positively related to knowledge sharing, but procedural justice and informational justice was not. Besides, there was a significant interaction effect of interactional justice (interpersonal justice, informational

백서 기도 평활근 장력에 미치는 Etomidate 의 효과

김혜자,이정은,손윤숙,윤석화 대한마취과학회 2000 Korean Journal of Anesthesiology Vol.39 No.1

Background : Etomidate is an intravenous anesthetic which has properties of hemodynamic stability, minimal respiratory depression, and cerebral protection. Also, it is a useful induction agent for patients compromised by asthma and other reactive airway diseases. The aim of this study was to investigate the effect and sctioo mechanism of etomidate on isolated tracheal smooth muscle in rats. Methods : The rat's trachea was dissected free, cut into rings (2 mm) and mounted for isometric tension in Tris Tyrode soluticra. Cumolative dose- response curves for etomidate (3 x 10^7 - 3 x 10^(-4)M) were obtained from the tensian measutements of acetylcholine (10^(-5) M)-contracted rings. The effects of propranolol, L-NAME and indomethacin an the etomidate induced tracheal response were investigated. Also, the effect of etomidate on the extracellular Ca^(2-) influx and Ca^(2+)' release from intemal stores was investigated. Results : Etomidate produced relaxation of acetylcholine-ptecontracted trachea in a dose-dependent fashion. Petreatment with propranolol, 1-NAME had no effects on concentration-response curves to acetylcholine. Pretreatment with indomethacin had an effect on the concentration-response curve to acetylcholine. Pretreatment with etomidate inhibited acetylcholine-induced contractions in the absence of extracelluar Ca^(2-) and the presence of extracellular Ca^(2+). Conclusions : The tracheal smooth muscle relaxation by etomidate is not related with beta-adrenergic activation and NO synthesis but related with prostaglandin production. The relaxation effect of etomidate is induced by a decrease in concentration of intracellular Ca^(2+) through the blackade of extracellular Ca^(2+) influx and the simultaneous release of Ca^(2+) from intemal stores. (Korean J Anesthesiol 2000; 39: 105~110)

경막외 Morphine 과 Morphine-Ketamine 혼용주입시 술후 진통효과 비교

김혜자,윤영대,이정은,최세진,윤석화,이상웅 대한마취과학회 2000 Korean Journal of Anesthesiology Vol.39 No.1

Background : Epidural narcotics are now widely used for postoperative pain relief, but their side effects are problematic. Thus, this study was undertaken to evaluate the analgesic effects and to minimize the side effects of the combination of epidural morphine and ketamine versus epidural morphine alone in pateints with postoperative pain. Method : The value of using a combined infusion of morphine with a variable dose of ketamine for postoperative analgesia following subtotal gastrectomy was assessed in a double-blind randomised study of 30 patients. Three groups of 10 patients received an infusion of morphine at 2 mg/day, either alone, or combined with ketamine at a rate of 0.4 or 0,6 mg/kg/day, Results : Postoperative anlagesia, sedation, and side effects were not statistically significantly different between groups I and II. Postoperative sedation, and side effects were not statistically significantly different between groups I and III. VAS of group III at 1-2 h was lower than in group L Conclusion: The addition of ketamine to a continuous infusion of morphine dose not significantly improve postoperative analgesia. In addition, increasing the dose of ketamine does not significantly improve postoperative analgesia, Nor does it increase sedation, or side effects. (Korean J Anesthesiol 2000; 39: 91~97)