• 한국응급구조학회지
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• 제18권2호
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• pp.35-43
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• 2014

Purpose: The purpose of this study was to establish novice user guidelines for efficient external laryngeal manipulation for intubation in difficult airway management. Methods: This study included 59 pre-qualified junior and senior emergency medical service students. The participants were instructed at random to intubate a manikin equipped with a cervical collar, thus simulating a difficult airway, using three types of external laryngeal manipulation: bimanual laryngoscopy, backward-rightward pressure, and cricoid pressure. The resultant intubation time and glottic view grade scores were estimated. Results: Intubation time was longest using the bimanual manipulation method, followed by cricoid pressure and backward-rightward pressure. A low Cormack-Lehane glottic view score was obtained regardless of the assisted compression method used. Conclusion: Backward-rightward pressure may be the most efficient method of external laryngeal manipulation on the basis of the intubation time and improvement in glottic view.

• 대한인간공학회지
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• 제34권4호
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• pp.313-326
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• 2015

Objective: The objective of this research is to quantitatively analyze muscle activities of arm and shoulder, according to direction in various types of one-handed manual material handling, based on surface electromyography. Background: Workers in industrial sites frequently carry out one-handed manual material handling using arm and shoulder muscles. Therefore, chronic load and accumulated fatigue occur to arm and shoulder muscles, which becomes a main cause of upper arm and shoulder musculoskeletal disorders. The shoulder muscles have widely range of motion, and complex interactions take place among various muscles including rotator cuff muscles. In this regard, research on interactions among should muscles, according to such various dynamic motions, is required. Method: Ten male subjects in their 20s participated in this research. This research considered upward, downward, leftward, rightward, forward and backward directions and fourteen muscles around arm and shoulder (biceps brachii and trapezius, etc.) as independent variables. The mean muscle activity was set as the dependent variable. This research extracted $4^{th}{\sim}7^{th}$ repetition signals according to ten times of repetitive muscle contraction, and analyzed the muscle activity concerned using the envelope detection technique. Results: The mean muscle activity of upward direction was analyzed highly statistically significant. The reason is that the effect of gravity works to arm and shoulder muscles. Also, it is conjectured that deformation of coracoacromial ligament was caused, and its contact pressure increased, due mainly to the shoulder flexion, and therefore load was analyzed high. Muscle activity was analyzed significantly low, according to concentric ballistic motion used in the concentric contraction phase by storing elastic energy in the eccentric contraction phase with a motion to bring the weight to the front of subject's body as to downward, leftward and backward directions. Because, elbow joint's flexion-extension motions mainly occurred, biceps brachii was analyzed high muscle activity as the prime mover. Conclusion: The information on the quantitative load of muscles can be applied to ergonomic work design for one-handed manual material handling to minimize muscle load. Application: This research has effectively identified muscle activity according to dynamic contraction by applying an envelope detection technique. The results can be used for ergonomic work design to minimize muscle load during the one-handed manual material handling, according to each direction. The research results are expected to be used for musculoskeletal disorder prevention and physiotherapy in the rehabilitation medical field, based on the muscle load of arm and shoulder in various directions.