1. Department of anesthesiology, Kermanshah University of Medical Sciences, Kermanshah, Iran
2. Department of neurosurgery, Kermanshah University of Medical Sciences, Imam Reza hospital, Kermanshah, Iran
3. Imam Reza hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran
4. Kermanshah University of Medical Sciences, Kermanshah, Iran
5. Imam Reza hospital, Nursing and midwifery school, Kermanshah University of Medical Sciences, Kermanshah, Iran