Teaching and learning of difficult airway management are considered to be an essential skill in anesthesiology. As a result, doctors and nurses in anesthesia have to be vigilant in every step including airway assessment, equipment preparation and strategic planning of the process.

During the one-year training program, nurse anesthetist students intensively study theories and practical skills in anesthesia, using manikins to living patients. Difficult airway management has become a distinguished means in the training curriculum. In addition, the educational tool in the anesthesia curriculum is typically simulation-based learning (SBL) and problem-based learning (PBL) courses. As a result, we designed a cross-over study to determine the learning achievement of nurse anesthetist students in difficult airway management. The objectives were to study the learning achievement and relative growth of knowledge of the two learning techniques: SBL and PBL.

Thirty-six nurse anesthetist students in Academic Year 2015, volunteered to join the study project. After signing the consent form, they were randomly put into two groups: A (n = 17) and B (n = 19). As designed by the cross-over study, students in group A attended SBL and after 6 weeks, they focused on PBL, and vice versa for group B.

The 40-item, multiple choices exam was developed in regard to difficult airway management guidelines. The correctness and appropriateness of the test (content validity) were determined by three board-certified anesthesiologists. The try out of the test was performed by 10 novice nurse anesthetists. The index of item objective congruence was 0.82 with Kuder Richardson 21 of 0.8. The assessed criterion-referenced item difficulty and discrimination index were 0.4-0.6 and 0.6-0.8 respectively.

The pretest (X1, X2) were post-test ((Y1, Y2) were performed in the consequence. The relative growth of knowledge (G1, G2) was calculated as follows:

G1 = 100 (Y1 - X1) / (F - X1) % G2 = 100 (Y2 - X2) / (F - X2) %

Where F was the full scores of the learning course

Statistics analysis The test scores and relative growth of knowledge between the two groups were expressed as mean and standard deviation. Comparison between the two groups was performed by repeated measure ANOVA. Statistically significant differences were considered when there was a p value of < 0.05 with a 95% confidence interval.

Introduction Teaching and learning of difficult airway management are considered to be an essential skill in anesthesiology. Assessment of the training program requires a currently established guideline. Recent studies revealed that the management of the airway was the most sophisticated maneuver for all anesthesia providers, since it is related to morbidity and mortality circumstances. It appeared in 6.2% of endotracheal intubations in the operating theater. In addition, difficult intubation with ventilation occurred in 1.5%, of the procedures; impossible intubation and difficult ventilation 0.3 %; and "can't intubate, can't ventilate" (CICV) situation, 0.07%.

Normally, most anesthesia personnel perform endotracheal intubation under general anesthesia. However, they occasionally come across difficult airways. This becomes a life- and-death condition that may lead to uneventful sequelae. In practice, a difficult airway is defined as either troublesome facemask ventilation or tracheal intubation. As a result, doctors and nurses in anesthesia have to be vigilant in every step including airway assessment, equipment preparation and strategic planning of the process. In addition, updated difficult airway algorithm helps them manage the patient's airway at the right time.

After graduation, registered nurses need to spend one more year on a training program to become nurse anesthetists, serving as either an anesthesiologist's assistant or a general practitioner's helper. During the one-year training program, nurse anesthetist students intensively study theories and practical skills in anesthesia, using manikins to living patients. However, effective training in airway management results from the learners' competences and from a diversity of teaching techniques.

Currently, the educational tool in the anesthesia curriculum is typically simulation-based learning (SBL) and problem-based learning (PBL) courses, both of which have been widely accepted in many educational institutes. They yield a promising outcome amongst students of professionalism. The SBL provides high-level learning circumstances to help students gain their experiences. The diagnostic and feedback system help learners correct their mistakes with confidence. However, PBL allows students to present their informative knowledge, resulting in retention and integration of learning with clinical experience. In addition, self-directed learning gives them creative thinking. Instructors act as facilitators who empower students to implement their own strategic plan of learning.

Either SBL or PBL has its unique process to assess participants' core knowledge. Furthermore, difficult airway management has become a distinguished means in the training curriculum. As a result, we designed a cross-over study to determine the learning achievement of nurse anesthetist students in difficult airway management.

Objectives To study the learning achievement and relative growth of knowledge of the two learning techniques: SBL and PBL.

Methods Thirty-six nurse anesthetist students in Academic Year 2015, Department of Anesthesiology, Faculty of Medicine Siriraj Hospital, Mahidol University, volunteered to join the study project without any honorarium. The benefit of taking part in the study was only knowledge and clinical experience gained. The students were informed about the significance of the research under the faculty policy as well as the learning objectives in details. After signing the consent form, they were randomly put into two groups: A (n = 17) and B (n = 19). As designed by the cross-over study, students in group A attended SBL and after 6 weeks, they focused on PBL, and vice versa for group B.

The PBL learning session comprised four different clinical questions together with educational resources for one hour self-study. Consequently, all students spent two more hours on presentation and discussion of knowledge information in front of the class. The SBL learning session consisted of the same clinical scenarios as PBL. All learners spent three hours in the environment of a well-equipped operating theater with a standardized patient or a high-fidelity manikin. Then they joined the debriefing forum given by an attending staff.

The 40-item, multiple choices exam was developed under the table of specifications and knowledge map in regard to difficult airway management guidelines. The paper-pencil test comprised of evaluation of the airway, basic preparation of difficult airway management, strategy of endotracheal intubation and extubation, and follow up care.

The correctness and appropriateness of the test (content validity) were determined by three board-certified anesthesiologists who had at least 10 years of experience in anesthesia and were not involved in the project. The try out of the test was performed by 10 novice nurse anesthetists. The index of item objective congruence was 0.82 with Kuder Richardson 21 of 0.8. The assessed criterion-referenced item difficulty and discrimination index were 0.4-0.6 and 0.6-0.8 respectively.

The pretest (X1, X2) were post-test ((Y1, Y2) were performed in the consequence. The relative growth of knowledge (G1, G2) was calculated as follows:

G1 = 100 (Y1 - X1) / (F - X1) % G2 = 100 (Y2 - X2) / (F - X2) %

Where F was the full scores of the learning course

Statistics analysis The test scores and relative growth of knowledge between the two groups were expressed as mean and standard deviation. Comparison between the two groups was performed by repeated measure ANOVA using the Statistical Package for Social Sciences for Windows, release 18. Statistically significant differences were considered when there was a p value of < 0.05 with a 95% confidence interval.

Inclusion Criteria:

• Nurse anesthetist students in the academic year of 2015

Exclusion Criteria:

• The unwilling nurse anesthetist students in the academic year of 2015