Effect of first epinephrine administration time on cerebral perfusion pressure and cortical cerebral blood flow in a porcine cardiac arrest model.

OBJECTIVE: The optimal time for epinephrine administration and its effects on cerebral blood flow (CBF) and microcirculation remain controversial. This study aimed to assess the effect of the first administration of epinephrine on cerebral perfusion pressure (CePP) and cortical CBF in porcine cardiac arrest model. METHODS: After 4 min of untreated ventricular fibrillation, eight of 24 swine were randomly assigned to the early, intermediate, and late groups. In each group, epinephrine was administered intravenously at 5, 10, and 15 min after cardiac arrest induction. CePP was calculated as the difference between the mean arterial pressure and intracranial pressure. Cortical CBF was measured using a laser Doppler flow probe. The outcomes were CePP and cortical CBF measured continuously during cardiopulmonary resuscitation (CPR). Mean CePP and cortical CBF were compared using analysis of variance and a linear mixed model. RESULTS: The mean CePP was significantly different between the groups at 6-11 min after cardiac arrest induction. The mean CePP in the early group was significantly higher than that in the intermediate group at 8-10 min and that in the late group at 6-9 min and 10-11 min. The mean cortical CBF was significantly different between the groups at 9-11 min. The mean cortical CBF was significantly higher in the early group than in the intermediate and late group at 9-10 min. CONCLUSION: Early administration of epinephrine was associated with improved CePP and cortical CBF compared to intermediate or late administration during the early period of CPR.

Usability testing of a blind intubation device for intubation novices: a randomized crossover simulation study.

OBJECTIVE: A new blind intubation device (BID) has been developed for endotracheal intubation. This study aimed to test the usability of the BID in comparison to direct laryngoscopy (DL) and video laryngoscopy (VL) with inexperienced healthcare providers for endotracheal intubation. METHODS: This was a randomized crossover simulation study. Participants who had conducted fewer than five live intubation sessions were included in the study. The manikin simulation was conducted using a Laerdal trainer airway manikin. Participants performed intubation using all three devices, DL, VL, and BID. The primary outcome was intubation success rate in the first pass the secondary outcome was intubation time to first ventilation, and the tertiary outcome was dental injury. RESULTS: A total of 45 healthcare workers who were novices in intubation participated in this study, including 13 physicians (interns), 14 emergency medical technicians, and 18 nurses. The intubation success rates in the first pass with BID, DL, and VL were 93.3%, 91.1%, and 97.8%, respectively (P=0.53). The intubation times to first ventilation with BID, DL, and VL were 13.15±6.16, 19.07±7.71, and 17.31±6.57 seconds, respectively (P<0.01). The proportions of dental injuries associated with BID, DL, and VL were 0% for physicians; 28.6%, 14.3%, and 0%, respectively for emergency medical technicians; and 27.8%, 11.1%, and 16.7%, respectively for nurses. CONCLUSION: We performed a pilot study to test the usability of the new BID. There was no significant difference in intubation success rate in the first pass among BID, DL, and VL. The intubation time to first ventilation was shorter with the BID compared to DL and VL.

Nasal and temporal curvatures of lamina CRIBROSA in myopic eyes.

Little is known about the myopic characteristics of lamina cribrosa (LC) curvature. As such, we investigated nasal and temporal LC curvatures in myopia. In this retrospective, cross-sectional study, 144 myopic eyes (refraction < - 2D) and 88 non-myopic eyes (refraction > - 0.5D) underwent swept-source optical coherence tomography scanning of the LC. The anterior border of LC curvature was delineated with 17 points and interpolated with the "cardinal spline" curve-fitting method. The average curvature indices of the temporal and nasal sides were presented as the temporal and nasal curvatures. Myopic eyes had a mean refraction of - 6.7 ± 2.8D, while for non-myopic eyes, the value was 0.3 ± 1.0D. Nasal LC curvature was visible in 54 myopia (37.5%) and 42 non-myopia (47.7%) cases (P = 0.126), and temporal LC curvature was visible in 142 myopia (98.6%) and 68 non-myopia (77.3%) cases (P = 0.001). The nasal LC curvature was significantly larger in myopia than in non-myopia (P < 0.001). Contrastingly, the temporal LC curvature was significantly smaller in myopia than in non-myopia (P < 0.001). Axial length was associated with larger nasal LC curvature, smaller temporal LC curvature, and larger nasal-temporal LC curvature difference (all P's < 0.05). In myopic relative to non-myopic eyes, LC curvature was decreased temporally and increased nasally.

Novel Simulation Model That Realizes Arterial and Venous Blood Flow for Ultrasound-Guided Central Venous Catheter Insertion in Children.

OBJECTIVE: We developed and validated a realistic simulation model for ultrasound-guided central venous catheter insertion in children that is easy to build and inexpensive and can automatically reproduce arterial and venous blood flow. METHODS: The simulation model was constructed with a chicken breast, two DWP-385 water pumps, two types of tubes and a controller. An elastic rubber tourniquet and a silicone tube were connected to each water pump, which generated different continuous flows mimicking those of the pediatric internal carotid artery and internal jugular vein, respectively. Both tubes were inserted into a piece of chicken breast and connected to the controller. Then, we provided a simulation program of ultrasound-guided central venous catheter insertion using our novel model to resident emergency medicine physicians. We also collected data on their knowledge and confidence levels regarding the procedure before and after the simulation via questionnaires utilizing a 5-point Likert scale. RESULTS: The flow patterns of the artery and vein were well demonstrated with our model. A total of 11 resident physicians were enrolled. The knowledge and confidence regarding the discrimination of arteries and veins were significantly improved after training with our simulation model (p-value < 0.01). The subjective similarity and usefulness of our model also scored high on the questionnaire (median: 4; interquartile range in both categories: 4-5). CONCLUSION: Our novel simulation model is useful and realistic for ultrasound-guided central venous catheter insertion training. Clinical impact: This controlled motor system can be applied to many simulation models of artery and vein circulation.

3D-Printed Ophthalmic-Retrobulbar-Anesthesia Simulator: Mimicking Anatomical Structures and Providing Tactile Sensations.

Objective: A simulator for retrobulbar anesthesia administration mimicking the orbital anatomy and providing tactile sensation is proposed. Methods: The production process involves 3D modeling of anatomical structures on the basis of computerized tomography (CT) images, printing the models using a 3D printer, and casting the silicone. Twenty ophthalmologists administered retrobulbar anesthesia using the simulator with four different ocular axial lengths (including extreme myopes); the position of the needle tip was evaluated. The effectiveness of this simulator for training was also surveyed. Results: The proportions of the final location of the needle tip were 59.25%, 36.25%, and 4.5% for the retrobulbar space, peribulbar space, and intraocular space, respectively. Experienced ophthalmologists showed lower complication rates than residents (0.5% vs 8.5%, [Formula: see text]) and agreed that this simulator will help young ophthalmologists advance their anesthesia-administering skills. Discussion/Conclusion: The 3D-printered simulator for retrobulbar anesthesia was produced and performance was verified. The technology could be used to simulate critical orbital anatomic features and could be used as a training tool for resident ophthalmologists.

Validation of digital tourniquet pressures: An experimental comparison of T-RingTM and conventional surgical glove in human volunteers.

Digital tourniquets are widely used for the management of digital injuries in emergency departments or outpatient clinics. This study is focused on the pressure analysis of digital tourniquets on some points not covered in the existing literature.A total of thirty volunteers were enrolled in this study. Instantaneous surface pressure was measured at the thumbs, index fingers, and little fingers. We investigated the pressure according to the circumference of digits, tourniquet types, and measurement sites (dorsal and mid lateral volar sides) above the digital vessels. Continuous pressure was measured in artificial silicone models to determine the change of pressure over 2 hours.The average pressure measured on the mid lateral volar side of volunteers fingers were 154.3 ± 54.9 mm Hg by T-Ring and 162.6 ±â€Š61.0 mm Hg by surgical glove. The pressure on the dorsal side were 224.7 ±â€Š57.7 mm Hg by T-Ring and 228.8 ±â€Š66.0 mm Hg by surgical glove, each significantly higher than the mid lateral volar side. The circumference of digits did not significantly affect the surface pressure. The pressure pattern did not change significantly over 2 hours in both tourniquet types.The surface pressure of the mid lateral volar side was significantly lower than that of the dorsal side. However, there was no significant pressure difference according to the circumference of digits. Time dependent pressure change were not significantly different between 2 tourniquets.

Total body irradiation with a compensator fabricated using a 3D optical scanner and a 3D printer.

We propose bilateral total body irradiation (TBI) utilizing a 3D printer and a 3D optical scanner. We acquired surface information of an anthropomorphic phantom with the 3D scanner and fabricated the 3D compensator with the 3D printer, which could continuously compensate for the lateral missing tissue of an entire body from the beam's eye view. To test the system's performance, we measured doses with optically stimulated luminescent dosimeters (OSLDs) as well as EBT3 films with the anthropomorphic phantom during TBI without a compensator, conventional bilateral TBI, and TBI with the 3D compensator (3D TBI). The 3D TBI showed the most uniform dose delivery to the phantom. From the OSLD measurements of the 3D TBI, the deviations between the measured doses and the prescription dose ranged from -6.7% to 2.4% inside the phantom and from -2.3% to 0.6% on the phantom's surface. From the EBT3 film measurements, the prescription dose could be delivered to the entire body of the phantom within ±10% accuracy, except for the chest region, where tissue heterogeneity is extreme. The 3D TBI doses were much more uniform than those of the other irradiation techniques, especially in the anterior-to-posterior direction. The 3D TBI was advantageous, owing to its uniform dose delivery as well as its efficient treatment procedure.