Richard R. Kyle

Insertion forces and risk of complications during cricothyroid cannulation

Our purpose was to determine the forces required to insert several different styles of cricothyroid cannulas and to relate the magnitude of these forces and cannula design features to the incidence of complications during insertion. Tests were done on unembalmed cadavers and anesthetized dogs. Samples of 4 different commercial cricothyroid cannulas were tested. Each cannula type was tested in 5 different cadavers and 10 different dogs. A lubricant was applied to the cannulas in half of the dogs tested. Major findings are 1) there is a linear correlation between insertion force and device diameter, 2) higher puncture force is associated with a greater incidence of complications, 3) posterior wall penetration occurs more frequently with a curved penetrating device, 4) using small pilot needles to guide insertion of large cannulas minimizes complications, and 5) lubricant is less effective for cannulas having abrupt diameter changes. These findings provide guidelines for design of safer cricothyroid cannulas.

Establishing a Convention for Acting in Healthcare Simulation Merging Art and Science

Summary Statement Among the most powerful tools available to simulation instructors is a confederate. Although technical and logical realism is dictated by the simulation platform and setting, the quality of role playing by confederates strongly determines psychological or emotional fidelity of simulation. The highest level of realism, however, is achieved when the confederates are properly trained. Theater and acting methodology can provide simulation educators a framework from which to establish an acting convention specific to the discipline of healthcare simulation. This report attempts to examine simulation through the lens of theater arts and represents an opinion on acting in healthcare simulation for both simulation educators and confederates. It aims to refine the practice of simulation by embracing the lessons of the theater community. Although the application of these approaches in healthcare education has been described in the literature, a systematic way of organizing, publicizing, or documenting the acting within healthcare simulation has never been completed. Therefore, we attempt, for the first time, to take on this challenge and create a resource, which infuses theater arts into the practice of healthcare simulation.

A path to better healthcare simulation systems: leveraging the integrated systems design approach.

This article addresses the necessary steps in the design of simulation-based instructional systems. A model for designing instructional systems is presented which stipulates that the outcome metrics be defined before the simulation system is designed. This ensures integration of educational objectives and measures of competency into the design and development process. The article ends with a challenge to simulator users and instructors: become involved in the integrated system design process by the daily collection of standardized data and working with the simulation engineers throughout the design process.

Effects of Soman (Pinacolyl Methylphosphonofluoridate) on Coronary Blood Flow and Cardiac Function in Swine

The effects of soman (pinacolyl methylphosphonofluoridate) on coronary blood flow, the electrocardiogram, and cardiac function were measured in alpha-chloralose-anesthetized swine. Coronary blood flow (CBF), mean arterial blood pressure (MAP), peak systolic left ventricular pressure (IVP), maximum rate of left ventricular pressure development (dP/dtmax), cardiac output, and the ECG were monitored continuously. A dose of 2X LD50 of soman (1 LD50 = 4.6 micrograms/kg) was given at 1 LD50/min in the femoral vein, which produced an increase in coronary sinus plasma acetylcholine (ACh) from a control of 0.7 +/- 0.01 nmol/ml to a maximum 314% of control at 15 min and a decrease in CBF from a control of 99 +/- 13 ml/min/100 g to a minimum 55% of control at 15 min. The increase in ACh in the coronary sinus was significantly correlated with a decrease in CBF (r = -0.87, p < 0.001). The fall in CBF was accompanied by concomitant decreases in IVP, MAP, and dP/dtmax, with S-T segment elevation and ventricular fibrillation. The increase in coronary sinus acetylcholine concentration was significantly correlated with a 10-fold fall in coronary sinus acetylcholinesterase levels from a control of 2.47 +/- 0.97 mol acetylcholine hydrolyzed/ml blood/min and was consistent with the time course for the reduced hemodynamic measurements. These studies support the hypothesis that acetylcholine increases following soman toxicity may decrease coronary blood flow, thereby initiating ischemic electrocardiographic changes and reducing cardiac function.

Pulmonary Mechanical Responses to Cholinesterase Inhibitor

Lung static and dynamic compliances, and lung and upper airway resistances were measured in pentobarbital-anesthetized dogs before and after intravenous administration of 2 LD50 of the organophosphate cholinesterase inhibitor pinacolyl methylphosphonofluoridate (GD), followed by 1 mg of atropine 8 min later. Dynamic compliances and resistances were estimated by a linear regression model and by a Fourier analysis technique, with the two methods giving comparable results. GD caused a maximum increase in lung resistance of about 20 times control values, and about an 80% decrease in lung dynamic compliance. Frequency dependence of lung compliance and resistance was increased by GD administration. Following GD administration, upper airway opening pressure increased, indicating the presence of laryngospasm. Upper airway resistance during the latter portion of the breath, when the airway was open, decreased after GD administration, concurrent with the increase in carinal pressure that occurred as the result of increased lung impedance. These results suggest that the GD-induced decrease in upper airway resistance was due to passive distension of the upper airway. Physiological deadspace decreased by a maximum of about 65% following GD administration. Administration of atropine resulted in a prompt and almost complete reversal of all of the GD-induced effects on pulmonary mechanical properties and ventilation. The results of this study suggest that the major pulmonary mechanical effects of GD in the dog are caused by constriction of smooth muscle at different levels of the respiratory tract.

Determinants of alveolar ventilation during high-frequency transtracheal jet ventilation in dogs.

The effectiveness of transtracheal jet ventilation is a function of gas delivery pressure (drive pressure), duty cycle (insufflation time/total cycle time), and respiratory frequency. Nine dogs, anesthetized with sodium pento-barbital, were ventilated through a cricothyrotomy cannula using a controller that allowed separate setting of drive pressure, duty cycle, and frequency. Pao2 and PaCO2 were measured after achieving steady-state gas exchange at 15 to 22 different combinations of drive pressure, duty cycle, and frequency in each dog. There were slight increases in Paco2 and larger decreases in Pao2 as frequency was increased from 10 to 200 cycle/ min. Increases in drive pressure and duty cycle resulted in reduced Paco2 and increased Pao2. Multiple linear regression showed good correlation between Paco2 and drive pressure, duty cycle, and frequency. The distribution of air flow between alveolar and physiologic dead space, upper airway leakage, and entrainment was determined for each set of conditions. Changes in alveolar ventilation corresponding to the blood gas changes resulted from interaction of dead-space ventilation and upper airway leakage, which varied with breath duration. Decreases in leakage during short breaths tended to compensate for the increased fractional dead-space ventilation at high frequency, thus minimizing the effects of frequency changes on gas exchange.

Differential response of dog and pig tracheal smooth muscle to the acetylcholinesterase inhibitor soman

The effect of the acetylcholinesterase inhibitor soman on tracheal smooth muscle (TSM) from the dog and pig was studied. In response to soman, tracheal ring preparations contract more and the resting tension for TSM preparations is higher for the dog compared with the pig. Tension induced by electrical field stimulation (EFS) and the half-time of EFS-train induced contractions have a similar dependence on soman exposure in both dog and pig TSM. These results suggest that the basal acetylcholine secretion or leakage within the TSM nerve terminal is probably higher for the dog compared with the pig.

A simple algorithm for averaging multiple cycles of waveforms having varying cycle periods

We present a simple method for averaging multiple cycles of a waveform having cycles with varying periods. This averaging process preserves the morphology of the waveform by converting fixed time per point data into fixed fraction of cycle data. The algorithms are implemented using the ASYST system, which provides efficient code for performing the computations and permits straightforward integration of the data acquisition and analysis tasks. An example is given of the results of the program in processing cyclical waveforms obtained in respiratory research.

Simulation II: Preparing for Biodisasters

Publisher Summary The aim of this chapter is to apply principles of designing and to produce simulation scenarios. It deals with the identification of technical and personnel resources, required for a successful biodisaster preparation program. During a real biodisaster, confidence in ones own competence as well as in the abilities of the rest of the team is a vital prerequisite for any expectation of a successful response. Engaging in scheduled simulated disasters gives treatment-center personnel invaluable learning experiences for improbable biodisasters. The disasters can be overwhelming tsunami-like invasions. The product of their great size and very rapid onset characterizes the magnitude of their power for devastation. Formal didactic instruction and on-the-job experiential learning during “normal” situations are inadequate preparations for disasters, especially those that are intentionally created. Simulation in various forms can reveal the gaps in the current disaster preparation and can provide methods for exploring the various new approaches to fill those gaps.