Johannes Prottengeier

The effect of a standardised source of divided attention in airway management: A randomised, crossover, interventional manikin study.

BACKGROUND Dual-tasking, the need to divide attention between concurrent tasks, causes a severe increase in workload in emergency situations and yet there is no standardised training simulation scenario for this key difficulty. OBJECTIVES We introduced and validated a quantifiable source of divided attention and investigated its effects on performance and workload in airway management. DESIGN A randomised, crossover, interventional simulation study. SETTING Center for Training and Simulation, Department of Anaesthesiology, Erlangen University Hospital, Germany. PARTICIPANTS One hundred and fifty volunteer medical students, paramedics and anaesthesiologists of all levels of training. INTERVENTIONS Participants secured the airway of a manikin using a supraglottic airway, conventional endotracheal intubation and video-assisted endotracheal intubation with and without the Paced Auditory Serial Addition Test (PASAT), which served as a quantifiable source of divided attention. MAIN OUTCOME MEASURES Primary endpoint was the time for the completion of each airway task. Secondary endpoints were the number of procedural mistakes made and the perceived workload as measured by the National Aeronautics and Space Administrations task load index (NASA-TLX). This is a six-dimensional questionnaire, which assesses the perception of demands, performance and frustration with respect to a task on a scale of 0 to 100. RESULTS All 150 participants completed the tests. Volunteers perceived our test to be challenging (99%) and the experience of stress and distraction true to an emergency situation (80%), but still fair (98%) and entertaining (95%). The negative effects of divided attention were reproducible in participants of all levels of expertise. Time consumption and perceived workload increased and almost half the participants make procedural mistakes under divided attention. The supraglottic airway technique was least affected by divided attention. CONCLUSION The scenario was effective for simulation training involving divided attention in acute care medicine. The significant effects on performance and perceived workload demonstrate the validity of the model, which was also characterised by high acceptability, technical simplicity and a novel degree of standardisation.

The prehospital intravenous access assessment: a prospective study on intravenous access failure and access delay in prehospital emergency medicine.

Objectives Intravenous access in prehospital emergency care allows for early administration of medication and extended measures such as anaesthesia. Cannulation may, however, be difficult, and failure and resulting delay in treatment and transport may have negative effects on the patient. Therefore, our study aims to perform a concise assessment of the difficulties of prehospital venous cannulation. Methods We analysed 23 candidate predictor variables on peripheral venous cannulations in terms of cannulation failure and exceedance of a 2 min time threshold. Multivariate logistic regression models were fitted for variables of predictive value (P<0.25) and evaluated by the area under the curve (AUC>0.6) of their respective receiver operating characteristic curve. Results A total of 762 intravenous cannulations were enroled. In all, 22% of punctures failed on the first attempt and 13% of punctures exceeded 2 min. Model selection yielded a three-factor model (vein visibility without tourniquet, vein palpability with tourniquet and insufficient ambient lighting) of fair accuracy for the prediction of puncture failure (AUC=0.76) and a structurally congruent model of four factors (failure model factors plus vein visibility with tourniquet) for the exceedance of the 2 min threshold (AUC=0.80). Conclusion Our study offers a simple assessment to identify cases of difficult intravenous access in prehospital emergency care. Of the numerous factors subjectively perceived as possibly exerting influences on cannulation, only the universal – not exclusive to emergency care – factors of lighting, vein visibility and palpability proved to be valid predictors of cannulation failure and exceedance of a 2 min threshold.

Adverse airway events in parturient compared with non-parturient patients. Is there a difference? Results from a quality management project

The fear of airway problems often leads to prolonged attempts to obtain neuroaxial (spinal anesthesia or epidural anesthesia) anesthesia in obstetric anesthesia. The aim of this institutional quality management study was to revisit existing anesthesia care in the obstetric department, focusing on the frequency of delayed or failed neuroaxial anesthesia as well as the risk of airway problems in parturient and non‐obstetric patients.

Sedation assessment in a mobile intensive care unit: a prospective pilot-study on the relation of clinical sedation scales and the bispectral index

IntroductionThe critically-ill undergoing inter-hospital transfers commonly receive sedatives in continuation of their therapeutic regime or to facilitate a safe transfer shielded from external stressors. While sedation assessment is well established in critical care in general, there is only little data available relating to the special conditions during patient transport and their effect on patient sedation levels. The aim of this prospective study was to investigate the feasibility and relationship of clinical sedation assessment (Richmond Agitation-Sedation Scale (RASS)) and objective physiological monitoring (bispectral index (BIS)) during patient transfers in our Mobile-ICU.MethodsThe levels of sedation of 30 pharmacologically sedated patients were evaluated at 12 to 17 distinct measurement points spread strategically over the course of a transfer by use of the RASS and BIS. To investigate the relation between the RASS and the BIS, Spearman’s squared rank correlation coefficient (ρ2) and the Kendall’s rank correlation coefficient (τ) were calculated. The diagnostic value of the BIS with respect to the RASS was investigated by its sensitivity and positive predictive value for possible patient awakening. Therefore, measurements were dichotomized considering a clinically sensible threshold of 80 for BIS-values and classifying RASS values being nonnegative.ResultsSpearman’s rank correlation resulted to ρ2 = 0.431 (confidence interval (CI) = 0.341 to 0.513). The Kendall’s correlation coefficient was calculated as τ = 0.522 (CI = 0.459 to 0.576). Awakening of patients (RASS ≥0) was detected by a BIS value of 80 and above with a sensitivity of 0.97 (CI = 0.89 to 1.00) and a positive predictive value of 0.59 (CI = 0.45 to 0.71).ConclusionsOur study demonstrates that the BIS-Monitor can be used for the assessment of sedation levels in the intricate environment of a Mobile-ICU, especially when well-established clinical scores as the RASS are impracticable. The use of BIS is highly sensitive in the detection of unwanted awakening of patients during transfers.

Increased Rate of Poor Laryngoscopic Views in Patients Scheduled for Cardiac Surgery Versus Patients Scheduled for General Surgery: A Propensity Score-Based Analysis of 21,561 Cases.

OBJECTIVES Former analyses reported an increased rate of poor direct laryngoscopy view in cardiac surgery patients; however, these findings frequently could be attributed to confounding patient characteristics. In most of the reported cardiac surgery cohorts, the rate of well-known risk factors for poor direct laryngoscopy view such as male sex, obesity, or older age, were increased compared with the control groups. Especially in the ongoing debate on anesthesia staff qualification for cardiac interventions outside the operating room a detailed and stratified risk analysis seems necessary. DESIGN Retrospective, anonymous, propensity score-based, matched-pair analysis. SETTING Single-center study in a university hospital. PARTICIPANTS No active participants. Retrospective, anonymous chart analysis. INTERVENTIONS The anesthesia records of patients undergoing cardiac surgery in a period of 6 consecutive years were analyzed retrospectively. The results were compared with those of a control group of patients who underwent general surgery. Poor laryngoscopic view was defined as Cormack and Lehane classification grade 3 or 4. MEASUREMENTS AND MAIN RESULTS The records of 21,561 general anesthesia procedures were reviewed for the study. The incidence of poor direct laryngoscopic views in patients scheduled for cardiac surgery was significantly increased compared with those of the general surgery cohort (7% v 4.2%). Using propensity score-based matched-pair analysis, equal subgroups were generated of each surgical department, with 2,946 patients showing identical demographic characteristics. After stratifying for demographic characteristics, the rate of poor direct laryngoscopy view remained statistically significantly higher in the cardiac surgery group (7.5% v 5.7%). CONCLUSIONS Even with stratification for demographic risk factors, cardiac surgery patients showed a significantly higher rate of poor direct laryngoscopic view compared with general surgery patients. These results should be taken into account for human resource management and distribution of difficult airway equipment, especially when cardiac interventional programs are implemented in remote hospital locations.

Anaesthesia and orphan disease: fragile X syndrome (Martin-Bell syndrome).

disturbances, have been reported; at autopsy, myocardial and valvular storage of lipopigments have been observed histologically and associated with hypertrophy and dilation of ventricles, degenerative myocardial changes, interstitial fibrosis and fatty replacement. Abundant accumulation of lipopigments and degeneration were seen in all components of the conduction system. Bradycardia, sinus arrest and severe supraventricular tachycardia during anaesthesia in patients with JNCL have also been reported. Some episodes of bradycardia were associated with hypothermia and were successfully treated with anticholinergics. Therefore, preoperative ECG and echocardiography in patients with NCL are considered essential.

Comparison of Metal and Plastic Disposable Laryngoscope Blade with Reusable Macintosh Blade in Difficult and Inhalation Injury Airway Scenario: A Manikin Study.

BACKGROUND Single-use plastic blades (SUPB) and single-use metal blades (SUMB) for direct laryngoscopy and tracheal intubation have not yet been compared with reusable metal blades (RUMB) in difficult airway scenarios. OBJECTIVE The purpose of our manikin study was to compare the effectiveness of these different laryngoscope blades in a difficult airway scenario, as well as in a difficult airway scenario with simulated severe inhalation injury. METHODS Thirty anesthetists performed tracheal intubation (TI) with each of the three laryngoscope blades in the two scenario manikins. RESULTS In the inhalation injury scenario, SUPB were associated with prolonged intubation times when compared with the metal blades. In the inhalation injury scenario, both metal laryngoscope blades provided a quicker, easier, and safer TI. In the difficult airway scenario, intubation times were significantly prolonged in the SUPB group in comparison to the RUMB group, but there were no significant differences between the SUPB and the SUMB. In this scenario, the RUMB demonstrated the shortest intubation times and seems to be the most effective device. CONCLUSIONS Generally, results are in line with previous studies showing significant disadvantages of SUPB in both manikin scenarios. Therefore, metal blades might be beneficial, especially in the airway management of patients with inhalation injury.

Does it matter who places the intravenous? An inter-professional comparison of prehospital intravenous access difficulties between physicians and paramedics.

Objectives Depending on the specific national emergency medical systems, venous cannulations may be performed by physicians, paramedics or both alike. Difficulties in the establishment of vascular access can lead to delayed treatment and transport. Our study investigates possible inter-professional differences in the difficulties of prehospital venous cannulation. Methods Paramedics were interviewed for their personal attitudes towards and experiences in venous access. We analysed 47 candidate predictor variables in terms of cannulation failure and exceedance of a 2 min time threshold. Multivariable logistic regression models were fitted for variables of potential predictive value (P<0.25) and evaluated by the area under the curve (AUC>0.60) of their respective receiver operating characteristic curve. Results were compared with previously published data from emergency physicians. Results A total of 552 cannulations were included in our study. All 146 participants voted that paramedics should be eligible to perform venous catheterizations. Despite ample experience in the task, almost half of them considered prehospital venous cannulations more difficult than those performed in hospital. However, the multivariable logistic regression found only patient-related and puncture site factors to be predictive of cannulation failure (patient age, vein palpability with tourniquet, insufficient ambient lighting: model AUC: 0.72) or cannulation delay (vein palpability with tourniquet: model AUC: 0.60). Conclusion Our study shows that venous cannulation is well established among paramedics. It presents itself with similar difficulties across medical professions. Not the numerous specific circumstances of prehospital emergency care, but universal factors inherent to the task will influence the success at venous catheterization.

Anaesthesia and orphan disease: Bloom's syndrome.

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Comparison of Xenon with LED illuminant in difficult and inhalation injury airway scenario: A randomized crossover manikin study

Purpose: The purpose of this study was to compare the effectiveness of a Xenon halogen with a light‐emitting diode (LED) laryngoscope light handle in a difficult airway scenario, as well as in an inhalation injury airway scenario that combines a difficult airway and a limited view. Methods: We recruited forty‐two anesthetists into a randomized crossover trial. Each performed tracheal intubation (TI) with a Xenon halogen and a LED light handle in the two manikin scenarios. The primary endpoint was the “time to intubate”. Other endpoints were the “time to vocal cords”, the “time to ventilate”, the rate of successful intubation, the number of intubation attempts, the Cormack‐Lehane score, the number of optimization maneuvers, the number of audible dental click sounds indicating dental damage and subjective impressions. Results: In the difficult airway scenario, no significant differences in the recorded intubation times were observed. In the inhalation injury airway scenario, the intubation times were significantly shorter using the LED light handle. Regarding the subjective values, the LED illuminant enabled a significant better view and illumination of the oropharyngeal space and the vocal cords, in both manikin scenarios. Conclusion: The LED laryngoscope light handle did not affect the recorded intubation times in the simulated difficult airway scenario, but provided significant advantages in the inhalation injury airway scenario that combines a difficult airway with a limited view caused by a sooted pharynx. We therefore hypothesize, that the LED illuminant might be beneficial in the airway management of burn patients with severe inhalation injury.