François Bégin

Perturbation of the postural control system induced by muscular fatigue

In this experiment, we induced muscular fatigue of ankle plantar-flexors to examine how it deteriorates the regulation of bipedal quiet upright standing. Postural stability was assessed in conditions with and without vision over 60 s period to examine not only classical postural variables (time- and frequency-domain analyses), but also structural variables (stabilogram-diffusion analysis). Muscular fatigue was induced with repeated plantar-flexion of both legs. With muscular fatigue, subjects exhibited an increased postural sway (faster center of pressure (CP) velocity, and greater CP mean and median frequency) and a decreased long-term scaling exponent compared with the control conditions. The fatigue conditions, however, did not modify the range of oscillations and the variability of the postural oscillations around the mean position of CP. The effects of muscular fatigue were similar with eyes open and eyes closed. These results suggest that fatigue did induce some changes in the control mode of postural stability, but the detection/action capabilities of the sensorimotor system remained partly efficient when the ankle plantar-flexors were fatigued. Furthermore, the decreased long-term scaling exponent observed with fatigue suggests that the control of upright stance operates in a less stochastic and more antipersistent manner when fatigue is present (i.e. past and future behaviors were more negatively correlated and thus more tightly regulated). Altogether, the present results suggest that, compared with the no-fatigue conditions, fatigue places higher demands on the postural control system by increasing the frequency of actions needed to regulate the upright stance.

The effects of moderate fatigue on dynamic balance control and attentional demands

BackgroundDuring daily activities, the active control of balance often is a task per se (for example, when standing in a moving bus). Other constraints like fatigue can add to the complexity of this balance task. In the present experiment, we examined how moderate fatigue induced by fast walking on a treadmill challenged dynamic balance control. We also examined if the attentional demands for performing the balance task varied with fatigue.MethodsSubjects (n = 10) performed simultaneously a dynamic balance control task and a probe reaction time task (RT) (serving as an indicator of attentional demands) before and after three periods of moderate fatigue (fast walking on a treadmill). For the balance control task, the real-time displacement of the centre of pressure (CP) was provided on a monitor placed in front of the subject, at eye level. Subjects were asked to keep their CP within a target (moving box) moving upward and downward on the monitor. The tracking performance was measured (time spent outside the moving box) and the CP behavior analyzed (mean CP speed and mean frequency of the CP velocity).ResultsModerate fatigue led to an immediate decrement of the performance on the balance control task; increase of the percentage of time spent outside the box and increase of the mean CP speed. Across the three fatigue periods, subjects improved their tracking performance and reduced their mean CP speed. This was achieved by increasing their frequency of actions; mean frequency of the CP velocity were higher for the fatigue periods than for the no fatigue periods. Fatigue also induced an increase in the attentional demands suggesting that more cognitive resources had to be allocated to the balance task with than without fatigue.ConclusionFatigue induced by fast walking had an initial negative impact on the control of balance. Nonetheless, subjects were able to compensate the effect of the moderate fatigue by increasing the frequency of actions. This adaptation, however, required that a greater proportion of the cognitive resources be allocated to the active control of the balance task.

Rural Patient Access to Primary Percutaneous Coronary Intervention Centers is Improved by a Novel Integrated Telemedicine Prehospital System

BACKGROUND As per American Heart Association/American College of Cardiology guidelines, the delay between first medical contact and balloon inflation should not exceed 90 min for primary percutaneous coronary intervention (PCI). In North America, few prehospital systems have been developed to grant rural populations timely access to PCI. OBJECTIVES The objective of the present study was to evaluate the ability of an ST-segment elevation myocardial infarction (STEMI) system serving suburban and rural populations to achieve the recommended 90-min interval benchmark for PCI. METHODS A prehospital telemedicine program was implemented in a rural and suburban region of the Quebec province. Three patient groups with STEMI were created according to trajectory: 1) patients already en route to a PCI center, 2) patients initially directed to the nearest hospital who were subsequently diverted to a PCI center during transport, and 3) patients directed to the nearest hospital without transfer for PCI. Time intervals were compared across groups. RESULTS Of the 208 patients diagnosed with STEMI, 14.9% were already on their way to a hospital with PCI capabilities, 75.0% were rerouted to a PCI center, and 10.1% were directed to the nearest local hospital. All patients but one arrived at the PCI center within the 60-min prehospital care interval, considering an additional 30 min for balloon inflation at the PCI center. CONCLUSION This study demonstrated that a regionalized prehospital system for STEMI patients could achieve the recommended 90-min interval benchmark for PCI, while giving timely access to PCI to rural populations that would not otherwise have access to this treatment.

Differences in Access to Services in Rural Emergency Departments of Quebec and Ontario

Introduction Rural emergency departments (EDs) are important safety nets for the 20% of Canadians who live there. A serious problem in access to health care services in these regions has emerged. However, there are considerable geographic disparities in access to trauma center in Canada. The main objective of this project was to compare access to local 24/7 support services in rural EDs in Quebec and Ontario as well as distances to Levels 1 and 2 trauma centers. Materials and Methods Rural EDs were identified through the Canadian Healthcare Associations Guide to Canadian Healthcare Facilities. We selected hospitals with 24/7 ED physician coverage and hospitalization beds that were located in rural communities. There were 26 rural EDs in Quebec and 62 in Ontario meeting these criteria. Data were collected from ministries of health, local health authorities, and ED statistics. Fisher’s exact test, the t-test or Wilcoxon-Mann-Whitney test, were performed to compare rural EDs of Quebec and Ontario. Results All selected EDs of Quebec and Ontario agreed to participate in the study. The number of EDs visits was higher in Quebec than in Ontario (19 322 ± 6 275 vs 13 446 ± 8 056, p = 0.0013). There were no significant differences between Quebec and Ontario’s local population and small town population density. Quebec’s EDs have better access to advance imaging services such as CT scanner (77% vs 15%, p < .0001) and most the consultant support and ICU (92% vs 31%, p < .0001). Finally, more than 40% of rural EDs in Quebec and Ontario are more than 300 km away from Levels 1 and 2 trauma centers. Conclusions Considering that Canada has a Universal health care system, the discrepancies between Quebec and Ontario in access to support services are intriguing. A nationwide study is justified to address this issue.

Subcutaneous Fentanyl Administration: A Novel Approach for Pain Management in a Rural and Suburban Prehospital Setting

Abstract Objective: To determine the feasibility, safety, and effectiveness of the subcutaneous route of fentanyl administration by Basic Life Support–Emergency Medical Technicians (BLS-EMT) in a rural and suburban region, with the support of an online pain management medical control center. Methods: Retrospective study of patients who received subcutaneous fentanyl and were transported by BLS-EMT to the emergency department (ED) of an academic hospital between July 1, 2013 and January 1, 2014, inclusively. Fentanyl orders were obtained from emergency physicians via an online medical control (OLMC) center. Effectiveness was defined by changes in pain scores 15 minutes, 30 minutes, and 45+ minutes after initial fentanyl administration. Safety was evaluated by measuring vital signs, Ramsay sedation scores, and adverse events subsequent to fentanyl administration. Feasibility was defined as successful fentanyl administration by BLS-EMT. SPSS-20 was used for descriptive statistics, and independent t-tests and Mann-Whitney U tests were used to determine inter- and intra-group differences based on transport time. Results: Two hundred and eighty-eight patients (288; 14 to 93 years old) with pain scores ≥7 were eligible for the study. Of the 284 (98.6%) who successfully received subcutaneous fentanyl, 35 had missing records or data, and 249 (86.5%) were included in analyses. Average pain score pre-fentanyl was 8.9 ± 1.1. Patients <70 years old received a higher dose of fentanyl than those ≥70 years old (1.4 ± 0.3 vs, 0.8 ± 0.2 mcg/kg, p < 0.05). Pain scores decreased significantly post-fentanyl administration and the proportion of patients achieving pain relief increased significantly (p < 0.05) over the course of transport to ED (15 minutes, 30 minutes, 45+ minutes). Only 1.6% of patients experienced adverse events, including hypotension (n = 2; 0.8%), nausea (n = 1; 0.4%), and Ramsay level >3 (n = 1; 0.4%). Conclusion: Prehospital subcutaneous fentanyl administration by BLS-EMT with the support of an OLMC center is a safe and feasible approach to pain relief in prehospital settings, and is not associated with major adverse events. Effectiveness, subsequent to subcutaneous fentanyl administration is characterized by a decrease in pain over the course of transport to ED. Further studies are needed to compare the effectiveness of SC administration by EMS with other routes of administration and other analgesics.

Detection of STEMI Using Prehospital Serial 12-Lead Electrocardiograms

Abstract Objective: Repeated or serial 12-lead electrocardiograms (ECGs) in the prehospital setting may improve management of patients with subtle ST-segment elevation (STE) or with a ST-segment elevation myocardial infarction (STEMI) that evolves over time. However, there is a minimal amount of scientific evidence available to support the clinical utility of this method. Our objective was to evaluate the use of serial 12-lead ECGs to detect STEMI in patients during transport in a Canadian emergency medical services (EMS) jurisdiction. Methods: We performed a retrospective study of suspected STEMI patients transported by EMS in the Chaudière-Appalaches region (Québec, Canada) between August 2006 and December 2013. Patients were monitored by a serial 12-lead ECG system where an averaged ECG was transmitted every 2 minutes. Following review by an emergency physician, ECGs were grouped as having either a persistent STE or a dynamic STE that evolved over time. Results: A total of 754 suspected STEMI patients were transported by EMS during the study period. Of these, 728 patients met eligibility criteria and were included in the analysis. A persistent STE was observed in 84.3% (614/728) of patients, while the remaining 15.7% (114/728) had a dynamic STE. Among those with dynamic STE, 11.1% (81/728) had 1 ST-segment change (41 no-STEMI to STEMI; 40 STEMI to no-STEMI) and 4.5% (33/728) had ≥ 2 ST-segment changes (17 no-STEMI to STEMI; 16 STEMI to no-STEMI). Overall, in 8.0% (58/728) of the cohort, STEMI was identified on a subsequent ECG following an initial no-STEMI ECG. Conclusions: Through recognition of transient ST-segment changes during transport via the prehospital serial 12-lead ECG system, STEMI was identified in 8% of suspected STEMI patients who had an initial no-STEMI ECG. Key words: electrocardiography; emergency medical services; ST-elevation myocardial infarction; prehospital dynamic ECG

Clinical adverse events in prehospital patients with ST-elevation myocardial infarction transported to a percutaneous coronary intervention centre by basic life support paramedics in a rural region

OBJECTIVES It remains unclear whether ST-elevation myocardial infarction (STEMI) patients transported by ambulance over long distances are at risk for clinical adverse events. We sought to determine the frequency of clinical adverse events in a rural population of STEMI patients and to evaluate the impact of transport time on the occurrence of these events in the presence of basic life support paramedics. METHODS We performed a health records review of 880 consecutive STEMI patients transported to a percutaneous coronary intervention centre. Patients had continuous electrocardiogram and vital sign monitoring during transport. A classification of clinically important and minor adverse events was established based on a literature search and expert consensus. A multivariate ordinal logistic regression model was used to study the association between transport time (0-14, 15-29, ≥30 minutes) and the occurrence of overall clinical adverse events. RESULTS Clinically important and minor events were experienced by 18.5% and 12.2% of STEMI patients, respectively. The most frequent clinically important events observed were severe hypotension (6.1%) and ventricular tachycardia/ventricular fibrillation (5.1%). Transport time was not associated with a higher risk of experiencing clinical adverse events (p=0.19), but advanced age was associated with adverse events (p=0.03). No deaths were recorded during prehospital transport. CONCLUSIONS In our study of rural STEMI patients, clinical adverse events were common (30.7%). However, transport time was not associated with the occurrence of adverse clinical events in these patients.

Diagnostic accuracy of prehospital electrocardiograms interpreted remotely by emergency physicians in myocardial infarction patients

BACKGROUND Prehospital 12‑lead electrocardiogram (ECG) is the most widely used screening tool for recognition of ST-segment elevation myocardial infarction (STEMI). However, prehospital diagnosis of STEMI based solely on ECGs can be challenging. OBJECTIVES To evaluate the ability of emergency department (ED) physicians to accurately interpret prehospital 12‑lead ECGs from a remote location. METHODS All suspected prehospital STEMI patients who were transported by EMS and underwent angiography between 2006 and 2014 were included. We reviewed prehospital ECGs and grouped them based on: 1) presence or absence of a culprit artery lesion following angiography; and 2) whether they met the 3rd Universal Definition of Myocardial Infarction. We also described characteristics of ECGs that were misinterpreted by ED physicians. RESULTS A total of 625 suspected STEMI cases were reviewed. Following angiography, 94% (590/625) of patients were found having a culprit artery lesion, while 6% (35/625) did not. Among these 35 patients, 24 had ECGs that mimicked STEMI criteria and 9 had non-ischemic signs. Upon ECG reinterpretation, 92% (577/625) had standard STEMI criteria while 8% (48/625) did not. Among these 48 patients, 35 had ischemic signs ECGs and 13 did not. Characteristics of misinterpreted ECGs included pericarditis, early repolarization, STE > 1 mm (1‑lead only), and negative T-wave. CONCLUSIONS Remote interpretation of prehospital 12‑lead ECGs by ED physicians was a useful diagnostic tool in this EMS system. Even if the rate of ECG misinterpretation is low, there is still room for ED physicians operating from a remote location to improve their ability to accurately diagnose STEMI patients.