Virtual learning allows for adaptation of study strategies in a cohort of U.S. medical students.

BACKGROUND: In response to the COVID-19 pandemic, most U.S. medical schools acutely transitioned from regimented in-person learning to highly flexible virtual asynchronous learning. This transition at our medical school provided a unique opportunity to evaluate if and how students adapted their academic and personal lives in response. METHODS: Medical students in a single class that made this transition were retrospectively provided with 24-hour diaries for three periods - one shortly before the transition, a second early in the transition, and third several months into the transition - and asked to select the academic or personal activities done in each hour. The percentage of medical students performing each activity each hour was analyzed, as was the time spent on each activity per day, and per morning, afternoon, per evening within the day. RESULTS: Overall study time did not change in either virtual period but shifted significantly to the morning (6 AM to 12 PM). Time spent studying in groups fell significantly during both virtual periods, concordant with a significant increase in alone study time in the early virtual period. Early in the transition to virtual learning, students replaced in-person didactics with online faculty lectures; several months later in virtual learning, they had replaced online faculty lectures with commercial products. There was no significant change in time spent on specific personal activities. CONCLUSIONS: Consistent with extensive constraints imposed by the heavy cognitive load of a medical school curriculum, students did not significantly change their overall study time and any self-care-related activities in the transition to virtual learning. However, transitioning to virtual learning allowed our students to adapt their study strategies, i.e. reducing group study time and increasing lone studying time. Furthermore, students shifted studying time to the morning to optimize the management of the cognitive task-load they faced.

Acute Stroke: Current Evidence-based Recommendations for Prehospital Care.

INTRODUCTION: In the United States, emergency medical services (EMS) protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of a patient with a suspected stroke and to compare these recommendations against the current protocols used by the 33 EMS agencies in the state of California. METHODS: We performed a literature review of the current evidence in the prehospital treatment of a patient with a suspected stroke and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the stroke protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were the use of a stroke scale, blood glucose evaluation, use of supplemental oxygen, patient positioning, 12-lead electrocardiogram (ECG) and cardiac monitoring, fluid assessment and intravenous access, and stroke regionalization. RESULTS: Protocols across EMS agencies in California varied widely. Most used some sort of stroke scale with the majority using the Cincinnati Prehospital Stroke Scale (CPSS). All recommended the evaluation of blood glucose with the level for action ranging from 60 to 80 mg/dL. Cardiac monitoring was recommended in 58% and 33% recommended an ECG. More than half required the direct transport to a primary stroke center and 88% recommended hospital notification. CONCLUSION: Protocols for a patient with a suspected stroke vary widely across the state of California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

Feasibility and Safety of Using External Counterpulsation to Augment Cerebral Blood Flow in Acute Ischemic Stroke-The Counterpulsation to Upgrade Forward Flow in Stroke (CUFFS) Trial.

BACKGROUND: External counterpulsation (ECP) increases perfusion to a variety of organs and may be helpful for acute stroke. METHODS: We conducted a single-blinded, prospective, randomized controlled feasibility and safety trial of ECP for acute middle cerebral artery (MCA) ischemic stroke. Twenty-three patients presenting within 48 hours of symptom onset were randomized into one of two groups. One group was treated with ECP for 1 hour at a pressure of up to 300 mmHg ("full pressure"). During the procedure, we also determined the highest possible pressure that would augment MCA mean flow velocity (MFV) by 15%. The other group was treated with ECP at 75 mmHg ("sham pressure"). Transcranial Doppler MCA flow velocities and National Institutes of Health Stroke Scale (NIHSS) scores of both groups were checked before, during, and after ECP. Outcomes were assessed at 30 days after randomization. RESULTS: Although the procedures were feasible to implement, there was a frequent inability to augment MFV by 15% despite maximal pressures in full-pressure patients. In sham-pressure patients, however, MFV frequently increased as shown by increases in peak systolic velocity and end diastolic velocity. In both groups, starting ECP was often associated with contemporaneous improvements in NIHSS stroke scores. There were no between-group differences in NIHSS, modified Rankin Scale Scores, and Barthel Indices, and no device or treatment-related serious adverse events, deaths, intracerebral hemorrhages, or episodes of acute neuro-worsening. CONCLUSIONS: ECP was safe and feasible to use in patients with acute ischemic stroke. It was associated with unexpected effects on flow velocity, and contemporaneous improvements in NIHSS score regardless of pressure used, with a possibility that even very low ECP pressures had an effect. Further study is warranted.

Therapeutic hypothermia is associated with a decrease in urine output in acute stroke patients.

AIMS: It is unclear what effect therapeutic hypothermia may have on renal function, because its effect has so far been primarily evaluated in settings in which there may be possible confounding perturbations in cardiovascular and renal physiology, such deep intraoperative hypothermia, general anesthesia, and post-cardiac arrest. We sought to determine if therapeutic hypothermia affects renal function in awake patients with normal renal function who were enrolled into a clinical trial of hypothermia plus intravenous thrombolysis for acute ischemic stroke. METHODS: Eleven patients with normal renal function were cooled to 33°C for 24 h using an endovascular catheter, and then re-warmed over 12 h to 36.5°C, while hourly temperature, blood pressure, and fluid status data was recorded. Blood samples for blood urea nitrogen (BUN), creatinine, and hematocrit were drawn prior to treatment (baseline), immediately after hypothermia and re-warming (day 2), and again at day 7 or discharge, and values compared. RESULTS: On initiation of cooling, temperatures dropped from a median pre-treatment value of 36.1°C (IQR: 35.8-36.4°C) to 33.1°C (IQR: 33.1-33.4°C). Urine output decreased 5.1 ml/h for every 1°C decrease in body temperature (p-value=0.001), with no associated serious adverse events. There were no statistically significant changes in BUN, creatinine, or hematocrit in the hypothermia patients. CONCLUSION: Inducing hypothermia in patients with relatively unperturbed renal physiology results in a decrease in urine output that is linearly correlated with the decrease in core temperature. This has important implications for fluid management in patients undergoing therapeutic hypothermia.

Intravenous thrombolysis plus hypothermia for acute treatment of ischemic stroke (ICTuS-L): final results.

BACKGROUND AND PURPOSE: Induced hypothermia is a promising neuroprotective therapy. We studied the feasibility and safety of hypothermia and thrombolysis after acute ischemic stroke. METHODS: Intravenous Thrombolysis Plus Hypothermia for Acute Treatment of Ischemic Stroke (ICTuS-L) was a randomized, multicenter trial of hypothermia and intravenous tissue plasminogen activator in patients treated within 6 hours after ischemic stroke. Enrollment was stratified to the treatment time windows 0 to 3 and 3 to 6 hours. Patients presenting within 3 hours of symptom onset received standard dose intravenous alteplase and were randomized to undergo 24 hours of endovascular cooling to 33°C followed by 12 hours of controlled rewarming or normothermia treatment. Patients presenting between 3 and 6 hours were randomized twice: to receive tissue plasminogen activator or not and to receive hypothermia or not. Results- In total, 59 patients were enrolled. One patient was enrolled but not treated when pneumonia was discovered just before treatment. All 44 patients enrolled within 3 hours and 4 of 14 patients enrolled between 3 to 6 hours received tissue plasminogen activator. Overall, 28 patients randomized to receive hypothermia (HY) and 30 to normothermia (NT). Baseline demographics and risk factors were similar between groups. Mean age was 65.5±12.1 years and baseline National Institutes of Health Stroke Scale score was 14.0±5.0; 32 (55%) were male. Cooling was achieved in all patients except 2 in whom there were technical difficulties. The median time to target temperature after catheter placement was 67 minutes (Quartile 1 57.3 to Quartile 3 99.4). At 3 months, 18% of patients treated with hypothermia had a modified Rankin Scale score of 0 or 1 versus 24% in the normothermia groups (nonsignificant). Symptomatic intracranial hemorrhage occurred in 4 patients (68); all were treated with tissue plasminogen activator <3 hours (1 received hypothermia). Six patients in the hypothermia and 5 in the normothermia groups died within 90 days (nonsignificant). Pneumonia occurred in 14 patients in the hypothermia and in 3 of the normothermia groups (P=0.001). The pneumonia rate did not significantly adversely affect 3 month modified Rankin Scale score (P=0.32). CONCLUSIONS: This study demonstrates the feasibility and preliminary safety of combining endovascular hypothermia after stroke with intravenous thrombolysis. Pneumonia was more frequent after hypothermia, but further studies are needed to determine its effect on patient outcome and whether it can be prevented. A definitive efficacy trial is necessary to evaluate the efficacy of therapeutic hypothermia for acute stroke.

Comparison of the post-embolization effects of tissue-plasminogen activator and simvastatin on neurological outcome in a clinically relevant rat model of acute ischemic stroke.

Data has emerged, largely from non-thromboembolic animal models of stroke, that suggests that statins, which have efficacy in preventing strokes when given pre-ischemically, may have a positive effect on stroke even when given post-ischemically, possibly through pleitropic cerebrovascular effects. The goal of this study was to characterize the effects of IV tPA in a clinically relevant model of stroke utilizing a vascular occlusion with a freshly formed clot, and evaluate the effects of post-ischemic administration of simvastatin on stroke outcome in this model. Neurological deficit, clot burden, and lesion volume were assessed after treatment with tPA in one experiment, and after treatment with simvastatin in another. In the tPA experiment, treatment with 10mg/kg of tPA IV (with 20% given as an initial bolus, and 80% given as an infusion over the remaining 30 min), starting within an hour after stroke, resulted in significant reductions, compared with control animals, in neurological deficit (mean+/-SD neuroscores of 21.5+/-21.1 and 30+/-29.3, respectively, p=0.005), clot burden (p=0.010) and lesion volume (p=0.049) at 24h. In the simvastatin experiment on the other hand, treatment with a 20mg/kg of simvastatin as a single intraperitoneal dose within an hour after stroke resulted in no salutary effects on neurological deficit, clot burden or lesion volume compared with controls at 24h. These results suggest that more research needs to be done to fully ascertain the therapeutic potential and optimal dosing paradigm of a post-ischemic treatment with a statin.

Accuracy of stroke recognition by emergency medical dispatchers and paramedics--San Diego experience.

BACKGROUND: Prehospital personnel in Emergency Medical Service (EMS) systems have varying levels of accuracy in stroke recognition. Identifying the accuracy of emergency medical dispatcher using Medical Priority Dispatch Systems (MPDS) stroke protocol and paramedics may help understand the accuracy of stroke recognition in about 3000 emergency medical dispatch systems and prehospital systems world wide. OBJECTIVE: Our aim was to assess the accuracy of stroke identification in emergency medical dispatchers (EMD) with high compliance to MPDS protocol and paramedics using Cincinnati Prehospital Stroke Scale (CSS). METHODS: This was a retrospective observational study. Data was acquired from a computer assisted dispatch (CAD) system, a computerized paramedic record database and discharge diagnosis from billing records or stroke registry containing all stroke assessments of patients who presented to the participating study hospitals within 12 hours of symptom onset. We included patients 18 years or older, identified as having stroke by EMD and city agency paramedics. We excluded patients taken to hospitals not participating in the study, patients with a dispatch determinant of Stroke (card 28) not transported by City EMS agency (SDMSE) to participating hospitals, patients in the stroke registry not transported by SDMSE or patients with no final outcome data. A stroke neurologist or hospital discharge diagnosis of stroke (physician diagnosis) was used to determine the sensitivity and predictive values of EMD and paramedic recognition of stroke. RESULTS: Of 882 patients with a dispatch determinant of stroke using MPDS Stroke protocol, 367 had a final discharge diagnosis of stroke. This gives a sensitivity of 83% and a positive predictive value of 42% for EMD using MPDS Stroke protocol. Of 477 patients with a paramedic assessment of stroke using CSS, 193 had a final discharge diagnosis of stroke. This gives a sensitivity of 44% and a PPV of 40% for paramedics using CSS. CONCLUSIONS: In our EMS system, EMD using MPDS Stroke protocol with a high compliance has a higher sensitivity than paramedics using CSS.

Effect of endovascular hypothermia on acute ischemic edema: morphometric analysis of the ICTuS trial.

INTRODUCTION: Pilot studies of hypothermia for stroke suggest a potential benefit in humans. We sought to test whether hypothermia decreases post-ischemic edema using CT scans from a pilot trial of endovascular hypothermia for stroke. METHODS: Eighteen patients with acute ischemic stroke underwent therapeutic hypothermia (target = 33 degrees C) for 12 or 24 h followed by a 12-h controlled re-warm using an endovascular system. CT scans obtained at baseline, 36-48 h (right after cooling and re-warming) and 30 days were digitized, intracranial compartment volumes measured using a validated stereological technique, and the calculated change in CSF volume between the three time-points were used as an estimate of edema formation in each patient. Patients were grouped retrospectively for analysis based on whether they cooled effectively (i.e., to a temperature nadir of less than 34.5 degrees C within 8 h) or not. RESULTS: Eleven patients were cooled partially or not at all, and seven were effectively cooled. Baseline demographics and compartment volumes and densities were similar in both groups. At 36-48 h, the total CSF volume had significantly decreased in the not-cooled group compared to the cooled group (P < 0.05), with no significant difference in mean volume of ischemia between them (73 +/- 73 ml vs. 54 +/- 59 ml, respectively), suggesting an ameliorative effect of hypothermia on acute edema formation. At 30 days, the difference in CSF volumes had resolved, and infarct volumes (73 +/- 71 ml vs. 84 +/- 102 ml, respectively) and functional outcomes were comparable. CONCLUSIONS: Endovascular hypothermia decreases acute post-ischemic cerebral edema. A larger trial is warranted to determine if it affects final infarct volume and outcome in stroke.

A trial of therapeutic hypothermia via endovascular approach in awake patients with acute ischemic stroke: methodology.

BACKGROUND: Therapeutic hypothermia has been shown to be of benefit in improving neurological outcome in cardiac arrest. It now is being investigated in acute stroke and myocardial infarction. The majority of the literature describes its use in intubated, pharmacologically paralyzed patients, using surface cooling techniques that are susceptible to patient shivering, imprecise temperature control, time lag to target-temperature acquisition, and rebound hyperthermia. OBJECTIVES: To develop a method of inducing therapeutic hypothermia in a rapid, precise, and tolerable fashion in awake, nonintubated patients. METHODS: This method was developed for an ongoing clinical trial investigating a combination of therapeutic hypothermia and intravenous thrombolysis for acute ischemic stroke. In the protocol, an endovascular cooling device is placed in the inferior vena cava of a patient, and a combination of buspirone, meperidine, and cutaneous warming with a heating blanket is used to suppress shivering as the patient is cooled to a target temperature of 33 degrees C, kept there for a total of 24 hours from hypothermia initiation, and then rewarmed in a controlled fashion during the next 12 hours. RESULTS: Ten patients underwent the therapeutic hypothermia protocol. The median pretreatment core temperature was 36.1 degrees C (interquartile range [IQR]: 35.8 degrees C-36.4 degrees C). On initiation of cooling, the core temperatures dropped rapidly and then leveled off, approaching a median plateau value of 33.4 degrees C (IQR: 33.2 degrees C-33.9 degrees C) in a mean time of 1.7 (+/- 0.7) hours from cooling initiation, with a median average postplateau temperature during the cooling phase of 33.8 degrees C (IQR: 33.3 degrees C-34.6 degrees C), and a median lowest temperature of 33.1 degrees C (IQR: 33.0 degrees C-33.3 degrees C). The procedure was well tolerated, with minimal shivering and no rebound hyperthermia. CONCLUSIONS: This is a method by which a rapid and precise therapeutic decrease in core temperature can be achieved without the necessity for intubation or neuromuscular blockade and with minimal patient discomfort or shivering.