Effect of Daytime versus Nighttime on Prehospital Care and Outcomes after Severe Traumatic Brain Injury

Background/Objectives: Severe traumatic brain injury (TBI) is a frequent cause of morbidity and mortality worldwide. In the Netherlands, suspected TBI is a criterion for the dispatch of the physician-staffed helicopter emergency medical services (HEMS) which are operational 24 h per day. It is unknown if patient outcome is influenced by the time of day during which the incident occurs. Therefore, we investigated the association between the time of day of the prehospital treatment of severe TBI and 30-day mortality. Methods: A retrospective analysis of prospectively collected data from the BRAIN-PROTECT study was performed. Patients with severe TBI treated by one of the four Dutch helicopter emergency medical services were included and followed up to one year. The association between prehospital treatment during day- versus nighttime, according to the universal daylight period, and 30-day mortality was analyzed with multivariable logistic regression. A planned subgroup analysis was performed in patients with TBI with or without any other injury. Results: A total of 1794 patients were included in the analysis, of which 1142 (63.7%) were categorized as daytime and 652 (36.3%) as nighttime. Univariable analysis showed a lower 30-day mortality in patients with severe TBI treated during nighttime (OR 0.74, 95% CI 0.60-0.91, p = 0.004); this association was no longer present in the multivariable model (OR 0.82, 95% CI 0.59-1.16, p = 0.262). In a subgroup analysis, no association was found between mortality rates and the time of prehospital treatment in patients with combined injuries (TBI and any other injury). Patients with isolated TBI had a lower mortality rate when treated during nighttime than when treated during daytime (OR 0.51, 95% CI 0.34-0.76, p = 0.001). Within the whole cohort, daytime versus nighttime treatments were not associated with differences in functional outcome defined by the Glasgow Outcome Scale. Conclusions: In the overall study population, no difference was found in 30-day mortality between patients with severe TBI treated during day or night in the multivariable model. Patients with isolated severe TBI had lower mortality rates at 30 days when treated at nighttime.

Etomidate versus Ketamine as Prehospital Induction Agent in Patients with Suspected Severe Traumatic Brain Injury

BACKGROUND

Severe traumatic brain injury is a leading cause of morbidity and mortality among young people around the world. Prehospital care focuses on the prevention and treatment of secondary brain injury and commonly includes tracheal intubation after induction of general anesthesia. The choice of induction agent in this setting is controversial. This study therefore investigated the association between the chosen induction medication etomidate versus S(+)-ketamine and the 30-day mortality in patients with severe traumatic brain injury who received prehospital airway management in the Netherlands.

METHODS

This study is a retrospective analysis of the prospectively collected observational data of the Brain Injury: Prehospital Registry of Outcomes, Treatments and Epidemiology of Cerebral Trauma (BRAIN-PROTECT) cohort study. Patients with suspected severe traumatic brain injury who were transported to a participating trauma center and who received etomidate or S(+)-ketamine for prehospital induction of anesthesia for advanced airway management were included. Statistical analyses were performed with multivariable logistic regression and inverse probability of treatment weighting analysis.

RESULTS

In total, 1,457 patients were eligible for analysis. No significant association between the administered induction medication and 30-day mortality was observed in unadjusted analyses (32.9% mortality for etomidate versus 33.8% mortality for S(+)-ketamine; P = 0.716; odds ratio, 1.04; 95% CI, 0.83 to 1.32; P = 0.711), as well as after adjustment for potential confounders (odds ratio, 1.08; 95% CI, 0.67 to 1.73; P = 0.765; and risk difference 0.017; 95% CI, -0.051 to 0.084; P = 0.686). Likewise, in planned subgroup analyses for patients with confirmed traumatic brain injury and patients with isolated traumatic brain injury, no significant differences were found. Consistent results were found after multiple imputations of missing data.

CONCLUSIONS

The analysis found no evidence for an association between the use of etomidate or S(+)-ketamine as an anesthetic agent for intubation in patients with traumatic brain injury and mortality after 30 days in the prehospital setting, suggesting that the choice of induction agent may not influence the patient mortality rate in this population.

EDITOR’S PERSPECTIVE

Traumatic Cardiac Arrest-A Narrative Review

A paradigm shift in traumatic cardiac arrest (TCA) perception switched the traditional belief of futility of TCA resuscitation to a more optimistic perspective, at least in selected cases. The goal of TCA resuscitation is to rapidly and aggressively treat the common potentially reversible causes of TCA. Advances in diagnostics and therapy in TCA are ongoing; however, they are not always translating into improved outcomes. Further research is needed to improve outcome in this often young and previously healthy patient population.

Association between prehospital end-tidal carbon dioxide levels and mortality in patients with suspected severe traumatic brain injury

PURPOSE

Severe traumatic brain injury is a leading cause of mortality and morbidity, and these patients are frequently intubated in the prehospital setting. Cerebral perfusion and intracranial pressure are influenced by the arterial partial pressure of CO₂ and derangements might induce further brain damage. We investigated which lower and upper limits of prehospital end-tidal CO₂ levels are associated with increased mortality in patients with severe traumatic brain injury.

METHODS

The BRAIN-PROTECT study is an observational multicenter study. Patients with severe traumatic brain injury, treated by Dutch Helicopter Emergency Medical Services between February 2012 and December 2017, were included. Follow-up continued for 1 year after inclusion. End-tidal CO₂ levels were measured during prehospital care and their association with 30-day mortality was analyzed with multivariable logistic regression.

RESULTS

A total of 1776 patients were eligible for analysis. An L-shaped association between end-tidal CO₂ levels and 30-day mortality was observed (p = 0.01), with a sharp increase in mortality with values below 35 mmHg. End-tidal CO₂ values between 35 and 45 mmHg were associated with better survival rates compared to < 35 mmHg. No association between hypercapnia and mortality was observed. The odds ratio for the association between hypocapnia (< 35 mmHg) and mortality was 1.89 (95% CI 1.53-2.34, p < 0.001) and for hypercapnia (≥ 45 mmHg) 0.83 (0.62-1.11, p = 0.212).

CONCLUSION

A safe zone of 35-45 mmHg for end-tidal CO₂ guidance seems reasonable during prehospital care. Particularly, end-tidal partial pressures of less than 35 mmHg were associated with a significantly increased mortality.

Cognitive performance in multiple sclerosis: what is the role of the gamma-aminobutyric acid system?

Cognitive impairment occurs in 40-65% of persons with multiple sclerosis and may be related to alterations in glutamatergic and GABAergic neurotransmission. Therefore, the aim of this study was to determine how glutamatergic and GABAergic changes relate to cognitive functioning in multiple sclerosis in vivo. Sixty persons with multiple sclerosis (mean age 45.5 ± 9.6 years, 48 females, 51 relapsing-remitting multiple sclerosis) and 22 age-matched healthy controls (45.6 ± 22.0 years, 17 females) underwent neuropsychological testing and MRI. Persons with multiple sclerosis were classified as cognitively impaired when scoring at least 1.5 standard deviations below normative scores on ≥30% of tests. Glutamate and GABA concentrations were determined in the right hippocampus and bilateral thalamus using magnetic resonance spectroscopy. GABA-receptor density was assessed using quantitative [¹¹C]flumazenil positron emission tomography in a subset of participants. Positron emission tomography outcome measures were the influx rate constant (a measure predominantly reflecting perfusion) and volume of distribution, which is a measure of GABA-receptor density. Twenty persons with multiple sclerosis (33%) fulfilled the criteria for cognitive impairment. No differences were observed in glutamate or GABA concentrations between persons with multiple sclerosis and healthy controls, or between cognitively preserved, impaired and healthy control groups. Twenty-two persons with multiple sclerosis (12 cognitively preserved and 10 impaired) and 10 healthy controls successfully underwent [¹¹C]flumazenil positron emission tomography. Persons with multiple sclerosis showed a lower influx rate constant in the thalamus, indicating lower perfusion. For the volume of distribution, persons with multiple sclerosis showed higher values than controls in deep grey matter, reflecting increased GABA-receptor density. When comparing cognitively impaired and preserved patients to controls, the preserved group showed a significantly higher volume of distribution in cortical and deep grey matter and hippocampus. Positive correlations were observed between both positron emission tomography measures and information processing speed in the multiple sclerosis group only. Whereas concentrations of glutamate and GABA did not differ between multiple sclerosis and control nor between cognitively impaired, preserved and control groups, increased GABA-receptor density was observed in preserved persons with multiple sclerosis that was not seen in cognitively impaired patients. In addition, GABA-receptor density correlated to cognition, in particular with information processing speed. This could indicate that GABA-receptor density is upregulated in the cognitively preserved phase of multiple sclerosis as a means to regulate neurotransmission and potentially preserve cognitive functioning.

Prehospital Intubation of Patients with Severe Traumatic Brain Injury: A Dutch Nationwide Trauma Registry Analysis

ObjectivePatients with severe traumatic brain injury (TBI) are commonly intubated during prehospital treatment despite a lack of evidence that this is beneficial. Accumulating evidence even suggests that prehospital intubation may be hazardous, in particular when performed by inexperienced EMS clinicians. To expand the limited knowledge base, we studied the relationship between prehospital intubation and hospital mortality in patients with severe TBI in a large Dutch trauma database. We specifically hypothesized that the relationship differs depending on whether a physician-based emergency medical service (EMS) was involved in the treatment, as opposed to intubation by paramedics.MethodsA retrospective analysis was performed using the Dutch Nationwide Trauma Registry that includes all trauma patients in the Netherlands who are admitted to any hospital with an emergency department. All patients treated for severe TBI (Head Abbreviated Injury Scale score ≥4) between January 2015 and December 2019 were selected. Multivariable logistic regression was used to assess the relationship between prehospital intubation and mortality while adjusting for potential confounders. An interaction term between prehospital intubation and the involvement of physician-based EMS was added to the model. Complete case analysis as well as multiple imputation were performed.Results8946 patients (62% male, median age 63 years) were analyzed. The hospital mortality was 26.4%. Overall, a relationship between prehospital intubation and higher mortality was observed (complete case: OR 1.86, 95%CI 1.35-2.57, P < 0.001; multiple imputation: OR 1.92, 95%CI 1.56-2.36, P < 0.001). Adding the interaction revealed that the relationship of prehospital intubation may depend on whether physician-based EMS is involved in the treatment (complete case: P = 0.044; multiple imputation: P = 0.062). Physician-based EMS involvement attenuated but did not completely remove the detrimental association between prehospital intubation and mortality.ConclusionThe data do not support the common practice of prehospital intubation. The effect of prehospital intubation on mortality might depend on EMS clinician experience, and it seems prudent to involve prehospital personnel well proficient in prehospital intubation whenever intubation is potentially required. The decision to perform prehospital intubation should not merely be based on the largely unsupported dogma that it is generally needed in severe TBI, but should rather individually weigh potential benefits and harms.

Monitoring and Management of Fibrodysplasia Ossificans Progressiva: Current Perspectives

Fibrodysplasia ossificans progressiva (FOP), sometimes known as myositis ossificans progressiva, is an ultra-rare disease in which bone is formed in muscular tissue, tendons and ligaments. This is known as heterotopic ossification (HO). FOP is caused by a heterozygous mutation in the highly conserved ACVR1/ALK2 gene which affects about 1 in 1.5–2 million individuals. At birth, patients with the predominant R206H mutation only exhibit a bilateral hallux valgus. During childhood, heterotopic bone formation develops in a typical pattern, affecting the axial muscles first before appendicular body parts are involved. HO can start spontaneously but is often elicited by soft tissue trauma or medical procedures. After soft tissue injury, an inflammatory process called a flare-up can start, followed by the formation of HO. HO leads to a limited range of motion, culminating in complete ankylosis of nearly all joints. As a result of HO surrounding the thorax, patients often suffer from thoracic insufficiency syndrome (TIS). TIS is the most common cause of a limited life expectancy for FOP patients, with a median life expectancy of 56 years. Management is focused on preventing soft-tissue injury that can provoke flare-ups. This includes prevention of iatrogenic damage by biopsies, intramuscular injections and surgery. Anti-inflammatory medication is often started when a flare-up occurs but has a poor basis of evidence. Several forms of potential treatment for FOP are being researched in clinical trials. Progression of the disease is monitored using CT and 18F-NaF PET/CT combined with functional assessments. Patients are regularly evaluated for frequently occurring complications such as restrictive lung disease. Here, we review the current management, monitoring and treatment of FOP.

Relationship between Biodistribution and Tracer Kinetics of 11C-Erlotinib, 18F-Afatinib and 11C-Osimertinib and Image Quality Evaluation Using Pharmacokinetic/Pharmacodynamic Analysis in Advanced Stage Non-Small Cell Lung Cancer Patients

Background: Patients with non-small cell lung cancer (NSCLC) driven by activating epidermal growth factor receptor (EGFR) mutations are best treated with therapies targeting EGFR, i.e., tyrosine kinase inhibitors (TKI). Radiolabeled EGFR-TKI and PET have been investigated to study EGFR-TKI kinetics and its potential role as biomarker of response in NSCLC patients with EGFR mutations (EGFRm). In this study we aimed to compare the biodistribution and kinetics of three different EGFR-TKI, i.e., 11C-erlotinib, 18F-afatinib and 11C-osimertinib. Methods: Data of three prospective studies and 1 ongoing study were re-analysed; data from thirteen patients (EGFRm) were included for 11C-erlotinib, seven patients for 18F-afatinib (EGFRm and EGFR wild type) and four patients for 11C-osimertinib (EGFRm). From dynamic and static scans, SUV and tumor-to-blood (TBR) values were derived for tumor, lung, spleen, liver, vertebra and, if possible, brain tissue. AUC values were calculated using dynamic time-activity-curves. Parent fraction, plasma-to-blood ratio and SUV values were derived from arterial blood data. Tumor-to-lung contrast was calculated, as well as (background) noise to assess image quality. Results: 11C-osimertinib showed the highest SUV and TBR (AUC) values in nearly all tissues. Spleen uptake was notably high for 11C-osimertinib and to a lesser extent for 18F-afatinib. For EGFRm, 11C-erlotinib and 18F-afatinib demonstrated the highest tumor-to-lung contrast, compared to an inverse contrast observed for 11C-osimertinib. Tumor-to-lung contrast and spleen uptake of the three TKI ranked accordingly to the expected lysosomal sequestration. Conclusion: Comparison of biodistribution and tracer kinetics showed that 11C-erlotinib and 18F-afatinib demonstrated the highest tumor-to-background contrast in EGFRm positive tumors. Image quality, based on contrast and noise analysis, was superior for 11C-erlotinib and 18F-afatinib (EGFRm) scans compared to 11C-osimertinib and 18F-afatinib (EGFR wild type) scans.

11C-Sorafenib and 15O-H2O PET for Early Evaluation of Sorafenib Therapy

Sorafenib leads to clinical benefit in a subgroup of patients, whereas all are exposed to potential toxicity. Currently, no predictive biomarkers are available. The purpose of this study was to evaluate whether ¹¹C-sorafenib and ¹⁵O-H₂O PET have potential to predict treatment efficacy. Methods: In this prospective exploratory study, 8 patients with advanced solid malignancies and an indication for sorafenib treatment were included. Microdose ¹¹C-sorafenib and perfusion ¹⁵O-H₂O dynamic PET scans were performed before and after 2 wk of sorafenib therapy. The main objective was to assess whether tumor ¹¹C-sorafenib uptake predicts sorafenib concentrations during therapy in corresponding tumor biopsy samples measured with liquid chromatography tandem mass spectrometry. Secondary objectives included determining the association of ¹¹C-sorafenib PET findings, perfusion ¹⁵O-H₂O PET findings, and sorafenib concentrations after therapeutic dosing with response. Results: ¹¹C-sorafenib PET findings did not predict sorafenib concentrations in tumor biopsy samples during therapy. In addition, sorafenib plasma and tumor concentrations were not associated with clinical outcome in this exploratory study. Higher ¹¹C-sorafenib accumulation in tumors at baseline and day 14 of treatment showed an association with poorer prognosis and correlated with tumor perfusion (Spearman correlation coefficient = 0.671, P = 0.020). Interestingly, a decrease in tumor perfusion measured with ¹⁵O-H₂O PET after only 14 d of therapy showed an association with response, with a decrease in tumor perfusion of 56% ± 23% (mean ± SD) versus 18% ± 32% in patients with stable and progressive disease, respectively. Conclusion: Microdose ¹¹C-sorafenib PET did not predict intratumoral sorafenib concentrations after therapeutic dosing, but the association between a decrease in tumor perfusion and clinical benefit warrants further investigation.

Face-to-Face Versus Telephonic Extended Glasgow Outcome Score Testing After Traumatic Brain Injury

OBJECTIVE

The Extended Glasgow Outcome Scale (GOS-E) is used for objective assessment of functional outcome in traumatic brain injury (TBI). In situations where face-to-face contact is not feasible, telephonic assessment of the GOS-E might be desirable. The aim of this study is to assess the level of agreement between face-to-face and telephonic assessment of the GOS-E.

SETTING

Multicenter study in 2 Dutch University Medical Centers. Inclusion was performed in the outpatient clinic (face-to-face assessment, by experienced neurologist), followed by assessment via telephone of the GOS-E after ±2 weeks (by trained researcher).

PARTICIPANTS

Patients ±6 months after TBI.

DESIGN

Prospective validation study.

MAIN MEASURES

Interrater agreement of the GOS-E was assessed with Cohen's weighted κ.

RESULTS

From May 2014 until March 2018, 50 patients were enrolled; 54% were male (mean age 49.1 years). Median time between trauma and in-person GOS-E examination was 158 days and median time between face-to-face and telephonic GOS-E was 15 days. The quadratic weighted κ was 0.79. Sensitivity analysis revealed a quadratic weighted κ of 0.77, 0.78, and 0.70 for moderate-severe, complicated mild, and uncomplicated mild TBI, respectively.

CONCLUSION

No disagreements of more than 1 point on the GOS-E were observed, with the κ value representing good or substantial agreement. Assessment of the GOS-E via telephone is a valid alternative to the face-to-face interview when in-person contact is not feasible.

Identifying advanced stage NSCLC patients who benefit from afatinib therapy using 18F-afatinib PET/CT imaging

OBJECTIVES

Non-small cell lung cancer (NSCLC) tumors harboring common (exon19del, L858R) and uncommon (e.g. G719X, L861Q) activating epidermal growth factor receptor (EGFR) mutations are best treated with EGFR tyrosine kinase inhibitors (TKI) such as the first-generation EGFR TKI erlotinib, second-generation afatinib or third-generation osimertinib. However, identifying these patients through biopsy is not always possible. Therefore, our aim was to evaluate whether ¹⁸F-afatinib PET/CT could identify patients with common and uncommon EGFR mutations. Furthermore, we evaluated the relation between tumor ¹⁸F-afatinib uptake and response to afatinib therapy.

MATERIALS AND METHODS

¹⁸F-afatinib PET/CT was performed in 12 patients: 6 EGFR wild type (WT), 3 EGFR common and 3 EGFR uncommon mutations. Tumor uptake of ¹⁸F-afatinib was quantified using TBR_WB_60-90 (tumor-to-whole blood activity ratio 60-90 min post-injection) for each tumor. Response was quantified per lesion using percentage of change (PC): [(response measurement (RM)-baseline measurement (BM))/BM]×100. Statistical analyses were performed using t-tests, correlation plots and sensitivity/specificity analysis.

RESULTS

Twenty-one tumors were identified. Injected dose was 348 ± 31 MBq. Group differences were significant between WT versus EGFR (common and uncommon) activating mutations (p = 0.03). There was no significant difference between EGFR common versus uncommon mutations (p = 0.94). A TBR_WB_60-90 cut-off value of 6 showed the best relationship with response with a sensitivity of 70 %, a specificity of 100 % and a positive predictive value of 100 %.

CONCLUSION

¹⁸F-afatinib uptake was higher in tumors with EGFR mutations (common and uncommon) compared to WT. Furthermore, a TBR_WB_60-90 cut-off of 6 was found to best predict response to therapy. ¹⁸F-afatinib PET/CT could provide a means to identify EGFR mutation positive patients who benefit from afatinib therapy.

Prehospital coagulation measurement by a portable blood analyzer in a helicopter emergency medical service (HEMS)

In helicopter emergency medical services, HEMS, coagulopathy presents both in trauma (e.g. consumption of coagulation factors) and non-trauma cases (e.g. anticoagulant use). Therefore, in HEMS coagulation measurements appear promising and Prothrombin Time (PT) and derived INR are attractive variables herein. We tested the feasibility of prehospital PT/INR coagulation measurements in HEMS. This study was performed at the Dutch HEMS, using a portable blood analyzer (i-Stat®1, Abbott). PT/INR measurements were performed on (hemodiluted) author's blood, and both trauma- and non-trauma HEMS patients. Device-related benefits of the i-Stat PT/INR system were portability, speed and ease of handling. Limitations included a rather narrow operational temperature range (16-30 °C). PT/INR measurements (n = 15) were performed on hemodiluted blood, and both trauma and non-trauma patients. The PT/INR results confirmed effects of hemodilution and anticoagulation, however, most measurement results were in the normal INR-range (0.9-1.2). We conclude that prehospital PT/INR measurements, although with limitations, are feasible in HEMS operations.

Characteristics of helicopter emergency medical services (HEMS) dispatch cancellations during a six-year period in a Dutch HEMS region

Background

For decades, Helicopter Emergency Medical Services (HEMS) contribute greatly to prehospital patient care by performing advanced medical interventions on-scene. Unnecessary dispatches, resulting in cancellations, cause these vital resources to be temporarily unavailable and generate additional costs. A previous study showed a cancellation rate of 43.5% in our trauma region. However, little recent data about cancellation rates and reasons exist, despite revision of dispatch protocols. This study examines the current cancellation rate in our trauma region over a six-year period. Additionally, cancellation reasons are evaluated per type of dispatch and initial incident report, upon which HEMS is dispatched.

Methods

This retrospective study analyzed the data of the Dutch HEMS Lifeliner 1 (North-West region of the Netherlands, covering a population of 5 million inhabitants), analyzing all subsequent cases between April 1st 2013 and April 1st 2019. Patient characteristics, type of dispatch (primary; based on dispatcher criteria versus secondary, as judged by the first ambulance team on site), initial incident report received by the EMS dispatch center, and information regarding day- or nighttime dispatches were collected. In case of cancellation, cancel rate and reason per type of dispatch and initial incident report were assessed.

Results

In total, 18,638 dispatches were included. HEMS was canceled in 54.5% (95% CI 53.8–55.3%) of cases. The majority of canceled dispatches (76.1%) were canceled because respiratory, hemodynamic, and neurologic parameters were stable. Dispatches simultaneously activated with EMS (primary dispatch) were canceled in 58.3%, compared to 15.1% when HEMS assistance was requested by EMS based on their findings on-scene (secondary dispatch). A cancellation rate of 54.6% was found in trauma related dispatches (n = 12,148), compared to 52.2% in non-trauma related dispatches (n = 5378). Higher cancellation rates exceeding 60% were observed in the less common dispatch categories, e.g., anaphylaxis (66.3%), unknown incident report (66.0%), assault with a blunt object (64.1%), obstetrics (62.8%), and submersion (61.9%).

Conclusion

HEMS cancellations are increased, compared to previous research in our region. Yet, the cancellations are acceptable as the effect on HEMS’ unavailbility remains minimized. Focus should be on identifying the patient in need of HEMS care while maintaining overtriage rates low. Continuous evaluation of HEMS triage is important, and dispatch criteria should be adjusted if necessary.

Identifying advanced stage NSCLC patients who benefit from afatinib therapy using 18F-afatinib PET/CT imaging

OBJECTIVES

Non-small cell lung cancer (NSCLC) tumors harboring common (exon19del, L858R) and uncommon (e.g. G719X, L861Q) activating epidermal growth factor receptor (EGFR) mutations are best treated with EGFR tyrosine kinase inhibitors (TKI) such as the first-generation EGFR TKI erlotinib, second-generation afatinib or third-generation osimertinib. However, identifying these patients through biopsy is not always possible. Therefore, our aim was to evaluate whether ¹⁸F-afatinib PET/CT could identify patients with common and uncommon EGFR mutations. Furthermore, we evaluated the relation between tumor ¹⁸F-afatinib uptake and response to afatinib therapy.

MATERIALS AND METHODS

¹⁸F-afatinib PET/CT was performed in 12 patients: 6 EGFR wild type (WT), 3 EGFR common and 3 EGFR uncommon mutations. Tumor uptake of ¹⁸F-afatinib was quantified using TBR_WB_60-90 (tumor-to-whole blood activity ratio 60-90 min post-injection) for each tumor. Response was quantified per lesion using percentage of change (PC): [(response measurement (RM)-baseline measurement (BM))/BM]×100. Statistical analyses were performed using t-tests, correlation plots and sensitivity/specificity analysis.

RESULTS

Twenty-one tumors were identified. Injected dose was 348 ± 31 MBq. Group differences were significant between WT versus EGFR (common and uncommon) activating mutations (p = 0.03). There was no significant difference between EGFR common versus uncommon mutations (p = 0.94). A TBR_WB_60-90 cut-off value of 6 showed the best relationship with response with a sensitivity of 70 %, a specificity of 100 % and a positive predictive value of 100 %.

CONCLUSION

¹⁸F-afatinib uptake was higher in tumors with EGFR mutations (common and uncommon) compared to WT. Furthermore, a TBR_WB_60-90 cut-off of 6 was found to best predict response to therapy. ¹⁸F-afatinib PET/CT could provide a means to identify EGFR mutation positive patients who benefit from afatinib therapy.

Comparison of videolaryngoscopy alone with video-assisted fibreoptic intubation in a difficult cadaver airway model

ABSTRACT

No Abstract.

Association Between Prehospital Tranexamic Acid Administration and Outcomes of Severe Traumatic Brain Injury

Importance

The development and expansion of intracranial hematoma are associated with adverse outcomes. Use of tranexamic acid might limit intracranial hematoma formation, but its association with outcomes of severe traumatic brain injury (TBI) is unclear.

Objective

To assess whether prehospital administration of tranexamic acid is associated with mortality and functional outcomes in a group of patients with severe TBI.

Design, Setting, and Participants

This multicenter cohort study is an analysis of prospectively collected observational data from the Brain Injury: Prehospital Registry of Outcome, Treatments and Epidemiology of Cerebral Trauma (BRAIN-PROTECT) study in the Netherlands. Patients treated for suspected severe TBI by the Dutch Helicopter Emergency Medical Services between February 2012 and December 2017 were included. Patients were followed up for 1 year after inclusion. Data were analyzed from January 10, 2020, to September 10, 2020.

Exposures

Administration of tranexamic acid during prehospital treatment.

Main Outcomes and Measures

The primary outcome was 30-day mortality. Secondary outcomes included mortality at 1 year, functional neurological recovery at discharge (measured by Glasgow Outcome Scale), and length of hospital stay. Data were also collected on demographic factors, preinjury medical condition, injury characteristics, operational characteristics, and prehospital vital parameters.

Results

A total of 1827 patients were analyzed, of whom 1283 (70%) were male individuals and the median (interquartile range) age was 45 (23-65) years. In the unadjusted analysis, higher 30-day mortality was observed in patients who received prehospital tranexamic acid (odds ratio [OR], 1.34; 95% CI, 1.16-1.55; P < .001), compared with patients who did not receive prehospital tranexamic acid. After adjustment for confounders, no association between prehospital administration of tranexamic acid and mortality was found across the entire cohort of patients. However, a substantial increase in the odds of 30-day mortality persisted in patients with severe isolated TBI who received prehospital tranexamic acid (OR, 4.49; 95% CI, 1.57-12.87; P = .005) and after multiple imputations (OR, 2.05; 95% CI, 1.22-3.45; P = .007).

Conclusions and Relevance

This study found that prehospital tranexamic acid administration was associated with increased mortality in patients with isolated severe TBI, suggesting the judicious use of the drug when no evidence for extracranial hemorrhage is present.

Thinking Out-of-the-Box: A Non-Standard Application of Standard Pulse-Oximetry and Standard Near-Infrared Spectroscopy in a COVID-19 Patient

PURPOSE

Purpose of this report is to describe the feasibility of lingual pulse oximetry and lingual near-infrared spectroscopy (NIRS) in a COVID-19 patient to assess lingual tissue viability after several days of mechanical ventilation in the prone position.

MATERIALS & METHODS

In a COVID-19 ICU-patient, the tongue became grotesquely swollen, hardened and protruding from the oral cavity after 20 h of mechanical ventilation uninterrupted in the prone position. To assess the doubtful viability of the tongue, pulse-oximetric hemoglobin O2-saturation (SpO2; Nellcor, OxiMax MAX-NI, Covidien, MA, USA) and NIRS-based, regional tissue O2-saturation measurements (rSO2; SenSmart, Nonin, MN, USA) were performed at the tongue.

RESULTS

At the tongue, regular pulse-oximetric waveforms with a pulse-oximetric hemoglobin O2-saturation (SpO2) of 88% were recorded, i.e. only slightly lower than the SpO2 reading at the extremities at that time (90%). Lingual NIRS-based rSO2 measurements yielded stable tissue rSO2-values of 76-78%, i.e. values expected also in other adequately perfused and oxygenated (muscle-) tissues.

CONCLUSION

Despite the alarming, clinical finding of a grotesquely swollen, rubber-hard tongue and clinical concerns on the adequacy of the tongue perfusion and oxygenation, our measurements of both arterial pulsatility (SpO2) and NIRS-based tissue oxygenation (rSO2) suggested adequate perfusion and oxygenation of the tongue, rendering non-vitality of the tongue, e.g. by lingual venous thrombosis, unlikely. To our knowledge, this is the first clinical report of lingual rSO2 measurement.

Operational experience of the Dutch helicopter emergency medical services (HEMS) during the initial phase of the COVID-19 pandemic: jeopardy on the prehospital care system?

Purpose

The SARS-CoV-2 virus has disrupted global and local medical supply chains. To combat the spread of the virus and prevent an uncontrolled outbreak with limited resources, national lockdown protocols have taken effect in the Netherlands since March 13^th, 2020. The aim of this study was to describe the incidence, type and characteristics of HEMS and HEMS-ambulance ‘Lifeliner 1’ dispatches during the initial phase of the COVID-19 pandemic compared to the same period one year prior.

Methods

A retrospective review of all HEMS and HEMS-ambulance ‘Lifeliner 1’ dispatches was performed from the start of Dutch nationwide lockdown orders from March 13th until May 13th, 2020 and the corresponding period one year prior. Dispatch-, operational-, patient-, injury-, and on-site treatment characteristics were extracted for analysis. In addition, the rate of COVID-19 positively tested HEMS personnel and the time physicians were unable to take call was described.

Results

During the initial phase of the COVID-19 pandemic, the HEMS and HEMS-ambulance was requested in 528 cases. One year prior, a total of 620 requests were received. The HEMS (helicopter and ambulance) was cancelled after deployment in 56.4% of the COVID-19 cohort and 50.7% of the historical cohort (P = 0.05). Incident location type did not differ between the two cohorts, specifically, there was no significant difference in the number of injuries that occurred at home in pandemic versus non-pandemic circumstances. Besides a decrease in the number of falls, the distribution of mechanisms of injury remained similar during the COVID-19 study period. There was no difference in self-inflicted injuries observed. Prehospital interventions remained similar during the COVID-19 pandemic compared to one year prior. Specifically, prehospital intubation did not differ between the two cohorts. The rate of COVID-19 positively tested HEMS personnel was 23.1%. Physicians who tested positive were unable to take call for a mean of 25 days (range 8–53).

Conclusion

A decrease in the number of deployments and increase in the number of cancelled missions was observed during the COVID-19 study period. No major differences in operational- and injury characteristics were found for HEMS and HEMS-ambulance dispatches between the initial phase of the COVID-19 pandemic in the Netherlands and the same period one year prior. These findings highlight the importance of continued operability of the HEMS, even during pandemic circumstances.

Level of evidence

III, retrospective comparative study.

Epidemiology, Prehospital Characteristics and Outcomes of Severe Traumatic Brain Injury in The Netherlands: The BRAIN-PROTECT Study

OBJECTIVE

A thorough understanding of the epidemiology, patient characteristics, trauma mechanisms, and current outcomes among patients with severe traumatic brain injury (TBI) is important as it may inform potential strategies to improve prehospital emergency care. The aim of this study is to describe the prehospital epidemiology, characteristics and outcome of (suspected) severe TBI in the Netherlands.

METHODS

The BRAIN-PROTECT study is a prospective observational study on prehospital management of patients with severe TBI in the Netherlands. The study population comprised all consecutive patients with clinical suspicion of TBI and a prehospital GCS score ≤ 8, who were managed by one of the 4 Helicopter Emergency Medical Services (HEMS). Patients were followed-up in 9 trauma centers until 1 year after injury. Planned sub-analyses were performed for patients with "confirmed" and "isolated" TBI.

RESULTS

Data from 2,589 patients, of whom 2,117 (81.8%) were transferred to a participating trauma center, were analyzed. The incidence rate of prehospitally suspected and confirmed severe TBI were 3.2 (95% CI: 3.1;3.4) and 2.7 (95% CI: 2.5;2.8) per 100,000 inhabitants per year, respectively. Median patient age was 46 years, 58.4% were involved in traffic crashes, of which 37.4% were bicycle related. 47.6% presented with an initial GCS of 3. The median time from HEMS dispatch to hospital arrival was 54 minutes. The overall 30-day mortality was 39.0% (95% CI: 36.8;41.2).

CONCLUSION

This article summarizes the prehospital epidemiology, characteristics and outcome of severe TBI in the Netherlands, and highlights areas in which primary prevention and prehospital care can be improved.

Prehospital fluid administration in patients with severe traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

Prehospital management of severe traumatic brain injury (TBI) focuses on preventing secondary brain injury. Therefore, hypotension should be prevented, or if present, should be promptly treated in order to maintain optimal cerebral perfusion pressure. Fluid resuscitation is a traditional mainstay in the prehospital treatment of hypotension, however, the choice of fluid type that is to be administered in the prehospital setting is the subject of an on-going debate. This systematic review and meta-analysis was therefore performed to assess the effect of different fluid types on outcome in patients with severe TBI.

METHODS

PubMed, Embase and Web of Science were searched for articles up to March 2020. Studies comparing two or more prehospital administered fluid types with suspected or confirmed severe TBI were deemed eligible for inclusion. Studied outcomes were mortality and (extended) Glasgow Outcome Scale (GOS). The meta-analysis tested for differences in survival between hypertonic saline (HTS) and normotonic crystalloids (i.e. normal saline or Lactated Ringer's) and between hypertonic saline with dextran (HSD) and normotonic crystalloids. The systematic review is registered in the PROSPERO register with number CRD42020140423.

RESULTS

This literature search yielded a total of 519 articles, of which 12 were included in the systematic review and 6 were included in the meta-analysis. Eleven studies found no statistically significant difference in survival between patients treated with different fluid types (e.g. normal saline and hypertonic saline). All studies assessing neurological outcome, measured through (extended) GOS, found no statistically significant difference between different fluid types. Meta-analysis showed no better survival for patients treated with HSD, when compared to normotonic crystalloids (overall RR 0.99, 95% CI 0.93-1.06). Moreover, HTS compared to normotonic crystalloids does not result in a better survival (overall RR 1.04, 95% CI 0.97-1.12).

CONCLUSIONS

This systematic review and meta-analysis did not demonstrate a survival or neurological benefit for one specific fluid type administered in the prehospital setting.

Suitability and realism of the novel Fix for Life cadaver model for videolaryngoscopy and fibreoptic tracheoscopy in airway management training

Background

Videolaryngoscopy is increasingly advocated as the standard intubation technique, while fibreoptic intubation is broadly regarded as the ‘gold standard’ for difficult airways. Traditionally, the training of these techniques is on patients, though manikins, simulators and cadavers are also used, with their respective limitations. In this study, we investigated whether the novel ‘Fix for Life’ (F4L) cadaver model is a suitable and realistic model for the teaching of these two intubation techniques to novices in airway management.

Methods

Forty consultant anaesthetists and senior trainees were instructed to perform tracheal intubation with videolaryngoscopy and fibreoptic tracheoscopy in four F4L cadaver models. The primary outcome measure was the verbal rating scores (scale 1–10, higher scores indicate a better rating) for suitability and for realism of the F4L cadavers as training model for these techniques. Secondary outcomes included success rates of the procedures and the time to successful completion of the procedures.

Results

The mean verbal rating scores for suitability and realism for videolaryngoscopy was 8.3 (95% CI, 7.9–8.6) and 7.2 (95% CI, 6.7–7.6), respectively. For fibreoptic tracheoscopy, suitability was 8.2 (95% CI, 7.9–8.5) and realism 7.5 (95% CI, 7.1–7.8). In videolaryngoscopy, 100% of the procedures were successful. The mean (SD) time until successful tracheal intubation was 34.8 (30.9) s. For fibreoptic tracheoscopy, the success rate was 96.3%, with a mean time of 89.4 (80.1) s.

Conclusions

We conclude that the F4L cadaver model is a suitable and realistic model to train and teach tracheal intubation with videolaryngoscopy and fibreoptic tracheoscopy to novices in airway management training.

First, do no harm: bilateral radial artery occlusion in a COVID-19 patient

Objective

Objective of this case report is to draw attention to a less known thrombotic complication associated with COVID-19, i.e., thrombosis of both radial arteries, with possible (long-term) consequences.

The Case

In our COVID-19 ICU a 49-year-old male patient was admitted, with past medical history of obesity, smoking and diabetes, but no reported atherosclerotic complications. The patient had been admitted with severe hypoxemia and multiple pulmonary emboli were CT-confirmed. ICU-treatment included mechanical ventilation and therapeutic anticoagulation. Preparing the insertion of a new radial artery catheter for invasive blood pressure measurement and blood sampling, we detected that both radial arteries were non-pulsating and occluded: (a) Sonography showed the typical anatomical localization of both radial and ulnar arteries. However, Doppler-derived flow-signals could only be obtained from the ulnar arteries. (b) To test collateral arterial supply of the hand, a pulse-oximeter was placed on the index finger. Thereafter, the ulnar artery at the wrist was compressed. This compression caused an immediate loss of the finger’s pulse-oximetry perfusion signal. The effect was reversible upon release of the ulnar artery. (c) To test for collateral perfusion undetectable by pulse-oximetry, we measured regional oxygen saturation (rSO₂) of the thenar muscle by near-infrared spectroscopy (NIRS). Confirming our findings above, ulnar arterial compression demonstrated that thenar rSO₂ was dependent on ulnar artery flow. The described development of bilateral radial artery occlusion in a relatively young and therapeutically anticoagulated patient with no history of atherosclerosis was unexpected.

Conclusions

Since COVID-19 patients are at increased risk for arterial occlusion, it appears advisable to meticulously check for adequacy of collateral (hand-) perfusion, avoiding the harm of hand ischemia if interventions (e.g., catheterizations) at the radial or ulnar artery are intended.

Pre-hospital transfusion of red blood cells. Part 1: A scoping review of current practice and transfusion triggers

OBJECTIVES

The primary aim of this scoping review is to describe the current use of pre-hospital transfusion of red blood cells (PHTRBC) and to evaluate criteria used to initiate PHTRBC. The effects on patients' outcomes will be reviewed in Part 2.

BACKGROUND

Haemorrhage is a preventable cause of death in trauma patients, and transfusion of red blood cells is increasingly used by Emergency Medical Services (EMS) for damage control resuscitation. However, there are no guidelines and little consensus on when to initiate PHTRBC.

METHODS

PubMed and Web of Science were searched through January 2019; 71 articles were included.

RESULTS

Transfusion triggers vary widely and involve vital signs, clinical signs of poor tissue perfusion, point of care measurements and pre-hospital ultrasound imaging. In particular, hypotension (most often defined as systolic blood pressure ≤ 90 mmHg), tachycardia (most often defined as heart rate ≥ 120/min), clinical signs of poor perfusion (eg, prolonged capillary refill time or changes in mental status) and injury type (ie, penetrating wounds) are common pre-hospital transfusion triggers.

CONCLUSIONS

PHTRBC is increasingly used by Emergency Medical Services, but guidelines on when to initiate transfusion are lacking. We identified the most commonly used transfusion criteria, and these findings may provide the basis for consensus-based pre-hospital transfusion protocols.

Pre-hospital transfusion of red blood cells. Part 2: A systematic review of treatment effects on outcomes

The primary aim of this systematic review is to describe the effects of prehospital transfusion of red blood cells (PHTRBC) on patient outcomes. Damage control resuscitation attempts to prevent death through haemorrhage in trauma patients. In this context, transfusion of red blood cells is increasingly used by emergency medical services (EMS). However, evidence on the effects on outcomes is scarce. PubMed and Web of Science were searched through January 2019; 55 articles were included. No randomised controlled studies were identified. While several observational studies suggest an increased survival after PHTRBC, consistent evidence for beneficial effects of PHTRBC on survival was not found. PHTRBC appears to improve haemodynamic parameters, but there is no evidence that shock on arrival to hospital is averted, nor of an association with trauma induced coagulopathy or with length of stay in hospitals or intensive care units. In conclusion, PHTRBC is increasingly used by EMS, but there is no strong evidence for effects of PHTRBC on mortality. Further research with study designs that allow causal inferences is required for more conclusive evidence. The combination of PHTRBC with plasma, as well as the use of individualised transfusion criteria, may potentially show more benefits and should be thoroughly investigated in the future. The review was registered at Prospero (CRD42018084658).

Thinking Out of the (Big) Box: A Wearable Near-Infrared Spectroscopy Monitor for the Helicopter Emergency Medical Service

OBJECTIVE

In prehospital helicopter emergency medical service (HEMS) settings, the medical team has limited monitoring options, usually restricted to systemic variables. Regional tissue oxygenation (rO₂) can be assessed by near-infrared spectroscopy (NIRS), but clinical NIRS monitors are unpractical ("big boxes" and additional cables) in HEMS. As an alternative, we identified a wearable, athlete training NIRS device (Moxy; Idiag, Fehraltorf, Switzerland) and hypothesized that it would be applicable in our HEMS setting.

METHODS

This feasibility study was performed at the Dutch HEMS Lifeliner 1. The Moxy sensor was tested in-flight and on ground. We tested various anatomic measurement spots, and multiple conditions and interventions were imposed to track rO₂.

RESULTS

The rO₂ measurements with the wearable Moxy NIRS device are both feasible and practical in an HEMS setting. Multiple conditions and interventions were tested successfully (eg, tourniquet placement [rO₂↓], muscle compression [rO₂↓], reperfusion [rO₂↑], oxygen administration [rO₂↑], hyperemia [rO₂↑], and venous congestion [rO₂↓]).

CONCLUSION

Our results suggest that rO₂ measurements with the wearable Moxy NIRS device are both feasible and practical in HEMS, and Moxy allows the tracking of simulated pathophysiologic effects on rO₂. Future studies will have to verify our preliminary data and elucidate if and how wearable NIRS monitoring may support treatment in HEMS and improve patient outcome.

When Limb Surgery Has Become the Only Life-Saving Therapy in FOP: A Case Report and Systematic Review of the Literature

Fibrodysplasia ossificans progressiva (FOP) is a rare disease in which heterotopic ossification (HO) is formed in muscles, tendons and ligaments. Traumatic events, including surgery, are discouraged as this is known to trigger a flare-up with risk of subsequent HO. Anesthetic management for patients with FOP is challenging. Cervical spine fusion, ankylosis of the temporomandibular joints, thoracic insufficiency syndrome, restrictive chest wall disease, and sensitivity to oral trauma complicate airway management and anesthesia and pose life-threatening risks. We report a patient with FOP suffering from life-threatening antibiotic resistant bacterial infected ulcers of the right lower leg and foot. The anesthetic, surgical and postoperative challenges and considerations are discussed. In addition, the literature on limb surgeries of FOP patients is systemically reviewed. The 44 year-old female patient was scheduled for a through-knee amputation. Airway and pulmonary evaluation elicited severe abnormalities, rendering standard general anesthesia a rather complication-prone approach in this patient. Thus, regional anesthesia, supplemented with intravenous analgosedation and N₂O-inhalation were performed in this case. The surgery itself was securely planned to avoid any unnecessary tissue damage. Postoperatively the patient was closely monitored for FOP activity by ultrasound and [¹⁸F]PET/CT-scan. One year after surgery, a non-significant amount of HO had formed at the operated site. The systematic review revealed seventeen articles in which thirty-two limb surgeries in FOP patients were described. HO reoccurrence was described in 90% of the cases. Clinical improvement due to improved mobility of the operated joint was noted in 16% of the cases. It should be noted, though, that follow-up time was limited and no or inadequate imaging modalities were used to follow-up in the majority of these cases. To conclude, if medically urgent, limb surgery in FOP is possible even when general anesthesia is not preferred. The procedure should be well-planned, alternative techniques or procedures should be tested prior to surgery and special attention should be paid to the correct positioning of the patient. According to the literature recurrent HO should be expected after surgery of a limb, even though it was limited in the case described.

Prehospital ultrasound in the management of trauma patients: Systematic review of the literature

INTRODUCTION

Emergency ultrasound methods such as Focused Assessment with Sonography in Trauma (FAST) are a widely used imaging method. This examination can be performed to examine the presence of several life-threatening injuries. Early diagnosis may lead to better outcome, but the effect of timely diagnosis in the prehospital setting is not yet clear. Therefore, the aim is to determine the diagnostic accuracy and the effect of prehospital ultrasound performed in (poly)trauma patients.

METHODS

A literature search was performed in PubMed, Embase and Cochrane's Library. Articles were included if prehospital ultrasound was performed as a diagnostic intervention in patients with trauma. The main outcome measures included diagnostic accuracy, changes in prehospital diagnosis/treatment, changes in destination hospital and in-hospital response. Case reports and case series were excluded.

RESULTS

After screening 3343 articles, nine studies met the inclusion criteria. These included three retrospective and six prospective observational studies, with a total number of 2,889 patients. Five studies report at least one change in polytrauma management, ranging from 6% to 48,9% of the cases. The diagnostic accuracy of prehospital ultrasound was adequate in eight (out of nine) articles. High sensitivity and high specificity were found on several endpoints (pneumothorax, free abdominal fluid, haemoperitoneum, both on site and during transport).

CONCLUSION

Prehospital ultrasound led to a change in polytrauma management in all studies that included this as an outcome measure. The diagnostic accuracy was described in eight studies, high sensitivity and specificity were found. Overall, the studies seem to suggest a positive influence of performing ultrasound. However, additional research with homogenous accuracy endpoints and uniformly trained prehospital care providers is recommended.

The P2X7 receptor tracer [11C]SMW139 as an in vivo marker of neuroinflammation in multiple sclerosis: a first-in man study

Purpose

The novel PET tracer [¹¹C]SMW139 binds with high affinity to the P2X₇ receptor, which is expressed on pro-inflammatory microglia. The purposes of this first in-man study were to characterise pharmacokinetics of [¹¹C]SMW139 in patients with active relapsing remitting multiple sclerosis (RRMS) and healthy controls (HC) and to evaluate its potential to identify in vivo neuroinflammation in RRMS.

Methods

Five RRMS patients and 5 age-matched HC underwent 90-min dynamic [¹¹C]SMW139 PET scans, with online continuous and manual arterial sampling to generate a metabolite-corrected arterial plasma input function. Tissue time activity curves were fitted to single- and two-tissue compartment models, and the model that provided the best fits was determined using the Akaike information criterion.

Results

The optimal model for describing [¹¹C]SMW139 kinetics in both RRMS and HC was a reversible two-tissue compartment model with blood volume parameter and with the dissociation rate k₄ fixed to the whole-brain value. Exploratory group level comparisons demonstrated an increased volume of distribution (V_T) and binding potential (BP_ND) in RRMS compared with HC in normal appearing brain regions. BP_ND in MS lesions was decreased compared with non-lesional white matter, and a further decrease was observed in gadolinium-enhancing lesions. In contrast, increased V_T was observed in enhancing lesions, possibly resulting from disruption of the blood-brain barrier in active MS lesions. In addition, there was a high correlation between parameters obtained from 60- to 90-min datasets, although analyses using 60-min data led to a slight underestimation in regional V_T and BP_ND values.

Conclusions

This first in-man study demonstrated that uptake of [¹¹C]SMW139 can be quantified with PET using BP_ND as a measure for specific binding in healthy controls and RRMS patients. Additional studies are warranted for further clinical evaluation of this novel neuroinflammation tracer.

Electronic supplementary material

The online version of this article (10.1007/s00259-019-04550-x) contains supplementary material, which is available to authorized users.

Exploring effects of Souvenaid on cerebral glucose metabolism in Alzheimer's disease

Introduction

Alzheimer's disease (AD) is associated with synapse loss. Souvenaid, containing the specific nutrient combination Fortasyn Connect, was designed to improve synapse formation and function. The NL-ENIGMA study explored the effect of Souvenaid on synapse function in early AD by assessing cerebral glucose metabolism (CMRglc) with ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography (PET).

Methods

We conducted an exploratory double-blind randomized controlled single-center trial. Fifty patients with mild cognitive impairment or mild dementia with evidence of amyloid pathology (cerebrospinal fluid or PET) were stratified for MMSE (20-24 and 25-30) and randomly 1:1 allocated to 24-week daily administration of 125 mL Souvenaid (n = 25) or placebo (n = 25). Dynamic 60-minute [¹⁸F]FDG-PET scans (21 frames) with arterial sampling were acquired at baseline and 24 weeks. CMRglc was estimated by quantitative (K_i) and semiquantitative (standardized uptake value ratio, reference cerebellar gray matter) measurements in five predefined regions of interest and a composite region of interest. Change from baseline in CMRglc was compared between treatment groups by analysis of variance, adjusted for baseline CMRglc and MMSE stratum. Additional exploratory outcome parameters included voxel-based analyses by Statistical Parametric Mapping.

Results

No baseline differences between treatment groups were found (placebo/intervention: n = 25/25; age 66 ± 8/65 ± 7 years; female 44%/48%; MMSE 25 ± 3/25 ± 3). [¹⁸F]FDG-PET data were available for quantitative (placebo n = 19, intervention n = 18) and semiquantitative (placebo n = 20, intervention n = 22) analyses. At follow-up, no change within treatment groups and no statistically significant difference in change between treatment groups in CMRglc in any regions of interest were found by both quantitative and semiquantitative analyses. No treatment effect was found in the cerebellar gray matter using quantitative measures. The additional Statistical Parametric Mapping analyses did not yield consistent differences between treatment groups.

Discussion

In this exploratory trial, we found no robust effect of 24-week intervention with Souvenaid on synapse function measured by [¹⁸F]FDG-PET. Possible explanations include short duration of treatment.

Effects of post-scenario debriefing versus stop-and-go debriefing in medical simulation training on skill acquisition and learning experience: a randomized controlled trial

BACKGROUND

Debriefing is a critical component to promote effective learning during simulation-based training. Traditionally, debriefing is provided only after the end of a scenario. A possible alternative is to debrief specific portions during an ongoing simulation session (stop-and-go debriefing). While this alternative has theoretical advantages, it is not commonly used due to concerns that interruptions disturb the fidelity and adversely affect learning. However, both approaches have not been rigorously compared, and effects on skill acquisition and learning experience are unknown.

METHODS

We randomly assigned 50 medical students participating in a simulation-based cardiopulmonary resuscitation training to either a post-scenario debriefing or stop-and-go debriefing. After four weeks, participants performed a repeat scenario, and their performance was assessed using a generic performance score (primary outcome). A difference of 3 or more points was considered meaningful. A 5-item questionnaire was used to assess the subjective learning experience and the perceived stress level (secondary outcomes).

RESULTS

There was no significant difference between the groups for the performance score (mean difference: -0.35, 95%CI: -2.46 to 1.77, P = 0.748, n = 48). The confidence limits excluding the specified relevant 3-point difference suggest equivalence of both techniques with respect to the primary outcome. No significant differences were observed for secondary outcomes.

CONCLUSIONS

Stop-and-go debriefing does not adversely affect skill acquisition compared to the classic post-scenario debriefing strategy. This finding is reassuring when interruptions are deemed necessary and gives simulation instructors the latitude to tailor the timing of the debriefing individually, rather than adhering to the unsupported dogma that scenarios should not be interrupted.

TRIAL REGISTRATION

As this study is not a clinical trial, it was not registered in a clinical trials register.

Comparison of a Novel Cadaver Model (Fix for Life) With the Formalin-Fixed Cadaver and Manikin Model for Suitability and Realism in Airway Management Training

BACKGROUND

Manikins are widely used in airway management training; however, simulation of realism and interpatient variability remains a challenge. We investigated whether cadavers embalmed with the novel Fix for Life (F4L) embalmment method are a suitable and realistic model for teaching 3 basic airway skills: facemask ventilation, tracheal intubation, and laryngeal mask insertion compared to a manikin (SimMan 3G) and formalin-fixed cadavers.

METHODS

Thirty anesthesiologists and experienced residents ("operators") were instructed to perform the 3 airway techniques in 10 F4L, 10 formalin-fixed cadavers, and 1 manikin. The order of the model type was randomized per operator. Primary outcomes were the operators' ranking of each model type as a teaching model (total rank), ranking of the model types per technique, and an operator's average verbal rating score for suitability and realism of learning the technique on the model. Secondary outcomes were the percentages of successfully performed procedures per technique and per model (success rates in completing the respective airway maneuvers). For each of the airway techniques, the Friedman analysis of variance was used to compare the 3 models on mean operator ranking and mean verbal rating scores.

RESULTS

Twenty-seven of 30 operators (90%) performed all airway techniques on all of the available models, whereas 3 operators performed the majority but not all of the airway maneuvers on all models for logistical reasons. The total number of attempts for each technique was 30 on the manikin, 292 in the F4L, and 282 on the formalin-fixed cadavers. The operators' median total ranking of each model type as a teaching model was 1 for F4L, 2 for the manikin and, 3 for the formalin-fixed cadavers (P < .001). F4L was considered the best model for mask ventilation (P = .029) and had a higher mean verbal rating score for realism in laryngeal mask airway insertion (P = .043). The F4L and manikin did not differ significantly in other scores for suitability and realism. The formalin-fixed cadaver was ranked last and received lowest scores in all procedures (all P < .001). Success rates of the procedures were highest in the manikin.

CONCLUSIONS

F4L cadavers were ranked highest for mask ventilation and were considered the most realistic model for training laryngeal mask insertion. Formalin-fixed cadavers are inappropriate for airway management training.

Portable Blood (Gas) Analyzer in a Helicopter Emergency Medical Service

INTRODUCTION

In prehospital helicopter emergency medical services (HEMS), the medical team frequently manages critical patients with only limited, noninvasive monitoring options on-site and during HEMS transport. To gain deeper insight into the patient's pathology and to track prehospital treatment effects, a point-of-care blood (gas) analyzer appears desirable also in HEMS. Thus, we hypothesized that prehospital blood (gas) analysis is feasible in the HEMS setting.

METHODS

A prehospital evaluation of a portable blood (gas) analyzer (i-Stat 1; Abbott, Chicago, IL) with appropriate laboratory cartridges was performed within the Dutch HEMS Lifeliner 1, serving a region of ∼4.5 million inhabitants. Venous blood (gas) measurements were performed in our HEMS collective in both trauma and nontrauma cases.

RESULTS

The HEMS team identified benefits (eg, portability and speed) and limitations (eg, a narrow operational temperature range) regarding the tested blood (gas) analyzer. Regarding the actual blood (gas) results, the team collected results without major abnormalities but also cases identifying major pathologies, including several cases of marked acidosis, refractory hypoglycemia, or severe anemia.

CONCLUSION

In conclusion, portable blood (gas) analysis proved feasible in an HEMS operation but with relevant limitations. Future studies will have to show how these limitations can be overcome and how the implementation of portable blood (gas) analyzers may support improved patient outcome.

Evolution of heterotopic bone in fibrodysplasia ossificans progressiva: An [18F]NaF PET/CT study

Fibrodysplasia ossificans progressiva (FOP) is a rare, autosomal dominant disorder characterized by heterotopic ossification (HO) in muscles, ligaments and tendons. Flare-ups often precede the formation of HO, resulting in immobilization of joints. Due to progression of the disease without signs of a flare-up, co-existence of a chronic progression of HO has been postulated, but conclusive evidence is lacking. Recently, it has been shown that [¹⁸F]NaF PET/CT is able to identify early ossifying disease activity during flare-ups. Therefore, the purpose of the present study was to assess whether [¹⁸F]NaF PET/CT might also be able to identify the possible presence of chronic progressive HO in FOP. A total of thirteen [¹⁸F]NaF PET/CT scans from five FOP patients were analysed. Scans were acquired over a period of 0.5 to 2 years. Volumes of HO and standardized uptake values (SUV) were obtained based on manual segmentation of CT images. SUV_peak values, defined as the average SUV value of a 1 mL sphere containing the hottest voxel pixels, were obtained. Two out of five patients experienced ≥1 active clinical flare-ups at the time of the [¹⁸F]NaF PET/CT scan. In addition, in four out of five patients, serial scans showed radiological progression of HO (3 to 8 cm³), as assessed by CT volume, in the absence of a clinical flare-up. This volumetric increase was present in 6/47 (12.8%) of identified HO structures and, in all cases, was accompanied by increased [¹⁸F]NaF uptake, with SUV_peak ranging from 8.4 to 17.9. In conclusion, HO may progress without signs of a flare-up. [¹⁸F]NaF PET/CT is able to identify these asymptomatic, but progressive HO lesions, thereby demonstrating the presence of chronic activity in FOP. Consequently, future drugs should not only target new HO formation, but also this chronic HO progression.

Direct comparison of [11C] choline and [18F] FET PET to detect glioma infiltration: a diagnostic accuracy study in eight patients

Background

Positron emission tomography (PET) is increasingly used to guide local treatment in glioma. The purpose of this study was a direct comparison of two potential tracers for detecting glioma infiltration, O-(2-[¹⁸F]-fluoroethyl)-l-tyrosine ([¹⁸F] FET) and [¹¹C] choline.

Methods

Eight consecutive patients with newly diagnosed diffuse glioma underwent dynamic [¹¹C] choline and [¹⁸F] FET PET scans. Preceding craniotomy, multiple stereotactic biopsies were obtained from regions inside and outside PET abnormalities. Biopsies were assessed independently for tumour presence by two neuropathologists. Imaging measurements were derived at the biopsy locations from 10 to 40 min [¹¹C] choline and 20–40, 40–60 and 60–90 min [¹⁸F] FET intervals, as standardized uptake value (SUV) and tumour-to-brain ratio (TBR). Diagnostic accuracies of both tracers were compared using receiver operating characteristic analysis and generalized linear mixed modelling with consensus histopathological assessment as reference.

Results

Of the 74 biopsies, 54 (73%) contained tumour. [¹¹C] choline SUV and [¹⁸F] FET SUV and TBR at all intervals were higher in tumour than in normal samples. For [¹⁸F] FET, the diagnostic accuracy of TBR was higher than that of SUV for intervals 40–60 min (area under the curve: 0.88 versus 0.81, p = 0.026) and 60–90 min (0.90 versus 0.81, p = 0.047). The diagnostic accuracy of [¹⁸F] FET TBR 60–90 min was higher than that of [¹¹C] choline SUV 20–40 min (0.87 versus 0.67, p = 0.005).

Conclusions

[¹⁸F] FET was more accurate than [¹¹C] choline for detecting glioma infiltration. Highest accuracy was found for [¹⁸F] FET TBR for the interval 60–90 min post-injection.

Electronic supplementary material

The online version of this article (10.1186/s13550-019-0523-8) contains supplementary material, which is available to authorized users.

Simplified Methods for Quantification of 18F-DCFPyL Uptake in Patients with Prostate Cancer

Radiolabeled prostate-specific membrane antigen (PSMA) PET has demonstrated promising results for prostate cancer (PCa) imaging. Quantification of PSMA radiotracer uptake is desired as it enables reliable interpretation of PET images, use of PSMA uptake as an imaging biomarker for tumor characterization, and evaluation of treatment effects. The aim of this study was to perform a full pharmacokinetic analysis of 2-(3-(1-carboxy-5-[(6-¹⁸F-fluoro-pyridine-3-carbonyl)-amino]-pentyl)-ureido)-pentanedioic acid (¹⁸F-DCFPyL), a second-generation ¹⁸F-labeled PSMA ligand. On the basis of the pharmacokinetic analysis (reference method), simplified methods for quantification of ¹⁸F-DCFPyL uptake were validated. Methods: Eight patients with metastasized PCa were included. Dynamic PET acquisitions were performed at 0-60 and 90-120 min after injection of a median dose of 313 MBq of ¹⁸F-DCFPyL (range, 292-314 MBq). Continuous and manual arterial blood sampling provided calibrated plasma tracer input functions. Time-activity curves were derived for each PCa metastasis, and ¹⁸F-DCFPyL kinetics were described using standard plasma input tissue-compartment models. Simplified methods for quantification of ¹⁸F-DCFPyL uptake (SUVs; tumor-to-blood ratios [TBRs]) were correlated with kinetic parameter estimates obtained from full pharmacokinetic analysis. Results: In total, 46 metastases were evaluated. A reversible 2-tissue-compartment model was preferred for ¹⁸F-DCFPyL kinetics in 59% of the metastases. The observed k ₄ was small, however, resulting in nearly irreversible kinetics during the course of the PET study. Hence, k ₄ was fixated (0.015) and net influx rate, K_i, was preferred as the reference kinetic parameter. Whole-blood TBR provided an excellent correlation with K_i from full kinetic analysis (R ² = 0.97). This TBR could be simplified further by replacing the blood samples with an image-based, single measurement of blood activity in the ascending aorta (image-based TBR, R ² = 0.96). SUV correlated poorly with K_i (R ² = 0.47 and R ² = 0.60 for SUV normalized to body weight and lean body mass, respectively), most likely because of deviant blood activity concentrations (i.e., tumor tracer input) in patients with higher tumor volumes. Conclusion: ¹⁸F-DCFPyL kinetics in PCa metastases are best described by a reversible 2-tissue-compartment model. Image-based TBRs were validated as a simplified method to quantify ¹⁸F-DCFPyL uptake and might be applied to clinical, whole-body PET scans. SUV does not provide reliable quantification of ¹⁸F-DCFPyL uptake.

Hemorrhage Treatment Adjuncts in a Helicopter Emergency Medical Service

Hemorrhaging is the leading cause of preventable death after trauma. In our helicopter emergency medical service (HEMS), we introduced a bundle of 3 hemostatic adjuncts: 1) tourniquet, 2) hemostatic chitosan-based wound packings, and 3) tranexamic acid (TXA). The real-life frequency of applying these adjuncts in HEMS remains unclear. Therefore, we analyzed our electronic HEMS database regarding the use of these hemostatic adjuncts. We analyzed all subsequent dispatches of our HEMS "Lifeliner 1" within a searchable digital database (01.02.2013-22.05.2018). This HEMS operates 24/7, servicing ∼4.5 million inhabitants of the Netherlands. During the 75-month study period, we registered 15,759 dispatches, of which 8,658 were canceled, and 7,101 included on-site patient care, including 4,928 (69.4%) trauma cases. In total, we recorded 78 tourniquet applications (1.1% of patients), 104 hemostatic wound packings (1.5% of patients), and 1,379 cases with prehospital TXA administration (19.4% of patients). This difference in the use of hemostatics has several contributors, including a possible lack of awareness for tourniquets and procoagulant wound packing, a high proportion of blunt trauma with internal bleeding not accessible to tourniquet or wound packing, and a liberal use of TXA (eg, in patients with unproven hemorrhage). Besides creating awareness for those hemostatic adjuncts, the practical implications of our findings need further evaluation in future studies.

Prehospital cricothyrotomies in a helicopter emergency medical service: analysis of 19,382 dispatches

Background

Creating a patent airway by cricothyrotomy is the ultimate maneuver to allow oxygenation (and ventilation) of the patient. Given the rarity of airway management catastrophes necessitating cricothyrotomy, sufficiently sized prospective randomized trials are difficult to perform. Our Helicopter Emergency Medical Service (HEMS) documents all cases electronically, allowing a retrospective analysis of a larger database for all cases of prehospital cricothyrotomy.

Methods

We analyzed all 19,382 dispatches of our HEMS ‘Lifeliner 1’, since set-up of a searchable digital database. This HEMS operates 24/7, covering ~ 4.5 million inhabitants of The Netherlands. The potential cases were searched and cross-checked in two independent databases.

Results

We recorded n = 18 cases of prehospital cricothyrotomy. In all 18 cases, less invasive airway techniques, e.g., supraglottic devices, were attempted before cricothyrotomy. With exception of 2 cases, at least one attempt of orotracheal intubation had been performed before cricothyrotomy. Out of the 18 cases, 4 were performed by puncture-based technique (Melker), the remaining 14 cases by surgical technique. Indications for cricothyrotomy were diverse, dividable into 9 trauma cases and 9 medical cases.

The procedure was successful in all but one case (17/18, i.e., 94%; with a 95% confidence interval of 72.7–99.9%). Outcome was such that 6/18 patients arrived at the hospital alive. Long term outcome was poor, with only 2/18 patients discharged from hospital alive.

Conclusions

Cricothyrotomy remains, although rare, a regularly occurring requirement in (H)EMS. Our finding of a convincingly high success rate of 94% in trained hands encourages training and a timely performance of cricothyrotomy.

I See Red! Red Light Illumination in Helicopter Air Ambulance Services

Helicopter air ambulance services (HAA) increasingly operate during darkness, and the cockpit crew prefers a dimmed light to be used in the cabin. Our HAA team is currently researching the use of dimmed red light. We encountered a downside to the use of red light-some texts and symbols became virtually invisible.

Statistical Significance Versus Clinical Importance of Observed Effect Sizes: What Do P Values and Confidence Intervals Really Represent?

Effect size measures are used to quantify treatment effects or associations between variables. Such measures, of which >70 have been described in the literature, include unstandardized and standardized differences in means, risk differences, risk ratios, odds ratios, or correlations. While null hypothesis significance testing is the predominant approach to statistical inference on effect sizes, results of such tests are often misinterpreted, provide no information on the magnitude of the estimate, and tell us nothing about the clinically importance of an effect. Hence, researchers should not merely focus on statistical significance but should also report the observed effect size. However, all samples are to some degree affected by randomness, such that there is a certain uncertainty on how well the observed effect size represents the actual magnitude and direction of the effect in the population. Therefore, point estimates of effect sizes should be accompanied by the entire range of plausible values to quantify this uncertainty. This facilitates assessment of how large or small the observed effect could actually be in the population of interest, and hence how clinically important it could be. This tutorial reviews different effect size measures and describes how confidence intervals can be used to address not only the statistical significance but also the clinical significance of the observed effect or association. Moreover, we discuss what P values actually represent, and how they provide supplemental information about the significant versus nonsignificant dichotomy. This tutorial intentionally focuses on an intuitive explanation of concepts and interpretation of results, rather than on the underlying mathematical theory or concepts.

Emergency clamshell thoracotomy in blunt trauma resuscitation: Shelling the paradigm-2 cases and review of the literature

Clamshell thoracotomy (CST) may be indicated and life-saving in carefully selected cases of blunt trauma. As such, the current clinical stance of general contraindication of CST in blunt trauma should be reviewed and criteria developed to accommodate select cases, considering the diversity of injuries resulting from blunt trauma.

First in human evaluation of [18F]PK-209, a PET ligand for the ion channel binding site of NMDA receptors

Background

Efforts to develop suitable positron emission tomography (PET) tracers for the ion channel site of human N-methyl-d-aspartate (NMDA) receptors have had limited success. [¹⁸F]PK-209 is a GMOM derivative that binds to the intrachannel phencyclidine site with high affinity and selectivity. Primate PET studies have shown that the volume of distribution in the brain was reduced by administration of the NMDA receptor antagonist MK-801, consistent with substantial specific binding. The purpose of the present study was to evaluate [¹⁸F]PK-209 in 10 healthy humans by assessing test–retest reproducibility and binding specificity following intravenous S-ketamine administration (0.5 mg ∙ kg⁻¹). Five healthy subjects underwent a test–retest protocol, and five others a baseline-ketamine protocol. In all cases dynamic, 120-min PET scans were acquired together with metabolite-corrected arterial plasma input functions. Additional input functions were tested based on within-subject and population-average parent fractions.

Results

Best fits of the brain time-activity curves were obtained using an irreversible two-tissue compartment model with additional blood volume parameter. Mean test–retest variability of the net rate of influx K_i varied between 7 and 24% depending on the input function. There were no consistent changes in [¹⁸F]PK-209 PET parameters following ketamine administration, which may be a consequence of the complex endogenous ligand processes that affect channel gating.

Conclusions

The molecular interaction between [¹⁸F]PK-209 and the binding site within the NMDA receptor ion channel is insufficiently reproducible and specific to be a reliable imaging agent for its quantification.

Trial registration

EudraCT 2014-001735-36. Registered 28 April 2014

What Do Anesthesiologists Know about p Values, Confidence Intervals, and Correlations: A Pilot Survey

BACKGROUND

Statistical methods form the basis for clinical decision-making in evidence-based anesthesia. Data on the knowledge of anesthesiologists about statistics are lacking. This pilot study aims to provide a first impression of the anesthesiologists' understanding of commonly used concepts in statistics.

METHODS

A cross-sectional pilot survey was performed at a major international anesthesia conference. The questionnaire consisted of three basic multiple-choice questions on the topics "p value," "confidence interval," and "correlation." Results of the questions are reported as percentage of correct answers (95% confidence interval).

RESULTS

65 questionnaires were analyzed. Forty participants were male, and mean age was 40 (standard deviation: 10) years. The question addressing the p value was correctly answered by 15% (95% CI: 8 to 27%) of respondents. The question concerning the 95% confidence interval was answered correctly by 28% (95% CI: 18 to 40%) of participants. For the question about correlation, a correct answer was given by 52% (95% CI: 40 to 64%). None of the participants answered all questions correctly, and 19 participants provided a wrong answer to all questions.

CONCLUSIONS

Anesthesiologists seem to demonstrate a poor understanding of statistical key concepts. Further studies are needed to address statistical knowledge gaps among anesthesiologists more comprehensively.