The pLA measurements improve prediction of mortality, surgery, and MODS. Lactate may improve the identification of patients who require monitoring, resources, and resuscitation.

BACKGROUND Tissue oximetry (StO2) plus a vascular occlusion test is a noninvasive technology that targets indices of oxygen uptake and delivery. We hypothesize that prehospital tissue oximetric values and vascular occlusion test response can predict the need for in-hospital lifesaving interventions (LSI). METHODS We conducted a prospective, blinded observational study to evaluate StO2 slopes to predict the need for LSI. We calculated the DeO2 slope using Pearson’s coefficients of regression (r2) for the first 25% of descent and the ReO2 slope using the entire recovery interval. The primary outcome was LSI defined as the need for emergent operation or transfusion in the first 24 hours of hospitalization. We created multivariable logistic regression models using covariates of age, sex, vital signs, lactate, and mental status. RESULTS We assessed StO2 in a convenience sample of 150 trauma patients from April to November of 2009. In-hospital mortality was 3% (95% confidence interval [CI], 1.1–7.6); 31% (95% CI, 24–39) were admitted to the intensive care unit, 6% (95% CI, 2.8–11.1) had an emergent operation, and 10% (95% CI, 5.7–15.9) required transfusion. Decreasing DeO2 was associated with a higher proportion of patients requiring LSI. In the multivariate model, the association between the need for LSI and DeO2, Glasgow Coma Scale, and age persists. CONCLUSION Prehospital DeO2 is associated with need for LSI in our trauma population. Further study of DeO2 is warranted to determine whether it can be used as an adjunct triage criterion or an endpoint for resuscitation. LEVEL OF EVIDENCE III, observational study.

Point-of-care testing (POCT) in low-resource settings requires tools that can operate independently of typical laboratory infrastructure. Due to its favorable signal-to-background ratio, a wide variety of biomedical tests utilize fluorescence as a readout. However, fluorescence techniques often require expensive or complex instrumentation and can be difficult to adapt for POCT. To address this issue, we developed a pocket-sized fluorescence detector costing less than $15 that is easy to manufacture and can operate in low-resource settings. It is built from standard electronic components, including an LED and a light dependent resistor, filter foils and 3D printed parts, and reliably reaches a lower limit of detection (LOD) of ≈ 6.8 nM fluorescein, which is sufficient to follow typical biochemical reactions used in POCT applications. All assays are conducted on filter paper, which allows for a flat detector architecture to improve signal collection. We validate the device by quantifying in vitro RNA transcription and also demonstrate sequence-specific detection of target RNAs with an LOD of 3.7 nM using a Cas13a-based fluorescence assay. Cas13a is an RNA-guided, RNA-targeting CRISPR effector with promiscuous RNase activity upon recognition of its RNA target. Cas13a sensing is highly specific and adaptable and in combination with our detector represents a promising approach for nucleic acid POCT. Furthermore, our open-source device may be used in educational settings, through providing low cost instrumentation for quantitative assays or as a platform to integrate hardware, software and biochemistry concepts in the future.

Objective Serum lactate elevations are associated with morbidity and mortality in trauma patients, but their value in prehospital medical patients prior to resuscitation is unknown. We sought to assess the distribution of blood lactate concentrations prior to intravenous (IV) resuscitation and examine the association of elevation on in-hospital death. Methods A convenience sample of adult patients over 14 months who received an IV line by eight EMS agencies in Western Pennsylvania had lactate measurement prior to any IV treatment. We assessed the lactate values and any relationship between these and hospital mortality (our primary outcome) and admission to the intensive care unit (ICU). We also compared the ability of lactate to discriminate outcomes with a prehospital critical illness score using age, Glasgow Coma Score, and initial vital signs. Results We included 673 patients, among whom 71 (11%) were admitted to the ICU and 21 (3.1%) died in-hospital. Elevated lactate (≥2 mmol/L) occurred in 307 (46%) patients and was strongly associated with hospital death after adjustment for known covariates (odds ratio = 3.57, 95% confidence interval [CI]: 1.10, 11.6). Lactate ≥2 mmol/L had a modest sensitivity (76%) and specificity (55%), and discrimination for hospital death (area under the curve [AUC] = 0.66, 95%CI: 0.56, 0.75). Compared to the prehospital critical illness score alone (AUC = 0.69, 95% CI: 0.59, 0.80), adding lactate to the score offered modest improvement (net reclassification improvement = 0.63, 95%CI: 0.23, 1.01, p < 0.05). Conclusions Initial lactate concentration in our prehospital medical patient population was associated with hospital mortality. However, it is a modest predictor of outcome, offering similar discrimination to a prehospital critical illness score.

Background Multiple studies have demonstrated varying rates of successful endotracheal intubation (ETI). Until the application of video laryngoscopy, little information regarding prehospital intubation could be analyzed objectively by individuals other than the provider performing the ETI. Objective To evaluate the association of variables recorded during video laryngoscopy and successful ETI attempts, defined as placing the endotracheal tube in the trachea. Methods We retrospectively reviewed intubations performed by a single helicopter emergency medical service (HEMS) using a video larygoscope from March 1, 2010, to October 1, 2010. All videos were de-identified and analyzed by a single researcher. Time intervals (e.g., attempt time) and intubation process variables (e.g., Cormack-Lehane [C-L] view) were abstracted from all videos. Time intervals were begun when the laryngoscope blade passed the lips and entered the oral cavity (entry). We describe variables using means and standard deviations (continuous), medians with interquartile ranges (ordinal), and percentages with 95% confidence intervals (categorical). We then looked at univariate associations between these variables and ETI success using logistic regression. Results We recorded 116 intubations during the study period. Twenty-nine recordings were either incomplete (n = 26) or of insufficient quality for analysis (n = 3). The remaining 87 videos represented 87 different patients with a total of 102 attempts at laryngoscopy. Thirty-six providers performed 64 cases, with the majority of providers (n = 21) performing only one intubation. The first-pass success rate in this series was 76% (n = 66), with 98% success within three attempts. Successful ETI attempts had lower entry–to–percentage of glottic opening (POGO) times (16.6 sec vs. 32.1 sec, p = 0.013), entry–to–first view of the endotracheal tube or entry-to-tube times (17.6 sec vs. 27.4 sec, p = 0.04), higher POGO scores (76 vs. 39, p < 0.001), and a lower C-L view (one vs. three, p < 0.001). Recognized esophageal intubation was more likely to occur during unsuccessful ETI attempts (43% vs. 8%, p < 0.001). Conclusion Video laryngoscopy can measure multiple components of ETI performance. Successful ETI attempts have significantly shorter entry-to-POGO times and entry-to-tube times, obtain better views of the glottic opening (POGO and C-L view), and have a lower incidence of recognized esophageal intubation.

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