Evaluation of methodologic variables of the in vitro lymphocyte transformation assay

Optimum methodologic variables for assessing cellular immunity by in vitro lymphocyte transformation (LT) were determined using spherulin and coccidioidin antigens. This study was conducted in an area endemic for coccidioidomycosis and included healthy, coccidioidomycosis skin test positive (STP) and negative (STN) subjects, and patients with mild, acute disease. The authors examined the relationship between coccidioidin (1:100) and spherulin (low dose) skin test reactivity and lymphocyte transformation (LT) responses to the same antigens. Counts per minute (CPM) and stimulation index (SI) as methods of expressing tritiated thymidine uptake were compared. The LT assays were set up in duplicate test systems using autologous and homologous plasma. Both antigens differentiated between STP and STN groups (P less than or equal to 0.001-0.004), but values obtained with spherulin-induced LT were greater than those using coccidioidin (P less than 0.001). Values in CPM and SI were greater in the spherulin-induced LT assay using autologous compared with AB plasma. Specifically, for detecting cellular immunity to coccidioidomycosis, the combination of spherulin-induced LT using autologous plasma and expressing the results in CPM gave the best discrimination between STP and STN subjects. Based on epidemiologic data, the latter method also appeared more sensitive than the skin test in detecting cellular immunity to coccidioidomycosis. In general, these data illustrate the variable effectiveness of different antigens for inducing LT responses and further show how different plasma sources affect the LT response. Finally, these data suggest that lymphocyte blast transformation results expressed as CPM may give more consistent values and better discrimination between immune and nonimmune subjects than results expressed as stimulation indices.     

Intermittent subclavian artery occlusion following clavicular fracture

Although fractures of the clavicle are common, complications are rare. A 41 year old painter developed two uncommon complications of clavicular fracture, mechanical intermittent subclavian artery occlusion and subclavian vein thrombosis. Both conditions were clearly identified on the clinical symptoms and signs and confirmed with dynamic angiography and computerised tomography. Operative intervention led to complete resolution of symptoms.     

Comparison of cardiac output determined by bioimpedance, thermodilution, and the Fick method.

BACKGROUND: Cardiac output can be determined by using a variety of methods. OBJECTIVES: To determine the precision and bias between 3 methods for determining cardiac output: bioimpedance, thermodilution, and the Fick method. METHODS: Cardiac output was determined by using bioimpedance via neck and thorax patches and thermodilution via pulmonary artery catheter in 46 patients in the intensive care unit. A subset of 15 patients also had cardiac output determined by using the Fick method. RESULTS: Mean (SD) cardiac output in all patients was 6.3 (2.2) L/min by thermodilution and 5.6 (2.0) L/min by bioimpedance. In the 15 patients in whom all 3 methods were used, mean cardiac output was 6.0 (1.7) L/min by thermodilution, 5.3 (1.7) L/min by bioimpedance, and 8.6 (4.5) L/min by the Fick method. Bias and precision (mean difference +/- 2 SDs) were 0.7 +/- 2.9 L/min between thermodilution and bioimpedance, 1.7 +/- 3.8 L/min between the Fick method and thermodilution, and 2.4 +/- 4.7 L/min between the Fick method and bioimpedance. CONCLUSION: Bioimpedance, thermodilution, and Fick determinations of cardiac outputs are not interchangeable in a heterogeneous population of critically ill patients.     

Family Centered Practice During Pediatric Death in an Out of Hospital Setting

Objective: To understand effective ways for EMS providers to interact with distressed family members during a field intervention involving a recent or impending out-of-hospital (OOH) pediatric death. Methods: Eight focus groups with 98 EMS providers were conducted in urban and rural settings between November 2013 and March 2014. Sixty-eight providers also completed a short questionnaire about a specific event including demographics. Seventy-eight percent of providers were males, 13% were either African American or Hispanic, and the average number of years in EMS was 16 years. They were asked how team members managed the family during the response to a dying child, what was most helpful for families whose child suddenly and unexpectedly was dead in the OOH setting, and what follow up efforts with the family were effective. Results: The professional response by the EMS team was critical to family coping and getting necessary support. There were several critical competencies identified to help the family cope including: (1) that EMS provide excellent and expeditious care with seamless coordination, (2) allowing family to witness the resuscitation including the attempts to save the child's life, and (3) providing ongoing communication. Whether the child is removed from the scene or not, keeping the family appraised of what is happening and why is critical. Exclusion of families from the process in cases of suspected child abuse is not warranted. Giving tangible forms of support by calling friends, family, and clergy, along with allowing the family time with the child after death, giving emotional support, and follow-up gestures all help families cope. Conclusion: The study revealed effective ways for EMS providers to interact with distressed family members during an OOH pediatric death     

Lactate profiles as a resuscitation assessment tool in a rat model of battlefield hemorrhage resuscitation

Time profiles of arterial lactate concentrations have been proposed as markers for both the degree of physiological derangement during shock and effectiveness of clinical resuscitation, but have not been evaluated for use in short-term experimental protocols. We developed two quantitative mixed models of sequential arterial lactate concentrations to evaluate competing low-volume (<4 mL/kg) battlefield resuscitation therapies in a rat model of acute severe hemorrhagic shock: a simple linear additive model and a nonlinear mechanistic model that described lactate profiles in a continuous trajectory with a defined turning point. Data were obtained during a study evaluating a novel hemoglobin polymer (OxyVita) in a cocktail of hypertonic saline and Hextend as an alternative to standard Hextend. Fluids were either infused by titration to a mean systolic pressure of 60 mmHg or as a single bolus. Parameter estimates derived from both models were assessed for evidence of treatment efficacy and as indicators of short-term survival. A cocktail of hypertonic saline and Hextend was superior to standard Hextend in enhancing survival; however, lactate profiles did not differ between treatments. Regardless of resuscitation regimen, animals surviving to at least 60 min posthemorrhage can be discriminated from nonsurvivors by significantly lower peak lactates (a difference of at least 3 mM; P < 0.001), and all survivors exhibited a decline in lactate with resuscitation. Sequential measurements of lactate over relatively short time frames during resuscitation are of value in assessing both response to resuscitation and short-term mortality.     

Novel computational methods on electronic health record yields new estimates of transfusion-associated circulatory overload in populations enriched with high-risk patients

Background

Transfusion-associated circulatory overload (TACO) is a severe adverse reaction (AR) contributing to the leading cause of mortality associated with transfusions. As strategies to mitigate TACO have been increasingly adopted, an update of prevalence rates and risk factors associated with TACO using the growing sources of electronic health record (EHR) data can help understand transfusion safety.

Study Design and Methods

This retrospective study aimed to provide a timely and reproducible assessment of prevalence rates and risk factors associated with TACO. Novel natural language processing methods, now made publicly available on GitHub, were developed to extract ARs from 3178 transfusion reaction reports. Other patient-level data were extracted computationally from UCSF EHR between 2012 and 2022. The odds ratio estimates of risk factors were calculated using a multivariate logistic regression analysis with case-to-control matched on sex and age at a ratio of 1:5.

Results

A total of 56,208 patients received transfusions (total 573,533 units) at UCSF during the study period and 102 patients developed TACO. The prevalence of TACO was estimated to be 0.2% per patient (102/total 56,208). Patients with a history of coagulopathy (OR, 1.36; 95% CI, 1.04–1.79) and transplant (OR, 1.99; 95% CI, 1.48–2.68) were associated with increased odds of TACO.

Discussion

While TACO is a serious AR, events remained rare, even in populations enriched with high-risk patients. Novel computational methods can be used to find and continually surveil for transfusion ARs. Results suggest that patients with history or presence of coagulopathy and organ transplant should be carefully monitored to mitigate potential risks of TACO.