Establishing a Benchmark for Iatrogenic Hemodilution and Blood Transfusion in Long-Segment Spine Fusion Surgery.

STUDY DESIGN: Single-center retrospective cohort study. OBJECTIVE: To identify risk factors for transfusion during long-segment thoracolumbar fusion surgery and benchmark cutoffs that could be used by the operative team to guide the use of transfusion. SUMMARY OF BACKGROUND DATA: Perioperative transfusion for patients undergoing long-segment thoracolumbar fusion surgery is common. To date, no standardized intra- and perioperative management of transfusion administration has been defined. METHODS: Patients who underwent thoracolumbar fusion surgeries of 8 or more levels between 2015 and 2020 were identified. Patient demographics, surgical details, anesthesia and critical care records, and laboratory data were compared between patients who received intraoperative and postoperative blood transfusions and those who did not. Univariate and multivariate propensity-matched analyses were performed to identify independent predictors for blood transfusion, and ordinal analysis was performed to identify possible benchmark cutoffs. RESULTS: Among 233 patients identified who underwent long-segment fusions, 133 (57.1%) received a blood transfusion. Multivariate propensity-matched logistic regression showed that intravenous (IV) fluid volume was an independent predictor for transfusion (transfusion group 8051 mL vs. non-transfusion group 5070 mL, P<0.01). Patients who received ≥4 L total IV fluids were more likely to undergo transfusion than those who received <4 L (93.2% vs. 50.7%, P<0.01). Those receiving total IV fluids at a rate ≥60 mL/Kg (OR 10.45; 95% CI: 2.62-41.72, P<0.01) or intraoperative IV fluids at a rate ≥9 mL/Kg/hr (OR 4.46; 95% CI: 1.39-14.32, P<0.01) were more likely to require transfusions. CONCLUSIONS: IV fluid administration is an independent predictor for blood transfusion after long-segment fusion surgery. Limiting IV fluid administration may prevent iatrogenic hemodilution and decrease transfusion rates. These data can be used to create perioperative protocols with the goal of decreasing transfusion rates when not indicated and allowing earlier administration when indicated.

Administrative records-based criterion measures.

This paper covers considerations in using criterion measures based on administrative data. We begin with a conceptual framework for understanding and evaluating administrative criterion measures as "objective" rather than (ratings-based) assessments of job performance. We then describe the associated advantages (e.g., availability) and disadvantages (e.g., contamination) of using administrative data for criterion-related validation purposes. Best practices in the use of administrative data for validation purposes, including procedures for (a) handling missing data, (b) performing data checks, and (c) reporting detailed decision rules so future researchers can replicate the analyses are also described. Finally, we discuss "modern data management" approaches for improving administrative data for supporting organizational decision-making.

Surgical management of hepatocellular carcinoma after Fontan procedure.

The Fontan operation has successfully prolonged the lives of patients born with single-ventricle physiology. A long-term consequence of post-Fontan elevation in systemic venous pressure and low cardiac output is chronic liver inflammation and cirrhosis, which lead to an increased risk of hepatocellular carcinoma (HCC). Surgical management of patients with post-Fontan physiology and HCC is challenging, as the requirement for adequate preload in order to sustain cardiac output conflicts with the low central venous pressure (CVP) that minimizes blood loss during hepatectomy. Consequently, liver resection is rarely performed, and most reports describe nonsurgical treatments for locoregional control of the tumors in these patients. Here, we present a multidisciplinary approach to a successful surgical resection of a HCC in a patient with Fontan physiology.

Perioperative use of cuffed endotracheal tubes is advantageous in young pediatric burn patients.

Uncuffed endotracheal tubes traditionally have been preferred over cuffed endotracheal tubes in young pediatric patients. However, recent evidence in elective pediatric surgical populations suggests otherwise. Because young pediatric burn patients can pose unique airway and ventilation challenges, we reviewed adverse events associated with the perioperative use of cuffed and uncuffed endotracheal tubes. We retrospectively reviewed 327 cases of operating room endotracheal intubation for general anesthesia in burned children 0-10 years of age over a 10-year period. Clinical airway outcomes were compared using multivariable logistic regression, controlling for relevant patient and injury characteristics. Compared to those receiving cuffed tubes, children receiving uncuffed tubes were significantly more likely to demonstrate clinically significant loss of tidal volume (odds ratio 10.62, 95% confidence interval 2.2-50.5) and require immediate reintubation to change tube size/type (odds ratio 5.54, 95% confidence interval 2.1-13.6). No significant differences were noted for rates of post-extubation stridor. Our data suggest that operating room use of uncuffed endotracheal tubes in such patients is associated with increased rates of tidal volume loss and reintubation. Due to the frequent challenge of airway management in this population, strategies should emphasize cuffed endotracheal tube use that is associated with lower rates of airway manipulation.

High-frequency oscillatory ventilation: lessons learned from mechanical test lung models.

OBJECTIVE: Review data obtained from high-frequency oscillatory ventilation (HFOV) and mechanical test lung models with respect to delivered tidal volume, distal pressure transmission, endotracheal tube cuff leaks, and simulated clinical conditions. DESIGN: Review of selected studies from PubMed, published abstracts, and institutional mechanical test lung data. RESULTS: Tidal volume delivery during HFOV is altered by oscillatory pressure amplitude (DeltaP), frequency (Hz), percent inspiratory time (IT%), and patient variables. Distal (carinal) oscillatory pressure amplitude transmission is directly correlated with endotracheal tube diameter and peripheral airway resistance. Endotracheal tube cuff leaks promote egress of tracheal gas while attenuating distal oscillatory pressure amplitude and tidal volume transmission. Simulated clinical conditions (e.g., increased distal airway resistance, mainstem intubation) may increase observed DeltaP, whereas mean airway pressure is decreased with air leaks. CONCLUSION: Mechanical test lung and artificial trachea simulations may provide useful information on the interaction of HFOV with altered lung mechanics and may contribute to the formulation of HFOV clinical strategies. Important limitations of these models include absence of gas exchange, histologic and biologic markers, or hemodynamic data.

Evaluation of unexplained dyspnea in a young athletic male with pectus excavatum.

Pectus excavatum (PE) is a relatively common congenital deformity of the anterior chest wall associated with reduced exercise capacity. Uncertainty exists over the nature of physiologic impairment in PE. Evidence suggests that myocardial compression exerted by the displaced sternum on the right heart chambers, disables the ability of the heart to augment stroke volume during exercise. This case study describes the evaluation of an athletic 20 year old Caucasian male, lifelong non-smoker, with severe pectus deformity and previous fixation procedure to repair a sternal fracture. The patient performed an incremental cycle ergometer exercise test to determine the etiology of his dyspnea with exertion. The patient demonstrated normal work output and normal aerobic capacity but displayed dynamic hyperinflation. Mechanical restriction of tidal volume expansion appeared to be the major contributors to exercise limitation. These results are compared and contrasted with similar cases reported in the literature. Key PointsPectus excavatum (PE) is a relatively common phenomenon affecting approximately 1 in 300 births, with a 9:1 ratio of male to female rate of incidence.The etiology or exercise limitation is most frequently due to cardiovascular limitation due to the compression of the sternum upon the myocardium, impairing the ability to augment stroke volume.The Pectus Severity Index (PSI) is a useful indicator of pectus severity.Cardiopulmonary exercise testing provides useful data to distinguish between cardiovascular limitation, ventilatory limitation, or deconditioning in the evaluation of PE.In this case study, ventilatory limitation was due to the mechanical restriction of the thoracic cavity.

Pulmonary hemorrhage syndrome associated with an autochthonous case of dengue hemorrhagic fever.

Dengue fever is a major public health problem worldwide. Dengue hemorrhagic fever, a much rarer form of the disease, occurs when a person previously infected with dengue is re-infected with a different viral serotype. In recent years the infection rates of dengue and both clinical syndromes have increased along the United States-Mexico border. We present the case of a 61-year-old Laotian female who presented with a 1-week history of fever, altered mental status, oral ulceration, and rash. The patient developed diffuse pulmonary hemorrhage and anemia requiring multiple transfusions. She eventually sustained multi-organ system failure and expired. Both the titer data and serologies were consistent with the diagnosis of dengue hemorrhagic fever. We hypothesize that this syndrome was the result of re-infection occurring within the United States. This case is also unusual in that it is the second reported in the literature of pulmonary hemorrhages associated with dengue hemorrhagic fever.

Development of the nasal chemosensory organs in two terrestrial anurans: the directly developing frog, Eleutherodactylus coqui (Anura: Leptodactylidae), and the metamorphosing toad, Bufo americanus (Anura: Bufonidae).

Nearly all vertebrates possess an olfactory organ but the vomeronasal organ is a synapomorphy for tetrapods. Nevertheless, it has been lost in several groups of tetrapods, including aquatic and marine animals. The present study examines the development of the olfactory and vomeronasal organs in two terrestrial anurans that exhibit different developmental modes. This study compares the development of the olfactory and vomeronasal organs in metamorphic anurans that exhibit an aquatic larva (Bufo americanus) and directly developing anurans that have eliminated the tadpole (Eleutherodactylus coqui). The olfactory epithelium in larval B. americanus is divided into dorsal and ventral branches in the rostral and mid-nasal regions. The larval olfactory pattern in E. coqui has been eliminated. Ontogeny of the olfactory system in E. coqui embryos starts to vary substantially from the larval pattern around the time of operculum development, the temporal period when the larval stage is hypothesized to have been eliminated. The nasal anatomy of the two frogs does not appear morphologically similar until the late stages of embryogenesis in E. coqui and the terminal portion of metamorphosis in B. americanus. Both species and their respective developing offspring, aquatic tadpoles and terrestrial egg/embryos, possess a vomeronasal organ. The vomeronasal organ develops at mid-embryogenesis in E. coqui and during the middle of the larval period in B. americanus, which is relatively late for neobatrachians. Development of the vomeronasal organ in both frogs is linked to the developmental pattern of the olfactory system. This study supports the hypothesis that the most recent common ancestor of tetrapods possessed a vomeronasal organ and was aquatic, and that the vomeronasal organ was retained in the Amphibia, but lost in some other groups of tetrapods, including aquatic and marine animals.

Repetitive hypoglycemia in young rats impairs hippocampal long-term potentiation.

Mechanisms underlying cognitive dysfunction in young diabetic children are poorly understood, and may include synaptic dysfunction from insulin-induced hypoglycemia. We developed a model of repetitive insulin-induced hypoglycemia in young rats and examined hippocampal long-term potentiation, an electrophysiologic assay of synaptic plasticity, 3-5 d after the last hypoglycemic event. Three hypoglycemic events between postnatal d 21-25 produced modest cortical (17 +/- 2.9 dead neurons per section in parasagittal cortex), but not hippocampal, neuron death quantified by Fluoro-Jade B staining. There was no change in neurogenesis in the hippocampal dentate granule cell region by quantification of bromodeoxyuridine incorporation. Although normal baseline hippocampal synaptic responses were elicited from hippocampal slices from hypoglycemic animals, long-term synaptic potentiation could not be induced in hippocampal slices from rats subjected to hypoglycemia. These results suggest that repetitive hypoglycemia in the developing brain can cause selective impairment of synaptic plasticity in the absence of cell death, and without complete disruption of basal synaptic transmission. We speculate that impaired synaptic plasticity in the hippocampus caused by repetitive hypoglycemia could underlie memory and cognitive deficits observed in young diabetic children, and that cortical neuron death caused by repetitive hypoglycemia in the developing brain may contribute to other neurologic, cognitive, and psychological problems sometimes encountered in diabetic children.

Mathematical modeling of decision making: a soft and fuzzy approach to capturing hard decisions.

This research focuses on a modeling approach and set of mathematical tools that were derived from research on intelligence systems, namely fuzzy system modeling. This study systematically evaluates these tools as an approach for modeling human decision making, contrasting the approach with more traditional methods based on regression. The research was conducted using experts and a simulated task environment related to allocating rewards in the form of merit pay. The results indicate that fuzzy system models generally perform as well as or better than both linear and nonlinear regression methods in terms of model fit. These results are discussed in terms of issues regarding modeling precision versus parsimony, the value of adaptive modeling techniques, empirical versus subjective approaches to model building, and individual differences in judgment strategies. Potential applications of this research include using the modeling approach studied to build higher-fidelity models that yield new insights and a better understanding of decision-making strategies and environments.

Nuclear translocation of nuclear transcription factor-kappa B by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors leads to transcription of p53 and cell death in dopaminergic neurons.

We describe a new molecular mechanism of cell death by excitotoxicity mediated through nuclear transcription factor kappa B (NF kappa B) in rat embryonic cultures of dopaminergic neurons. Treatment of mesencephalic cultures with alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) resulted in a number of changes that occurred selectively in dopaminergic neurons, including persistent elevation in intracellular Ca(2+) monitored with Fura-2, and a significant increase in intramitochondrial oxidation of dihydrorhodamine 123, probably associated with transient increase of mitochondrial permeability, cytochrome c release, nuclear translocation of NF kappa B, and transcriptional activation of the oncogene p53. Interruption of any of these steps by specific antagonists prevented neurite pruning and programmed cell death. In contrast, cell death was not prevented by caspase antagonists and only partly prevented by nitric-oxide synthase inhibitors. This signal transduction pathway might be a contributing mechanism in ongoing neuronal death in Parkinson disease.