Demographic Features, Physical Examination Findings, and Medication Use in Hospitalized, Delirious Patients With and Without COVID-19 Infection: A Retrospective Study.

BACKGROUND: Delirium is common in the setting of infection with severe acute respiratory syndrome coronavirus 2. Anecdotal evidence and case reports suggest that patients with delirium in the setting of Coronavirus 2019 (COVID-19) may exhibit specific features, including increased tone, abulia, and alogia. OBJECTIVE: To determine whether differences exist in sociodemographic and medical characteristics, physical examination findings, and medication use in delirious patients with and without COVID-19 infection referred for psychiatric consultation. METHODS: We undertook an exploratory, retrospective chart review of 486 patients seen by the psychiatry consultation service at a tertiary care hospital from March 10 to May 15, 2020. Delirious patients were diagnosed via clinical examination by a psychiatric consultant, and these patients were stratified by COVID-19 infection status. The strata were described and compared using bivariate analyses across sociodemographic, historical, objective, and treatment-related variables. RESULTS: A total of 109 patients were diagnosed with delirium during the study period. Thirty-six were COVID-19+. Median age was 63 years and did not differ between groups. COVID-19+ patients with delirium were more likely to present from nursing facilities (39% vs 11%; Fisher's exact test; P = 0.001) and have a history of schizophrenia (11% vs 0%; Fisher's exact test; P = 0.011). Myoclonus (28% vs 4%; P = 0.002), hypertonia (36% vs 10%; P = 0.003), withdrawal (36% vs 15%; P = 0.011), akinesia (19% vs 6%; P = 0.034), abulia (19% vs 3%; P = 0.004), and alogia (25% vs 8%; P = 0.012) were more common in COVID-19+ patients. COVID-19+ delirious patients were significantly more likely to have received ketamine (28% vs 7%; P = 0.006), alpha-adrenergic agents besides dexmedetomidine (36% vs 14%; P = 0.014), and enteral antipsychotics (92% vs 66%; P = 0.007) at some point. CONCLUSIONS: Patients with COVID-19 delirium referred for psychiatric consultation are more likely to reside in nursing facilities and have a history of schizophrenia than delirious patients without COVID-19. Patients with delirium in the setting of COVID-19 may exhibit features consistent with akinetic mutism. Psychiatrists must assess for such features, as they may influence management choices and the risk of side effects with agents commonly used in the setting of delirium.

Algebraic formulas characterizing an alternative to Guyton's graphical analysis relevant for heart failure.

Although Guyton's graphical analysis of cardiac output-venous return has become a ubiquitous tool for explaining how circulatory equilibrium emerges from heart-vascular interactions, this classical model relies on a formula for venous return that contains unphysiological assumptions. Furthermore, Guyton's graphical analysis does not predict pulmonary venous pressure, which is a critical variable for evaluating heart failure patients' risk of pulmonary edema. Therefore, the purpose of the present work was to use a minimal closed-loop mathematical model to develop an alternative to Guyton's analysis. Limitations inherent in Guyton's model were addressed by 1) partitioning the cardiovascular system differently to isolate left ventricular function and lump all blood volumes together, 2) linearizing end-diastolic pressure-volume relationships to obtain algebraic solutions, and 3) treating arterial pressures as constants. This approach yielded three advances. First, variables related to morbidities associated with left ventricular failure were predicted. Second, an algebraic formula predicting left ventricular function was derived in terms of ventricular properties. Third, an algebraic formula predicting flow through the portion of the system isolated from the left ventricle was derived in terms of mechanical properties without neglecting redistribution of blood between systemic and pulmonary circulations. Although complexities were neglected, approximations necessary to obtain algebraic formulas resulted in minimal error, and predicted variables were consistent with reported values.