Organ System Network Disruption in Nonsurvivors of Critically Ill Patients.

OBJECTIVES: As interactions of each organ system have been conceptually known to play an important role during life-threatening conditions, we quantitatively evaluated the organ system interactions in critically ill patients and examined the difference in the organ system network structure between the survivors and the nonsurvivors. DESIGN: Prospective observational study. SETTINGS: An ICU of a university hospital. PATIENTS: Two hundred and eighty-two patients who were admitted to the ICU. INTERVENTIONS: Blood samples were obtained at ICU admission. MEASUREMENTS AND MAIN RESULTS: We analyzed the associations among nine representative laboratory variables of each organ system using network analysis. We compared the network structure of the variables in the 40 nonsurvivors with that in the 40 survivors. Their baseline characteristics, including the degree of organ dysfunction, were matched using propensity score matching method. Network structure was quantitatively evaluated using edge (significant correlation among variables evaluated by the p value), weight (connective strength of edge evaluated by coefficient), and cluster (group with tight connection evaluated by edge betweenness). The number of edges among the nine variables was significantly fewer for the nonsurvivors than for the severity-matched survivors (3 vs 12; p = 0.035). The mean weight of edges was significantly smaller for the nonsurvivors (0.055 vs 0.119; p = 0.007). The nine laboratory variables for the nonsurvivors were divided into a significantly larger number of clusters (7 vs 2; p = 0.001). Statistical conclusions were preserved with Bonferroni multiple comparison procedure. These findings were consistently observed in comparison of the 40 nonsurvivors with all the survivors. CONCLUSIONS: This study, as a preliminary proof-of-concept, quantitatively demonstrated a more disrupted network structure of organ systems in the nonsurvivors compared with that in the survivors. These observations suggest the necessity of assessment for organ system interactions to evaluate critically ill patients.

Plasma cell myeloma of the skull base: report of two cases.

Plasma cell myeloma (PCM) of the skull base is rarely encountered in neurosurgical practice. PCM has a wide spectrum of pathology, including a quite benign, solitary plasmacytoma (SPC), and an extremely malignant, multiple myeloma (MM) at the two ends of the spectrum. We have described two patients with PCM of the skull base, of which one harbored SPC, and the other progressed to MM. In case 1, a 46-year-old man presented with left multiple cranial nerve impairments and had a large skull base tumor. Subtotal removal was performed. The specimen and general examination, including bone marrow aspiration, revealed SPC. Postoperatively 50Gy of external radiotherapy was administered. The patient has no manifestation of MM 24 months after the initial presentation. In case 2, a 53-year-old woman presented with left abducens palsy and had a left petroclival osteolytic mass. Gross total resection was performed. The specimen revealed a plasmablastic tumor, i.e., myeloma. General examination established the diagnosis of MM. She was administrated adjuvant chemotherapy and autologous bone marrow transplantation. She is alive without local recurrence 30 months after the initial presentation.