Plastic Syringes Instead of Heparin-added Dedicated Syringes for Blood Gas Analysis: A Prospective Observational Study.

Introduction: Blood gas analysis is an important test for making quick and important clinical decisions, and it is recommended that a dedicated syringe that contains heparin be used to measure blood gas. We hypothesized that a plastic syringe could be used as a less-expensive substitute for a dedicated syringe, given that the test is performed immediately after collection. Methods: This single-center, prospective, observational study involved patients admitted to the Kanoya Medical Center (Kagoshima, Japan) between July 2020 and March 2021, who were requiring blood gas analysis using a dedicated syringe under arterial line (A-line) monitoring. There were no exclusion criteria. Two samples were collected from each patient using a dedicated syringe, and one sample was collected using a plastic syringe. To determine clinical substitutability, Bland-Altman analysis was performed. Results: A total of 60 samples from 20 consecutive patients were collected and assayed. The mean patient age was 72 years, and 75% patients were men. The 95% limit of agreement for pH, PCO2, PO2, Na, K, Ca, and SO2 were similar for both dedicated and plastic syringes. HCO3 and BE were significantly higher in the samples taken with plastic syringes, whereas Hb and Ht could not be measured accurately with any syringe. Conclusions: The use of plastic syringes in place of dedicated syringes is generally considered acceptable for most items considering that measurement is performed within 3 min of collection, and the cost of medical materials may be reduced. Regardless of the type of syringe, caution should be exercised in interpreting the results of measuring Hb and Ht using a blood gas analyzer.

Changes in cardiac acoustic biomarkers before and after cardiac events in a patient with right-sided heart failure due to cor pulmonale.

Chronic heart failure (HF) has various phenotypes. It is accompanied by repeated hospitalizations over a long period. Therefore, accumulating long-term observational data of patients with various backgrounds is important to establish a prediction technology for the exacerbation of HF. In a patient with chronic right-sided HF caused by cor pulmonale, heart sounds and electrocardiograms were recorded at home or our hospital twice a week for 7 months including the stable (31 days), pre-exacerbation (2 weeks just before the onset of exacerbation), and hospitalization periods and quantified as cardiac acoustic biomarkers (CABs) using AUDICOR technology (Inovise Medical, Inc., Portland, OR, USA). The relationship between the change in CABs and hospitalization events due to HF were investigated. During the pre-exacerbation period just before the onset of exacerbation of HF leading to hospitalization, inaudible changes in the third heart sound (S3) strength that were probably derived from the right heart were observed. Although the values of the fourth heart sound (S4) strength were high during the stable and pre-exacerbation period, values decreased markedly during hospitalization. These findings suggest that CABs including S3 and S4 are useful for the early detection of signs of HF exacerbation. Learning Objective: In a case of chronic right-sided heart failure, the change in the third heart sound (S3) caused by the right ventricle could be detected using cardiac acoustic biomarkers in exacerbations of heart failure. Even if S3 is inaudible by auscultation, it is possible to observe its changes using quantification technology.

Intermittent but not sustained hypoxia activates orexin-containing neurons in mice.

Hypothalamic orexin-containing neurons are activated by CO2 and contribute to hypercapnic ventilatory activation. However, their role in oxygen-related regulation of breathing is not well defined. In this study, we examined whether an experimental model mimicking apnea-induced repetitive hypoxemia (intermittent hypoxia [IH]) activates orexin-containing neurons. Mice were exposed to IH (5×5min at 10% O2), intermittent hyperoxia (IO; 5×5min at 50% O2), sustained hypoxia (SH; 25min at 10% O2), or sham stimulation. Their brains were examined using double immunohistochemical staining for orexin and c-Fos. The results indicated that IH (25.8±3.0%), but not SH (9.0±1.5%) activated orexin-containing neurons when compared to IO (5.5±0.6%) and sham stimulation (5.9±1.4%). These results correlate with those of our previous work showing that IH-induced respiratory long-term facilitation is dependent on orexin-containing neurons. Taken together, orexin contributes to repetitive hypoxia-induced respiratory activation and the hypoxic activation of orexin-containing neurons is pattern dependent.