Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2019
Letter Case ReportsLimitations of near infrared spectroscopy (NIRS) in neurosurgical setting: our case experience.
One of the primary goals of anaesthesia in neurosurgical procedures is prevention of cerebral hypoxia leading to secondary neurological injury. Cerebral oximetry detects periods of cerebral hypoxemia and allows intervention for prevention of secondary brain injury and its sequelae. This can be achieved by the use of Near Infrared Spectroscopy (NIRS). ⋯ In a neurosurgical setting, the erroneous values on the operative side could be attributed to altered tissue boundary conditions resulting in a changed optical path, which is normally held as a constant in NIRS measurements. The altered tissue boundary conditions could be due to the presence of air or blood between the myocutaneous flapskull, skull-dura, dura-brain interphases. It could also be that the sensors' penetrating depth was inadequate to compensate for the increased distance between sensor and brain tissue, thereby resulting in inaccurately higher values (> 80%).
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J Clin Monit Comput · Aug 2019
Mathematical arterialisation of peripheral venous blood gas for obtainment of arterial blood gas values: a methodological validation study in the clinical setting.
Arterial blood gas (ABG) analysis is an essential tool in the clinical assessment of acutely ill patients. Venous to arterial conversion (v-TAC), a mathematical method, has been developed recently to convert peripheral venous blood gas (VBG) values to arterialized VBG (aVBG) values. The aim of this study was to test the validity of aVBG compared to ABG in an emergency department (ED) setting. ⋯ Bland-Altman plot revealed clinically acceptable mean difference and limits-of-agreement intervals between ABG and aVBG pH and pCO2, but not between ABG and aVBG pO2. Arterialization of VBG using v-TAC is a valid method for measuring pH and pCO2, but not for pO2. Larger clinical studies are required to evaluate the applicability of v-TAC in different patient subpopulations.
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J Clin Monit Comput · Aug 2019
Post-extrasystolic characteristics in the arterial blood pressure waveform are associated with right ventricular dysfunction in intensive care patients.
Right ventricular dysfunction (RVD) is associated with end-organ dysfunction and mortality, but has been an overlooked condition in the ICU. We hypothesized that analysis of the arterial waveform in the presence of ventricular extrasystoles could differentiate patients with RVD from patients with a normally functioning right ventricle, because the 2nd and 3rd post-ectopic beat could reflect right ventricular state (pulmonary transit time) during the preceding ectopy. We retrospectively identified patients with echocardiographic evidence of moderate-to-severe RVD and patients with a normal functioning right ventricle (control) from the MIMIC database. ⋯ We identified 34 patients in the control group and 24 patients in the RVD group with ventricular extrasystoles. The mean SBP reduction at the 2nd and 3rd beat was lower in the RVD group compared with the control group [- 1.7 (SD: 1.9) % vs. - 3.6 (SD: 1.9) %, p < 0.001], and this characteristic differentiated RVD subjects from control subjects with an AUC of 0.76 (CI [0.64; 0.89]), with a specificity of 91% and sensitivity of 50%. In this proof-of-concept study, we found that post-extrasystolic ABP characteristics were associated with RVD.
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J Clin Monit Comput · Aug 2019
Can variable practice habits and injection port dead-volume put patients at risk?
Injection ports used to administer medications and draw blood samples have inherent dead-volume. This volume can potentially lead to inadvertent drug administration, contribute to erroneous laboratory values by dilution of blood samples, and increase the risk of vascular air embolism. We sought to characterize provider practice in management of intravenous (IV) and arterial lines and measure dead-volumes of various injection ports. ⋯ Mean (SD) dead-volume in microliters ranged from 0.1 (0.0) to 5.6 (1.0) in 1-way injection ports and from 54.1 (2.8) to 126.5 (8.3) in 4-way injection ports. The practices of our providers when giving medications and drawing blood samples are variable. The dead-volume associated with injection ports used at our institution may be clinically significant, increasing errors in medication delivery and laboratory analysis.