Journal of clinical monitoring and computing
-
J Clin Monit Comput · Aug 2015
Observational StudyProspective evaluation of regional oxygen saturation to estimate central venous saturation in sepsis.
Current treatment guidelines for sepsis claim an early goal-directed hemodynamic optimization including fluid resuscitation, use of vasopressors and inotropic agents. We investigated the correlation between the prominent treatment goal central venous saturation (ScvO2) and the frontal and the thenar regional oxygen saturation (rSO2) measured by near infrared spectroscopy. Secondary, we examined the value of ScvO2, lactate levels and rSO2 as surrogate markers of an impaired tissue oxygenation for outcome prediction in sepsis. ⋯ In the group with ScvO2 <70% and lactate levels <2.5 mmol/l no patients died during the observation period. Frontal rSO2 correlates with ScvO2 but both frontal and thenar rSO2 do not exactly discriminate between patients with high or low ScvO2 in sepsis. The combination of elevated lactate >2.5 mmol/l and ScvO2 >70 % is highly associated with poor outcome in ICU patients with sepsis, severe sepsis and septic shock.
-
J Clin Monit Comput · Aug 2015
Pulse transit time shows vascular changes caused by propofol in children.
Pulse transit time (PTT) is the time that it takes for the arterial pulse pressure wave to travel from the aortic valve to the periphery. It is a simple noninvasive technique for evaluating vascular changes. This study investigated the vascular changes by propofol during the induction of anesthesia in pediatric patients with the measuring of PTT. ⋯ The PTT after the peak changed variously; most of the patients showed no plateau; the PTT decreased progressively after the peak. The PTT after propofol administration prolonged in short time and rapidly recovered toward to the baseline values in pediatric patients. In conclusion, the baseline PTT in children is shorter comparing with adults and the vasodilatory effect of propofol on the vessels as described by the PTT was rapid and the recovery was faster, although the response to propofol was more varied than in adults.
-
J Clin Monit Comput · Aug 2015
Hypoxic guard systems do not prevent rapid hypoxic inspired mixture formation.
Because a case report and theoretical mass balances suggested that hypoxic guard systems may not prevent the formation of hypoxic inspired mixtures (FIO2 ≤ 21 %) over the clinically used fresh gas flow (FGF) range, we measured FIO2 over a wide range of hypoxic guard limits for O2/N2O and O2/air mixtures. After IRB approval, 16 ASA I-II patients received sevoflurane in either O2/N2O (n = 8) or O2/air (n = 8) using a Zeus(®) anesthesia machine in the conventional mode. After using an 8 L/min FGF with FDO2 = 25% for 10 min, the following hypoxic guard limits were tested for 4 min each, expressed as [total FGF in L/min; FDO2 in %]: [0.3;85], [0.4;65], [0.5;50], [0.7;36], [0.85;30], [1.0;25], [1.25;25], [1.5;25], [2;25], [3;25], [5;25], and [8;25]. ⋯ In all 1, 1.25, and 1.5 L/min FGF groups, FIO2 decreased below 21% in all but one patient; this occurred within 1 min in at least one patient. In the 0.7 L/min O2/air group and the 3 L/min late O2/N2O and O2/air groups, FIO2 decreased below 21% in one patient. Current hypoxic guard systems do not reliably prevent a hypoxic FIO2 with O2/N2O and O2/air mixtures, particularly between 0.7 and 3 L/min.
-
J Clin Monit Comput · Aug 2015
Observational StudyReliability of a new 4th generation FloTrac algorithm to track cardiac output changes in patients receiving phenylephrine.
Phenylephrine is often used to treat intra-operative hypotension. Previous studies have shown that the FloTrac cardiac monitor may overestimate cardiac output (CO) changes following phenylephrine administration. A new algorithm (4th generation) has been developed to improve performance in this setting. ⋯ Agreement between FloTrac G3 and Nexfin was: 0.23 ± 1.19 l/min and concordance was 51.1%. In contrast, agreement between FloTrac G4 and Nexfin was: 0.19 ± 0.86 l/min and concordance was 87.2%. In conclusion, the pulse contour method of measuring CO, as implemented in FloTrac 4th generation algorithm, has significantly improved its ability to track the changes in CO induced by phenylephrine.