Faculty Bibliography

PURPOSE OF REVIEW: Monitoring of the peripheral circulation can be done noninvasively in contrast to the more traditional invasive systemic haemodynamic monitoring in the intensive care unit. Physical examination of peripheral circulation based on clinical assessment has been well emphasized for its convenience, accessibility, and relation to the prognosis of patients with circulatory shock. The purpose of this article is to highlight the main findings according to recent literature into the clinical applications of the peripheral perfusion assessment in patient management. RECENT FINDINGS: Clinical assessment of peripheral circulation includes physical examination by inspecting the skin for pallor or mottling, and measuring capillary refill time on finger or knee. Studies have addressed the capillary refill time assessment in adults and its relation to normal range, body site, effect of skin temperature, and its reliability among examiners. These are easily applicable methods in many circumstances, and it has been used for predicting unfavourable outcomes in critically ill adult patients. Current studies are ongoing to determine the effects of different interventions on the clinical parameters of peripheral circulation in critically ill patients during shock resuscitation. SUMMARY: The feasibility and reproducibility of the clinical assessment of peripheral circulation are substantial, and reliance on capillary refill time, skin temperature, and mottling score must be emphasized and exploited. Incorporating therapeutic strategies into resuscitation protocols that aim at normalizing these peripheral circulation parameters are being developed to investigate the impact of peripheral perfusion-targeted resuscitation in the survival of critically ill patients.

Hepatosplanchnic circulation receives almost half of cardiac output and is essential to physiologic homeostasis. Liver cirrhosis is estimated to affect up to 1% of populations worldwide, including 1.5% to 3.3% of intensive care unit patients. Cirrhosis leads to hepatosplanchnic circulatory abnormalities and end-organ damage. Sepsis and cirrhosis result in similar circulatory changes and resultant multi-organ dysfunction. This review provides an overview of the hepatosplanchnic circulation in the healthy state and in cirrhosis, examines the signaling pathways that may play a role in the physiology of cirrhosis, discusses the physiology common to cirrhosis and sepsis, and reviews important issues in management.

Fluid therapy after initial resuscitation in critically ill, septic patients may lead to harmful overloading and should therefore be guided by indicators of an increase in stroke volume (SV), i.e. fluid responsiveness. Our objective was to investigate whether tissue perfusion and oxygenation are able to monitor fluid responsiveness, even after initial resuscitation. Thirty-five critically ill, septic patients underwent infusion of 250 mL of colloids, after initial fluid resuscitation. Prior to and after fluid infusion, SV, cardiac output sublingual microcirculatory perfusion (SDF: sidestream dark field imaging) and skin perfusion and oxygenation (laser Doppler flowmetry and reflectance spectroscopy) were measured. Fluid responsiveness was defined by a >/=5 or 10% increase in SV upon fluids. In responders to fluids, SDF-derived microcirculatory and skin perfusion and oxygenation increased, but only the increase in cardiac output, mean arterial and pulse pressure, microvascular flow index and relative Hb concentration and oxygen saturation were able to monitor a SV increase. Our proof of principle study demonstrates that non-invasively assessed tissue perfusion and oxygenation is not inferior to invasive hemodynamic measurements in monitoring fluid responsiveness. However skin reflectance spectroscopy may be more helpful than sublingual SDF.

OBJECTIVES: Microcirculatory alterations are associated with adverse outcome in subsets of critically ill patients. The prevalence and significance of microcirculatory alterations in the general ICU population are unknown. We studied the prevalence of microcirculatory alterations in a heterogeneous ICU population and its predictive value in an integrative model of macro- and microcirculatory variables. DESIGN: Multicenter observational point prevalence study. SETTING: The Microcirculatory Shock Occurrence in Acutely ill Patients study was conducted in 36 ICUs worldwide. PATIENTS: A heterogeneous ICU population consisting of 501 patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Demographic, hemodynamic, and laboratory data were collected in all ICU patients who were 18 years old or older. Sublingual Sidestream Dark Field imaging was performed to determine the prevalence of an abnormal capillary microvascular flow index (< 2.6) and its additional value in predicting hospital mortality. In 501 patients with a median Acute Physiology and Chronic Health Evaluation II score of 15 (10-21), a Sequential Organ Failure Assessment score of 5 (2-8), and a hospital mortality of 28.4%, 17% exhibited an abnormal capillary microvascular flow index. Tachycardia (heart rate > 90 beats/min) (odds ratio, 2.71; 95% CI, 1.67-4.39; p < 0.001), mean arterial pressure (odds ratio, 0.979; 95% CI, 0.963-0.996; p = 0.013), vasopressor use (odds ratio, 1.84; 95% CI, 1.11-3.07; p = 0.019), and lactate level more than 1.5 mEq/L (odds ratio, 2.15; 95% CI, 1.28-3.62; p = 0.004) were independent risk factors for hospital mortality, but not abnormal microvascular flow index. In reference to microvascular flow index, a significant interaction was observed with tachycardia. In patients with tachycardia, the presence of an abnormal microvascular flow index was an independent, additive predictor for in-hospital mortality (odds ratio, 3.24; 95% CI, 1.30-8.06; p = 0.011). This was not true for nontachycardic patients nor for the total group of patients. CONCLUSIONS: In a heterogeneous ICU population, an abnormal microvascular flow index was present in 17% of patients. This was not associated with mortality. However, in patients with tachycardia, an abnormal microvascular flow index was independently associated with an increased risk of hospital death.

BACKGROUND: The aim of the present study was to test the potential protective effects of the organic vanadium salt bis (maltolato) oxovanadium (BMOV; 15 mg/kg) in the context of renal ischemia/reperfusion (30 min of ischemia) and its effects on renal oxygenation and renal function in the acute phase of reperfusion (up to 90 min post-ischemia). METHODS: Ischemia was established in anesthetized and mechanically ventilated male Wistar rats by renal artery clamping. Renal microvascular and venous oxygenation were measured using phosphorimetry. Creatinine clearance rate, sodium reabsorption, and renal oxygen handling efficiency were considered markers for renal function. RESULTS: The main findings were that BMOV did not affect the systemic and renal hemodynamic and oxygenation variables and partially protected renal sodium reabsorption. CONCLUSIONS: Pretreatment with the organic vanadium compound BMOV did not protect the kidney from I/R injury.