Faculty Bibliography

BACKGROUND: Persistent hyperlactatemia during septic shock is multifactorial. Hypoperfusion-related anaerobic production and adrenergic-driven aerobic generation together with impaired lactate clearance have been implicated. An excessive adrenergic response could contribute to persistent hyperlactatemia and adrenergic modulation might be beneficial. We assessed the effects of dexmedetomidine and esmolol on hemodynamics, lactate generation, and exogenous lactate clearance during endotoxin-induced septic shock. METHODS: Eighteen anesthetized and mechanically ventilated sheep were subjected to a multimodal hemodynamic/perfusion assessment including hepatic and portal vein catheterizations, total hepatic blood flow, and muscle microdialysis. After monitoring, all received a bolus and continuous infusion of endotoxin. After 1 h they were volume resuscitated, and then randomized to endotoxin-control, endotoxin-dexmedetomidine (sequential doses of 0.5 and 1.0 mug/k/h) or endotoxin-esmolol (titrated to decrease basal heart rate by 20 %) groups. Samples were taken at four time points, and exogenous lactate clearance using an intravenous administration of sodium L-lactate (1 mmol/kg) was performed at the end of the experiments. RESULTS: Dexmedetomidine and esmolol were hemodynamically well tolerated. The dexmedetomidine group exhibited lower epinephrine levels, but no difference in muscle lactate. Despite progressive hypotension in all groups, both dexmedetomidine and esmolol were associated with lower arterial and portal vein lactate levels. Exogenous lactate clearance was significantly higher in the dexmedetomidine and esmolol groups. CONCLUSIONS: Dexmedetomidine and esmolol were associated with lower arterial and portal lactate levels, and less impairment of exogenous lactate clearance in a model of septic shock. The use of dexmedetomidine and esmolol appears to be associated with beneficial effects on gut lactate generation and lactate clearance and exhibits no negative impact on systemic hemodynamics.

BACKGROUND: Wernicke encephalopathy can have different clinical outcomes. Although infections may precipitate the encephalopathy itself, it is unknown whether infections also modify the long-term outcome in patients developing Korsakoff syndrome. OBJECTIVE: To determine whether markers of infection, such as white blood cell (WBC) counts and absolute neutrophil counts in the Wernicke phase, are associated with cognitive outcomes in the end-stage Korsakoff syndrome. METHOD: Retrospective, descriptive study of patients admitted to Slingedael Korsakoff Center, Rotterdam, The Netherlands. Hospital discharge letters of patients with Wernicke encephalopathy were searched for relevant data on infections present upon hospital admission. Patients were selected for further analysis if data were available on WBC counts in the Wernicke phase and at least 1 of 6 predefined neuropsychological tests on follow-up. RESULTS: Infections were reported in 35 of 68 patients during the acute phase of Wernicke-Korsakoff syndrome-meningitis (1), pneumonia (14), urinary tract infections (9), acute abdominal infections (4), sepsis (5) empyema, (1) and infection "of unknown origin" (4). The neuropsychological test results showed significant lower scores on the Cambridge Cognitive Examination nonmemory section with increasing white blood cell counts (Spearman rank correlation, rho = -0.34; 95% CI: -0.57 to -0.06; 44 patients) and on the "key search test" of the behavioral assessment of the dysexecutive syndrome with increasing absolute neutrophil counts (rho= -0.85; 95% CI: -0.97 to -0.42; 9 patients). CONCLUSIONS: Infections may be the presenting manifestation of thiamine deficiency. Patients with Wernicke-Korsakoff syndrome who suffered from an infection during the acute phase are at risk of worse neuropsychological outcomes on follow-up.

PURPOSE: To correlate clinical indicators of peripheral perfusion with visceral organ vascular tone in 30 septic shock patients. MATERIALS AND METHODS: In a prospective pilot study, capillary refill time, the Mottling score, and peripheral temperature were determined within 24, 48, and 72 hours after intensive care unit admission. Simultaneously, pulsatility indices in the liver, spleen, kidneys, and intestines were measured by Doppler ultrasonography. Correlation analyses were calculated, applying an adjusted significance level (P< .0125) to correct for multiple testing. RESULTS: Significant relationships were observed between the pulsatility index of selected organs and the capillary refill time (intestines: r= 0.325, P= .007), and the Mottling score (kidneys: r= 0.396, P= .006), but not peripheral temperature (all r< 0.14, P> .05). An association over time was observed for the capillary refill time and pulsatility index of the liver (P= .04) and intestines (P= .03) as well as for the Mottling score and the kidneys' pulsatility index (P= .03), but not for peripheral temperature and any visceral organs' pulsatility index. CONCLUSIONS: Capillary refill time and skin mottling may be correlated with the pulsatility index, a sonographic surrogate of vascular tone, of visceral organs in early septic shock.

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.