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Rom J Intern Med. 2005;43(1-2):73-8.

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Observations on peripheral microcirculation in young hypertensive patients.

Tudor A, Musat A, Bari M, Peta D, Cochior D.

"Titu Maiorescu" University, Faculty of Medicine, C.F.2 Hospital, Bucharest, Romania. japon52@yahoo.com

The increase of the peripheral blood flow resistance level is the major hemodynamic parameter in pathophysiology of essential hypertension (HT). The functional and morphological abnormalities of the microcirculation in the early stage, sometimes before the increase of the blood pressure, are intensely explored. Their identification is a proof for the genetical component of the hypertensive disease theory (studies on young male patients). Our purpose is to examine the capillary peripheral bed at the terminal phalanx level using in vivo capillary microscopy on a group of patients that have the risk of developing HT or that already have HT stage I (according to the JNC 7 Report). The nailfold area and the dorsal surface of the phalanx of fingers 3 and 4 were observed, having as a first objective the search for the areas with rare capillaries. Contrary to the data of the existing studies we have not found any case of significant capillary density decrease or of diffuse capillary rarefaction. Seven patients out of the total number of fifteen with HT stage I were identified to have a low vasomotility score. Considering the association of these cases with glucose intolerance (3 cases) and dyslipidemia (4 cases) the capillary functional anomaly could be related to precapillary arteriole modifications (endothelial dysfunction? metabolic status?).

PMID: 16739867 [PubMed - in process]

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Adv Exp Med Biol. 2005;566:269-75.

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The pathways of oxygen in brain. I. Delivery and metabolism of oxygen.

Gjedde A.

Flow-metabolism coupling in brain is different from flow-metabolism coupling in other vascular beds. In the classic description of Krogh, the capillary bed is a system of parallel tubes serving cylinders of tissue known as Krogh's cylinders. This simple arrangement yielded a quantitative expression of oxygen delivery to the tissue. However, in brain tissue, the arrangement is so disorderly that no prediction of oxygen tensions in the tissue is possible.

 

Only two claims of the capillary bed in the brain appear to be indisputable, i.e., the capillaries have a common arterial source and a common venous terminus, and their density is proportional to the average regional rates of metabolism at steady-state.

 

The following revision of the mechanism of flow-metabolism coupling in brain arose from the simple assumption, first introduced by Erwin R. Weibel in The Pathway for Oxygen, that every segment of the capillary bed "feeds" the same amount of brain tissue, i.e., that every fraction of the tissue is served by commensurate fractions of capillary density and oxygen diffusibility and accounts for the same fraction of the total oxygen consumption.

PMID: 16594162 [PubMed - indexed for MEDLINE]

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Definition of Reperfusion

Reperfusion: The restoration of blood flow to an organ or tissue. After a heart attack, an immediate goal is to quickly open blocked arteries and reperfuse the heart muscles. Early reperfusion minimizes the extent of heart muscle damage and preserves the pumping function of the heart.

Source

Nippon Ganka Gakkai Zasshi. 2005 Jul;109(7):428-33.

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[Effects of treatment for diabetic retinopathy on reperfusion of the capillary bed]

[Article in Japanese]

Sugiyama W, Ando N.

Department of Ophthalmology, Saiseikai Niigata Daini Hospital, Japan.

PURPOSE: We studied the effects of treatment for diabetic retinopathy on reperfusion and obstruction of the capillary bed. SUBJECT AND METHODS: In a retrospective study, we studied fluorescein angiograms of 66 patients (98 eyes) with diabetic retinopathy treated in our hospital between January 1998 and July 2002. Fluorescein angiography was performed at the first visit and each treatment (vitrectomy, photocoagulation, and follow-up). Angiographic findings of reperfusion and obstruction in the temporal raphe area were evaluated. RESULTS: In the patients who had undergone vitrectomy, reperfusion of the capillary bed was observed in 10 of 24 (42%) eyes and regularity or obstruction was observed in 14 (58%). In the patients treated by photocoagulation, reperfusion was observed in 11 of 56 (20%) eyes and regularity or obstruction was observed in 45 (80%). In the patients without treatment, reperfusion was observed in 1 of 18 (6 %) eyes and regularity or obstruction was observed in 17 (94%). CONCLUSION: Reperfusion of the capillary bed was significantly greater in the vitrectomy patients than in the photocoagulation and follow-up patients. Treatment for diabetic retinopathy influenced reperfusion and obstruction of the capillary bed in the temporal raphe area.

PMID: 16050461 [PubMed - indexed for MEDLINE]

Source

Adv Neonatal Care. 2005 Jun;5(3):147-54.

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Capillary refill time is an unreliable indicator of cardiovascular status in term neonates.

LeFlore JL, Engle WD.

University of Texas at Arlington, USA.

PURPOSE: Decisions regarding the need for volume replacement in neonates often are made in the immediate newborn period. Capillary refill time (CRT) is used as an indicator of circulatory status; however, recent data show that CRT varies considerably with age, ambient and skin temperature, anatomical site of measurement, and duration of pressure.

 

The purpose of this study was to (1) examine the relationship between CRT and heart rate (HR) and blood pressure (BP) in term neonates, and (2) evaluate the differences among CRT values measured at 3 body sites and with varying duration of cutaneous pressure.

 

DESIGN: This was a prospective, cross-sectional, correlational study. Subjects Forty-two appropriate-weight-for-gestational-age (AGA) neonates with birthweights, (M = 3407; SD = +/- 540 g), gestational ages (M = 39 weeks; SD = +/- 1 week), and sex (21 males, 21 females). Infants had no history of perinatal distress or maternal chorioamnionitis.

 

METHODS: Each neonate was studied prospectively 1 to 4 hours after birth. The infants were clothed with only a diaper and evaluated on a radiant warmer bed set to achieve an axillary temperature of 36.5 degrees to 37.0 degrees C.

 

Capillary refill time was measured with a digital stopwatch at 3 sites: volar surface of finger (F), plantar surface of heel (H), and lower sternum (St), using brief (1- to 2-second) and extended (3- to 4-second) pressure.

 

Heart rate was auscultated and counted for 60 seconds, and BP was measured by oscillometry.

 

Relationships among variables were assessed by Pearson correlation coefficient, analysis of variance, and multiple regression analysis. The Bonferroni correction for multiple comparisons was applied.

 

MAIN OUTCOME MEASURES: Capillary refill time, blood pressure, and heart rate.

 

PRINCIPAL RESULTS: There was no significant site variation for CRT for either brief (2.4 +/- 0.6 to 2.9 +/- 1.0 seconds) or extended (3.8 +/- 0.8 to 4.3 +/- 0.8 seconds) pressure. However, regardless of site, CRT was greater when extended versus brief pressure was used (P < 0.001). There were no significant correlations between HR and CRT. There was a moderate, direct relationship between BP and CRT observed in the following anatomic sites: (1) sternum/extended pressure and systolic BP (SBP), diastolic BP, and mean BP (r = 0.35, P = 0.02; r = 0.49, P = 0.001; and r = 0.43, P = 0.005, respectively); (2) sternum/brief pressure and SBP (r = 0.31, P = 0.05); and (3) finger/extended pressure and SBP (r = 0.30, P = 0.05).

 

CONCLUSIONS: An unanticipated moderate, direct correlation between BP and CRT was observed; prolongation of CRT occurred with elevated blood pressure. This finding may have been secondary to increased circulating vasoactive substances in the newborn period; measurement of these substances was beyond the scope of this study. In addition, CRT was highly dependent on the duration of cutaneous pressure, regardless of the site. These 2 findings indicate that CRT may be an unreliable indicator of cardiovascular status in the term neonate during the first 4 hours after birth.

PMID: 16034737 [PubMed - indexed for MEDLINE]

Source

JAMA. 2004 Jun 9;291(22):2746-54.

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Comment in:

• Evid Based Nurs. 2005 Apr;8(2):57.

Is this child dehydrated?

Steiner MJ, DeWalt DA, Byerley JS.

Department of Pediatrics, University of North Carolina School of Medicine, and Robert Wood Johnson Clinical Scholars Program, Chapel Hill 27599-7593, USA.

CONTEXT: The ability to assess the degree of dehydration quickly and accurately in infants and young children often determines patient treatment and disposition. OBJECTIVE: To systematically review the precision and accuracy of symptoms, signs, and basic laboratory tests for evaluating dehydration in infants and children. DATA SOURCES: We identified 1561 potential articles by multiple search strategies of the MEDLINE database through PubMed. Searches of bibliographies of retrieved articles, the Cochrane Library, textbooks, and private collections of experts in the field yielded an additional 42 articles. STUDY SELECTION: Twenty-six of 1603 reviewed studies contained original data on the precision or accuracy of findings for the diagnosis of dehydration in young children (1 month to 5 years). DATA EXTRACTION: Two of the 3 authors independently reviewed and abstracted data for estimating the likelihood ratios (LRs) of diagnostic tests. We eliminated 13 of the 26 studies because of the lack of an accepted diagnostic standard or other limitation in study design. The other 13 studies were included in the review. DATA SYNTHESIS: The most useful individual signs for predicting 5% dehydration in children are an abnormal capillary refill time (LR, 4.1; 95% confidence interval [CI], 1.7-9.8), abnormal skin turgor (LR, 2.5; 95% CI, 1.5-4.2), and abnormal respiratory pattern (LR, 2.0; 95% CI, 1.5-2.7). Combinations of examination signs perform markedly better than any individual sign in predicting dehydration. Historical points and laboratory tests have only modest utility for assessing dehydration.

 

CONCLUSIONS: The initial assessment of dehydration in young children should focus on estimating capillary refill time, skin turgor, and respiratory pattern and using combinations of other signs.

 

The relative imprecision and inaccuracy of available tests limit the ability of clinicians to estimate the exact degree of dehydration.

Publication Types:

• Review

PMID: 15187057 [PubMed - indexed for MEDLINE]

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