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Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study.

Dubin A, Pozo MO, Casabella CA, Pálizas F, Murias G, Moseinco MC, Kanoore Edul VS, Pálizas F, Estenssoro E, Ince C - Crit Care (2009)

Bottom Line: There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045).Nevertheless, there was a considerable interindividual variation.Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Servicio de Terapia Intensiva, Sanatorio Otamendi y Miroli, Buenos Aires C1115AAB, Argentina. arnaldodubin@speedy.com.ar

ABSTRACT

Introduction: Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation.

Methods: Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mechanically ventilated and required norepinephrine to maintain a mean arterial pressure (MAP) of 65 mmHg. We measured systemic hemodynamics, oxygen transport and consumption (DO2 and VO2), lactate, albumin-corrected anion gap, and gastric intramucosal-arterial PCO2 difference (DeltaPCO2). Sublingual microcirculation was evaluated by sidestream darkfield (SDF) imaging. After basal measurements at a MAP of 65 mmHg, norepinephrine was titrated to reach a MAP of 75 mmHg, and then to 85 mmHg. Data were analyzed using repeated measurements ANOVA and Dunnett test. Linear trends between the different variables and increasing levels of MAP were calculated.

Results: Increasing doses of norepinephrine reached the target values of MAP. The cardiac index, pulmonary pressures, systemic vascular resistance, and left and right ventricular stroke work indexes increased as norepinephrine infusion was augmented. Heart rate, DO2 and VO2, lactate, albumin-corrected anion gap, and DeltaPCO2 remained unchanged. There were no changes in sublingual capillary microvascular flow index (2.1 +/- 0.7, 2.2 +/- 0.7, 2.0 +/- 0.8) and the percent of perfused capillaries (72 +/- 26, 71 +/- 27, 67 +/- 32%) for MAP values of 65, 75, and 85 mmHg, respectively. There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045). In addition, the changes of perfused capillary density at increasing MAP were inversely correlated with the basal perfused capillary density (R2 = 0.95, P < 0.0001).

Conclusions: Patients with septic shock showed severe sublingual microcirculatory alterations that failed to improve with the increases in MAP with norepinephrine. Nevertheless, there was a considerable interindividual variation. Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patients.

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Relationship between the changes of perfused capillary density, when mean arterial pressure (MAP) was increased from the baseline to a MAP of 85 mmHg, with the basal perfused capillary density at a MAP of 65 mmHg.
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Figure 6: Relationship between the changes of perfused capillary density, when mean arterial pressure (MAP) was increased from the baseline to a MAP of 85 mmHg, with the basal perfused capillary density at a MAP of 65 mmHg.

Mentions: Although the total vascular density was not significantly altered, there was a trend to a decreased capillary density (ANOVA P = 0.09, linear trend P = 0.03; Table 4). The MFI and the percentage of perfused vessels were unchanged in the different types of vessels at increasing MAP values. The total perfused vascular density was unmodified for MAP values of 65, 75, and 85 mmHg (38 ± 14, 37 ± 15, 37 ± 4 vessels/mm2, respectively, ANOVA P = 0.94, linear trend P = 0.76); however, there was a trend to a decreased perfused capillary density (18 ± 10, 17 ± 10, 14 ± 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045). The heterogeneity flow index also remained unchanged (Table 4). The individual behaviour of capillary density, capillary MFI, percentage of perfused capillaries, perfused capillary density and capillary heterogeneity flow index are depicted in Figures 1 to 5. There was, however, considerable interindividual variability. In particular, there was a strong linear relationship between the changes of perfused capillary density, when MAP was increased from baseline to 85 mmHg, with the basal perfused capillary density at a MAP of 65 mmHg (Figure 6).


Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study.

Dubin A, Pozo MO, Casabella CA, Pálizas F, Murias G, Moseinco MC, Kanoore Edul VS, Pálizas F, Estenssoro E, Ince C - Crit Care (2009)

Relationship between the changes of perfused capillary density, when mean arterial pressure (MAP) was increased from the baseline to a MAP of 85 mmHg, with the basal perfused capillary density at a MAP of 65 mmHg.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2717464&req=5

Figure 6: Relationship between the changes of perfused capillary density, when mean arterial pressure (MAP) was increased from the baseline to a MAP of 85 mmHg, with the basal perfused capillary density at a MAP of 65 mmHg.
Mentions: Although the total vascular density was not significantly altered, there was a trend to a decreased capillary density (ANOVA P = 0.09, linear trend P = 0.03; Table 4). The MFI and the percentage of perfused vessels were unchanged in the different types of vessels at increasing MAP values. The total perfused vascular density was unmodified for MAP values of 65, 75, and 85 mmHg (38 ± 14, 37 ± 15, 37 ± 4 vessels/mm2, respectively, ANOVA P = 0.94, linear trend P = 0.76); however, there was a trend to a decreased perfused capillary density (18 ± 10, 17 ± 10, 14 ± 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045). The heterogeneity flow index also remained unchanged (Table 4). The individual behaviour of capillary density, capillary MFI, percentage of perfused capillaries, perfused capillary density and capillary heterogeneity flow index are depicted in Figures 1 to 5. There was, however, considerable interindividual variability. In particular, there was a strong linear relationship between the changes of perfused capillary density, when MAP was increased from baseline to 85 mmHg, with the basal perfused capillary density at a MAP of 65 mmHg (Figure 6).

Bottom Line: There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045).Nevertheless, there was a considerable interindividual variation.Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Servicio de Terapia Intensiva, Sanatorio Otamendi y Miroli, Buenos Aires C1115AAB, Argentina. arnaldodubin@speedy.com.ar

ABSTRACT

Introduction: Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation.

Methods: Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mechanically ventilated and required norepinephrine to maintain a mean arterial pressure (MAP) of 65 mmHg. We measured systemic hemodynamics, oxygen transport and consumption (DO2 and VO2), lactate, albumin-corrected anion gap, and gastric intramucosal-arterial PCO2 difference (DeltaPCO2). Sublingual microcirculation was evaluated by sidestream darkfield (SDF) imaging. After basal measurements at a MAP of 65 mmHg, norepinephrine was titrated to reach a MAP of 75 mmHg, and then to 85 mmHg. Data were analyzed using repeated measurements ANOVA and Dunnett test. Linear trends between the different variables and increasing levels of MAP were calculated.

Results: Increasing doses of norepinephrine reached the target values of MAP. The cardiac index, pulmonary pressures, systemic vascular resistance, and left and right ventricular stroke work indexes increased as norepinephrine infusion was augmented. Heart rate, DO2 and VO2, lactate, albumin-corrected anion gap, and DeltaPCO2 remained unchanged. There were no changes in sublingual capillary microvascular flow index (2.1 +/- 0.7, 2.2 +/- 0.7, 2.0 +/- 0.8) and the percent of perfused capillaries (72 +/- 26, 71 +/- 27, 67 +/- 32%) for MAP values of 65, 75, and 85 mmHg, respectively. There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045). In addition, the changes of perfused capillary density at increasing MAP were inversely correlated with the basal perfused capillary density (R2 = 0.95, P < 0.0001).

Conclusions: Patients with septic shock showed severe sublingual microcirculatory alterations that failed to improve with the increases in MAP with norepinephrine. Nevertheless, there was a considerable interindividual variation. Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patients.

Show MeSH
Related in: MedlinePlus