Shock Syndromes I

iv.

Although the study did not specifically evaluate the practice of transfusing blood in patients

with evidence of hypoperfusion (low Scvo2 or elevated lactate concentrations) associated with

a low hemoglobin concentration, the median Scvo2 at baseline was below 70% and lactate

concentrations were above 2 mmol/L in both groups, suggesting that most patients had

evidence of hypoperfusion.

These data suggest that use of a hemoglobin transfusion threshold of 7 g/dL or lower is safe for

most patients, including those with sepsis and septic shock.

section IV, Resuscitation Parameters and End Points, for an additional discussion of this topic.

Uncertainty persists regarding hemodynamic targets beyond the first 6 hours of presentation.

Therapy should be directed toward maintaining adequate end-organ perfusion and

normalization of lactate concentrations, but the specific method(s) to achieve these goals will

be patient-specific.

ii.

A strategy of systematically increasing CO to predefined “supranormal” values was not

associated with a mortality benefit; hence, it is not recommended.

Care should be used to avoid giving excessive fluids.

In a retrospective analysis of data from a randomized controlled trial of patients with septic

shock, patients in the highest quartile of fluid balance had a significantly higher mortality rate

than patients in the lowest two quartiles. This association was present when fluid balance was

evaluated at both 12 hours and 4 days after study enrollment. In the same analysis, a CVP

greater than 12 mm Hg conferred a higher risk of mortality than a lower CVP.

ii.

A meta-analysis of 9 randomized controlled trials (n=637) that compared interventions

targeted at limiting fluid administration in patients with sepsis found no difference in all-cause

mortality (RR 0.87; 95% CI, 0.69−1.10) or serious adverse effects (RR 0.91; 95% CI, 0.78−1.05)

with the use of lower versus higher fluid volumes.

iii.

Despite conflicting data between prospective (CLOVERS and CLASSIC) and retrospective

studies, fluid administration should only be given to patients who are proven or predicted to

respond to fluid. This is best accomplished using dynamic markers of fluid responsiveness.

Resuscitation targeted to improving microcirculatory perfusion is a potential new therapeutic

frontier.

Studies have shown that the microcirculation is often altered in patients with sepsis, persistent

microvascular alterations are associated with multisystem organ failure and death, alterations

are more severe in non-survivors than in survivors, and improvements in microcirculatory

blood flow correspond with improved patient outcomes.

ii.

Impaired microcirculatory perfusion may at least partly explain why patients have elevated

lactate concentrations despite achievement of (macrovascular) hemodynamic goals.

iii.

Several strategies to improve microcirculatory perfusion have been investigated.

but not late, sepsis. Another study found that microcirculatory perfusion improved with

PLR or fluid administration in patients who were fluid responsive.

correction of impaired microcirculatory perfusion.

nitroglycerin was not associated with improved microcirculatory blood flow. In-hospital

mortality was numerically higher in patients allocated to nitroglycerin than in placebo,

but this difference was not statistically significant (34.3% vs. 14.2%, p=0.09).

initiated after quantitative resuscitation (but within the first 48 hours of presentation).

Dobutamine significantly improved microcirculatory perfusion compared with baseline.

Of interest, the beneficial effects of dobutamine were unrelated to changes in cardiac

index or blood pressure.