Published in:
01-11-2010 | Original
Restoring arterial pressure with norepinephrine improves muscle tissue oxygenation assessed by near-infrared spectroscopy in severely hypotensive septic patients
Published in: Intensive Care Medicine | Issue 11/2010
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Purpose
To examine the consequences of administration of norepinephrine on muscle tissue oxygenation in severely hypotensive septic shock patients.
Methods
This was a prospective observational study conducted in a medical intensive care unit of a university hospital. We included 28 septic shock patients that received early volume resuscitation. All were eligible for receiving norepinephrine because of life-threatening hypotension and low diastolic arterial pressure. Muscle tissue oxygen saturation (StO2) and its changes during a vascular occlusion test were measured at the level of the thenar eminence using a near-infrared spectroscopy (NIRS) device. Transpulmonary thermodilution cardiac index (CI) and NIRS-derived variables were obtained before and after the mean arterial pressure (MAP) was increased by norepinephrine. The baseline StO2 and the vascular occlusion test-derived variables of 17 healthy volunteers were measured and served as controls.
Results
In healthy volunteers, StO2 ranged between 75 and 90% and StO2 recovery slopes ranged between 1.5 and 3.4%/s. Administration of norepinephrine, which was associated with an increase in MAP from 54 ± 8 to 77 ± 9 mmHg (p < 0.05), also induced increases in CI from 3.14 ± 1.03 to 3.61 ± 1.28 L/min/m2 (p < 0.05), in StO2 from 75 ± 9 to 78 ± 9% (p < 0.05) and in StO2 recovery slope from 1.0 ± 0.6 to 1.5 ± 0.7%/s (p < 0.05).
Conclusions
Norepinephrine administration aimed at achieving a MAP higher than 65 mmHg in septic shock patients with life-threatening hypotension resulted in improvement of NIRS variables measured at the level of the thenar eminence.