Alterations of tissue-dependent microcirculation in patients after successful resuscitation

Introduction

The crucial role of the microcirculation in improved neurological outcome in patients after successful resuscitation has been discussed for many years. New noninvasive imaging techniques enable the visualization and analysis of the microcirculation in vivo. Our study utilised an orthogonal polarization spectral (OPS) noninvasive imaging technique to test microcirculation in patients after successful resuscitation.

Methods

Between February and November 2008, 20 successfully resuscitated patients were investigated in the medical intensive care department of Albert Ludwigs University, Freiburg. OPS measurements were performed at the time of mild therapeutic hypothermia and after rewarming. These results were compared with the results of a control group that consists of 15 healthy people. OPS measurements were performed using the MicroScan from MicroVisionMedical. The recorded sublingual microcirculation images were analysed utilising the AVA software with a focus on the microcirculation parameters of total vessel density (TVD, mm/mm²) and perfused vessel density (PVD, mm/mm²).

Results

Patients after successful resuscitation showed a significant decrease in the tissue-dependent microcirculation compared with control (TVD: 5.33 ± 1.45 vs. 6.87 ± 1.07; P = 0.002) and PVD (3.48 ± 1.59 vs. 6.69 ± 1.03; P = 0.0002). Patients after successful resuscitation showed, during therapeutic hypothermia, a significant increased microcirculation (TVD and PVD) compared with the rewarmed phase (TVD: 6.41 ± 1.53 vs. 5.33 ± 1.45; P = 0.028; and PVD: 4.96 ± 2.3 vs. 3.48 ± 1.59; P = 0.023). These effects were independent of the use of catecholamines.

Conclusion

We could demonstrate significant alterations of the tissue-dependent microcirculation in patients after successful resuscitation. Patients in the post-resuscitation phase showed during therapeutic hypothermia an increased microcirculation, reflecting TVD and PVD, compared with the microcirculation after rewarming, independent of noradrenaline or dobutamine.