Monitoring Tissue Perfusion in Critically Ill or High-risk Surgical Patients

Overview

Circulatory shock is defined as an imbalance between oxygen supply and/or impaired oxygen use to maintain organ function. With growing evidence of lack of correlation between macro- and micro-circulation, use of "Whole Body" markers such as blood pressure (BP) or Lactates are often insufficient to assess the severity of the oxygen debt and/or tissue hypoperfusion. Thus, an approach incorporating tissue-perfusion based endpoints would represent a significant step up to guide optimal resuscitation of critically-ill patients and to reduce complications in high-risk surgery. Current monitoring techniques, that complement systemic hemodynamics by focusing on regional perfusion, still lack the required user-friendliness and/or clinical relevance to be routinely used at bedside. Therefore, assessment of the adequacy of tissue perfusion and oxygenation is suboptimal, and implementation of the above-mentioned approaches of resuscitation is still a challenge. Urethral perfusion is likely to be early and significantly impaired during low-flow states and thus represents a good "candidate" as a surrogate site to assess the perfusion of visceral organs. Besides, urethral mucosa can be investigated in a less invasive and simpler manner than "deeper" organs. Nowadays, no practical methods or devices are available to monitor perfusion in the pelvic area. Thus, recent development of a new monitoring device of urethral perfusion could fill this need and enable enhanced management of patients in Intensive Care Units (ICU) and Operating Rooms (OR). The device consists of a modified Foley catheter equipped with a photoplethysmographic sensor: the IKORUS UP probe. The probe will be used by intensivists or anesthesiologists on high-risk surgical patients, i.e. patients with comorbidities undergoing major vascular, thoracic and/or abdominal surgery.