Monitoring trauma and intensive care unit resuscitation with tissue hemoglobin oxygen saturation

Abstract

Introduction: The purpose of the present review is to review our experience with near-infrared spectroscopy (NIRS) monitoring in shock resuscitation and predicting clinical outcomes.

Methods: The management of critically ill patients with goal-oriented intensive care unit (ICU) resuscitation continues to evolve as our understanding of the appropriate physiologic targets improves. It is now recognized that resuscitation to achieve supranormal indices is not beneficial in all patients and may precipitate abdominal compartment syndrome.

Results: Over the years, ICU technology has provided physicians with specific physiologic parameters to guide shock resuscitation. Throughout this time, the tissue hemoglobin oxygen saturation (StO2) monitor has emerged as a non-invasive means to obtain reliable physiologic parameters to guide clinicians' resuscitative efforts. StO2 monitors have been shown to aid in early identification of nonresponders and to predict outcomes in hemorrhagic shock and ICU resuscitation. These data have also been used to better understand and refine existing resuscitation protocols. More recently, use of NIRS technology to guide resuscitation in septic shock has been shown to predict outcomes in high-risk patients.

Conclusions: StO2 is an important tool in identifying high-risk patients in septic and hemorrhagic shock. It is a non-invasive means of obtaining vital information regarding outcome and adequacy of resuscitation.

Figure 1

Overview of the resuscitation protocol. ABG, arterial blood gas; art, arterial; BD, base deficit; CI, cardiac index; DO₂, oxygen delivery; Hb, hemoglobin; ICU, intensive care unit; LR, lactated Ringer's solution; NG, nasogastric; PA, pulmonary artery; PCWP, pulmonary wedge pressure; PRBC, packed red blood cells; PrCO₂, regional carbon dioxide tension measured by gastric tonometry. Reproduced with permission from [7].

Figure 2

Shock resuscitation variables during shock resuscitation (first 24 hours) and the following 12 hours. (a) Tissue hemoglobin oxygen saturation (StO₂), deltoid skeletal muscle and subcutaneous StO₂ saturation, monitored non-invasively using a prototype near-infrared spectrometer (Biospectrometer-NB Oximeter; Hutchinson Technology, Inc., Hutchinson, MN, USA). Do₂ I, systemic oxygen delivery index. (b) Mixed venous hemoglobin oxygen saturation (SvO₂) monitored invasively using a pulmonary artery catheter with fiberoptic oximetry capability. BD, base deficit; lactate, serum lactate concentration. Reproduced with permission from [8].

Figure 3

Physiologic parameters relative to multiple organ dysfunction syndrome and mortality. Receiver operating characteristic curves for physiologic parameters relative to (a) multiple organ dysfunction syndrome and (b) mortality within 1 hour of emergency department arrival. Skeletal muscle tissue hemoglobin saturation (StO₂) monitored non-invasively using a prototype near-infrared spectrometer (InSpectra Tissue Spectrometer; Hutchinson Technology, Inc., Hutchinson, MN, USA). BD, base deficit; SBP, systolic blood pressure. Reproduced with permission from [15].

Figure 4

Shock indices over the first 6 hours of hospitalization. G1, massive transfusion (MT) and dies in ≤24 hours; G2, MT and dies in >24 hours and/or multiple organ failure (MOF); G3, MT and survived without MOF. P-values reported for the group and hour from trauma center (TC) arrival factor and the interaction term. SBP, systolic blood pressure; StO₂, tissue hemoglobin oxygen saturation. Reproduced with permission from [26].