Measuring cerebral oxygenation helps optimizing post-resuscitation therapy

Characteristics of regional cerebral oxygen saturation levels in patients with out-of-hospital cardiac arrest with or without return of spontaneous circulation: A prospective observational multicentre study

AIM

Our study aimed at filling the fundamental knowledge gap on the characteristics of regional brain oxygen saturation (rSO2) levels in out-of-hospital cardiac arrest (OHCA) patients with or without return of spontaneous circulation (ROSC) upon arrival at the hospital for estimating the quality of cardiopulmonary resuscitation and neurological prognostication in these patients.

METHODS

We enrolled 1921 OHCA patients from the Japan - Prediction of Neurological Outcomes in Patients Post-cardiac Arrest Registry and measured their rSO2 immediately upon arrival at the hospital by near-infrared spectroscopy using two independent forehead probes (right and left). We also assessed the percentage of patients with a good neurological outcome (defined as cerebral performance categories 1 or 2) 90 days post cardiac arrest.

RESULTS

After 90 days, 79 (4%) patients had good neurological outcomes and a median lower rSO2 level of 15% (15-20%). Compared to patients without ROSC upon arrival at the hospital, those with ROSC had significantly higher rSO2 levels (56% [39-65%] vs. 15% [15-17%], respectively; P<0.01), and significantly correlated right- and left-sided regional brain oxygen saturation levels (R=0.94 vs. 0.66, respectively). In both groups, the percentage of patients with a good 90-day neurological outcome increased significantly in proportion to their rSO2 levels upon arrival at the hospital (P<0.01).

CONCLUSION

Our data indicate that measuring rSO2 levels might be effective for both monitoring the quality of resuscitation and neurological prognostication in patients with OHCA.

[Near-infrared spectroscopy during cardiopulmonary resuscitation and mechanical circulatory support: From the operating room to the intensive care unit]

BACKGROUND

Near infrared spectroscopy (NIRS) allows continuous measurement of cerebral regional oxygen saturation (rSO2). It is a weighted saturation value derived from approximately 70-75 % venous, 20-25 % arterial and 2.5-5 % capillary blood. In contrast to pulse oximetry, NIRS is independent of pulsatile flow. Therefore, it is also applicable during extracorporeal circulation, cardiopulmonary resuscitation (CPR), and hypothermia.

OBJECTIVES

The purpose of this work is to describe the application of cerebral and somatic NIRS in cardiology and cardiac surgery patients in the operation room, during and after CPR, and during the intensive care unit stay.

MATERIALS AND METHODS

This article is based on peer-reviewed literature from PubMed.

RESULTS

Interventions based on decline of cerebral NIRS values during on-pump cardiac surgery can reduce major organ morbidity and mortality; however, the appearance of a postoperative cognitive dysfunction is scarcely influenced. Persisting of low cerebral oximetry values during resuscitation is a marker for not achieving return of spontaneous circulation under normothermia. NIRS is an additional method for monitoring that can be used during extracorporeal circulation.

CONCLUSION

NIRS is a rapidly available, user-friendly, and noninvasive method for continuous measurement of rSO2. NIRS provides additional information about tissue oxygenation especially during resuscitation and extracorporeal circulatory assist support. Recommendations concerning the use of NIRS for standard monitoring during resuscitation and mechanical circulatory support are not currently available. Further studies are required to show if use of NIRS can reduce pulse control and hands-off times during resuscitation and if use of NIRS can improve outcome after CPR and mechanical circulatory support.

Cerebral oximetry and cerebral blood flow monitoring in 2 pediatric survivors with out-of-hospital cardiac arrest

In pediatric out-of-hospital cardiac arrest (POHCA), cardiovascular monitoring tools have improved resuscitative endeavors and cardiovascular outcomes but with still poor neurologic outcomes. Regarding cardiac arrest in patients with congenital heart disease during surgery, the application of cerebral oximetry with blood volume index (BVI) during the resuscitation has shown significant results and prognostic significance. We present 2 POHCA patients who had cerebral oximetry with BVI monitoring during their arrest and postarrest phase in the emergency department and its potential prognostic aspect.Basic procedures include left and right cerebral oximetry with BVI monitoring at every 5-second interval during cardiac arrest, resuscitation, and postarrest in 2 POHCA patients in the pediatric emergency department.Regional cerebral tissue oxygen saturation (rSo2) with BVI readings in these 2 POHCA survivors demonstrated interesting cerebral physiology, blood flow, and potential prognostic outcome. In 1 patient, the reference range of cerebral rSo2 with positive blood flow during arrest and postarrest phases consistently occurred. This neurologic monitoring had its significance when the resuscitation effectiveness was used and end-tidal CO2 changes were lost. The other patient's cerebral rSo2 with simultaneous BVI readings and trending showed the effectiveness of the emergency medical services (EMS) resuscitation.Cerebral oximetry with cerebral blood flow index monitoring in these POHCA survivors demonstrates compelling periarrest and postarrest cerebral physiology information and prognostication. Cerebral oximetry with cerebral BVI monitoring during these arrest phases has potential as a neurologic monitor for the resuscitative intervention's effectiveness and its possible neurologic prognostic application in the pediatric OCHA patients.

Cerebral oximetry and cardiac arrest

Cerebral oximetry is a Food and Drug Administration-approved technology that allows monitoring of brain oxygen saturation in accessible superficial brain cortex regions, which are amongst the most vulnerable in regard to ischemic or hypoxic injury. Since most oxygen in the area of interest is located in the venous compartment, the determined regional brain oxygen saturation approximately reflects the local balance between oxygen delivery and oxygen consumption. Major systemic alterations in blood oxygen content and oxygen delivery will be accompanied by corresponding changes in regional brain saturation. This systematic review, which is based on a Medline search, focuses on the characteristic changes in regional cerebral oxygen saturation that occur, when global oxygen supply to the brain ceases. It further highlights the potential application of cerebral oximetry in the management of cardiac arrest victims, the predictability of clinical outcome after global cerebral ischemia, and it also indicates possible potentials for the management of cerebral reperfusion after having instituted return of spontaneous circulation.