Near-infrared spectroscopy during cardiopulmonary resuscitation and after restoration of spontaneous circulation: a valid technology?

Association between regional cerebral oxygen saturation and outcome of patients with out-of-hospital cardiac arrest: An observational study

Aim

This study aimed to evaluate the association between cerebral oxygen saturation (StO2) and return of spontaneous circulation (ROSC) in patients with out-of-hospital cardiac arrest (OHCA).

Methods

We retrospectively evaluated the data of patients with OHCA to determine the association between ROSC and various StO2 parameters (initial_StO2, final_StO2, mean_StO2, and Δ_StO2 [=final_StO2-initial_StO2]). Time-domain near-infrared spectroscopy was used to determine absolute StO2 values.

Results

Of the 108 patients with OHCA, 23 achieved ROSC. Although initial_StO2 values did not differ between the groups, final_StO2, mean_StO2, and Δ_StO2 were higher in the ROSC group than in the non-ROSC group. The cut-off values for initial_StO2, mean_StO2, and Δ_StO2 as predictors of ROSC were 35%, 30%, and 5%, respectively. The odds ratio for ROSC had markedly increased in the Δ_StO2 ≥ 5% subgroup (19.70 [6.06-64.11], p < 0.001). When the change in StO2 (=d_StO2) at 8 min from the initiation of StO2 measurement was assessed, the d_StO2 ≥ 5% subgroup had a higher odds ratio for ROSC than the d_StO2 < 5% subgroup (5.8 [1.78-18.85], p = 0.002), and this tendency was maintained until 20 min. In the evaluation using a two-by-two contingency table with initial_StO2 and Δ_StO2 as two parameters, 61.9% of the patients fell under the categories of initial_StO2 < 35% and Δ_StO2 < 5% and had the lowest rate of ROSC achievement (4.6%). In the Δ_StO2 ≥ 5% subgroup, approximately-two-thirds of the patients achieved ROSC irrespective of the initial_StO2 (initial_StO2 ≥ 35%, 66.7%; initial_StO2 < 35%, 60.0%).

Conclusions

Initial_StO2 and Δ_StO2 were associated with the achievement of ROSC.

Cerebral regional oxygen saturation during cardiopulmonary resuscitation and return of spontaneous circulation: A systematic review and meta-analysis

AIM

Predicting the return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation in victims of cardiac arrest (CA) remains challenging. Cerebral regional oxygen saturation (rSO2) measured during resuscitation is feasible, and higher initial and overall values seem associated with ROSC. However, these observations were limited to the analysis of few small single-centre studies. There is a growing number of studies evaluating the role of cerebral rSO2 in the prediction of ROSC.

METHODS

We conducted an updated meta-analysis aimed at investigating the association of initial and overall values of cerebral rSO2 with ROSC after CA. We performed subgroups analyses according to the location of CA and conducted a secondary analysis according to the country where the study was conducted (resuscitation practice varies greatly for out-of-hospital CA).

RESULTS

We included 17 studies. Higher initial rSO2 values (11 studies, n = 2870, 16.6% achieved ROSC) were associated with ROSC: Mean Difference (MD) -11.54 [95%Confidence Interval (CI)-20.96, -2.12]; p = 0.02 (I² = 97%). The secondary analysis confirmed this finding when pooling together European and USA studies, but did not for Japanese studies (p = 0.06). One multi-centre Japanese study was an outlier with large influence on 95%CI. Higher overall rSO2 values during resuscitation (9 studies, n = 894, 33.7% achieving ROSC) were associated with ROSC: MD-10.38; [-13.73, -7.03]; p < 0.00001 (I² = 77%). All studies were conducted in Europe/USA.

CONCLUSIONS

This updated meta-analysis confirmed the association between higher initial and overall values of cerebral rSO2 and ROSC after CA. However, we found geographical differences, since this association was not present when Japanese studies were analysed separately.

Near-Infrared Spectroscopy Assessments of Regional Cerebral Oxygen Saturation for the Prediction of Clinical Outcomes in Patients With Cardiac Arrest: A Review of Clinical Impact, Evolution, and Future Directions

Despite three decades of advancements in cardiopulmonary resuscitation (CPR) methods and post-resuscitation care, neurological prognosis remains poor among survivors of out-of-hospital cardiac arrest, and there are no reliable methods for predicting neurological outcomes in patients with cardiac arrest (CA). Adopting more effective methods of neurological monitoring may aid in improving neurological outcomes and optimizing therapeutic interventions for each patient. In the present review, we summarize the development, evolution, and potential application of near-infrared spectroscopy (NIRS) in adults with CA, highlighting the clinical relevance of NIRS brain monitoring as a predictive tool in both pre-hospital and in-hospital settings. Several clinical studies have reported an association between various NIRS oximetry measurements and CA outcomes, suggesting that NIRS monitoring can be integrated into standardized CPR protocols, which may improve outcomes among patients with CA. However, no studies have established acceptable regional cerebral oxygen saturation cut-off values for differentiating patient groups based on return of spontaneous circulation status and neurological outcomes. Furthermore, the point at which resuscitation efforts can be considered futile remains to be determined. Further large-scale randomized controlled trials are required to evaluate the impact of NIRS monitoring on survival and neurological recovery following CA.

Effects of therapeutic hypothermia on cerebral tissue oxygen saturation in a swine model of post-cardiac arrest

Since the introduction of therapeutic hypothermia (TH), trends have changed in the monitoring indicators used during and after cardiac arrest. During hypothermia, the cerebral metabolic rate of oxygen is reduced, which leads to uncertainty in regional cerebral tissue oxygen saturation (S_ctO₂). The aim of the present study was to evaluate the effect of TH on changes in S_ctO₂ using near-infrared spectroscopy. A total of 23 male domestic pigs were randomized into three groups: TH (n=9), normothermia (NT; n=9) and control (n=5). Animals in the control group underwent surgical preparation only. The animal models were established using 8 min of ventricular fibrillation and 5 min of cardiopulmonary resuscitation. In the TH group, at 5 min after resuscitation, the animals were cooled with a cooling blanket and ice packs for 24 h. S_ctO₂ was recorded throughout the experiment. In all groups, The mean arterial pressure, arterial carbon dioxide partial pressure, arterial oxygen partial pressure, lactate, neuron-specific enolase (NSE) and S100B were measured at baseline and at 1, 3, 6, 12, 24 and 30 h after resuscitation. S_ctO₂ significantly decreased after ventricular fibrillation, compared with the baseline. Following resuscitation, the S_ctO₂ values gradually increased to 55.6±3.8% of baseline in the TH group and 51.2±3.5% in the NT group (P=0.039). Significant differences between the two groups were observed, starting at 6 h after cardiac arrest. Throughout the hypothermic period, NSE and S100B showed an increasing trend, then decreased during rewarming in the TH and NT groups. NSE and S100B showed greater improvement in the TH group compared with the NT group at 6 and 24 h after resuscitation. Following cardiac arrest, therapeutic hypothermia could increase S_ctO₂ after resuscitation and could improve neurological outcome. In conclusion, S_ctO₂ may be a feasible marker for use in the early assessment of brain damage during and after cardiac arrest.

Electroencephalography and Brain Oxygenation Monitoring in the Perioperative Period

Maintaining brain function and integrity is a pivotal part of anesthesiological practice. The present overview aims to describe the current role of the 2 most frequently used monitoring methods for evaluation brain function in the perioperative period, ie, electroencephalography (EEG) and brain oxygenation monitoring. Available evidence suggests that EEG-derived parameters give additional information about depth of anesthesia for optimizing anesthetic titration. The effects on reduction of drug consumption or recovery time are heterogeneous, but most studies show a reduction of recovery times if anesthesia is titrated along processed EEG. It has been hypothesized that future EEG-derived indices will allow a better understanding of the neurophysiological principles of anesthetic-induced alteration of consciousness instead of the probabilistic approach most often used nowadays.Brain oxygenation can be either measured directly in brain parenchyma via a surgical burr hole, estimated from the venous outflow of the brain via a catheter in the jugular bulb, or assessed noninvasively by near-infrared spectroscopy. The latter method has increasingly been accepted clinically due to its ease of use and increasing evidence that near-infrared spectroscopy-derived cerebral oxygen saturation levels are associated with neurological and/or general perioperative complications and increased mortality. Furthermore, a goal-directed strategy aiming to avoid cerebral desaturations might help to reduce these complications. Recent evidence points out that this technology may additionally be used to assess autoregulation of cerebral blood flow and thereby help to titrate arterial blood pressure to the individual needs and for bedside diagnosis of disturbed autoregulation.