Changes in hemodynamic parameters and cerebral saturation during supraventricular tachycardia

Increase in regional cerebral saturation after elective electrical cardioversion of atrial fibrillation is only transient and without beneficial effects on neuropsychological functioning: cerebral saturation during electrical cardioversion

We aimed to confirm the positive association between a successful electrical cardioversion (ECV) and increase in SctO₂ and investigated whether this increase is persisting or not. Secondary, the influence of a successful ECV on the neuropsychological function and the association with SctO₂ was assessed as well. SctO₂ was measured continuously during elective ECV using near-infrared spectroscopy. Measurements started before induction of sedation and ended 15 min after awakening. A second measurement took place 4 to 6 weeks after ECV. To assess neuropsychological functioning, patients performed standardized neuropsychological tests before ECV and at follow-up and were compared to healthy volunteers as control group. SctO₂ was measured in 60 patients during elective ECV. ECV was successful in 50 AF patients, while in ten patients sinus rhythm was not obtained. SctO₂ increased immediately after successful ECV in 50 patients (1% (- 5 to 4); p = 0.031), but not after unsuccessful ECV in 10 patients (- 1% (- 5;3); p = 0.481). This SctO₂ change was positively correlated with the instant change in blood pressure (R² = 0.391; p = 0.004). At follow-up, SctO₂ values were no longer increased. Nevertheless, successful ECV improved the patient's quality of life but did not influence neuropsychological functioning at follow-up. A transient, instant SctO₂ increase was observed after successful ECV. This temporary increase in SctO₂ did not influence the neuropsychological functioning of the patients. Though, the quality of life of patients with a successful ECV improved.

Can the cerebral regional oxygen saturation be a perfusion parameter in shock?

INTRODUCTION

Shock, defined as a state of tissue hypoperfusion and the tissues reperfusion, is the main goal of management of shock. Increase in central venous saturation (CvSo₂) and decrease in blood lactate level are useful in assessment of adequacy of tissue perfusion. Near-infrared spectroscopy is a noninvasive way to observe real-time changes in regional cerebral saturation and has been used in patients with different brain diseases. There is a small body of literature suggesting that cerebral regional oxygen saturation (CrSo₂) monitoring added a value in assessment and management of intensive care unit (ICU) patients.

OBJECTIVES

The aim of this study was to determine if CrSo₂ can be used as an indicator of tissue perfusion in ICU patients with shock, and to determine the prognostic value of CrSo₂ in survival prediction.

METHODS

This is a prospective single-center pilot study entailed 20 patients who were diagnosed with shock admitted to adult ICU at King Fahd Military Medical Complex, Dhahran, Saudi Arabia. The CrSo₂ was monitored with near-infrared spectroscopy using Somatic, INVOS Oximeter 5100C (Covidien, Mansfield, Mass) with bilateral frontal electrode and mean value of the 2 readings was taken as well as blood lactate level, CvSo₂, mean arterial blood pressure, and cardiac index at baseline time, 8, 24, 48, and 72 hours. All patients with history of cerebrovascular diseases and those who presented with neurological deficits were excluded from the study.

RESULTS

Significant negative correlation was noticed between CrSo₂ and lactic acid at 8, 24, 48, and 72 hours from admission (r=-0.625, -0.711, -0.745, and -0.722, respectively; P=.003, .001, .001, and .001, respectively). Significant positive correlation was noticed between CrSo₂ and CvSo₂ at 8, 24, 48, and 72 hours from admission (r=0.572, 0.674, 0.527, and 0.757; P=.008, .001, .017, and .001, respectively). In addition, significant positive correlation was found between CrSo₂ and mean arterial pressure at 24, 48, and 72 hours from admission (r=0.523, 0.513, and 0.626, respectively; P=.018, .021, and .003, respectively). Significant difference was also detected between the value of CrSo₂ in the survivors (12 patients) and the nonsurvivors (8 patients) after 72 hours from admission, as it was 52.58%±7.33% and 44.75%±9.44% (P=.049), whereas it was not significantly different in the first 3 days.

CONCLUSIONS

Cerebral regional oxygen saturation might be helpful as one of the perfusion parameters in patients with shock and it could have a prognostic value in mortality prediction. However, further studies with larger sample size are still needed to validate these results.

Propofol effect on cerebral oxygenation in children with congenital heart disease

Propofol is a short-acting, intravenously administered hypnotic agent which is used in procedural sedation in children. Propofol is known to decrease systemic vascular resistance, arterial blood pressure and can lead to desaturations and decreased systemic perfusion in children with cardiac shunting. This may result in a reduction in cerebral blood flow and oxygenation. Near-infrared spectroscopy (NIRS) can monitor cerebral tissue oxygenation in the frontal neocortex. The objective of our study was to measure the changes in cerebral oxygen and blood supply after Propofol infusion in children with congenital heart disease. Propofol infusion may reduce cerebral oxygenation in children with congenital heart disease. The study group consisted of 32 children (f:m = 18:14), with median age of 49 (5-112) months and median weight of 15 (5-34) kg. We performed NIRS derived continuous measurement of cerebral oxygenation and cardiac output using Electrical velocimetry for 5 min before and after sedation with Propofol (1-2 mg/kg i.v.) for cardiac catheterization. Simultaneously, non-invasive arterial blood pressure and transcutaneous oxygen saturation were measured. Propofol sedation led to a significant decrease in mean arterial pressure (79 ± 16 vs. 67 ± 12 mmHg) (p = 0.01) and cardiac index (3.2 ± 0.8 vs. 2.9 ± 0.6 ml/min/m(2)) (p = 0.03). In contrast, cerebral tissue oxygenation index, increased significantly from 57 ± 11 to 59 ± 10 % (p < 0.05). Sedation with Propofol increased cerebral tissue oxygenation despite a decrease in cardiac index and arterial blood pressure. This may be caused by a decreased oxygen consumption of the sedated brain with intact cerebral auto-regulation.

Acute decrease of cerebral oxygen saturation during rapid ventricular and supraventricular rhythm: a pilot study

BACKGROUND

Monitoring of cerebral tissue oxygen saturation (SctO2 ) reflects cerebral microcirculation. We sought to characterize the decrease in SctO2 during supraventricular tachycardia (SVT) and ventricular tachycardia (VT) in adults.

METHODS

Twenty patients (mean age: 46.3 ± 18.1 years, 40% men) were included. Rapid atrial and ventricular pacing (200/min) was used as a model for VT and SVT. Near-infrared spectroscopy (NIRS) was used to measure SctO2 .

RESULTS

Atrial stimulation decreased right (P = 0.014) and left (P = 0.019) hemispheric SctO2 compared to baseline. Ventricular stimulation also decreased right (P < 0.001) and left (P < 0.001) hemispheric SctO2 . A negative correlation between age and minimal value under stimulation was found for atrial (right SctO2 r = -0.641, P = 0.034; left SctO2 r = -0.694, P = 0.018) and ventricular pacing (right SctO2 r = -0.564, P = 0.01; left SctO2 r = -0.604, P = 0.005). A positive correlation was found between left ventricular ejection fraction (LVEF) and minimal value under ventricular stimulation (right SctO2 r = 0.567, P = 0.009; left SctO2 r = 0.471, P = 0.036).

CONCLUSION

Cerebral perfusion decreased during simulated SVT and VT and is influenced by age and LVEF. Clinicians can consider NIRS monitoring in patients during ablation procedures and in critical care. NIRS may especially be appropriate for the elderly and for patients with impaired LVEF.

Noninvasive assessment of hemodynamic variables using near-infrared spectroscopy in patients experiencing cardiogenic shock and individuals undergoing venoarterial extracorporeal membrane oxygenation

PURPOSE

The relationship between near-infrared spectroscopy cerebral oximetry (CrSO2), peripheral oximetry (PrSO2) and hemodynamic variables is not fully understood.

METHODS

The relationship between CrSO2/PrSO2 and cardiac index (CI), systemic vascular resistance index (SVRI) and mean arterial pressure (MAP) in patients experiencing cardiogenic shock and those undergoing venoarterial extracorporeal membrane oxygenation (ECMO) was retrospectively analyzed; in patients on ECMO, total circulatory index (TCI) was calculated from the sum of CI and extracorporeal blood flow index.

RESULTS

In patients experiencing cardiogenic shock (n=10), significant correlations between PrSO2 values and CI (Spearman r=0.81; P<.0001), SVRI (r=-0.45; P<.0001), and MAP (r=0.58; P<.0001) were found. Significant correlations between CrSO2 and CI (r=0.55; P<.0001) and SVRI (r=-0.47; P<.0001), but not MAP, were observed. Linear regression analysis revealed that CI could be calculated using the following equation: CI=PrSO2/24.0. In patients on VA ECMO (n=12), significant correlations were found between PrSO2 and TCI (r=0.68; P<.0001), SVRI (r=-0.47; P<.0001), and MAP (r=0.27; P=.025). Significant correlations were also found between CrSO2 and TCI (r=0.68; P<.0001) and SVRI (r=-0.51; P<.0001), but not MAP.

CONCLUSIONS

Results of the present study suggest that CrSO2 and PrSO2 in particular can be used for noninvasive estimation and monitoring of global circulatory status in patients experiencing cardiogenic shock and individuals undergoing ECMO.

Improvement of cerebral oxygen saturation after successful electrical cardioversion of atrial fibrillation

AIMS

Cerebral and microvascular perfusion is reduced in atrial fibrillation (AF). Maintenance of brain perfusion is important in acute disease and long-term course. Assessment of brain perfusion and oxygenation is difficult in clinical practice. Our study aimed to determine changes in cerebral tissue oxygen saturation (SctO2) with bedside near-infrared spectroscopy (NIRS).

METHODS AND RESULTS

Twenty patients (mean age 67.7 ± 10.2 years, 50% men) in whom electrical cardioversion (CV) was successful were prospectively studied. Ten patients (mean age 64.2 ± 7.7 years, 80% men) in whom CV was not successful served as control group. Bilateral SctO2, mean arterial pressure (MAP), arterial oxygen saturation (SaO2), and heart rate were recorded and changes of all parameters before and after CV were compared between the groups. Our results show an increase in SctO2 after successful CV that was significantly higher compared with patients who remained in AF (right SctO2 3.25 ± 2.5 vs. -0.13 ± 0.52%, P = 0.001; left SctO2 4.27 ± 3.56 vs. -0.38 ± 2.4%, P < 0.001). Neither arterial blood pressure nor SaO2 changes differed significantly between the two groups. No correlation could be detected between the significant increase of SctO2 after successful CV and arterial blood pressure, SaO2, or heart rate.

CONCLUSION

Cerebral tissue oxygen saturation increases significantly after restoration of sinus rhythm. Near-infrared spectroscopy monitoring can identify changes of SctO2 after successful CV of AF independent from standard monitoring parameters (MAP, SaO2). Near-infrared spectroscopy can be used to detect cerebral oxygen saturation deficits in AF patients or patients at high risk for AF. Clinical applications may include monitoring during ablation procedures and in critical care.