Early Detection and Correction of Cerebral Desaturation With Noninvasive Oxy-Hemoglobin, Deoxy-Hemoglobin, and Total Hemoglobin in Cardiac Surgery: A Case Series.

Regional cerebral oxygen saturation (rS o2 ) obtained from near-infrared spectroscopy (NIRS) provides valuable information during cardiac surgery. The rS o2 is calculated from the proportion of oxygenated to total hemoglobin in the cerebral vasculature. Root O3 cerebral oximetry (Masimo) allows for individual identification of changes in total (ΔcHbi), oxygenated (Δ o2 Hbi), and deoxygenated (ΔHHbi) hemoglobin spectral absorptions. Variations in these parameters from baseline help identify the underlying mechanisms of cerebral desaturation. This case series represents the first preliminary description of Δ o2 Hbi, ΔHHbi, and ΔcHbi variations in 10 cardiac surgical settings. Hemoglobin spectral absorption changes can be classified according to 3 distinct variations of cerebral desaturation. Reduced cerebral oxygen content or increased cerebral metabolism without major blood flow changes is reflected by decreased Δ o2 Hbi, unchanged ΔcHbi, and increased ΔHHbi Reduced cerebral arterial blood flow is suggested by decreased Δ o2 Hbi and ΔcHbi, with variable ΔHHbi. Finally, acute cerebral congestion may be suspected with increased ΔHHbi and ΔcHbi with unchanged Δ o2 Hbi. Cerebral desaturation can also result from mixed mechanisms reflected by variable combination of those 3 patterns. Normal cerebral saturation can occur, where reduced cerebral oxygen content such as anemia is balanced by a reduction in cerebral oxygen consumption such as during hypothermia. A summative algorithm using rS o2 , Δ o2 Hbi, ΔHHbi, and ΔcHbi is proposed. Further explorations involving more patients should be performed to establish the potential role and limitations of monitoring hemoglobin spectral absorption signals.

Should we use diastolic function parameters to determine preload responsiveness in cardiac surgery? A pilot study.

BACKGROUND: Left ventricular (LV) diastolic function (DF) may play an important role in predicting fluid responsiveness. However, few studies assessed the role of diastolic function in predicting fluid responsiveness. The aim of this pilot study was to assess whether parameters of right and left diastolic function assessed with transesophageal echocardiography, including the mitral E/e' ratio, is associated with fluid responsiveness among patients undergoing elective bypass graft surgery. We also sought to compare other methods of fluid responsiveness assessment, including echocardiographic and hemodynamic parameters, pulse pressure variation, and stroke volume variation (SVV) (arterial pulse contour analysis, Flotrac/Vigileo system). RESULTS: We prospectively studied seventy patients undergoing coronary artery bypass grafting (CABG) monitored with a radial arterial catheter, transesophageal echocardiography (TEE), and a pulmonary artery catheter (for cardiac output measurements), before and after the administration of 500 mL of crystalloid over 10 min after the anesthetic induction. Thirteen patients were excluded (total of 57 patients). Fluid responsiveness was defined as an increase in cardiac index of ≥ 15%. There were 21 responders (36.8%) and 36 non-responders (63.2%). No difference in baseline pulsed wave Doppler echocardiographic measurements of any components of the mitral, tricuspid, and pulmonary and hepatic venous flows were found between responders and non-responders. There was no difference in MV tissue Doppler measurements between responders and non-responders, including E/e' ratio (8.7 ± 4.1 vs. 8.5 ± 2.8 in responders vs. non-responders, P = 0.85). SVV was the only independent variable to predict an increase in cardiac index by multivariate analysis (P = 0.0208, OR = 1.196, 95% CI (1.028-1.393)). CONCLUSIONS: In this pilot study, we found that no parameters of right and left ventricular diastolic function were associated with fluid responsiveness in patients undergoing CABG. SVV was the most useful parameter to predict fluid responsiveness. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02714244 . Registered 21 March 2016-retrospectively registered.

Ultrasound-guided transversus abdominis plane/genitofemoral blocks for a patient receiving extracorporeal life support.

Extracorporeal life support may be used in patients with refractory cardiogenic shock. The femoral venoarterial route can be used for implanting cannulae in patients who are hemodynamically unstable. Here we describe the use of an ultrasound-guided transversus abdominis plane block supplemented with the femoral component of the genitofemoral nerve as the anesthesia technique for peripheral cannulation of the femoral vessels in a patient with severe acute heart failure after myocardial infarction with ST-segment elevation. The procedure was performed using 40 mL of a 50:50 mixture of 0.5% levobupivacaine and 2% lidocaine (30 mL for transversus abdominis plane and 10 mL for genitofemoral block) associated with low-dose remifentanil infusion during spontaneous breathing. A left ventricular assist device was successfully implanted 4 days later.

Continuous controlled-infusion of hypertonic saline solution in traumatic brain-injured patients: a 9-year retrospective study.

INTRODUCTION: Description of a continuous hypertonic saline solution (HSS) infusion using a dose-adaptation of natremia in traumatic brain injured (TBI) patients with refractory intracranial hypertension (ICH). METHODS: We performed a single-center retrospective study in a surgical intensive care unit of a tertiary hospital. Fifty consecutive TBI patients with refractory ICH treated with continuous HSS infusion adapted to a target of natremia. In brief, a physician set a target of natremia adapted to the evolution of intracranial pressure (ICP). Flow of NaCl 20% was a priori calculated according to natriuresis, and the current and target natremia that were assessed every 4 hours. RESULTS: The HSS infusion was initiated for a duration of 7 (5 to 10) (8 ± 4) days. ICP decreased from 29 (26 to 34) (31 ± 9) mm Hg at H0 to 20 (15 to 26) (21 ± 8) mm Hg at H1 (P < 0.05). Cerebral perfusion pressure increased from 61 (50 to 70) (61 ± 13) mm Hg at H0 up to 67 (60 to 79) (69 ± 12) mm Hg at H1 (P < 0.05). No rebound of ICH was reported after stopping continuous HSS infusion. Natremia increased from 140 (138 to 143) (140 ± 4) at H0 up to 144 (141 to 148) (144 ± 4) mmol/L at H4 (P < 0.05). Plasma osmolarity increased from 275 (268 to 281) (279 ± 17) mmol/L at H0 up to 290 (284 to 307) (297 ± 17) mmol/L at H24 (P < 0.05). The main side effect observed was an increase in chloremia from 111 (107 to 119) (113 ± 8) mmol/L at H0 up to 121 (117 to 124) (121 ± 6) mmol/L at H24 (P < 0.05). Neither acute kidney injury nor pontine myelinolysis was recorded. CONCLUSIONS: Continuous HSS infusion adapted to close biologic monitoring enables long-lasting control of natremia in TBI patients along with a decreased ICP without any rebound on infusion discontinuation.