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.

Clinical and Technical Limitations of Cerebral and Somatic Near-Infrared Spectroscopy as an Oxygenation Monitor.

Cerebral and somatic near-infrared spectroscopy monitors are commonly used to detect tissue oxygenation in various circumstances. This form of monitoring is based on tissue infrared absorption and can be influenced by several physiological and non-physiological factors that can induce error in the interpretation. This narrative review explores those clinical and technical limitations and proposes solutions and alternatives in order to avoid some of those pitfalls.

Oral Spirulina Platensis Attenuates Hyperglycemia and Exhibits Antinociceptive Effect in Streptozotocin-Induced Diabetic Neuropathy Rat Model.

INTRODUCTION: Diabetic neuropathy is a common consequence of diabetes. Hyperalgesia is one of the main symptoms of diabetic neuropathy. In response to noxious stimuli, streptozotocin (STZ)-induced diabetic rats show exaggerated hyperalgesic behavior, while Spirulina platensis has anti-inflammatory, antioxidant, and insulin-like effects. To assess the antinociceptive effect of oral Spirulina platensis (SP) powder on formalin-induced nociceptive responses in STZ-induced diabetic rats. METHODS: Sixty mature male albino rats were randomly allocated into six equal groups (10 in each group). Group 1 (control non-diabetic group) received 0.9% saline; group 2 was given oral pure SP powder-treated as a non-diabetic control group, group 3 was sodium salicylate-treated rats and used as a positive non-diabetic control group, group 4 managed as vehicle-treated diabetic rats, group 5 considered as SP-treated-diabetic group, and sodium salicylate-treated-diabetic rats used as a diabetic positive control group (group 6). STZ-diabetic rats were orally given SP in a dose of 500 mg kg/day for 1 month. The formalin test was implemented in two phases: the early phase in the first 10-min post-formalin injection, and the late phase was considered in the 15-60 min post-formalin injection time interval. RESULTS: Pain scores were increased in the diabetic groups during both phases of the experiment. Blood glucose was significantly reduced in diabetic rats that received oral SP, P < 0.01. Besides, SP-treated rats had lower pain scores during both phases of the experiment than untreated diabetic ones. However, in the sodium salicylate group, the pain score was reduced only during the second phase. An exaggerated nociceptive response occurred in diabetic rats after the formalin test. A significant antinociceptive effect appeared in SP-treated control and diabetic rats. DISCUSSION: The findings suggest that oral Spirulina platensis could have a potential therapeutic role for managing induced painful diabetic neuropathy in rats.

A Practical Approach to Cerebro-Somatic Near-Infrared Spectroscopy and Whole-Body Ultrasound.

Near-infrared spectroscopy (NIRS) is an emerging noninvasive monitoring modality based on chromophore absorption of infrared light. Because NIRS provides instantaneous information on cerebral and somatic tissue oxygenation, it becomes mandatory to identify rapidly the etiology of impaired regional oxygenation and thus perfusion. To do so, the use of whole-body ultrasound (WHOBUS) represents a significant advance in the management of patients experiencing cerebral or somatic desaturation. This narrative review describes the authors' experience since 2002 in the use of combined NIRS and WHOBUS. A practical approach in the use of both modalities and their respective limitations is described.