The Normobaric Oxygen Paradox-Hyperoxic Hypoxic Paradox: A Novel Expedient Strategy in Hematopoiesis Clinical Issues.

Hypoxia, even at non-lethal levels, is one of the most stressful events for all aerobic organisms as it significantly affects a wide spectrum of physiological functions and energy production. Aerobic organisms activate countless molecular responses directed to respond at cellular, tissue, organ, and whole-body levels to cope with oxygen shortage allowing survival, including enhanced neo-angiogenesis and systemic oxygen delivery. The benefits of hypoxia may be evoked without its detrimental consequences by exploiting the so-called normobaric oxygen paradox. The intermittent shift between hyperoxic-normoxic exposure, in addition to being safe and feasible, has been shown to enhance erythropoietin production and raise hemoglobin levels with numerous different potential applications in many fields of therapy as a new strategy for surgical preconditioning aimed at frail patients and prevention of postoperative anemia. This narrative review summarizes the physiological processes behind the proposed normobaric oxygen paradox, focusing on the latest scientific evidence and the potential applications for this strategy. Future possibilities for hyperoxic-normoxic exposure therapy include implementation as a synergistic strategy to improve a patient's pre-surgical condition, a stimulating treatment in critically ill patients, preconditioning of athletes during physical preparation, and, in combination with surgery and conventional chemotherapy, to improve patients' outcomes and quality of life.

Postoperative C-reactive protein kinetics predict postoperative complications in patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal carcinomatosis.

BACKGROUND: Relatively high morbidity rates are reported after cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). However, early predictors of complications after CRS plus HIPEC have not been identified. The aim of this study was to evaluate the predictive role of early postoperative serum C-reactive protein (CRP) level (Day 2-4) for the detection of post-operative complications. PATIENTS AND METHODS: We performed a retrospective study including 94 patients treated with complete CRS (R1) and HIPEC for PC from various primary origins (2011-2016). Post-operative complications were recorded. The values for postoperative inflammatory markers (white blood cells [WBC] and platelet counts, CRP) were compared between the different groups. RESULTS: CRP on post-operative days 2-4 was significantly higher in patients with than without complications (124 mg/L vs 46 mg/L; p < 0.0001) and higher in those with more major complications (162 mg/L vs 80 mg/L; p < 0.0012). WBC and platelet counts showed no difference within 5 days postoperatively. CONCLUSION: CRP levels, and kinetics mainly, between post-operative day 2 and 4, are decisive predictive markers of early and late post-operative complications after CRS plus HIPEC. The presence of post-operative complications should be suspected in patients with a high CRP mean, and a plateau level (days 2-4).

Perioperative Ketamine and Cancer Recurrence: A Comprehensive Review.

Cancer is a significant global health threat and a leading cause of death worldwide. Effective early-stage interventions, particularly surgery, can potentially cure many solid tumors. However, the risk of postoperative cancer recurrence remains high. Recent research highlights the influence of perioperative anesthetic and analgesic choices on the fate of residual cancer cells, potentially affecting recurrence risks. Among these agents, ketamine-a well-known anesthetic and analgesic-has garnered interest due to its antitumor properties, mainly through inhibiting the N-methyl-D-aspartate (NMDA) receptor found in various cancer tissues. Additionally, ketamine's potential immunomodulatory effects, given the expression of NMDA receptors on immune cells, suggest that it plays a significant role during the perioperative period. This review synthesizes current evidence on ketamine's impact on cancer cell biology, inflammation, immune modulation, and the role of the gut microbiota, proposing ketamine as a promising agent for enhancing oncological outcomes.

Physiological and Clinical Impact of Repeated Inhaled Oxygen Variation on Erythropoietin Levels in Patients After Surgery.

The "Normobaric Oxygen Paradox" (NOP) is a physiologic mechanism that induces an increase of endogenous erythropoietin (EPO) production by creating a state of relative hypoxia in subjects previously exposed to hyperoxia, followed by a rapid return to normoxia. Oxygen exposure duration and inspired oxygen fraction required to observe a significant increase in EPO or hemoglobin are not clearly defined. Consequently, we here study the effect of one model of relative hypoxia on EPO, reticulocytes and hemoglobin stimulation in patients after surgery. Patients were prospectively randomized in two groups. The O2 group (n = 10) received 100% oxygen for 1 h per day for eight consecutive days, via a non-rebreathing mask. The control group (n = 12) received no oxygen variation. Serum EPO, hemoglobin and reticulocyte count were measured on admission and postoperatively on days seven and nine. Percentage EPO at day nine with respect to the baseline value was significantly elevated within the groups [O2 group: 323.7 (SD ± 139.0); control group: 365.6 (SD± 162.0)] but not between them. No significant difference was found between the groups in terms of reticulocytes count and hemoglobin. Our NOP model showed no difference on EPO increase between the two groups. However, both groups expressed separately significant EPO elevation.

Perioperative volume replacement in children undergoing cardiac surgery: albumin versus hydroxyethyl starch 130/0.4.

OBJECTIVE: To compare 4% albumin with 6% hydroxyethyl starch (HES) 130/0.4 in terms of perioperative blood loss and intraoperative fluid requirements in children undergoing cardiac surgery. DESIGN: Prospective randomized study. SETTING: Single University Hospital. PATIENTS: Pediatric patients undergoing cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: One hundred nineteen children were randomized to receive up to 50 mL.kg of either 4% albumin (Alb: n = 59) or 6% HES 130/0.4 (HES: n = 60) for intraoperative fluid volume replacement including the cardiopulmonary bypass priming fluid. Ringer's lactate was used for further intraoperative volume needs. Monitoring, anesthetic, and surgical techniques were standardized. Packed red blood cells were administered according to a strict transfusion protocol. Intra- and postoperative blood loss were measured and also calculated from children's estimated blood volume, pre- and postoperative hematocrit, and volume of transfused packed red blood cells. MEASUREMENTS AND MAIN RESULTS: Volume of colloid used intraoperatively was similar in both groups (median [interquartiles]) (Alb: 50 [45-50] mL x kg; HES: 50 [37-50] mL x kg). Measured and calculated blood loss were not different between groups, but a higher number of children in the albumin group required allogeneic blood transfusion (78% vs. 57%; difference between proportions: 0.213; 95% confidence interval: 0.05-0.38; p = 0.0188). Intraoperative fluid balance was lower in the HES group (Alb 23 [11-39] mL x kg; HES: 12 [-5-30] mL x kg; p = 0.005). Postoperative outcome was not different between groups. CONCLUSIONS: In children undergoing cardiac surgery, 6% HES 130/0.4 may represent an interesting alternative to 4% albumin for intraoperative fluid volume replacement because of its lower cost.