Cerebral oxygenation saturation in childhood: difference by age and comparison of two cerebral oximetry algorithms.

Few reports are available on the monitoring of regional cerebral oxygen saturation (rSO2) in pediatric patients undergoing non-cardiac surgical procedures. In addition, no study has examined the rSO2 levels in children of a broad age range. In this study, we aimed to assess and compare rSO2 levels in pediatric patients of different age groups undergoing non-cardiac surgery. We used two oximeters, tNIRS-1, which uses time-resolved spectroscopy, and conventional INVOS 5100C. Seventy-eight children-26 infants, 26 toddlers, and 26 schoolchildren-undergoing non-cardiac surgery were included. We investigated the differences in the rSO2 levels among the age groups and the correlation between the models and physiological factors influencing the rSO2 values. rSO2 measured by INVOS 5100C was significantly lower in infants than those in other patients. rSO2 measured by tNIRS-1 was higher in the toddler group than those in the other groups. The rSO2 values of tNIRS-1 and INVOS 5100C were moderately correlated (r = 0.41); however, those of INVOS 5100C were approximately 20% higher, and a ceiling effect was observed. The values in INVOS 5100C and tNIRS-1 were affected by blood pressure and the minimum alveolar concentration of sevoflurane, respectively. In pediatric patients undergoing non-cardiac surgery, rSO2 values differed across the three age groups, and the pattern of these differences varied between the two oximeters employing different algorithms. Further research must be conducted to clarify cerebral oxygenation in children.

Changes in Cerebral Hemodynamics During Systemic Pulmonary Shunt and Pulmonary Artery Banding in Infants with Congenital Heart Disease.

Palliative surgery is often performed in the treatment of congenital heart disease. Two representative palliative procedures are the systemic pulmonary shunt and pulmonary artery banding. Dramatic changes in cerebral hemodynamics may occur in these operations due to changes in the pulmonary-to-systemic blood flow ratio and systemic oxygenation. However, there seem to be almost no studies evaluating them. Accordingly, we evaluated cerebral perfusion by transcranial Doppler ultrasonography and cerebral oxygenation by near infrared spectroscopy during these procedures. In the post hoc analysis of a previous prospective observational study, cerebral blood flow velocities of the middle cerebral artery measured by transcranial Doppler were compared between the start and end of surgery as were the pulsatility index and resistance index. The cerebral oxygenation values were also compared between the start and end of surgery. Twenty-two infants with systemic pulmonary shunt and 20 infants with pulmonary artery banding were evaluated. There were no significant differences of the flow velocities between the start and end of surgery in either procedure. The pulsatility index significantly increased after pulmonary artery banding, which may compete with the increase in cerebral perfusion due to the increase in systemic blood flow. The cerebral oxygenation decreased in both procedures, possibly due to an increase in body temperature. Arterial oxygen saturation was almost the same before and after both procedures. Contrary to our expectation, the changes in cerebral hemodynamics in the palliative operations were small if the management of physiological indices such as arterial oxygen saturation was properly performed during the procedures.

Effects of ephedrine and phenylephrine on cerebral oxygenation: observational prospective study using near-infrared time-resolved spectroscopy.

It has been reported that cerebral oxygenation (ScO2) measured by near infrared spectroscopy is maintained or increased by treatment with ephedrine, whereas almost all previous reports demonstrated that phenylephrine reduced ScO2. As the mechanism of the latter, the interference of the extracranial blood flow, that is extracranial contamination, has been suspected. Accordingly, in this prospective observational study, we utilized time-resolved spectroscopy (TRS), in which the effect of extracranial contamination is thought to be minimal, and evaluated whether the same result was obtained. We measured the changes in ScO2 as well as the total cerebral hemoglobin concentration (tHb) after treatment with ephedrine or phenylephrine during laparoscopic surgery by using a tNIRS-1 (Hamamatsu Photonics, Hamamatsu, Japan), which is a commercial instrument utilizing TRS. Based on a mixed-effects model with random intercepts for ScO2 or tHb including mean blood pressure, the mean difference and 95% confidence interval were evaluated as well as the predicted mean difference and its confidence interval using the interquartile range of mean blood pressure. Fifty treatments with ephedrine or phenylephrine were done. The mean differences of ScO2 were less than 0.1% and the predicted mean differences were less than 1.1% for the two drugs. The mean differences of tHb were less than 0.02 µM and the predicted mean differences were less than 0.2 µM for the drugs. The changes in ScO2 and tHb after treatments with ephedrine and phenylephrine were very small and clinically insignificant when measured by TRS. Previous reports about phenylephrine may have been affected by extracranial contamination.

Chronological changes in plasma levobupivacaine concentrations after bilateral modified thoracoabdominal nerve block through perichondrial approach.

The local anesthetic (LA) systemic toxicity of trunk blocks is a major concern. Recently, modified thoracoabdominal nerve block through perichondrial approach (M-TAPA) has attracted attention; however, plasma LA level is unknown. We tested whether the peak plasma LA concentration following M-TAPA, using 25 mL of 0.25% levobupivacaine mixed with epinephrine on each side, would be below the toxic level (2.6 µg/mL). We recruited 10 patients undergoing abdominal surgery with planned M-TAPA between November 2021 and February 2022. In all patients, 25 mL of 0.25% levobupivacaine mixed with 1:200,000 epinephrine was administered on each side. Blood samples were obtained at 10, 20, 30, 45, 60, and 120 min after the block. The highest individual peak and the mean peak plasma LA concentrations were 1.03 and 0.73 µg/mL, respectively. We could not capture the peak in five patients; however, the highest concentrations in all patients were significantly lower than the toxic level. A negative correlation between the peak level and body weight was observed. Our results indicated that the plasma LA concentration following M-TAPA using total of 50 mL of 0.25% levobupivacaine with epinephrine remains below the toxic level. Further research is required due to the small sample size of this study.Trial registry number: UMIN000045406.

Change in cerebral circulation during the induction of anesthesia with remimazolam.

PURPOSE: Remimazolam is a new ultra-short-acting benzodiazepine with unknown effects on cerebral circulation. We measured total cerebral hemoglobin concentrations, which reflect cerebral blood volume (CBV), and cerebral oxygen saturation, using time-domain near-infrared spectroscopy, which can measure the absolute values of cerebral hemoglobin concentrations. We also measured cerebral blood flow velocity (CBFV) in the middle cerebral artery using transcranial Doppler as an indicator of cerebral blood flow (CBF). We did so to examine the effect of remimazolam on cerebral circulation in humans, as assessed CBV, CBF, and cerebral oxygen saturation. METHODS: This was a prospective, observational study. Fifteen patients without serious complications scheduled for general anesthesia were recruited. We measured total cerebral hemoglobin concentrations, CBFV, and cerebral oxygen saturation throughout the anesthetic induction course with remimazolam. RESULTS: Total cerebral hemoglobin concentrations did not change during the process (p = 0.51). In contrast, the mean CBFV was reduced by 11% (significant, p = 0.04). The drop in mean blood pressure following the induction of anesthesia was 17%; however, it was within the range of cerebrovascular autoregulation. Moreover, cerebral oxygen saturation increased by 4% (statistically significant, p < 0.01). CONCLUSIONS: We found that anesthetic induction with remimazolam did not alter CBV and reduced CBF in uncomplicated patients.

Differences of cerebral oxygen saturation in dialysis patients: a comparison of three principals of near infrared spectroscopy.

PURPOSE: It has been reported that cerebral oxygen saturation (rSO2) measured by near infrared spectroscopy is low in dialysis patients. We compared the rSO2 values of dialysis patients before living donor kidney transplantation and their donors as controls by using three spectroscopes that utilize different principals, the INVOS 5100C (spatially resolved spectroscopy), FORE-SIGHT ELITE (modified Beer-Lambert law) and tNIRS-1 (time-resolved spectroscopy). METHODS: Before induction of anesthesia, the sensors of one of the three spectroscopes were placed on the forehead and rSO2 values were recorded followed by the same measurement using the other two spectroscopes. The primary objective was to compare the rSO2 values of the dialysis patients and controls using the three spectroscopes by the unpaired t test. Then we compared the rSO2 values among the spectroscopes in both dialysis patients and controls by one-way ANOVA. Finally, we examined the relations between the rSO2 values and the physiological values by using the Pearson correlation coefficient. RESULTS: Fifteen pairs of dialysis patients and controls were studied. With the INVOS 5100 C, the values of the dialysis patients (59.7 ± 9.7% (mean ± standard deviation) were 13% lower than those of the controls (73.3 ± 6.9%) (P < 0.01). With the tNIRS-1, the values were 57.8 ± 4.8% in the dialysis patients and 63.3 ± 3.5% in the controls (P < 0.01). Almost no differences were observed with the FORE-SIGHT ELITE (71.6 ± 4.9% [dialysis patients] vs. 70.8 ± 4.3% [Controls]) (P = 0.62). Among the spectroscopes, the values were significantly different in both dialysis patients and controls. For the INVOS 5100C and tNIRS-1, correlation coefficients between rSO2 values and blood Hb and serum Alb were more than 0.5. CONCLUSIONS: The rSO2 values for comparisons between the dialysis patients and the controls were different according to differences of the principles of the near infrared spectroscopes. In the INVOS 5100C and tNIRS-1, rSO2 values may be related to blood Hb and serum Alb.

Effect of cerebrospinal fluid drainage pressure in descending and thoracoabdominal aortic repair: a prospective multicenter observational study.

PURPOSE: Cerebrospinal fluid drainage (CSFD) is recommended during open or endovascular thoracic aortic repair. However, the incidence of CSFD complications is still high. Recently, CSF pressure has been kept high to avoid complications, but the efficacy of CSFD at higher pressures has not been confirmed. We hypothesize that CSFD at higher pressures is effective for preventing motor deficits. METHODS: This prospective observational study included 14 hospitals that are members of the Japanese Society of Cardiovascular Anesthesiologists. Patients who underwent thoracic and thoracoabdominal aortic repair were divided into four groups: Group 1, CSF pressure around 10 mmHg; Group 2, CSF pressure around 15 mmHg; Group 3, CSFD initiated when motor evoked potential amplitudes decreased; and Group 4, no CSFD. We assessed the association between the CSFD group and motor deficits using mixed-effects logistic regression with a random intercept for the institution. RESULTS: Of 1072 patients in the study, 84 patients (open surgery, 51; thoracic endovascular aortic repair, 33) had motor deficits at discharge. Groups 1 and 2 were not associated with motor deficits (Group 1, odds ratio (OR): 1.53, 95% confidence interval (95% CI): 0.71-3.29, p = 0.276; Group 2, OR: 1.73, 95% CI: 0.62-4.82) when compared with Group 4. Group 3 was significantly more prone to motor deficits than Group 4 (OR: 2.56, 95% CI: 1.27-5.17, p = 0.009). CONCLUSION: CSFD is not associated with motor deficits in thoracic and thoracoabdominal aortic repair with CSF pressure around 10 or 15 mmHg.

Age Difference of the Relationship Between Cerebral Oxygen Saturation and Physiological Parameters in Pediatric Cardiac Surgery with Cardiopulmonary Bypass: Analysis Using the Random-Effects Model.

Recently, monitoring of cerebral oxygen saturation (ScO2) has become widespread in pediatric cardiac surgery. Our previous study reported that mean blood pressure (mBP) was the major contributor to ScO2 throughout cardiac surgery with cardiopulmonary bypass (CPB) in children weighing under 10 kg. We speculated that this result might be attributable to incomplete cerebral autoregulation in such young children. Accordingly, our hypothesis is that the relationship between ScO2 and the physiological parameters may change according to the growth of the children. ScO2 was measured with an INVOS 5100C (Somanetics, Troy, MI). Random-effects analysis was employed with ScO2 as a dependent variable, and seven physiological parameters (mBP, central venous pressure, nasopharyngeal temperature, SaO2, hematocrit, PaCO2, and pH) were entered as independent covariates. The analysis was performed during the pre-CPB, CPB, and post-CPB periods by dividing the patients into two groups: infants (Infant Group) and children who were more than 1 year old (Child Group). The Infant and Child Groups consisted of 28 and 21 patients. In the random-effects analysis, mBP was the major contributor to ScO2 during CPB in both groups. During the pre-CPB period, the effect of mBP was strongest in the Infant group. However, its effect was second to that of SaO2 in the Child Group. During the post-CPB period, SaO2 and mBP still affected ScO2 in the Infant group. However, the dominant contributors were unclear in the Child Group. Cerebral autoregulation may be immature in infants. In addition, it may be impaired during CPB even after 1 year of age.

Altered microvascular reactivity assessed by near-infrared spectroscopy after hepato-pancreato-biliary surgery.

Little is known about microcirculatory dysfunction following abdominal surgeries. This study aimed to evaluate changes in microvascular reactivity (MVR) before and after major abdominal surgery, assessed by near-infrared spectroscopy in conjunction with a vascular occlusion test. This prospective observational study included 50 adult patients who underwent hepato-pancreato-biliary surgery lasting ≥ 8 h. MVR was assessed by tissue oxygen saturation (StO2) changes in the plantar region of the foot during 3 min of vascular occlusion and subsequent release under general anesthesia before and after surgery. The primary outcome was alteration in the recovery slope of StO2 (RecStO2) and recovery time (tM) between the preoperative and postoperative values. Postoperative short-term outcome was represented by the Post-operative Morbidity Survey (POMS) score on the morning of postoperative day 2. After surgery, RecStO2 was reduced (0.74% [0.58-1.06]/s vs. 0.89% [0.62-1.41]/s, P = 0.001), and tM was longer (57.0 [42.9-71.0] s vs. 41.3 [35.5-56.5] s, P < 0.001), compared to the preoperative values. Macrohemodynamic variables such as cardiac index, arterial pressure, and stroke volume during postoperative measurement did not differ with or without relative MVR decline. In addition, the POMS score was not associated with postoperative alterations in microcirculatory responsiveness. MVR in the plantar region of the foot was reduced after major hepato-pancreato-biliary surgery regardless of macrocirculatory adequacy. Impaired MVR was not associated with short-term outcomes as long as macrocirculatory indices were well maintained. The impact of relative microcirculatory changes, especially combined with inadequate macrocirculation, on postoperative complications remains to be elucidated.Clinical Trial Registrations UMIN-CTR trial ID: 000033461.

Clinical features and significance of leukopenia occurring immediately after endovascular surgery.

PURPOSE: Inflammation after stent graft surgery is known as postimplantation syndrome (PIS) and it causes leukocytosis. However, we have experienced leukopenia in the very early postoperative phase of endovascular surgery at our institution. We investigated leukopenia, an under-recognized phenomenon that occurred after transcatheter aortic valve implantation (TAVI), endovascular aortic repair (EVAR), and thoracic endovascular aortic repair (TEVAR). METHODS: Records of patients who underwent TAVI, EVAR, and TEVAR between March 2018 and February 2019 were retrospectively reviewed. Primary outcomes were the decline rate of white blood cell count (DR-WBC) in the immediate postoperative period and its differences among surgical procedures. The secondary endpoint was the relationship between DR-WBC and infectious complications. Furthermore, the incidence of PIS and its differences among the procedures and associations with DR-WBC were evaluated. RESULTS: A total of 108 patients (TAVI 41, EVAR 37, TEVAR 30) were included. DR-WBC immediately after surgery was higher in the TAVI group when compared with other groups (TAVI, 43.1 ± 22.6%; EVAR, 27.6 ± 17.3%; TEVAR, 25.4 ± 27.4%; P < 0.01). DR-WBC was not significantly different regardless of postoperative infection (P = 0.45) or PIS (P = 0.62). The incidence rate of PIS was higher in the EVAR group compared with the TAVI group, and was not associated with DR-WBC. CONCLUSIONS: Leukopenia was a common phenomenon immediately after endovascular surgery, especially TAVI. It resolved a day after surgery and was not associated with PIS or infectious complications. Therefore, it seems to be a transient abnormal hematological finding and a self-limiting condition.

The relationship between years of anesthesia experience and first-time intubation success rate with direct laryngoscope and video laryngoscope in infants: a retrospective observational study.

PURPOSE: Studies in adults have reported that video laryngoscope is more useful than direct laryngoscope when training less experienced anesthesiologists. However, whether this is true for infants remains unclear. Therefore, this study aimed to evaluate whether the use of video laryngoscope would result in smaller differences in success rate according to anesthesiologists' expertise than those in direct laryngoscope. METHODS: Medical records and video recordings from the operating room of patients aged < 1 year who underwent non-cardiac surgery between March 2019 and September 2021 were reviewed. Tracheal intubations between April 8, 2020, and June 20, 2021, were excluded due to the shortage of video laryngoscope blades during the COVID-19 pandemic. Rates of first-time tracheal intubation success were compared by years of anesthesia experience and initial intubation device. RESULTS: In total, 125 of 175 tracheal intubations were analyzed (direct laryngoscope group, n = 72; video laryngoscope group, n = 53). The first-time tracheal intubation success rate increased with years of experience as an anesthesiologist in the direct laryngoscope group (odds ratio OR 1.70, 95% confidence interval CI 1.15, 2.49; P = 0.0070), but not the video laryngoscope group (OR 0.99, 95% CI 0.74, 1.35; P = 0.99). CONCLUSION: The differences in success rate according to the anesthesiologists' years of experience were non-significant when using video laryngoscope in infants, compared to those in direct laryngoscope.

Microdevice with an Integrated Clark-Type Oxygen Electrode for the Measurement of the Respiratory Activity of Cells.

A microdevice for the measurement of the respiratory activity of cells was fabricated using a microfabricated Clark-type oxygen electrode. The oxygen electrode was completed in a dry state and was activated by introducing water necessary for the reduction of oxygen in the form of water vapor through an oxygen-permeable membrane, which significantly facilitated handling of the device even by nonspecialists. The use of a thin paper layer stabilized the current response and enabled stable continuous operation of the oxygen electrode without current disturbance caused by the evaporation of water. The microdevice was tested in some model experiments including the measurement of the respiratory activity of Escherichia coli (E. coli), evaluation of the efficacy of antibiotics, and measurement of the antibacterial activity of neutrophils, all of which demonstrated that the consumption of dissolved oxygen by cells can be monitored clearly by following an easy procedure for the preparation of the measurements.

Lipopolysaccharide preconditioning reduces liver metastasis of Colon26 cells by enhancing antitumor activity of natural killer cells and natural killer T cells in murine liver.

BACKGROUND AND AIM: Lipopolysaccharide (LPS) preconditioning drastically augments bactericidal activity but reduces the host inflammatory response. Therefore, it may be beneficial to prevent postoperative infectious complications and mitigate host damage by surgical stress. Considering its clinical application, how LPS preconditioning influences the antitumor effect in the liver is an important issue. We then investigated the effect of LPS preconditioning on antitumor activity against Colon26 tumor cells in mice. METHODS: Lipopolysaccharide preconditioning was induced in mice by the intraperitoneal injection of 5 µg/kg LPS for three consecutive days. Intraportal inoculation of Colon26 cells, which express luminescent protein called Nano-lantern, was performed to evaluate the effect of LPS preconditioning on tumor liver metastasis. The antitumor activities of cytotoxic liver lymphocytes, especially natural killer (NK) cells and natural killer T (NKT) cells, against Colon26 cells were also examined in LPS preconditioned mice. RESULTS: Lipopolysaccharide preconditioning remarkably prevented liver metastasis of Colon26 cells, as observed by IVIS imaging system, and prolonged survival after tumor inoculation. LPS preconditioning increased the proportions and number of liver NK cells and NKT cells and augmented their intracellular perforin and granzyme B expression, while reducing their intracellular expression of IFN-γ. An in vitro antitumor cytotoxicity assay revealed that LPS preconditioning significantly augmented antitumor cytotoxicities of the liver NK cells and NKT cells, especially NKT cells, against Colon26 cells. CONCLUSIONS: Lipopolysaccharide preconditioning potently augmented antitumor cytotoxicity of liver NK cells and NKT cells, thereby improving mouse survival after intraportal inoculation of Colon26 tumor cells. It may be useful for perioperative care in oncological patients.

Changes of cerebral oxygenation indices measured by near infrared time-resolved spectroscopy during spinal anesthesia for cesarean section: Simultaneous measurement with cerebral blood flow.

AIM: To measure the changes in cerebral oxygenation indices by near infrared time-resolved spectroscopy and the cerebral blood flow simultaneously after spinal anesthesia for cesarean section. METHODS: This prospective observational study was conducted for 25 pregnant women scheduled for elective cesarean section under spinal anesthesia. During a period of 15 min after spinal anesthesia, cerebral oxygenation (ScO2 ), and the total cerebral hemoglobin concentration (tHb) were measured using near infrared time-resolved spectroscopy and mean cerebral blood flow velocity (Vm) was measured using transcranial Doppler ultrasonography. Next, in the women who had nausea during the observed period, we compared these values when nausea was detected with those when it was not. RESULTS: Mean arterial pressure (MAP) decreased to around 60 mmHg (by 25% compared to the control) 6 min after spinal anesthesia. Compared to the control, ScO2 decreased by about 3% after 6 min and then gradually increased. The tHb, which reflects cerebral blood volume started to decrease just after spinal anesthesia and this continued until 12 min (the decrease was about 12%). Vm decreased by about 7%. In the 14 women who had nausea, MAP, Vm, and ScO2 values when nausea was detected were significantly lower than when it was not. CONCLUSION: The changes in cerebral hemodynamics may be small after spinal anesthesia in ordinary cesarean section compared to the reduction of systemic arterial blood pressure. There might be greater decreases in cerebral blood flow and oxygenation when nausea occurred in the pregnant women who experienced it after spinal anesthesia.

The Relationships of Cerebral and Somatic Oxygen Saturation with Physiological Parameters in Pediatric Cardiac Surgery with Cardiopulmonary Bypass: Analysis Using the Random-Effects Model.

Recently, tissue oxygenation in pediatric heart surgery is measured by using near-infrared spectroscopy. Monitoring of cerebral oxygen saturation (ScO2) is most common but that of somatic tissue oxygen saturation (SrO2) is also gradually becoming widespread. However, the value of their monitoring is not well established. One of the reasons for this may be that the physiological factors affecting ScO2 and SrO2 have not been sufficiently clarified. Accordingly, we prospectively observed the changes in ScO2 and SrO2 simultaneously throughout cardiac surgery with cardiopulmonary bypass (CPB) in children weighing under 10 kg and evaluated their relationships with physiological parameters by using the random-effects model. ScO2 and SrO2 were measured with an INVOS 5100C (Somanetics, Troy, MI, USA). The random-effects analysis was applied for ScO2 and SrO2, as dependent variables, and seven physiological parameters (mean blood pressure, central venous pressure, rectal temperature, SaO2, hematocrit PaCO2, and pH) were entered as independent covariates. The analysis was performed during the pre-CPB, CPB, and post-CPB periods. Next, the same analysis was performed by dividing the patients into univentricular and biventricular physiological types. Forty-one children were evaluated. Through the whole surgical period, ScO2 correlated strongly with mean blood pressure regardless of the physiological type. On the other hand, the contribution of mean blood pressure to SrO2 was weak and various other parameters were related to SrO2 changes. Thus, the physiological parameters affecting ScO2 and SrO2 were rather different. Accordingly, the significance of monitoring of cerebral and somatic tissue oxygen saturation in pediatric cardiac surgery should be further evaluated.

Diagnostic timing dependent characteristics of acute kidney injury following hepatectomy: a retrospective historical cohort analysis.

BACKGROUND: The timing of diagnosis of post-hepatectomy acute kidney injury (AKI) has rarely been investigated. The aim of this retrospective study was to reveal the differences between AKI subtypes following hepatectomy, as classified by timing of diagnosis. METHOD: Post-hepatectomy AKI was classified as very transient AKI (vtAKI; criteria satisfied by the serum creatinine value immediately after surgery) or non-transient AKI (ntAKI; all other AKI types except for vtAKI). Multivariate logistic regression analyses for both AKI types were performed separately to identify differences in known perioperative AKI risk factors. The impacts of each AKI subtype on postoperative complications, hospital stay and renal outcome at discharge were also evaluated. RESULTS: AKI was diagnosed in 135 of 750 patients (18.0%); 82 and 53 patients were classified as vtAKI and ntAKI, respectively. In multivariate analysis, even among the perioperative factors associated with whole AKI, there were distinct relationships depending on vtAKI or ntAKI. Furthermore, only ntAKI was associated with postoperative complications, longer hospital stays and impaired renal function at discharge. CONCLUSIONS: Based on the results of this study, future post-hepatectomy AKI studies should only include ntAKI and exclude vtAKI, as vtAKI has minimal clinical impact despite accounting for a significant proportion of AKI patients. CLINICAL TRIAL REGISTRATIONS: None.

Intraosseous transfusion of hemoglobin vesicles in the treatment of hemorrhagic shock with collapsed vessels in a rabbit model.

BACKGROUNDS: Intravenous transfusion sometimes encounters difficulty under prehospital conditions when peripheral vessels are collapsed and inaccessible. We investigated whether the cellular type hemoglobin-based oxygen carriers (Hemoglobin Vesicles: HbVs) allow intraosseous administration into blood circulation for the resuscitation of rabbits with severe hemorrhagic shock. STUDY DESIGN AND METHODS: New Zealand white rabbits (2.5 kg average) were set in severe hemorrhagic shock [mean arterial pressure (MAP): 21 ± 2 mm Hg, Hb 5.1 ± 0.8 g/dL]. Immediately thereafter, 12 mL/kg of HbVs, 5% human serum albumin (HSA), autologous whole blood (WB), stored red blood cells (RBCs) or 36 mL/kg of Lactated Ringer's (LR) were intraosseously transfused, followed by an additional intraosseous transfusion with 8 mL/kg of HSA (following HbV, HSA or stored RBC transfusion), or WB or 24 mL/kg of LR (following LR transfusion), respectively. RESULTS: Intraosseous transfusion of HbVs increased MAP (48 ± 9 mm Hg) and improved hypohemoglobinemia (7.1 ± 0.6 g/dL) as well as WB or RBC transfusion. In contrast, neither HSA nor LR improved hemodynamics or Hb levels. Seven out of 10 rabbits receiving HbVs survived for 24 hours, while only one out of 10 rabbits receiving LR survived (WB and RBC; 100% survivals, HSA; 30% survival). CONCLUSIONS: Intraosseous infusion of HbVs might be an effective initial treatment to maintain hemodynamics during acute hemorrhagic shock. This approach could be used in emergency situations in which access to peripheral vessels is difficult.

Two-stage goal-directed therapy protocol for non-donor open hepatectomy: an interventional before-after study.

PURPOSE: Hemodynamic management during low central venous pressure (L-CVP)-assisted hepatectomy involves fluid restriction during resection and fluid resuscitation after resection. Recently, high stroke volume variation (SVV) has been reported as an alternative to L-CVP for reducing blood loss during a hepatectomy. The current study evaluated the impact of a newly implemented SVV-based goal-directed therapy (GDT) protocol on blood loss during hepatectomy. METHODS: We conducted a before-after comparative study, which included L-CVP-assisted hepatectomy cases (control group) and GDT-assisted hepatectomy cases (intervention group). The GDT protocol included SVV, cardiac index, and mean arterial pressure as hemodynamic parameters. The target SVV ranges were ≥ 13% and ≤ 12% before and after the resection, respectively. The primary endpoint was the proportion of patients whose blood loss was < 400 mL (median of our hepatectomy cases) in the GDT group, and it was compared to a predefined threshold of 50%. We also investigated factors associated with blood loss using multiple regression analysis. RESULTS: We included 66 patients in the control group and 50 in the GDT group. In the GDT group, the median blood loss was 220 mL and 36 patients (72%) lost < 400 mL blood. This was significantly greater than 50% (P < 0.001). Post-resection GDT-guided fluid optimization reduced positive intraoperative fluid balance compared to that achieved by the conventional fluid therapy used in the control. Multiple regression analysis showed that GDT application, epidural anesthesia, operative time, and hydroxyethyl-starch infusion volume were associated with blood loss. CONCLUSION: Compared to conventional management, SVV-guided GDT may reduce blood loss during hepatectomies.

Isoflurane induces c-Fos expression in the area postrema of the rat.

INTRODUCTION: Volatile anesthetics are speculated to cause postoperative nausea and vomiting via stimulation of the chemoreceptor trigger zone (CTZ). However, the precise mechanism underlying the emetic action of these drugs is not well understood. In this study, we assessed whether isoflurane induced the expression of c-Fos, a neuronal activation marker, in the area postrema (AP), the locus of the CTZ, in rats, which do not have vomiting action. MATERIALS AND METHODS: Male rats were exposed to 1.3% isoflurane for 0-240 min, or to various concentrations of isoflurane (0, 1.3%, or 2.6%) for 120 min. Finally, the rats were exposed to 1.3% isoflurane for 120 min after ondansetron administration. After the treatments, immunohistochemistry of the rat AP was performed using c-Fos antibody staining. RESULTS: One-way analysis of variance showed that isoflurane exposure significantly increased c-Fos expression in the AP; however, the rats pretreated with 4 mg/kg ondansetron showed significantly decreased c-Fos expression. Moreover, we evaluated the effect of the anesthetic on inducing pica in the rats, and found that kaolin intake was not influenced by isoflurane exposure. CONCLUSION: Overall, these results suggest that isoflurane activates AP neurons and may be involved in the emetic mechanism of isoflurane. This study further suggests the feasibility of using rats as a model for studying emetic mechanisms of drugs, despite their lack of vomit action.