Yoshifumi Kotake

Improved accuracy of cardiac output estimation by the partial CO2 rebreathing method

ObjectiveThis study investigated the accuracy of the NICO monitor equipped with the newer software. Additionally, the effects of the increased dead space produced by the NICO monitor on ventilatory settings were investi- gated.MethodsForty-two patients undergoing elective aortic reconstruction participated in this prospective, obser- vational study at a university hospital. Cardiac output was continuously monitored using both the NICO monitor and continuous cardiac output (CCO) measured by a pulmonary artery catheter. A NICO monitor equipped with ver. 4.2 software was used for the first 21 patients while a NICO monitor equipped with ver. 5.0 software was used for the rest of␣the patients. Cardiac output measured by bolus thermo- dilution (BCO) at 30xa0min intervals was used as a reference.ResultsThe biasu200a±u200aprecision of the NICO monitor was 0.18u200a±u200a0.88xa0l/min with ver. 4.2 software (nxa0=xa0182) and 0.18u200a±u200a0.83xa0l/min with 5.0 software (nxa0=xa0194). The accuracy of the NICO monitor is comparable to CCO, whose biasu200a± &!hairsp;precision against BCO is 0.19u200a±u200a0.81xa0l/min (nxa0=xa0376). At the␣same level of CO2 production and minute ventilation, PaCO2 was lower in the patients monitored by NICO with ver. 5.0 software than patients with ver. 4.2 software.ConclusionsThis study demonstrated the improved perfor- mance of the NICO monitor with updated software. The performance of the NICO monitor with ver. 4.2 or later software is similar to CCO. However, the cardiac output measurement did not fulfill the criteria of interchangeability to the cardiac output measurement by bolus thermodilution. Updates to ver. 5.0 attenuated the effects of rebreathing introduced by the NICO monitor without compromising the accuracy of the cardiac output measurement.

The comparison between stroke volume variation and filling pressure as an estimate of right ventricular preload in patients undergoing renal transplantation

PurposeThe purpose of this prospective, observational study was to respiratory variation of stroke volume (stroke volume variation, SVV) against central venous pressure (CVP) and pulmonary artery diastolic pressure (PADP) as an estimate of right and left ventricular preload.MethodsWith IRB approval and informed consent, 31 patients undergoing living related renal transplantation were analyzed. Under general anesthesia with positive pressure ventilation, stroke volume index and SVV were continuously monitored with FloTrac/Vigileo monitor. Right ventricular end-diastolic volume index (RVEDVI) as well as CVP and PADP were continuously monitored with volumetric pulmonary artery catheter. Data of every 30xa0min interval were used for analysis. The relationship between RVEDVI and CVP, PADP, SVV was analyzed with non-linear regression and the goodness-of-fit was assessed with coefficient of determination (R2) of each regression curve. The ability of CVP, PADP and SVV to correctly differentiate RVEDVI <100, <120 or >138xa0ml/m2, which were used to guide fluid administration, was also assessed with ROC analysis.ResultsThree hundred forty-eight data sets were obtained and analyzed. The goodness of fit between RVEDVI and SVV (R2xa0=xa00.48) was better than that between RVEDVI and CVP or PADP (R2xa0=xa00.19 and 0.33, respectively). The area under the ROC curve of SVV was significantly high compared to CVP or PADP.ConclusionsThis study confirmed the theoretical framework of right ventricular preload and ventricular filling pressure and respiratory variation of stroke volume. The result also suggests that SVV can correctly predict preload status compared to pressure-based indices.

Low molecular weight pentastarch is more effective than crystalloid solution in goal-directed fluid management in patients undergoing major gastrointestinal surgery

BackgroundThis prospective observational study compared the volume effect between hydroxyethyl starch (HES) and crystalloid solution and its context dependency in intraoperative goal-directed fluid management.MethodsWith institutional review board (IRB) approval, 35 patients undergoing major gastrointestinal surgery were enrolled. Fluid challenge consisting of 250xa0ml of either bicarbonate Ringer solution (BRS) or low molecular weight pentastarch (HES 70/0.5) was given to maintain stroke volume index >35xa0ml/m2. The context of fluid challenge was classified as related to either epidural block (EB) or blood loss (BL) or as nonspecific. The primary end point was the interval between index fluid challenge and the next fluid challenge, and the secondary end point was the hemodynamic parameter at the end of fluid challenge. Differences in these parameters in each clinical context were compared between BRS and HES 70/0.5. A p value <0.05 was considered statistically significant.ResultsEighty-eight, 77, and 127 fluid challenges were classified as related to EB and BL and as nonspecific, respectively. In the nonspecific condition, the median (range) interval after fluid challenge with HES 70/0.5 and BRS was 45 (11–162)xa0min and 18 (8–44)xa0min, respectively, and the difference was statistically significant. Also, mean arterial pressure and stroke volume index significantly increased, whereas stroke volume variation significantly decreased after fluid challenge with HES 70/0.5 compared with BRS. Such differences were not observed in the other situations.ConclusionsHES 70/0.5 exerted larger volume effects than did crystalloid under nonspecific conditions. However, similar volume effects were observed during volume loss and extensive sympathetic blockade.

Atrial natriuretic peptide reduces hepatic ischemia–reperfusion injury in rabbits

PurposeAtrial natriuretic peptide (ANP) has been known to be protective against hepatic ischemia/reperfusion injury. The purpose of this study was to verify the hypothesis that ANP conserves microvascular circulation and reduces ischemia–reperfusion injury in the in vivo rabbit model.MethodsWith IRB approval, 30 male Japanese white rabbits under pentobarbital anesthesia were studied. These animals were randomly assigned to the following three groups (nxa0=xa010 each): control, ANP, and sham group. Animals in the ANP group received continuous infusion of ANP at 0.1xa0μg/kg/min throughout the study period. Animals in control and ANP groups underwent 90xa0min of partial hepatic ischemia by clamping the right hepatic artery and portal vein. Descending aortic blood flow (AoF) was monitored with a transit-time ultrasound flowmeter. Hepatic tissue microvascular blood flow (HTBF) at both right (ischemic) and left (nonischemic) lobe was intermittently evaluated with the hydrogen clearance method. After 180xa0min of reperfusion, hepatic injury was determined with serum AST and ALT. Galactose clearance of reperfused right lobe was also measured as an indicator of hepatic metabolic function. Histopathological change and the number of apoptotic hepatocytes were also evaluated.ResultsSystemic hemodynamic data including mean arterial pressure, heart rate, and AoF did not differ among the three groups during the study period. ANP attenuated ischemia-induced right HTBF decrease. ANP also suppressed histopathological degeneration, apoptosis, and decline in galactose clearance after reperfusion.ConclusionsANP attenuated hepatic microvascular dysfunction and hepatocyte injury after reperfusion without significant hemodynamic change.

Recurrent ST-segment elevation on ECG and ventricular tachycardia during neurosurgical anesthesia

This article reports an unusual case of repeated intraoperative myocardial ischemia and ventricular arrhythmia during neurosurgical anesthesia. The presentation was clinically diagnosed as coronary spasm after successful resuscitation. Intraoperative prostaglandin E1 and β-adrenergic blockade, as well as vagal stimulation due to surgical manipulation, may have contributed to the episode.

Pros and cons of tetrastarch solution for critically ill patients

Proper fluid management is crucial for the management of critically ill patients. However, there is a continuing debate about the choice of the fluid, i.e., crystalloid vs. colloid. Colloid solution is theoretically advantageous to the crystalloid because of larger volume effect and less interstitial fluid accumulation, and hydroxyethyl starch (HES) is most frequently used for perioperative setting. Nevertheless, application of HES solution is relatively limited due to its side effects including renal toxicity and coagulopathy. Since prolonged presence of large HES molecule is responsible for these side effects, rapidly degradable HES solution with low degree of substitution (tetrastarch) supposedly has less potential for negative effects. Thus, tetrastarch may be more frequently used in the ICU setting. However, several large-scale randomized trials reported that administration of tetrastarch solution to the patients with severe sepsis has negative effects on mortality and renal function. These results triggered further debate and regulatory responses around the world. This narrative review intended to describe the currently available evidence about the advantages and disadvantages of tetrastarch in the ICU setting.

Validation of inflationary non-invasive blood pressure monitoring in adult surgical patients

Oscillometric determination of blood pressure may be advantageous, as cuff inflation requires lower cuff pressure and shorter duration than deflation. In this observational study, we compared the blood pressure value, cuff pressure, and duration of cuff inflation between a prototype of inflationary non-invasive blood pressure (NIBP) and conventional deflationary NIBP in adult patients during anesthesia. Three hundred and twenty-three pairs of measurements were obtained from 64 subjects. The bias and precision of systolic pressure and diastolic pressure were 2.9xa0±xa08.3 and 5.6xa0±xa06.1xa0mmHg, respectively. Inflationary NIBP could better determine NIBP with lower cuff pressure than deflationary NIBP (124xa0±xa022 vs. 160xa0±xa033xa0mmHg, pxa0<xa00.05). Inflationary NIBP could also determine NIBP more quickly (13.0xa0±xa02.3 vs. 32.7xa0±xa013.6xa0s, pxa0<xa00.05). These data suggest that inflationary NIBP may reduce cuff-related discomfort and complications, and has reasonable accuracy compared to deflationary NIBP in adult surgical patients.

Response Time of Different Methods of Cardiac Output Monitoring During Cardiopulmonary Resuscitation and Recovery

partial pressure (PETCO2) and mixed venous hemoglobin oxygen saturation (SvO2) also were continuously monitored and recorded. During the laparotomy, hypotension and tachycardia were noted and were accompanied by facial flushing. This was diagnosed as mesenteric traction syndrome and was treated with fluid administration and intermittent intravenous ephedrine. During this period, high cardiac output was recorded with all devices. The maximal values recorded were 6.9 L/min, 9.2 L/min, 17.4 L/min, and 17.9 L/min via the EDM, NICO, STAT CCO, and trend CCO monitors, respectively. At this point, the SvO2 was 89% and VCO2 was 137 mL/min. These symptoms eventually disappeared, and the patient’s CO subsequently stabilized (measured as 5.5 L/min, 5.1 L/min, 10.1 L/min, and 11.3 L/min via the EDM, NICO, STAT CCO, and CCO monitors, respectively; SvO2 85%, VCO2 126 mL/min. The CO at this point as measured with a bolus thermodilution was 7.0 L/min. During surgical exposure of the aortic aneurysm, a sudden onset of ventricular premature contraction was followed by sustained ventricular tachycardia (VT). Because initial DC cardioversion failed to stop the VT, phenylephrine, lidocaine, nitroglycerin, and epinephrine were administered while closed-chest compression was provided. During CPR, the patient was manually ventilated to ensure adequate ventilation. The minute volume provided during CPR was between 11 L/min and 12 L/min. The third DC cardioversion finally restored the patient to sinus rhythm. The duration of VT was 9 minutes, and chest compression provided a systolic pressure of more than 60 mmHg and diastolic pressure of more than 20 mmHg during CPR. The trend for the EDM, NICO, STAT CCO, and trend CCO monitors are summarized in Figure 1, along with PETCO2 and SvO2 during the CPR period. The CO measured with EDM varied from 0 to 2.5 L/min, and the signal of descending aortic blood flow caused by chest compression was clearly visible during this event using EDM. Three rebreathing cycles were used with a NICO monitor during CPR. The first rebreathing cycles were applied at 2 minutes after the onset of VT and the CO and VCO2 were reported as 2.9 L/min and 104 mL/min, respectively. The second cycle was applied 5 minutes after the onset of VT and failed to estimate the CO. The third rebreathing cycle was applied at 8 minutes after the onset of VT, and the CO and VCO2 were

Evaluation of multiwave pulse total-hemoglobinometer during general anesthesia

The purpose of this prospective study was to evaluate the accuracy and trending ability of a four-wavelength pulse-total hemoglobinometer that continuously and noninvasively measures hemoglobin in surgical patients. With IRB approval and informed consent, spectrophotometric hemoglobin (SpHb) was measured with a pulse-total hemoglobinometer manufactured by Nihon Kohden Corp (Tokyo, Japan) and compared to the CO-oximeter equipped with blood gas analyzer. Two hundred twenty-five samples from 56 subjects underwent analysis. Bland–Altman analysis revealed that the biasxa0±xa0precision of the current technology was 0.0xa0±xa01.4xa0g/dl and −0.2xa0±xa01.3xa0g/dl for total samples and samples with 8xa0<xa0Hbxa0<xa011xa0g/dl, respectively. The percentages of samples with intermediate risk of therapeutic error in error grid analysis and the concordance rate of 4-quadrant trending assay was 17xa0% and 77xa0%, respectively. The Cohen kappa statistic for Hbxa0<xa010xa0g/dl was 0.38, suggesting that the agreement between SpHb and CO-oximeter-derived Hb was fair. Collectively, wide limits of agreement, especially at the critical level of hemoglobin, and less than moderate agreement against CO-oximeter-derived hemoglobin preclude the use of the pulse-total hemoglobinometer as a decision-making tool for transfusion.

Descending aortic blood flow during aortic cross-clamp indicates postoperative splanchnic perfusion and gastrointestinal function in patients undergoing aortic reconstruction

BACKGROUNDnThe purpose of this observational study was to investigate the relationship between splanchnic and renal blood flow during infrarenal aortic cross-clamp (XC) and postoperative gastrointestinal perfusion and function.nnnMETHODSnDescending aortic blood flow (DABF) was continuously monitored with an oesophageal Doppler monitor (Cardio-Q, Deltex Ltd, Chichester, UK) in 31 patients undergoing elective abdominal aortic aneurysm repair. Cardiac output (CO) was determined by indocyanine green dilution before, during, and after XC. Perioperative gastrointestinal perfusion was assessed by gastric intramucosal pH (pHi, Tonocap, GE Healthcare, Helsinki, Finland). Postoperative gastrointestinal recovery was assessed by the number of postoperative days until the patient successfully resumed solid food intake. The relationship between the mean DABF during XC and gastric pHi after XC release and postoperative gastrointestinal recovery was analysed with Spearmans correlation coefficient.nnnRESULTSnaccounted for ∼ 55% of CO during XC and significantly decreased during XC, despite arterial pressure remaining within an optimal range. There were two distinct relationships between DABF during XC and gastric pHi after XC release. Gastric pHi steeply and linearly declined when indexed DABF was below 0.82 litre min(-1) m(-2). Above this critical value, there was no linear relationship between them. The duration of postoperative gastrointestinal dysfunction was inversely correlated with the mean DABF during XC. The best cut-off value of the mean indexed DABF during XC to prevent prolonged gastrointestinal dysfunction was 1.2 litre min(-1) m(-2).nnnCONCLUSIONSnDecreased DABF during XC associates splanchnic hypoperfusion after XC release and delayed recovery of gastrointestinal function.