Kan Takahashi

Association of the Plasma Platelet-Derived Microparticles to Platelet Count Ratio with Hospital Mortality and Disseminated Intravascular Coagulopathy in Critically Ill Patients

AIM The role of platelet-derived microparticles (PDMPs) in the crosstalk between coagulopathy and inflammation in critically ill patients remains unclear. The aim of this cohort observational study was to investigate the associations between the PDMP levels and hospital mortality or disseminated intravascular coagulopathy (DIC). METHODS This study included 119 patients who were admitted to the ICU. The PDMP levels were measured using an enzyme-linked immunosorbent assay three times a week, for a total of 372 samples. We calculated the maximum (max) PDMP value, max PDMP/platelet (PDMP/Plts) ratio (converted to the PDMP levels per 10(4) platelets) and nadir platelet count during the ICU stay. Baseline patient data and scores, including the Japanese Association for Acute Medicine (JAAM) DIC score, were collected, and potential predictors were analyzed for possible associations with hospital mortality. RESULTS The max PDMP/Plts ratio was significantly different comparing the survivors (n=98: median, 2.54) and non-survivors (n=21: median 17.59; p＜0.001). There was a weak but statistically significant negative correlation between the max PDMP level and nadir platelet count (r=-0.332, p＜0.001). The max PDMP level and max PDMP/Plts ratio were higher in the DIC group (81.48 and 9.27, respectively) than in the non-DIC group (34.88 and 2.35, p=0.001 and p＜0.001, respectively). The max PDMP/Plts ratio was the only variable found to be independently associated with hospital mortality according to a multivariate logistic regression analysis. CONCLUSIONS PDMPs are involved in the development of DIC but are not related to hospital mortality. There is a good association between the PDMP/Plts ratio and hospital mortality and/or DIC in critically ill patients.

Dissociation between lactate accumulation and acidosis in middle cerebral artery-occluded rats assessed by 31P and 1H NMR metabolic images under A 2-T magnetic field

The relationships among tissue edema, lactate accumulation, and intracellular pH in middle cerebral artery (MCA)-occluded rats were investigated with multiecho 1H magnetic resonance imaging and spatially resolved metabolic images constructed by 1H and 31P nuclear magnetic resonance (NMR) chemical shift imaging (CSI). For the effective and sensitive detection of NMR signals from the brain, outer volume suppression (OVS), reduced k-space sampling and proton irradiation were incorporated into the CSI sequences. The consecutive three measurements of calculated T2 image, lactate image, and pH image which were required for 3.75 h were repeated for four cycles of 1-16 h after MCA occlusion. Tissue edema and lactate accumulation in the infarcted region were gradually and consistently increased during the 15-h observation period. In contrast, severe acidosis was already detected on the first pH image (2-4.7 h after MCA occlusion); thereafter, the degree of acidosis became milder and showed no further progression. The dissociation between the time courses of the lactate accumulation and pH decrease was clearly demonstrated by the NMR metabolic images. Acid-base balance in cerebral infarction might be affected not only by lactate production but also by complicated interactions with tissue edema and some other factors.

The effects of halothane and isoflurane on the phosphoenergetic state of the liver during hemorrhagic shock in rats : An in vivo 31P nuclear magnetic resonance spectroscopic study

We studied the effects of halothane versus isoflurane on the phosphoenergetic state and intracellular pH (pHi) of the rat liver using in vivo31 P nuclear magnetic resonance (NMR) spectroscopy during and after hemorrhagic shock.Seventeen rats were anesthetized with 1 minimum alveolar anesthetic concentration of halothane or isoflurane. The mean arterial blood pressure was reduced to 40 mm Hg and maintained at this level for 45 min by withdrawing blood from the common carotid artery. The shed blood was then returned slowly. In vivo31 P NMR spectra were consecutively collected throughout the study. The phosphoenergetic state of the liver was evaluated from the changes in adenosine triphosphate (ATP) and inorganic phosphate (Pi) levels. pHi was calculated from the chemical shifts of Pi and alpha-ATP peaks. During hemorrhagic shock, beta-ATP decreased to 35% and 45%, and Pi increased to 300% and 230% of their initial values in the halothane and isoflurane groups, respectively. Intracellular acidosis was more severe in the halothane group. The recoveries of beta-ATP and Pi were better in the isoflurane group. Halothane showed a more detrimental effect than isoflurane on the hepatic phosphoenergetic level during and after hemorrhagic shock. (Anesth Analg 1997;85:347-52)

Relationship between gluconeogenesis and phosphoenergetics in rat liver assessed by in vivo 13C and 31P NMR spectroscopy.

The relationship between the phosphoenergetic state and gluconeogenesis in the liver after ischemic damage was investigated using living rats. The ATP level was determined with in vivo 31P nuclear magnetic resonance spectroscopy, and gluconeogenesis was evaluated with in vivo 31C NMR spectroscopy using L‐[3‐13C]alanine as a tracer. These two measurements were alternated repeatedly. The rats were divided into three groups: without ischemia (group A); with 10 min ischemia (group B); and with 30 min ischemia (group C). ATP was depleted to 20% of the preischemic state after 10 min ischemia and this level was maintained during 30 min ischemia. After reperfusion, the ATP level was partially restored, but the recovery was smaller in group C. Infusion of [3‐13C]alanine was started immediately after the reperfusion. In vivo 13C NMR disclosed changes in the alanine C3, glutamine/glutamate C2 and C3, glucose C1–6, and glycogen C1 signals in the liver. After 60 min infusion of [3‐13C]alanine, the ATP level correlated negatively with the signal intensity of alanine (r=0.664, p=0.008) and positively with those of glucose and glyogen (r=0.586, p=0.023, and r=0.643, p=0.011, respectively). These results suggest that the ATP level participates in gluconeogenesis and glycogenesis in the liver. Such multinuclear in vivo NMR observations might uncover new aspects of the metabolic function of the liver in the in vivo state.

Problematic use of a Pentax AWS-S200 in emergency and disaster medicine

ficulties in seeing the colour change of the soda lime in the re-usable canister when it has fully expired. We are currently looking at changing the colour and the material used in the re-usable canister. The CO2 re-usable canister handle acts as an integrated condenser, collecting water within the canister. The canister was designed to accept the maximum amount of water that could be generated within the life of the soda lime. Therefore, each time the user empties/replaces the CO2 absorbent, the excess water is also removed from the system. Whilst observing the colour change of soda lime is an accepted method of visually checking that the soda lime has expired, it is more likely that users would use the FICO2 reading from their gas module or patient monitor to check that the soda lime is fully exhausted. It is the anaesthetist’s decision to replace exhausted soda lime as they see appropriate, but in today’s cost-conscious and environmentally-friendly hospitals, it may be more accurate to use the FICO2 value as a trigger for changing soda lime rather than a visual inspection of the re-usable soda lime canister to see if it needs changing.

The importance of usage guidance from anesthesiologists when disseminating video laryngoscopes throughout emergency departments and intensive care units

Many anesthesiologists use the video laryngoscopes (Airway scope (Pentax Co., Tokyo, Japan) or McGRATH MAC (Aircraft Medical Lt., Edinburgh, UK)) as their first choice during intubation in Japan. On the other hand, video laryngoscopes are not as widely used among emergency and intensive care physicians other than anesthesiologists at our hospital. We therefore distributed a questionnaire on video laryngoscopes to 12 physicians not including anesthesiologists from the emergency department and intensive care unit at our hospital. When we asked which intubation device was used as the first choice during endotracheal intubation, all 12 physicians responded that they used the Macintosh laryngoscope, and none used video laryngoscopes. We then asked these physicians whether they were aware of any studies on the usefulness of video laryngoscopy (Airway scope) in cases where intubation is difficult [1] or in cases of restricted cervical spine mobility [2], and found that all 12 physicians knew of such research. The most common reasons for not using video laryngoscopes as the first choice were lack of skill and insufficient experience. When asked whether they would be more tempted to use video laryngoscopes if they received guidance on their use from anesthesiologists, all 12 physicians responded that they would indeed be more tempted to use them. Now that the usefulness of video laryngoscopes has been revealed and the dissemination of these devices has been achieved throughout the field of anaesthesiology, we believe that it is important for anesthesiologists to provide guidance on the use of video laryngoscopes in order to next disseminate these devices throughout the field of emergency and intensive care.

Washing out potassium absorption filters with normal saline after use

The potassium concentration of irradiated red cell bags generally increases during the storage period. When blood products with increased potassium concentrations are administered to patients with renal dysfunctions, there is a high risk of causing hyperkalemia. In these cases, a filter (KPF-4, Kawasumi Laboratories, Tokyo, Japan) to adsorb the potassium in the red cell bags is useful [1, 2]. It has been reported that the filter is effective for use during surgery as large volume blood transfusions are required [3, 4], but it is also useful to patients of renal dysfunctions. The potassium-adsorption filter contains cation exchange resins that exchange sodium and potassium, and thus is able to adsorb and eliminate potassium from the blood products. The filter is extremely convenient and effective, but care is needed after use. When normal saline is used to wash out the filter after the administration of blood products, there is a risk of high administration of potassium to the patient owing to reprecipitation of the adsorbed potassium. We rinsed a filter with approximately 100 ml of normal saline after using 4 units of blood products and disconnect from a patient; when a part of the saline solution was examined, a high concentration of potassium (approximately 9–17 mmol/l) was detected. This danger is listed in the warning section of product information, but many physicians are unaware of this information. Blood transfusion products are precious and limited resources; thus, it is necessary to use them as efficiently as possible. For this reason, after the completion of blood transfusions, normal saline is sometimes added to the blood product remaining in the standard blood transfusion filters and administration lines and administered to the patients. However, when using the potassium-adsorption filter, washing out the filter with normal saline is dangerous. We suggest that care is especially needed not only in the operating room but also in the unit where many patients with severe renal dysfunction are treated.