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Noninvasive blood-pressure measurement device and pulse oximeter are important for patient monitoring. When these are placed on the same side, cuff inflation sometimes causes measurement failure by pulse oximeter.The present study aimed to compare the pulse oximeter alarm frequency and pulse-wave disappearance duration between noninvasive blood-pressure measurement using the deflation method and that using the linear inflation method.The study included 10 healthy subjects. The cuff for automatic sphygmomanometer was wrapped on one side of the upper arm and for pulse oximeter was attached to the thumb of the same side of upper limbs.The alarm frequency was 0 and 26% using the linear inflation and the deflation methods, respectively. Additionally, the pulse-wave disappearance duration was significantly longer using the deflation method than that using the linear inflation method (10.0 ± 1.5 vs 1.7 ± 0.8 s). With the linear inflation method, this duration was or less 3 s. In the deflation method, an excess pressure of 40 mmHg was used, which caused the alarm to turn on. Additionally, the heart rate was found to influence the alarm occurrence during measurement using the deflation method.Heart rate may influence alarm occurrence during blood-pressure measurement using the step deflation method. Using the linear inflation method, the risks of alarm occurrence and measurement failure are low, even when the pulse oximeter and blood-pressure measurement cuffs are installed on the same side, suggesting that this method is suitable for clinical use.

Background Total hemoglobin (tHb) measurement is indispensable for determining the patient’s condition (hemorrhagic vs. ischemic) and need for blood transfusion. Conductivity- and absorbance-based measurement methods are used for blood gas analysis of tHb. For conductivity-based measurement, tHb is calculated after converting blood conductivity into a hematocrit value, whereas absorbance measurement is based on light absorbance after red blood cell hemolysis. Due to changes in plasma electrolytes and hemolysis, there is a possibility that conductivity- and absorbance-based measurement methods may cause a difference in tHb. Methods In this study, test samples with controlled electrolyte changes and hemolysis were created by adding sodium chloride, distilled water or hemolytic blood to blood samples collected from healthy volunteers, and tHb values were compared between both methods. Results Conductivity-based measurement revealed reduced tHb value (from 15.49 to 13.05 g/dl) following the addition of 10% sodium chloride, which was also reduced by the addition of hemolysate. Conversely, the addition of distilled water significantly increased tHb value than the expected value. In the absorbance method, there was no significant change in tHb value due to electrolyte change or hemolysis. Conclusions We have to recognize unexpected conductivity changes occur at all times when tHb is measured via conductivity- and absorbance-based measurement methods. The absorbance method should be used when measuring tHb in patients with expected blood conductivity changes. However, when using this method, the added contribution of hemoglobin from hemolytic erythrocytes lacking oxygen carrying capacity must be considered. We recognize that discrepancy can occur between conductivity- and absorbance-based measurement methods when tHb is measured.

The characteristics of electroencephalogram (EEG) profiles under general anesthesia may depend on age and type of anesthetic. This study investigated age-related differences in EEG waveforms between three inhalational anesthetics used at the same minimum alveolar concentration (MAC), which indicates the level of analgesia. Patients with American Society of Anesthesiologists physical status I–II were divided into three groups according to age: pediatric (≦ 15 years); adult (16–64 years); and elderly (≧ 65 years). Each group was divided into three subgroups according to the inhalational anesthetic used: sevoflurane, isoflurane, and desflurane. Anesthesia was maintained at 1 MAC, followed by assessment of 95% spectral edge frequency (SEF95) values and amplitude of EEG waveform. The 3 age groups comprised a total of 180 patients. The mean (± SD) EEG waveform amplitude and SEF95 values for sevoflurane in the pediatric, adult, and elderly age groups, respectively, were: 32.9 ± 2.9 µV and 16.7 ± 2.4 Hz; 16.4 ± 3.6 µV and 12.2 ± 1.3 Hz; and 11.0 ± 2.1 µV and 13.6 ± 1.6 Hz. EEG waveform amplitude and SEF95 values were significantly higher in the pediatric group than in the other groups. SEF95 value was higher in the elderly group than in the adult group. Similar results were obtained for isoflurane and desflurane. The amplitude of the EEG waveform and SEF95 values varied with age, even at the same analgesic state in patients under general anesthesia. This age-dependent change in EEG waveform was observed for all three inhalational anesthetics, and should be considered in procedures requiring general anesthesia.

Background Cardiopulmonary resuscitation (CPR) requires immediate start of manual chest compression (MCC) and defibrillation as soon as possible. During dental surgery, CPR could be started in the dental chair considering difficulty to move the patient from the dental chair to the floor. However, all types of dental chairs are not stable for MCC. We previously developed a procedure to stabilize a dental chair by using a stool. EUROPEAN RESUSCITATION COUNCIL (ERC) guideline 2015 adopted our procedure when cardiac arrest during dental surgery. The objective of this study was to verify the efficacy of a stool as a stabilizer in different types of dental chairs. Methods Three health care providers participated in this study, and 8 kinds of dental chairs were examined. MCC were performed on a manikin that was laid on the backrest of a dental chair. A stool was placed under the backrest to stabilize the dental chair. The vertical displacement of the backrest by MCC was recorded by a camcorder and measured by millimeter. Next, the vertical displacement of the backrest by MCC were compared between with and without a stool. Results In all 8 dental chairs, the method by using a stool significantly reduced the vertical displacements of the backrest by during MCC. The reduction ratio (mean [interquartile range]) varied between nearly 27 [20] and 87 [5] %. In the largest stabilization case, the displacement was 3.5 [0.5] mm with a stool versus 26 [5.5] mm without a stool (p

Objectives: Cardiopulmonary resuscitation (CPR) requires immediate start of external chest compression (ECC) and cardioversion as soon as possible. During dental surgery, CPR should be started in the dental chair considering difficulty to move the patient from the dental chair to the floor. However, all types of dental chairs are not stable for ECC. We previously developed a procedure to stabilize a dental chair by using a stool. ERC guideline 2015 adopted our procedure when cardiac arrest during dental surgery. The objective of this study was to verify the efficacy of a stool as a stabilizer in different types of dental chairs. Materials and methods: Three health care providers participated in this study, and 8 dental chairs were examined. ECC were performed on a manikin that was laid on the backrest of a dental chair. A stool was placed under the backrest to stabilize the dental chair. The vertical displacement of the backrest by ECC were compared between with and without a stool, and recorded by a camcorder. Results: In all 8 dental chairs, the method by using a stool significantly reduced the vertical displacements of the backrest by ECC. The reduction ratios were between nearly 39~85%, although it was different by chairs. Conclusions: Our procedure to stabilize dental chairs by using a stool significantly reduced the displacement of a backrest against ECC in all chairs. Clinical relevance: Effective ECC could be performed in dental chairs by using a stool when sudden cardiac arrest occurs during dental surgery.

Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE™, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and their frequency characteristics were tested with or without ROSE™. The natural frequency and damping coefficient of each kit were obtained using frequency characteristics analysis software and evaluated by plotting them on the Gardner’s chart. By inserting a planecta port, the natural frequency markedly decreased in both the FloTrac sensor kit (from 40 to 22 Hz) and the DTXplus transducer kit (from 35 to 22 Hz). In both kits with one planecta port, the damping coefficient markedly increased by insertion of ROSE™ from 0.2 to 0.5, optimising frequency characteristics. In both kits with two planecta ports, however, the natural frequency decreased from 22 to 12 Hz. The damping coefficient increased from 0.2 to 0.8 by insertion of ROSE™; however, optimisation was not achieved even by ROSE™ insertion. Planecta ports decrease the natural frequency of the kit. ROSE™ is useful to optimise the frequency characteristics in the kits without or with one planecta port. However, optimisation is difficult with two or more planecta ports, even with the ROSE™ device.