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We analyze a duopolistic health care market in which a rural public hospital competes against an urban public hospital on medical quality, by using a Hotelling-type spatial competition model extended into a two-region model. We show that the rural public hospital provides excess quality for each unit of medical service as compared to the first-best quality, and the profits of the rural public hospital are lower than those of the urban public hospital because the provision of excess quality requires larger expenditure. In addition, we investigate the impact of the partial (or full) privatization of local public hospitals.

Objective: To develop an ergonomically designed computerized recordkeeping tool for anesthesiologists that allows the clinician to maintain visual contact with the patient while performing recordkeeping., Methods: To simplify the human interface software, we developed two general use software components. All purpose menu type 1 (APM1) was used for entering events using a tree structured menu. APM1 was designed to adapt to the limits of human memory, by using Miller's rule of 7 to guide the input process. APM1 can be considered to be a three-dimensional table list consisting of 7 vertical and 7 horizontal choices, which has further 5 tree-structured divergences. APM1 is also completely configurable by the user. All purpose menu 2 (APM2) was used to implement the system-initiated human interface where the system will prompt the user by voice for each entry. When users touch a key on APM1 and APM2, the system was designed to respond with a voice prompt. A touch-screen was also utilized and designed to fit the anesthesia machine. The screen is equipped with a small speaker for voice response and a microphone for voice recognition. The positions of the screen are adjustable supported by a long flexible limb (85 cm)., Results: After improving the design, systems were assembled for 10 operating rooms. Of the multiple features of the VOCAAR user interface, the following were well accepted by users and employed daily: touch-screen input, and voice response. The noncompulsory use rate was 87% during the initial 2 weeks, increased to 94% after 2 weeks and 100% after two months. The mean sound emission by voice response (n = 10, mean +/- SD) was 8.2 +/- 2.3 dB at the main anesthetist site (35 cm from the speaker mounted on the touch-screen), 2.2 +/- 1.3 dB at the staff site (1.5 m from the touch-screen), which was only audible for anesthesiologist but for surgeon., Discussion: An EARK system was designed to allow the user to maintain visual contact with the patient while performing recordkeeping tasks. The combination of a mobile touch screen and voice response/recognition facilitated the design goals of the system. Although the system has enjoyed universal clinical acceptance, the voice functions remain too limited to satisfy the needs of a completely handsfree user interface. Enhancements to voice recognition technology will offer the potential for improved functionality. Additional research is also needed to better define the relationship between vigilance and visual contact with the patient.

Objective: In order to predict the partial pressure of volatile anesthetics in brain tissue, we developed a pharmacokinetic simulation model suitable for real time application. The accuracy of this model was examined by comparing the predicted values against measured values for blood sampled from the internal jugular vein, which was used as a measure of the partial pressure in the brain., Methods: Our model consists of six compartments: alveoli, arterial blood, a group of vessel-rich organs (VRG), muscle, fat, and venous blood. A volatile anesthetic, sevoflurane partial pressure in each compartment were calculated using the parameters of volume, blood flow, and solubility for each tissue as reported in previous studies. Simulated sevoflurane partial pressures in VRG were considered to reflect those in the brain. We studied 11 patients undergoing elective abdominal surgery or mastectomy. Sevoflurane was maintained at a concentration of 3% (by vaporizer setting) for 25 min. Sampling points were at 0 min (before sevoflurane administration) and 1, 2, 4, 9, 16, and 25 min after the start of inhalation. We measured the sevoflurane partial pressure in inspiratory gas (PI(S)), in end-expiratory gas (PET(S)), in arterial blood (Pa(S)), and in internal jugular vein blood (Pj(S)). These values were compared against those for the simulated brain (PB(S)sim)., Results: The sevoflurane partial pressures increased, in order from least rapid to most rapid, as follows: Pj(S), PB(S)sim, Pa(S), PET(S), and PI(S). The differences between Pj(S) and PB(S)sim were significantly smaller than those between Pj(S) and PET(S) at all sampling points. PB(S)sim did not differ significantly from Pj(S) at any sampling points after 4 min of inhalation, while PET(S) differed significantly from Pj(S) at all sampling points., Conclusion: We conclude that our model is clinically useful for predicting sevoflurane partial pressure in the brain, assuming that Pj(S) reflects the sevoflurane partial pressure in the brain.

Tension pneumoperitoneum may force gas into a small injured vessel if the opening is kept patent by surrounding tissues. However, the amount of carbon dioxide (CO2) that penetrates through injured or noninjured peritoneum has not been systematically determined. In 25 patients undergoing elective laparoscopic ultrasonography and cholecystectomy, CO2 output (VCO2) and O2 uptake (VO2) were measured at baseline and during anesthesia, pneumoperitoneum, laparoscopic surgical procedure (Surgery), and after hemostasis of the surgical field (Postsurgery). Before anesthesia, VCO2/BSA and VO2/BSA were 97.7 +/- 11.3 and 116.0 +/- 10.0 ml x min(-1) x m(-2), respectively. During anesthesia, they fell to 72.3 +/- 6.0 and 89.8 +/- 7.6 ml x min(-1) x m(-2), respectively (p < 0.05). VCO2/BSA increased to 96.0 +/- 11.1 at pneumoperitoneum (p < 0.05) and increased further to 126.1 +/- 11.0 ml x min(-1) x m(-2) at Surgery. It fell to 111.7 +/- 10.9 ml x min(-1) x m(-2) Postsurgery. VO2/BSA remained unchanged during pneumoperitoneum. Minute volume increased from 2.24 +/- 0.20 in anesthesia to 2.89 +/- 0.25, 4.01 +/- 0.32, and 3.46 +/- 0.28 L x min(-1) x m(-2) during pneumoperitoneum, Surgery, and Postsurgery, respectively, to maintain PaCO2. We conclude that the amount of CO2 absorbed following pneumoperitoneum prior to surgery is lower than that during Surgery or Postsurgery. The amount of CO2 absorbed through the surgical field was 2.3 times higher than that through the nonsurgical field while that from the peritoneum after hemostasis of surgical field was 1.6 times higher.

Critically ill or anesthetized patients commonly receive pump-driven intravenous infusions of potent, fast-acting, short half-life medications for managing hemodynamics. Stepwise dosing, e.g. over 3-5 min, adjusts physiologic responses. Flow rates range from < 0.1 to > 30 ml/h, depending on pump type (large volume, syringe) and drug concentration. Most drugs are formulated in aqueous solutions. Hydrophobic drugs are formulated as lipid emulsions. Do the physical and chemical properties of emulsions impact delivery compared to aqueous solutions? Does stepwise dose titration by the pump correlate with predicted plasma concentrations? Precise, gravimetric, flow rate measurement compared delivery of a 20% lipid emulsion (LE) and 0.9% saline (NS) using different pump types and flow rates. We measured stepwise delivery and then computed predicted plasma concentrations following stepwise dose titration. We measured the pharmacokinetic coefficient of short-term variation, (PK-CV), to assess pump performance. LE and NS had similar mean flow rates in stepwise rate increments and decrements between 0.5 and 32 ml/h and continuous flows 0.5 and 5 ml/h. Pharmacokinetic computation predictions suggest delayed achievement of intended plasma levels following dose titrations. Syringe pumps exhibited smaller variations in PK-CV than large volume pumps. Pump-driven deliveries of lipid emulsion and aqueous solution behave similarly. At low flow rates we observed large flow rate variability differences between pump types showing they may not be interchangeable. PK-CV analysis provides a quantitative tool to assess infusion pump performance. Drug plasma concentrations may lag behind intent of pump dose titration., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Purpose: Different organs have different autoregulatory capacities for blood pressure changes and/or circulatory volume changes. This study assessed the autoregulation of the stomach, liver, kidney and skeletal muscle, under baseline, hypovolemic, and post-fluid-resuscitation conditions using near-infrared spectroscopy (NIRS)., Methods: Ten pigs (bodyweight 24.5 ± 0.5 kg) were anesthetized with 2.5% isoflurane and administered 0.5, 1, 2 and 5 µg kg - 1  min - 1 of phenylephrine at 10-min intervals, followed by similar stepwise infusion of sodium nitroprusside (SNP) to induce a wide range of mean arterial pressures (MAPs). A 600-ml bleed was induced to create the hypovolemic condition, and only phenylephrine was re-administered. Hydroxyethyl starch (600 ml) was infused to create the post-fluid-resuscitation condition, and phenylephrine and SNP were re-administered. Average relationships between mean arterial pressure (MAP) and each tissue oxygenation index (TOI) were assessed, and the individual relationships were evaluated based on the correlation coefficients between MAP and TOI during each vasoactive drug infusion., Results: Based on the evaluation using each TOI as a substitute of blood flow, the kidney autoregulation was robust, similar to muscle, but had a prominent lower limit. The stomach had weaker autoregulation than the kidney and muscle. The liver had no autoregulation. The kidney TOI showed 2-fold greater changes in response to volume condition changes than the stomach and liver TOIs., Conclusion: In our NIRS-based assessment of autoregulatory capacity, the liver oxygenation is highly blood pressure dependent, and the kidney is highly susceptible and the skeletal muscle is highly tolerable to low blood pressure and volume loss., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Author(s): Matsuyuki Doi [sup.1], Naoyuki Hirata [sup.2], Toshiyasu Suzuki [sup.3], Hiroshi Morisaki [sup.4], Hiroshi Morimatsu [sup.5], Atsuhiro Sakamoto [sup.6] Author Affiliations: (1) grid.471533.7, 0000 0004 1773 3964, Department of Anesthesiology [...], Purpose Remimazolam, an ultra-short-acting benzodiazepine sedative is equally effective as propofol in induction and maintenance of general anesthesia with improved hemodynamic stability in American Society of Anesthesiologists (ASA) Class I and II patients. This trial investigated remimazolam's efficacy and safety in vulnerable patients (ASA Class III) undergoing elective general surgery. Methods A multicenter, randomized, double-blind, parallel-group trial in 67 adult surgical patients undergoing general anesthesia with two remimazolam induction doses (6 mg kg.sup.-1 h.sup.-1-group A and 12 mg kg.sup.-1 h.sup.-1-group B) has been conducted in 6 trials sites in Japan. Remimazolam was infused up to 2 mg kg.sup.-1 h.sup.-1 for maintenance of anesthesia in both groups. Results The functional anesthetic capability of the investigated drug was 100% in both arms. The mean time to loss of consciousness (LoC) was significantly shorter in group B (81.7 s) compared to group A (97.2 s), p = 0.0139. The mean bispectral index (BIS) value during maintenance of anesthesia ranged from 46.0 to 68.0 and from 44.7 to 67.5 in group A and B, respectively. There was no statistically significant difference between the remimazolam arms concerning the incidence of blood pressure (BP) decrease (67.7% in group B vs. 54.8% in group A), recovery profile or the incidence or severity of adverse events (AEs) or adverse drug reactions (ADRs). Conclusion Both induction regimens (6 and 12 mg kg.sup.-1 h.sup.-1) were equally efficacious and safe in surgical patients ASA Class III. A significantly shorter time to LoC was observed with the higher remimazolam dosage. Clinical trial registration This trial is registered with the Japan Pharmaceutical Information Center-Clinical Trials Information (JapicCTI). JapicCTI number: 121977.

Author(s): Tsunehisa Sato [sup.1], Soichiro Mimuro [sup.1], Takasumi Katoh [sup.1], Tadayoshi Kurita [sup.1], Sang Kien Truong [sup.1], Kensuke Kobayashi [sup.1], Hiroshi Makino [sup.1], Matsuyuki Doi [sup.1], Yoshiki Nakajima [sup.1] Author [...], Purpose Hydrogen gas (H.sub.2) inhalation improved the survival rate of hemorrhagic shock. However, its mechanisms are unknown. We hypothesized that H.sub.2 protected the endothelial glycocalyx during hemorrhagic shock and prolonged survival time. Methods 83 Sprague-Dawley rats were anesthetized with isoflurane. The animals were randomly assigned to 5 groups: room air with no shock, 1.2% H.sub.2 with no shock, room air with shock (Control-S), 1.2% H.sub.2 with shock (H.sub.21.2%-S), and 3.0% H.sub.2 with shock (H.sub.23.0%-S). Shock groups were bled to a mean arterial pressure of 30-35 mmHg and held for 60 min, then resuscitated with normal saline at fourfold the amount of the shed blood volume. Results The syndecan-1 level was significantly lower in the H.sub.21.2%-S [8.3 ± 6.6 ng/ml; P = 0.01; 95% confidence interval (CI), 3.2-35.8] than in the Control-S (27.9 ± 17.0 ng/ml). The endothelial glycocalyx was significantly thicker in the H.sub.21.2%-S (0.15 ± 0.02 [micro]m; P = 0.007; 95% CI, 0.02-0.2) than in the Control-S (0.06 ± 0.02 [micro]m). The survival time was longer in the H.sub.21.2%-S (327 ± 67 min, P = 0.0160) than in the Control-S (246 ± 69 min). The hemoglobin level was significantly lower in the H.sub.21.2%-S (9.4 ± 0.5 g/dl; P = 0.0034; 95% CI, 0.6-2.9) than in the Control-S (11.1 ± 0.8 g/dl). However, the H.sub.23.0%-S was not significant. Conclusions Inhalation of 1.2% H.sub.2 gas protected the endothelial glycocalyx and prolonged survival time during hemorrhagic shock. Therapeutic efficacy might vary depending on the concentration.

Introduction Sevoflurane is widely used in clinical anesthesia because of its relative lack of airway irritation or myocardial suppression effects. It has rapid induction and emergence characteristics compared with other [...], Purpose Sevoflurane, with a relative low blood-gas partition coefficient, is an ideal anesthetic to achieve rapid offset and recovery from general anesthesia. This study will determine the profiles of four concentration-time curves to characterize the pharmacokinetics of sevoflurane elimination. Methods Eight patients (aged 54-76 years) undergoing coronary arterial bypass grafting surgery were enrolled in this study. At the end of surgery, anesthetic gas and blood were sampled 20 min before and after stopping sevoflurane administration, with prior maintenance of a fixed 5% inspired sevoflurane (CIsev) in 6 L/min oxygen flow for 60 min before the cessation of sevoflurane administration for the subsequent 20 min elimination. An infrared analyzer was used to determine both CIsev and end-tidal sevoflurane (CEsev). The sevoflurane concentrations in the internal jugular-bulb (Jsev), arterial (Asev) and pulmonary arterial blood (PAsev) were analyzed by gas chromatography, and cardiac output was measured using an Opti-Q pulmonary artery catheter. Results A bi-exponential decay function was the best fit for the CEsev, Jsev, Asev, and PAsev time curves. There were two distinct components, the initial 5-min fast or distribution phase and the subsequent 15-min slow or elimination phase. Before cessation of the sevoflurane supplement, the step-down concentration of sevoflurane was listed in the following order: CIsev > CEsev > Asev [??] Jsev > PAsev. During the elimination phase, the fastest decay occurred in CEsev, followed by Jsev, Asev and PAsev. Therefore, a reverse step-down pattern was observed (PAsev > Asev [??] Jsev > CEsev) after 20 min. The ratio of Asev to CEsev was 89% at baseline before stopping sevoflurane administration, but the ratio of Asev to CEsev increased to 128% at the twentieth min of the sevoflurane elimination phase. Conclusions During elimination, the initial washout of sevoflurane from the functional residual capacity of the lungs was reflected in the fast component of the CEsev, Jsev, Asev, and PAsev time curves. In contrast, the slow component was dominated by the tangible effects of the physiological membrane barriers, such as the alveoli-pulmonary capillary and blood-brain barriers. Keywords Anesthetic * Sevoflurane * Pharmacokinetics * Elimination

Purpose To validate a novel method of ultrasound dilution (COstatus.sup.®; Transonic Systems, Ithaca, NY) for measuring cardiac output in paediatric patients after biventricular repair of congenital heart disease. Methods Children undergoing biventricular repair of congenital heart disease were prospectively identified. Patients with significant intracardiac shunts were excluded. Postoperative cardiac output was measured by ultrasound dilution (COud) and concurrently calculated by the Fick equation (COrms) using measured oxygen consumption by respiratory mass spectrometry. Results Thirty-five patients were studied generating 66 individual data sets. Subjects had a median (interquartile range) age of 147 days (11, 216), weight of 4.98 kg (3.78, 6.90) and body surface area of 0.28 m.sup.2 (0.22, 0.34). Of the patients, 66 % had peripheral arterial catheters and 34 % had femoral cannulation; peripheral arterial lines accounted for 6/8 of unsuccessful studies due to inability to generate sufficient flow. The site of the central venous cannula did not impact the feasibility of completing the study. A mean bias of 0.00 L/min [2 standard deviation (SD) ± 0.76 L/min] between COud and COrms was found with a percentage error of 97 %. When comparing cardiac index, bias increased to 0.13 L/min/m.sup.2 (2SD ± 2.16 L/min/m.sup.2). Conclusions Cardiac output by ultrasound dilution showed low bias with wide limits of agreement when compared to measurement derived by the Fick equation. Although measurements through central and peripheral arterial lines were completed with minimal difficulties in the majority of patients, the application of COstatus.sup.® in neonates with low body surface area may be limited., Author(s): Alejandro A. Floh [sup.1], Gustavo La Rotta [sup.1], Julius Z. Wermelt [sup.1], Patricia Bastero-Miñón [sup.1], V. Ben Sivarajan [sup.1], Tilman Humpl [sup.1] Author Affiliations: (1) grid.42327.30, 0000000404739646, Department of [...]

Introduction Theoretically, the passage of a volatile anesthetic from the alveolar space into the bloodstream depends on several factors, including concentration of the inspired anesthetic, its blood/gas partition coefficient, ventilation [...], Purpose We investigated whether ventilation volumes affected arterial blood sevoflurane concentration ([A.sub.sev]) and its uptake into the body during general anesthesia. Methods Thirty female patients undergoing elective gynecologic surgery were randomly allocated into three groups: hyperventilation, normal ventilation, and hypoventilation. Inspiratory ([CI.sub.sev]) and end-tidal ([sub.sev]) sevoflurane concentrations were routinely measured by infrared analysis, and [A.sub.sev] were analyzed by gas chromatography for 40 min after intubation. Cardiac index and total peripheral vascular resistance were measured with a Finometer. Results During the first 10 min after sevoflurane administration, [A.sub.sev] in the hyperventilation group was the highest and differed significantly from those in the normal ventilation group, followed by those in the hypoventilation group. In addition, hyperventilation significantly increased the slope of [A.sub.sev] over time in the first 5 min, but there were no differences in slopes in the 5-10, 10-20, and 20-40 min periods, which indicates no difference in sevoflurane bodily uptake among the three groups after 5 min. Conclusion Hyperventilation accelerated the rate of [A.sub.sev] increase immediately after sevoflurane administration, which was time dependent with respect to different alveolar ventilation levels. Keywords Sevoflurane * Pharmacokinetics * Ventilation * Arterial blood * End tidal

Purpose To compare cardiac output (CO) and blood volumes measured by COstatus.sup.® (Transonic Systems Inc., NY, USA) versus PiCCO (Philips IntelliVue MP40 with PiCCO-technology module M3012A#10, Netherlands) in adult ICU patients. Methods This was a prospective single-center study. Each of the 30 patients studied received a 5-Fr Pulsiocath femoral arterial and a standard central venous catheter. Twenty ml of iced 5% dextrose solution was injected for PiCCO measurements. For COstatus measurements, an extracorporeal arteriovenous loop, with two sensors placed on it, was connected between the Pulsiocath femoral arterial and central venous catheters. Blood was circulated through this loop at 12 ml/min for 5-8 min using a pump. Twenty ml of warm saline was injected into the venous side for measurements. For each method, three injections were averaged for comparison. Results A good agreement for measured CO (range 3.65-16.3 l/min) with a percentage error of 20% was observed, with r = 0.95, bias = -0.037 l/min. PiCCO's global end-diastolic volume (GEDV) was 2.5 times larger than the analogous COstatus's total end-diastolic volume (TEDV) [TEDV = 0.28 x GEDV + 176 ml]. PiCCO's intrathoracic blood volume (ITBV) was larger than the analogous COstatus's central blood volume (CBV) [CBV = 0.73 x (ITBV) +78 ml]. Conclusions CO measured by COstatus was found to be equivalent and hence interchangeable with PiCCO in this study population. COstatus blood volumes were found to be within the expected physiological range whilst PiCCO blood volumes were significantly higher, which was also observed in other studies. Future studies using 3D echo/MRI are required to validate these blood volumes., Author(s): Gennady Galstyan [sup.1], Mychaylo Bychinin [sup.1], Mikael Alexanyan [sup.1], Vladimir Gorodetsky [sup.1] Author Affiliations: (1) grid.477614.7, Department of Intensive Care, National Hematology Research Center, , Moscow, Russian Federation Introduction [...]

Introduction Beta-blocker therapy is widely known to reduce perioperative cardiovascular complications [1, 2]. Recent guidelines from the American College of Cardiology/American Heart Association [2] recommend the use of beta-blockers in [...], According to the guidelines of the American College of Cardiology/American Heart Association 2006 for perioperative cardiovascular evaluation for non-cardiac surgery, beta-blocker therapy should be considered for high-risk individuals undergoing vascular surgery or high-and intermediate-risk patients undergoing non-cardiac surgery. This guideline might induce physicians to increasingly use beta-blockers in the hope of preventing perioperative cardiac complications. However, beta-blockers have potential beneficial effects outside the prevention of cardiac events. In addition to reducing anesthetic and analgesic requirements during the perioperative period, beta-blockers have neuroprotective effects in patients with brain trauma and possible effectiveness in the management of intraoperative awareness-induced posttraumatic stress disorder. Moreover, intrathecal administration of beta-blockers may have antinociceptive effects. Physicians need to bear in mind the benefits of beta-blockers for purposes other than preventing cardiac events when applied in the perioperative period, and they should be familiar with the pharmacodynamics and risk-benefit ratio with their use. This review focuses on possible extracardiac indications of beta-blockers. Keywords Anesthetic requirements * Beta-blockers * Immunomodulation * Intraoperative