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Ventilation in the prone position improves the prognosis of patients with severe acute respiratory distress syndrome (ARDS). Contraindications to ventilation in this position include unstable systemic circulation. Only a few reports exist on the effects of prone ventilation in respiratory failure on systemic circulation. This animal study compared systemic hemodynamic changes between supine and prone positions in anesthetized rabbits under acute systemic hypoxia (breathing 15% O(2)). Cardiac output and the systemic O(2) extraction ratio increased under the hypoxia, but only in the supine group. Besides, the rate pressure product was higher in the prone group than in the supine group. This study showed that prone ventilation increases myocardial O(2) consumption and suppresses compensatory mechanisms to maintain aerobic metabolism during systemic hypoxia. First of all, it will be necessary to examine the effect of prone ventilation on the O(2) supply-demand balance in the ARDS model.

BACKGROUND: Breathing during a marathon is often empirically conducted in a so-called “2:2 breathing rhythm,” which is based on a four-phase cycle, consisting of the 1st and 2nd inspiratory and the 1st and 2nd expiratory phases. We developed a prototype ventilator that can perform intermittent positive pressure ventilation, mimicking the breathing cycle of the 2:2 breathing rhythm. This mode of ventilation was named the marathoners’ breathing rhythm ventilation (MBV). We hypothesized that MBV may have a lung protective effect. METHODS: We examined the effects of the MBV on the pulmonary pre-edema model in isolated perfused rabbit lungs. The pulmonary pre-edema state was induced using bloodless perfusate with low colloid osmotic pressure. The 14 isolated rabbit lung preparations were randomly divided into the conventional mechanical ventilation (CMV) group and MBV group, (both had an inspiratory/expiratory ratio of 1/1). In the CMV group, seven rabbit lungs were ventilated using the Harvard Ventilator 683 with a tidal volume (TV) of 8 mL/kg, a respiratory rate (RR) of 30 cycles/min, and a positive end-expiratory pressure (PEEP) of 2 cmH(2)O for 60 min. In the MBV group, seven rabbit lungs were ventilated using the prototype ventilator with a TV of 6 mL/kg, an RR of 30 cycles/min, and a PEEP of 4 cmH(2)O (first step) and 2 cmH(2)O (second step) for 60 min. The time allocation of the MBV for one cycle was 0.3 s for each of the 1st and 2nd inspiratory and expiratory phases with 0.2 s of intermittent resting between each phase. RESULTS: Peak airway pressure and lung wet-to-dry ratio after 60 min of ventilation were lower in the MBV group than in the CMV group. CONCLUSION: MBV was considered to have a lung-protective effect compared to CMV.

Small gauze is used in laparoscopy; therefore, retention of gauze can occur. We experienced a case of retention of a radiopaque thread that ruptured from a piece of gauze and moved into the peritoneum during a scheduled laparoscopy. The patient was a 65-year-old woman who underwent laparoscopic-assisted transverse colon resection for transverse colon cancer. A commercial gauze commonly used for laparoscopy was used during the surgery. To more easily identify the gauze during surgery, radiopaque threads extending up to 3.0 cm from the two diagonal corners of the gauze body were attached. After wound closure, radiography showed a radiopaque thread-like substance in the abdomen. Minor laparotomy was performed, and part of the radiopaque thread was discovered. On postoperative day 22, the patient was in remission and discharged.

Background Isoflurane and sevoflurane protect lungs with ischemia–reperfusion (IR) injury. We examined the influence of desflurane on IR lung injury using isolated rabbit lungs perfused with a physiological salt solution. Methods The isolated lungs were divided into three groups: IR, desflurane-treated ischemia–reperfusion (DES-IR), and ventilation/perfusion-continued control (Cont) groups (n = 6 per group). In the DES-IR group, inhalation of desflurane at 1 minimum alveolar concentration (MAC) was conducted in a stable 30-min phase. In the IR and DES-IR groups, ventilation/perfusion was stopped for 75 min after the stable phase. Subsequently, they were resumed. Each lung was placed on a balance, and weighed. Weight changes were measured serially throughout this experiment. The coefficient of filtration (Kfc) was determined immediately before ischemia and 60 min after reperfusion. Furthermore, bronchoalveolar lavage fluid (BALF) was collected from the right bronchus at the completion of the experiment. After the completion of the experiment, the left lung was dried, and the lung wet-to-dry weight ratio (W/D) was calculated. Results The Kfc values at 60 min after perfusion were 0.40 ± 0.13 ml/min/mmHg/100 g in the DES-IR group, 0.26 ± 0.07 ml/min/mmHg/100 g in the IR group, and 0.22 ± 0.08 (mean ± SD) ml/mmHg/100 g in the Cont group. In the DES-IR group, the Kfc at 60 min after the start of reperfusion was significantly higher than in the other groups. In the DES-IR group, W/D was significantly higher than in the Cont group. In the DES-IR group, the BALF concentrations of nitric oxide metabolites were significantly higher than in the other groups. In the DES-IR group, the total amount of vascular endothelial growth factor in BALF was significantly higher than in the Cont group. Conclusions The pre-inhalation of desflurane at 1 MAC exacerbates pulmonary IR injury in isolated/perfused rabbit lungs.

Phosphoenolpyruvate (PEP) is an intermediate metabolite of the glycolytic pathway and an in vivo high-energy phosphate compound. We have examined the protective effects of PEP on ischemia–reperfusion lung injury in isolated rabbits lungs perfused with a physiological salt solution. The lungs were divided into three treatment groups: (1) ischemia–reperfusion (IR), (2) ischemia–reperfusion with PEP treatment (PEP-IR), in which 1 mM PEP was pre-administered into the perfusate during the stable period, and (3) ventilation–perfusion continued without interruption (Cont). In the IR and PEP-IR groups, ventilation–perfusion was discontinued for about 60 min after a 30-min stable period and then restarted. The capillary filtration coefficients (K fc) and pyruvate concentration in the perfusate were determined immediately before ischemia and 30 and 60 min after reperfusion. The left lungs were dried at the end of the experiment to calculate the tissue wet-to-dry weight ratio (W/D). The K fc values after reperfusion were significantly higher in the IR group than in the other two groups. Pyruvate concentrations were significantly higher at three time-points in the PEP-IR group than in the other two groups. The W/D was significantly higher in the IR group than in the other two groups. Based on these results, we conclude that the administration of PEP prior to lung ischemia alleviates lung ischemia–reperfusion injury.

We propose an omnidirectional three-dimensional (3D) display system. This is a tool for communication around a 3D image between a small number of people. This 3D display consists of multiple basic 3D display units. Each basic 3D display unit consists of a projector and a curved HOE lens array sheets. The projector is located on the center of the curvature of the curved HOE lens array, and it projects light rays on the curved HOE lens array with ascending vertical angle 45-degree. Projected light rays are reflected and reconstruct the 3D image over the center of the curvature by the curved HOE lens array. In this method, even though the viewing angle of each HOE lens does not increase, the viewing angle of the 3D image by the curved HOE lens array can be increased. To verify the effectiveness of the proposed method, we constructed the prototype basic 3D unit. The viewing angle of a 3D image was 44-degree. Therefore, the viewing angle was increased by the proposed method compared to 17-degree by the conventional flat HOE lens array. This paper describes the principle of proposed 3D display system, and also describes the experimental results.

The role of volatile anaesthetics on nitric oxide (NO)-dependent relaxation is unclear in the pulmonary circulation. We examined the effects of isoflurane on NO-dependent relaxation in isolated perfused rabbit lungs.Eighteen rabbit lungs were perfused in a constant-flow recirculation manner. In study 1 (n = 12), acetylcholine (ACh, 4 x 10(-10)-10(-8) M) or nitroglycerine (NTG, 6 x 10(-10)-10(-8) M) was cumulatively injected into the pulmonary artery in the absence or presence of isoflurane (1, 2 MAC). In study 2 (n = 6), ACh was injected as in study 1 in the presence or absence of N omega-nitro-L-arginine methyl ester (L-NAME, 100 microM), an NO synthesis blocker. In all experiments, indomethacin was administered to prevent formation of vasoactive prostanoid metabolites, and the pulmonary vessels were preconstricted with prostaglandin F2 alpha (PGF2 alpha) infused before ACh or NTG injection. The ACh- or NTG-induced relaxation was expressed as % decrease in PGF2 alpha preconstriction.Isoflurane at 2 MAC attenuated the dose-dependent relaxation to ACh at doses of 4 x 10(-9) M and 4 x 10(-8) M from 27.8 +/- 4.3% and 38.8 +/- 5.3% to 17.0 +/- 3.5% and 25.5 +/- 4.9%, respectively (P0.05). Isoflurane did not change the dose-dependent relaxation to NTG and L-NAME abolished the ACh-induced relaxation.Isoflurane inhibited NO-dependent relaxation in the pulmonary circulation at a site distal to the endothelial cell receptor-mediated responses but proximal to guanylate cyclase activation of vascular smooth muscle. Acetylcholine-induced relaxation in isolated perfused rabbit lungs was regulated primarily by NO.