General anesthesia for surgical treatment of urethral obstruction in nine goats

Nine pygmy goats underwent surgical treatment for obstructive urolithiasis in a period of six months. In two cases, (second) revision surgery was necessary resulting in a total of twelve procedures under general anesthesia. Different anesthetic protocols were applied: analgesia was provided by an opioid (12/12) combined with either benzodiazepine (10/12) or an alpha-2 agonist (2/12). Anesthesia was induced with propofol (10/12) or ketamine (2/12) and maintained with isoflurane (8/12) or sevoflurane (4/12) in oxygen in a semi-closed circle system with continuous monitoring during anesthesia. Minor complications were mild bradycardia (4/12), hypotension (3/12), metabolic acidosis (1/12) and hypothermia (12/12). In four cases, epidural anesthesia was performed; in one of those four cases, severe complications developed (paralysis, 1/4). The goat was euthanized later. Although urethral obstruction increases the risk of general anesthesia, the selection of an appropriate anesthetic protocol, adequate preoperative examination/ preparation and detailed monitoring throughout anesthesia reduced the incidence of severe complications in this case series.

Study of Power Generation System Based on Black Smokers

The OTEC system of the paper studying is different with the traditional OTEC system, which takes the marine geothermal energy (black smokers) as the heat source, takes cold seawater of deep sea as the cold source. The paper analyzes and calculates some parameters of open-circle system which uses water vapor as the working fluid and the closed-circle system which uses pure ammonia as the working fluid, those parameters include thermal efficiency, heat load of condenser and evaporator, pump power consumption, and the net power output. The results show that: with the closed-circle system which uses pure ammonia as the working fluid, the large power consumption of hot water pump is the biggest problem for the open-circle system, besides reducing the temperature of hot fluid and increasing the flash pressure are disadvantageous for open-circle system; but water vapor as the working fluid helps to reduce the load of condenser and evaporator, which is very advantageous for heat exchanger design.

Effect of Fresh Gas Flow on Isoflurane Concentrations during Low-flow Anaesthesia

The effect of fresh gas flow (FGF) on isoflurane concentrations at given vaporizer settings during low-flow anaesthesia was investigated. Ninety patients (American Society of Anaesthesiologists physical status I or II) were randomly allocated to three groups (FGF 1 l/min, FGF 2 l/min and FGF 4 l/min). Anaesthesia was maintained for 10 min with vaporizer setting isoflurane 2 vol% and FGF 4 l/min for full-tissue anaesthetic uptake in a semi-closed circle system. Low-flow anaesthesia was maintained for 20 min with end-tidal isoflurane 1.5 vol% and FGF 2 l/min. FGF was then changed to FGF 1 l/min, FGF 2 l/min or FGF 4 l/min. Measurements during the 20-min period showed that inspired and end-tidal isoflurane concentrations decreased in the FGF 1-l/min group but increased in the FGF 4-l/min group compared with baseline values. No haemodynamic changes were observed. Monitoring of anaesthetic concentrations and appropriate control of vaporizer settings are necessary during low-flow anaesthesia.