The values of cardiac output were statistically comparable between the groups. Therefore, electrical velocimetry is a suitable method to evaluate haemodynamic variables with clinically acceptable accuracy.

No abstract

Middle cerebral artery occlusion (MCAO) models have become well established as the most suitable way to simulate stroke in experimental studies. The high variability in the size of the resulting infarct due to filament composition, rodent strain and vessel anatomy makes the setup of such models very complex. Beside controllable variables of homeostasis, the choice of anesthetics and the grade of ischemia and reperfusion played a major role for extent of neurological injury. Transient MCAO was induced during either isoflurane or ketamine/xylazine (ket/xyl) anesthesia with simultaneously measurement of cerebral blood flow (CBF) in 60 male Wistar rats (380-420 g). Neurological injury was quantified after 24 h. Isoflurane compared with ket/xyl improved mortality 24 h after MCAO (10 vs. 50 %, p = 0.037) and predominantly led to striatal infarcts (78 vs. 18 %, p = 0.009) without involvement of the neocortex and medial caudoputamen. Independent of anesthesia type, cortical infarcts could be predicted with a sensitivity of 67 % and a specificity of 100 % if CBF did not exceed 35 % of the baseline value during ischemia. In all other cases, cortical infarcts developed if the reperfusion values remained below 50 %. Hyperemia during reperfusion significantly increased infarct and edema volumes. The cause of frequent striatal infarcts after isoflurane anesthesia might be attributed to an improved CBF during ischemia (46 ± 15 % vs. 35 ± 19 %, p = 0.04). S-100β release, edema volume and upregulation of IL-6 and IL-1β expression were impeded by isoflurane. Thus, anesthetic management as well as the grade of ischemia and reperfusion after transient MCAO demonstrated important effects on neurological injury.

Surgically induced fire is a life-threatening hazard; this topic has received little attention, although only 3 factors, the so-called fire triad, are needed for surgical fires to occur: an oxidizer, fuel and an ignition source. This systematic review aims to determine the impact of each component and to delegate every staff member an area of responsibility, thus ensuring patient health through prevention or protection. The trial was registered in Prospero CRD42018082656. A database search of eligible, preferably evidence-based studies was conducted. The Robins-I tool for assessing the risk of bias revealed a moderate risk of bias. Due to insufficient data, the main findings of these studies could not be summarized through a quantitative synthesis; therefore, a qualitative synthesis is outlined. The results are summarized according to the roles of the fire triad and discussed. (1) Role of the oxidizer: oxygen is the key component of the triad. Safe oxygen delivery is important. An oxygen-enriched environment (ORE) is caused by draping and is preferably prevented by suctioning. Fuel characteristics are affected by varying oxygen concentrations. (2) Role of the ignition source: electrocauterization is the most common ignition source, followed by lasers. Less common ignition sources include fiberoptic cables and preparative solutions, petrol or acetone. (3) Role of the fuel: surgical drapes are one of the most common fuels for surgical fires followed by the patient's hair and skin. Skin preparation solutions are among the less common fuels. Many fire-resistant materials have been tested that do not remain fire resistant in ORE. It was concluded that the main problem is defining the real extent of this hazard. Exact numbers and exact condition protocols are needed; therefore, standardized registration of every fire and future studies with much evidence are needed. Immediate prevention consists of close attention to patient safety to prevent surgical fires from happening.