End-tidal control vs. manually controlled minimal-flow anesthesia: a prospective comparative trial.

BACKGROUND: To ensure safe general anesthesia, manually controlled anesthesia requires constant monitoring and numerous manual adjustments of the gas dosage, especially for low- and minimal-flow anesthesia. Oxygen flow-rate and administration of volatile anesthetics can also be controlled automatically by anesthesia machines using the end-tidal control technique, which ensures constant end-tidal concentrations of oxygen and anesthetic gas via feedback and continuous adjustment mechanisms. We investigated the hypothesis that end-tidal control is superior to manually controlled minimal-flow anesthesia (0.5 l/min). METHODS: In this prospective trial, we included 64 patients undergoing elective surgery under general anesthesia. We analyzed the precision of maintenance of the sevoflurane concentration (1.2-1.4%) and expiratory oxygen (35-40%) and the number of necessary adjustments. RESULTS: Target-concentrations of sevoflurane and oxygen were maintained at more stable levels with the use of end-tidal control (during the first 15 min 28% vs. 51% and from 15 to 60 min 1% vs. 19% deviation from sevoflurane target, P < 0.0001; 45% vs. 86% and 5% vs. 15% deviation from O2 target, P < 0.01, respectively), while manual controlled minimal-flow anesthesia required more interventions to maintain the defined target ranges of sevoflurane (8, IQR 6-12) and end-tidal oxygen (5, IQR 3-6). The target-concentrations were reached earlier with the use of end-tidal compared with manual controlled minimal-flow anesthesia but required slightly greater use of anesthetic agents (6.9 vs. 6.0 ml/h). CONCLUSIONS: End-tidal control is a superior technique for setting and maintaining oxygen and anesthetic gas concentrations in a stable and rapid manner compared with manual control. Consequently, end-tidal control can effectively support the anesthetist.

Anthocyanins in vegetative tissues: a proposed unified function in photoprotection.

The function of anthocyanins in green, vegetative tissues has always been a contentious issue. Here we evaluate their proposed photoprotective function since recent findings have shown that anthocyanins reduce photoinhibition and photobleaching of chlorophyll under light stress conditions. Anthocyanins generally accumulate in peripheral tissues exposed to high irradiance, although there are some exceptions (e.g. accumulation in abaxial leaf tissues and in obligatory shade plants) and accumulation is usually transient. Anthocyanin accumulation requires light and generally coincides with periods of high excitation pressure and increased potential for photo-oxidative damage due to an imbalance between light capture, CO2 assimilation and carbohydrate utilization (e.g. greening of developing tissues, senescence and adverse environmental conditions). Light attenuation by anthocyanin may help to re-establish this balance and so reduce the risk of photo-oxidative damage. Although it has been suggested that anthocyanins may act as antioxidants, the association between anthocyanins and oxidative stress appears to relate to the ability of anthocyanins to reduce excitation pressure and, hence, the potential for oxidative damage. The various aspects of anthocyanin induction and pigmentation presented here are compatible with, and support, the proposed general role of anthocyanins as photoprotective light screens in vegetative tissues.

A histological study of the promotive effect of diethylstilbestrol on diethylnitrosamine initiated carcinogenesis of liver in rat.

A single dose (80 mg/kg) of diethylnitrosamine (DEN) was given orally to castrated female Wistar rats. One week after that one half of the animals were treated with diethylstilbestrol (DES) 3 mg/kg/once a week subcutaneously. The other half of the animals received no any hormone or hormone derivatives. The change of the liver cells in animals treated with DEN alone failed to progress beyond the stage of hepatocellular alterations in foci or neoplastic nodules within 8 months, while most of those animals which received DES treatment after DEN initiation developed hepatocellular carcinomas after 6 months. This result denotes that the DES exerts a definite promotive effect on DEN initiated liver cell carcinogenesis.

Growth, phenology and reproduction of an arid-environment winter ephemeral Dimorphotheca pluvialis in response to combined increases in CO2 and UV-B radiation.

The winter ephemeral Dimorphotheca pluvialis was grown in open-top chambers in ambient or elevated CO2 (350 or 650 micromol mol(-1)), combined with ambient (2.39 to 7.59 kJ m(-2) d(-1)) or increased (4.94 to 11.13 kJ m(-2) d(-1)) UV-B radiation. Net CO2 assimilation rate and leaf water use efficiency increased in elevated CO2, but increased UV-B did not affect gas exchange. Leaf biomass was greater under increased UV-B, but vegetative biomass was unaffected in elevated CO2. Initiation of reproduction was delayed, and proportional investment in reproductive biomass at harvest was reduced in elevated CO2. Increased UV-B stimulated reproduction, particularly in ambient CO2, but also in elevated CO2 at a later stage. Changes in reproductive phenology and prolonged development in elevated CO2 during the stressful late season could indirectly be detrimental to reproductive success of D. pluvialis, but stimulation of reproduction by enhanced UV-B may to some extent mitigate this.

Acute liver failure due to acute fatty liver of pregnancy.

Acute fatty liver of pregnancy (AFLP) is a rare but serious liver disease and typically occurs during the third trimester. It carries the risk for significant perinatal and maternal mortality. Therefore an early diagnosis and delivery, followed by close monitoring and optimized management of the impaired liver function with all associated problems are necessary to prevent maternal and foetal death. This case report focuses on the management of acute liver failure due to AFLP in a 31 year old women treated in our intensive care unit (ICU) after an emergency C-section.

Association of non-reassuring fetal heart rate and fetal acidosis with placental histopathology.

OBJECTIVE: To investigate the association between different placental lesions and non-reassuring fetal heart rate (NRFHR) pattern and fetal acidosis in labor. STUDY DESIGN: Placentas from 213 women who underwent cesarean section because of NRFHR with or without fetal acidosis (pH < 7.2) were classified by histopathologic findings: consistent with maternal circulation abnormalities i.e., namely, marginal or retroplacental hemorrhage (M0), maternal underperfusion, vascular (M1) or villous changes (M2), and those consistent with fetal thrombo-occlusive disease due to vascular (F1) or villous (F2) changes. Lesions were also analyzed by maternal (MIR) or fetal (FIR) origin of inflammatory responses. RESULTS: Cord blood pH was normal in 169 neonates (7.29 ± 0.04; control group) and <7.2 in 44 (7.10 ± 0.07; study group). The study group had higher rates of histologic chorioamnionitis; MIR was detected in 34.1% compared to17.8% of controls (p = 0.018), and FIR, in 18.2% compared to 6.5% (p = 0.016). Neonates in the study group had lower Apgar scores and longer hospitalization. CONCLUSIONS: Placental MIR and FIR are associated with cord blood acidosis in neonates delivered by cesarean section for NRFHR tracings in labor.

Post-void residual volume in labor: a prospective study comparing parturients with and without epidural analgesia.

BACKGROUND: This prospective, non-randomized study compared post-void residual volume in laboring and postpartum women with or without epidural analgesia. METHODS: The study was conducted over 1 year with institutional review board approval. Parturients were recruited in early labor and self-selected to either the study (with epidural) or control (without epidural) group. Post-void residual volume was compared between groups, using transabdominal ultrasound during labor, and on postpartum day 1 and 2. Main outcome measure was intrapartum residual bladder volume. RESULTS: Thirty patients were recruited to each group. During labor, residual bladder volume was significantly larger in the epidural group compared with the non-epidural group [median (range)] 240 (12-640), ml vs. 45 (13-250) ml, respectively, P < 0.001], but was similar on postpartum day 1 and 2. Twenty-five (83%) women with epidural analgesia required bladder catheterization during labor vs. one (3.3%) without (P < 0.0001). CONCLUSION: The greater post-void residual volume and increased inability to void in parturients with epidurals suggests that epidural analgesia plays a role in intrapartum urinary retention.