Incidence and clinical impact of aspiration during cesarean delivery: A multi-center retrospective study

BACKGROUND

The risk of aspiration during general anesthesia for cesarean delivery has long been thought to be increased due to factors such as increased intra-abdominal pressures and delayed gastric emptying in pregnant patients. However, recent studies have reported normal gastric emptying in pregnant patients, suggesting that the risk of aspiration may not be as high as previously believed.

METHODS

We conducted a retrospective study of 48,609 cesarean deliveries, of which 22,690 (46.7%) were performed under general anesthesia at two large tertiary medical centers in Israel. The study aimed to examine the incidence of potentially severe aspiration during cesarean delivery, both under general and neuraxial anesthesia.

RESULTS

Among the patients included in the study, three were admitted to the intensive care unit due to suspected pulmonary aspiration. Two of these cases occurred during induction of general anesthesia for emergency cesarean delivery associated with difficult intubation and one under deep sedation during spinal anesthesia. The incidence of aspiration during cesarean delivery during general anesthesia in our study was 1 in 11,345 patients, and the incidence of aspiration during neuraxial anesthesia was 1 in 25,929 patients. No deaths due to aspiration were reported during the study period.

CONCLUSIONS

Our findings provide another contemporary analysis of aspiration rates in obstetric patients, highlighting increased risks during the management of difficult airways during general anesthesia and deep sedation associated with neuraxial anesthesia.

The effect of pyruvate on the development and progression of post-stroke depression: A new therapeutic approach

Post-stroke depression (PSD) is a common and serious complication following stroke. Both stroke and depression have independently been associated with pathologically elevated glutamate levels in the brain's extra-cerebral fluid (ECF). Here we evaluate an alternative therapeutic approach to PSD with pyruvate. Rats were randomly assigned into one of 3 groups: Middle Cerebral Artery Occlusion (MCAO) plus pyruvate treatment, MCAO plus placebo treatment, and sham operated rats. Post-MCAO depressive and anxiety-like behavior was assessed, along with neurological status, brain infarct zone, brain edema, blood brain barrier (BBB) breakdown, cerebrospinal fluid and blood glutamate levels. Anxiety-like behavior and levels of blood alanine and α-ketoglutarate were measured in naïve rats treated with pyruvate, as a control. Post-stroke neurological deficit with concurrent elevation in glutamate levels were demonstrated, with peak glutamate levels 24 h after MCAO. Treatment with pyruvate led to reduced glutamate levels 24 h after MCAO and improved neurologic recovery. Pyruvate treatment reduced lesion volume, brain edema and the extent of BBB permeability 24 h post-MCAO. Naïve rats treated with pyruvate showed increased levels of α-ketoglutarate. Rats demonstrated post-stroke depressive behavior that was improved by the administration of pyruvate. There was less anxiety-like behavior in post-stroke rats treated with placebo in comparison to the post-stroke rats treated with pyruvate or sham operated rats. Glutamate scavenging with pyruvate appears to be an effective as a method in providing neuroprotection following stroke and as a therapeutic option for the treatment of PSD by reducing the consequent elevations in CNS glutamate levels.

Neutrophil functions in morbidly obese subjects

The present study aimed to determine different peripheral blood neutrophil functions in 18 morbidly obese subjects with body mass index (BMI) ranging between 35 and 69 kg/m(2) in parallel with age- and gender-matched lean controls. Peripheral blood neutrophil functions of obese subjects and matched lean controls were determined. Neutrophils of obese subjects showed significant elevation of the release of basal superoxides (P < 0.0001), formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated superoxides (P < 0.0001) and opsonized zymosan (OZ)-stimulated superoxides (P < 0.045) compared with lean controls. Interestingly, there were no differences in phorbol myristate acetate (PMA)-stimulated superoxide production by neutrophils of the obese subjects and controls. There was also a significant elevation of chemotactic (P < 0.0003) and random (P < 0.0001) migration of neutrophils from obese subjects compared with lean controls. Phagocytosis, CD11b surface expression and adherence of neutrophils from obese subjects were not significantly different from those of the lean controls. The elevated superoxide production and chemotactic activity, together with the normal phagocytosis and adherence, suggest that neutrophils from obese subjects are primed and have the capability to combat infections. However, neutrophils in the priming state may participate in the pathogenesis of obesity-related diseases.

Extracorporeal methods of blood glutamate scavenging: a novel therapeutic modality

Pathologically elevated glutamate concentrations in the brain's extracellular fluid are associated with several acute and chronic brain insults. Studies have demonstrated that by decreasing the concentration of glutamate in the blood, thereby increasing the concentration gradient between the brain and the blood, the rate of brain-to-blood glutamate efflux can be increased. Blood glutamate scavengers, pyruvate and oxaloacetate have shown great promise in providing neuroprotection in many animal models of acute brain insults. However, glutamate scavengers' potential systemic toxicity, side effects and pharmacokinetic properties may limit their use in clinical practice. In contrast, extracorporeal methods of blood glutamate reduction, in which glutamate is filtered from the blood and eliminated, may be an advantageous adjunct in treating acute brain insults. Here, we review the current evidence for the glutamate-lowering effects of hemodialysis, peritoneal dialysis and hemofiltration. The evidence reviewed here highlights the need for clinical trials.

The neuro-behavioral profile in rats after subarachnoid hemorrhage

Despite significant advancements in the understanding of the pathophysiological mechanisms of subarachnoid hemorrhage (SAH), little is known about the emotional consequences. The primary goal of this study was to describe the locomotor and behavioral patterns in rats following both a single-injection and double-injection model of SAH. In 48 rats, SAH was induced by injecting 0.3 ml of autologous arterial blood into the cisterna magnum (single-hemorrhagic model). In 24 of these rats, post-SAH vasospasm was induced by a repeated injection of blood into the cisterna magnum 24h later (double-hemorrhagic model). In 24 additional rats, 0.3 ml of saline was injected into the cisterna magnum (sham group). Neurological performance was assessed at 24, 48 h, 1, 2 and 3 weeks after SAH. Four behavioral tests were performed for 3 weeks after SAH for the duration of 6 consequent days, in the following order: open field test, sucrose preference test, elevated plus maze test and forced swimming test. Following both, a single and double-hemorrhagic models of SAH, rats were found to have significant behavioral abnormalities on the open field test, sucrose preference test, elevated plus maze test, and forced swimming test. A more prominent disability was found in rats that underwent the double-hemorrhagic model of SAH than rats that underwent the single-hemorrhagic model. Both a single and double injection model of rats SAH are associated with significant behavioral disturbances including locomotor abnormalities, depressive behavior and increased anxiety, even as early as 3 weeks after SAH.

Relationship between glutamate, GOT and GPT levels in maternal and fetal blood: a potential mechanism for fetal neuroprotection

BACKGROUND

Excess glutamate in the brain is thought to be implicated in the pathophysiology of fetal anoxic brain injury, yet little is known about the mechanisms by which glutamate is regulated in the fetal brain. This study examines whether there are differences between maternal and fetal glutamate concentrations, and whether a correlation between them exists.

METHODS

10 ml of venous blood was extracted from 87 full-term (>37 weeks gestation) pregnant women in active labor. Immediately after delivery of the neonate, 10 ml of blood from the umbilical artery and vein was extracted. Samples were analyzed for levels of glutamate, glutamate-oxaloacetate transaminase (GOT), and glutamate pyruvate transaminase (GPT).

RESULTS

Fetal blood glutamate concentrations in both the umbilical artery and vein were found to be significantly higher than maternal blood (p<0.001). Similarly, fetal serum GOT levels in the umbilical artery and vein were found to be significantly higher than maternal GOT levels (p<0.001). The difference in GPT levels between maternal and fetal serum was not statistically significant. There was no difference in fetal glutamate, GOT or GPT between the umbilical artery and vein. There was an association observed between glutamate levels in maternal blood and glutamate levels in both venous (R=0.32, p<0.01) and arterial (R=0.33, p<0.05) fetal blood.

CONCLUSIONS

This study demonstrated that higher baseline concentrations of blood glutamate are present in fetal blood compared with maternal blood, and this was associated with elevated GOT, but not GPT levels. An association was observed between maternal and fetal blood glutamate levels.

The effect of blood glutamate scavengers oxaloacetate and pyruvate on neurological outcome in a rat model of subarachnoid hemorrhage

Blood glutamate scavengers have been shown to effectively reduce blood glutamate concentrations and improve neurological outcome after traumatic brain injury and stroke in rats. This study investigates the efficacy of blood glutamate scavengers oxaloacetate and pyruvate in the treatment of subarachnoid hemorrhage (SAH) in rats. Isotonic saline, 250 mg/kg oxaloacetate, or 125 mg/kg pyruvate was injected intravenously in 60 rats, 60 minutes after induction of SAH at a rate of 0.1 ml/100 g/min for 30 minutes. There were 20 additional rats that were used as a sham-operated group. Blood samples were collected at baseline and 90 minutes after SAH. Neurological performance was assessed at 24 h after SAH. In half of the rats, glutamate concentrations in the cerebrospinal fluid were measured 24 h after SAH. For the remaining half, the blood brain barrier permeability in the frontal and parieto-occipital lobes was measured 48 h after SAH. Blood glutamate levels were reduced in rats treated with oxaloacetate or pyruvate at 90 minutes after SAH (p < 0.001). Cerebrospinal fluid glutamate was reduced in rats treated with pyruvate (p < 0.05). Neurological performance was significantly improved in rats treated with oxaloacetate (p < 0.05) or pyruvate (p < 0.01). The breakdown of the blood brain barrier was reduced in the frontal lobe in rats treated with pyruvate (p < 0.05) and in the parieto-occipital lobes in rats treated with either pyruvate (p < 0.01) or oxaloacetate (p < 0.01). This study demonstrates the effectiveness of blood glutamate scavengers oxaloacetate and pyruvate as a therapeutic neuroprotective strategy in a rat model of SAH.