A new understanding of the complex ways in which general anaesthetics act on the brain could eventually lead to improved drugs for surgery. | via Journal of Anaesthesia Practice
Although general anaesthesia is one of the most common medical procedures worldwide, it remains unclear how general anaesthesia works. In this research article, Professor Bruno van Swinderen, says his team had overturned previous understanding of what general anaesthetics do to the brain, finding the drugs did much more than induce sleep.
Propofol is the most commonly used general anesthetic in humans. Our understanding of its mechanism of action has focused on its capacity to potentiate inhibitory systems in the brain. However, it is unknown whether other neural mechanisms are involved in general anesthesia.
Here, we demonstrate that the synaptic release machinery is also a target. Using single-particle tracking photoactivation localization microscopy, we show that clinically relevant concentrations of propofol and etomidate restrict syntaxin1A mobility on the plasma membrane, whereas non-anesthetic analogs produce the opposite effect and increase syntaxin1A mobility.
Removing the interaction with the t-SNARE partner SNAP-25 abolishes propofol-induced syntaxin1A confinement, indicating that syntaxin1A and SNAP-25 together form an emergent drug target. Impaired syntaxin1A mobility and exocytosis under propofol are both rescued by co-expressing a truncated syntaxin1A construct that interacts with SNAP-25.
Our results suggest that propofol interferes with a step in SNARE complex formation, resulting in non-functional syntaxin1A nanoclusters.
The head of the CU School of Medicine Department of Anesthesiology in Colorado, has written a review of scientific studies on the potentially adverse effects of exposing developing brains to general anaesthesia | Anesthesiology
Recently, the U.S. Food and Drug Administration issued an official warning to all practicing physicians regarding potentially detrimental behavioral and cognitive sequelae of an early exposure to general anesthesia during in utero and in early postnatal life.
The U.S. Food and Drug Administration concern is focused on children younger than three years of age who are exposed to clinically used general anesthetics and sedatives for three hours or longer.
Although human evidence is limited and controversial, a large body of scientific evidence gathered from several mammalian species demonstrates that there is a potential foundation for concern. Considering this new development in public awareness, this review focuses on nonhuman primates because their brain development is the closest to humans in terms of not only timing and duration, but in terms of complexity as well.
Children with cancer could be spared dozens of doses of general anaesthesia by projecting a video directly on to the inside of a radiotherapy machine during treatment | OnMedica
The new research was presented this week at the ESTRO 36 conference (European Society for Radiotherapy & Oncology), taking place in Vienna, Austria.
Catia Aguas, a radiation therapist and dosimetrist at the Cliniques Universitaires Saint Luc, Brussels, Belgium, told the conference that using video instead of general anaesthesia is less traumatic for children and their families, as well as making each treatment quicker and more cost effective.
The study included 12 children aged between one and a half and six years old who were treated with radiotherapy using a Tomotherapy® treatment unit at the university hospital. Six were treated before a video projector was installed in 2014 and six were treated after.
Before the video was available, general anaesthesia was needed for 83% of children’s treatments. Once the projector was installed, anaesthesia was only needed in 33% of treatments.
Rajagopalan S, et al. (2017) International Journal of Obstetric Anesthesia. 29(3) pp. 64-9
Introduction: With the increasing popularity of neuraxial anaesthesia, there has been a decline in the use of general anaesthesia for Caesarean delivery. These authors sought to examine the incidence, outcome and characteristics associated with a failed airway in patients undergoing Caesarean delivery under general anaesthesia.
Conclusions: The authors conclude that advances in adjunct airway equipment, availability of an experienced anaesthetist and simulation-based teaching of failed airway management in obstetrics may have contributed to their improved maternal outcomes in patients undergoing Caesarean delivery under general anaesthesia.
Meng, T. et al. (2017) Anaesthesia. 72(3) pp. 391-401
Introduction: The authors systematically reviewed the comparative evidence for the use of spinal anaesthesia versus general anaesthesia for lumbar spinal surgery.
Results: Eight studies with a total of 625 patients were included. These were considered to be at high risk of bias. Compared with general anaesthesia, the risk ratio (95% confidence interval [CI]) with spinal anaesthesia for intraoperative hypertension was 0.31 (0.15 to 0.64), I2 = 0% (p=0.002); for intraoperative tachycardia 0.51 (0.30 to 0.84), I2 = 0% (p=0.009); for analgesic requirement in the post-anaesthesia care unit 0.32 (0.24 to 0.43), I2 = 0% (p<0.0001); and for nausea/vomiting within 24 hours postoperatively 0.29 (0.18 to 0.46), I2 = 12% (p<0.00001). The standardised mean difference (95% CI) for hospital stay was -1.15 (–1.98 to –0.31), I2 = 89% (p=0.007). There was no evidence of a difference in intraoperative hypotension and bradycardia, blood loss, surgical time and analgesic requirement within 24 hours postoperatively or nausea/vomiting in the post-anaesthesia care unit.
Conclusions: The authors conclude that spinal anaesthesia appears to offer advantages over general anaesthesia for lumbar spine surgery.
Juang, J. et al. Anesthesia & Analgesia. Published online: January 16 2017
Neuraxial anesthesia use in cesarean deliveries (CDs) has been rising since the 1980s, whereas general anesthesia (GA) use has been declining.
In this brief report we analyzed recent obstetric anesthesia practice patterns using National Anesthesiology Clinical Outcomes Registry data. Approximately 218,285 CD cases were identified between 2010 and 2015. GA was used in 5.8% of all CDs and 14.6% of emergent CDs.
Higher rates of GA use were observed in CDs performed in university hospitals, after hours and on weekends, and on patients who were American Society of Anesthesiologists class III or higher and 18 years of age or younger.
Background: This propensity score–matched cohort study evaluates the effect of anesthetic technique on a 30-day mortality after total hip or knee arthroplasty.
Methods: All patients who had hip or knee arthroplasty between January 1, 2003, and December 31, 2014, were evaluated. The principal exposure was spinal versus general anesthesia. The primary outcome was 30-day mortality. Secondary outcomes were (1) perioperative myocardial infarction; (2) a composite of major adverse cardiac events that includes cardiac arrest, myocardial infarction, or newly diagnosed arrhythmia; (3) pulmonary embolism; (4) major blood loss; (5) hospital length of stay; and (6) operating room procedure time. A propensity score–matched-pair analysis was performed using a nonparsimonious logistic regression model of regional anesthetic use.
Results: We identified 10,868 patients, of whom 8,553 had spinal anesthesia and 2,315 had general anesthesia. Ninety-two percent (n = 2,135) of the patients who had general anesthesia were matched to similar patients who did not have general anesthesia. In the matched cohort, the 30-day mortality rate was 0.19% (n = 4) in the spinal anesthesia group and 0.8% (n = 17) in the general anesthesia group (risk ratio, 0.42; 95% CI, 0.21 to 0.83; P = 0.0045). Spinal anesthesia was also associated with a shorter hospital length of stay (5.7 vs. 6.6 days; P < 0.001).
Conclusions: The results of this observational, propensity score–matched cohort study suggest a strong association between spinal anesthesia and lower 30-day mortality, as well as a shorter hospital length of stay, after elective joint replacement surgery.