Concept: General anaesthesia
General anesthetics are used during medical and surgical procedures to reversibly induce a state of total unconsciousness in patients. Here, we investigate, from a dynamic network perspective, how the cortical and cardiovascular systems behave during anesthesia by applying nonparametric spectral techniques to cortical electroencephalography, electrocardiogram and respiratory signals recorded from anesthetized rats under two drugs, ketamine-xylazine (KX) and pentobarbital (PB). We find that the patterns of low-frequency cortico-cardio-respiratory network interactions may undergo significant changes in network activity strengths and in number of network links at different depths of anesthesia dependent upon anesthetics used.
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 Effects of Different Oxygen Concentrations on Recruitment Maneuver During General Anesthesia for Laparoscopic Surgery
- Surgical laparoscopy, endoscopy & percutaneous techniques
- Published over 4 years ago
Recruitment maneuvers (RMs), which aim to ventilate the collaborated alveolus by temporarily increasing the transpulmonary pressure, have positive effects in relation to respiration, mainly oxygenation. Although many studies have defined the pressure values used during RM and the application period, our knowledge of the effects of different oxygen concentrations is limited. In this study, we aimed to determine the effects of different oxygen concentrations during RM on the arterial oxygenation and respiration mechanics in laparoscopic cases.
BACKGROUND: Entrapped anorectal foreign bodies are being encountered more frequently in clinical practice. Although entrapped foreign bodies are most often related to sexual behavior, they can also result from ingestion or sexual assault. METHODS: Between 1999 and 2009, 15 patients with foreign bodies in the rectum were diagnosed and treated, at Izmir Training and Research Hospital, in Izmir. Information regarding the foreign body, clinical presentation, treatment strategies, and outcomes were documented. We retrospectively reviewed the medical records of these unusual patients. RESULTS: All patients were males, and their mean age was 48 years (range, 33¿68 years). The objects in the rectum of these 15 patients were an impulse body spray can (4 patients), a bottle (4 patients), a dildo (2 patient), an eggplant (1 patient), a brush (1 patient), a tea glass (1 patient), a ball point pen (1 patient) and a wishbone (1 patient, after oral ingestion). Twelve objects were removed transanally by anal dilatation under general anesthesia. Three patients required laparotomy. Routine rectosigmoidoscopic examination was performed after removal. One patient had perforation of the rectosigmoid and 4 had lacerations of the mucosa. None of the patients died. CONCLUSIONS: Foreign bodies in the rectum should be managed in a well-organized manner. The diagnosis is confirmed by plain abdominal radiographs and rectal examination. Manual extraction without anaesthesia is only possible for very low-lying objects. Patients with high- lying foreign bodies generally require general anaesthesia to achieve complete relaxation of the anal sphincters to facilitate extraction. Open surgery should be reserved only for patients with perforation, peritonitis, or impaction of the foreign body.
Cuffed tracheal tubes are increasingly used in paediatric anaesthetic practice. This study compared tidal volume and leakage around cuffed and uncuffed tracheal tubes in children who required standardised mechanical ventilation of their lungs in the operating theatre. Children (0-16 years) undergoing elective surgery requiring tracheal intubation were randomly assigned to receive either a cuffed or an uncuffed tracheal tube. Assessments were made at five different time-points: during volume-controlled ventilation 6 ml.kg(-1) , PEEP 5 cmH2 O and during pressure-controlled ventilation 10 cmH2 O / PEEP 5 cmH2 O. The pressure-controlled ventilation measurement time-points were: just before a standardised recruitment manoeuvre; just after recruitment manoeuvre; 10 min; and 30 min after the recruitment manoeuvre. Problems and complications were recorded. During volume-controlled ventilation, leakage was significantly less with cuffed tracheal tubes than with uncuffed tracheal tubes; in ml.kg(-1) , median (IQR [range]) 0.20 (0.13-0.39 [0.04-0.60]) vs. 0.82 (0.58-1.38 [0.24-4.85]), respectively, p < 0.001. With pressure-controlled ventilation, leakage was less with cuffed tracheal tubes and stayed unchanged over a 30-min period, whereas with uncuffed tracheal tubes, leakage was higher and increased further over the 30-min period. Tidal volumes were higher in the cuffed group and increased over time, but in the uncuffed group were lower and decreased over time. Both groups showed an increase in tidal volumes following recruitment manoeuvres. There were more short-term complications with uncuffed tracheal tubes, but no major complications were recorded in either group at long-term follow-up. With standardised ventilator settings, cuffed tracheal tubes produced better ventilation characteristics compared with uncuffed tracheal tubes during general anaesthesia for routine elective surgery.
- Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
- Published over 4 years ago
Anesthesia in infancy impairs performance in recognition memory tasks in mammalian animals, but it is unknown if this occurs in humans. Successful recognition can be based on stimulus familiarity or recollection of event details. Several brain structures involved in recollection are affected by anesthesia-induced neurodegeneration in animals. Therefore, we hypothesized that anesthesia in infancy impairs recollection later in life in humans and rats. Twenty eight children ages 6-11 who had undergone a procedure requiring general anesthesia before age 1 were compared to twenty eight age- and gender-matched children who had not undergone anesthesia. Recollection and familiarity were assessed in an object recognition memory test using receiver operator characteristic analysis. In addition, IQ and Child Behavior Checklist scores were assessed. In parallel, thirty three 7-day old rats were randomized to receive anesthesia or sham anesthesia. Over ten months, recollection and familiarity were assessed using an odor recognition test. We found that anesthetized children had significantly lower recollection scores and were impaired at recollecting associative information compared to controls. Familiarity, IQ, and Child Behavior Checklist scores were not different between groups. In rats, anesthetized subjects had significantly lower recollection scores than controls while familiarity was unaffected. Rats that had undergone tissue injury during anesthesia had similar recollection indices as rats that had been anesthetized without tissue injury. These findings suggest that general anesthesia in infancy impairs recollection later in life in humans and rats. In rats, this effect is independent of underlying disease or tissue injury.Neuropsychopharmacology accepted article preview online, 9 June 2014; doi:10.1038/npp.2014.134.
The aim of this study was to develop an audit tool to identify prospectively all peri-operative adverse events during airway management in a cost-effective and reproducible way. All patients at VU University Medical Center who required general anaesthesia for elective and emergency surgical procedures were included during a period of 8 weeks. Daily questionnaires and interviews were taken from anaesthesia trainees and anaesthetic department staff members. A total of 2803 patients underwent general anaesthesia, 1384 men and 1419 women, including 2232 elective patients and 571 emergency procedures, 697 paediatric and 2106 adult surgical procedures. A total of 168 airway-related events were reported. The incidence of severe airway management-related events was 24/2803 (0.86%). There were 12 (0.42%) unanticipated ICU admissions, two patients (0.07%) required a surgical airway. There was one (0.04%) death, one cannot intubate cannot oxygenate (0.04%), one aspiration (0.04%) and eight (0.29%) severe desaturations < Sp O2 50%. We suggest that our method to determine and investigate airway management-related adverse events could be adopted by other hospitals.
Unrecognized malposition of the endotracheal tube (ETT) can lead to severe complications in patients under general anesthesia. The focus of this double-blinded randomized study was to assess the accuracy of point-of-care ultrasound in verifying the correct position of the ETT and to compare it with the accuracy of auscultation.
In trauma patients intubated in a physician-led pre-hospital trauma service we prospectively examined the rate of misplaced tracheal tubes, the presence and nature of gross airway contamination, and the value of ‘quick look’ airway assessment to identify patients with subsequent difficult laryngoscopy.
Forced air warming (FAW) during general anaesthesia is a safe and effective intervention used to reduce hypothermia. The objective of this study was to determine if FAW reduces hypothermia when used for procedures performed with sedation in the cardiac catheterisation laboratory.