General anaesthesia is usually associated with unconsciousness. 'Awareness' is when patients have postoperative recall of events or experiences during surgery. 'Wakefulness' is when patients become ...conscious during surgery, but have no postoperative recollection of the period of consciousness.
To evaluate the efficacy of two types of anaesthetic interventions in reducing clinically significant awareness:- anaesthetic drug regimens; and- intraoperative anaesthetic depth monitors.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL, ISSUE 4 2016); PubMed from 1950 to April 2016; MEDLINE from 1950 to April 2016; and Embase from 1980 to April 2016. We contacted experts to identify additional studies. We performed a handsearch of the citations in the review. We did not search trial registries.
We included randomized controlled trials (RCTs) of either anaesthetic regimens or anaesthetic depth monitors. We excluded volunteer studies, studies of patients prior to skin incision, intensive care unit studies, and studies that only randomized different word presentations for memory tests (not anaesthetic interventions).Anaesthetic drug regimens included studies of induction or maintenance, or both. Anaesthetic depth monitors included the Bispectral Index monitor, M-Entropy, Narcotrend monitor, cerebral function monitor, cerebral state monitor, patient state index, and lower oesophageal contractility monitor. The use of anaesthetic depth monitors allows the titration of anaesthetic drugs to maintain unconsciousness.
At least two authors independently scanned abstracts, extracted data from the studies, and evaluated studies for risk of bias. We made attempts to contact all authors for additional clarification. We performed meta-analysis statistics in packages of the R language.
We included 160 studies with 54,109 enrolled participants; 53,713 participants started the studies and 50,034 completed the studies or data analysis (or both). We could not use 115 RCTs in meta-analytic comparisons because they had zero awareness events. We did not merge 27 of the remaining 45 studies because they had excessive clinical and methodological heterogeneity. We pooled the remaining 18 eligible RCTs in meta-analysis. There are 10 studies awaiting classification which we will process when we update the review.The meta-analyses included 18 trials with 36,034 participants. In the analysis of anaesthetic depth monitoring (either Bispectral Index or M-entropy) versus standard clinical and electronic monitoring, there were nine trials with 34,744 participants. The overall event rate was 0.5%. The effect favoured neither anaesthetic depth monitoring nor standard clinical and electronic monitoring, with little precision in the odds ratio (OR) estimate (OR 0.98, 95% confidence interval (CI) 0.59 to 1.62).In a five-study subset of Bispectral Index monitoring versus standard clinical and electronic monitoring, with 34,181 participants, 503 participants gave awareness reports to a blinded, expert panel who adjudicated or judged the outcome for each patient after reviewing the questionnaires: no awareness, possible awareness, or definite awareness. Experts judged 351 patient awareness reports to have no awareness, 87 to have possible awareness, and 65 to have definite awareness. The effect size favoured neither Bispectral Index monitoring nor standard clinical and electronic monitoring, with little precision in the OR estimate for the combination of definite and possible awareness (OR 0.96, 95% CI 0.35 to 2.65). The effect size favoured Bispectral Index monitoring for definite awareness, but with little precision in the OR estimate (OR 0.60, 95% CI 0.13 to 2.75).We performed three smaller meta-analyses of anaesthetic drugs. There were nine studies with 1290 participants. Wakefulness was reduced by ketamine and etomidate compared to thiopental. Wakefulness was more frequent than awareness. Benzodiazepines reduces awareness compared to thiopental, ketamine, and placebo., Also, higher doses of inhaled anaesthetics versus lower doses reduced the risk of awareness.We graded the quality of the evidence as low or very low in the 'Summary of findings' tables for the five comparisons.Most of the secondary outcomes in this review were not reported in the included RCTs.
Anaesthetic depth monitors may have similar effects to standard clinical and electrical monitoring on the risk of awareness during surgery. In older studies comparing anaesthetics in a smaller portion of the patient sample, wakefulness occurred more frequently than awareness. Use of etomidate and ketamine lowered the risk of wakefulness compared to thiopental. Benzodiazepines compared to thiopental and ketamine, or higher doses of inhaled anaesthetics versus lower doses, reduced the risk of awareness.
The use of breathing filters (BFs) has been recommended to protect the anesthesia apparatus in proven or suspected cases of tuberculosis. Some investigators have also suggested the use of BF to ...alleviate the need to change anesthesia breathing circuits after each case. This study evaluated the filtration efficacy of three different BFs to prevent mycobacterial contamination of breathing circuits in a model that uses a test animal.
Ten Pall BB25A (pleated hydrophobic) (Pall Canada Ltd., Mississauga, Ontario, Canada), six DAR Barrierbac S (felted electrostatic; Mallinckrodt DAR, Mirandola, Italy), and six Baxter Airlife (felted electrostatic; Baxter Canada, Mississauga, Ontario, Canada) BFs were studied. For each BF tested, 20 ml of a high concentration suspension of Mycobacterium chelonae (range, 2.0 x 10 to 9.0 x 10 colony-forming units/ml) was nebulized during 2 h at the proximal end of the endotracheal tube of anesthetized pigs. At the end of the nebulization period, the BFs were sampled for culture. The titer reduction value (number of microorganisms challenging the BF divided by the number of microorganisms recovered downstream of the BF) and the removal efficiency (difference between the number of microorganisms challenging the BF and the number of microorganisms recovered downstream of the BF, divided by the number of microorganisms challenging the BF) were calculated.
The median titer reduction values were 5.6 x 10, 6.0 x 10, and 8.0 x 10 (P < 0.0005), and the median removal efficiencies were greater than 99.999%, greater than 99.999%, and 100% (P = not significant) for the DAR Barrierbac S, the Baxter Airlife, and the Pall BB25A, respectively.
Among the three BFs studied, only the Pall BB25A completely prevented the passage of M. chelonae, thus protecting the anesthesia breathing circuit from mycobacterial contamination.
Women with chronic coronary disease are generally older than men and have more comorbidities but less atherosclerosis. We explored sex differences in revascularization, guideline-directed medical ...therapy, and outcomes among patients with chronic coronary disease with ischemia on stress testing, with and without invasive management.
The ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trial randomized patients with moderate or severe ischemia to invasive management with angiography, revascularization, and guideline-directed medical therapy, or initial conservative management with guideline-directed medical therapy alone. We evaluated the primary outcome (cardiovascular death, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest) and other end points, by sex, in 1168 (22.6%) women and 4011 (77.4%) men. Invasive group catheterization rates were similar, with less revascularization among women (73.4% of invasive-assigned women revascularized versus 81.2% of invasive-assigned men;
<0.001). Women had less coronary artery disease: multivessel in 60.0% of invasive-assigned women and 74.8% of invasive-assigned men, and no ≥50% stenosis in 12.3% versus 4.5% (
<0.001). In the conservative group, 4-year catheterization rates were 26.3% of women versus 25.6% of men (
=0.72). Guideline-directed medical therapy use was lower among women with fewer risk factor goals attained. There were no sex differences in the primary outcome (adjusted hazard ratio HR for women versus men, 0.93 95% CI, 0.77-1.13;
=0.47) or the major secondary outcome of cardiovascular death/myocardial infarction (adjusted HR, 0.93 95% CI, 0.76-1.14;
=0.49), with no significant sex-by-treatment-group interactions.
Women had less extensive coronary artery disease and, therefore, lower revascularization rates in the invasive group. Despite lower risk factor goal attainment, women with chronic coronary disease experienced similar risk-adjusted outcomes to men in the ISCHEMIA trial.
URL: http://wwwclinicaltrials.gov. Unique identifier: NCT01471522.
For opioid-tolerant patients, conventional patient-controlled analgesia dosing may be ineffective. We present a cardiac surgery patient with a history of significant opioid tolerance and prior ...episodes of severe postoperative pain. Using the patient's response to a large-dose fentanyl infusion in conjunction with a pharmacokinetic simulation, effective intraoperative and postoperative fentanyl plasma concentrations were achieved.
A preinduction fentanyl infusion used in conjunction with pharmacokinetic simulation can be a useful tool for assessing individual limits of opioid tolerance, as well as determining an appropriate dose for acute pain management in opioid-tolerant patients.
In order to reuse the same anesthesia breathing circuit for more than one patient, it has been proposed to add a breathing filter between the Y-piece and the artificial airway. The purpose of this ...study was to evaluate the in vivo bacterial filtration efficacy of an anesthesia filter in a usual clinical anesthesia setting.
A sterile DAR Barrierbac S breathing filter was inserted at the Y-piece of a sterile single-use anesthesia breathing circuit before induction of general anesthesia. At the end of anesthesia, the breathing circuit connector of the filter and of the endotracheal tube connector were cultured separately on growth media (chocolate and blood agar). These were incubated for 48 hr and bacterial identification was conducted using standard methods.
Bacterial cultures were negative on both sides of the filter membrane of 1842 of the 2001 filters studied. Cultures were positive on the patient side of 104 filters. In two of those, the same bacteria were found on both the circuit side and the patient side of the filter. Therefore these data indicate a clinical effectiveness of 99.9% (confidence interval, CI 95%, 99.6-99.998%), and an in vivo filtration efficacy of 98.08% (CI 95%, 92.54-99.67%).
Using the upper limit of the CI, it can be assumed that the practice of using a sterile DAR Barrierbac S breathing filter for every patient while reusing the anesthesia breathing circuit would result in a cross contamination rate of the breathing circuit lower than once every 250 cases.
While the standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered 3 weeks apart, some public health authorities are spacing these doses, raising concerns about ...efficacy. However, data indicate that a single dose can be up to 90% effective starting 14 days post-administration. To assess the mechanisms contributing to protection, we analyzed humoral and T cell responses three weeks after a single BNT162b2 dose. We observed weak neutralizing activity elicited in SARS-CoV-2 naive individuals but strong anti-receptor binding domain and spike antibodies with Fc-mediated effector functions and cellular CD4+ T cell responses. In previously infected individuals, a single dose boosted all humoral and T cell responses, with strong correlations between T helper and antibody immunity. Our results highlight the potential role of Fc-mediated effector functions and T cell responses in vaccine efficacy. They also provide support for spacing doses to vaccinate more individuals in conditions of vaccine scarcity.
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•Three weeks after the first BNT162b2 dose, weak neutralizing antibodies are elicited•These antibodies have robust Fc-mediated effector functions•Vaccination of individuals previously infected boosts humoral and cellular responses•Strong correlations between T helper cell and humoral responses are observed
Tauzin and Nayrac et al. characterize humoral and cellular responses 3 weeks after a single dose of mRNA BNT162b2 vaccine. They show, in SARS-CoV-2-naive individuals, that the antibodies elicited have weak neutralizing activity but potent Fc-mediated effector functions, and in SARS-CoV-2 previously infected individuals, that all responses are significantly boosted.
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