Nitrous oxide-based vs. nitrous oxide-free general anaesthesia and accidental awareness in surgical patients: an abridged Cochrane systematic review.

Accidental awareness during general anaesthesia can arise from a failure to deliver sufficient anaesthetic agent, or from a patient's resistance to an expected sufficient dose of such an agent. Awareness is 'explicit' if the patient is subsequently able to recall the event. We conducted a systematic review into the effect of nitrous oxide used as part of a general anaesthetic on the risk of accidental awareness in people over the age of five years undergoing general anaesthesia for surgery. We included 15 randomised controlled trials, 14 of which, representing a total of 3439 participants, were included in our primary analysis of the frequency of accidental awareness events. The awareness incidence rate was rare within these studies, and all were considered underpowered with respect to this outcome. The risk of bias across all studies was judged to be high, and 76% of studies failed adequately to conceal participant allocation. We considered the available evidence to be of very poor quality. There were a total of three accidental awareness events reported in two studies, one of which reported that the awareness was the result of a kink in a propofol intravenous line. There were insufficient data to conduct a meta- or sub-group analysis and there was insufficient evidence to draw outcome-related conclusions. We can, however, recommend that future studies focus on potentially high-risk groups such as obstetric or cardiac surgery patients, or those receiving neuromuscular blocking drugs or total intravenous anaesthesia.

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation: a Cochrane Systematic Review.

Difficulties with tracheal intubation commonly arise and impact patient safety. This systematic review evaluates whether videolaryngoscopes reduce intubation failure and complications compared with direct laryngoscopy in adults. We searched CENTRAL, MEDLINE, Embase and clinicaltrials.gov up to February 2015, and conducted forward and backward citation tracking. We included randomized controlled trials that compared adult patients undergoing laryngoscopy with videolaryngoscopy or Macintosh laryngoscopy. We did not primarily intend to compare individual videolaryngoscopes. Sixty-four studies (7044 participants) were included. Moderate quality evidence showed that videolaryngoscopy reduced failed intubations (Odds Ratio (OR) 0.35, 95% Confidence Interval (CI) 0.19-0.65) including in participants with anticipated difficult airways (OR 0.28, 95% CI 0.15-0.55). There was no evidence of reduction in hypoxia or mortality, but few studies reported these outcomes. Videolaryngoscopes reduced laryngeal/airway trauma (OR 0.68, 95% CI 0.48-0.96) and hoarseness (OR 0.57, 95% CI 0.36-0.88). Videolaryngoscopy increased easy laryngeal views (OR 6.77, 95% CI 4.17-10.98) and reduced difficult views (OR 0.18, 95% CI 0.13-0.27) and intubation difficulty, typically using an 'intubation difficulty score' (OR 7.13, 95% CI 3.12-16.31). Failed intubations were reduced with experienced operators (OR 0.32, 95% CI 0.13-0.75) but not with inexperienced users. We identified no difference in number of first attempts and incidence of sore throat. Heterogeneity around time for intubation data prevented meta-analysis. We found evidence of differential performance between different videolaryngoscope designs. Lack of data prevented analysis of impact of obesity or clinical location on failed intubation rates. Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a videolaryngoscope reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a videolaryngoscope affects time required for intubation.

A systematic review of information format and timing before scheduled adult surgery for peri-operative anxiety.

We included 34 trials with 3742 participants, identified through 6 database and supplementary searches (to May 2017): 29 were randomised; 4 were quasi-randomised and 1 was cluster-randomised. Disparate measurements and outcomes precluded meta-analyses. Blinding was attempted in only 6 out of 34 (18%) trials. A multimedia format, alone or in combination with text or verbal formats, was studied in 20/34 (59%) trials: pre-operative anxiety was unaffected in 10 out of 14 trials and reduced by the multimedia format in three; postoperative anxiety was unaffected in four out of five trials in which formats were compared. Multimedia formats increased knowledge more than text, which in turn increased knowledge more than verbal formats. Other outcomes were unaffected by information format. The timing of information did not affect pre-operative anxiety, postoperative pain or length of stay. In conclusion, the effects of pre-operative information on peri-operative anxiety and other outcomes were affected little by format or timing.

The physics of Martian weather and climate: a review.

The planet Mars hosts an atmosphere that is perhaps the closest in terms of its meteorology and climate to that of the Earth. But Mars differs from Earth in its greater distance from the Sun, its smaller size, its lack of liquid oceans and its thinner atmosphere, composed mainly of CO(2). These factors give Mars a rather different climate to that of the Earth. In this article we review various aspects of the martian climate system from a physicist's viewpoint, focusing on the processes that control the martian environment and comparing these with corresponding processes on Earth. These include the radiative and thermodynamical processes that determine the surface temperature and vertical structure of the atmosphere, the fluid dynamics of its atmospheric motions, and the key cycles of mineral dust and volatile transport. In many ways, the climate of Mars is as complicated and diverse as that of the Earth, with complex nonlinear feedbacks that affect its response to variations in external forcing. Recent work has shown that the martian climate is anything but static, but is almost certainly in a continual state of transient response to slowly varying insolation associated with cyclic variations in its orbit and rotation. We conclude with a discussion of the physical processes underlying these long- term climate variations on Mars, and an overview of some of the most intriguing outstanding problems that should be a focus for future observational and theoretical studies.

Systematic review and meta-analysis of enhanced recovery programmes in surgical patients.

BACKGROUND: Enhanced recovery programmes (ERPs) have been developed over the past 10 years to improve patient outcomes and to accelerate recovery after surgery. The existing literature focuses on specific specialties, mainly colorectal surgery. The aim of this review was to investigate whether the effect of ERPs on patient outcomes varies across surgical specialties or with the design of individual programmes. METHODS: MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials were searched from inception to January 2013 for randomized or quasi-randomized trials comparing ERPs with standard care in adult elective surgical patients. RESULTS: Thirty-eight trials were included in the review, with a total of 5099 participants. Study design and quality was poor. Meta-analyses showed that ERPs reduced the primary length of stay (standardized mean difference -1·14 (95 per cent confidence interval -1·45 to -0·85)) and reduced the risk of all complications within 30 days (risk ratio (RR) 0·71, 95 per cent c.i. 0·60 to 0·86). There was no evidence of a reduction in mortality (RR 0·69, 95 per cent c.i. 0·34 to 1·39), major complications (RR 0·95, 0·69 to 1·31) or readmission rates (RR 0·96, 0·59 to 1·58). The impact of ERPs was similar across specialties and there was no consistent evidence that elements included within ERPs affected patient outcomes. CONCLUSION: ERPs are effective in reducing length of hospital stay and overall complication rates across surgical specialties. It was not possible to identify individual components that improved outcome. Qualitative synthesis may be more appropriate to investigate the determinants of success.

Impacts of Heterogeneous Chemistry on Vertical Profiles of Martian Ozone.

We show a positive vertical correlation between ozone and water ice using a vertical cross-correlation analysis with observations from the ExoMars Trace Gas Orbiter's Nadir and Occultation for Mars Discovery instrument. This is particularly apparent during L S = 0°-180°, Mars Year 35 at high southern latitudes, when the water vapor abundance is low. Ozone and water vapor are anti-correlated on Mars; Clancy et al. (2016, https://doi.org/10.1016/j.icarus.2015.11.016) also discuss the anti-correlation between ozone and water ice. However, our simulations with gas-phase-only chemistry using a 1-D model show that ozone concentration is not influenced by water ice. Heterogeneous chemistry has been proposed as a mechanism to explain the underprediction of ozone in global climate models (GCMs) through the removal of HO x . We find improving the heterogeneous chemical scheme by creating a separate tracer for the HO x adsorbed state, causes ozone abundance to increase when water ice is present (30-50 km), better matching observed trends. When water vapor abundance is high, there is no consistent vertical correlation between observed ozone and water ice and, in simulated scenarios, the heterogeneous chemistry has a minor influence on ozone. HO x , which are by-products of water vapor, dominate ozone abundance, masking the effects of heterogeneous chemistry on ozone, and making adsorption of HO x have a negligible impact on ozone. This is consistent with gas-phase-only modeled ozone, showing good agreement with observations when water vapor is abundant. Overall, the inclusion of heterogeneous chemistry improves the ozone vertical structure in regions of low water vapor abundance, which may partially explain GCM ozone deficits.

Global Variations in Water Vapor and Saturation State Throughout the Mars Year 34 Dusty Season.

To understand the evolving martian water cycle, a global perspective of the combined vertical and horizontal distribution of water is needed in relation to supersaturation and water loss and how it varies spatially and temporally. The global vertical water vapor distribution is investigated through an analysis that unifies water, temperature and dust retrievals from several instruments on multiple spacecraft throughout Mars Year (MY) 34 with a global circulation model. During the dusty season of MY 34, northern polar latitudes are largely absent of water vapor below 20 km with variations above this altitude due to transport from mid-latitudes during a global dust storm, the downwelling branch of circulation during perihelion season and the intense MY 34 southern summer regional dust storm. Evidence is found of supersaturated water vapor breaking into the northern winter polar vortex. Supersaturation above around 60 km is found for most of the time period, with lower altitudes showing more diurnal variation in the saturation state of the atmosphere. Discrete layers of supersaturated water are found across all latitudes. The global dust storm and southern summer regional dust storm forced water vapor at all latitudes in a supersaturated state to 60-90 km where it is more likely to escape from the atmosphere. The reanalysis data set provides a constrained global perspective of the water cycle in which to investigate the horizontal and vertical transport of water throughout the atmosphere, of critical importance to understand how water is exchanged between different reservoirs and escapes the atmosphere.

Assimilation of Both Column- and Layer-Integrated Dust Opacity Observations in the Martian Atmosphere.

A new dust data assimilation scheme has been developed for the UK version of the Laboratoire de Météorologie Dynamique Martian General Circulation Model. The Analysis Correction scheme (adapted from the UK Met Office) is applied with active dust lifting and transport to analyze measurements of temperature, and both column-integrated dust optical depth (CIDO), τ ref (rescaled to a reference level), and layer-integrated dust opacity (LIDO). The results are shown to converge to the assimilated observations, but assimilating either of the dust observation types separately does not produce the best analysis. The most effective dust assimilation is found to require both CIDO (from Mars Odyssey/THEMIS) and LIDO observations, especially for Mars Climate Sounder data that does not access levels close to the surface. The resulting full reanalysis improves the agreement with both in-sample assimilated CIDO and LIDO data and independent observations from outside the assimilated data set. It is thus able to capture previously elusive details of the dust vertical distribution, including elevated detached dust layers that have not been captured in previous reanalyzes. Verification of this reanalysis has been carried out under both clear and dusty atmospheric conditions during Mars Years 28 and 29, using both in-sample and out of sample observations from orbital remote sensing and contemporaneous surface measurements of dust opacity from the Spirit and Opportunity landers. The reanalysis was also compared with a recent version of the Mars Climate Database (MCD v5), demonstrating generally good agreement though with some systematic differences in both time mean fields and day-to-day variability.

Multi-model Meteorological and Aeolian Predictions for Mars 2020 and the Jezero Crater Region.

Nine simulations are used to predict the meteorology and aeolian activity of the Mars 2020 landing site region. Predicted seasonal variations of pressure and surface and atmospheric temperature generally agree. Minimum and maximum pressure is predicted at Ls ∼ 145 ∘ and 250 ∘ , respectively. Maximum and minimum surface and atmospheric temperature are predicted at Ls ∼ 180 ∘ and 270 ∘ , respectively; i.e., are warmest at northern fall equinox not summer solstice. Daily pressure cycles vary more between simulations, possibly due to differences in atmospheric dust distributions. Jezero crater sits inside and close to the NW rim of the huge Isidis basin, whose daytime upslope (∼east-southeasterly) and nighttime downslope (∼northwesterly) winds are predicted to dominate except around summer solstice, when the global circulation produces more southerly wind directions. Wind predictions vary hugely, with annual maximum speeds varying from 11 to 19 ms - 1 and daily mean wind speeds peaking in the first half of summer for most simulations but in the second half of the year for two. Most simulations predict net annual sand transport toward the WNW, which is generally consistent with aeolian observations, and peak sand fluxes in the first half of summer, with the weakest fluxes around winter solstice due to opposition between the global circulation and daytime upslope winds. However, one simulation predicts transport toward the NW, while another predicts fluxes peaking later and transport toward the WSW. Vortex activity is predicted to peak in summer and dip around winter solstice, and to be greater than at InSight and much greater than in Gale crater. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11214-020-00788-2.

Splenic injury as a rare complication of colonoscopy.

Injury resulting from colonoscopy is rare. Bleeding and perforation are the most serious complications. The case history is described of a patient who developed splenic rupture following screening colonoscopy with associated polypectomy.

NPY-induced feeding: pharmacological characterization using selective opioid antagonists and antisense probes in rats.

The ability of neuropeptide Y to potently stimulate food intake is dependent in part upon the functioning of mu and kappa opioid receptors. The combined use of selective opioid antagonists directed against mu, delta or kappa receptors and antisense probes directed against specific exons of the MOR-1, DOR-1, KOR-1 and KOR-3/ORL-1 opioid receptor genes has been successful in characterizing the precise receptor subpopulations mediating feeding elicited by opioid peptides and agonists as well as homeostatic challenges. The present study examined the dose-dependent (5-80 nmol) cerebroventricular actions of general and selective mu, delta, and kappa1 opioid receptor antagonists together with antisense probes directed against each of the four exons of the MOR-1 opioid receptor gene and each of the three exons of the DOR-1, KOR-1, and KOR-3/ORL-1 opioid receptor genes upon feeding elicited by cerebroventricular NPY (0.47 nmol, 2 ug). NPY-induced feeding was dose-dependently decreased and sometimes eliminated following pretreatment with general, mu, delta, and kappa1 opioid receptor antagonists. Moreover, NPY-induced feeding was significantly and markedly reduced by antisense probes directed against exons 1, 2, and 3 of the MOR-1 gene, exons 1 and 2 of the DOR-1 gene, exons 1, 2, and 3 of the KOR-1 gene, and exon 3 of the KOR-3/ORL-1 gene. Thus, whereas the opioid peptides, beta-endorphin and dynorphin A(1-17) elicit feeding responses that are respectively more dependent upon mu and kappa opioid receptors and their genes, the opioid mediation of NPY-induced feeding appears to involve all three major opioid receptor subtypes in a manner similar to that observed for feeding responses following glucoprivation or lipoprivation.

Effect of menstrual cycle on HIV-1 levels in the peripheral blood and genital tract. WHS 001 Study Team.

OBJECTIVE: To assess the variation in HIV-1 over the menstrual cycle, including RNA levels in the female genital tract, plasma HIV-1-RNA levels, CD4 cell counts, and culturable virus. DESIGN: A prospective analysis of 55 HIV-1-infected women. METHODS: Blood and genital tract specimens were collected weekly over 8 weeks, spanning two complete menstrual cycles. Applying repeated-measures models that used menses as the reference level, the variation in viral RNA levels was compared in endocervical canal fluid and cells (collected by Sno-strips and cytobrush, respectively) and ectocervicovaginal lavage (CVL) fluid. Repeated-measures models were also used to assess the variation in plasma CD4 cell counts and viral load. RESULTS: Shedding patterns differed among the three sampling methods, independent of genital tract co-infections. Genital tract HIV-1-RNA levels from CVL fluid and endocervical canal cytobrush specimens were highest during menses and lowest immediately thereafter (P = 0.001 and P = 0.04). The HIV-1-RNA level in endocervical canal fluid was highest in the week preceding menses (P = 0.003). The menstrual cycle had no effect on blood levels of RNA (P = 0.62), culturable virus (P = 0.34), or CD4 cell counts (P = 0.55). HIV-1-RNA levels were higher in endocervical canal fluid than in peripheral blood plasma during the late luteal phase (P = 0.03). CONCLUSION: HIV-1-RNA levels vary with the menstrual cycle in the female genital tract but not the blood compartment. HIV-1-RNA levels are higher in endocervical canal fluid than in blood plasma. These findings may have important implications for sex-specific pathogenesis, heterosexual transmission, and contraceptive hormone interventions in HIV-1-infected women.

Cloning of the mouse somatostatin receptor subtype 5 gene: promoter structure and function.

Somatostatin is a peptide hormone whose actions are mediated by five somatostatin receptor subtypes (sstl-5). In the pituitary, somatostatin inhibits TSH release from thyrotropes and GH release from somatotropes. We have shown that sst5 transcripts and protein are induced by thyroid hormone in TtT-97 thyrotropic tumors. To map sequences responsible for promoter activity in pituitary cells, we cloned the mouse sst5 coding region of 362 amino acids and 12 kb of upstream DNA. Initial transfection studies in TtT-97 or GH3 cells mapped high levels of basal promoter activity to a 5.6-kb fragment upstream of the translational start, whereas shorter genomic fragments had low activity. To identify the transcriptional start site we used 5' RACE with TtT-97 poly A+ RNA and a sst5 antisense coding region primer. Sequence comparison between the complementary DNA and the gene revealed that the mouse sst5 gene contains 3 exons and 2 introns. The entire coding region was contained in exon 3. Two differently sized RACE products demonstrated alternate exon splicing of two untranslated exons in TtT-97 cells. A promoter fragment from -290/+48 linked to a luciferase reporter demonstrated 600- and 900-fold higher activity over a promoterless control in GH3 mammosomatotropes and TtT-97 thyrotropes, respectively, whereas a larger fragment extending to -6400 exhibited no additional promoter activity. Cloning of the sst5 gene will facilitate the mapping of basal and regulated responses at the transcriptional level.

Cigarettes, alcohol, marijuana, other risk behaviors, and American youth.

Increases in adolescent marijuana and other drug use have created widespread concern. One theory argues that increased use of cigarettes and alcohol among younger adolescents leads to greater use of marijuana which, in turn, leads to subsequent use of other drugs (e.g. cocaine, heroin, hallucinogens). Detractors of this theory claim that use of these substances is a symptom of a larger set of destructive behaviors (e.g. violence, suicide, promiscuous sex), and marijuana has no independent effect on the use of other more serious drugs. The authors examined whether, for high school seniors, early use of cigarettes, alcohol and marijuana has an independent effect on more serious drug use even when other behaviors are considered. Using the 1995 Youth Risk Behavior Survey (n = 2871) and logistic analysis, after accounting for selected other behaviors, seniors using cigarettes before age 13 were 3.3 (95% C.I. 2.3,4.6) times likelier to have used marijuana than ones who never smoked; for alcohol, the odds ratio was 4.5 (2.6,7.7). Seniors using marijuana before the age of 14 were 7.4 times (4.0,13.6) likelier to have used other drugs. Though no causal effect is demonstrated, cigarette and alcohol use was associated with the likelihood of marijuana use; marijuana use was associated with the likelihood of other drug use, even after selected other risk and protective behaviors were considered.

Prevention and management of contractures in patients with burns of the neck.

Two hundred patients with neck burns were analyzed to determine the incidence of contractures. It was found that only 8 per cent of patients with second degree burns had contractures, all of which were mild. Both the overall incidence of cervical contractures in patients with third degree neck burns and their severity can be decreased by the use of a custom-formed isoprene splint. Splinting should begin as soon as possible after the burn and continue until scar maturation is complete.

Burn injuries of the eyelids.

Burns of the eyelid and surrounding structures are relatively uncommon in spite of a high incidence of thermal injuries involving the face. The etiologic factors, circumstances that precipitated the injury, and the anatomical features unique to the eyelid and adnexal area may conceivably account for the low incidence. The basic aims in reconstructing deformities must include primarily measures of protecting corneal exposure and relieving epiphora. Early reconstruction of other deformities such as epicanthal folds, palpebral stenosis, and missing eyebrows and eyelashes should be discouraged because of frequent recurrence of deformities due to contracting scars and scar hypertrophy.

A histological study of the lower tarsus and the significance in the surgical management of a involutional (senile) entropion.

The dimension of the lower tarsus diminishes with aging. Changes in the number and size of the meibomian glands and in the character of intermingling fibroconnective tissues are thought to be responsible. Furthermore, such alterations of the structural integrity play an important role in the pathogenesis of entropion encountered commonly in the elderly. We have advocated the use of an autogenous cartilage graft harvested from the ear to correct the deformity, especially in instances where the conventional methods of correction have failed.

Relative hypoxemia during rhytidoplasty.

The results of blood gas analyses in 24 patients who had a rhytidoplasty under local anesthesia indicated that a moderate degree of hypoxemia can be elicited in these patients when they have had standard doses of the usual sedatives. While the acid-base abnormalities were generally corrected spontaneously, the extent of the hypoxemia can be aggravated further by the additional use of diazepam during the operation. Therefore, over-sedation of such a patient during the operation, without a secured airway, must be avoided. Additionally, we recommend deep breathing at frequent intervals, with or without supplemental oxygen through a high flow system.

Retrobulbar hemorrhage.

Retrobulbar hemorrhage is a rare complication of orbital trauma or surgery. Although the process is usually self-limiting, infrequently visual impairment may result. Various methods for relieving the associated intraocular hypertension (caused by the extraocular compression posteriorly) have been suggested. The effectiveness of some remains questionable. To reassess the effectiveness of conservative management of this problem, we reviewed the medical records of all 10 patients who had had retrobulbar hemorrhage at our institution during the past 8 years. Additionally, we did an experimental study on rabbits to evaluate the visual effects of a transient but abnormally high intraorbital pressure. The results are reported.

Reconstruction of the burned palm: full-thickness versus split-thickness skin grafts--long-term follow-up.

The long-term results of full-thickness (N = 11) and split-thickness (N = 14) skin grafts for reconstitution of the palmar surface following release of palmar burn scar contractures in pediatric patients are compared. Patients treated with full-thickness skin grafts required 1.2 +/- 0.4 operations (mean +/- SD). Patients treated with split-thickness skin grafts required 1.3 +/- 0.6 operations (mean +/- SD). No significant difference in the number of operative procedures was noted. No functional difference existed between the two groups. The use of split-thickness skin grafts provided comparable function without increased operative procedures and was less deforming. Increased use of split-thickness skin grafts following release of palmar burn scar contractures in pediatric patients should be considered.