A prospective randomised controlled trial comparing tracheal intubation plus manual in‐line stabilisation of the cervical spine using the Macintosh laryngoscope vs the McGrath® Series 5 videolaryngoscope

Cervical spine immobilisation can make direct laryngoscopy difficult, which might lead to airway complications. This randomised control trial compared the time to successful intubation using either the Macintosh laryngoscope or the McGrath^® Series 5 videolaryngoscope in 128 patients who had cervical immobilisation applied. Intubation difficulty score, Cormack & Lehane laryngoscopic view, intubation failures, changes in cardiovascular variables and the incidence of any complications were recorded. The mean (SD) successful intubation time with the Macintosh laryngoscope was significantly shorter compared with the McGrath laryngoscope, 50.0 (32.6) s vs 82.7 (80.0) s, respectively (p = 0.0003), despite the McGrath laryngoscope's having a lower intubation difficulty score and a superior glottic view. There were five McGrath laryngoscope intubation failures, three owing to difficulty in passing the tracheal tube and two to equipment malfunction. Equipment malfunction is a major concern as a reliable intubating device is vital when faced with an airway crisis.     

Intracellular cations and diuretic therapy following acute myocardial infarction

In a controlled, prospective, randomized study of the effects of diuretic therapy on serum, lymphocyte, and erythrocyte potassium, magnesium, and calcium concentrations, 155 patients were followed up for six months after experiencing acute myocardial infarction. Of these, 48 patients received furosemide and potassium; 37 patients received hydrochlorothiazide and amiloride hydrochloride; and 70 patients did not require diuretics. Lymphocyte and erythrocyte cation concentrations were all statistically significantly lower in the furosemide-treated patients when compared with the patients in the nondiuretic-therapy group or the hydrochlorothiazide-amiloride-treated group, with no change in serum levels. Since the combination of low intracellular potassium and magnesium concentrations in patients with recent myocardial infarction may be of importance in the cause of arrhythmias, we suggest that potassium- (and magnesium-) sparing diuretics be used in the treatment of patients, when necessary, unless their diuretic needs cannot be met by such agents.     

Platelet adenylate cyclase and phospholipase C activity in posttraumatic stress disorder

Adenylate cyclase and phospholipase C activity were examined in platelet membranes obtained from 19 male subjects with combat-related posttraumatic stress disorder (PTSD) and 35 age- and gender-matched healthy controls. Basal and forskolin-stimulated adenylate cyclase activity were significantly lower in the PTSD group whereas aluminum chloride plus sodium fluoride (AlCl3/NaF)- and prostaglandin E1 (PGE1)-stimulated responses were normal. There was no difference in phospholipase C activity between the two groups. The lower basal and forskolin-stimulated adenylate cyclase responses replicate a previous report and suggest that PTSD may be associated with an abnormality of the catalytic subunit of the receptor-adenylate cyclase complex.     

Relationship between sleep inertia and sleepiness: cumulative effects of four nights of sleep disruption/restriction on performance following abrupt nocturnal awakenings

Performance deficits are usually evident following both extended wakefulness (sleep deprivation effects) and immediately upon awakening from sleep (sleep inertia effects). In order to determine whether sleep inertia effects are qualitatively different from sleep deprivation effects, performance on addition tests, Stanford Sleepiness Scale (SSS) ratings, and return-to-sleep latencies (RSLs) were assessed during four nights of sleep disruption/restriction. Eight subjects were polygraphically monitored in the sleep laboratory for five consecutive nights, from 2400 to 0700. On the last four nights (after an adaptation night) subjects were awakened at 0040, 0140, 0240, 0340, 0440, and 0540 for a 20-min test session. Sleepiness ratings and performance on 5-min addition tests were measured at 1.5, 7.5, and 13.5 min post-awakening, and RSL was measured at the end of each test session. Analysis of addition test performance across nights revealed that both speed and accuracy of calculations were adversely affected by the sleep disruption/restriction procedure, indicating that increasing sleepiness exacerbates sleep performance deficits upon awakening. Although divergence of SSS ratings and addition test performance across nights was suggestive, there was no conclusive evidence that sleep inertia is qualitatively different from "typical" sleepiness.     

Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness

Prolonged sleep loss impairs alertness, vigilance and some higher-order cognitive and affective capacities. Some deficits can be temporarily reversed by stimulant medications including caffeine, dextroamphetamine, and modafinil. To date, only one study has directly compared the effectiveness of these three compounds and specified the doses at which all were equally effective in restoring alertness and vigilance following 64 h of wakefulness. The present study compared the effectiveness of these same three stimulants/doses following a less extreme period of sleep loss (i.e., 44 h). Fifty-three healthy adults received a single dose of modafinil 400 mg ( n  =   11), dextroamphetamine 20 mg ( n  =   16), caffeine 600 mg ( n  =   12), or placebo ( n  =   14) after 44 h of continuous wakefulness. After 61 h of being awake, participants obtained 12 h of recovery sleep. Psychomotor vigilance was assessed bi-hourly during waking and following recovery sleep. Relative to placebo, all three stimulants were equally effective in restoring psychomotor vigilance test speed and reducing lapses, although the duration of action was shortest for caffeine and longest for dextroamphetamine. At these doses, caffeine was associated with the highest percentage of subjectively reported side-effects while modafinil did not differ significantly from placebo. Subsequent recovery sleep was adversely affected in the dextroamphetamine group, but none of the stimulants had deleterious effects on postrecovery performance. Decisions regarding stimulant selection should be made with consideration of how factors such as duration of action, potential side-effects, and subsequent disruption of recovery sleep may interact with the demands of a particular operational environment.     

Socializing by Day May Affect Performance by Night: Vulnerability to Sleep Deprivation is Differentially Mediated by Social Exposure in Extraverts vs Introverts

Study Objectives:

To examine the effects of socially enriched versus socially impoverished environments on performance and alertness decline during sleep deprivation in extraverts versus introverts.

Design:

Participants (n = 29 men, n = 19 women) were assigned to socially enriched (n = 24; 13 introverts, 11 extraverts) or socially impoverished (n = 24; 12 introverts, 12 extraverts) conditions (activities matched) for 12 hours (1000–2200) on Day 1 followed by 22 hours of sleep deprivation (2200-2000; 36 h awake total), monitored by actigraphy. The median split of volunteers'' Eysenck Extraversion scores was used for extravert/introvert categorization. The Psychomotor Vigilance Task (PVT), modified Maintenance of Wakefulness Test (MWT), and Stanford Sleepiness Scale (SSS) were administered every 2 hours throughout. PVT speed, transformed lapses, modified MWT sleep-onset latency, and SSS were analyzed using mixed-model analyses of variance, with covariates of age and total actigraphic activity during enrichment or impoverishment.

Setting:

Residential sleep/performance testing facility.

Participants:

Forty-eight healthy adults (aged 18–39).

Interventions:

Twelve hours of socially enriched or isolated environments in extraverts and introverts prior to sleep deprivation.

Results

Social experience interacted with personality type to affect alertness and vigilance. Social enrichment, as compared with social impoverishment, was associated with more PVT lapses at 04:00 overall. Similarly, following social enrichment, PVT speed was significantly slower among extraverts than among introverts during sleep deprivation, but no personality-group differences emerged following social impoverishment. MWT sleep latency and SSS subjective sleepiness did not show significant personality or social-condition effects during sleep deprivation.

Conclusions:

The effect of social exposure on vulnerability or resiliency to sleep deprivation was modulated by introversion and extraversion. Extraverts exposed to social environments were more vulnerable to subsequent sleep deprivation than were introverts.

Citation:

Rupp TL; Killgore WDS; Balkin TJ. Socializing by day may affect performance by night: vulnerability to sleep deprivation is differentially mediated by social exposure in extraverts vs introverts. SLEEP 2010;33(11):1475-1485.     

Stability and viscosity of a flavored omeprazole oral suspension for pediatric use.

PURPOSE: The stability and viscosity of preparations of a commercially available, flavored, immediate-release powder for oral suspension (omeprazole-sodium bicarbonate) during refrigerator and room temperature storage were investigated. METHODS: Omeprazole-sodium bicarbonate 20-mg packets were suspended to initial omeprazole concentrations of 0.6 and 2 mg/mL, and omeprazole-sodium bicarbonate 40-mg packets were suspended to initial omeprazole concentrations of 1.2, 2, 3, and 4 mg/mL. Suspensions were stored at 4 degrees C in darkness (refrigerated) or 22-25 degrees C (room temperature) in light for one week. A third set of suspensions was stored refrigerated for one month. Omeprazole's stability was quantified after 0, 6, 12, 24, 48, and 168 hours in one-week samples and after 0, 7, 14, 21, and 28 days in one-month samples using high-pressure liquid chromatography. Viscosities of refrigerated suspensions were measured after 0, 1, and 7 days. RESULTS: Refrigerated suspensions retained >98% and >96% of their initial omeprazole concentrations after one week and one month, respectively. Stability of room temperature suspensions was concentration dependent. After one week, the 0.6- and 1.2-mg/mL suspensions retained 87.2% and 93.1% of their respective initial omeprazole concentrations, whereas the 2-, 3-, and 4-mg/mL suspensions retained >97% of their initial omeprazole concentrations. Suspension viscosities varied 10-fold over the concentrations studied, but all were within the viscosity ranges of other commercially available oral suspensions. Prolonged refrigeration did not increase the suspensions' viscosities. CONCLUSION: Omeprazole-sodium bicarbonate suspensions of 0.6-4 mg/mL omeprazole were stored at 4 degrees C in darkness for up to 28 days. The viscosities of refrigerated suspensions did not increase over 7 days. Except for the 0.6 mg/mL preparations, suspensions stored at room temperature in the light retained >90% of their initial omeprazole content after 7 days, despite turning yellow.     

Behavioral Control Over Sleeping Respiration in Normals for Ten Consecutive Nights

Behavioral control over sleeping respiration in 5 healthy college students was tested over 10 consecutive nights and 1 additional night 1–2 weeks later. Participants were polygraphically recorded each night and the records scored using standardized criteria. They were informed while awake that tones (.5 s on/off, 4000 Hz) would be presented to them (variable interval schedule, X?=7.5 min) during nighttime sleep and that their task was to terminate them by taking a deep breath. Behavioral control over respiration was maintained over the 10 nights. Latency to respond gradually increased over the first 5 nights and then leveled out for the remaining 5 nights. On the test night, 1–2 weeks following Night 10, latency to respond was similar to Nights 1 and 2. Percentage of time spent in each sleep stage and the pattern of arousals to tones and responses were similar to earlier reports (more stage 1, less stage 3–4; frequent arousals). It was concluded that behavioral control over sleeping respiration can be obtained and maintained in normal college students over at least 10 nights but a limiting factor may be the increase in response latency.     

Analysis of inferior venacavography before greenfield filter placement

The value of routine preoperative inferior venacavography through a femoral approach was assessed in 64 patients who required a Greenfield inferior vena cava filter. Nearly 11% of the patients had an abnormality, for example, duplication of the inferior vena cava, circumaortic renal vein, interrupted or discontinuous inferior vena cava, and so on, requiring an alternate approach to placement. No deaths or complications occurred upon recognition of the anatomic variant before filter placement. In three of the seven abnormalities encountered, adequate visualization and filter placement could only have been accomplished through femoral catheterization. Preoperative cavograms before Greenfield filter placement should be routinely performed using a femoral approach in the absence of contraindications to this technique.