Capnography: assessing end-tidal CO2 levels

The purpose of this article is to describe the nurse's role in caring for patients with capnography. Capnography provides a continuous and non-invasive measure of arterial partial pressure of carbon dioxide (PaCO2) throughout the entire respiratory cycle. Used correctly, this technology assists the critical care nurse in providing adequate oxygenation and ventilation to the unstable patient.     

Adaptive buffering of breath-by-breath variations of end-tidal CO2 of humans

We have designed and implemented a computer-controlled system that uses an adaptive control algorithm (generalized minimum variance) to buffer the breath-by-breath variations of the end-tidal CO2 fraction (FETCO2) that occur spontaneously or are exaggerated in certain experimental protocols (e.g., induced hypoxia, any type of induced variations in the ventilatory pattern). Near the end of each breath, FETCO2 of the following breath is predicted and the inspired CO2 fraction (FICO2) of the upcoming breath is adjusted to minimize the difference between the predicted and desired FETCO2 of the next breath. The one-breath-ahead prediction of FETCO2 is based on an adaptive autoregressive with exogenous inputs (ARX) model: FETCO2 of a given breath is related to FICO2, FETCO2 of the previous breath, and inspiratory ventilation. Adequacy of the prediction is demonstrated using data from experiments in which FICO2 was varied pseudorandomly in wakefulness and sleep. The algorithm for optimally buffering changes in FETCO2 is based on the coefficients of the ARX model. We have determined experimentally the frequency of FETCO2 variations that can be buffered adequately by our controller, testing both spontaneous variations in FETCO2 and variations induced by hypoxia in young awake human subjects. The controller is most effective in buffering variations of FETCO2 in the frequency range of <0.1 cycle/breath. Some potential applications are discussed.     

Gastric carcinoma in young adults

Among 47 blood donors tested positive with HCV EIA 2.0 Abbott, 27 (57.4%) also reacted with four ?third-generation' EIAs. The presence of anti-HCV antibodies was confirmed with 3 different immunoblot assays in 16 of 27 sera (34.0%) while 10 samples (21.3%) had indeterminate profile with antibodies usually directed against structural core antigen. Anti-HCV core IgM response was found in 12 of 47 sera (25.5%) and HCV viremia detected by the polymerase chain reaction (PCR) procedure was observed in 15 samples (31.9%). A comparative study of the different markers confirmed a good correlation between a strong antibody response in EIAs and immunoblot assays and the presence of HCV RNA in the serum; only 2 immunoblot indeterminate samples were PCR positive. An association was observed between IgM antibodies against "core' epitopes and HCV RNA carriage: all IgM-positive sera were found positive by PCR. However, the direct detection of viral genome remains the best method for identifying HCV carriers in the blood donor population.     

Contamination sensitivity in young children.

In Experiment 1, to examine contamination sensitivity, children ages 36 to 47 months were shown juice that had been in contact with a cockroach. In contrast to previous research suggesting that young children do not have the cognitive prerequisites to understand the invisible nature of contamination, most children indicated that the juice was not good to drink even though the cockroach had been removed, leaving no trace. Children made accurate evaluations of others' responses to this type of incident and inferred actions to protect others. The purpose of Experiment 2 was to determine whether contamination sensitivity may be guided by an implicit knowledge of the distinction between appearance and reality. Children ages 30 to 42 months were presented with a piece of moldy bread. The bread was then covered by a breakfast spread. In contrast to a control group that was given fresh bread without mold, most responded that the bread would not be good to eat even after the mold was concealed by the spread. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased resting and exercise-induced oxidative stress in young IDDM men

The effects of local application of the 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide (CPBG), and i.p. administration of ethanol on the extracellular levels of dopamine (DA) in the ventral tegmental area (VTA) were studied using in vivo microdialysis. Adult female Wistar rats were implanted with microdialysis probes in the VTA at least 24 h before each experiment. Stable extracellular levels of DA (101 +/- 9 fmol/20 min) were established before initiating the experiments. Application of 10-250 microM CPBG through the microdialysis probe dose-dependently enhanced the extracellular concentrations of DA but did not alter the levels of either 3,4-dihydroxyphenylacetic acid or homovanillic acid in the dialysate. The effects of CPBG were reversible and dependent upon Ca2+. Co-perfusion with the 5-HT3 receptor antagonist, 3-tropanyl-indole-3-carboxylate (ICS 205-930), inhibited the effects of CPBG on enhancing extracellular DA levels. The i.p. administration of 2 g/kg ethanol significantly (p < 0.005) enhanced the levels of DA to 150% of baseline values; this ethanol-induced increase was prevented by local perfusion with 100 microM ICS 205-930. These results suggest that 5-HT3 receptors in the VTA are involved in regulating the somatodendritic release of DA and in mediating the stimulatory effects of ethanol on this neuronal system.     

Prothrombotic states associated with retinal venous occlusion in young adults

BACKGROUND: The etiology of retinal venous occlusion in young patients is not well understood although thrombosis does occur histologically. A search for the risk factors that may lead to thrombosis is highly desirable may contribute to our understanding of the pathogenesis of this complication and may improve our therapeutic strategies. METHODS: We studied 17 patients with retinal venous occlusion. All patients were under 45 years of age (mean 37.8 +/- 7.1). Antiphospholipid antibodies (APAs) and certain hemostatic factors were determined. The results obtained in these patients were compared to those of normal controls. RESULTS: We found APAs in 8 out of 17 patients compared to 5 out of 60 controls (p = 0.0002). In patients with major trunk occlusion, there was a trend for the presence of APAs in those with poor visual acuity at presentation. Deficiencies of the coagulation inhibitor proteins C and S and antithrombin III activities were detected in 6 patients, and reduced levels of Factor XII were found in 4 patients. Levels of hematocrit, erythrocyte sedimentation rate. Fibrinogen, alpha 1-globulin, and alpha 2-globulin were significantly higher in patients compared to the controls (p = 0.019; 0.014; 0.0001; 0.011; 0.047), indicating increased blood viscosity in patients with retinal venous occlusion. CONCLUSION: Prothrombotic changes in the form of APAs and/or deficiencies of coagulation inhibitors and Factor XII may contribute to the etiology of retinal venous occlusion in young adults. Young patients with retinal venous occlusion should be evaluated for these prothrombotic states.     

Retinal arterial occlusions in young adults

Stereotactic posteroventral pallidotomy can improve motor performance in Parkinson's disease. Interruption of inhibitory pallidal projections to ventrolateral thalamus, components of a cortical-basal ganglia motor loop allows for this clinical benefit. We hypothesized that pallidotomy would lead to increased movement related activity in motor cortical areas receiving projections from ventrolateral thalamus. This was tested in 6 Parkinson's disease patients who underwent stereotactic posteroventral pallidotomy. Each patient was imaged with positron emission tomography (PET) measures of regional cerebral blood flow (rCBF) during performance of a simple prehension task and at rest. Scans were acquired before and 17 weeks after surgery. After pallidotomy, movement-related changes of rCBF increased significantly in both the supplementary motor area (SMA) and premotor cortex but not in primary motor cortex. The results demonstrate the importance of pallidothalamic circuitry for regulating volitional movements and confirm that disruption of inhibitory input to the ventrolateral thalamus can augment movement-related activity in motor association areas.     

Pupillometry as a measure of visual sensitivity among infants, young children, and adults.

Proposes pupillometry as an objective measure of visual sensitivity for infants, young children, and adults. To study the possible close relationship between pupillary contraction and perceived brightness for infants and young children, photopic pupillary sensitivity was measured for 5 1-yr-olds, 5 3-yr-olds, and 5 adults. Results support the utility of pupillometry as a sensitivity measure for infants and children, based on the demonstrated close agreement between the children's and adults' data in the study and adult data obtained by more traditional psychophysical techniques. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between pain sensitivity and resting arterial blood pressure in patients with painful temporomandibular disorders

OBJECTIVE: Patients experiencing temporomandibular disorders (TMD) show greater sensitivity to painful stimuli than age- and gender-matched control subjects. This enhanced pain sensitivity may result, at least in part, from an alteration in pain regulatory systems that are influenced by resting arterial blood pressure. In this study, we examined the relationship between resting systolic blood pressure and pain perception in 64 female TMD and 23 age-matched pain-free female subjects. METHOD: Resting arterial blood pressure and measures of thermal and ischemic pain threshold and tolerance were determined for each participant. Subjective ratings of thermal pain evoked by suprathreshold noxious thermal stimuli (45-49 degrees C) using a magnitude matching procedure were also obtained for both groups. RESULTS: TMD patients had lower thermal and ischemic pain thresholds and tolerances than pain-free subjects (ps < .05). Both groups provided equivalent intensity ratings to suprathreshold noxious thermal stimuli. A median split of each group based on resting systolic blood pressure revealed an influence of blood pressure on both thermal and ischemic pain perception for the Pain-Free group. The Pain-Free high resting blood pressure subgroup had higher thermal pain tolerances, higher ischemic pain thresholds, and provided lower magnitude estimates of the intensity of graded heat pulses compared with the Pain-Free low blood pressure subgroup. A trend toward a significant effect of blood pressure level on ischemic pain tolerance was also observed for the Pain-Free group. In contrast to the Pain-Free group, blood pressure level did not influence ischemic or thermal pain perception for TMD patients. Similar to the lack of effect of resting blood pressure on experimental pain perception in TMD patients, resting blood pressure was not related to measures of clinical orofacial pain in TMD patients. CONCLUSIONS: These findings confirm our previous findings that TMD patients are more sensitive to noxious stimuli and suggest that painful TMD may result, at least in part, from an impairment in central pain regulatory systems that are influenced by resting arterial blood pressure.     

Gender differences in the sensitivity to posttraumatic stress disorder: An epidemiological study of urban young adults.

The authors examine the relationship between 2 separate but interrelated findings in the epidemiology of posttraumatic stress disorder (PTSD): women's greater PTSD risk following traumatic events and the sensitizing effects of a prior trauma on the PTSD response to a subsequent trauma. Data come from a representative sample of 1,698 young adults from a large U.S. city. Analysis was conducted on the subset exposed to traumatic events. Women's risk for PTSD following assaultive violence was higher than men's. When assaultive violence preceded a later nonassaultive trauma in women, there was an increased risk (relative risk = 4.9) for PTSD, which was not observed in men. The relative risk estimate in women was significantly higher than in men. These findings suggest that assaultive violence elicits women's PTSD response directly and by sensitizing them to the effects of subsequent traumatic events of lesser magnitude. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychopathology in young adults with congenital heart disease. Follow-up results

Non-steroidal anti-inflammatory drugs inhibit constitutive (COX-1) and induced cyclooxygenase (COX-2), blocking prostaglandin production. We have compared the effects on nociceptive reflexes of meloxicam, which is COX-2 selective, with indomethacin, which is non-selective, using an in vitro spinal cord preparation. Cords were taken from naive rats, and from rats with carrageenan-induced hyperalgesia of one hindpaw. Reflex thresholds were lower in carrageenan preparations. Superfusion with meloxicam (10-100 microM) dose-dependently inhibited baseline reflexes and wind-up in normal and carrageenan preparations, whereas indomethacin (100-300 microM) had no effect. Thus meloxicam inhibits spinal reflexes, whereas indomethacin does not, despite its high affinity for both COX isoforms. We conclude that meloxicam has spinal antinociceptive actions which cannot be explained by the current concept of COX inhibition.     

Conditioned-reflex facilitation in young and older adults

Young (18-30 years) and elderly (63-88 years) human subjects received 70 trials of single-cue classical eyeblink conditioning (paired group), or 70 explicitly unpaired presentations of the tone conditioned stimulus (CS) and airpuff unconditioned stimulus (unpaired group). Before and after conditioning, reflex-eliciting white noise and corneal airpuff stimuli were presented alone or paired with the CS to investigate the effects of conditioning on eyeblink reflex amplitude. The results showed increased conditioned responses in the paired group compared to the unpaired group for the young but not the elderly subjects. There was, however, evidence of conditioned facilitation of noise-elicited reflexes in both young and elderly subjects. These data indicate that conditioned facilitation of the startle reflex may be a sensitive indicator of classical conditioning processes in human subjects.     

Multiple-risk behaviour in adolescents and young adults

OBJECTIVES: This article examines the prevalence of four risk behaviours among teenagers and young adults: smoking, binge drinking, sex with multiple partners, and sex without a condom. DATA SOURCE: The data are from a Health Canada-sponsored supplement to the 1994/95 National Population Health Survey. The analysis is based on 905 respondents aged 15 to 19 and 1,055 respondents aged 20 to 24. ANALYTICAL TECHNIQUES: Prevalence estimates of the four risk behaviours were calculated for males and females in each age group. An index of multiple-risk behaviour was derived by summing the four risk behaviours. Hierarchical multiple regression was used to examine how sets of variables are related to multiple-risk behaviour. MAIN RESULTS: Multiple-risk behaviour was higher among young people who had never married, who were not students, and who did not live with a parent. Feeling distressed was positively linked with multiple-risk behaviour, while regular attendance at religious services was negatively linked with such conduct.     

Vaginal replacement in children and young adults

PURPOSE: Absence of the vagina in the pediatric population most commonly results from congenital abnormalities, such as the Mayer-Rokitansky syndrome but it may also be seen after treatment for pelvic tumors, such as rhabdomyosarcoma, and in patients who have had previous gender reassignment. We review our experience using bowel for vaginal replacement in a group of children and young adults to assess outcome and satisfaction. MATERIALS AND METHODS: From 1980 to 1996 we evaluated 31 patients 1 to 20 years old who required vaginal replacement. Presenting diagnoses included müllerian failure (the Mayer-Rokitansky syndrome) in 20 patients, androgen insensitivity syndrome in 5, rhabdomyosarcoma in 3, penile agenesis in 1, cloacal exstrophy in 1 and 1 previously separated conjoint twin. A questionnaire was given to 26 of the 31 patients to assess postoperative sexual function and satisfaction. RESULTS: A total of 33 bowel segments in 31 patients were used for vaginal reconstruction, including sigmoid colon in 20, ileum in 8 and cecum in 5. Of the 31 patients 20 were sexually active, 8 were married and 3 had been previously married and divorced. Only 1 patient described chronic dyspareunia. Three patients were on chronic home dilation, while 4 required sanitary pads for vaginal secretions. There were 8 complications in the 31 patients, including stenosis of the bowel segment in 6. Three patients required a second procedure after total stenosis of the small bowel vagina (2) and prolapse of the neovagina (1), which required retroperitoneal fixation. CONCLUSIONS: Experience with this group of patients leads us to believe that isolated bowel segments provide excellent tissue for vaginal replacement. Furthermore, we believe that colon segments, particularly sigmoid, are preferable to small bowel for creation of the neovagina. In many instances the small bowel mesentery may be too short to provide an adequate, tension-free anastomosis in the perineum, particularly in obese patients. Our results would also suggest that sexual activity is more compatible with isolated bowel segments for vaginal replacement than with any of the more traditional methods, such as passive dilations and split thickness skin graft vaginoplasty.     

碳酸氢钠沉淀镧及碳酸镧的结晶过程研究

以pH值原位测定法为基础,结合沉淀体积变化、沉淀粒度及外观形貌分析结果,对NaHCO3上学同淀镧的性能及碳酸镧的结晶过程进行了研究。结果表明：碳酸镧结晶活性区域位于低配比区0．541－2．828之间,而在高配比区其结晶是惰性的。同时还考察了搅拌对结晶过程的影响,讨论了NaHCO3沉淀镧时的沉淀反应和结晶化机理。并给出了相关的化学反应方程式。     

Endoscopic CO2 laser excision of large or recurrent laryngeal saccular cysts in adults

BACKGROUND: Most paediatric cardiac arrest studies have been conducted in the USA, where paramedics provide prehospital emergency care. We wanted to study the outcome of paediatric cardiac arrest patients in an emergency medical system which is based on physician staffed emergency care units. METHODS: We analysed retrospectively the files of 100 prehospital cardiac arrest patients from Southern Finland during a 10-year study period. The patients were less than 16 years of age. RESULTS: Fifty patients were declared dead on the scene (DOS) without attempted resuscitation, and cardiopulmonary resuscitation (CPR) was initiated in 50 patients. The sudden infant death syndrome was the most common cause of arrest in the DOS patients (68%) as well as in those receiving CPR (36%). Asystole was the initial cardiac rhythm in 70% of the patients in whom CPR was attempted. Resuscitation was successful in 13 patients, 8 of whom were ultimately discharged. Six of the patients survived with mild or no disability and 4 of them had near-drowning aetiology. In multivariate analysis, the short duration of CPR (< or = 15 min) was the only factor significantly associated with better survival. CONCLUSIONS: Although prehospital care was provided by physicians, the overall rate of survival was found to be equally poor as reported from systems with paramedics. The only major difference between physician- and paramedic-staffed emergency care units is the ability of physicians to refrain from resuscitation already on the scene when prognosis is poor.     

Effects of low-dose recombinant human insulin-like growth factor-I on insulin sensitivity, growth hormone and glucagon levels in young adults with insulin-dependent diabetes mellitus

Despite recent interest in the therapeutic potential of recombinant human insulin-like growth factor-I (rhIGF-I) in the treatment of diabetes mellitus, its mechanism of action is still not defined. We have studied the effects of low-dose bolus subcutaneous rhIGF-I (40 microg/kg and 20 microg/kg) on insulin sensitivity, growth hormone (GH) and glucagon levels in seven young adults with insulin-dependent diabetes mellitus (IDDM) using a randomized double-blind placebo-controlled crossover study design. Each was subjected to a euglycemic clamp (5 mmol/L) protocol consisting of a variable-rate insulin infusion clamp (6:00 PM to 8:00 AM) followed by a two-dose hyperinsulinemic clamp (insulin infusion of 0.75 mU x kg(-1) x min(-1) from 8 to 10 AM and 1.5 mU x kg(-1) x min(-1) from 10 AM to 12 noon) incorporating [6,6 2H2]glucose tracer for determination of glucose production/utilization rates. Following rhIGF-I administration, the serum IGF-I level (mean +/- SEM) increased (40 microg/kg, 655 +/- 90 ng/mL, P < .001; 20 microg/kg, 472 +/- 67 ng/mL, P < .001; placebo, 258 +/- 51 ng/mL). Dose-related reductions in insulin were observed during the period of steady-state euglycemia (1 AM to 8 AM) (40 microg/kg, 48 +/- 5 pmol/L, P = .01; 20 microg/kg, 58 +/- 8 pmol/L, P = .03; placebo, 72 +/- 8 pmol/L). The mean overnight GH level (40 microg/kg, 9.1 +/- 1.4 mU/L, P = .04; 20 microg/kg, 9.6 +/- 2.0 mU/L, P = .12; placebo, 11.3 +/- 1.7 mU/L) and GH pulse amplitude (40 microg/kg, 18.8 +/- 2.9 mU/L, P = .04; 20 microg/kg, 17.0 +/- 3.4 mU/L, P > .05; placebo, 23.0 +/- 3.7 mU/L) were also reduced. No differences in glucagon, IGF binding protein-1 (IGFBP-1), acetoacetate, or beta-hydroxybutyrate levels were found. During the hyperinsulinemic clamp conditions, no differences in glucose utilization were noted, whereas hepatic glucose production was reduced by rhIGF-I 40 microg/kg (P = .05). Our data demonstrate that in subjects with IDDM, low-dose subcutaneous rhIGF-I leads to a dose-dependent reduction in the insulin level for euglycemia overnight that parallels the decrease in overnight GH levels, but glucagon and IGFBP-1 levels remain unchanged. The decreases in hepatic glucose production during the hyperinsulinemic clamp study observed the following day are likely related to GH suppression, although a direct effect by rhIGF-I cannot be entirely discounted.