The effect of selenium source on the oxidative status and performance of broilers reared at standard and high ambient temperatures.

1. This study investigated the oxidative status of broilers fed diets containing selenium (Se) from 14 to 35 d of age and reared at two different constant temperatures. Measurements of oxidative status included blood glutathione peroxidase (GSH-Px) and plasma total antioxidant status (TAS). Other variables included feed intake (FI), weight gain (WG), feed conversion ratio (FCR), Se levels in breast and liver tissue, jejunal villus morphometry, percentage weight of organs in relation to body weight; apparent metabolisable energy adjusted for nitrogen (AMEn); dry matter retention (DMR); fat retention (FR) and nitrogen retention (NR).2. The experiment started at 14 d of age, when 240 birds were randomly allocated to 48 pens (12 pens in four rooms). Treatments included a control diet 1 (SFC; 209.4 g/kg CP and 12.98 MJ/kg ME and no added Se containing saturated fat); diet 2 (SFSe) the control plus 12.605 mg/kg Se additive; diet 3 (USFC) was a second control diet (208.2 g/kg CP and 13.10 MJ/kg ME with no added Se containing unsaturated fat as rapeseed oil); diet 4 (USFSe) was the latter control plus 12.605 mg/kg Se additive. Two rooms were kept at a standard temperature of 20°C (ST) and two rooms were kept at high temperature of 35°C (HT).3. A temperature x Se interaction existed for GSH-Px in birds reared at ST (P < 0.05), and these birds had the highest levels of Se in liver tissue (P < 0.05). Fat x Se interactions were evident in breast tissue with highest levels in USFSe (P < 0.05). Adding Se improved jejunal VH: CD in USFSe fed birds (P < 0.001).4. Birds reared at ST had higher FI and WG than those reared at HT (P < 0.001), and had lower FCR than those reared at HT (P < 0.05). AMEn (MJ/kg DM) and FR were higher in birds fed USF diets, and lowest in birds fed SF (P < 0.50 and P < 0.001 respectively). NR was highest in birds raised at ST (P < 0.50).5. Broiler growth performance was reduced by HT. Oxidative status and Se in liver tissue was improved by adding Se in both diets.

The effect of feeding different sources and levels of selenium on growth performance and antioxidant status of broilers raised at two different temperatures.

1. This study examined the effects of different dietary sources and levels of selenium (Se) on growth performance, hepatic and breast meat Se content, glutathione peroxidase (GSH-Px) activity and total antioxidant status (TAS) in blood, when fed to broilers from 14 to 35 d of age and reared at two different temperatures (20°C and 35°C). 2. Five hundred and sixty male Ross 308 broilers were reared in a single floor pen and fed the same proprietary starter diet from 0 to 14 d age (229.9 g/kg CP and 12.67 MJ/kg ME, without Se supplementation). 3. The experiment started at 14 d age, and the birds randomly assigned to 112 raised-floor pens (0.36 m2 area, 5 birds/pen). Each of the seven experimental diets were offered to birds in 16 pens within four rooms. Two rooms were at 20°C and two rooms were maintained at 35°C. The experimental diets were fed from 14 to 35 d age and contained 214.9 g/kg CP and 13.11 MJ/kg ME. The experimental diets were as follows; control diet containing background Se only (0.189 mg/kg; C); low level sodium selenite (0.376 mg/kg; LSS): high level sodium selenite (0.558 mg/kg; HSS); low level commercial B Traxim® Se (0.244 mg/kg) (LBT); high level B Traxim® Se (0.448 mg/kg; HBT); low level selenised yeast (0.290 mg/kg; LSY); high level selenised yeast (0.487 mg/kg; HSY). 4. Birds consumed more when raised at 20°C compared to birds reared at 35°C (P ≤ 0.05). Birds fed lower Se level reared at 35°C had higher weight gain versus those fed higher Se level (P < 0.05). Birds fed SY had the lowest feed intake, weight gain and FCE (P < 0.05). The greatest GSH-Px activity was observed in birds fed SS diets (P < 0.001). There were interactions between diet x level for TAS, which were highest in birds fed LBT compared to birds fed HBT (P < 0.05). Breast Se content was higher in birds fed HSY compared to LSY (P < 0.001). The highest hepatic Se was seen in birds fed SY and lowest in C (P < 0.001). 5. Birds fed BT diets showed similar levels of Se to those birds fed inorganic Se, and similar levels of GSH-Px to birds fed SY. Further comparative work with broilers fed BT and other Se supplemented diets may elucidate the findings from this report.

Effect of feeding different sources of selenium on growth performance and antioxidant status of broilers.

1. This study was conducted to determine the effect of different sources of selenium (Se) on breast and liver tissue deposition, apparent metabolisable energy (AME), growth performance and antioxidant status of broilers, measured as Se content in liver and breast tissues and glutathione peroxidase (GSH-Px) in blood, when used in 0-35 d broiler chicken diets. 2. A total of 200 male Ross 308 broilers were used in the feeding trial, which comprised two dietary phases, a starter from 0 to 21 d and finisher from 21 to 35 d of age. Four treatments with 10 replications each were used. A control diet (C) was formulated that was sufficient in protein and energy (230 and 215 g/kg of crude protein and 12.67 and 13.11 MJ/kg of metabolisable energy, respectively), for both phases, but contained background Se only from the feed ingredients. Diet 2 (IS) was supplemented with 10.35 g/t inorganic, elemental source of Se. Diet 3 (SY) was supplemented with 136.36 g/t selenised yeast, an organic source derived from Saccharomyces cerevisiae. Diet 4 (SS) was supplemented with 0.666 g/t sodium selenite, an inorganic source. 3. Birds fed the SY diet consumed less and weighed less than those fed IS or C (P < 0.05; 0-35 d of age), but there was no difference compared to birds fed SS diets. There were no differences in FCR or dietary AME between broilers fed different Se sources. All diets containing supplementary Se increased concentrations in the liver and breast muscle, and for GSH-Px levels in blood compared to birds fed the C diet (P < 0.001). Birds fed SY diets had greater Se levels in liver and breast tissues compared to birds fed any of the other diets (P < 0.001). 4. Diets supplemented with Se had variable effects on broiler growth performances and antioxidant status. Feeding Se from a yeast source has higher transfer into breast tissues. Feeding different sources and levels of Se to birds in a more challenging situation to induce oxidative stress may bring more conclusive results.

False-positive results on colorimetric carbon dioxide analysis in neonatal resuscitation: potential for serious patient harm.

A term infant requiring resuscitation was found to have a false-positive color change on a colorimetric carbon dioxide device as a result of administration of epinephrine via an endotracheal tube. Using models of direct application and vapor exposure with a test lung, we discovered that epinephrine, atropine, infasurf and naloxone may result in false-positive color change. This false-positive response may lead to delayed recognition of esophageal intubation.

Cardiovascular chronobiology: do you know what time it is?

Cardiovascular indices, such as blood pressure, heart rate, cardiac output, and fibrinolytic factors, vary over a 24-hour period. For example, nocturnal blood pressure may decrease to 30-50 mm Hg and heart rate to 25 beats per minute. In addition, these cardiovascular rhythms interact and may trigger a cardiovascular catastrophe, such as a myocardial infarction, sudden cardiac arrest, or stroke, with the highest risk during the first 6 hours after awakening and arising. Understanding the fluctuations in cardiovascular indices and the rhythmic increase in risk is crucial in assessing patients and developing a protective plan of care. This article discusses the cardiovascular rhythms and the rhythmic increase in risk for cardiovascular catastrophes. A framework demonstrating the interaction of these rhythms provides the basis for the development and exploration of interventions, including modification of activity and medications, and nursing actions to protect patients during periods of high cardiovascular risk.

Critical care nurses' knowledge of arterial pressure monitoring.

BACKGROUND: Direct monitoring of arterial blood pressure provides continuous, real-time information about patients' physiological status. Critical care nurses set up and maintain monitoring systems and use the obtained data to guide clinical decisions. Inaccurate measurements may lead to misdiagnosis and mismanagement. PURPOSE: To describe critical care nurses' knowledge in 3 content areas related to direct monitoring of arterial blood pressure: physiology, technical aspects, and waveform and data interpretation. METHODS: Via poster advertisements, 391 critical care nurses in 6 intensive care units at 2 hospitals were invited to complete an 18-item, criterion-referenced questionnaire on monitoring arterial blood pressure and a demographic data sheet. Summary statistics were used to analyze data from 68 subjects. Analysis of variance was used to determine if total and subset scores differed among demographic subgroups. RESULTS: Scores ranged from 11.1% to 61.1% correct answers, with a mean of 36.7% (SD, 11.8%). Item analysis indicated a knowledge deficit in all content areas at all cognitive levels. Questions with highest scores addressed waveform damping and using mean arterial pressure to guide treatment; lowest scores were related to dynamic response characteristics and reflected pressure waves. Mean scores did not differ among demographic subgroups. CONCLUSIONS: The results suggest a general knowledge deficit in arterial blood pressure monitoring. This study should be replicated on a larger scale to validate its findings and to improve the validity and reliability of the research tool. National research-based standards of practice for hemodynamic monitoring should be developed and disseminated among critical care nurses.

Using evidence-based approaches to strategically respond to the nursing shortage.

The purpose of this article is to describe how evidence-based methods were used to create a strategic plan for recruitment and retention of nursing staff. Collecting data on the nursing workforce, thorough review and critique of the literature, and linking the literature to strategic goals and imperatives were accomplished. The success of the strategic plan requires much more than an evidence-based approach, however. Indeed, success is largely dependent on a radical change in culture. The long view is to create a patient-centered culture where spiritual values are integrated with knowledge and skill, resulting in competent caring for patients and families. That vision requires the recruiting and retention of competent and caring nurses. To retain rather than recruit nurses, the organizational culture must become a good place within which to work. Espousing spiritual values is not enough. Current employees and newcomers must recognize these values in the behaviors of staff, managers, and leaders. Beyond evidence-based methods, values integration is critical. In the end, it is the values-based behaviors of people rather than the evidence or the strategic plan that should allow this system to effectively confront and manage the continuing nursing shortage.

Effect of the 30 degree lateral recumbent position on pulmonary artery and pulmonary artery wedge pressures in critically ill adult cardiac surgery patients.

BACKGROUND: Despite demonstrated benefits of lateral positioning, critically ill patients may require prolonged supine positioning to obtain reproducible hemodynamic measurements. OBJECTIVES: TO determine the effect of 30 degree right and left lateral positions on pulmonary artery and pulmonary artery wedge pressures after cardiac surgery in critically ill adult patients. METHODS: An experimental repeated-measures design was used to study 35 patients with stable hemodynamics after cardiac surgery. Subjects were randomly assigned to 1 of 2 position sequences. Pulmonary artery and pulmonary artery wedge pressures were measured in each position. RESULTS: Measurements obtained from patients in the 30 degree left lateral position differed significantly (all Ps < .05) from measurements obtained from patients in the supine position for pulmonary artery systolic, end-diastolic, and mean pressures. Pulmonary artery wedge pressures did not differ significantly; however, data were available from only 17 subjects. The largest mean difference in pressures between the 2 positions was 2.0 +/- 2.1 mm Hg for pulmonary artery systolic pressures, whereas maximum differences for end-diastolic and pulmonary artery wedge pressures were 1.4 +/- 2.7 mm Hg and 1.6 +/- 2.4 mm Hg, respectively. Clinically significant position-related changes in pressure occurred in 12 (2.1%) of 581 pressure pairs. Clinically significant changes occurred in end-diastolic pressure in 2 subjects and in pulmonary artery wedge pressure in 1 subject. CONCLUSIONS: In patients with stable hemodynamics during the first 12 to 24 hours after cardiac surgery, measurements of pulmonary artery and pulmonary artery wedge pressures obtained in the 30 degree lateral and supine positions are clinically interchangeable.

Cardiovascular chronobiology: implications for critical care nursing.

Critical care clinicians must consider known expected circadian rhythms when interpreting fluctuations in patients' hemodynamic values. As noted in the case study, knowledge of circadian rhythmicity in cardiovascular variables may help clinicians anticipate hemodynamic changes and develop and evaluate chronobiologically sensitive interventions, including prescriptions for activity, modification of the timing of medications, and provision of protective interventions for patients with disrupted rhythms. Felver provides excellent guidelines for the systematic review of possible causes for overt changes in circadian patterns. This review highlights the need to evaluate (1) the effect of disease progression on temporal patterns, (2) the patient's underlying endogenous rhythms, (3) the zeitgebers that may entrain the patient's biological rhythms (e.g., light, social cues, and sleep-wake cycles), and (4) how the zeitgebers change in a critical care environment. The body of literature on the rhythmic fluctuation of cardiovascular variables in healthy, young subjects is extensive. During the past 10 years, research on the chronobiologic fluctuations of numerous physiological variables (cardiovascular, pulmonary, hematologic, and endocrine) in critical illness has increased. As information on the fluctuations in critically ill patients increases, critical care clinicians will be challenged to develop and evaluate a chronobiologically sensitive plan of care for these patients.

Kinetic evidence for pentachlorophenol-dependent growth of a dehalogenating population in a pentachlorophenol- and acetate-fed methanogenic culture.

A method was developed to evaluate growth of a reductively dechlorinating bacterial population within a pentachlorophenol (PCP)- and acetate-fed, mixed, methanogenic culture. In 6- to 12-day experiments, a computer-monitored/feedback-controlled bioreactor was used to maintain constant pH, temperature, and acetate concentration, while transformation of multiple PCP additions was monitored. The potential at a platinum electrode, EPt, was not controlled externally, but was maintained constant at -0.25 +/- 0.002 V (vs. SHE) by iron sulfides in the medium and the activity of the culture. PCP was reductively dechlorinated at the ortho position, yielding 3, 4,5-trichlorophenol (3,4,5-TCP) via 2,3,4,5-tetrachlorophenol (2,3,4, 5-TeCP). Below an initial PCP concentration of 0.5 microM, PCP was transformed to 3,4,5-TCP within 3 to 6 h. Biomass concentration changes were small during this period, and PCP and 2,3,4,5-TeCP transformations were modeled as pseudo-first-order reactions. Increases in pseudo-first-order rate constants for PCP and 2,3,4, 5-TeCP were directly related to the amount of PCP transformed to 3,4, 5-TCP, suggesting enrichment of a PCP-catabolizing population. Moreover, rate constant increases were independent of the amount of acetate consumed, changes in the overall volatile suspended solids (VSS) concentration, and the experimental duration. When PCP was added to the reactor at increasingly shorter time intervals in an exponential pattern, pseudo-first-order rate constants increased exponentially. An average rate constant doubling time of 1.7 days (1. 4 to 2.3 d) was estimated. While the VSS concentration of the culture increased 60% in an 8-day period, pseudo-first-order rate constants increased by a factor of approximately 6. This large increase in transformation rate constants suggests growth of a bacterial population capable of using PCP and 2,3,4,5-TeCP as terminal electron acceptors.

Comparison of reactors for oxygen-sensitive reactions: reductive dechlorination of chlorophenols by vitamin b(12s).

Serum bottles are frequently used for studies of reductive dechlorination by vitamin B(12), but reducing conditions can be maintained only for several days. This time period is inadequate for evaluating the reductive dechlorination of some slow-reacting aromatic compounds. Sealed glass ampoules maintain reducing conditions for many months, but this method has the disadvantage of disallowing subsampling of the reaction mixture. A glass serum tube was modified for these experiments which not only maintained anoxic conditions for several days but also allowed subsamples to be removed during experiments. The modification was a restriction placed in the middle of the tube by heating in a flame, creating two chambers separated by a narrow neck. The lower chamber contained the oxygen-sensitive reaction mixture. The upper chamber, sealed with a septum and screw cap, was purged with purified nitrogen or argon introduced and vented through fused silica capillaries. Reductive dechlorination of chlorophenols by vitamin B(12) reduced with Ti(III) citrate was monitored in all three reactor types. Sealed ampoules maintained reducing conditions for up to 12 months. The two-chambered reactor maintained reducing conditions longer than the serum vials when frequent samples were taken.

Regiospecificity of chlorophenol reductive dechlorination by vitamin b(12s).

Vitamin B(12), reduced by titanium (III) citrate to vitamin B(12s), catalyzes the reductive dechlorination of chlorophenols. Reductive dechlorination of pentachlorophenol and of all tetrachlorophenol and trichlorophenol isomers was observed. Reaction of various chlorophenols with vitamin B(12) favored reductive dechlorination at positions adjacent to another chlorinated carbon, but chlorines ortho to the hydroxyl group of a phenol were particularly resistant to reductive dechlorination, even if they were also ortho to a chlorine. This resulted in a reductive dechlorination pattern favoring removal of para and meta chlorines, which differs substantially from the pattern exhibited by anaerobic microbial consortia.

Familial Sneddon's syndrome: clinical, hematologic, and radiographic findings in two brothers.

We present the clinical, hematologic, and radiographic findings in two brothers with Sneddon's syndrome (stroke and livedo reticularis) and antiphospholipid antibodies. Patient 1 had anticardiolipin antibody and patient 2 had lupus anticoagulant, which we detected only upon repeated blood testing. One should test for both anticardiolipin antibody and lupus anticoagulant and repeat the screenings before determining a Sneddon's syndrome patient's antiphospholipid antibody status. Both Sneddon's syndrome and the primary antiphospholipid antibody syndrome are potentially familial causes of stroke. In familial cases, an inherited predisposition to antiphospholipid antibody production may be involved in disease pathogenesis.

Analgesics for cardiac surgery patients in critical care: describing current practice.

BACKGROUND: In the last 10 years, the American Association of Critical-Care Nurses has twice ranked pain management as a priority issue for research and practice. Recent research findings suggest that undermedication of patients continues both in and out of critical care. Postoperative cardiac surgery patients have reported detailed recollections of pain experiences while in critical care, yet little is known about management of postoperative cardiac surgery pain. OBJECTIVE: The purpose of this study was to describe current practice related to analgesic prescription and administration for postoperative cardiac surgery patients in critical care. METHODS: Medical records of 80 adults undergoing cardiac surgery in two hospitals were randomly selected for review. Data pertaining to pain medications prescribed and doses administered for the day of surgery, first and second postoperative days were recorded for 66 eligible subjects. RESULTS: All but one patient had a prescription for intravenous morphine, hourly as needed. In addition, all patients had prescriptions for one or more oral analgesics as needed. Gender and age effects were noted for analgesic prescriptions. The average total amount of intravenous morphine given over the 3 days was 13.9 +/- 13.5 mg in an average of 4 +/- 3.7 doses. The average total number of acetaminophen with oxycodone tablets given over the 3 days was 5.8 +/- 5.4 tablets in an average of 3.6 +/- 3.0 doses. Age and hospital effects were noted in the administration of analgesics. CONCLUSIONS: The finding of small and infrequent analgesic doses is consistent with other studies conducted in and out of critical care. Important inconsistencies, or variations in practice, exist in both the prescription and administration of analgesics for postoperative cardiac surgery patients in the critical care setting.

The human immunodeficiency virus and nonmenstrual toxic shock syndrome: a female case presentation.

Toxic shock syndrome (TSS) generally is associated with tampon use among menstruating women. Descriptions from the early 1980's detailed this sudden, multisystem, frequently fatal disease. The bacterial agent, Staphylococcus aureus produced exotoxins, which were quickly identified as the cause of TSS as well as a host of other systemic, bacterial infections. While S. aureus has become one of the more common bacterial pathogens in patients with Acquired Immune Deficiency Syndrome (AIDS), staphylococcal toxin-related disorders rarely have been reported in individuals infected with Human Immunodeficiency Virus (HIV) or individuals diagnosed with AIDS. To date all published cases of TSS attendant with HIV involved homosexual, hemophiliac, or drug injecting male patients. This report describes a woman infected with HIV and diagnosed with the classic array of symptoms found in toxic-shock syndrome, and provides information specific to women and their experience with HIV infection.

Temporal patterns of heart rate and selected arrhythmias for 48 hours after cardiac surgery.

OBJECTIVE: To describe the temporal patterns of heart rate and arrhythmias in the immediate postoperative period following cardiac surgery. Six postoperative cardiac surgical patients with a mean age of 48.3 years were studied. DESIGN: Descriptive longitudinal design. SETTING: Cardiac surgical ICU. METHODS: Heart rate and arrhythmias were recorded continuously for 48 hours from a cardiac monitor using a Holter tape recorder. Environmental and treatment data were noted throughout data collection by trained nonparticipant observers. RESULTS: Mean heart rate and incidence of arrhythmias were different between the 2 study days; therefore, data were divided into two segments (A and B). These differences coincided with extubation in most cases. Individual subject cosinor analysis revealed 24-hour rhythms of heart rate in both segments in all subjects except segment B for one subject. Rhythms of shorter periods were also found. In segment A individual subjects' acrophases (peak times of fitted curves) occurred later than expected for subjects' prehospitalization sleep-wake schedule, whereas in segment B they occurred earlier. Cosinor analysis of arrhythmias revealed significant 24-hour rhythms in both segments in one of the three subjects with premature atrial complexes, two of the four subjects with premature ventricular complexes and both subjects with ventricular couplets. Four-hour rhythms were found in premature atrial complexes (n = 1), atrial tachycardia (n = 1) and premature ventricular complexes (n = 3). Acrophases for arrhythmias varied among patients. During segment B the 4-hour-rhythm acrophases in heart rate and arrhythmias were related to the timing of respiratory therapy. CONCLUSIONS: Temporal variations in heart rate could be identified in these six critically ill adults. Rhythm parameters changed during the first 48 hours after cardiac surgery. In those who had arrhythmias, some patients demonstrated temporal patterns in the incidence of selected arrhythmias. Further study is needed to describe the temporal patterns of heart rate and arrhythmias in varied groups of critically ill persons in a variety of settings.

Pediatric critical care nurses' knowledge of cardiac dysrhythmias.

OBJECTIVE: To describe pediatric critical care nurses' knowledge of dysrhythmias in critically ill pediatric patients and relate this knowledge level to certain demographic variables (education, nursing experience, certification, supplemental training, area of employment and geographic region of residence). DESIGN: A descriptive survey. SETTING: American Association of Critical-Care Nurses' 19 geographic regions of the United States. PARTICIPANTS: Of 1000 questionnaires mailed to pediatric critical care nurses who were members of the American Association of Critical-Care Nurses in 1991, 356 responses were received (a response rate of 36%). INTERVENTION: A criterion-referenced, self-administered test regarding pediatric dysrhythmias and a demographic sheet randomly mailed to 1000 pediatric critical care nurses. Test results were analyzed and compared with demographic variables. RESULTS: The mean total test score was 66%. Significantly higher total test scores and selected subtest scores were demonstrated in relationship to the following variables: increased age; certification in pediatric advanced life support, advanced cardiac life support or adult critical care; increased years of adult critical care experience; advanced dysrhythmia courses and dysrhythmia self-study; and perceived knowledge level above that of the advanced beginner. CONCLUSIONS: Pediatric critical care nurses' overall knowledge of dysrhythmias was low. Knowledge strengths included recognition of basic and life-threatening dysrhythmias and calculation of basic ECG measurements. Knowledge deficits included importance of sinus bradycardia in the neonate, appropriate intervention for life-threatening dysrhythmias and calculation of an irregular heart rate. These deficits should be considered when planning continuing education programs for pediatric critical care nurses.

Issues in methods and measurement of thermodilution cardiac output.

Criterion-related validity of the thermodilution cardiac output technique for cardiac output measurement has to have a high correlation (r = .91 to .98) with the direct Fick method, the gold standard of cardiac output measurement. Issues that can affect validity of the measurements include the position of the pulmonary artery catheter, the rate of injection of the indicator solution, the volume and temperature of the injectate, the timing of the injection of indicator solution during the respiratory cycle, the position of the subject, and the presence of concomitant infusions. Variation in measurement can be limited by considering the delivery system for the indicator solution, by recording time-temperature cardiac output curves, and by considering normal biologic variations.

Pulmonary artery pressure measurement: state of the art.

The measurement of pulmonary artery pressure is a highly complex skill. Numerous technical variables can affect the reliability and validity of hemodynamic measurements: zeroing, referencing and evaluating the dynamic response characteristics of the pressure system, expected pressure fluctuations, stabilization period, and the effects of position and ventilation. This article presents a review of the literature related to the technical aspects of pulmonary artery pressure measurement. Recommendations for practice are presented in a research-based protocol.