The effects of different analgesic regimens on transcutaneous CO2 after major surgery.

Ventilatory impairment may be detected by a rise in transcutaneous carbon dioxide levels (PtcCO(2)). This observational study assessed the clinical utility of PtcCO(2) monitoring in the postoperative period, and quantified the effect of different peri-operative analgesic regimens on postoperative respiratory function. Following pre-operative baseline PtcCO(2) recording, continuous PtcCO(2) monitoring was performed in 30 patients after major colorectal surgery for up to 24 h. Mean postoperative values of PtcCO(2) were 1.3 kPa (95% CI 1.0-1.5) higher than pre-operative values (p < 0.001). Patients receiving intravenous opioid patient controlled analgesia had a significantly higher elevation in postoperative PtcCO(2) compared to patients receiving epidural infusion analgesia, 1.8 kPa (CI 1.5-2.1) vs 0.7 kPa (CI 0.5-0.9) respectively (p < 0.001). The mean rise in PtcCO(2) following a single intravenous bolus of morphine delivered via PCA was 0.05 kPa (SEm 0.01), peaking at 12 min post-dose. The transcutaneous capnometer successfully recorded data for 98% of the total time it was applied to patients.

Randomised comparison of partial liquid ventilation, nebulised perfluorocarbon, porcine surfactant, artificial surfactant, and combined treatments on oxygenation, lung mechanics, and survival in rabbits after saline lung lavage.

OBJECTIVE: To compare gas exchange, lung mechanics, and survival to 12 h in surfactant-depleted lung-injured rabbits, treated with partial liquid ventilation (PLV) with perfluorocarbon, nebulised perfluorocarbon, and porcine or artificial surfactant. DESIGN: Prospective randomised controlled study. SETTING: Animal laboratory, University of Edinburgh, UK. SUBJECTS: Eighty-two adult female New Zealand white rabbits with surfactant deficiency and acute lung injury induced by repeated saline lavage. INTERVENTIONS: Animals were randomised to one of seven treatments: (a) control (n = 20); (b) PLV with perfluorocarbon PF 5080 (n = 12); (c) nebulised PF 5080 (n = 10); (d) artificial surfactant (n = 10); (e) porcine surfactant (n = 10); (f) artificial surfactant+PLV (n = 10); (g) porcine surfactant+PLV (n = 10). MEASUREMENTS AND MAIN RESULTS: Arterial blood gases and dynamic compliance (Cdyn) were measured hourly until 12 h. Oxygenation was improved by PLV, porcine surfactant, porcine surfactant+PLV and artificial surfactant+PLV. Cdyn improved after treatment with PLV, porcine surfactant and PLV+porcine surfactant. Survival was greater with PLV and artificial surfactant+PLV. Neither nebulised PF 5080 nor artificial surfactant had a detectable effect. CONCLUSIONS: PLV, porcine surfactant and combinations of surfactant with PLV improved oxygenation, Cdyn and survival, but none was clearly superior to the others.

Cocaine does not alter cardiac glycogen content at rest or during exercise.

Cocaine is a potent sympathomimetic drug, and has been implicated as a causative factor in cardiac seizures. However, little is known about the effect of the drug on myocardial substrate utilization. In the present study, rats were injected intravenously with saline solution or one of three doses of cocaine-HCl (1.25, 5.0, 10.0 mg/kg) and subsequently rested or exercised (22 m/min at 15% grade) for 20 minutes. Hearts were removed and frozen within 30 seconds after the injection of anesthetic and within 10 seconds after opening the thoracic cavity. The mean values for resting glycogen content ranged from 24.9 to 27.0 mumol/g, and for glucose-6-phosphate, from 0.27 to 0.30 mumol/g across groups. These values were unaffected by cocaine or exercise. We conclude, based on the conditions of this study, that cocaine has no direct or indirect effect on glycogen storage of the myocardium at rest or during exercise.

Effects of cocaine, exercise, and resting conditions on plasma corticosterone and catecholamine concentrations in the rat.

Cocaine and exercise are both known as stressors, but little is known about the combined effects of these two treatments. In this study, rats under the influence of cocaine (12.5 mg/kg, intraperitoneally [IP]) or saline were exposed to a variety of resting conditions, as well as exercise (running, 26 m/min, 10% grade, for 30 minutes), to evaluate the amount of stress imposed by these conditions as determined by the changes in the plasma concentrations of corticosterone (C) and catecholamines (norepinephrine [NE], epinephrine [E], dopamine [DA]). After injection of saline, resting near the operating treadmill for 30 minutes caused the concentration of C to increase from 0.07 +/- 0.03 to 0.30 +/- 0.05 microgram/mL (P less than .05), compared to the increase to only 0.15 +/- 0.04 micrograms/mL after resting in a cage. This increase due to proximity to the treadmill subsided after 50 minutes. After cocaine, the 30-minute resting values were 0.70 +/- 0.15 (treadmill) and 0.55 +/- 0.13 (cage) (P less than .05), and did not subside after 50 minutes. Cocaine also increased levels of E, NE, and DA above those in saline under all rest conditions. With exercise, the value for C in saline increased to 0.61 +/- 0.18, but, in cocaine, the value went to 0.93 +/- 0.05 (P less than .05). The concentrations of E (946 +/- 74 v 603 +/- 101 pg/mL, cocaine v saline) and NE (1,027 +/- 102 v 440 +/- 153, cocaine v saline) during exercise also were exaggerated by cocaine treatment (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cocaine on plasma catecholamine and muscle glycogen concentrations during exercise in the rat.

This study was designed to test the hypothesis that cocaine (C) alters the normal physiological responses to exercise. Male rats were injected with saline (S) or C (12.5 mg/kg) either intravenously (iv) or intraperitoneally (ip). After injection the animals were allowed to rest for 30 min or were run on the treadmill (26 m/min, 10% grade). At rest plasma epinephrine values were 245 +/- 24 pg/ml in the S group and 411 +/- 43 (ip) and 612 +/- 41 (iv) pg/ml in the C groups (P less than 0.05 between S and C). During exercise plasma epinephrine levels were 615 +/- 32 pg/ml in S and 1,316 +/- 58 (ip) and 1,208 +/- 37 (iv) pg/ml in the C groups (P less than 0.05 between S and C). Similar results were obtained for norepinephrine. Glycogen content in the white vastus lateralis muscle was reduced to 31 +/- 2 mumol/g in S after exercise, but after C and exercise the values were 12 +/- 4 (ip) and 16 +/- 3 (iv) mumol/g (P less than 0.05 between S and C). There was no effect of the drug on this parameter at rest. Blood lactate rose to 4.8 +/- 1.0 (ip) and 5.8 +/- 1.3 (iv) mM in the C groups but to only 3.0 +/- 0.2 in the S group after exercise (P less than 0.05 between S and C). These results show that C and exercise combined exert a more dramatic effect on plasma catecholamine, muscle glycogen, and blood lactate concentrations than do C and exercise alone. They provide further insight into explaining the adverse effects of C on exercise endurance observed previously (Bracken et al., J. Appl. Physiol. 66: 377-383, 1989).

Cocaine and exercise: alpha-1 receptor blockade does not alter muscle glycogenolysis or blood lactacidosis.

In our previous work, we routinely observed that a combined cocaine-exercise challenge results in an abnormally rapid muscle glycogen depletion and excessive blood lactacidosis. These phenomena occur simultaneously with a rapid rise in norepinephrine and in the absence of any rise in epinephrine. We postulated that norepinephrine may cause vasoconstriction of the muscle vasculature through activation of alpha-1 receptors during cocaine-exercise, thus inducing hypoxia and a concomitant rise in glycogenolysis and lactate accumulation. To test this hypothesis, rats were pretreated with the selective alpha-1-receptor antagonist prazosin (P) (0.1 mg/kg iv) or saline (S). Ten minutes later, the animals were treated with cocaine (-C) (5 mg/kg iv) or saline (-S) and run for 4 or 15 min at 22 m/min at 10% grade. In the S-S group, glycogen content of the white vastus lateralis muscle was unaffected by exercise at both time intervals, whereas in S-C rats glycogen was reduced by 47%. This effect of cocaine-exercise challenge was not attenuated by P. Similarly, blood lactate concentration in S-C rats was threefold higher than that of S-S after exercise, a response also not altered by pretreatment with P. On the basis of these observations, we conclude that the excessive glycogenolysis and lactacidosis observed during cocaine-exercise challenge is not the result of vasoconstriction secondary to norepinephrine activation of alpha-1 receptors.

Cocaine alters myosin isoform expression in the rat soleus.

The purpose of this study was to determine whether chronic cocaine administration alters the expression of myosin isoforms in the rat soleus. Forty-five adult Sprague-Dawley rats were divided into three groups: chronic cocaine (n = 15), 12.5 mg/kg cocaine-HCl injected intraperitoneally twice daily for 14 days and one injection of cocaine (12.5 mg/kg ip) on day 15; acute cocaine (n = 15), saline injections twice daily for 14 days and one injection of cocaine (12.5 mg/kg ip) on day 15; and chronic saline (n = 15), saline injections twice daily for 14 days and one saline injection on day 15. Myosin isoform content of the soleus (native and heavy chains) was identified by electrophoresis. The solei samples from the chronic saline and acute cocaine animals contained slow myosin only. However, solei samples from the chronic cocaine group contained slow myosin and two to three other myosin isoforms and the associated heavy chains IIa and IIx. Therefore, chronic cocaine administration causes in the rat soleus a shift in myosin expression from slow isoforms to fast isoforms.

Effects of glucose infusion in exercising rats.

To determine whether feedforward control of liver glycogenolysis during exercise is subject to negative feedback by elevated blood glucose, glucose was infused into exercising rats at a rate that elevated blood glucose greater than 10 mM. Liver glycogen content decreased 22.4 mg/g in saline-infused rats compared with 13.6 mg/g in glucose-infused rats during the first 40 min of treadmill running (21 m/min, 15% grade). Liver adenosine 3',5'-cyclic monophosphate (cAMP) concentration was significantly lower in the glucose-infused rats during the exercise bout. The concentration of hepatic fructose 2,6-bisphosphate remained elevated throughout the exercise bout in glucose-infused rats but decreased markedly in saline-infused rats. Plasma insulin concentration was higher and plasma glucagon concentration lower in glucose-infused rats than in saline-infused rats during exercise. Early in exercise, liver glycogenolysis proceeds in the glucose-infused rats despite the fact that glucose and insulin concentrations are markedly elevated and liver cAMP is unchanged from resting values. These observations suggest the existence of a cAMP-independent feedforward system for activation of liver glycogenolysis that can override classical negative feedback mechanisms during exercise.

Cocaine and exercise: physiological responses of cocaine-conditioned rats.

To compare the physiological response to a cocaine-exercise challenge in cocaine-conditioned animals with that of acute-cocaine animals, rats were injected i.p. with either cocaine (20 mg.kg-1) or saline, twice daily for 14 consecutive days. On the 15th day (test day) cocaine-conditioned rats received an i.v. injection of cocaine (5 mg.kg-1) (chronic group). One-half of the chronic saline rats also received the cocaine injection (acute group), while the other half received saline (saline group). Immediately after injection, all rats were either rested or exercised (22 m.min-1, 10% grade) for 30 min. For most parameters there was no difference between the responses of the chronic and acute cocaine groups at rest or to the cocaine-exercise challenge. During exercise, both cocaine groups had similarly higher lactate values than the saline animals (P < 0.05). Both groups had similarly greater reductions in glycogen content of the white and red vastus muscles than occurred in the saline group; and both groups had similar increases in corticosterone. In contrast, cocaine-conditioned animals had a greater rise in norepinephrine (P < 0.059) and epinephrine (P < 0.001) in response to cocaine-exercise than did the acute group. The mechanism responsible for the exaggerated catecholamine response in the chronic cocaine animals is unknown.

A prediction equation for estimating body fat percentage using readily accessible measures: a multivariate study of 200 adult women.

PURPOSE: This study was conducted to develop a regression equation that accurately estimates body fat percentage using relatively easy and inexpensive methods that do not require women to remove clothing. DESIGN: A cross-sectional design was employed. SETTING: All data were collected at the University. SUBJECTS: Subjects were 200 white women ages 20 to 65 years. The sample was equally distributed across four age groups, 20-29, 30-39, 40-49, and 50-65, and within each age group, one-third of the women were lean, one-third were of average weight, and one-third were obese. MEASURES: Subjects were hydrostatically weighed and participated in a variety of anthropometric and lifestyle assessments, including skinfolds, circumferences, and questionnaire responses. RESULTS: The full regression model included six measures: hip circumference, triceps skinfold (observed and quadratic), age (quadratic), self-reported physical activity, and calf skinfold (quadratic). This equation accounted for 81% of the variance in body weight measured by hydrostatic weighing (SEE = 3.5%). A simpler, five-variable equation was also formed that did not include the calf skinfold assessment (R2 = .800, SEE = 3.6%). CONCLUSIONS: The prediction equations in this study afford accurate and relatively easy and inexpensive means of estimating body fat percentage in a wide range of white women without having them remove their clothing.

Pediatric oncology nursing in cooperative group clinical trials comes of age.

OBJECTIVES: To provide a review of the nursing committees in both the Children's Cancer Group and the Pediatric Oncology Group and discuss intergroup nursing research collaboration in preparation for the merger of these cooperative clinical trials groups. DATA SOURCES: Review articles, reports, and newsletters from cooperative clinical trials groups. CONCLUSIONS: Nurses have established a vital presence in the pediatric cancer cooperative groups over the past 20 years through education, clinical practice, and collaborative research. IMPLICATIONS FOR NURSING PRACTICE: With the unification of the pediatric cooperative groups into the single Children's Oncology Group, the time is uniquely right to build a program of nursing research allied with pediatric oncology cooperative group clinical trials.

Radiation therapy in childhood cancer.

OBJECTIVES: To review treatment-related issues and acute and late side effects of radiation therapy for the treatment of childhood malignancies. DATA SOURCES: Research and review articles, oncology textbooks, and clinical experience. CONCLUSIONS: Radiation therapy is a key component in the treatment of childhood malignancies. Children receiving radiation have special nursing care needs that are dependent on growth and developmental issues. IMPLICATIONS FOR NURSING PRACTICE: Nurses play an important role in the education of families and children receiving radiation therapy. In addition, nurses are key in the management of acute and late toxicities from childhood radiation therapy.

Immersion treatment of childhood and adolescent obesity: the first review of a promising intervention.

Obese children have attended weight loss camps and residential programmes for more than 40 years. This paper provides the first systematic review of the effects of those programmes. Twenty-two studies met inclusion criteria (targeted and assessed change in weight status, minimal stay of 10 days and nights). Similar components across programmes included controlled diet, activities, nutrition education, and therapy and/or education regarding behaviour change. Participants lost substantial amounts of weight in all 22 studies, as measured by reductions in per cent-overweight during intervention. Eleven programmes included long-term follow-up evaluations. Compared with results highlighted in a recent meta-analysis of out-patient treatments, these immersion programmes produced an average of 191% greater reductions in per cent-overweight at post-treatment and 130% greater reduction at follow-up. Furthermore, mean attrition rates were much lower when compared with standard out-patient treatment. Inclusion of a cognitive-behavioural therapy (CBT) component seemed especially promising; follow-up evaluations showed decreased per cent-overweight at follow-up by an average of 30% for CBT immersion programmes vs. 9% for programmes without CBT. Explanations for the potentially greater impact of immersion relative to out-patient treatments are presented, including possibly differential effects on self-efficacy for both children and their parents.

A comparison of bispectral index and entropy monitoring, in patients undergoing embolization of cerebral artery aneurysms after subarachnoid haemorrhage.

BACKGROUND: Processed EEG monitoring of anaesthetic depth could be useful in patients receiving general anaesthesia following subarachnoid haemorrhage. We conducted an observational study comparing performance characteristics of bispectral index (BIS) and entropy monitoring systems in these patients. METHODS: Thirty-one patients of the World Federation of Neurosurgeons grades 1 and 2, undergoing embolization of cerebral artery aneurysms following acute subarachnoid haemorrhage, were recruited to have both BIS and entropy monitoring during general anaesthesia. BIS and entropy indices were matched to clinical indicators of anaesthetic depth. Anaesthetists were blinded to the anaesthetic depth monitoring indices. Analysis of data from monitoring devices allowed calculation of prediction probability (P(K)) constants, and receiver operating characteristic (ROC) analysis to be performed. RESULTS: BIS and entropy [response entropy (RE), state entropy (SE)] performed well in their ability to show concordance with clinically observed anaesthetic depth. P(K) values were generally high (BIS 0.966-0.784, RE 0.934-0.663, SE 0.857-0.701) for both forms of monitoring. ROC curve analysis shows a high sensitivity and specificity for all monitoring indices when used to detect the presence or absence of eyelash reflex. Area under curve for BIS, RE and SE to detect the absence or presence of eyelash reflex was 0.932, 0.888 and 0.887, respectively. RE provides earlier warning of return of eyelash reflex than BIS. CONCLUSION: BIS and entropy monitoring perform well in patients who receive general anaesthesia after good grade subarachnoid haemorrhage.

Effect of partial liquid ventilation and nebulized perfluorocarbon on CT lung density distribution: randomized controlled study of experimental lung injury.

BACKGROUND: Perfluorocarbon (PFC) liquid can improve gas exchange in acute lung injury. How PFC aerosol is distributed in the lung is unknown. METHODS: We induced lung injury in rabbits with saline lavage, followed by mechanical ventilation in the supine position. The animals were divided into three groups: a control group, a group treated with partial liquid ventilation and a group given nebulized perfluorocarbon (PF 5080). We made CT image slices of the excised lungs. In the apical, middle and caudal slices we defined three regions of interest, from anterior to posterior, and noted the mean attenuation of each area. We also studied two rabbits which had not received lung injury or mechanical ventilation. RESULTS: Group means were different between the normal rabbits and all three study groups. There was a difference between the control and partial liquid ventilation groups, and between the partial liquid ventilation and nebulized groups, but no difference between the nebulized and control groups. Within each treatment group, there was no regional difference in the distribution of density. CONCLUSIONS: PF 5080 is not deposited in large amounts by aerosol. Less PFC was found in the lungs after partial liquid ventilation than expected. Within treatment groups, lung densities indicate less gravitational and regional differences than found in other studies.

Septic shock from the administration of a bacterially contaminated platelet transfusion.

We report the case of a 6-year-old boy who began to have fever and hypotension during the administration of a platelet transfusion. Subsequent investigation revealed the etiology to be bacterial contamination of the platelet product. Seratia marcescens was cultured from both the patient's blood and the platelet product. When fever and/or cardiorespiratory problems develop during the administration of blood products, possible bacterial contamination of the product must be considered so that appropriate therapy can be instituted. We discuss the etiology, possible preventive strategies, and the treatment of this problem.