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At least 91 records · Page 5Linked to original sources
PubMed1997

A comparison of pressure- and volume-controlled ventilation at different inspiratory to expiratory ratios.

BACKGROUND: Inverse ratio ventilation (IRV) is frequently used in severe acute respiratory failure. IRV may lead to intrinsic positive end-expiratory pressure (PEEP) and is thought to improve oxygenation and to have advantageous effects on lung mechanics. Published data to support the use of IRV are scarce. This animal study compares external PEEP with intrinsic PEEP in pressure- and volume-controlled ventilation. METHODS: Fifteen pigs were randomly treated with 1. volume-controlled PEEP ventilation (I:E ratio 1:2) (VCV PEEP), 2. volume-controlled ventilation (I:E ratio 4:1) (VCIRV) and 3. pressure-controlled ventilation (I:E ratio 4:1) (PCIRV). Baseline measurements were performed using volume-controlled ventilation (I:E ratio 1:2) (VCV ZEEP). Lung mechanics, haemodynamics and gas exchange were measured by standard methods and functional residual capacity (FRC) by the sulphur hexafluoride technique. RESULTS: In comparison to VCV PEEP, PCIRV resulted in reduced peak airway pressure (32 +/- 3 vs. 27 +/- 6 cm H2O, P < 0.001) and increased mean airway pressure (14 +/- 2 vs. 22 +/- 5 cm H2O, P < 0.001). FRC was 942 +/- 264 ml in VCV PEEP and 1024 +/- 390 ml in PCIRV (n.s.). Oxygen delivery was lower in PCIRV (458 +/- 193 vs. 346 +/- 150 ml/min, P < 0.05). Physiologic dead space was 14 +/- 4% in PCIRV and 20 +/- 6% in VCV PEEP and VCIRV (P < 0.005). CONCLUSIONS: Inverse ratio ventilation did not result in improved FRC in comparison to conventional volume-controlled PEEP ventilation. PCIRV allows for a reduction in minute ventilation but the increase in mean airway pressure compromises circulation.

Airway Resistance↗
PubMed2005

Oversizing pulmonary homograft conduits does not significantly decrease allograft failure in children.

OBJECTIVE: Placement of oversized pulmonary ventricle-pulmonary artery conduits is routinely performed to decrease conduit failure in children. However, this practice has recently been challenged as somatic outgrowth may not be the main determinant of allograft failure in children. Our objective was to determine whether placement of oversized homografts for extracardiac pulmonary ventricle (PV) outflow tract reconstruction improves longevity in young children. METHODS: We reviewed 102 consecutive PV-PA conduits inserted in 70 patients less than 18 years between 1984 and 2003. Conduits placed in an anatomic position (n=23) as part of a Ross operation, were excluded. Conduits were initially stratified into two age groups: Group 1, those placed in patients 10 years. Normalization of conduit size to patient's body surface area at the time of insertion (z-value) was then performed to divide the conduits into oversized (O/S) and non-oversized (NO/S) groups. Determinants of conduit failure and allograft longevity were then compared between groups. RESULTS: Seventy-nine extracardiac conduits were placed, and 57 of these were in patients under 10 years of age. The majority had a diagnosis of tetralogy of Fallot (n=38), truncus arteriosus (n=19), pulmonary atresia with ventricular septal defect (n=12), or D-TGA with pulmonary stenosis and ventricular septal defect (n=7). Thirty-seven conduits were oversized (O/S) based on z-value, and 42 were non-oversized (NO/S), and the mean age at initial homograft placement was 7.0+/-7.5 years. Overall, oversizing conferred no significant advantage with respect to actuarial freedom from homograft replacement at 1, 5, or 10 years (96, 79, and 21%, O/S vs 93, 60, and 24%, NO/S), P=0.44. Oversizing was more frequent in Group 1 than Group 2 (53 vs 32%), and conduit failure was also more frequent with 49% requiring reoperation during the study period vs 38% in Group 2. In the subset of patients <or=10 years, both homograft explantation rate (50% O/S vs 48% NO/S) and median interval to conduit failure were similar between the O/S and NO/S patients (7.1 vs 4.8 years), P=0.340. Risk factors for conduit failure identified in multivariable regression analysis included the presence of pulmonary artery branch stenosis, lack of previous definitive repair, a diagnosis of pulmonary atresia, the need for percutaneous intervention. CONCLUSIONS: There is no significant benefit to placement of an oversized PV-PA homograft in this series of patients from a single institution. Even in young patients with rapid somatic growth, normalizing extracardiac allografts to BSA provides excellent conduit longevity and outcomes.

Adolescent↗
PubMed2003

Ecotoxicological responses of the mayfly Baetis tricaudatus to dietary and waterborne cadmium: implications for toxicity testing.

Trace metals readily accumulated by stream periphyton may enter aquatic food chains through grazer ingestion. Hence, experiments were conducted to determine the ecotoxicological responses of the grazing mayfly Baetis tricaudatus to dietary cadmium. Short-term feeding experiments indicated that B. tricaudatus nymphs did not initially avoid grazing on cadmium-contaminated diatom mats. During a partial life-cycle experiment, 4 and 10 microg/g of dietary cadmium significantly inhibited grazing, whereas 10 microg/g significantly inhibited growth. Feeding inhibition was the likely mechanism that inhibited growth (i.e., through reduced energy intake). Conversely, when exposed to waterborne cadmium using lethal toxicity test procedures, B. tricaudatus nymphs were relatively tolerant (96-h median lethal concentration, 1,611 microg/L). Thus, sublethal responses to dietary exposure appeared to be more sensitive than lethal responses to waterborne exposure. Because adult mayfly fecundity is a function of nymph size at emergence, dietary cadmium exposure could increase the extinction probability within mayfly populations. The present study highlights the importance of dietary exposure routes in determining the ecotoxicological responses of an organism to a contaminant. Furthermore, the findings emphasize the advantage of evaluating a combination of ecologically relevant, lethal and sublethal endpoints in laboratory methods used to generate data for ecological risk assessment and regulation.

Animals↗
PubMed1992

A survey of the use of blood and blood components among South African anaesthetists working in teaching hospitals.

A survey of the peri-operative policies for blood and blood component therapy was carried out among anaesthetists in the nine South African teaching hospitals. All anaesthetists completed the questionnaire, without recourse to books or discussion. The survey revealed a possible over-utilisation of blood and blood components in the peri-operative period. There were significant deficiencies in the pre-operative assessment of blood and platelet requirements and the specific indications for platelet, fresh frozen plasma and blood transfusions. A significant number of respondents exhibited poor knowledge of the potential dangers and expense that the use of blood and blood components entails. Educational effort was perceived to be the main method of rationalising the anaesthetist's usage of blood and blood components.

Anesthesiology↗
PubMed1979

The effect of aspirin on the fibrinolytic activity of gastric juice.

Fibrinolytic activity in the gastric juice of normal subjects has been studied by a double-blind cross-over technique comparing the effect of placebo and pentagastrin against aspirin and pentagastrin. Aspirin effectively produced a gastritis and pure fibrinolytic activity was detected in the gastric juice, but the number of samples showing pure fibrinolytic activity did not differ between the two groups. In both the placebo and the aspirin groups the presence of a protease active at neutral pH and capable of dissolving fibrin is confirmed. Aspirin is unlikely to cause gastric bleeding by increasing local fibrinolytic activity within the stomach. The model, so constructed, is not sensitive enough to be of value in investigating further the role of gastric fibrinolytic activity in gastric haemorrhage.

Adult↗
PubMedDate not supplied

[Posture-dependent changes in lung function and cardiovascular parameters in pregnant females at delivery date].

The objective of the investigation was to clarify whether, from the pulmonary or cardiological viewpoint, preference should be given to delivery in the sitting or lying position. For this purpose a spirometry was carried out in 28 pregnant women, average age 26 (19 to 35) and 15 control persons, average age 30 (20 to 41). In addition, the cardiac output of 12 pregnant women at the final date of confinement as well as of 10 persons of corresponding age for comparison purposes was determined by means of the CO2 rebreathing method. In none of the women investigated had labour set in. There were no significant differences of the VC, the IRV, the ERV and the FEV1 in the two groups examined, either in the lying or in the sitting position. Both in the sitting and in the lying position the arterial oxygen partial pressure of the pregnant women at rest was significantly above that of the control group. After stress both groups showed an increase of PaO2 and no longer differed significantly from one another. A difference in the PaCO2 depending on the position was not ascertainable in either group. However, the pregnant women had a significantly lower PaCO2 than the control group. The cardiac output of pregnant women did not differ significantly in the sitting position from those of the control group (4.7 +/- 1.3 and 5.3 +/- 1.5 1/min. respectively). Whereas the cardiac output of the comparison group rose in the lying position to 5.2 +/- 0.9 1/min, in the case of the pregnant women it dropped significantly (p less than 0.01) to 3.6 +/- 1.2 1/min. These findings show that a decision as to whether the delivery should take place in the sitting or lying position cannot be taken on the basis of parameters that analyse the lung function. The significant reduction of the cardiac output of those women lying on their back during labour, caused by the compression of the vena cava inferior and of the aorta by the uterus, indicates that the second stage of labor is better carried out in a position other than lying, e.g. the sitting position.

Adult↗
PubMed1986

The use of microcomputers for data management in a large epidemiological survey.

A data management system designed around microcomputers and commercial software packages was employed for a large epidemiological study. Management involved the tracking of subjects through several stages of the study and the generation of subject listings, personalized letters of invitation, daily worklists for the field teams, and a checklist for the laboratories. These processes were controlled using a continually updated subject data base which in final form provided the core of the management system for the collected data. Data management presented major problems because of the volume of data which were received from several sources over a period of months. A key feature to emerge was the importance of an accurate serial number on all items for which a check digit was employed. The system had a short development time and was found to be inexpensive and flexible and to cope easily with the demands made of it.

Computers↗
PubMed2005

Human immune response to a plague vaccine comprising recombinant F1 and V antigens.

The human immune response to a new recombinant plague vaccine, comprising recombinant F1 (rF1) and rV antigens, has been assessed during a phase 1 safety and immunogenicity trial in healthy volunteers. All the subjects produced specific immunoglobulin G (IgG) in serum after the priming dose, which peaked in value after the booster dose (day 21), with the exception of one individual in the lowest dose level group, who responded to rF1 only. Three subjects, found to have an anti-rV titer at screening, were excluded from the overall analysis. Human antibody functionality has been assessed by quantification of antibody competing for binding to rV in vitro and also by the transfer of protective immunity in human serum into the naive mouse. Human and macaque IgG competed for binding to rV in vitro with a mouse monoclonal antibody, previously shown to protect mice against challenge with plague, suggesting that this protective B-cell epitope on rV is conserved between these three species. Total IgG to rV in individuals and the titer of IgG competing for binding to rV correlated significantly at days 21 (r = 0.72; P < 0.001) and 28 (r = 0.82; P < 0.001). Passive transfer of protective immunity into mice also correlated significantly with total IgG titer to rF1 plus rV at days 21 (r(2) = 98.6%; P < 0.001) and 28 (r(2) = 76.8%; P < 0.03). However, no significant vaccination-related change in activation of peripheral blood mononuclear cells was detected at any time. Potential serological immune correlates of protection have been investigated, but no trends specific to vaccination could be detected in cellular markers.

Adult↗
PubMedDate not supplied

Intra-arterial prostacyclin compared to Praxilene in the management of severe lower limb ischaemia: a double blind trial.

The effectiveness of a 72 h. intra-arterial prostacyclin infusion has been compared to that of naftidrofuryl oxalate (Praxilene) in a double blind study of 29 patients with ischaemic rest pain in 30 legs. Long-term relief of symptoms was achieved in 14 legs (47%) and major limb amputation avoided in 18 (60%). No significant difference was demonstrated between the results of prostacyclin infusion and those of Praxilene.

Aged↗
PubMed1994

Esophageal motility in AIDS patients with symptomatic opportunistic infections of the esophagus.

OBJECTIVES: In patients with AIDS, esophageal symptoms are commonly due to opportunistic esophageal infection with Candida, cytomegalovirus (CMV), herpes simplex virus (HSV), and HIV. Despite apparently appropriate therapy against these pathogens, some patients continue to complain of dysphagia or odynophagia. This study was designed to determine whether such complaints were associated with a motility disorder of the esophagus. METHODS: Sixteen patients underwent esophagoscopy and biopsy followed by esophageal manometry, performed using a 5-channel water perfused system (Synectics Medical, Inc., Irving, Texas). All patients had odynophagia, and eight had dysphagia. RESULTS: Identified infections included: Candida (11), HSV and Candida (1), CMV (3), and a giant ulcer presumably caused by HIV (1); one patient also had lymphoma. Seven patients had normal esophageal motility, and in nine patients, a nonspecific motility disorder was found. After therapy, one of 10 patients had persistent odynophagia and dysphagia, and two had odynophagia only. At follow-up endoscopy, complete healing was demonstrated in six of eight patients with Candida. One of two patients with CMV and the patient with HSV also showed complete healing of the esophagus. Repeat esophageal motility studies were performed after therapy in 10 patients. Five had a persisting abnormality despite eradication of the pathogen (three Candida, one HSV, one CMV); in four, the previously identified motor abnormalities resolved after eradication of the infection (three Candida, one CMV). CONCLUSIONS: These findings suggest that a nonspecific motility disorder exists in AIDS patients with esophageal symptoms and may contribute to the persistence of symptoms despite appropriate therapy of esophageal opportunistic infections.

AIDS-Related Opportunistic Infections↗
PubMed1992

Serum myoglobin and creatine kinase enzymes in acute myocardial infarction treated with Anistreplase.

AIMS: To compare plasma myoglobin concentration and cardiac enzyme activity with electrocardiographic (ECG) changes in two groups of patients (reperfused and non-reperfused) participating in a placebo-controlled randomised double blind trial of treatment of myocardial infarction (MI) with intravenous thrombolytic therapy (Anistreplase). METHODS: Twenty two patients with confirmed MI obeying strict inclusion and exclusion criteria were studied. Plasma myoglobin was measured by radioimmunoassay and creatine kinase enzyme (CK and CKMB) by NAC activated and NAC activated/immunoinhibition methods respectively in all patients before and at frequent intervals after injection of Anistreplase or placebo. Patients were divided into reperfused (R) and non-reperfused (NR) groups on the basis of ECG criteria. Reperfusion was diagnosed if the measured ST segment elevation fell by greater than or equal to 50% at 2 hours post dosing. RESULTS: The time to peak (TTP) myoglobin was significantly less in the R group compared with the NR group but there was considerable overlap in the range of values. The area under the enzyme time curves (AUCs) and summed ST segment epsilon ST elevations were significantly smaller in the R compared with the NR group. CONCLUSIONS: Although TTP myoglobin results were significantly lower in the R group, TTP myoglobin will probably not be useful as an non-invasive indicator of reperfusion because of the overlap in values between the two groups. The significant reduction in the AUC and epsilon ST only in the R group suggests decreased infarct size. However, in this small preliminary study reperfusion did not occur more frequently with Anistreplase than without.

Adult↗
PubMed1996

Treatment principles in advanced non-small-cell lung cancer.

Non-small-cell lung cancer (NSCLC) accounts for more than three quarters of all lung tumours and is the leading cause of deaths due to cancer in Australia. More than half of the patients with NSCLC present with advanced disease. Radiation therapy has been the mainstay of active treatment for these patients. There is increasing evidence supporting the benefit of chemotherapy as an addition to radiation therapy in locally advanced non-metastatic disease. The use of cisplatin-based chemotherapy prior to radiation therapy would appear to be a new standard of care in patients with stage III B NSCLC. In advanced (metastic) disease, palliation of symptoms remains the major goal of current treatment programmes. This can be achieved with the best supportive care, radiotherapy, and, in selected patients, platinum-based chemotherapy. Clinical trials to test new treatments, with survival, quality of life and cost-benefit as endpoints, are essential. The present study discusses the current status of conventional and newer treatment methods in locally advanced and metastatic disease.

Antineoplastic Combined Chemotherapy Protocols↗