Biomedical subjects

S G Owen

Publications and source records attributed to S G Owen.

16 recordsLinked to original sources

PubMed1999

The 'primeless pump': a novel technique for intraoperative blood conservation.

PURPOSE: Hemodilution during cardiopulmonary bypass may lead to anemia requiring intraoperative transfusions. Prime removal from the cardiopulmonary bypass circuit was used to limit dilution and intraoperative transfusions. METHODS: The technique of prime removal consists of arterial and then venous side evacuation of crystalloid prior to cardiopulmonary bypass. The effectiveness of this technique, to maintain a higher hematocrit and reduce intraoperative transfusions, was studied prospectively in two consecutive groups of patients undergoing coronary revascularization (controls versus primeless). RESULTS: Intraoperative hematocrits were significantly higher (P < 0.0001) and transfusions lower (4%) in the primeless versus the control group (19%) (P = 0.003). Prime removal is of particular benefit in anemic (hematocrit < or = 35%) and/or small patients (body surface area < or = 2 m2). CONCLUSION: The technique of prime removal is simple, safe and cost-effective, reducing intraoperative transfusions, especially in small and/or anemic patients. It could be part of blood conservation strategies in most adult cardiac operations.

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PubMed1995

Tranexamic acid significantly reduces blood loss associated with coronary revascularization.

Four hundred fifteen patients undergoing coronary revascularization over a 12-month period were divided into two groups: 209 controls in the first 6 months received no tranexamic acid (TA) before cardiopulmonary bypass and 206 patients in the second 6 months received TA as a hemostatic agent. The demographics and the surgical techniques used were similar in the two groups. With TA there was a significant decrease in blood loss postoperatively, from 1,114.1 mL in the controls to 803.7 mL in those given TA (p < 0.001); in red blood cell use, from 1.7 units/patient in the controls to 0.69 units/patient in those given TA (p < 0.001); in fresh frozen plasma requirements, from 0.23 units/patient in the controls to 0.024 units/patient in those given TA (p < 0.01); and in platelet transfusion, from 1.06 units/patient in the controls to 0.30 units/patients in those given TA (p < 0.01). The percentages of patients not receiving any blood products were 65% in those given TA versus 49% in the controls (p < 0.01). There was no significant difference between the two groups in the incidence of perioperative myocardial infarction, cerebrovascular accidents, pulmonary embolism, or venous thrombosis to clearly suggest hypercoagulability. In this study, TA profoundly affected the coagulopathy associated with bypass in patients undergoing coronary revascularization. It significantly reduced blood loss and blood product transfusions. Any potential increased thrombotic complications could not be clearly demonstrated in this study, but should not be ignored.

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PubMed1994

Fast-track recovery of the coronary bypass patient.

A new approach termed "fast-track recovery" ws undertaken at both the Baystate Medical Center and Hartford Hospital. The fast-track protocol involves the following principles: (1) preoperative education; (2) early extubation; (3) methylprednisolone sodium succinate before bypass followed by dexamethasone for 24 hours postoperatively; (4) prophylactic digitalization, metoclopramide HCl, docusate sodium, and ranitidine HCl; (5) accelerated rehabilitation; (6) early discharge; (7) a dedicated fast-track coordinator to perform both daily telephone contact and a 1-week postoperative examination; and (8) a routine 1-month postoperative visit with a PA or MD. To evaluate the effects of this approach on patient care, a retrospective 1-year analysis was undertaken in both institutions with all coronary artery bypass grafting patients compared in a consecutive manner before the origin of the fast-track protocol and subsequent to its beginning. There were 280 patients in the fast-track and 282 in the non-fast-track group. The two groups were not significantly different except inexplicably there was a lower ejection fraction in the fast-track group and a longer cross-clamp time. Postoperatively, the mean time to extubation decreased from 22.1 to 15.4 hours, and peak weight gain decreased from 2.8 to 1.6 kg from the non-fast-track to the fast-track group (p < 0.01). This was accompanied by significant (p < 0.001) decreases in intensive care unit duration from 2.4 to 1.9 days and in postoperative length of stay from 8.3 to 6.8 days from the non-fast-track to the fast-track group. There was no increase in morbidity or mortality associated with the fast-track protocol either early or late. Thirty-day hospital readmission was not significantly different between the two groups. Fast-track methodology is effective, and we routinely employ this approach for all patients undergoing cardiopulmonary bypass.

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PubMed1994

Disappearance kinetics of solutes from synovial fluid after intra-articular injection.

1. Five rheumatoid patients with a knee joint effusion participated in the study. An aqueous solution (0.1 to 0.2 ml) containing paracetamol, salicylate, diclofenac and [125I]-albumin was injected into a given joint to yield target concentrations of approximately 20 micrograms ml-1 for diclofenac, salicylate and paracetamol and 10(8) counts ml-1 for [125I]-albumin. 2. Paracetamol, salicylate and diclofenac were analysed in synovial fluid by h.p.l.c. [125I]-albumin was analysed using gamma counting. 3. The clearances (+/- s.d.) obtained for the solutes were [125I]-albumin (0.0053 +/- 0.0019 l h-1), diclofenac (0.0096 +/- 0.0061 l h-1), salicylate (0.024 +/- 0.022 l h-1) and paracetamol (0.055 +/- 0.041 l h-1). The corresponding fractions unbound of these solutes in synovial fluid were 0.0, < or = 0.01, 0.34 +/- 0.09 and 0.85 +/- 0.10, respectively. 4. Diffusion of unbound solute through the synovium is estimated to account for (+/- s.d.) 0.52 +/- 0.08, 0.87 +/- 0.06 and 0.99 +/- 0.01 of the total clearance of diclofenac, salicylate and paracetamol from the joint space, respectively. The remaining proportion of clearance is accounted for by efflux of solute bound to albumin. 5. An expression for the ratio of synovial fluid to total plasma concentrations after systemic administration was developed to include both diffusion of unbound solute and albumin flux. Most solutes appear to satisfy the conditions in which this expression reduces to the limiting case where the unbound concentration of the solute is identical in the synovial fluid and plasma under steady state conditions.

Acetaminophen↗

PubMed1994

Emergency cardiopulmonary bypass in the cardiac surgical unit can be a lifesaving measure in postoperative cardiac arrest.

BACKGROUND: Postoperative cardiac arrest that is not responsive to conventional resuscitation is uniformly fatal. Sixteen patients who experienced postoperative ventricular fibrillation (VF) and arrest over a 6-year period and did not respond to open chest resuscitation were placed on an emergency basis on cardiopulmonary bypass (CPB) in the cardiac surgical intensive care unit (CSICU). METHODS AND RESULTS: Data were reviewed by retrospective analysis. Nine of the 16 patients (56.3%) survived, and they spent a mean of 9 +/- 2.8 days in the CSICU and a mean of 17 +/- 4.6 days in the hospital. They all are alive 1 month to 5 1/2 years later. The mean interval between VF/arrest and CPB in the CSICU was 50 +/- 6.7 minutes (range, 25 to 83 minutes) for survivors and 51 +/- 6.1 minutes (35 to 83 minutes) for nonsurvivors (P = .98). The duration of CPB in the CSICU was 111 +/- 16.0 minutes (range, 55 to 189 minutes) for survivors and 167 +/- 20.7 minutes (range, 80 to 232 minutes) for nonsurvivors (P = .05). There were no apparent differences between survivors and nonsurvivors in age, history of arrhythmias, use of antiarrhythmics, congestive heart failure, recent myocardial infarction, ejection fraction, preoperative intra-aortic balloon pump, urgency, or type of operation. Surgical variables and postoperative medications and electrolytes (after the primary procedure) were similar. The use of cardioplegic arrest during CPB in the CSICU was higher among survivors (3 of 9) compared with 0 of 7 for nonsurvivors (P = .21). There was no mediastinitis and only two minor soft tissue infections among survivors. CONCLUSIONS: The use of CPB in the CSICU can achieve significant survival in patients who have otherwise irreversible cardiac arrest and/or VF after surgery; the incidence of infection in patients undergoing CPB in the CSICU is very low; and the use of warm cardioplegic arrest may enhance the changes of survival in this type of patient.

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PubMed1989

Salicylate pharmacokinetics in patients with rheumatoid arthritis.

1. The pharmacokinetics of salicylic acid (SA) and its major metabolite salicyluric acid (SU) were studied in nine patients with rheumatoid arthritis following a 900 mg oral dose of acetylsalicylic acid and during 6 weeks of chronic administration of enteric coated aspirin (3,900 mg day). Response to therapy was also monitored. 2. The various pharmacokinetic parameters determined in the study were similar to those observed in other single dose salicylate studies amongst healthy volunteers but were not predictive of salicylate concentration in the chronic dose study. 3. Plasma concentrations of SA (total and unbound) were found to decline significantly over the 6 weeks and plasma SU concentrations increased. 4. During the chronic dosing study, there was a significant increase in the Vmax (total and unbound) for the formation of SU, whilst the Km and SU clearance remained constant. Also, the elimination rate constant (k) for salicylate was not significantly affected. 5. Therapeutic response to salicylate therapy was not significantly affected by the decline in SA concentrations.

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PubMed1987

Rapid high-performance liquid chromatographic assay for the simultaneous analysis of non-steroidal anti-inflammatory drugs in plasma.

A high-performance liquid chromatographic assay has been developed for the determination of a number of non-steroidal anti-inflammatory drugs in plasma. The samples were prepared by adding acetonitrile and perchloric acid to 200 microliter of plasma. Diclofenac, fenoprofen, ketoprofen, naproxen, phenylbutazone, piroxicam and sulindac were quantified in the supernatant produced using a mobile phase of phosphoric acid 0.03% (pH 2.5)-acetonitrile and a detecting wavelength of 254 nm. The reproducibility, linearity, precision and specificity of the assay were determined and found to be satisfactory. Alteration of the detection wavelength to 229 nm also permitted accurate determination of ibuprofen concentration in plasma. While reduction of the organic solvent content of the mobile phase and alteration of wavelength to 313 nm produced a system capable of quantifying salicylate and its metabolites in plasma and by further reducing the detecting wavelength to 237 nm, aspirin also was quantifiable. These methods have been applied in a cross-sectional study of medication compliance among rheumatoid arthritis patients treated with non-steroidal anti-inflammatory drugs.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1986

Functional capacity and treatment data from a community based study of patients with rheumatoid arthritis.

A community based study of rheumatoid arthritis was undertaken to determine patient characteristics and the patterns of treatment. Three hundred and eighty subjects were visited in their homes throughout Tasmania (pop. 430 000) by a research team. The median age of the sample was 60 years (interquartile range (IR) 49-69), with a female predominance of 2.65 to 1. The average onset age was 41 years (IR 30-53). Prescribing data indicated that polypharmacy was not common in the community, and that the use of slow acting antirheumatic drugs (SAARDs) and oral corticosteroids was not widespread. At the time of the study 26% of subjects were assayed fully functional--class I of the American Rheumatism Association's (ARA) functional classifications. The functional capacity data provided evidence that the spectrum of rheumatoid arthritis found in the community differed from that found in specialist rheumatology clinics.

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PubMed1985

Community Surveillance Study--perceived response of rheumatoid arthritis patients to NSAIDs.

The perceived effectiveness of nonsteroidal anti-inflammatory drugs was studied in a community population (n=380). The population characteristics of a sample were similar to previous studies. Most patients were on a single NSAID. Rheumatoid arthritis (RA) was found to have a significant impact in terms of disability and lifestyle. Active inflammation was the main incentive to comply with therapy. However, the patients perceptions about the efficacy of the medication, their attitude towards the medication and their motivations for taking it, also affected compliance. A decreased effectiveness of therapy may also be due in part to tolerance to some medications and some evidence of the induction of salicylate metabolism has been reported. Considerable variation in the patients' perception of other forms of therapy for RA were also observed.

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PubMed1985

Determinants of compliance in rheumatoid arthritic patients assessed in their home environment.

Patient compliance with prescriber's medication instructions was investigated in 178 rheumatoid arthritis patients treated in community practice. The compliance rate in the sample subjects was estimated to be 63.5%. Disease activity, measured objectively with erythrocyte sedimentation rate (ESR) and subjectively by duration of morning stiffness, was a major incentive for adherence to the treatment regimen. Among subjects with active disease (ESR greater than 20 mm in 1 h), the rate of compliance was 73.8%, but this fell to 52.7% among those with a normal ESR (i.e. ESR less than or equal to 20 mm in 1 h). The motivations and perceptions of the subjects concerning their drug therapy also affected compliance. Compliance was however less dependent on perceptions when active inflammation was present.

Administration, Oral↗

PubMed1976

International coordination of biomedical research.

Recent efforts at international coordination in biomedical research have taken place at two levels. At the level of the working clinician and scientist, European regionalism has become increasingly manifest in such organizations as the European Society for Clinical Investigation, the European Organization for Research into the Treatment of Cancer, the European Molecular Biology Organization and many others. These have developed largely, though not entirely, independently of government funding. At the level of science policy, i.e. of bodies supporting biomedical research mainly from public funds, the major developments have been the Comité de la Recherche Médicale of the European Community and the much wider association of European Medical Research Councils, based on the whole of Western Europe; in October 1975 the latter group became incorporated into the new European Science Foundation as the first Standing Committee of that body. Wider, interregional, cooperation presents greater problems, though there have been some modest successes, and the multinational drive on research into six of the major health problems of the Third World now being proposed by WHO holds further promise for the future.

Europe↗

PubMed1970