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Biomedical subjects

D E Roberts

Publications and source records attributed to D E Roberts.

At least 19 recordsLinked to original sources
PubMed1992

Policy for controlling pain after surgery: effect of sequential changes in management.

OBJECTIVE: To observe the effects of introducing an acute pain service to the general surgical wards of a large teaching hospital. DESIGN: A study in seven stages: (1) an audit of current hospital practice succeeded by the sequential introduction to the general surgical wards of (2) pain assessment charts; (3) an algorithm to allow more frequent use of intramuscular analgesia; (4) increased use of local anaesthetic techniques of wound infiltration and nerve blocks; (5) an information sheet for patients about postoperative pain; (6) the introduction of patient controlled analgesia; (7) a repeat audit of hospital practice. Data were collected on each patient 24 hours after operation. SETTING: University Hospital of Wales, which has both district general and tertiary referral functions. PATIENTS: 2035 patients over nine months from all surgical specialties (excluding cardiac) at the hospital. General surgical operations were studied in detail and separated into major, intermediate, and minor for data collection. MAIN OUTCOME MEASURES: A change in the median visual analogue pain scores 24 hours after surgery for pain during relaxation, pain on movement, and pain on deep inspiration at each stage of the study. RESULTS: There was a reduction in median visual analogue scores during the study. The median (95% confidence interval) scores for pain during relaxation decreased from 45 (34 to 53) in stage 1 to 16 (10 to 20) in stage 7 for major surgical procedures. Pain on movement decreased from 78 (66 to 80) to 46 (38 to 48), and pain on deep inspiration decreased from 64 (48 to 78) to 36 (31 to 38). The reductions in median scores for intermediate and minor operative procedures showed similar patterns. CONCLUSIONS: The introduction of an acute pain service to the general surgical wards led to considerable improvement in the level of postoperative pain as assessed by visual analogue scores. Simple techniques of regular pain assessment and the more frequent use of intramuscular analgesia as a result of using an algorithm were particularly effective.

Algorithms↗
PubMed1992

Value of postprocedural chest radiographs in the adult intensive care unit.

OBJECTIVE: To evaluate the necessity for postprocedural chest radiographs after catheterization of central veins, insertion of pulmonary artery catheters, and placement of endotracheal tubes. DESIGN: Prospective, controlled study. SETTING: Two academic tertiary adult ICUs. PATIENTS: Consecutive patients (n = 316) requiring central vein cannulation or endotracheal intubation in the ICUs. INTERVENTION: After each invasive procedure, the physician was instructed to complete a detailed evaluation sheet. Criteria based on the details of the procedure and immediate postprocedural clinical evaluation of the patient were used to determine the likelihood of a radiologically detectable complication. Actual radiologic findings were subsequently compared against clinical predictions. MAIN OUTCOME MEASUREMENTS: Ability of housestaff to correctly predict the absence of radiologically detectable postprocedural complications (predictive negatives). RESULTS: Ability to predict the absence of complications after cordis catheter insertions via the subclavian vein or internal jugular vein was very high (151/152; p < .001). Unsuspected complications were more frequent with central vein multilumen catheter insertions (3/24; p < .001). Ability to predict uncomplicated pulmonary artery catheterization was also high (110/111; p < .001). Physicians were unable to predict the majority of complications associated with endotracheal intubations (28/32; p > .50). CONCLUSIONS: The use of a protocol that includes an evaluation of the characteristics of the procedure and postprocedural physical examination can greatly reduce the need for routine chest radiographs after subclavian and internal jugular vein cordis catheterizations and pulmonary artery catheter placement. Chest radiographs should be performed after endotracheal intubation and multilumen catheter insertion.

Catheterization, Central Venous↗
PubMed1992

Antineutrophil cytoplasmic autoantibodies.

The identification of ANCA and their association with systemic vascular inflammation has become quite useful in both the diagnosis and management of patients with necrotizing vasculitic conditions. Primary autoantibody specificities have been identified, and many more await further characterization. As with ANA, it is highly probable that ANCA will not only complement patient care, but will provide means helpful in exploring the molecular structures and biochemical pathways within granulocytic phagocytes.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1991

Autoantibodies to native myeloperoxidase in patients with pulmonary hemorrhage and acute renal failure.

Sera from 245 patients were screened by indirect immunofluorescence for perinuclear/nuclear staining (P-ANCA) of ethanol-fixed neutrophils, a staining pattern which is associated with the presence of antibodies to myeloperoxidase. Using immunoblot and immunoprecipitation techniques on 15 P-ANCA-positive sera, 13 patients demonstrated antibody to purified or native myeloperoxidase but not to denatured myeloperoxidase. In patients with P-ANCA, the most frequent reason for medical attention was hemoptysis (8/13; 62%). Of the 15 sera with P-ANCA, acute renal failure was identified in 9 patients (60%). Five patients (33%) had both. All patients (eight of eight) with hemoptysis had antibodies which bound functional MPO as compared to three of seven P-ANCA-positive patients without hemoptysis (P less than 0.001), suggesting that antibodies which recognize conformational sites on native myeloperoxidase occur in a subgroup of patients with alveolar hemorrhage as their presenting clinical sign. These findings may provide insight into the disease process associated with P-ANCA. We further identify a subgroup of patients with a severe pulmonorenal syndrome and antibodies recognizing native myeloperoxidase.

Acute Kidney Injury↗
PubMed1991

Intrinsic alteration of the reactive properties of arteries during hypothermia.

This study compares the reactive and contractile properties of helical strips of femoral arteries taken from normothermic rabbits and rabbits that were anesthetized with pentobarbital and cooled to 25 degrees C. The purpose of this comparison was to see if previous exposure to whole body hypothermia would alter vascular muscle responsiveness to norepinephrine. We found that, after 2 h of in vivo hypothermia, the hypothermic-derived vascular strips contracted more slowly, but required from 10 to 100 times less norepinephrine to have a detectable contractile response. This continued while the tissue was in vitro for at least 12 h. Although the maximal tension developed by the strips was equivalent, the ED50 values for the hypothermic-derived arteries were lower than those of the normothermic tissue. This study has identified prolonged alterations in in vitro vascular responsiveness attributable to previous exposure to whole body hypothermia, which may help to explain the disruptions of blood pressure during and following exposure of the whole body to cold.

Animals↗
PubMed1991

IS10 promotes adjacent deletions at low frequency.

Some transposable elements move by a replicative mechanism involving cointegrate formation. Intramolecular cointegration can generate a product called an "adjacent deletion" in which a contiguous chromosomal segment adjacent to the transposon is deleted while the element responsible remains intact. Insertion sequence IS10 is thought to transpose by a nonreplicative mechanism. In the simplest models, nonreplicative transposition cannot give rise to an adjacent deletion because an intrinsic feature of such transposition is excision of the IS element from the donor location. We report here that IS10 can generate adjacent deletions, but at a frequency which is approximately 1/30th the frequency of transposition for the same element. We suggest that these deletions might arise either by nonreplicative transposition events that involve two IS10 elements located on sister chromosomes or by aberrant nonreplicative events involving cleavage and ligation at only one end of the element.

Blotting, Southern↗
PubMed1991

Evaluation of drug information for cardiology patients.

1. Cardiologists and pharmacists at the University Hospital of Wales collaborated to write 20 individual leaflets incorporating guidelines for a range of drugs used in the treatment of cardiology patients. The Plain English Campaign advised on the intelligibility and presentation of the information. 2. One hundred and twenty-five patients from the Regional Cardiology Unit, University Hospital of Wales were randomly allocated to receive usual verbal counselling about their drug treatment with or without an individualised drug information wallet. Two weeks after discharge from hospital patients completed a postal questionnaire to determine their satisfaction with the information about their drug treatment and their understanding of it. Forty-nine questionnaires were returned from the leaflet group and 52 from the control group. 3. The provision of written guidelines resulted in significant improvements in patients' satisfaction with their drug treatment (chi 2 = 33.3, P less than 0.001) and their understanding of it (P less than 0.001, Mann-Whitney test). Overall, patients who received leaflets were more likely to be aware of the potential side effects of their drugs but less likely to be apprehensive about them. Succinct guidelines concerning drug therapy can be assimilated by cardiology patients and provide them with a permanent record for future reference.

Adult↗
PubMed1991

Clinical pharmacokinetics of epoetin (recombinant human erythropoietin).

Epoetin (recombinant human erythropoietin, EPO) is of proven benefit in the treatment of renal anaemia, and preliminary reports suggest that it may have a role in the management of other anaemic conditions. Pharmacokinetic and therapeutic studies have examined the use of epoetin administered intravenously, intraperitoneally and subcutaneously, and there is accumulating evidence that the last route has several advantages. After intravenous administration, epoetin is distributed in a volume comparable to the plasma volume, and plasma concentrations decay monoexponentially with a half-life of between 4 and 12 hours. Administration of epoetin in peritoneal dialysis fluid results in detectable concentrations in the bloodstream after 1 to 2 hours, and peak concentrations of the order of 2 to 4% of those obtained with the same intravenous dose are found after approximately 12 hours. The bioavailability of epoetin administered intraperitoneally in dialysis fluid is about 3 to 8%, but this may be increased by injecting the drug into a dry peritoneal cavity. Subcutaneous administration results in peak concentrations at about 18 hours which are 5 to 10% of those found after the same intravenous dose. The bioavailability of subcutaneous epoetin is about 20 to 30% and detectable serum concentrations are still present 4 days after administration, in contrast to intravenous administration after which concentrations have returned to baseline within 2 to 3 days. Remarkably little is known about the metabolic fate of either erythropoietin or epoetin. In addition, there is much controversy surrounding the relative roles of the kidney and liver in the catabolism of epoetin. About 3 to 10% of epoetin is excreted unchanged in the urine. In common with other glycoproteins, the carbohydrate residues which constitute 40% of its molecular size are essential for maintaining the stability of epoetin in circulation. Desialated epoetin, although biologically active in vitro, is cleared very rapidly from plasma with resultant loss of activity. Further work is required, however, in identifying the pathways of metabolism and elimination of this glycoprotein hormone.

Animals↗
PubMed1991

The influence of a calorie supplement on the consumption of the meal, ready-to-eat in a cold environment.

There is a dichotomy between calories issued to soldiers in their daily field rations and the amounts actually consumed. Soldiers frequently consume insufficient calories to maintain body weight. A supplemental pack (740 kcal) was developed, to increase field calorie consumption, and tested with the old and new versions of the Meal, Ready-to-Eat on a 10-day field study in Alaska. Initial and final measurements included body weights, heights, blood, and urine parameters. Daily measurements included the collection of urine samples and completion of a dietary intake log. Energy intakes of the supplemented groups were 4%-11% higher (p less than 0.05) although the calorie intakes were still below the recommended 4,500 kcal/day for cold weather operations. Mean body weight loss ranged from 3.0 lb (1.7%) to 4.8 lb (2.8%). Two groups of the four groups became hypohydrated by day 3, due to low water intake, and only improved after direct intervention to increase drinking. Water and food intakes were strongly correlated (p less than 0.05). Results confirm the success of the supplemental pack as a means of increasing food intake and underscore the importance of water discipline in a cold environment.

Alaska↗
PubMed1989

Pharmacokinetics of recombinant human erythropoietin in patients on continuous ambulatory peritoneal dialysis.

To determine the optimum regimen for giving recombinant human erythropoietin (EPO) to patients on continuous ambulatory peritoneal dialysis (CAPD), the pharmacokinetics of single-dose EPO administered intravenously (120 U/kg), intraperitoneally (50,000 U), and subcutaneously (120 U/kg) was investigated. After intravenous administration serum EPO levels decayed exponentially from a peak of 3959 mU/ml, with a half-life of 8.2 h. 2.3% of the total intravenous dose was lost in the dialysate during the first 24 h. Peak serum EPO levels of 375 mU/ml at 12 h and 176 mU/ml at 18 h were attained following intraperitoneal and subcutaneous administration, respectively. The bioavailability of subcutaneous EPO (21.5%) was seven times greater than that of intraperitoneal EPO (2.9%). These results suggest that subcutaneous EPO represents the most satisfactory route of administration for CAPD patients.

Absorption↗
PubMed1989

Pharmacokinetics of intraperitoneal ciprofloxacin in patients on CAPD.

The concentration of ciprofloxacin was assayed in plasma and peritoneal dialysate following intraperitoneal administration of the drug in the absence of bacterial peritonitis. After administration of a single dose of 5 mg/kg, ciprofloxacin was rapidly absorbed, producing a peak plasma concentration of 1.9 +/- 0.6 mg/l after 3-4 h with an apparent bioavailability of 0.84. In a separate study, following the administration of 25 mg/l for eight consecutive CAPD cycles the intraperitoneal concentration of ciprofloxacin fell to a mean of 8.4 +/- 4.6 mg/l after 4 h cycles and to a mean of 3.0 +/- 3.2 mg/l after 12 h cycles. During the period of administration the mean plasma concentration was 0.5 +/- 0.2 mg/l. Analysis of dialysate for 48 h after cessation of drug administration demonstrated ciprofloxacin to be present in effluent from only two of the six patients, confirming its poor peritoneal elimination.

Ciprofloxacin↗
PubMed1988

Effects of prolonged naloxone infusion in septic shock.

Fourteen patients suffering sixteen episodes of septic shock requiring inotrope and/or vasopressor support were randomised to receive a 30 micrograms/kg naloxone intravenous bolus followed by a 30 micrograms/kg/h infusion or an equivalent volume placebo bolus and infusion for 8-16 h in a double-blind study. pH and pulmonary wedge pressure were kept constant, and inotrope and/or vasopressor were titrated to maintain a preselected mean blood pressure. Inotrope/vasopressor requirements in the naloxone-treated group were significantly lower than those in the control group at 8 h (eight patients in each group, p less than 0.005) and at 16 h (five patients in each group, p less than 0.02). Late but significant improvements in stroke volume (p less than 0.02) and heart rate (p less than 0.05) were also noted in the eight naloxone-treated patients.

Adult↗