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Biomedical subjects

P J Armstrong

Publications and source records attributed to P J Armstrong.

At least 19 recordsLinked to original sources
PubMed1992

Epidemiology of Pseudomonas aeruginosa in an intensive care unit using selective decontamination of the digestive tract.

Selective decontamination of the digestive tract (SDD) aims to reduce the rate of nosocomial infections in critical care patients. Pseudomonas spp. are common nosocomial pathogens and in this study isolates collected from patients and the environment during an SDD trial were examined. The study enrolled 161 SDD cases and 170 controls. Pseudomonads were isolated from 27% of SDD patients and 30% of controls. SDD partially suppressed colonization in the 'gastro-respiratory' mucosae but not in the rectum. A total of 108 isolates of pseudomonads were recovered from the environment. Resistance in rectal isolates was minimal but isolates from 'gastro-respiratory' sites showed increasing aminoglycoside resistance. Eighty-six per cent of aminoglycoside-resistant isolates from both patient groups and environment were pyocine type 1x. Episodes of infection were reduced in the SDD patients (6) compared with the controls (16), aminoglycoside-resistant strains being associated with zero episodes in SDD patients but with five in the control group.

Cross Infection↗
PubMed1991

Effects of i.v. lignocaine on psychological performance and subjective state in healthy volunteers.

In order to assess the effects of different doses of lignocaine on performance, nine healthy volunteers aged 21-34 yr received i.v. infusions of saline, low and high dose lignocaine (mean plasma concentrations 0.92 and 1.78 micrograms ml-1, respectively) in a double-blind randomized order. The Digit-Symbol Substitution Test (DSST) and Visual Analogue Scales (VAS) were performed repeatedly and a battery of performance tests once. The median (lower, upper quartile) number of correct responses for the DSST during the infusion period was: placebo 69 (67, 77); low 74 (71, 80); high 66 (61, 75) (P less than 0.001, General Linear Models; all pairwise comparisons P less than 0.05). None of the measures in the full battery showed any significant changes. VAS showed that subjects felt more interested (P less than 0.05), drowsy (P less than 0.01), dizzy, tense, abnormal, drunk and muzzy (P less than 0.001) with lignocaine than with placebo. These results confirm that lignocaine can produce acute performance effects (both improvements and impairments). Subjects were clearly aware of the presence of lignocaine, suggesting that subjective reports may be a useful indicator of its CNS effects.

Adult↗
PubMed1991

The alkalinisation of bupivacaine for intercostal nerve blockade.

A double-blind randomised study was performed to investigate the effect of pH adjustment of bupivacaine, with adrenaline 1:200,000, on the duration of block and pain relief after intercostal nerve blockade following thoracotomy. One group (n = 10) received bupivacaine with adrenaline 1:200,000 (pH = 4.1) and the other (n = 10) received alkalinised bupivacaine with adrenaline 1:200,000 (pH = 6.9). There was no significant difference in block duration (mean 23.9 and 26.4 hours respectively) visual analogue pain scores or morphine usage. Patients were more likely to have a block during the first 12 hours if they received alkalinised bupivacaine (p less than 0.01, Chi-squared test). A progressive regression of block, not previously described, was observed, explicable by means of spread of local anaesthesia to adjacent intercostal nerves. Alkalinisation of bupivacaine with adrenaline for intercostal nerve blockade has little clinical benefit.

Bupivacaine↗
PubMed1990

An epizootic of peroneal and tibial neuropathy in Walker Hound pups.

Early in life, Walker Hound pups from several litters, later determined to have peroneal and tibial neuropathy, had been given supplements of either evaporated milk and corn syrup mixed with well water or powdered bitch milk formula mixed with well water. Other pups not given supplements were not affected. Pelvic limb monoparesis, areflexia, analgesia, and muscular atrophy developed by 2 weeks of age. Abnormalities detected by light and electron microscopy included scattered swollen axons containing increased organelles and whorled neurofilaments. The clear association between clinical signs of disease and dietary supplementation of pups among healthy dogs in a kennel, as well as lack of an obvious pattern of inheritance, suggested an environmentally acquired toxin, specifically the well water. Attempts to reproduce neuropathy in a litter of Beagle pups 2 years after initial evaluation of the disease syndrome were unsuccessful. Atomic absorption studies performed on the well water to detect heavy metals did not reveal toxic concentrations. Toxins that may have been responsible for the neuropathy in these pups were not identified.

Animals↗
PubMed1990

Choice of incision and pain following gallbladder surgery.

A prospective randomized trial compared pain in the first 24 h after gallbladder surgery via an upper midline or a transverse incision. Pain was measured by the patients' self-administered consumption of pethidine, degree of postoperative respiratory impairment and a visual analogue pain scale. The upper midline incision group self-administered significantly more pethidine than the transverse incision group (P less than 0.001), but there was no difference between the groups in respiratory function or visual analogue pain scale results 24 h after operation. Length of hospital stay was not different. An upper midline incision is more painful than a transverse incision in the first 24 h following gallbladder surgery.

Female↗
PubMed1990

Enteral nutrition by tube.

When oral intake is unsatisfactory or contraindicated, maintenance of nutrition by tube feeding is an alternative to the parenteral route. A large volume of research data supports the decision to use the enteral route whenever possible. Entry of food into the alimentary tract is a stimulus to structural and functional maintenance of that tract. Enteral nutrition can be given via indwelling nasoesophageal, pharyngostomy, esophagostomy, percutaneous or surgical gastrostomy, or enterostomy tube. Use of an appropriate catheter, familiarity with the technique used, and careful patient selection and monitoring are important factors in successful tube feeding. Blenderized pet food diets should be fed whenever possible; commercially available liquid diets provide an alternative when tube caliber or patient factors preclude the use of blenderized foods.

Animals↗
PubMed1989

Obesity: occurrence, treatment, and prevention.

Obesity is the most common nutritionally related disease of dogs and cats. Several of the important health problems that are inherent with obesity are resolved when the patient's body weight is returned to normal. Proper dietary management is central to successful treatment and prevention. Low-fat, high-fiber diets provide fewer available calories but induce a greater degree of satiety than simple restriction of the obese patient's regular food. Care must be taken to assure that overweight cats are not fasted, because preliminary reports indicate an alarming association between severe caloric restriction and hepatic lipidosis in obese cats. Obesity prevention should ideally be proactive, owing to the predictability of obesity in certain groups of pets. The large number of reduced-energy maintenance type diets that are available for obesity prevention facilitate this goal.

Animals↗
PubMed1989

Unilateral subarachnoid anaesthesia.

The development of a unilateral block after subarachnoid anaesthesia is described. Other reported cases are discussed and the anatomy of subarachnoid space summarised.

Adult↗
PubMed1988

Fentanyl blood concentration-analgesic response relationship in the treatment of postoperative pain.

The inter- and intrasubject variability in blood concentration-analgesic response relationship for fentanyl were investigated using the technique of patient-controlled analgesia (PCA) in 30 consenting patients scheduled for surgical procedures involving an abdominal incision (15 upper and 15 lower abdominal incisions). All patients had a thiopental, nitrous oxide/oxygen, pancuronium anesthetic with 200 microgram fentanyl intraoperatively. Postoperative pain relief was provided with fentanyl from a Janssen On-Demand Analgesic Computer (ODAC) set to provide a basal infusion rate of 20 microgram/hr, a bolus "demand" dose of 20 microgram, and a lockout period of 5 minutes. Frequent blood samples were collected immediately before patients demanded doses, and these were taken as an estimate of the minimum effective concentration (MEC). A mean of 22 samples (range 12 to 45) were collected per patient over a mean study duration of 50 hours (range 24 to 72). The patients required larger hourly fentanyl doses in the first 6-hour period (83.9 +/- 30.1 microgram/hr) than in any other 6-hour period (mean values varied from 37.3 to 63 microgram/hr). The mean (+/- SD) hourly fentanyl dose rate and total cumulative dose were 55.8 +/- 22 microgram/hr (range 28.8 to 136 microgram/hr) and 2739 +/- 1191 microgram (range 900 to 6260 microgram), respectively. The mean (+/- SD) MEC was 0.63 +/- 0.25 ng/ml (five-fold range from 0.23 to 1.18) and the mean intrapatient coefficient of variation in MEC was 30.2% (range 16 to 46%). The MEC values remained relatively constant in all patients over the 48-hour study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Congenital portosystemic shunts in dogs: 46 cases (1979-1986).

Congenital portosystemic shunts (CPSS) were diagnosed in 46 dogs. The historic, physical, and laboratory findings were tabulated. Half of the affected males were cryptorchid. Urolithiasis was detected in 20% of the dogs. The biochemical tests with the best sensitivity for the diagnosis of CPSS were sulfobromophthalein retention, fasting serum ammonia concentration, and serum alkaline phosphatase activity. The survival time and quality of life were assessed by physical and biochemical reevaluation of the dogs and by means of a questionnaire that was completed by the owners. Five dogs were treated medically. Thirty-three dogs were treated surgically. Dogs that had complete surgical occlusion of the CPSS became normal, and quality of life was excellent. Dogs that had partial occlusion of the CPSS improved, and some became clinically normal. Dogs that did not have surgical correction of the CPSS had continuation of signs, but several survived for years.

Animals↗
PubMed1987

Effect of nonadrenal illness on adrenal function in the cat.

Adrenal function was assessed by a combined dexamethasone suppression-ACTH stimulation test in 18 healthy cats, 17 diabetic cats, and 19 sick nondiabetic cats. In all groups, plasma cortisol concentrations decreased after dexamethasone was administered and increased after ACTH was administered. There were no significant (P greater than 0.05) differences among groups in time trend changes in cortisol concentration. There was considerable variation in adrenal response between cats in each group. Diabetic cats had more variation in base-line and postdexamethasone plasma cortisol concentrations (P less than 0.05) than did other groups. In sick, nondiabetic cats, cortisol concentrations tended to be higher in cats with hyperthyroidism (P = 0.06) than in cats with other diseases.

Adrenal Cortex Function Tests↗
PubMed1986

Airway responses to aerosolized methacholine and citric acid in ponies with recurrent airway obstruction (heaves).

We measured lung function and airway reactivity in response to methacholine and citric acid administered by aerosol in 2 groups of ponies (principal and control). Principal ponies had a history of heaves, a disease characterized by recurrent airway obstruction. Control ponies had no history of respiratory disease. Both principal and control ponies were paired (principal and control), and measurements were made when principal ponies were in clinical remission (Period A), following barn exposure when principal ponies had acute airway obstruction (Period B), and 1 and 2 wk after they were returned to pasture (Periods C and D). Differences between groups were primarily found at Period B. Barn housing (Period B) decreased dynamic compliance (Cdyn) and increased pulmonary resistance (RL) of principal but not of control ponies. When compared with control ponies at Period B, principal ponies demonstrated airway hyperreactivity. The dose of methacholine required to reduce Cdyn to 65% of baseline (ED65Cdyn) was lower, the change in RL induced by an aerosol of 0.1 mg/ml methacholine (delta RL 0.1) was higher, and the percent change in Cdyn in response to an aerosol of 0.1 mg/ml methacholine (delta %Cdyn 0.1) was larger in principal than in control ponies. A 10-min inhalation of 10% citric acid aerosol did not cause changes in Cdyn in either group of ponies. Control ponies did not increase RL in response to citric acid, whereas at Period B, RL of principal ponies increased following citric acid. We conclude that ponies in clinical remission from heaves are not hyperreactive to aerosols of methacholine or citric acid. Hyperreactivity only exists during acute exacerbations of airway obstruction.

Aerosols↗
PubMed1985

Secondary myelofibrosis in three dogs.

Myelofibrosis was diagnosed in 3 dogs. In each dog, there was evidence of concurrent bone marrow necrosis, suggesting that the myelofibrosis was a secondary change. This suggestion was supported by a lack of dysplastic changes in hematopoietic cells. Bone marrow necrosis in 2 of the dogs may have been the result of widespread malignancy. Reversal of the myelofibrosis in 1 dog suggested that myelofibrosis is not always a terminal disorder.

Adenocarcinoma↗