Search PubMed⌕ Search

Biomedical subjects

S M Willatts

Publications and source records attributed to S M Willatts.

At least 37 records · Page 2Linked to original sources
PubMed1992

A controlled trial of selective decontamination of the digestive tract in intensive care and its effect on nosocomial infection.

Nosocomial infection is a major problem in intensive therapy units (ITUs) and a significant cause of mortality. Selective decontamination of the digestive tract (SDD) has been advocated as a means to reduce ITU morbidity and mortality. Ninety-one patients in a general ITU underwent SDD, consisting of topical polymyxin E, tobramycin and amphotericin B administered throughout the unit stay together with parenteral ceftazidime for the first three days, and were compared with 84 historical and 92 contemporaneous control patients who were treated conventionally. Twenty-seven historical and 32 contemporaneous control patients developed unit-acquired infections, in comparison with only three patients in the SDD group (P less than 0.01). Mortality in the SDD group (36%) was not significantly different from that in the other two groups (historical control 40%, contemporaneous control 43%). Screening specimens revealed a significantly higher rate of colonization with resistant Acinetobacter spp. in the contemporaneous control than in the other two groups of patients; infection caused by resistant bacteria did not occur. SDD did not lead to a significant reduction in the use of systemically-administered antibiotics when compared with either control group. SDD may be used selectively in an ITU without ill effects on those patients not receiving SDD; nevertheless, microbiological monitoring is needed to detect emergence of resistant bacteria in the unit.

Adolescent↗
PubMed1991

An outbreak of aspergillosis in a general ITU.

Over a 5-month period, six patients in a general intensive therapy unit became colonized by Aspergillus species including Aspergillus fumigatus, and invasive infection occurred in at least two of them. Broncho-alveolar lavage was unhelpful in discriminating between infection and colonization. The source of infection was presumed to be disturbance of an accumulation of spores in fibrous insulation material above the perforated metal ceiling. Patients in such units without clearly identifiable defects of defence against infection may be at risk from aspergillosis. The risk can be reduced by improved hospital design, satisfactory ventilation and thorough regular cleaning of environmental surfaces.

Adult↗
PubMed1991

Plasma inorganic fluoride concentrations during and after prolonged (greater than 24 h) isoflurane sedation: effect on renal function.

We studied the effect of prolonged sedation (greater than 24 h) with isoflurane on plasma inorganic fluoride concentrations and renal function in 60 critically ill patients allocated randomly to receive either isoflurane or midazolam for sedation. In the isoflurane group, plasma fluoride increased from a mean concentration of 3.1 mumol/L to 20.0 mumol/L at the end of sedation, continued to increase to a peak of 25.3 mumol/L 16 h later, and then decreased exponentially (t1/2 = 111 h) to reach normal levels by the fifth day. In the midazolam group, the plasma fluoride increased from a mean concentration of 4.2 mumol/L to a peak of 6.8 mumol/L 12 h after starting the sedation and then decreased toward normal. Serum and urinary electrolytes, urine osmolality, and creatinine clearance during and after sedation were similar in the two groups. Isoflurane sedation was associated with an increase in plasma fluoride concentration without any clinical deterioration of renal function.

Adolescent↗
PubMed1990

Plasma catecholamine concentration during sedation in ventilated patients requiring intensive therapy.

The effects of isoflurane and midazolam sedation on the catecholamine responses of ventilated patients were studied over a 24-h period. Sixty ventilated patients admitted to our intensive therapy unit were allocated randomly to receive either isoflurane or midazolam sedation. Arterial blood samples for plasma catecholamine concentrations were taken at baseline, 6 h after starting sedation and at the end of the study period. Patients sedated with isoflurane showed a progressive reduction in both adrenaline and noradrenaline concentrations during the period of sedation which reached statistical significance for adrenaline at 6 h (p less than 0.02) and at the end of the study (p less than 0.001). Patients sedated with midazolam showed no significant changes of adrenaline or noradrenaline concentrations. Overall, a more satisfactory degree of sedation was achieved with isoflurane.

Administration, Inhalation↗
PubMed1990

Isoflurane sedation for patients undergoing mechanical ventilation: metabolism to inorganic fluoride and renal effects.

The metabolism and renal effects of isoflurane sedation were studied for 24 h in patients undergoing mechanical ventilation. Forty-six patients admitted to our intensive therapy unit were allocated randomly to receive either 0.1-0.6% isoflurane or midazolam 0.01-0.2 mg kg-1 h-1 for sedation. In 26 patients sedated with isoflurane, plasma inorganic fluoride increased from a mean concentration of 4.03 mumol litre-1 to 13.57 mumol litre-1 12 h after stopping sedation. Plasma inorganic fluoride concentrations in 20 patients sedated with midazolam were unchanged from baseline values (mean 5.32 mumol litre-1). Serum electrolyte, urea and creatinine concentrations, and urine output rates during and after sedation in patients who received isoflurane were similar to those who received midazolam. We conclude that, following isoflurane sedation for up to 24 h, metabolism to inorganic fluoride is insufficient to cause clinical renal dysfunction.

Aged↗
PubMed1989

Comparison of propofol and midazolam for sedation in critically ill patients.

101 critically ill patients admitted to five intensive-care units were allocated randomly to receive a continuous intravenous infusion of either propofol or midazolam for sedation for up to 24 h. In addition, morphine was given to provide analgesia. The mean duration of infusion was 20.2 h (range 3.0-24.5) in the propofol group and 21.3 h (4.0-47.0) in the midazolam group and infusion rates were 1.77 mg/kg/h (range 0.40-5.00) and 0.10 mg/kg/h (0.01-0.26), respectively. The infusion rates were adjusted as necessary, and the desired level of sedation was achieved easily in most patients in both groups. There were slight falls in arterial pressure, but there were no significant differences between the groups. Heart rate was lower in patients who received propofol. Some small changes occurred in biochemical and haematological variables in both groups, but they were not clinically significant. There was no indication that either drug substantially impaired adrenal steroidogenesis. When the infusion was discontinued, there was less variability in recovery of consciousness in patients who had received propofol. In a subgroup of patients, weaning from mechanical ventilation was achieved significantly faster after discontinuation of propofol than of midazolam. Propofol proved to be a satisfactory agent for sedation of these critically ill patients and compared favourably with midazolam.

Adolescent↗
PubMed1989

Isoflurane compared with midazolam for sedation in the intensive care unit.

OBJECTIVE: To compare isoflurane with midazolam for sedation of ventilated patients. DESIGN: Randomised control study. Setting--Intensive care unit in university teaching hospital. PATIENTS: Sixty patients aged 18-76 who required mechanical ventilation. INTERVENTIONS: Sedation with either 0.1-0.6% isoflurane in an air-oxygen mixture (30 patients) or a continuous intravenous infusion of midazolam 0.01-0.20 mg/kg/h (30 patients). Sedation was assessed initially and hourly thereafter on a six point scale. Incremental intravenous doses of morphine 0.05 mg/kg were given for analgesia as required. The trial sedative was stopped when the patient was judged ready for weaning from ventilatory support or at 24 hours (whichever was earlier). END POINT: Achievement of a predetermined level of sedation for as much of the time as possible. MAIN RESULTS: Isoflurane produced satisfactory sedation for a greater proportion of time (86%) than midazolam (64%), and patients sedated with isoflurane recovered more rapidly from sedation. CONCLUSION: Isoflurane is a promising alternative technique for sedation of ventilated patients in the intensive care unit.

Adolescent↗
PubMed1987

Electrolyte measurement by clinicians.

The development of automated techniques for the measurement of electrolytes using ion-selective electrode technology has resulted in the availability of such machines for use by clinicians. A study is described which compares values obtained for plasma sodium and potassium by interested clinicians using a Beckman Electrolyte 2 analyser, with results obtained by laboratory staff using a Beckman E2A autoanalyser. A total of 14 estimations each for sodium and potassium were made on 96 samples of venous blood from patients on an intensive care unit. Comparisons were made using the coefficient of variation and analysis of variance (ANOVA). Seventy-three percent of observations of sodium and 87% of observations of potassium made by clinicians lie within 2 mmol l-1 and 0.2 mmol l-1 respectively, of observations made by laboratory staff. Observations outside these ranges are examined. The authors conclude that the results obtained by interested clinicians lie well within acceptable limits for medical usefulness, that inappropriate therapy based on such results is unlikely, and that such estimations would appear to be safe and acceptably accurate.

Autoanalysis↗
PubMed1986

Nutrition.

Explore the source record for details and available documents.

Carbohydrate Metabolism↗
PubMed1985

Alternative modes of ventilation. Part I. Disadvantages of controlled mechanical ventilation: intermittent mandatory ventilation.

Controlled mechanical ventilation is an accepted therapy for acute respiratory failure but by virtue of the increase in intrathoracic pressure has a large number of disadvantages. It is to overcome these disadvantages that alternative modes of ventilation have been introduced. These aim to reduce the effects of abnormally high airway pressure on the lung whilst recruiting solid alveoli and at the same time maintaining effective blood volume. Intermittent mandatory ventilation is a mode of ventilation first introduced to aid weaning which may reduce the need for sedation, permit better tolerance of high levels of PEEP and maintain urine osmolar output. High frequency ventilation utilising low airway pressures can maintain pulmonary gas exchange whilst reducing the effects of stretch on the lung. Its major role would seem to be in cases of bronchopleural fistula and necrotising pneumonia where a low mean airway pressure is essential. Low frequency positive pressure ventilation with extra corporeal CO2 removal, whilst a very labour intensive technique, has produced a favourable outcome in patients with terminal respiratory failure. Use of PEEP is associated with further deleterious haemodynamic effects which are largely overcome with use of continuous positive airway pressure during spontaneous respiration. PEEP is widely used. Its effect on pulmonary compliance, dead space and oxygen delivery are unpredictable making haemodynamic monitoring mandatory. Inversed ratio ventilation requires further evaluation whereas differential lung ventilation is logical, complicated but very valuable where the time constants for each lung are significantly different.

Adult↗