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Biomedical subjects

S M Willatts

Publications and source records attributed to S M Willatts.

At least 19 recordsLinked to original sources

Brainstem death and ventilator trigger settings.

A patient with cerebral infarction was certified clinically brainstem dead. However, 4 h after the diagnosis of death, while the patient was being ventilated using the biphasic positive airway pressure mode, the 'assist' indicator light on the Drager Evita 2 ventilator illuminated intermittently. There was no evidence of spontaneous breathing. 'Triggering' was probably caused by a decrease in airway pressure in time with cardiac contraction. The trigger flow rate is crucial as factors other than the patient's inspiratory effort can initiate flow from the ventilator with very sensitive settings.

Brain Death↗

Preliminary UK experience of dexmedetomidine, a novel agent for postoperative sedation in the intensive care unit.

Dexmedetomidine, a highly selective and potent alpha2-adrenergic agonist, has a potentially useful role as a sedative agent in patients requiring intensive care. As part of a larger European multicentre trial, a total of 119 postoperative cardiac and general surgical patients requiring ventilation and sedation in an intensive care unit were enrolled in four centres in the United Kingdom. One hundred and five patients were randomly allocated to receive either dexmedetomidine or placebo with rescue sedation and analgesia provided by midazolam and morphine, respectively. Compared with the control group, intubated patients receiving dexmedetomidine required 80% less midazolam [mean 4.9 (5.8) microg.kg-1.h-1 vs. 23.7 (27.5) microg.kg-1.h-1, p < 0.0001], and 50% less morphine [11.2 (13.4) microg.kg-1.h-1 vs. 21.5 (19.4) microg.kg-1.h-1,p = 0.0006]. Cardiovascular effects and adverse events could be predicted from the known properties of alpha-2 agonists. In conclusion, dexmedetomidine is a useful agent for the provision of postoperative analgesia and sedation.

Adolescent↗

Sweet's syndrome associated with systemic inflammatory response syndrome.

Septic shock is characterised by infection causing a systemic inflammatory response, end-organ failure and acute circulatory collapse. Treatment consists of antimicrobial therapy and the supportive management of multi-organ failure. We report a case of what we believed to be septic shock due to pyelonephritis in a patient whose condition continued to deteriorate despite conventional treatment until the diagnosis of Sweet's syndrome was made. Once she was started on high dose steroids, her condition improved and she made a full recovery. We believe this to be the first case of a severe systemic inflammatory response syndrome associated with Sweet's syndrome.

Anti-Inflammatory Agents↗

Elective ventilation of potential organ donors.

Elective ventilation describes the procedure of transferring selected patients dying from rapidly progressive intracranial haemorrhage from general medical wards to intensive care units for a brief period of ventilation before confirmation of brain stem death and harvesting of organs. This approach in Exeter has led to a rate of kidney retrieval and transplant higher than has been achieved elsewhere in the United Kingdom, with a stabilisation of numbers on patients on dialysis. Recently doubt has been cast on the legality of our practice of elective ventilation on the grounds that relatives are not permitted to consent to treatment of an incompetent person when that treatment is not in the patient's best interests. We are thus faced with the dilemma of a protocol that is ethical, practical, and operates for the greater good but which may be illegal. This article explores various objections to the protocol and calls for public, medical, and legal debate on the issues.

Brain Death↗

Effect of the antiendotoxic agent, taurolidine, in the treatment of sepsis syndrome: a placebo-controlled, double-blind trial.

OBJECTIVE: To assess the benefit gained from administration of the antiendotoxic drug, taurolidine, on outcome in critically ill patients with sepsis syndrome. DESIGN: A prospective, randomized, double-blind trial. SETTING: The general intensive therapy unit in a university teaching hospital. PATIENTS: One hundred patients admitted with sepsis syndrome over a 2-yr period. INTERVENTIONS: Patients were randomized to receive the amino-acid derivative, taurolidine, or an identically presented placebo. MEASUREMENTS AND MAIN RESULTS: Acute Physiology and Chronic Health Evaluation II (APACHE II), sepsis, and organ failure scores were measured daily. Blood for culture and endotoxin assay (using the limulus amoebocyte lysate assay) was sampled every 12 hrs for up to 5 days. Hemodynamic variables were recorded every 4 hrs. Forty-nine patients received taurolidine and 51 patients received placebo. There was no difference in APACHE II score, Sepsis Score, or presence of infections between the groups. The frequency of Gram-negative bacteremia was low at 12%. There was no difference in endotoxin activity, clinical or bacteriologic outcome, resolution of organ failure, or mortality rate between groups. Predicted risk of death for patients receiving taurolidine was 45%, and the actual mortality rate was 44%. In the group that received placebo, the predicted mortality rate was 38% and the actual mortality rate was 39%. CONCLUSION: Taurolidine had no beneficial therapeutic effect on the outcome of patients admitted to the intensive therapy unit with sepsis syndrome, using clinical, bacteriologic outcomes, progression of endotoxemia, resolution of organ failure, and 28-day mortality rate as end points.

APACHE↗

Health and activity after intensive care.

All patients discharged from a general intensive care unit over a 4.5 year period were sent a questionnaire 3 months after discharge which investigated aspects of their health and physical abilities. Replies were compared on the basis of age, diagnosis and sickness severity on admission. Five hundred and four questionnaires were analysed. Overall, 47% of patients described their health as good/very good, 42% as fair and 11% as poor/very poor. Activity level, compared to that before their admission, was unchanged in 59%, worse in 33% and improved in 8% of patients. There were no differences in health status or changes in activity with age, diagnosis or severity of sickness. Patients aged 76 years or older were more likely to perceive their health as 'better than average' than younger patients (p < 0.01). Eight percent of patients would be unwilling to undergo intensive care again. An unacceptable health status after intensive care cannot be predicted in any group of patients.

APACHE↗

Continuous monitoring of depth of sedation by EEG spectral analysis in patients requiring mechanical ventilation.

Twenty-three patients undergoing intensive therapy had continuous EEG recording in an attempt to assess depth of sedation using spectral analysis. Median power frequency (MPF) and spectral edge frequency (SEF) were calculated and correlated with the clinical sedation score and blood concentration of sedative drug. Fifteen patients received isoflurane and eight midazolam. There was no correlation between MPF or SEF and sedation score or blood concentration of drug. These results suggest that no simple measure of the EEG is likely to correlate with depth of sedation in critically ill patients.

Adolescent↗

APACHE II scoring system on a general intensive care unit: audit of daily APACHE II scores and 6-month survival of 691 patients admitted to a general intensive care unit between May 1990 and December 1991.

In this paper we present a detailed analysis of the use of the APACHE II (acute physiological and chronic health evaluation) scoring system on all of the patients admitted to the general intensive care unit at the Bristol Royal Infirmary over a 20-month period. The 6-month survival of 691 adult medical and surgical patients following intensive care was recorded and this data was analysed with admission and daily APACHE II scores using a relational database. Our data confirms the relationship between admission APACHE II scores and outcome, with mean scores decreasing as duration of survival increases. We also demonstrate that the best day one scores are approximately 50% less than the admission score, irrespective of outcome, indicating the benefit of intensive care. By contrast, however, the scores on day one have either not improved or have worsened since admission, reflecting the importance of the pre-morbid health status of the patient in determining outcome from intensive care.

England↗

Isoflurane for prolonged sedation in the intensive care unit; efficacy and safety.

OBJECTIVE: To compare isoflurane with midazolam for prolonged sedation in ventilated patients. DESIGN: Randomised controlled study. SETTING: General intensive care unit in university teaching hospital. PATIENTS: Sixty patients aged 17-80 years who required mechanical ventilation for more than 24 h. INTERVENTIONS: Sedation with either 0.1-0.6% isoflurane in an air-oxygen mixture (30 patients) or a continuous infusion of midazolam 0.02-0.20 mg/kg/h (30 patients). Sedation was assessed initially and hourly thereafter on a six point scale. The trial sedative was stopped when the patient was ready for weaning from ventilatory support. MEASUREMENTS AND RESULTS: Measurements were made of haemodynamic, respiratory and biochemical variables regularly during the period of sedation and for a week after stopping the sedative agent. There was no difference in any of the physiological or biochemical variables recorded between the two groups. Patients sedated with isoflurane recovered more rapidly and were weaned from mechanical ventilation sooner than those sedated with midazolam. CONCLUSIONS: Isoflurane is a useful agent for prolonged sedation of ventilated patients and does not have any adverse effect on the cardiorespiratory system or on hepatic, renal or adrenal function.

Adolescent↗

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↗

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↗