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Biomedical subjects

S Ridley

Publications and source records attributed to S Ridley.

52 records · Page 3Linked to original sources
PubMed1994

A changing role for intensive therapy: is there a case for high dependency care?

This observational study examined whether specific characteristics of 1168 patients admitted to a general intensive therapy unit had changed over 4 years. The patients' age, diagnosis, severity of illness on admission (APACHE score), duration of management and outcome were recorded prospectively. The risk of hospital mortality was calculated using the APACHE score modified by the appropriate coefficient for presenting diagnosis. The numbers of admissions increased over the study period from 240 patients in the first year to 344 in the last year. The pattern of diagnoses varied significantly with an increasing proportion of patients being admitted for postoperative observation in later years. There was a significant reduction in duration of admission with 70% of patients being admitted for < or = 3 days in 1988-89 while a similar proportion were admitted for a week in 1985-86. Approximately 40% of patients in each year were admitted with a risk of hospital mortality of < or = 10%; such patients received only a short period of intensive care and had a low mortality in the intensive therapy unit. A group of patients with a low predicted (and actual) mortality rate was identified; such patients may be more appropriately managed on a high dependency unit.

APACHE↗
PubMed1993

A cost-benefit analysis of intensive therapy.

The daily costs of 90 critically ill patients treated on an intensive therapy unit were calculated on an individual patient basis. Twenty-one patients (23%) died on the intensive therapy unit and another 13 (15%) died within one year of discharge. The results demonstrate that there is wide variation in costs among the patients and the diagnoses. The mean daily cost of nonsurvivors was almost 300 pounds greater than that of survivors (816 pounds (95% confidence interval = 649-982 pounds) versus 550 pounds (498-601 pounds). Renal failure, sepsis and pneumonia proved to be some of the most expensive conditions to treat, and postoperative respiratory failure the cheapest. The cost of the first day of management was significantly related to the APACHE II score and individual costs on the first day may be predicted from admission APACHE II score. Patients who die in the intensive therapy unit continue to incur the same level of expenditure throughout admission. The study could not provide conclusive answers concerning the trend in daily costs for survivors.

Adult↗
PubMed1993

Economic aspects of general anaesthesia.

Proper economic evaluation involves comparative analysis of alternative courses of action in terms of both costs and outcome. This is difficult for general anaesthesia as there are few alternatives and measurement of outcome is difficult to define. All that is generally available is a cost description of different anaesthetic techniques. This article outlines the choice of drugs, breathing systems and ventilatory pattern available to the anaesthetist, and compares regional with general anaesthesia. For each technique the cost and advantages/disadvantages are outlined. There is a discussion of some wider issues involved together with their implications: the abandonment of cyclopropane and nitrous oxide; equipment costs and recommendations by the Association of Anaesthetists of Great Britain and Ireland; staffing levels; legal aspects and the increase in day surgery. The limitation of cost-effectiveness analysis of general anaesthesia is outlined.

Ambulatory Surgical Procedures↗
PubMed1992

Cause of death after critical illness.

This study reports the causes of death after discharge following treatment of life-threatening illness on an Intensive Therapy Unit. Details of survivors discharged between June 1985 and December 1988 were sent to the Registrar General for Scotland who subsequently issued copies of death certificates of those patients who had died between discharge and 1 January 1990. The results show that the commonest causes of death after discharge were malignancy and respiratory failure, although there is wide variation in the post-discharge mortality rates for different diagnostic categories. The admission diagnoses were identical to, or contributed to, the causes of death in 64% of patients who died after discharge. Eighty-five percent of patients who died from the same condition which prompted admission did so within a year following discharge, but after 2 years no deaths were attributed to the admission diagnosis.

Adolescent↗
PubMed1991

Unusual presentation of acute upper airway obstruction caused by an anterior mediastinal mass.

We report an unusual case of acute upper airway obstruction. Inhalation of a foreign body caused choking in a 5-yr-old child, but subsequent investigations revealed a large anterior mediastinal tumour, externally compressing the trachea and the main bronchi. Such a presentation may be deceptive and is important, as general anaesthesia may result in complete airway obstruction with fatal consequences.

Airway Obstruction↗
PubMed1991

Cost of intensive therapy. A description of methodology and initial results.

A preliminary study was performed to calculate the cost of intensive therapy on an individual patient basis. The fixed (equipment, supporting services and land opportunity), semi-fixed (staff) and marginal (treatment) costs of 20 critically ill patients were calculated individually. The results show that there is wide variation in intensive therapy costs. The average daily cost for a spontaneously breathing patient was 399 pounds (95% confidence intervals 388 pounds-460 pounds) while that for a ventilated patient was 726 pounds (656 pounds-795 pounds). The mean total cost per patient was 1980 pounds, but the cost per survivor increased by 16% (347 pounds) because of four deaths on the intensive care unit. High total costs are associated with increased severity of illness and higher marginal (treatment) costs are associated with increased semi-fixed (staff) costs. The cost of intensive therapy was three to five times that for general ward care.

Adult↗
PubMed1991

Respiratory compliance during sedation, anesthesia, and paralysis in infants and young children.

Although total respiratory compliance (Crs) has been shown to fall in adults on induction of halothane anesthesia, no successful paired studies have been reported in children. The multiple occlusion technique was used to measure Crs in 17 infants and young children during sedated sleep (CrsS) and shortly after, following induction of halothane anesthesia (CrsA). Crs fell in all but one infant after induction of anesthesia, with a mean fall of 34.7% (range 0-58%). This was accompanied by a reduction in tidal volume and increase in frequency in every case. In 7 of the 17 children, who were to be paralyzed for surgical purposes, Crs was also measured in this anesthetized-paralyzed state. When tidal volume administered during manual ventilation was similar to that observed during measurement of CrsA, Crs during this low-volume ventilation was similar to CrsA. When tidal volume was increased and Crs remeasured, there was a significant increase in every case, with the high-volume Crs within 10% of CrsS in all but one child, in whom there was a 31.4% increase with respect to CrsS. Changes in tidal volume accounted for approximately 50% of the variability in each state. These results demonstrate a highly significant fall in Crs in infants and young children after induction of halothane anesthesia. In addition it appears that this reduction in Crs can be reversed by paralyzing the child and manually ventilating with tidal volumes approximating those seen during sedation.

Anesthesia↗
PubMed1990

Long term survival after intensive care.

OBJECTIVE: To examine the long term survival of critically ill patients admitted to an intensive therapy unit and to ascertain the effects of age, severity of illness, and diagnostic category at admission on survival. DESIGN: Retrospective observational study with prospectively gathered data on all patients admitted to the unit between June 1985 and July 1987 and followed up until 1 January 1989. SETTING: Regional intensive therapy unit. PATIENTS: 513 critically ill adult patients, 16 of whom were excluded because measurements on severity of illness scoring were not available. MAIN OUTCOME MEASURES: Age, severity of illness (determined with the acute physiology and chronic health evaluation (APACHE) II score), and diagnostic category on admission; deaths in the unit; and long term survival after discharge. Details of the survivors were sent to the Registrar General for Scotland, who issued copies of death certificates for the patients who had died between discharge and 1 January 1989. RESULTS: Of 497 patients, 119 (24%) died in the intensive therapy unit and 120 (24%) after discharge, leaving 258 (52%) who were still alive at two years. The median (APACHE II) score was 13 and about half of the patients were aged 55 years or more. A wide range of critical illnesses, except neurosurgical emergencies, were treated. Survival analysis showed that only 41 (34%) of 122 patients with an APACHE II score of greater than or equal to 20 were alive at one year (95% confidence interval 25 to 42) compared with 124 (80%) of 155 patients with a score of less than 10 (73 to 87). Of the 144 patients aged 65 or more, only 68 (47%) survived to one year (39 to 55) but 90 (83%) of the 109 patients aged between 18 and 34 survived a similar period (76 to 71). Mortality was also related to diagnostic category; 71% of trauma victims survived to one year compared with only 41% of those admitted with gastrointestinal pathology. Univariate analysis of the results showed that age, severity of illness, and diagnosis were all predictors of long term survival. Multivariate analysis, however, showed that only age and severity of illness were independent prognostic factors. CONCLUSIONS: Long term survival of patients treated in an intensive therapy unit is related to severity of illness and to age. The outcome from critical illness in the elderly population is poor.

Adolescent↗
PubMed1989

Total respiratory compliance during anaesthesia in infants and young children.

The multiple occlusion technique was used to study the effects of paralysis on ventilatory mechanics during anaesthesia. Total respiratory compliance (Crs) was measured during spontaneous breathing and following neuromuscular block with controlled ventilation in 23 infants. There was marked variation in response to paralysis: some infants demonstrated no change in Crs between the two states; others had values of Crs which were significantly higher during paralysis with controlled ventilation than during spontaneous breathing. A possible cause of these differences may be the type of controlled ventilation given during paralysis, with tidal volume directly influencing values of Crs obtained. The results of this study suggest that values of Crs obtained during spontaneous breathing and paralysis should not be used interchangeably until further studies have been performed to assess factors influencing Crs during controlled ventilation.

Anesthesia, General↗
PubMed1989

The effects of secondary transport on critically ill patients.

This study examined the effect of secondary transport on critically ill patients and the effectiveness of a regionally based intensive care service. Four hundred and ninety-five patients were studied retrospectively over a 2-year period. Eighty-two were transferred from peripheral hospitals in a mobile intensive care unit while the remaining 413 were admitted directly to the intensive therapy unit at the Western Infirmary, Glasgow. The severity of illness in both groups was assessed using the APACHE II scoring system. The transferred group were scored before and after the journey, while the directly admitted group were scored only on admission. The results show that the transferred patients exhibited a consistent cardiorespiratory response to transport irrespective of their severity of illness, and that the mortality in both groups of patients in the intensive therapy unit was not significantly different. The results also suggest that in the transferred group, the outcome is not only dependent on the severity of illness but also on other factors, such as the hospital from which the patient was referred and the duration of the pretransfer admission.

Adolescent↗
PubMed1989

Effect of vecuronium on atropine-induced changes in heart rate.

The effect of vecuronium on the heart rate response to atropine has been studied by comparing dose-response relationships in two groups of patients who underwent extracorporeal shock wave lithotripsy. One group received vecuronium (0.1 mg/kg) and the other acted as control. Incremental doses of atropine (1.8, 1.8, 3.6, 7.2 and 14.4 micrograms/kg) were administered and changes in heart rate recorded. No significant differences were observed between the two groups following each incremental dose of atropine.

Adult↗
PubMed1984

Fentanyl supplementation to inhalation anaesthesia.

In eight out of 15 healthy patients undergoing body surface surgery, the effect of a fentanyl infusion on a conventional thiopentone, nitrous oxide, oxygen and halothane anaesthetic was studied. The fentanyl infusion (2 micrograms/kg/hour) reduced the induction dose of thiopentone and caused marked respiratory depression with a reduction in the patients' response to surgery. The mean arterial pressures and pulse rates were not significantly different in each group throughout the course of the operation. The fentanyl made no difference to the patients' postoperative analgesic requirements or to their recovery in the first 24 hours.

Adjuvants, Anesthesia↗