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Biomedical subjects

D M Linton

Publications and source records attributed to D M Linton.

At least 19 recordsLinked to original sources
PubMed1994

Automatic weaning from mechanical ventilation using an adaptive lung ventilation controller.

STUDY OBJECTIVE: To evaluate a new method of closed-loop mechanical ventilation using an adaptive lung ventilation (ALV) controller in patients with different pathologic causes of respiratory failure at a time when they first met standard weaning criteria. STUDY DESIGN: Prospective, open, selected case study. SETTING: The 10-bed, multidisciplinary respiratory intensive care unit at Groote Schuur hospital, which is a teaching unit of the University of Cape Town. PATIENTS: Twenty-seven patients (9 patients in each of 3 groups: normal lungs, parenchymal lung disease, and COPD) who required prolonged mechanical ventilation and who met standard weaning criteria were included. Our institutional committee for ethical research approved the study and informed consent was obtained. INTERVENTIONS: The patients were mechanically ventilated and had daily measurements of vital capacity, respiratory rate, and arterial blood gas analysis until they met standard weaning criteria. On the day that each patient met the weaning criteria, a closed loop control algorithm providing ALV was implemented on a modified ventilator (Hamilton AMADEUS) with a PC-based lung function analyzer. After measuring gross alveolar ventilation, patients were placed in ALV and ventilatory and hemodynamic parameters were measured at baseline, 5 min, 30 min, and 2 h. Pertinent parameters measured included airway pressures, pressure support levels, respiratory rates, rapid shallow breathing indices, airway resistance indices, and patient respiratory drive and work indices. MEASUREMENTS AND RESULTS: In 22 patients, ALV reduced pressure support to 5 cm H2O and an intermittent mandatory ventilation rate of 4 breaths/min within 30 min, and all but 1 of these patients were successfully extubated within 24 h. In four patients, pressure support was maintained by ALV at a mean level of 14.6 cm H2O +/- for 2 h and these patients were recorded as having failed to wean. There was a measurable difference in an index of airway resistance relative to muscular activity between the successfully weaned and failed wean patients with COPD during the attempted wean by the ALV controller. CONCLUSIONS: ALV will provide a safe, efficient wean and will respond immediately to inadequate ventilation in patients when standard weaning criteria are met.

Adult↗
PubMed1994

Fatal Capnocytophaga canimorsus (DF-2) septicaemia. A case report.

A 45-year-old man died 2 months after being bitten on the hand by a dog. He developed the rare but characteristic clinical picture of fulminant septicaemia and peripheral gangrene caused by a Gram-negative bacillus, Capnocytophaga canimorsus, previously known as dysgonic fermenter type 2 (DF-2), which is an occasional commensal in the oral flora of dogs and cats. This disease must be anticipated and dog bites appropriately managed to avoid the mortality associated with infection by this micro-organism. Initial treatment includes appropriate prophylactic antibiotics and debridement, while early exchange transfusion and emergency amputation may be of value in fulminant cases.

Animals↗
PubMed1992

Metabolic requirements in tetanus.

OBJECTIVE: To measure the metabolic requirements of patients with severe tetanus who require mechanical ventilation. DESIGN: Prospective, consecutive, open study using routine monitoring. SETTING: A multidisciplinary ICU in a large teaching hospital. PATIENTS: Five consecutive patients (age range 30 to 54 yrs) with severe tetanus. Four patients had clinical evidence of sympathetic nervous system overactivity. INTERVENTIONS: All patients were mechanically ventilated and appropriately treated for severe tetanus. Sympathetic nervous system overactivity was reduced by the administration of sedatives. MEASUREMENTS AND MAIN RESULTS: Measurements of metabolic rates were made using an indirect calorimetry device. Each of the five patients had three 8-hr periods of continuous metabolic monitoring for each of three levels of daily enteral nutritional support. The measured metabolic rates varied from 1310 to 2050 kcal/24 hrs (predicted 1280 to 1770 kcal/24 hrs). The variations from predicted basal metabolic rates varied from -6.3% to +10.5%. CONCLUSIONS: The measured metabolic rates of patients with severe tetanus who are appropriately sedated are relatively constant and are within 10.5% of the predicted basal metabolic rates.

Adult↗
PubMed1991

Intensive care management of community-acquired Klebsiella pneumoniae.

The clinical features of 18 patients with Klebsiella pneumoniae requiring intensive care unit (ICU) management are presented. All patients required ventilatory support; 17 were given constant positive pressure ventilation and 10 required greater than 10 cm positive end expiratory pressure. The clinical picture was characteristic: pre-existing medical disease, clinical features of severe pneumonia and copious purulent bronchial secretions, Gram--ve organisms on Gram's stain and lobar consolidation on the chest radiograph were common. Septicaemic shock, confusion and uncompensated metabolic acidosis were the presenting clinical features predicting a poor outcome. Antimicrobial chemotherapy, that combined an aminoglycoside and a third generation cephalosporin to ensure adequate early antibiotic serum levels, may help to improve the prognosis.

Acidosis↗
PubMed1991

Midazolam-induced benzodiazepine withdrawal syndrome.

A case history of a patient who developed severe anxiety and agitation on two occasions after discontinuation of a midazolam infusion is presented. The withdrawal symptoms interfered with effective mechanical ventilation and the patient required the reintroduction of a long-acting benzodiazepine to treat the withdrawal state and to facilitate weaning from mechanical ventilation.

Akathisia, Drug-Induced↗
PubMed1990

Monitoring in motion. An update on the Air Ambulance Service of the South African Red Cross Society (Cape Region).

Since 1966, when 40 patients were transported in a single-engined light aircraft in its first year of service, the Air Ambulance Service of the Cape Region of the South African Red Cross Society has continued to grow annually, providing the people of southern Africa with a remarkable and, in its many ways, unique service. More than 3,300 patients have been transported on more than 2,500 flights in the past 23 years. In June 1988, a Cessna Citation jet aircraft was taken into service and, by 20 January 1989, had already transported more than 148 patients on 102 flights. This aircraft was equipped in Cape Town and has sophisticated life support and monitoring equipment, which enables critically ill patients to be transported over long distances in safety.

Aircraft↗
PubMed1990

Myasthenia gravis.

Myasthenia Gravis is a disorder of neuromuscular function resulting from an immunologically based premature destruction of acetylcholine receptors. The disease is characterized clinically by variable weakness accentuated by repetitive muscular activity and usually responding to the administration of acetylcholinesterase inhibitors. Myasthenia Gravis is a complex disease and requires understanding of the many facets of its natural history and immunological basis to ensure optimal individual patient management. The long-term goal is control of the immunological imbalance; treatment regimens include thymectomy, corticosteroids, azathioprine, and plasmapheresis. The common use of acetylcholinesterase inhibitors provides symptomatic relief during variable daily muscular activity. Disability due to myasthenia gravis is to a large extent reversible and death is preventable. Early recognition of myasthenia gravis and appropriate treatment are often rewarded by remission that may be permanent.

Diagnosis, Differential↗
PubMed1989

Systems for scoring severity of illness in intensive care.

Severity of illness scoring systems are increasingly being used by many intensive care units to predict mortality and to compare results and different therapies. A study was undertaken to evaluate three of these systems--therapeutic intervention scoring system (TISS), acute physiology and chronic health evaluation (APACHE II), and organ failure--in a 2-year prospective analysis in a multidisciplinary intensive care unit. A total of 728 patients with a wide variety of diseases were entered into the study. The relationship between score and mortality in all patients and in specific groups was investigated. The APACHE II system is likely to be the most useful in comparing different therapies and intensive care units, while the organ failure system was more accurate in predicting outcome. No system was precise enough in its predictive powers to make decisions to deny or terminate treatment.

Adolescent↗
PubMed1989

Evaluation of the efficacy and tolerance of intravenously administered imipenem/cilastatin in the treatment of septicaemia.

In an open study to determine the efficacy, safety and tolerance of intravenously administered imipenem/cilastatin (Tienam 500; Logos) in the treatment of septicaemia, 34 patients were given this thienamycin antibiotic in doses ranging from 1.5 g to 2 g daily for an average of 8.6 days (range 3-44 days). Based on clinical assessment, the study drug appeared to be effective in treating the septicaemia in 28 out of 34 patients and bacteriologically assessed eradication of the isolated pathogen was proven in 24 out of 34 patients. The drug appeared to be well tolerated in all but 4 patients, 3 of whom developed mild phlebitis and 1 a skin rash.

Adolescent↗
PubMed1989

Mandatory minute volume weaning in patients with pulmonary pathology.

This study evaluates mandatory minute volume (MMV) weaning in patients with pulmonary pathology. When weaning criteria were fulfilled, 22 patients were randomised to MMV and 18 to a control intermittent mandatory ventilation (IMV) group. With IMV weaning the ventilator rate was decreased by two breaths per minute at 3-4 hourly intervals during daylight hours. In the MMV group a target of 75% of the ventilator minute volume was set. All weans were considered complete four hours after the cessation of mechanical support, and were deemed successful if no further ventilation was required. The success rate was 86% in the IMV and 89% in the MMV group. MMV weaning was rapid (4.75 + 1.5 hrs) and proved less demanding on the ICU staff by providing a safe trial of spontaneous respiration, while retaining the facility for partial ventilation.

Adult↗
PubMed1988

Imipenem/cilastatin in the treatment of severe nosocomial pneumonia.

Imipenem/cilastatin (Tienam 500; Logos) 1 g, administered intravenously every 8 hours, was evaluated in an open clinical trial in 35 patients with severe nosocomial pneumonia. In 84.4% of cases there was a favourable clinical response; microbiological success was achieved in 63.3% and partial success in 20% of patients. The majority of Gram-negative and Gram positive organisms were sensitive to imipenem, including those resistant to the aminoglycosides. Although colonisation was frequent, superinfection was uncommon. Imipenem was well tolerated in these critically ill patients, many of whom had renal and other organ failure. The wide spectrum of antimicrobial activity and minimal side-effects made it a useful agent in patients with severe nosocomial pneumonia.

Adolescent↗