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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
PubMed2001

Adaptive lung ventilation.

Adaptive lung ventilation (ALV) is a method of closed-loop mechanical ventilation analogous to modern closed-loop technology in aviation such as the autopilot and automatic landing system. The algorithm of the controller of ALV is designed to automatically provide pressure-controlled synchronized intermittent mandatory ventilation (P-SIMV) and weaning as individually required in any clinical situation. The synchronized pressure limited breaths constantly adapt to the patient requirements to encourage optimal alveolar ventilation with minimal adverse physiological disturbance and timely weaning. The ease of application, efficiency, and safety of the first ALV controllers have been demonstrated in lung models, in patients with normal lungs undergoing general anesthesia, in patients requiring unusual positioning, in transition to and from one-lung anesthesia, and in long-term ventilation of patients with various lung pathologies and in weaning patients who have restrictive or obstructive pulmonary disease. Prospective comparative studies of ALV versus other currently used manually selected modes of mechanical ventilation, such as the one reported in this article, should confirm the safety and identify the benefits of this form of advanced closed-loop mechanical ventilation technology.

Algorithms↗
PubMed2001

Plasmapheresis for thrombotic thrombocytopenic purpura following bone marrow transplantation.

Recognition of thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) following bone marrow transplantation (BMT) has increased in recent years. The use of plasma exchange has greatly improved the outlook of de novo TTP. Fewer data are available on its use in post-BMT TTP but small uncontrolled series showed poor results with low response rates. We present here a case of a young patient who developed manifestations of TTP 10 months after BMT with complete recovery following treatment with plasma exchange for 1 month. This case suggests that plasma exchange could be life saving and should be tried in every patient with post-BMT TTP.

Adult↗
PubMed1997

Severe necrotizing pancreatitis caused by organophosphate poisoning.

Pancreatitis secondary to organophosphate insecticide toxicity is rare and is believed to follow a subclinical and uneventful course. We report two cases of severe acute pancreatitis complicated by pancreatic necrosis and retroperitoneal sepsis in which the diagnosis was obscured by the systemic effects of organophosphate toxicity. Awareness of this complication should prompt earlier investigation because early diagnosis coupled with timely therapeutic measures may improve patient prognosis.

Adult↗
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↗