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Biomedical subjects

I M Ledingham

Publications and source records attributed to I M Ledingham.

At least 37 records · Page 2Linked to original sources
PubMed1988

Endotoxaemia in multiple organ failure due to sepsis.

Patients with multiple organ failure secondary to intraabdominal sepsis are often blood culture negative despite exhibiting the features of septic shock. This study examined the possible central role of endotoxin in such patients. In 15 consecutive intensive care patients with the above clinical picture endotoxin was measured by a chromogenic limulus (LAL) assay; on admission and thereafter 4 hourly. Regular blood cultures and cultures of any primary septic focus were also performed and liver function was assessed by measurement of indocyanine-green clearance from plasma (ICGC). All 15 patients had significant endotoxaemia at least intermittently. No significant difference was observed between survivors (n = 5) and non-survivors (n = 10) in either initial or peak endotoxin levels, although the pattern of endotoxaemia differed with non-survivors exhibiting consistently high or steadily increasing levels. Of 5 patients with an intra-abdominal (I/A) septic focus only one had a positive blood culture while 5 of 10 patients with extra-abdominal (E/A) infection had positive cultures. Despite this the I/A group had higher initial and peak endotoxin levels. 3 patients with Gram-positive septicaemia had significant endotoxaemia in the absence of any gram-negative infection. Changes in ICGC appeared to be of useful prognostic significance. ICGC was significantly lower in the I/A group and in both groups there was a significant negative correlation between ICGC and the level of endotoxaemia. These results suggest that endotoxin may play a central role in the syndrome of multiple organ failure and further suggest that the endotoxin is endogenous (gut-derived) secondary to failure of hepatic filtration.

Adult↗
PubMed1987

Early emergency care study: the potential and benefits of advanced prehospital care.

Of 26358 patients taken by ambulance to the accident and emergency departments of two large hospitals, 1185 were admitted to resuscitation areas. The scope for ambulance staff to employ a range of advanced techniques at the scene of incidents was assessed by using information relating to the condition of patients when they were picked up by the ambulance and on admission, time in transit, details from hospital records, and outcome at three months. For non-survivors further assessment was made of the benefit, in terms of survival, which might have accrued had advanced techniques been used. The results of the assessment of benefit were compared with estimates of benefit from other studies. In cases of cardiopulmonary arrest the potential to save lives was less optimistic than earlier estimates, and in cases of trauma the potential to save lives was negligible.

Algorithms↗
PubMed1987

Propofol infusion for sedation in intensive care.

Ten patients, with a range of illness severity, received a continuous 8-hour infusion of undiluted propofol for sedation while undergoing mechanical ventilation in a general intensive care unit. The level of sedation was assessed hourly and measurements were made of haemodynamic, respiratory, haematological and biochemical variables. Sedation remained satisfactory in most patients throughout the study period, with only occasional alterations in infusion rate, and eight patients required further sedative therapy within 45 minutes of discontinuation of the propofol infusion. Arterial pressure tended to decrease from baseline values; mean and diastolic pressures demonstrated a significant decrease (p less than 0.05) at 4, 7 and 8 hours during the infusion. Adrenal steroidogenesis was not inhibited significantly. Propofol infusion proved to be a useful and readily controllable sedative agent, and discontinuation of the drug was followed by rapid recovery in most cases. The critically ill may be particularly sensitive to the cardiovascular depressant properties of the drug.

Aged↗
PubMed1987

Resuscitation in haemorrhagic shock--pulmonary and renal effects: an adverse effect of stabilised plasma protein solution on renal function?

In a model of severe canine haemorrhagic shock, greyhound dogs were randomly allocated to resuscitation with 0.9% saline, polygelin, hetastarch, or stabilised plasma protein solution (SPPS). Resuscitation was continued back to baseline pulmonary artery wedge pressure, and extravascular lung water (EVLW) and urine output were measured. EVLW following resuscitation was higher in the saline group than in any of the three colloid groups. Urine output following resuscitation was significantly lower in the SPPS group than in any other group. The results suggest that SPPS has an adverse effect on renal function in this model.

Animals↗
PubMed1986

Sedation in intensive care: morphine and renal function.

Intravenous morphine infusions have been administered to 12 critically-ill patients during controlled ventilation. Acute oliguric renal failure was present in 4 patients, who were treated with a combination of haemofiltration and haemodialysis. Severity of physiological disturbance was assessed using a modified APACHE Score, level of sedation by a linear-analogue scale, and blood morphine levels by high-pressure liquid chromatography. Morphine clearance was impaired in renal failure, and was dependent on haemofiltration volumes; accumulation of morphine did not occur during this form of treatment. Conscious level was clearly more closely related to the degree of physiological disturbance than blood morphine levels; and for a given blood morphine level, depression of consciousness was more pronounced the greater the degree of physiological disturbance. Use of a physiological sickness score may help to clarify some of the factors influencing cerebral function during critical illness. Careful clinical monitoring of level of sedation is important in patients with oliguric renal failure receiving morphine, and haemofiltration appears to reduce the risk of morphine accumulation in these patients.

Acute Kidney Injury↗
PubMed1985

Validation of a prognostic score in critically ill patients undergoing transport.

Fifty consecutive critically ill patients transported between hospitals by a mobile intensive care team were assessed prospectively using a modification of the acute physiology and chronic health evaluation (APACHE II) sickness scoring system. Assessments were made before and after resuscitation, on return to base, and after 24 hours of intensive care. No patient died during transport. Twenty two patients died subsequently in hospital and 28 survived to return home. The mean score for the non-survivors before resuscitation was 21.7 and for the survivors 12.2 (p less than 0.0005). Among the non-survivors there was a significant fall in score with resuscitation but this did not alter their subsequent outcome. Neither group deteriorated during transport. The sickness score is a powerful method for determining prognosis, and employed longitudinally it may be useful in the assessment of treatment. It has important implications for the administration and organisation of regional intensive care services.

Adult↗
PubMed1985

Increased vascular permeability: a major cause of hypoalbuminaemia in disease and injury.

The rate of loss of albumin to the tissue spaces (measured as transcapillary escape rate) rose by more than 300% in patients with septic shock, and the average increase within 7 h of cardiac surgery was 100%. The transcapillary escape rate in cachectic cancer patients was twice that of a group of healthy individuals. The rate of loss of albumin to the tissue spaces is normally 5%/h, which is more than 10 times the rates of synthesis and catabolism, and these large rate increases indicate that increased vascular permeability is an important cause of the lowered concentration of albumin commonly seen in acute and chronic disease.

Capillary Permeability↗
PubMed1984

Cellular defense in critically ill surgical patients.

Cell-mediated immunity was examined using 4 recall antigens in 102 critically ill surgical patients treated in an ICU. There were 4 (14%) deaths in 28 patients with positive reactions (R), compared to 33 (45%) deaths in 74 nonreactors (NR) (p less than .01). Thirty-seven of the patients were admitted after trauma, and mortality in this group was not significantly different between R and NR patients. Repeat testing in 40 NR patients who remained in the ICU for more than 7 days showed that 30 remained NR (70% mortality) and 10 became R (20% mortality, p less than .001). Peripheral blood lymphocytes from the patients showed a reduced response to concanavalin A, but a normal response to phytohemagglutinin and pokeweed mitogen. Mononuclear cells and granulocytes both showed a small increase in chemotactic response to casein, suggesting that the reduced response to skin testing may be partly due to defective T-cell function, rather than impaired phagocyte chemotaxis.

Adolescent↗
PubMed1984

Herpes simplex virus reactivation in surgical patients.

Evidence for oral shedding of herpes simplex virus Type I (HSV) indicating endogenous viral reactivation as a measure of depressed host defense was sought in 44 critically ill surgical patients. Eighteen (41%) of these showed persistent HSV shedding. None of 50 controls showed HSV shedding, but 4 (10%) of 42 patients undergoing elective surgery showed transient postoperative viral reactivation. In the critically ill surgical patients, oral HSV shedding was not related to outcome. However, failure to develop a rise in specific HSV antibody, in the presence of viral shedding, was associated with a high mortality. This is further evidence for impairment of both cell-mediated and humoral immunity in critically ill surgical patients.

Adolescent↗
PubMed1984

The relative prognostic value of lactate and haemodynamic measurements in early shock.

A prospective study was completed of 30 shocked patients admitted consecutively to an intensive therapy unit; the majority of the patients had shock of septic origin. Measurements were made of whole blood lactate together with mean arterial pressure, hourly urine volume and core: peripheral temperature difference at the start of treatment and 3 and 24 hours later. Serial lactate measurements were better at predicting outcome than single measurements. However, lactate measurements were much less valuable than serial measurements of the simple haemodynamic variables.

Blood Pressure↗
PubMed1984

Evaluation of a new fibre-optic pulmonary artery catheter in intensive care. A preliminary study.

We have assessed the performance of a new fibre-optic pulmonary artery catheter for the measurement of mixed venous oxygen saturation. The results obtained from this catheter compare well with those using standard techniques. Other information from the catheter allows oxygen consumption to be easily calculated and again the results obtained agree closely with those measured using standard techniques.

Adult↗
PubMed1984

Mortality amongst multiple trauma patients admitted to an intensive therapy unit.

A retrospective review of 428 severely injured patients admitted to an intensive therapy unit between 1969 and 1982 was performed. The patients' primary injuries were assessed using the injury severity score (ISS), and subsequent complications using the complications impact index and sepsis score. Between 1969 and 1980 mortality fluctuated between 19% and 29% but rose to 47% (p less than 0.05) during 1981-82 in spite of an unchanged ISS. The increased mortality was confined to ventilated patients surviving more than 5 days from injury and was associated with multiple organ failure and severe infection. The rapid and sustained increase in mortality could not be explained by any obvious change in severity of injury or referral pattern. The only deliberate change in management related to the combination of analgesic/sedative drugs used in ventilated patients. During 1979 to 1982 mortality was 28% in patients given morphine with or without benzodiazepines and 77% in those given morphine and etomidate (p less than 0.0005). After discontinuation of the latter regimen (May 1983) and resumption of the former analgesic/sedative combination, mortality fell to 25% (p less than 0.005). Possible mechanisms leading to increased mortality include adrenocortical insufficiency or depth of anaesthesia.

Adolescent↗