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Biomedical subjects

R R Macmillan

Publications and source records attributed to R R Macmillan.

9 recordsLinked to original sources

Critical care unit outbreak of Serratia liquefaciens from contaminated pressure monitoring equipment.

Between October and December 1999, Serratia liquefaciens was isolated from 11 patients in an adult critical care unit. One patient was infected on two separate occasions. In total, there were 10 positive blood cultures and five positive intravascular catheter tips. Eight cases were clinically infected, three were possibly infected and one was not. All patients with clinical isolates received appropriate empirical antibiotic treatment and responded well. Environmental investigation revealed S. liquefaciens in syringes and connector tubing used to calibrate the intravascular line pressure monitoring equipment of eight patients. Three of these patients also had clinical isolates of S. liquefaciens. Analysis by pulsed-field gel electrophoresis found clinical and environmental isolates to be of the same strain. The most likely mode of transmission was a non-sterile sphygmomanometer tip used daily for calibration. Inadequate microbiological sampling methods may have limited detection of S. liquefaciens. Several other examples of poor infection control techniques were identified during the outbreak, notably lapses in hand hygiene during intravascular pressure monitoring. It was also observed that unlabelled multidose heparin and insulin vials were shared between patients and personal hand creams were used by staff. However, these were not directly implicated in the outbreak. The outbreak ended when poor infection control practices were corrected. Calibration syringes and connector tubing were discarded after a single use. The sphygmomanometer was replaced by a pneumatic pressure transducer tester with connector tube and the frequency of calibration reduced to a single test following line insertion only. The non-disposable tube was disinfected with alcohol wipes between patients.

Adult↗

Providing psychological support for patients after critical illness.

The majority of patients have little or no memory of their stay in ICU or remember only pain, suctioning or lack of sleep. Dreams and nightmares while in the intensive care unit (ICU) and after discharge home have also been reported. The few studies investigating the longer-term psychological problems of critical illness point to a picture of social isolation with patients avoiding company and showing less affection to their partners. Our own experience, running a special outpatient clinic and following up patients by post, showed a picture of depression, anxiety, irritability and social isolation. This led to the setting up of an ICU staff-led support group for patients recovering from critical illness. This article outlines the possible problems and pitfalls of setting up and running a support group for patients recovering from critical illness. The type of patients suitable to attend such a group is examined. Two case histories give an illustration of the type of problems ICU patients experience during their recovery and how an informal support group can help. In addition to possible benefits to the patients, support groups can also give ICU staff a chance to understand the process of recovery from critical illness and to examine the effects on patients of their own practice. However, they must also have enough insight to know when a patient needs professional help; for example, a patient displaying symptoms of post-traumatic stress disorder should be referred, with their agreement, to a clinical psychologist.

Anxiety↗

Intestinal permeability in the critically ill.

Alterations in intestinal permeability reflect one component of intestinal epithelial barrier function. The objective of this study was to assess the degree of derangement of intestinal permeability in critically ill patients and to investigate the relationship of this to markers of disease severity and sepsis. Sixteen patients admitted to the intensive care unit for a variety of problems were studied with the severity of illness and degree of sepsis recorded daily. A differential sugar absorption test, using lactulose and mannitol as markers, was performed, and in 10 patients this was repeated after an interval of between 4-11 days. The use of the lactulose/mannitol (L/M) ratio corrects for variables unrelated to permeability such as gastric emptying. The L/M ratio was significantly higher in patients (median 0.98) compared to normal controls (median 0.008). The ratios showed no relation to disease severity or sepsis. These results establish that increased intestinal permeability occurs in the general ICU patient but that it is not uniquely related to sepsis. The extent of this abnormality suggests that further study is required to show the various influences on this process.

Adult↗

Electromyographic assessment of neuromuscular blockade induced by atracurium.

The effects of atracurium besylate 0.3 mg kg-1 or 0.6 mg kg-1 on neuromuscular function were assessed by electromyography in 11 normal subjects, using successive trains of four supramaximal stimuli. After the induction of anaesthesia, the relation between the reduction in the amplitude of the compound muscle action potential and decrement was studied during the onset and recovery of nondepolarizing blockade. During induction, the decrease in the amplitude of the initial compound muscle action potential was usually greater than decrement, and resembled the pattern observed with pancuronium. In contrast, during recovery from myoneural blockade, decrement was invariably greater than the reduction in the amplitude of the action potential. It was considered that these effects were consistent with the action of atracurium on more than one group of receptors at the neuromuscular junction. The effects of atracurium were rapidly antagonized by neostigmine, and supplementary doses of the drug showed no evidence of cumulation.

Action Potentials↗