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Biomedical subjects

R D Griffiths

Publications and source records attributed to R D Griffiths.

At least 19 recordsLinked to original sources

Nutrition support for patients in the intensive care unit.

Enteral nutrition (EN) is the mainstay of nutrition delivery within intensive care seeking to capitalise on its benefits for the gastrointestinal tract and associated immune system, but this has brought new challenges in delivery to the sick. The hoped for benefit has led to the mistaken belief by some that parenteral nutrition (PN) is no longer required. However, a greater appreciation of the risks of EN delivery in the sick patient combined with improvements in PN formulation and use help explain why PN is not as risky as some have believed. Real outcome benefits have been described with the new glutamine containing PN formulations. PN remains important in the presence of gastrointestinal feed intolerance or failure.

Combined Modality Therapy↗

Effect of vitamin C supplements on antioxidant defence and stress proteins in human lymphocytes and skeletal muscle.

Oxidative stress induces adaptations in the expression of protective enzymes and heat shock proteins (HSPs) in a variety of tissues. We have examined the possibility that supplementation of subjects with the nutritional antioxidant, vitamin C, influences the ability of lymphocytes to express protective enzymes and HSPs following exposure to an exogenous oxidant and the response of skeletal muscle to the physiological oxidative stress that occurs during exercise in vivo. Our hypothesis was that an elevation of tissue vitamin C content would reduce oxidant-induced expression of protective enzymes and HSP content. Lymphocytes from non-supplemented subjects responded to hydrogen peroxide with increased activity of superoxide dismutase (SOD) and catalase, and HSP60 and HSP70 content over 48 h. Vitamin C supplementation at a dose of 500 mg day-1 for 8 weeks was found to increase the serum vitamin C concentration by ~50 %. Lymphocytes from vitamin C-supplemented subjects had increased baseline SOD and catalase activities and an elevated HSP60 content. The SOD and catalase activities and the HSP60 and HSP70 content of lymphocytes from supplemented subjects did not increase significantly in response to hydrogen peroxide. In non-supplemented subjects, a single period of cycle ergometry was found to significantly increase the HSP70 content of the vastus lateralis. Following vitamin C supplementation, the HSP70 content of the muscle was increased at baseline with no further increase following exercise. We conclude that, in vitamin C-supplemented subjects, adaptive responses to oxidants are attenuated, but that this may reflect an increased baseline expression of potential protective systems against oxidative stress (SOD, catalase and HSPs).

Adult↗

Measurement of free radical production by in vivo microdialysis during ischemia/reperfusion injury to skeletal muscle.

Microdialysis techniques have been used to detect hydroxyl radical and superoxide release into the interstitial space of anaesthetized rat anterior tibialis muscles during a period of prolonged (4 h) limb ischemia and subsequent reperfusion. Data indicate that reperfusion of the ischemic skeletal muscle was associated with a large increase in hydroxyl radical activity in the interstitial space, which may contribute to the significant oxidation of muscle glutathione, protein thiols, and lipids also seen in this model. No evidence for release of superoxide into the interstitial space was found during reperfusion, although this was observed during electrically stimulated contractile activity of the rat limb muscle. These data imply that therapeutic approaches aimed at reduction of hydroxyl radical generation in the interstitial fluid are more likely to be beneficial in reduction of skeletal muscle reperfusion injury than approaches designed to scavenge superoxide radicals.

Animals↗

Smoking cessation through comprehensive critical care.

There has been little research on smoking cessation after critical illness. Smokers make up a high percentage of patients admitted to intensive care (ICU) and stopping smoking is one message that should be clearly given to recovering patients. The recovery period provides an important opportunity for patients to quit smoking as the period of sedation and ventilation allows patients to start nicotine withdrawal. Smoking cessation advice was included in a 6-week self-help ICU rehabilitation package comprising information and an exercise programme. Recovering ICU patients were randomised to receive either the routine follow-up of ward visits and ICU clinic appointments or routine follow-up plus the ICU rehabilitation package. Twenty out of thirty-one intervention patients and 16/30 control patients were smokers pre-ICU admission. At the 6-month follow-up, previous smokers given the rehabilitation package had a relative risk reduction for smoking of 89% (CI 98%-36%). Smoking cessation after critical illness is aided by the provision of a rehabilitation programme.

Adolescent↗

The evidence for glutamine use in the critically-ill.

Research into the metabolic role of glutamine in trauma and sepsis brings evidence to suggest a conditional deficiency occurs because increased and altered tissue demands exceed endogenous production. Such a deficiency has functional implications, and the restorative provision of parenteral glutamine has been shown to offer improved clinical outcomes in a variety of conditions. In the critically-ill it is associated with improvements in immune function, and improved survival from infection leading to an overall improved outcome.

Critical Illness↗

Memory, delusions, and the development of acute posttraumatic stress disorder-related symptoms after intensive care.

OBJECTIVE: To examine prospectively the relationship between memories of intensive care (ICU) and levels of anxiety after ICU discharge, the stability of these memories with time, and their relationship to the development of acute posttraumatic stress disorder (PTSD)-related symptoms. DESIGN: Case series cohort assessed by interview at 2 and 8 wks after ICU discharge. SETTING: District general hospital (serving a population of 350,000) general intensive care unit. PATIENTS: Memories of ICU and anxiety levels were studied in 45 patients after ICU discharge. Thirty patients were examined again at 8 wks to assess memory stability and development of acute PTSD-related symptoms. MEASUREMENTS AND MAIN RESULTS: Standardized interviews and questionnaires were used to assess memory for ICU, anxiety, and depression 2 wks after ICU discharge. In addition, PTSD-related symptoms and panic were assessed 8 wks after ICU discharge. A total of 33 of 45 patients had delusional memories from ICU at 2 wks; nine of the patients with delusional memories had no factual memories, and these patients had higher anxiety levels 2 wks after ICU discharge (p < .0001). Thirty patients had paired assessments at 2 and 8 wks. Those patients who had no factual recall of ICU but had delusional memories at 2 wks scored highly for PTSD-related symptoms and panic attacks at 8 wks (p = .023 and .014, respectively). The only predictors of possible acute PTSD-related symptoms at the 8-wk assessment were trait anxiety (p = .006) and having delusional memories without recall of factual events in the ICU at 2 wks (p < .0001). Only delusional memories were retained over time, whereas the recall of factual events in the ICU declined. CONCLUSIONS: We propose that the development of acute PTSD-related symptoms may be related more to recall of delusions alone. This study suggests that even relatively unpleasant memories for real events during critical illness may give some protection from anxiety and the later development of PTSD-related symptoms when memories of delusions are prominent.

Acute Disease↗

Contractile activity-induced oxidative stress: cellular origin and adaptive responses.

Previous studies have reported that oxidizing free radical species are generated during exercise, and there has been considerable interest in the potential effects of these on exercising tissues. We hypothesized that contracting skeletal muscle was a major source of oxidizing free radical species and that untrained skeletal muscle would adapt to the oxidative stress of a single short period of contractile activity by upregulation of the activity of cytoprotective proteins in the absence of overt cellular damage. Fifteen minutes of aerobic contractile activity was found to induce a rapid release of superoxide anions from mouse skeletal muscle in vivo, and studies with contracting cultured skeletal muscle myotubes confirmed that this was due to release from myocytes rather than other cell types present within muscle tissue in vivo. This increased oxidant production caused a rapid, transient reduction in muscle protein thiol content, followed by increases in the activities of superoxide dismutase and catalase and in content of heat shock proteins. These changes occurred in the absence of overt damage to the muscle cells.

Adaptation, Physiological↗

Is tap water a safe alternative to normal saline for wound irrigation in the community setting?

OBJECTIVE: This double-blind randomised controlled trial compared the effects of tap water and normal saline on the healing and infection rates of acute and chronic wounds. METHOD: The trial was conducted in two metropolitan community health centres in New South Wales, Australia. Thirty-five patients with 49 acute or chronic wounds were randomised to receive wound irrigation with either normal saline or tap water. RESULTS: Statistical analysis demonstrated there was no significant difference between the infection and healing rates in wounds irrigated with normal saline or tap water. CONCLUSION: Although the small sample size is a limitation of this study, the researchers conclude that drinkable tap water appears to provide a safe alternative to normal saline for wound cleansing and may be preferred by some patients.

Acute Disease↗

Disturbed memory and amnesia related to intensive care.

Patients, when admitted to an intensive care unit (ICU), have one thing in common: their illness is life-threatening. Patients may remain on ICU in a critical condition, needing support with their breathing, circulation, and/or kidneys for varying lengths of time, from days to weeks. During that time the patients will receive sedative and analgesic drugs to ensure compliance with artificial ventilation. Patients recovering from critical illness frequently have little or no recall of their period in ICU, or remember nightmare, hallucinations, or paranoid delusions. The nature, extent and reason for these difficulties, have been under-reported and consequently our purpose was to conduct a review of memory problems experienced by ICU patients. A systematic literature review of computer databases (Medline, PsycLit, and CINAHL) identified 25 relevant papers. In addition, other relevant articles were obtained, citation lists and associated articles retrieved. Due to lack of research on processes underlying memory problems in ICU patients all articles that introduced an insight into possible mechanisms were included in the review. There seem to be two possible processes contributing to memory problems in ICU patients. First the illness and treatment may have a general dampening effect on memory. Delirium and sleep disturbance are both common in ICU patients. Delirium can result in a profound amnesia for the period of confusion. Sleep deprivation exacerbates the confusional state. Slow wave sleep is important for the consolidation of episodic memories. Treatment administered to patients in ICU can have effects on memory. Opiates, benzodiazepines, sedative drugs such as propofol, adrenaline, and corticosteroids can all influence memory. In addition, the withdrawal of drugs, such as benzodiazepines, can cause profound withdrawal reactions, which may contribute to delirium. Second, we hypothesise that there is a process that affects memory negatively for external events but enhances memory for internal events. The physical constraints and social isolation experienced by ICU patients and the life-threatening nature of the illness may increase the experience of hypnagogic hallucinations. Attentional shift during hypnagogic images from external stimuli to internally generated images would explain why ICU patients have such poor recall of external ICU events, but can clearly remember hallucinations and nightmares. Patients describe these memories as being very vivid and this is explored in terms of flashbulb memory formation. The absence of memories for real events on ICU can result in ICU patients remembering paranoid delusions of staff trying to kill them, with little information to reject these vivid memories as unreal. This has implications for patients' future psychological health.

Critical Care↗

A case of Capgras delusion following critical illness.

Hallucinations and paranoid delusions are recognised complications of critical illness. However, the occurrence of Capgras syndrome, in response to critical illness, where patients are convinced that doubles have replaced close family has not been described in the literature. There have been isolated case histories in the literature in response to medical procedures or illness but mostly in patients suffering from schizophrenia. A 42 year old woman was admitted to the intensive care unit (ICU) with pneumonia, following extensive surgery for a squamous cell carcinoma, secondary to Crohns disease. She had no history of previous head injury, cerebro-vascular problems or psychiatric disorder. She reported having memories of all her family, with the exception of her mother, being replaced by aliens while she was on the ICU. The delusion was only diagnosed once it had resolved and the patient was able to talk, and this highlights the difficulty of diagnosing delusions while patients are still intubated and unable to verbalise their concerns. It has been suggested that a defect in the ability to recognise the emotional significance of the face lies at the root of Capgras syndrome.

Adult↗