Antibacterial effects in blood irradiated with a polychromatic device mediated through reactive oxygen species: possible involvement of haem.

The antibacterial effects of a polychromatic light device designed for intravenous application were assessed in vitro. Staphylococcus aureus, Klebsiella pneumoniae, or Escherichia coli were exposed to a 60-min sequential light cycle comprising 365, 530, and 630 nm wavelengths in circulated sheep blood. Bacteria were quantified by viable counting. The potential involvement of reactive oxygen species in the antibacterial effect was assessed using the antioxidant N-acetylcysteine-amide. A modified device was then used to determine the effects of the individual wavelengths. Exposure of blood to the standard wavelength sequence caused small (c. 0.5 Log 10 CFU) but statistically significant reductions in viable counts for all three bacteria, which were prevented by the addition of N-acetylcysteine-amide. Bacterial inactivation did not occur in blood-free medium, but supplementation with haem restored the moderate bactericidal effect. In single-wavelength experiments, bacterial inactivation occurred only with red (630 nm) light. Concentrations of reactive oxygen species were significantly higher under light stimulation than in unstimulated controls. In summary, exposure of bacteria within blood to a cycle of visible light wavelengths resulted in small but statistically significant bacterial inactivation apparently mediated by a 630 nm wavelength only, via reactive oxygen species possibly generated by excitation of haem groups.

Patient agitation and its management in adult critical care: A integrative review and narrative synthesis.

AIMS AND OBJECTIVE: To critically review the evidence relating to the management of agitation within the Adult Critical Care Unit environment and identify any risks and benefits of current management strategies. BACKGROUND: Admission to an Adult Critical Care Unit can be traumatic and potentially life altering for the patient. Patient agitation is common in Adult Critical Care Units and is associated with the potential for harm. Despite inherent safety risks, there is a paucity of evidence-based guidance underpinning the care of agitation in patients with critical illness. STUDY DESIGN: Integrative review and narrative synthesis. METHODS: A systematic procedure for searching and selecting the literature was followed and applied to databases including CINAHL, British Nursing Index, Cochrane Library, ProQuest, Ovid including EMBASE and MEDLINE. Selected manuscripts were analysed using a structured narrative review approach. RESULTS: A total of 208 papers were identified and following a systematic deselection process 24 original articles were included in the review. It was identified that agitation in the setting of Adult Critical Care Unit is associated with high-risk events such as unplanned removal of life-supporting devices. There were consistent links to sepsis, previous high alcohol intake and certain medications, which may increase the development of agitation. Prompt assessment and early liberation from mechanical ventilation was a major contributing factor in the reduction in agitation. Administration of antideliriogenic mediation may reduce the need for physical restraint. There was repeated uncertainty about the role of physical restraint in developing agitation and its effective management. CONCLUSIONS: Our review has shown that there is a dearth of research focusing on care of agitated patients in the Adult Critical Care Unit, despite this being a high-risk group. There are dilemmas for clinical teams about the effectiveness of applying physical and/or pharmacological restraint. The review has highlighted that the risk of self-extubation increases with the presence of agitation, reinforcing the need for constant clinical observation and vigilance. RELEVANCE TO CLINICAL PRACTICE: The importance of ensuring patients are re-orientated regularly and signs of agitation assessed and acted upon promptly is reiterated. Early identification of specific patient profiles such as those with previous high alcohol or psychoactive drug habit may enable more proactive management in agitation management rather than reactive. The prompt liberation from the restriction of ventilation and encouragement of family or loved ones involvement in care need to be considered.