Aust Crit Care
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The carbonic acid/bicarbonate system, as defined by the Henderson-Hasselbach (H-H) equation, has traditionally formed the centrepiece of the presentation of acid/base physiology in nursing education. However, an alternative approach to describe acid/base physiology was proposed by Peter Stewart in 1983. Stewart determined, using the physiochemical principles of dissociation equilibrium, electroneutrality and conservation of mass, that hydrogen ion concentration [H+] was dependent upon the difference between the concentrations of strong cations and strong anions in a solution (the strong ion difference or SID), concentration of weak acid anions, and the partial pressure of carbon dioxide in plasma. ⋯ An analysis of the complex acid/base derangements commonly seen in the critically ill can be achieved using this approach. The acid/base consequences of vomiting, gastric aspiration, diarrhoea, diuretic therapy, the infusion of large volumes of normal saline, the contribution of lactate, and the effects of methanol and ethylene glycol poisoning can all be more readily understood considering Stewart's explanation of acid/base balance. This paper outlines this alternative approach and provides some examples for the intensive care setting.
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Advances in medical practice and technology and the success of organ transplantation over the past 2 decades have resulted in an increased demand for organ donors. However, the health care community and organ procurement organisations (OPO) are faced with a worldwide shortage of donor organs. The non-consent of families is the most common reason that organs of medically suitable potential donors are not recovered. ⋯ The literature review indicates that the significant factors associated with denial of consent include: the misunderstanding of brain death; cultural beliefs; the specific timing of the request; the setting in which the request is made; the approach of the individual making the request; and characteristics of the deceased. Organ donation and transplantation rates could be increased by the joint involvement of medical, nursing and OPO personnel to enhance the quality of hospital care and to ensure that requests for donation are handled in a way that meets the family's informational and emotional needs. Increased consent rates have the potential to save lives and improve the quality of life for organ recipients.
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This paper reports on a pilot study that focused on the feasibility of conducting longitudinal research on the health status of intensive care unit (ICU) survivors. Twenty patients completed a short ICU specific health status survey while in ICU and then were invited to complete the same survey--with the addition of the Medical Outcome Study Short Form-36 (SF-36) health status survey--at 6 and 12 months after their hospital discharge. While the patients were in the ICU, 20 family members completed the same survey on the patients' behalf as proxy respondents. ⋯ Total attrition at 12 months was 40 per cent. Using the results of the SF-36, sample size estimates were conducted in preparation for a larger study. It was concluded that it is feasible to conduct longitudinal research on ICU survivors but proxy responses should not be used indiscriminately.
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The purpose of this study is to examine whether a relationship exists between arterial and end-tidal carbon dioxide tension (PaCO2 and PETCO2 respectively) in patients admitted to intensive care units (ICUs), and what the implications it has for nursing care. PaCO2 and PETCO2 are indicators of ventilatory adequacy which is an important aspect of respiratory function. ⋯ A population of 30 intubated patients had 214 simultaneous measurements of PaCO2 and PETCO2 taken over a period of 10 months. The findings indicate that, despite strong significant correlations, PETCO2 cannot be used safely as a substitute for PaCO2 as the arterial/end-tidal carbon dioxide gradient is not constant, nor does capnography provide a consistently reliable indicator of PaCO2.