The influence of hyperchloraemia on acid base interpretation in diabetic ketoacidosis

Objectives During the acute treatment of diabetic ketoacidosis we (a) determined the temporal incidence of hyperchloraemia, and (b) quantified the influence of hyperchloraemia on interpretation of common blood gas derived acid base parameters, namely base deficit and bicarbonate. Designand setting Retrospective chart review in two regional paediatric intensive care units. Measurements and Results Stewart's physicochemical theory was used to develop regression equations quantifying the acidifying effect of hyperchloraemia on both base deficit and bicarbonate. These were then applied retrospectively to blood chemistry results from 18 children (median age 12.7 years, weight 43 kg) with diabetic ketoacidosis. Plasma ketonaemia was estimated using the albumin-corrected anion gap. The incidence of hyperchloraemia, as documented by a ratio of plasma chloride to sodium of greater than 0.79, increased from 6% at admission to 94% after 20 h of treatment. Correction for chloride produced a dramatic improvement in the relationship between changes in the anion gap vs. both base deficit (from R ² = 0.55 to R ² = 0.95) and bicarbonate (from R ² = 0.51 to R ² = 0.96) during treatment. After 20 h of treatment the mean base deficit had decreased from 24.7 mmol/l to 10.0 mmol/l however, the proportion that was due to hyperchloraemia increased from 2% to 98%. Conclusions It is now possible using a simple correction factor to quantify the confounding effect of hyperchloraemia on both base deficit and bicarbonate in diabetic ketoacidosis. This bedside tool may be a useful adjunct to guide therapeutic interventions.     

The context, measures and outcomes of psychosocial care interventions in long-term health care for older people

This paper examines the psychosocial dimensions of long-term care with reference to the new International Classification of Functioning, Disability and Handicap (ICIDH 2) and to research conducted in Hong Kong. It also draws on selected international literature about older people. It discusses the different ways in which information can be gained about the personal, social and emotional processes of rehabilitation that influence outcomes and raises methodological questions about the study of interventions. Outcomes that are sensitive to psychosocial interventions and that take account of the elderly person's own perspective are identified as important challenges for nurses and other professionals in the multidisciplinary team, in order to respond to an individualized approach to long-term care. It is concluded that gaining a better understanding of the psychosocial dimensions of long-term care will enhance professional practice and benefit older people and their carers.     

Electrical stimulation of the ventral tegmental area evokes sleep‐like state transitions under urethane anaesthesia in the rat medial prefrontal cortex via dopamine D1‐like receptors

The role of dopamine in regulating sleep‐state transitions during, both natural sleep and under anaesthesia, is still unclear. Recording in vivo in the rat mPFC under urethane anaesthesia, we observed predominantly slow wave activity (SWA) of <1 Hz in the local field potential interrupted by occasional spontaneous transitions to a low‐amplitude‐fast (LAF) pattern of activity. During periods of SWA, transitions to LAF activity could be rapidly and consistently evoked by electrical stimulation of the ventral tegmental area (VTA). Spontaneous LAF activity, and that evoked by stimulation of the VTA, consisted of fast oscillations similar to those seen in the rapid eye movement (REM)‐like sleep state. Spontaneous and VTA stimulation‐evoked LAF activity occurred simultaneously along the dorsoventral extent of all mPFC subregions. Evoked LAF activity depended on VTA stimulation current and could be elicited using either regular (25–50 Hz) or burst stimulation patterns and was reproducible upon repeated stimulation. Simultaneous extracellular single‐unit recordings showed that during SWA, presumed pyramidal cells fired phasically and almost exclusively on the Up state, while during both spontaneous and VTA‐evoked LAF activity, they fired tonically. The transition to LAF activity evoked by VTA stimulation depended on dopamine D₁‐like receptor activation as it was almost completely blocked by systemic administration of the D₁‐like receptor antagonist SCH23390. Overall, our data demonstrate that activation of dopamine D₁‐like receptors in the mPFC is important for regulating sleep‐like state transitions.