answers 34 by sandeshbhat


									CLINICAL SCENARIO Intensive Care Nursing (2nd Edition) Ed P. Woodrow Chapter 34: Fluid Management Mr Kenneth McDowall is a 48-year-old known smoker, who had spent an afternoon drinking alcohol and watching sports with friends. While preparing an outdoor barbeque later that day, he collapsed onto the grill, which overturned dropping hot charcoal onto Mr McDowall. He sustained extensive burns down the right side of his head and body. Mr McDowall was admitted unconscious, vasoconstricted, diaphoretic with full thickness burns. His ECG on admission revealed large left ventricular infarcted area. Other results included tachycardia (130 beats/min), BP 100/78 mmHg, CVP 10 mmHg, tachypnoeic (26 breaths/min) arterial blood gas showed good oxygenation with uncompensated respiratory acidosis, Na+ 148 mmol/L, K+ 4.5 mmol/L, blood glucose 12 mmol/L. He is cannulated with one peripheral cannula and quad CVC in left jugular vein. Q1. Identify the signs which indicate Mr McDowall needs fluid management.

Q2. Select an appropriate crystalloid & colloid to infuse. Justify this choice, the intravenous route, rate of infusion and list expected effects (include benefits and limitations). Q3. Reflect on how fluid challenges are administered in your clinical area (type & volume of fluid, rate and route, use of dynamic indicators or a protocol) A1. Mr McDowell’s history and observations suggest dehydration. Alcohol inhibits ADH, promotes diuresis and hypotonic dehydration. Extensive burns will cause fluid exudation and dehydration. Diaphoresis (sweating) will increase his insensible fluid loss and cause isotonic dehydration. Tachycardia, narrow pulse pressures and vasoconstriction indicate hypovolaemia despite high CVP. His increased CVP may indicate right ventricular failure secondary to left heart failure. High respiratory rate will increase fluid loss. The high plasma sodium concentrations may be from vascular dehydration and haemoconcentration. Blood glucose above the renal threshold of 10 mmol/L will cause an osmotic diuresis (glycosuria) and further dehydrate Mr McDowall. A2. Select a balanced crystalloid solution such as Compound Sodium Lactate (Hartmann’s solution). This has less sodium than Sodium Chloride. It is isotonic with electrolytes in similar concentration as plasma (but no phosphate). There is no glucose in this solution. Compound Sodium Lactate is useful in treating hypovolaemia, burns and mild metabolic acidosis. However, it may contribute to dependant oedema. The crystalloid should be administered via a volumetric pump to ensure accuracy and at a rate of 1 to 1.5 mls/kg/h (dependant on local unit policy, some ICU’s prefer ‘wet’ patients others prefer ‘dry’ e.g. cardiac ICU’s). Assuming Mr McDowall is 80kg this would be between 80 to 120 mls/h. Alternatively follow burns protocol, which often calculate fluid volumes as 2ml/kg/percentage burn. A flow rate of 80mls/h should be administered via 18 G (green) cannula, whereas a flow rate of 120mls should be given via a larger bore 16 G (grey) cannuale. Select a colloid with a low mean molecular weight, e.g. a gelatin such as Gelofusine® to resolve hypovolaemia without overloading left or right ventricle for Mr McDowall. Administer at a rate of 250 mls over 15 minutes via the larger lumen of quad CVC, monitor effect on HR and BP. Administer in small aliquots to produce a known increment in circulating volume. As hypovoalemia and dehydration resolve, observe improvement in haemodynamics, acid base / base deficit. The limitations of administering colloid fluid bolus at speed include risk of left ventricular failure; Mr McDowall has a left ventricular infarcted area. Check the sodium content of selected colloid to reduce risk of hypernatremia; Gelofusine® has 154-mmol/L sodium. A3 Practitioner guided answer based on their local practices (‘wet’ or ‘dry’). Examples of dynamic indicators include right ventricular end diastolic volume, stroke volume variation, cardiac index, HR, BP, FTc, CVP and urine.(See Chapter 20 Haemodynamic Monitoring, p195 for further information on preload and volume indicators.)
Jane Roe Clinical Scenarios © February 2006

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