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28 Cards in this Set
- Front
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Recognizethe major indications/clinical cases for fluid therapy. |
- Dehydration - Shock – mostcommonly hypovolemic - Providemaintenance requirements - Treatelectrolyte imbalances - Maintainoncotic pressure (colloids) - Diuresis |
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Design a fluid plan (including volume/rate/route & type) based on aclinical evaluation of fluid deficit.
Example: 10%dehydration in 10 kg dog |
Fluid deficit = 10 kg x 0.10 = 1 kg = 1000 ml Maintenance = 10 kg x 50 ml/kg/day = 500 ml/day Total requirement = 1000 + 500 = 1500 ml over 24hours Hartmann's Solution suitable - IV |
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Identify conditions/diseases which may give rise to shock.
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1. Circulatory shock - global energy deficit at cellular level (high morbidity and mortality rates) 2. Hypovolemic shock - results from loss of IVF due to dehydration, blood loss (very common with trauma), 3rd spacing of fluids; most common type 3. Cardiogenic shock - HF 4. Distributive shock - cardiac function and BV not affected, but there's failure of vascular tree to allow appropriate delivery |
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Describe treatment of shock. |
1. FLUID THERAPY (hypotensive resuscitation) 2. Identification and control of any hemorrhage 3. Broad spec bacteriocidal antibiotics 4. GI protectants 5. Vasopressors/inotropes 6. Bicarbonate 7. Glucocorticoids... no benefits documented. |
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Explainhow monitoring of clinical signs, physiological and laboratory data assist inthe diagnosis and treatment of shock. |
1. Physical findings essential (MM color, CRT, pulse rate and quality, HR, RR) 2. Urine output (rate <1ml/kg/hr should be investigated) - indicates hypovolemia & inadequate renal perfusion or renal failure 3. Arterial BP - may be normal in early shock due to compensation & won't fall until severe 4. Blood lactate - produced by anaerobic metabolism in hypoxic cells |
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Recognize fluid products other than crystalloid solutions and have abasic knowledge of their indications. |
Crystalloids - Hartmann's, normal saline, 5% dextrose Other than crystalloids - act in expanding and maintaining intravascular space & require smaller volumes - Indicated with hypovolemia, hypoalbuminemia & larger patients 1. Colloids - Haemacel, Pentastarch/tetrastarch 6% 2. Albumin 3. Hypertonic saline (7.2% NaCl) 4. Blood products |
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Appreciatecomplications which may occur as a result of fluid therapy. |
1. Iatrogenic electrolyte disturbances 2. Catheter related issues 3. Complications with individual products 4. Volume overload -> Chemosis, serous nasal discharge, inc RR, effort and noise, restlessness, peripheral edema and polyuria - Pulmonary & interstitial edema |
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Which of the following descriptions provides the best definition of dehydration? a. A deficit in interstitial fluid b. A deficit in intravascular volume c. A deficit in intracellular fluid d. A deficit in extracellular fluid e. A deficit in total body water |
A deficit in total body water |
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Hypovolaemia is another type of fluid deficit. Which of the following descriptions provides the best definition of hypovolaemia? a. A deficit in extracellular fluid b. A deficit in intravascular volume c. A deficit in interstitial fluid d. A deficit in total body water e. A deficit in intracellular fluid |
A deficit in intravascular volume |
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Clinical signs can be used to determine which type of fluid deficit is present.It is important to determine if the patient is hypovolaemic as this will necessitate more aggressive fluid therapy.From the list below select those clinical signs that are indicative of hypovolaemia in dogs. a. Cool extremities b. Tachycardia c. Sinking of the eye into the orbitd. Dry mucous membranes e. Bradycardiaf. Skin tenting g. Weak peripheral pulses |
a. Cool extremities b. Tachycardia g. Weak peripheral pulses - Hypovolaemia leads to a reduction in blood pressure and tissue perfusion. Weak pulses and cool extremities reflect these changes and heart rate increases in an attempt to compensate (NB: bradycardia may be a feature of hypovolaemia and shock in cats but not dogs).Changes in skin elasticity, eye position and moistness of mucous membranes reflect changes in tissue hydration rather than perfusion and are indicative of dehydration. |
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On clinical examination Tilly appears quiet. Her heart rate is 104 beats per minute and her pulse quality is good. When the skin over her dorsal neck is pinched there is a delay before it sinks back into place and her oral mucous membranes seem a little dry and sticky.Using the Dehydration % Table what do you estimate the fluid deficit to be in Tilly? |
~7-9% Tilly has no signs of hypovolaemia: heart rate is normal and pulses are good. This rules out the larger deficits of 12 and 15%. However Tilly does have some clinical signs: skin tenting and sticky mucous membranes, thus the deficit is 5% or greater. This leaves a choice between 5 and 8% dehydrated. The former is the smallest deficit detectable and so clinical signs will be mild. At 8% dehdration signs consistent with a moderate reduction in tissue hydration are to be expected and this best describes Tilly's signs. |
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Tilly weighs 25 kg. Using the above estimation of 8 % dehydration calculate the fluid deficit in Tilly in litres.Please express your answer as a number only, i.e. no units, to facilitate automatic marking. |
Fluid deficit (L) = body weight x (% dehydration ÷ 100) Fluid deficit = 25 x (8 ÷ 100) = 2 L |
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Which type of fluid would you choose to replace the fluid deficit in Tilly? a. 5% Dextrose b. Gelatin-based colloidal solution e.g. Gelofusine c. 7.2% Sodium chloride d. Hartmann's solution (Compound sodium lactate) e. Fresh whole blood f. 0.9% Sodium chloride g. 0.18% Sodium chloride plus 4% glucose |
d. Hartmann's solution (Compound sodium lactate) Tilly's clinical signs indicate the presence of dehydration without significant hypovolaemia and so an isotonic crystalloid would be an appropriate choice. In the absence of hypovolaemia there is no indication to give colloids. Similarly the patient is neither anaemic nor thrombocytopaenic and so blood products are not required. Of the crystalloids listed 7.2% sodium chloride is hypertonic and therefore contraindicated in dehydration. Of the isotonic crystalloids, two (5% dextrose and 0.18% sodium chloride plus 4% glucose) are used as "maintenance" fluids to provide water and electrolytes when there is a failure of oral intake. They are not suitable to replace ECF deficits. This leaves Hartmann's and 0.9% sodium chloride. Of these Hartmann's is probably the best choice having an electrolyte composition that is closest to that of the plasma. It is also an alkalinising fluid, which may be beneficial in patients with concurrent metabolic acidosis due to bicarbonate loss (quite common in patients with diarrhoea). Sodium chloride 0.9% would be an acceptable alternative. |
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Assuming Tilly (25 kg) has an existing 2L fluid deficit but is no longer vomiting or having bouts of diarrhoea, what is the total volume of fluid in litres that you would administer over the next 24 hours? Please give your answer as a number only, i.e. no units, to facilitate automatic marking |
Total fluid requirement = fluid deficit + ongoing lossess + maintenance requirement (50 ml/kg/day) = 2 + 0 + (50 x 25 ÷ 1000) = 3.25 L |
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What rate of fluid infusion in ml/h would you use in Tilly to administer the total fluid requirement (caclulated above) over the next 24 hours? |
Total fluid requirement = 3.25 L = 3250 ml Hourly fluid requirement = 3250 ÷ 24 = 135 ml The correct answer is: 135 ml/hr |
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f you don't have a fluid infusion pump the rate of fluid administration is controlled by setting a "drop rate" on a giving set. Using a giving set that delivers 20 drops/ml what drop rate indrops/min would be equivalent to the ml/h rate that you calculated above? |
Fluid rate calculated previously = 135 ml/h Fluid rate in ml/min = 135 ml/h ÷ 60 min/h = 2.25 ml/min Drop rate in drops/min = 2.25 ml/min x 20 drops/ml = 45 drops/min |
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Intra-operative blood loss can be estimated from the change in a patient's packed cell volume (PCV) True or False |
False: During haemorrhage all blood components are lost (i.e. RBCs, WBCs, plasma volume, platelets etc.) and so PCV does not fall immediately. Only when the "volume" is replaced, by endogenous compensatory mechanisms and/or administration of IV fluids does PCV fall, often several hours after the blood loss occurred. |
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Intra-operative blood loss can be estimated by counting the number of blood-soaked surgical swabs True or False? |
True: A standard surgical swab (4" x 4") will hold 5 - 10 ml of blood |
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Intra-operative blood loss can be quantified by weighing blood-soaked swabs True or False |
True: One ml of blood weighs slightly more than 1 g (~ 1.3 g). |
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For some types of surgery lost blood can be collected in a suction apparatus and quantified in this way True or False? |
Partially true (!): Blood collected by suction is often diluted with saline flush and so to estimate the volume lost the PCV of the fluid must be compared to the PCV of the patient.For example: before surgery a patient has a PCV of 50%. During surgery 100 ml of blood-stained fluid with a PCV of 25% are collected in the suction apparatus.Blood lost = Suction PCV / Patient PCV x 100 ml = 25/50 x 100 = 50 ml |
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Having estimated the volume of blood lost, the next step in deciding what treatment to provide is to express the loss as a percentage of the patient's blood volume.What is the approximate blood volume in the cat? |
60 ml/kg - varies slightly between books It is slightly higher in the horse (60-70 ml/kg) and the dog (80-90 ml/kg). |
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Sweep weighs 4 kg. You estimate that he has lost approximately 80 ml of blood. What percentage of blood volume does this loss represent? |
Blood volume for cat = 60 ml/kg Sweep weighs 4 kg so has a blood volume of: 60 x 4 = 240 ml A blood loss of 80 ml represents 80 ÷ 240 x 100 = 33.3 % (i.e. a third of blood volume) |
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Assuming that Sweep has lost 80ml of blood which treatment would you choose: a. 5% Dextrose b. 0.18% Sodium chloride + 4% glucose c. Oxyglobin d. 0.9% Sodium chloride e. Gelofusine f. Unmatched fresh whole blood transfusion g. 7.2% Sodium chloride h. Hartmann's solution |
Oxyglobin = Sweep has lost a substantial amount of blood, approximately 33% of blood volume and so a fluid with oxygen-carrying capacity should be given. Oxyglobin is a polymerised bovine haemoglobin solution, which does not induce transfusion reactions. It has the advantage of a long shelf-life and so can be very useful in the management of unexpected intra-operative bleeding. Although not licensed in the cat it can be used safely in this species. It is however a strong colloid (i.e. it has a high oncotic pressure) and so there is a risk of volume overload if it is administered too quickly. Fresh whole blood, if available, is generally a good option BUTmust be typed and matched for administration to cats. A high proportion of cats have naturally occurring red cell antibodies and so a potentially lethal transfusion reaction can occur the first time unmatched blood is administered. This does not apply to all species. Dogs lack naturally occurring red cell antibodies and so a reaction to the first blood transfusion is unlikely, even if unmatched. |
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Watson, a 7 year old Weimaraner weighing 30 kg is admitted with a suspected gastric dilation and volvulus. On clinical examination heart rate is 180 beats/min, femoral pulses are palpable but more peripheral pulses are not. Mucous membranes are pale and extremities feel slightly cold. Respiratory rate is 40 breaths/min. Watson is exhibiting clinical signs of shock and stabilisation with IV fluids is required before proceeding to surgery. Which fluid would you choose to give (NB:may be more than 1 answer)? |
A crystalloid such as Hartmann's, a colloid such as Gelofusine or a combination of crystalloid and colloid are all suitable options. - Hypertonic saline (7.2% sodium chloride) is a useful adjunct in some patients but should not be used as the sole IV fluid. - Blood transfusion is not indicated at this stage as the deficit is primarily affecting intravsacular volume (i.e. the patient is not anaemic, thrombocytopaenic etc). - 5% dextrose is contraindicated as it will exert a hypotonic effect encouraging a shift of fluid out of the intravascular volume (NB: 5% dextrose is isotonic "in the bag" but becomes hypotonic in the patient as the dextrose is metabolised to water). |
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There is no evidence that colloids are superior to crystalloids in the treatment of shock. The main practical difference between crystalloid and colloids when treating shock is the volume required. The shock dose of crystalloid in the dog is approx 90 ml/kg whereas the shock dose of colloid is approximately 20 ml/kg. True or false? |
TRUE |
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Frequent re-assessment of clinical signs is vital to ensure that shock is neither over- nor under-treated. Which of the following variables would be most useful when assessing a shock patient's response to fluid therapy? (may select more than 1) a. Skin tenting b. Measurement of blood pressure c. Peripheral pulse quality d. Heart rate e. Measurement of PCV |
b. Measurement of BP c. Peripheral pulse quality d. HR - Prior to treatment Watson was tachycardic and peripheral pulses could not be paplated. If fluid therapy restores intravascular volume, blood pressure (if it can be measured) should improve. Improved blood pressure will be reflected in better pulse quality and a reduction in heart rate (NB: tachycardia occurs in an attempt to compensate for low blood pressure). - Skin elasticity reflects tissue hydration and in acute shock is unlikely to be altered. Packed cell volume is also unlikely to be useful as it is subject to various conflicting influences. It may be increased in patients with GDV as a consequence of haemoconcentration and is likely to fall following fluid therapy but it may also be affected by any pre-existing disease and/or episodes of blood loss. |
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Rosie, an 8 year old TB cross weighing 500kg, is admitted for surgical treatment of colic. Rosie is also exhibiting signs of shock and fluid therapy is required to stabilise her condition before proceeding to surgery. Which fluid would you choose to use? |
7.2% Sodium chloride (hypertonic saline = 2-5 ml/kg) and Hartmann's solution In dogs and cats isotonic crystalloids such as Hartmann's solution are widely used to treat shock. However in equine patients the shock dose of these fluids is large. Colloids may be more useful as the shock dose is less but these fluids are also expensive and financial considerations often preclude their use. An alternative approach is to use hypertonic saline (2-5 ml/kg) to produce an initial increase in intravascular volume and then follow through with isotonic crystalloid such as Hartmann's. |
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A shock dose of crystalloid approximates to the blood volume and so could be taken as ~ 70 ml/kg in the horse. The shock dose of colloid is generally taken to be similar to that recommended in dogs & cats, i.e. 20 ml/kg. The dose for hypertonic saline is 2-5 ml/kg infused over 15 to 30 minutes.For the following fluids, give the shock dose (in L) required in Rosie (NB: Rosie weighs 500 kg). 1) 7.2% Sodium chloride 2) Hartmann's solution 3) Gelofusine |
1) 7.2% NaCl (Hypertonic saline) = 2-5 ml/kg x 500 kg = 1,000-2,500 ml = 1-2.5 L 2) Isotonic crystalloid = 70 ml/kg x 500 kg = 35,000 ml = 35 L 3) Colloid (Gelofusine) = 20 ml/kg x 500 kg = 10,000 ml = 10 L |
