fluids Flashcards
Fluid Composition for Orally Administered Fluid Therapy
FOR EVERY 21 L OF WATER
- NaCl 10 g
- NaHCO3 15g
- KCl 75 g
- K2HPO4 60g
Advantages of hetastarch include maintenance of plasma oncotic effect for up to…
Disadvantages
up to 24 hours following administration and the ability to give as a rapid bolus
negative effect on coagulation has been demonstrated in healthy equids
in critically ill humans: increased risk of mortality and acute kidney injury in patients receiving hetastarch
MAP can also be calculated by
MAP = 1 ⁄3 × (SAP − DAP) + DAP
ideal cuff … ratio for BP measurement
width-to-circumference of 0.25 to 0.35
for use on the tail or limbs of horses
Normal pleural fluid values
protein concentration <25 g/L and
total nucleated cell count <5000/μL.
Pleural air is then evacuated via
placement of a cannula or 14-gauge catheter in the caudodorsal lung field.
The 12th or 13th intercostal space is a suitable location
Excess EDTA in a low-volume sample of peritoneal fuid will
falsely increase the total protein on refractometry (often by 9–10 g/L higher)
influence of abdominal surgery on abdo tap TP/TNCC
Typically, if no enterotomy was performed,
TNCC: increases for 4 to 7 days and normal by 14 days.
TP remain elevated for 3 to 4 weeks after surgery.
how much urine do helthy horses produce?
1 to 2 mL/kg per hour of urine.
What is Obstructive shock
from lack of blood flow through the heart or great vessels as a result of
- thrombosis (atrial or pulmonary),
- constrictive pericarditis,
- cardiac tamponade, or
- pleural space disease (e.g., pneumothorax).32
This condition is characterized by decreased preload OR increased afterload and results in circulatory failure.3
Maldistributive shock
vasodilatory shock
endothelial dysfunction in response to neutrophil generated cytokines, proteases, lipid mediators, and oxygenderived free radicals
septic, anaphylactic, or neurogenic causes
α1-Adrenergic receptor/ Alpha2-adrenergic stimulation have which effect on vascuature?
alpha1 - vasoconstriction
alpha2 - vasodilation
Which effects do Beta 1 and 2 adrenergic stimulation have on the cardiovascular system?
β1-Adrenergic receptor stimulation
- primarily cardiac effects with
- increases in heart rate (chronotropic effect) and
- contractility (inotropic effect).
β2-Receptor stimulation
- vasodilation of the
- arteries of coronary vessels,
- visceral organs, and
- skeletal muscle
Effect of Dopaminergic stimulation on cardiovasc system
active at adrenergic (α and β) and dopaminergic receptors in a dose-dependent manner
- improves myocardial contractility,
- increases heart rate, and
- results in peripheral vasoconstriction.
low doses: rather Beta (pos inotropy)
high doses: rather Alpha (vasopressor ++)
True or false?
Phenylephrine administration results in increased cardiac output.
False
α-agonist resulting in increased Systemic Vascular Resistance, MAP, and
decreased CO.
Vasopressin works on which receptors?
promotion of water conservation in the collecting tubule of nephrons (V2 receptor)
vasoconstriction via V1 receptors
Which signs indicate the limits to fluid resuscitation
60–80 mL/kg total volume,
CVP >15 mm Hg,
declining Pao2,
peripheral edema
Difference between Type A and B lactic acidosis
A: inadequate delivery of oxygen to peripheral tissues resulting from hypovolemia, hypoxemia, anemia, or decreased perfusion pressure
B: abnormal tissue utilization of oxygen, including mitochondrial dysfunction, or abnormal clearance of lactate
How is lactate eliminated from the circulation?
2% unchanged in urine
metabolisation in liver and kidney to glucose or
pyruvate –>> AcCoA
treatment of hypoventilation secondary to head trauma, encephalitis, or hypoxic-ischemic encephalopathy
- Caffeine: most frequently used in practice because of ease of administration, cost, and wide therapeutic index.
- Doxapram has a short duration of action requiring frequent or CRI administration, which limits use despite evidence of improved ventilation. increase in myocardial oxygen consumption!!!
- Theophylline is similar to caffeine; however, it has a narrow therapeutic index with adverse effects
Is rectal fluid administration useful? When and how?
rectal administration at a rate of 5 mL/kg/h TAP WATER
equivalent to more than twice the accepted maintenance fluid rate, was well tolerated by the horses and was technically easy to perform.
a significant decrease in albumin concentration was seen only with i.v. treatment,
not with NGT or rectal fluid treatment.
Why is albumin a high contributor to oncotic pressure in the blood vessels?
Albumin,
- due to its small size (69 kDa),
- negative charge and
- high concentration,
exerts 60–80% of the oncotic pressure (Magdesian 2003).
Size of particles in HES
Older products, such as hetastarch, have higher molecular weights, ranging from 450 kDa to 600 kDa,
whereas newer formulations have much lower molecular weights (e.g. tetrastarch, 130 kDa) only disadvantage: Tetrastarch is cleared quicker
True or False?
The effect of a colloid on oncotic pressure is determined by the number of oncotically active particles in a solution, not the size of the particles.
True
How is HES cleared from the blood?
- Hydroxyethyl starch molecules are excreted primarily (approximately 70%) by the kidneys with a smaller portion being taken up from the plasma by the reticuloendothelial system.
- Small molecules (45–60 kDa) are excreted rapidly into the urine, whereas larger molecules must first be broken down by amylase into a size that can be filtered through the glomeruli (<60 kDa in humans)
effects of HES solutions on the equine kidney
controversy in equids
.No changes were identified in urine GGT:creatinine ratios after infusion of TES in healthy neonatal foals for 24 h after infusion and in healthy adult horses for 4 h after infusion of PES, respectively
- increased glomerular oncotic pressure > decreased urine output (Honore et al. 2008).
- accumulation of starch molecules within the nephrons, leading to swelling of the proximal tubular epithelial cells, termed osmotic nephrosis
effects of HES on coagulation
- Decreases in fibrinogen have been repeatedly documented after HES administration in horses
- incorporation into clots>> weaker clots
- binding of vWF and Factor VIII by HES molecules
which values of routine haematology and biochemistry measurands in the horse might vary more individually, which less?
High individuality
- Haematology (red blood cell count, mean corpuscular haemoglobin and mean cell volume) and
- biochemistry measurands (total protein, globulins, albumin, gamma-glutamyl transferase, aspartate aminotransferase)
low individuality
- Two haematology (mean corpuscular haemoglobin concentration and platelets) and
- three biochemistry measurands (chloride, glucose and sodium)
are there meds that can reduce lactate in the blood?
beta-adrenergic antagonists effectively reduce [LAC].
Increased lactate concentrations [LAC]
effects of xylacine on cerebral perfusion and intracran pressure
6 horses, 15 minutes, 1 mg/kg
Administration of xylazine to anesthetized horses resulted in an
- increased Cerebral Persuion Press due to
- decreased intracranial pressure with
- with concurrent increased MAP.
- >>>>suggesting vasoconstriction
Administration of xylazine to standing horses did not result in a change in ICP but it is likely to increase it with time
How do Plasma-Lyte 148 and Normosol-R differ from LRS
Indications?
more physiologic sodium:chloride ratio and contain magnesium rather than calcium
INDICATED: may be administered concurrently with blood products and bicarbonate
CONTRAINDICATED: in cases where neuromuscular blockade is a concern (e.g., botulism).
Outcome and complications in horses administered sterile or non-sterile fluids intravenously
no difference in s_urvival to discharg_e
Horses that received no sterile fluids were
- more likely to develop a jugular vein complication
- more likely to have electrolyte abnormalities consistent with hyperchloremic metabolic acidosis
prolonged treatment with balanced electrolyte solutions can result in which electrolyte derangements?
how can these be avoided?
Hypernatremia
hypo kalemia, magnesemia, calcemia
start with adding 0,05meq Potassium/HOUR (max 0.5)
add 1g MgSo4 per L
add 10ml Calcium 23% per L
Bicarb - how much and how to administer
Bicarbonate defcit=
(Bicarbonate desired −Bicarbonate measured) × body weight (kilograms) × 0,3 (extracellular fuid compartment coeff)
First, administer 50% of the bicarbonate deficit (see later) rapidly over 1 to 2 hours followed by the remaining 50% over 12 to 24 hours.
DONT MIX WITH CALCIUM
1 g NaHCO3 = ………….mEq
1 g NaHCO3 = 12 mEq NaHCO3
dose and side effects of hypertonic saline administration
2 to 4 mL/kg, administered as rapidly as possible
Iatrogenic metabolic acidosis, hypernatremia, and hypokalemia
For horses with a pH ≤7.2 caused by metabolic derangements (nonrespiratory) following shock - which fluids are indicated?
crystalloid dosing (80 mL/kg in 1 h),
isotonic bicarbonate (1.3%) therapy is indicated.
First, administer 50% of the bicarbonate deficit (see later) rapidly over 1 to 2 hours followed by the remaining 50% over 12 to 24 hours.
vascular space (VS) and extracellular ECF space contain which amount of volume
ECF is roughly 30% of body weight,
VS is roughly 8% of body weight
administration of hypertonic fluid has which side effects
Iatrogenic metabolic acidosis,
hypernatremia, and hypokalemia
may occur after hypertonic saline administration
metaanalyses in humans failed to support the theory of improved resuscitation through the use of colloids over crystalloids;
however, colloids may be indicated in patients with
hypoproteinemia,
severe blood loss, or
those in need of clotting factors or immunoglobulins. (naturak)
!!! side effects of synthetics!!!!!
half life of hetastarch
24h
True or False?
Synthetic colloids do not register on a refractometer.
TRUE
evaluation of oncotic pressure requires the use of a colloid osmometer
Side effects of Hetastarch. Is there an alternative?
increased risk of mortality (human med)
coagulopathies (Equine)
acute kidney injury (human)
use of hetastarch in horses with underlying renal insufficiency is cautioned, and its use is restricted to those with clinical signs of acute hypoproteinemia.
Recently tetrastarch (6%) was evaluated and shown to have a more sustained effect on COP with fewer adverse coagulopathic effects than hetastarch.
Both hetastarch and tetrastarch can be dosed at 10 mL/kg.
Blood transfusions: If cross-matching is unavailable, use a……as donor.
non-Thoroughbred gelding
Abdominocentesis: Excess EDTA in a low-volume sample will falsely
increase the total protein on refractometry (often by 0.9–1.0 g/dL higher)
With intestinal strangulation how does abdominal fluid change in the first 6 hours?
first 1–2 hours: TP increases such that the fluid is clear but more yellow.
After 3 to 4 hours: red blood cells also leak, and the fluid is more orange or pink.
After 6 hours or more, white blood cells increase gradually, with the progression of intestinal necrosis.
Which percentage of neutros is in abdo fluid?
neutrophils make up approximately 40% to 50% of cells, with the remainder being lymphocytes, macrophages and peritoneal cells.
When does abdo fluid normalize post colic sx without enterotomy?
white blood cell count increases for 4 to 7 days and returns to normal by 14 days
total protein elevated for 1 month
Normal horses produce how much urine per hour?
1 to 2 mL/kg per hour of urine.
Obstructive shock results from
lack of blood flow through the heart or great vessels as a result of
thrombosis (atrial or pulmonary),
constrictive pericarditis,
cardiac tamponade, or
pleural space disease (e.g., pneumothorax).
Obstructive shock is characterized by which changes in pre- and afterload?
decreased preload
or
increased afterload
and results in circulatory failure
Administration of IV emergency boluses is stopped when normalization or plateau of perfusion parameters is observed or when limits to fluid resuscitation are reached.
Name three reasons to stop bolusing
60–80 mL/kg total volume,
CVP >15 mm Hg,
declining Pao2,
peripheral edema
Reihenfolge des einsatzes von vasoactive medication in equine patients
- dobutamine (2–5 μg/kg/min)
- Norepinephrine
- Vasopressin
types of lactic acidosis
TYPE A :
inadequate delivery of oxygen to peripheral tissues resulting from hypovolemia, hypoxemia, anemia, or decreased perfusion pressure
TYPE B:
abnormal tissue utilization of oxygen, including mitochondrial dysfunction, or
abnormal clearance of lactate
Hypercapnia (elevated Paco2) is commonly observed in cases of
hypoventilation and V/Q mismatch
V/Q mismatch
Oxygen supplementation is indicated when the Pao2 falls below
Pao2 falls below 60 mm Hg or Sao2 < 90%
Indications for mechanical ventilation include….
Name diseases where this might become necessary
marked hypoxemia or hypoventilation
(pHa <7.3 with Paco2 >65 mmHg or Pao2 <60 mmHg) despite maximal medical therapy, and
fatigue or excessive work of breathing:
botulism,
hypoxemic-ischemic encephalopathy, or
ARDS
Delayed blood gas analysis may result in
increased PaCo2,
decreased pH,
decreased glucose, and
increased lactate
as blood cells continue to metabolize nutrients
PAo2 and its relation to fraction of inspired oxygen (Fio2) in the horse
Pao2 = 5x Fio2 in the healthy standing horse;
therefore, in a patient breathing room air at sea level (Fio2 = 21%), expected Pao2 concentration is approximately 100 mm Hg with an Sao2 >93%
The causes of hypoxemia can be further differentiated through the administration of supplemental oxygen and evaluation of oxygen saturation.
failure to increase Pao2 to 100 mm Hg suggests…
Improvement of Pao2 above 100 mm Hg suggests
failure to increase Pao2 to 100 mm Hg:
right-to-left shunting or
massive pulmonary thromboembolism
Improvement suggests:
V/Q mismatch or a diffusion disturbance
Nutritional Maintenance requirements for healthy adult horses at rest are estimated to be
30 to 40 kcal/kg per day
