Monitoring Flashcards
What is the definition of intraabdominal hypertension?
sustained or repeated pathologic elevation of IAP of >12 mm Hg
What is abdominal compartment syndrome?
sustained increase in intraabdominal pressure of >20 mm Hg that is associated w/ new organ dysfunction/failure
approximately how many ICU patients (people) have abdominal hypertension?
32-50%
How many human ICU patients have intraabdominal hypertension severe enough to be classified as having abdominal compartment syndrome?
14% of the patients who have intraabdominal hypertension
What are 4 conditions that are associated with increased risk of intraabdominal hypertension in people?
- diminished abdominal wall compliance
- increased intraluminal content
- increased abdominal content
- capillary leak syndrome
T/F: in human studies it is determined that a physical exam is a reliable tool to evaluate intraabdominal pressure?
false
Briefly describe the method for determining intraabdominal pressure
U. bladder method is gold standard
- Urethral catheter placed- tip just inside trigone
- sterile urine collection system hooked up to 2 three way stop cocks
- water manometer attached to upright stopcock port
- 35 or 60 ml syringe of 0.9% NaCl attached to distal stopcock
- bladder emptied
- 0.5 to 1 ml/kg (max 25 ml/patient) NaCl instilled
- system zeroed to midline, stopcock closed to fluid source, and pressure is read
What is normal intraabdominal pressure in a dog? A cat?
0-5 cm H2O dogs
6-11 cm H2O cats
What are some hemodynamic effects of increased intraabdominal pressure?
Initially increased CVP & RA/pulmonary pressure; then decreased cardiac output; can falsely increase CVP
Name some renal effects of intraabdominal hypertension
decreased GFR and urine output, oliguria/anuria when IAH >25 cm H2O
Name some pulmonary and thoracic effects of IAH
Decreased pulmonary compliance, decreased chest wall compliance, more severe lung injury
What type of ventilator setting is recommended in patients with IAH?
volume controlled
Name CNS effects of IAH
increased intracranial pressure
Name visceral effects of IAH
hDecreased hepatic, portal, intestinal and gastric blood flow; decreased lymphatic drainage, increased intestinal permeability, possible increased bacteremia from gut
Name systemic/hormonal effects of IAH
Increase in ADH, elevated plasma renin activity, increased aldosterone levels, increased epi and norepi, rise in IL1B, IL6, TNFalpha, MODS, thrombotic disease, impairment of wound healing
What is the recommended course of action if your patient has an IAP of 10-20 cm H2O?
ensure normovolemia, pursue underlying cause
What should you do if your patient has an IAP of 20-35 cm H2O?
volume resuscitate if necessary; perform diagnostics to identify cause, consider decompression
Recommendation if patient’s IAP is >35 cm H2O?
decompression via paracentesis or surgical explore is strongly recommended; consider managing patient as open abdomen
What percent of the original fluid volume that enters the nephron will be excreted as urine?
Less than 1%
Between what MAP is auto regulation maintained?
Between 80 and 180 mmHg
This means that renal blood flow and therefore GFR is maintained
What is the lowest normal urine output value reported for dogs?
0.27 ml/kg/hr
What is the difference between absolute and relative oliguria?
Absolute oliguria refers to a UOP less than 1 ml/kg/hr in a hydrated, well-perfused patient.
Relative oliguria refers to a UOP between 1 and 2 ml/kg/hr in a patient receiving IV fluids
Name some common conditions that can cause pre-renal oliguria
Severe dehydration, hypovolemia, hemorrhage, cardiac failure, SIRS, sepsis
A urine sodium of less than what value is consistent with the action of aldosterone? (in the absence of diuretic administration or intrinsic renal disease)
Urine Na of less than 20 mEq/L
A urine sodium level of what value supports a diagnosis of syndrome of inappropriate ADH?
Serum hyponatremia with urine Na of more than 40 mEq/L
Name 10 causes of pre-renal polyuria
Increased intake (polydipsia, fluid administration)
Drugs (diuretics, alpha 2 agonists, K agonists, alcohols, glucocorticoids, anticonvulsants)
Hormonal conditions (cushings, addisons, DI, hyperthyroidism, cerebral salt wasting syndrome)
Electrolyte abnormalities (hypokalemia, hypercalcemia)
Osmotic conditions (DM, salt ingestion or administration, glycols)
E. coli endotoxin
Liver disease
what is special about a swan-ganz catheter in comparison to other pulmonary arterial catheters?
it has a sensor 4 cm distal to the tip that allows temp measurement
what type of PAC can measure blood oxygenation?
oximetry thermodilution catheter
what are most thermodilution catheters (besides swan-ganz) made of? why?
polyurethane, it softens at body temperature
how big should the catheter introducer sheath be for a PAC?
at least 1 size larger than the catheter itself (i.e. a 6-6.5 fr introducer for a 5 fr catheter)
describe the 2 different ports and what they are used to measure in a PAC designed for thermodilution method of cardiac output
proximal port- CVP port; measures RA or CV pressure; used for fluid boluses
distal port-central lumen; measures PA pressure and PCWP; samples mixed venous blood
what is the K constant of the steward-hamilton equiation?
computation constant that is manually entered into computer that adjusts for amt of thermal signal during each measurement, volume of catheter dead space, and specific heat/volume/gravity of the injectate used
briefly describe the technique for CO measurement using a PAC
1.5 ml/kg of saline of known temp injected into proximal port; the thermistor probe on distal end of PAC measures change in blood temp and calculates CO based on AUC of temperature; the bolus should be given as quickly as possible to minimize changes in temperature
what does PCWP estimate?
LV preload (LV end diastolic pressure)
in which patients might PCWP not be accurate as an estimate for LV preload?
pulmonary hypertension, mitral regurgitation, decreased ventricular compliance; patients on PPV
why might RV end diastolic volume be useful as an estimate of volume status?
if patients are on PPV with PEEP or other scenarios in which PCWP may not be accurate for indicating LV end diastolic pressure
what is required of the patient/ECG to measure RVEDV?
catheter must be synced to ECG; R-R interval must be regular
besides PCWP and RA pressure and CO, what other measurements/diagnostics can be made using PAC?
pulmonary angiography, calculate systemic vascular resistance, pulmonary vascular resistance
t/f- a recent meta analysis of PAC monitoring showed no increased morbidity but no benefit?
true
patients with which type of shock may benefit the most from PAC measurement?
cardiogenic; the other types of shock showed uncertain benefit in 1 study
briefly describe placement of a PAC (without flow directed placement)
clip/prep wide area of skin; place sterile drapes and use sterile gown/gloves/mask/cap; sedation of patient with benzo/opioid; local with lidocaine; skin incision over vessel; placement of introducer sheath into external jugular vein via cutdown or seldinger technique; premeasure to cardiac structures; wrap the neck up; make sure the balloon is good; flush all ports with hep NaCl before placing
describe flow-directed placement of a PAC
attach the distal port of catheter to a calibrated pressure transducer and connection to a monitor; monitor pressure tracing as catheter is introduced into jugular vein; once the catheter is in the RA the balloon can be inflated with ~1.5 ml of air; make sure the balloon is always deflated before withdrawing catheter to prevent valvular damage and knotting of catheter
t/f- the balloon of a PAC should always be deflated after PCWP measurement?
true; to avoid unnecessary obstruction of blood flow
what might be seen on the ECG if the PAC is contacting the RV wall?
ventricular arrhythmias