SR 65 - Surgical Intensive Care Flashcards
How is an ICU note written?
By systems: - Neuro (GCS, MAE, pain control) - Pulmonary (vent settings) - CVS (pressors, swan numbers) - GI (gastrointestinal) - Heme (CBC) - FEN (Chem10, nutrition) - Renal (urine output, BUN, Cr) - ID (Tmax, WBC, antibiotics) Assessment/plan
Possible causes of fever in the ICU?
Central line infection Pneumonia/atelectasis UTI, urosepsis Intra-abdominal abscess Sinusitis DVT Thrombophlebitis Drug fever Fungal infection, meningitis, wound infection Endocarditis
What sit he most common bacteria in ICU penumonia?
Gram-negative rods
Basic ICU care checklist?
FAST HUG
- Feeding
- Analgesia
- Sedation
- Trhomboembolic prophylaxis
- Head-of-bed elevation
- Ulcer prevention
- Glucose control
What is CO?
Cardiac output = HR X SV
What is normal CO?
4-8L/min
What factors increase CO?
Increased contractility, HR, preload
Decreased afterload
What is CI?
Cardiac index = CO/BSA
What is normal CI?
2.5-3.5L/min/M2
What is SV?
Stroke volume
Amount of blood pumpoed out of the ventricle each ebat
EDV-ESV or CO/HR
What is normal SV?
60-100cc
What is CVP?
Central venous pressure
Indirect measurement of intravascular voume status
What is normal CVP?
4-11
What is PCWP?
Pulmonary Capillary Wedge Pressure
Indirectly measures left atrial pressure, which is an estimate of intravascular volume (LV filling pressure)
What is the normal PCWP?
5-15
What is the anion gap?
Na - (Cl + HCO3)
What are the normal values for anion gap?
10-14
Why do you get an increased anion gap/
Unmeasured acids are unmeasured anions in teh equation that are part of the ‘counterbalance’ to the sodium cation
What are the causes of incrased anion gap acidosis in surgical patients?
Starvation Alcohol (ethanol, methanol) Lactic acidosis Uremia (renal failure) DKA
What is SVR?
Systemic vascular resistance
MAP - CVP / CO x 80
What is SVRI?
Systemic Vascular Resistance Index
SVR/BSA
What is normal SVRI?
1500-2400
What is MAP?
Mean arterla pressure
DBP + 1/3 SBP
(not the mean b/c diastole lasts longer)
What is PVR?
Pulmonary vascular resistance
PA (mean) - PCWP / CO X 80
What is the normal PVR value?
100 +/- 50
What is the formula for arterial oxygen content?
Hb X SaO2 x 1.34
What is the basic formula for oxygen delivery? Full formula?
CO x (oxygen content)
CO x (1.34 x Hg x SaO2) x 10
What factors can increase oxygen delivery?
Increased CO by increasing SV, HR or both
Increased O2 content by increasing Hb content, SaO2 or both
What is mixed venous oxygen saturation?
SvO2
The O2 saturation of teh blood in teh right ventricle or pulmonary artery
An indirect measure of peripehral oxygen suplly and demand
Which lab values help assess adequate oxygen delivery?
SvO2 - low with inadequate delivery
Lactic acid - elevated
pH - acidosis
Base deficit
What is FENa?
Fractional Excretion of Sodium
(Una x Pcr / Pna x Ucr) x 100
What is the prerenal FENa value?
How long das Lasix effect last?
Six hours
What is the formula for flow/pressure/resistance?
Pressure = Flow x Resistance
Effect of PaCO2 on acid-base status?
For every increase in PaCo2 by 10mmHg, pH falls by 0.08
One liter of O2 via nasal canula raises FiO2 by how much?
3%
SICU Drugs:
Dopamine
Site of action - dependant on doses
- Low dose (1-3ug/kg/min): Dopa agonist, renal vasodilation
- Intermediate dose (4-10): + a1, ++B1; positive ionotropy and some vasocontriction
- High dose (>10): +++a1 agonist; marked afterload increase from arteriolar vasoconstriction
Has ‘renal dose’ Dopamine been shown to decrease renal failure?
No
SICU Drugs:
Dobutamine
SOA: +++B1 agonist, ++B2
Effect: increased inotropy; increased chronotropy; decrase in SVR
SICU Drugs:
Isoproterenol
SOA: +++B1 and B2 agonist
Effect: Increase inotropy, increased chronotropy; vasodilation of skeletal and mesenteric vascular beds
SICU Drugs:
Epinephrine
SOA: ++ a1, a2, ++++B1/2 agonist
Effect: Increased inotropy, increased chronotropy
SICU Drugs:
Norepinephrine
SOA: +++a1, a2, +++B1/2 agonist
Effect: Increased inotropy, increased chronotropy, ++ increas in BP
What is the effect of Epinephrine at high doses?
Vasoconstriction
What is the effect of high dose Norepinephrine?
Severe vasoconstriction
SICU Drugs:
Vasopressin
Effect: Vasoconstriction, increases MAP, SVR
Indications: Hypotension, refractory to other vasoporessors
SICU Drugs:
Nitroglycerine
SOA: +++venodilation, +ateriolar dilation
Effect: Increased venous capacitance, decreased preload, coronary arteriole vasodilation
SICU Drugs:
Sodium nitroprusside
SOA: +++ venodilation, +++ arteriolar dilation
Effect: Decreased preload and afterload, allowing BP titration
What is the major toxicity of Sodium Nitroprusside?
Cyanide toxicity
Define Preload
Load on the heart msucle taht stretches it to EDV = intravascular volume
Define afterload
Load or resistance the heart must pump against = vascular tone = SVR
Define contractility
Fource of heart muscle contraction
Define compliance
Distensibility of heart by the preload
What is the Frank-Starling curve?
Cardiac output increases with increasing preload up to a point
What is the clinical significance of the steep slope of the Starling curve relating EDV to CO?
Demonstrates the importance of preload in determining CO
What factors influence the oxygen content of whole blood?
Hemoglobin concentration and the arterial oxygen saturation
Partial pressure of oxygen dissolved in plasma plays a minor role
What factors influence mixed venous oxygen saturation?
Oxygen delivery (Hb concentration, arterial O2 sat, CO) and oxygen extraction by the peripheral tissues
What lab test for tissue ischemia is absed on teh shift from aerobic to anaerobic metabolism?
Serum lactic acid levels
Define dead space
Part of inspired aire that does not participate in gas exchange
Define Shunt fraction
Fraction of pulmonary venous blood that does not participate in gas exchange
What causes increased dead space?
Overventilation (emphysema, excessive PEEP)
Underperfusion (PE, low CO, pulmonary artery vasoconstriction)
At high shunt fractions,w aht is the effect of increased FiO2 on arterial PO2?
Shunt fraction>50%, changes in FiO2 have NO effect on arterial PO2
You want to minimize FiO2 to prevent oxygen toxicity
Define ARDS
Acute respiratory distress syndrome
Lung inflammation causing respiratory failure
What is the ARDS diagnostic triad?
CXR:
- Capillary wedge pressure
What does the classic CXR look like with ARDS?
Bilateral fluffy infiltrates
At what concentration does O2 toxicity occur?
FiO2 >60% x 48hrs
What is the only ventilatory parameters that have been shown to decreased mortality in ARDS patients?
Low tidal volumes (
What are the main causes of CO2 retention?
Hypoventilation
Increased dead space ventilation
Increased CO2 production (hypermetabolic states)
Why are carbohydrates minimized in patient having difficulty with hypercapnia?
Respiratory Quotione is ration of Co2 production to O2 consumptoin
The RQ is highes for carbohydrates (1.0) and lowest for fats (0.7)
Why are indwelling arterial lines used for BP monitoring in critically ill patients?
Need for frequent measurments
Inaccuracy of repeated cuff measurements
Inacuraccy of cuff measurements in hypotension
Need for frequent ABGs
Which values are obtained from a SGC?
CVP, PA pressures
PCWP, CO, PVR, SVR
Mixed venous O2 sat
What is PCWP?
PCP after ballon occlusion of the PA, which eaquals elft atrial pressure
LAP is equal to LVP/EDP, left heart preload, and intravascular volume status
What is the primary use of PCWP?
Indirect measure of preload = intravascular volume
Has use of SGC been shown to decrease mortality in ICU patients?
No
Define ventilation
Air moving through the lungs
Monitored by PCO2
Define oxygenation
Oxygen delivery to the alveoli
Mesasured by O2Sat and PO2
What can increase ventilation to decrease PCO2?
Increased RR
Increased TV
(Increasing minute ventilation)
What is minute ventilation?
Volume of gas ventilated through the lungs
RR x TV
Define tital volume
Volume delived with each breath
6-8cc/kg on ventilator
Are ventilation and oxygenation related?
No - you can have an O2Sat of 100% and PCO2 of 150
O2Sat do NOT tell you anything abotu PCO2
What can increase PO2 in the ventilated patient?
Increased FiO2
Increased PEEP
Define IMV
Intermittent Mandatory Ventilation
Patient can breath on their own, but if they don’t breath within a specific time, the machine breathes
Can breath above the mandatory rate without help from the ventilator
Define SIMV
Synchronous IMV
Delivers mandatory breath synchronously with patient’s initiated effort. If no breath is initiated, breath will be initiated by machine.
Patient’s breath triggers the machine to supplement the breath
Define A-C
Assist-Control venitlation
Ventilator delievers breath when patient initiates a breath
If the patient does not breath , ventilator takes control
All breaths are by the ventilator
Define CPAP
Continuous Positive Airway Pressure
Delieves continuous pressure during expiration and inspiration, but no volume breaths
Patient breaths on own
Define Pressure Support
Pressure is delieved with initiated breaths
Decreases work of breathing by overcoming the resistance in the venitlatory circuts
Patient breaths on own
Define APRV
Airway Pressure Release Ventilation
HIgh airway pressure intermittently released to a low airway pressure
Define HFV
High frequency ventilation
Rapid rates of venitlation with small tidal volumes
What is the effect of PP ventilation in patients with hypovolemia or low lung compliance?
Decreased VR
Decreased CO
Define PEEP
Positive end expiration pressure
Pressure maintained at the end of a breath - keeps alveoli open
What is ‘physiologic PEEP’?
5cmH2O
Approximates normal pressure in normal non-intubated people caused by the closed glottis
What are the AE of increasing levels of PEEP?
Barotrauma (injury to airway = PTX)
Decreased CO from decreased preload
What are the typical initial vent settings?
IMV TV = 6-8ml/kg VR = 10bpm FiO2 = 100% and wean down PEEP = 5cmH2O
Then change based on ABGs
What is normal I:E?
1:2
When would you use an inverse I:E ratio?
Ex - 2:1, 3:1
To allow for longer inspiration inpatients with poor compliance
To allow for alveolar recruitment
When would you use a prolonged I:E ratio?
Ex. 1:4
COPD
To allow time for complete exhalation
Prevents ‘breath stacking’
What clinical situations cause increased airway resistance?
Airway or endotracheal tube obstruction Bronchospasm ARDS Mucous plug CHF --> pulmonary edema
What are the presumed advantages of PEEP?
Prevention of alveolar collapse and atelectasis
Improved gas exchange
Increased pulmonary compliance
Decrease shunt fraction
What are the possible disadvantages of PEEP?
Decreased CO (esp in Hypovolemia) Decreased gas exchange Decreased compliance with high levels of PEEP Fluid retention Increased ICP Barotrauma
What parameters must be evaluated in deciding if a patient is ready to be extubated?
Alert and able to protect airway Gas exhange (PaO2 >70, PaCO2 5cc/kg) Minute ventilation (
What is the Rapid-Shallow Breathing (AKA Tobin) Index?
RR:TV
What is the possible source of fever in a patient with an NG or nasal endotracheal tube?
Sinusitis
Diagnose by sinus films or CT
What medications can be delievered via an endotracheal tube?
Narcan Atropine Vasopressin Epinephrine Lidocaine 'NAVEL'
What conditions should you think of with increased peak airway pressure and decreased urine output?
Tension pneumonthorax
Abdominal compartment syndrome
