INTENSIVE CARE UNIT (ICU) BASICS What is the best way to report urine output in the ICU? 24 hrs/last shift/last 3 hourly rate = “urine output has been 2 L over the last 24 hours, 350 last shift, and 45, 35, 40 cc over the last 3 hours†INTENSIVE CARE UNIT (ICU) BASICS What are the 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 INTENSIVE CARE UNIT (ICU) BASICS What is the most common bacteria in ICU pneumonia? Gram-negative rods INTENSIVE CARE UNIT (ICU) BASICS What is the acronym for the basic ICU care checklist (Dr. Vincent)? “FAST HUGâ€: Feeding Analgesia Sedation Thromboembolic prophylaxis Head-of-bed elevation (pneumonia prevention) Ulcer prevention Glucose control ICU FORMULAS AND TERMS What is CO? Cardiac Output: HR (heart rate) × SV (stroke volume) What is the normal CO? 4 to 8 L/min ICU FORMULAS AND TERMS What factors increase CO? Increased contractility, heart rate, and preload; decreased afterload ICU FORMULAS AND TERMS What is CI? Cardiac Index: CO/BSA (body surface area) What is the normal CI? 2.5 to 3.5 L/min/M2 ICU FORMULAS AND TERMS What is SV? Stroke Volume: the amount of blood pumped out of the ventricle each beat; simply, end-diastolic volume minus the end-systolic volume or CO/HR What is the normal SV? 60 to 100 cc ICU FORMULAS AND TERMS What is CVP? Central Venous Pressure: indirect measurement of intravascular volume status ICU FORMULAS AND TERMS What is the normal CVP? 4 to 11 ICU FORMULAS AND TERMS What is PCWP? Pulmonary Capillary Wedge Pressure: indirectly measures left atrial pressure, which is an estimate of intravascular volume (LV filling pressure) ICU FORMULAS AND TERMS What is the normal PCWP? 5 to 15 ICU FORMULAS AND TERMS What is anion gap? Na+ − (Cl− + HCO−3) ICU FORMULAS AND TERMS What are the normal values for anion gap? 10 to 14 ICU FORMULAS AND TERMS Why do you get an increased anion gap? Unmeasured acids are unmeasured anions in the equation that are part of the “counterbalance†to the sodium cation ICU FORMULAS AND TERMS What are the causes of increased anion gap acidosis in surgical patients? Think “SALUDâ€: Starvation Alcohol (ethanol/methanol) Lactic acidosis Uremia (renal failure) DKA ICU FORMULAS AND TERMS Define MODS Multiple Organ Dysfunction Syndrome ICU FORMULAS AND TERMS What is SVR? Systemic Vascular Resistance: MAP – CVP/CO × 80 (remember, P = F × R, Power FoRward; and calculating resistance: R = P/F) ICU FORMULAS AND TERMS What is SVRI? Systemic Vascular Resistance Index: SVR/BSA What is the normal SVRI? 1500 to 2400 ICU FORMULAS AND TERMS What is MAP? Mean Arterial Pressure: diastolic blood pressure + 1/3 (systolic – diastolic pressure) (Note: Not the mean between diastolic and systolic blood pressure because diastole lasts longer than systole) ICU FORMULAS AND TERMS What is PVR? Pulmonary Vascular Resistance: PA(MEAN) – PCWP/CO × 80 (PA is pulmonary artery pressure and LA is left atrial or PCWP pressure) ICU FORMULAS AND TERMS What is the normal PVR value? 100 ± 50 ICU FORMULAS AND TERMS What is the formula for arterial oxygen content? Hemoglobin × O2 saturation (Sao2) × 1.34 ICU FORMULAS AND TERMS What is the basic formula for oxygen delivery? CO × (oxygen content) ICU FORMULAS AND TERMS What is the full formula for oxygen delivery? CO × (1.34 × Hgb × Sao2) × 10 ICU FORMULAS AND TERMS What factors can increase oxygen delivery? Increased CO by increasing SV, HR, or both; increased O2 content by increasing the hemoglobin content, Sao2, or both ICU FORMULAS AND TERMS What is mixed venous oxygen saturation? Svo2; simply, the O2 saturation of the blood in the right ventricle or pulmonary artery; an indirect measure of peripheral oxygen supply and demand ICU FORMULAS AND TERMS Which lab values help assess adequate oxygen delivery? Svo2 (low with inadequate delivery), lactic acid (elevated with inadequate delivery), pH (acidosis with inadequate delivery), base deficit ICU FORMULAS AND TERMS What is FENa? Fractional Excretion of Sodium (Na+): (UNa+ × Pcr/PNa+ × Ucr) × 100 ICU FORMULAS AND TERMS What is the memory aid for calculating FENa? Think: YOU NEED PEE = U (Urine) N (Na+) P (Plasma); UNa+ × Pcr; for the denominator, switch everything, PNa+ × Ucr (cr = creatinine) ICU FORMULAS AND TERMS What is the prerenal FENa value? <1.0; renal failure from decreased renal blood flow (e.g., cardiogenic, hypovolemia, arterial obstruction, etc.) Lab Values Acute Renal Failure BUN-to-Cr ratio: Prerenal? >20:1 Lab Values Acute Renal Failure BUN-to-Cr ratio: Renal ATN? <20:1 Lab Values Acute Renal Failure FENa: Prerenal? <1 Lab Values Acute Renal Failure FENa: Renal ATN? >1 Lab Values Acute Renal Failure Urine osmolality: Prerenal? >500 Lab Values Acute Renal Failure Urine osmolality: Renal ATN? <350 Lab Values Acute Renal Failure Urine Na+: Prerenal? <20 Lab Values Acute Renal Failure Urine Na+: Renal ATN? >40 Lab Values Acute Renal Failure Urine SG (Specific Gravity): Prerenal? >1.020 Lab Values Acute Renal Failure How long do Lasix® effects last? 6 hours = LASIX = LAsts SIX hours Lab Values Acute Renal Failure What is the formula for flow/pressure/resistance? Remember Power FoRward: Pressure = Flow × Resistance Lab Values Acute Renal Failure What is the “10-for-0.08 rule†of acid–base? For every increase of Paco2 by 10 mm Hg, the pH falls by 0.08 Lab Values Acute Renal Failure What is the “40, 50, 60 for 70, 80, 90 rule†for O2 sats? PaO2 of 40, 50, 60 corresponds roughly to an O2 sat of 70, 80, 90, respectively Lab Values Acute Renal Failure One liter of O2 via nasal cannula raises Fio2 by how much? ≈3% Lab Values Acute Renal Failure What is pure respiratory acidosis? Low pH (acidosis), increased Paco2, normal bicarbonate Lab Values Acute Renal Failure What is pure respiratory alkalosis? High pH (alkalosis), decreased Paco2, normal bicarbonate Lab Values Acute Renal Failure What is pure metabolic acidosis? Low pH, low bicarbonate, normal Paco2 Lab Values Acute Renal Failure What is pure metabolic alkalosis? High pH, high bicarbonate, normal Paco2 Lab Values Acute Renal Failure List how the body compensates for each of the following: Respiratory acidosis Increased bicarbonate Lab Values Acute Renal Failure List how the body compensates for each of the following: Respiratory alkalosis Decreased bicarbonate Lab Values Acute Renal Failure List how the body compensates for each of the following: Metabolic acidosis Decreased Paco2 Lab Values Acute Renal Failure List how the body compensates for each of the following: Metabolic alkalosis Increased Paco2 Lab Values Acute Renal Failure What does MOF stand for? Multiple Organ Failure Lab Values Acute Renal Failure What does SIRS stand for? Systemic Inflammatory Response Syndrome SICU DRUGS â– Â Dopamine What is the site of action and effect at the following levels: Low dose (1 to 3 μg/kg/min)? + + dopa agonist; renal vasodilation (a.k.a. “renal dose dopamineâ€) â– Â Dopamine What is the site of action and effect at the following levels: Intermediate dose (4 to 10 μg/kg/min)? + α1, + + β1; positive inotropy and some vasoconstriction â– Â Dopamine What is the site of action and effect at the following levels: High dose (>10 μg/kg/min)? + + + α1 agonist; marked afterload increase from arteriolar vasoconstriction â– Â Dopamine Has “renal dose†dopamine been shown to decrease renal failure? NO â– Â Dobutamine What is the site of action? +++β1 agonist,++β2 â– Â Dobutamine What is the effect? ↑ inotropy; ↑ chronotropy, decrease in systemic vascular resistance â– Â Isoproterenol What is the site of action? + + + β1 and β2 agonist â– Â Isoproterenol What is the effect? ↑ inotropy; ↑ chronotropy; (+ vasodilation of skeletal and mesenteric vascular beds) â– Â Epinephrine (EPI) What is the site of action? ++α1,α2,++++β1,andβ2 agonist â– Â Epinephrine (EPI) What is the effect? ↑ inotropy; ↑ chronotropy â– Â Epinephrine (EPI) What is the effect at high doses? Vasoconstriction â– Â Norepinephrine (NE) What is the site of action? +++α1,α2,+++β1,andβ1 agonist â– Â Norepinephrine (NE) What is the effect? ↑ inotropy; ↑ chronotropy; ++ increase in blood pressure â– Â Norepinephrine (NE) What is the effect at high doses? Severe vasoconstriction â– Â Vasopressin What is the action? Vasoconstriction (increases MAP, SVR) â– Â Vasopressin What are the indications? Hypotension, especially refractory to other vasopressors (low-dose infusion— 0.01–0.04 units per minute) or as a bolus during ACLS (40 u) â– Â Sodium Nitroprusside (SNP) What is the site of action? + + + venodilation; + + + arteriolar dilation â– Â Sodium Nitroprusside (SNP) What is the effect? Decreased preload and afterload (allowing blood pressure titration) â– Â Sodium Nitroprusside (SNP) What is the major toxicity of SNP? Cyanide toxicity INTENSIVE CARE PHYSIOLOGY Define the following terms: Preload Load on the heart muscle that stretches it to enddiastolic volume (end- diastolic pressure) = intravascular volume INTENSIVE CARE PHYSIOLOGY Define the following terms: Afterload Load or resistance the heart must pump against = vascular tone = SVR INTENSIVE CARE PHYSIOLOGY Define the following terms: Contractility Force of heart muscle contraction INTENSIVE CARE PHYSIOLOGY Define the following terms: Compliance Distensibility of heart by the preload INTENSIVE CARE PHYSIOLOGY What is the Frank-Starling curve? Cardiac output increases with increasing preload up to a point INTENSIVE CARE PHYSIOLOGY What factors influence mixed venous oxygen saturation? Oxygen delivery (hemoglobin concentration, arterial oxygen saturation, cardiac output) and oxygen extraction by the peripheral tissues INTENSIVE CARE PHYSIOLOGY What lab test for tissue ischemia is based on the shift from aerobic to anaerobic metabolism? Serum lactic acid levels INTENSIVE CARE PHYSIOLOGY Define the following terms: Dead space That part of the inspired air that does not participate in gas exchange (e.g., the gas in the large airways/ET tube not in contact with capillaries) Think: space = air INTENSIVE CARE PHYSIOLOGY Define the following terms: Shunt fraction That fraction of pulmonary venous blood that does not participate in gas exchange Think: shunt = blood INTENSIVE CARE PHYSIOLOGY Define the following terms: What causes increased dead space? Overventilation (emphysema, excessive PEEP) or underperfusion (pulmonary embolus, low cardiac output, pulmonary artery vasoconstriction) INTENSIVE CARE PHYSIOLOGY Define the following terms: At high shunt fractions, what is the effect of increasing Fio2 on arterial Po2? At high shunt fractions (>50%), changes in Fio2 have almost no effect on arterial Po2 because the blood that does “see†the O2 is already at maximal O2 absorption; thus, increasing the Fio2 has no effect (Fio2 can be minimized to prevent oxygen toxicity) INTENSIVE CARE PHYSIOLOGY Define the following terms: Define ARDS Acute Respiratory Distress Syndrome: lung inflammation causing respiratory failure INTENSIVE CARE PHYSIOLOGY Define the following terms: What is the ARDS diagnostic triad? A “CXRâ€: C: Capillary wedge pressure <18 X: X-ray of chest with bilateral infiltrates R: Ratio of Pao2 to Fio2 <300 (a.k.a. “P/F ratioâ€) INTENSIVE CARE PHYSIOLOGY Define ARDS: Mild? P/F ratio 200 to 300 INTENSIVE CARE PHYSIOLOGY Define ARDS: Moderate? P/F ratio 100 to 200 INTENSIVE CARE PHYSIOLOGY Define ARDS: Severe? P/F ratio ≤100 INTENSIVE CARE PHYSIOLOGY What does the classic chest x-ray look like with ARDS? Bilateral fluffy infiltrates INTENSIVE CARE PHYSIOLOGY How can you remember the Pao2-to-Fio2, or PF, ratio? Think: “PUFF†ratio: PF ratio = Pao2:Fio2 ratio INTENSIVE CARE PHYSIOLOGY At what concentration does O2 toxicity occur? Fio2 of >60% × 48 hours; thus, try to keep Fio2 <60% at all times INTENSIVE CARE PHYSIOLOGY What are the ONLY ventilatory parameters that have been shown to decrease mortality in ARDS patients? Low tidal volumes (≤6 cc/kg) and low plateau pressures <30 INTENSIVE CARE PHYSIOLOGY What are the main causes of carbon dioxide retention? Hypoventilation, increased dead space ventilation, and increased carbon dioxide production (as in hypermetabolic states) INTENSIVE CARE PHYSIOLOGY Why are carbohydrates minimized in the diet/TPN of patients having difficulty with hypercapnia? Respiratory Quotient (RQ) is the ratio of CO2 production to O2 consumption and is highest for carbohydrates (1.0) and lowest for fats (0.7) HEMODYNAMIC MONITORING Why are indwelling arterial lines used for blood pressure monitoring in critically ill patients? Because of the need for frequent measurements, the inaccuracy of frequently repeated cuff measurements, the inaccuracy of cuff measurements in hypotension, and the need for frequent arterial blood sampling/labs HEMODYNAMIC MONITORING What is a Swan–Ganz (PA) catheter? Pulmonary capillary pressure after balloon occlusion of the pulmonary artery, which is equal to left atrial pressure because there are no valves in the pulmonary system Left atrial pressure is essentially equal to left ventricular end-diastolic pressure (LVEDP): left heart preload, and, thus, intravascular volume status. HEMODYNAMIC MONITORING What is the primary use of the PCWP? As an indirect measure of preload = intravascular volume MECHANICAL VENTILATION Define ventilation Air through the lungs; monitored by Pco2 MECHANICAL VENTILATION Define oxygenation Oxygen delivery to the alveoli; monitored by O2 sats and PO2 MECHANICAL VENTILATION What can increase ventilation to decrease PCO2? Increased respiratory rate (RR), increased tidal volume (minute ventilation) MECHANICAL VENTILATION What is minute ventilation? Volume of gas ventilated through the lungs (RR × tidal volume) MECHANICAL VENTILATION Define tidal volume Volume delivered with each breath; should be 6 to 8 cc/kg on the ventilator MECHANICAL VENTILATION Are ventilation and oxygenation related? Basically no; you can have an O2 sat of 100% and a Pco2 of 150; O2 sats do not tell you anything about the Pco2 (key point!) MECHANICAL VENTILATION What can increase PO2 (oxygenation) in the ventilated patient? Increased FiO2 Increased PEEP MECHANICAL VENTILATION What can decrease PCO2 in the ventilated patient? Increased RR Increased tidal volume (i.e., increase minute ventilation) MECHANICAL VENTILATION Define the following modes: IMV Intermittent Mandatory Ventilation: mode with intermittent mandatory ventilations at a predetermined rate; patients can also breathe on their own above the mandatory rate without help from the ventilator MECHANICAL VENTILATION Define the following modes: SIMV Synchronous IMV: mode of IMV that delivers the mandatory breath synchronously with patient’s initiated effort; if no breath is initiated, the ventilator delivers the predetermined mandatory breath MECHANICAL VENTILATION Define the following modes: A-C Assist-Control ventilation: mode in which the ventilator delivers a breath when the patient initiates a breath, or the ventilator “assists†the patient to breathe; if the patient does not initiate a breath, the ventilator takes “control†and delivers a breath at a predetermined rate MECHANICAL VENTILATION Define the following modes: CPAP Continuous Positive Airway Pressure: positive pressure delivered continuously (during expiration and inspiration) by ventilator, but no volume breaths (patient breathes on own) MECHANICAL VENTILATION Define the following modes: Pressure support Pressure is delivered only with an initiated breath; pressure support decreases the work of breathing by overcoming the resistance in the ventilator circuit MECHANICAL VENTILATION Define the following modes: APRV Airway Pressure Release Ventilation: high airway pressure intermittently released to a low airway pressure (shorter period of time) MECHANICAL VENTILATION Define the following modes: HFV High Frequency Ventilation: rapid rates of ventilation with small tidal volumes MECHANICAL VENTILATION Define PEEP Positive End Expiration Pressure: positive pressure maintained at the end of a breath; keeps alveoli open MECHANICAL VENTILATION What is “physiologic PEEPâ€? PEEP of 5 cm H2O; thought to approximate normal pressure in normal nonintubated people caused by the closed glottis MECHANICAL VENTILATION What are the typical initial ventilator settings: Mode? Synchronous Intermittent mandatory ventilation MECHANICAL VENTILATION Tidal volume? 6 to 8 mL/kg MECHANICAL VENTILATION Ventilator rate? 10 breaths/min MECHANICAL VENTILATION Fio2? 100% and wean down MECHANICAL VENTILATION PEEP? 5 cm H2O From these parameters, change according to bloodgas analysis MECHANICAL VENTILATION What is a normal I:E (inspiratory-to-expiratory time)? 1:2 MECHANICAL VENTILATION When would you use an inverse I:E ratio (e.g., 2:1, 3:1, etc.)? To allow for longer inspiration in patients with poor compliance, to allow for “alveolar recruitment†MECHANICAL VENTILATION When would you use a prolonged I:E ratio (e.g., 1:4)? COPD, to allow time for complete exhalation (prevents “breath stackingâ€) MECHANICAL VENTILATION What clinical situations cause increased airway resistance? Airway or endotracheal tube obstruction, bronchospasm, ARDS, mucous plug, CHF (pulmonary edema) MECHANICAL VENTILATION What are the presumed advantages of PEEP? Prevention of alveolar collapse and atelectasis, improved gas exchange, increased pulmonary compliance, decreased shunt fraction MECHANICAL VENTILATION What parameters must be evaluated in deciding if a patient is ready to be extubated? Patient alert and able to protect airway, gas exchange (Pao2 >70, Paco2 <50), tidal volume (>5 cc/kg), minute ventilation (<10 L/min), negative inspiratory pressure (< −20 cm H2O, or more negative), Fio2 ≤40%, PEEP 5, PH >7.25, RR <35, Tobin index <105 MECHANICAL VENTILATION What is the Rapid-Shallow Breathing (a.k.a. “Tobinâ€) index? Rate: Tidal volume ratio; Tobin index <105 is associated with successful extubation (Think: Respiratory Therapist = RT = Rate: Tidal volume) MECHANICAL VENTILATION What is a possible source of fever in a patient with an NG or nasal endotracheal tube? Sinusitis (diagnosed by sinus films/CT scan) MECHANICAL VENTILATION What is the 35–45 rule of blood gas values? Normal values: pH = 7.35 - 7.45 Pco2 =35-45 MECHANICAL VENTILATION Which medications can be delivered via an endotracheal tube? Think “NAVELâ€: Narcan Atropine Vasopressin Epinephrine Lidocaine MECHANICAL VENTILATION What conditions should you think of with ↑ peak airway pressure and ↓ urine output? 1. Tension pneumothorax 2. Abdominal compartment syndrome RAPID FIRE REVIEW What is the diagnosis? 48-year-old male with pancreatitis now with acute onset of respiratory failure, PaO2 to FiO2 ratio of 89, nl heart echo, bilateral pulmonary edema on CXR Severe ARDS What is the diagnosis? 67-year-old female with severe diverticulitis now with acute onset of respiratory failure, PaO2-toFiO2 ratio of 234, nl heart echo, bilateral pulmonary edema on CXR Mild ARDS What is the diagnosis? 22-year-old male s/p MCC 48-year-old now with bleeding through liver and pelvic packs; TEG reveals a progressive narrowing of the TEG tracing over time (small tail) Hyperfibrinolysis What is the diagnosis? 22-year-old female s/p fall with severe TBI, urine output 30 to 50 cc/hr, CVP 15, sodium of 128 SIADH What is the diagnosis? 45-year-old with severe pancreatitis, now with increasing peak airway pressures, decreased urine output, and hypotension Abdominal compartment syndrome What is the diagnosis? 70-year-old male with severe sepsis on three pressors (vasopressors), antibiotics, refractory to fluid bolus and progressively increasing doses of pressors Adrenal insufficiency What is the diagnosis? 44-year-old male with pulmonary contusions s/p several infusions of KCl for hypokalemia but with no increase in post-infusion potassium level Hypomagnesemia What is the diagnosis? 44-year-old female with severe pancreatitis on ventilator ABG reveals pH of 7.2, PO2 of 100, PCO2 of 65, bicarbonate 26 Respiratory acidosis (uncompensated) What is the diagnosis? 65-year-old male s/p pulmonary contusion on a ventilator, ABG reveals pH 7.35, PO2 80, PCO2 of 60, bicarbonate of 35 Compensated respiratory acidosis What is the diagnosis? 34-year-old female s/p liver injury from an MVC on the ventilator, ABG reveals pH 7.23, PO2 105, PCO2 40, bicarbonate 17 Metabolic acidosis What is the diagnosis? 76-year-old male with severe diverticulitis on ventilator, pH 7.35, PO2 76, PCO2 25, bicarbonate 16 Metabolic acidosis with respiratory compensation What is the diagnosis? 45-year-old "found down" with pH of 7.17, PCO2 39, PO2 90, sodium 140, chloride 108, bicarbonate 26 Normal anion gap metabolic acidosis (140–108–26 = 6) What is the diagnosis? 56-year-old female "found down" with pH of 7.19, sodium 140, bicarbonate 18, chloride 100 Increased anion gap acidosis (140–18–100 = 22) What is the treatment? 34-year-old female s/p MVC with carotid dissection on CTA Antiplatelet (aspirin and/or Plavix®) or anticoagulation (enoxaparin or IV heparin or PO anticoagulation medication, classically Coumadin®) therapy What is the treatment? 25-year-old male s/p crush injury with CK of 45,000, dark urine Myoglobinuria: IV fluid hydration, ± bicarbonate IV What is the treatment? DVT prophylaxis for 34-year-old trauma patient with acute renal failure Unfractionated heparin What is the treatment? 78-year-old male in ICU develops SVT and hypotensive 75/palp Synchronized cardioversion What is the treatment? 80-year-old male s/p Hartmann’s procedure for severe fecal diverticulitis, now with urine output of 10 ccs per hour, FENA <1%, creatinine 1.7, BUN-to-rc ratio of >20, urine sodium of 8 Prerenal acute renal failure, treat with IV volumeÂ
