MICU survival guide

September 13th, 2009admin

 

 

I. Handy dosing cards

1.  HTN-emergency meds, anti-arrhythmics, delerium meds (pdf. 230k)

2. Pressors, analgesics, sedatives, and paralytics (pdf. 626k)

*** Remember, before initiating pressors, give IVF boluses.  "You have to fill-up the tank, before stepping on the gas."

You basic pressors are:
Neosynephrine  (phenylephrine): pure alpha ------->reflex brady. Drop in CO. Gut and Renal killer because of the clamp effect. Used in refractory hypotension, especially vasogenic.  Use in a.fib, RVR, or shock with elevated troponins.

Dopamine (DA)----> starting dose 5mcg/kg/min BETA effect. As you approach 10 then you get more and more Alpha. Over 10 and you should switch drugs. DA bad because it can cause lots of arrythmias.

Levophed (norepinephrine)-------> the king of vasopressors. Alpha>Beta. Limited Beta-2 means even more clamp down time. The beta tries to kick the CO up, but cardiac depression can occur if lacking adequate preload/Inotropic support. If your patient is not tanked up enough,  watch out for gut and peripheral LIMB ischemia. 1st line pressor for septic shock.

Vasopressin------->standard dose 0.04ucg/min for shock. Great adjunct to any of the above. Antidiuretic and direct vasopressor effects (V1 and V2 receptors). Also commonly used for 2nd line agent in sepsis.  Usually is not titrated, but rather turned on or off.

Take home points: Pressors buy you time. But not infinite time. Find out the cause of your hypotension. Usually a form of shock. REVIEW SHOCK causes before using pressors.

If you really want to read-up on all the pressors,  Hensley's: A practical approach to cardiac anesthesia. New edition out. Great book. (click on table of contents---> cardiovascular drugs---starts on page 33)   It is concise and goes over every pressor you will need or want to use, mechanism of action, when to use, duration etc.

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II. DKA

Get to know these latest DKA guidelines, especially the handy algorithm charts,

Pearls:

1. Remember, the aim of DKA treatment is to correct the acidosis by stopping the degradation of fats into ketoacids.  Insulin stops this production of ketoacids.  THUS, IV insulin drip must continue until the acidosis resolves (pH >7.3 and/or bicarb >22.  You don't stop simply because the glucose has normalized, or "the anion gap has closed."  The gap can be particularly misleading because all the IVF you are dumping into a patient will really raise the serum Chloride levels. Furthermore, have a low threshold for restarting insulin drip if bicarb levels begin to drop on SQ insulin.

2. Always think about the cause of the DKA.  Remember the 3 I's... Infection, Ischemia, Indiscretion.  Rule out pregnancy in women of child-bearing age, too.  Always consider pan-culturing and prophylactic antibiotics.  To quote one opinionated attending..."what is the harm of giving antibiotics, versus the risk of not giving them?"  Still, remember that in DKA, leukocytosis may be present without infection.  If there is a left shift in the CBC differential, suspect infection.

3. Check labs often.  BG q1-2 hours, BMPq 4-6 hours, CMP, Mg, Phos at least daily.

4. Calcium and Phosphorus- - Phosphate levels are usually low due to urinary losses.
Routine replacement of phosphate in the IVF may actually precipitate tetany in patients
with low calcium levels. If the initial calcium and phosphate levels are close to
normal, there is no need to keep replacing them.  In general, only replace phos if <1.0 or having symptoms.

5. IV bicarbonate generally reserved for pH < 7.

6.  Likely have pseudohyponatremia. For every increase of 100 in glucose, sodium falls by 1.6.

7.  Calculate the adjusted anion gap for any patients with low albumin.  For every 1 gram decrease in albumin from normal will decrease the AG by 2.3,

8. Average adult water deficit is 100mL/kg (5-10L).  Total fluid replacement should take 14-36 hours. Give initial 1-2L bolus of 0/9%NS to restore inravascular volume in the first hour.  If the corrected sodium is still low, continue with 0.9%NS giving 1-2 more liters over the next 2-4 hours.  If corrected Na is normal (or elevated) use 0.45%NS giving 1-2L over next 2-4 hours.  Be careful to avoid fluid overload in patients with cardiac disease.

8.  Abdominal pain?  Remember that amylase elevation is nonspecific in DKA, but lipase elevation is still specific for pancreatitis.

9. DKA diagnostic criteria: (1) pH < 7.3 with ketonemia, (2) bicarb <15, (3) glucose > 250, (4) AG > 10

10. To prevent cerebral edema complications, do not lower the blood glucose too rapidly.  The initial dose of the insulin drip is usually 0 .1 Units/kg/hour.  For profound hyperglycemia ( BG > 1000), lower rates (0.05-0.075 Units/kg/hr) might be preferable.The goal is to lower the serum glucose by 50-100 mg/dl/hr (aim for ~75).

11.  If BG drops too rapidly than desired, increase the dextrose content in the IVF rather than decreasing the insulin.  If the glucose is really fluctuating,  consider the 2 bag method to titirate glucose in IVFs.

12. if potassium <5.3, then add to IVF (20-30 meq/L).  if <3.3, then hold insulin gtt and give IV potassium until >3.3.

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III. Ventilators

1. Initial settings (plan on changes after checking the 1st post-intubation ABG after 30min)

  • Mode AC (assist control)
  • tidal volume 8-10 ml/kg of ideal body weight (600 is the usual starting volume)
  • rate 12-16
  • FiO2-- start at 100%, then titrate down as soon as possible
  • PEEP-- 5 is standard
  • stuff usually set by respirator tech:
    Inspiratory flow ---->  50 L/min
    I:E --->  1:2
    Peeak Pressure 50cm H2O
    humidifier temp 35 degrees C
  • look at CXR.  ET tube ideally 5cm above corina
  • Got ARDS?  Then check out the ARDSnet vent protocol. (pdf. 1MB)

  • Sedation is critical to good ventilation (reduced work of breathing, improved coordination with vent, patient comfort).  Ativan and Versed are commonly used, and Fentanyl (narcotic) can be added.  If sedation is not adequate for safe ventilator use, paralysis may be needed.  Atracurium is the main paralytic used.  Succinylcholine is a short acting paralytic often used for rapid sequence intubations.  Rember that prolonged paralytics (more than 24hrs) can lead to myopathy, especially in patients also on steroids or aminoglycosides.
  • Learn the lingo: (also see this handout of simplified definitions .pdf 476k)
    1. Peak Pressure= maximum pressure during inspiration.  Thus is an index of risk of barotrauma and decreased cardiac output.  One of the most common ventilator alarms is high peak pressures.  Very often this is due to a mucous plug in one of the airways, that requires suctioning.  To buy time while this is done, you can turn the PEEP off.  Bronchodilators (albuterol) may help in COPD patients. 
    2. Plateau pressure.  Is recorded by setting a plateua of 1 second.  Observe on the viewscreen that flow is stopped just after inspiration for that time.  Thus the lung is not moving and pressure equilibrates to this plateau pressure.  These measurements require a fully sedated/parayzed patient.
    3. Positive End-Expiratory Pressure (PEEP).  By applying pressure to always keep intrathoracic pressure high, alveoli are recruited and kept open, thus improving gas exchange.  PEEP of 5cmH2) is standard to improve physiologic function (overcomes resistance of tubing).  A PEEP of 10 is usually not a problem.  Use PEEP increases to reduce oxygen needs and improve pulmonary finction.  DANGERS of PEEP include barotrauma, pneumothorax, and decreased venous return.
    4. Compliance. This is the change in volume for a given change in pressure (i.e. TV divided by [plateau - PEEP] ).  Normal is 50 to 70 for a ventilated patient.  Below 20 is very bad (stiff lung, probably ARDS).  Compliance is one indicator of the health of the lung parenchyma.  Remeber that emphysema patients have high compliances to start with.
    5. Resistance. This the change in pressure for a given flow (i.e. [peak - plateau] / flow rate). Standard is to measure with the flow rate of 60L/min (1L/sec).  Normal is under 20.  Resistance is an indicator of the function of the larger airways.  Remember that high PEEP will artificially lower the resistance, and severe ARDS sometimes pulls the airway walls outward, lowering resistance as well.
    6. Auto-PEEP. In patients with obstructive disease (asthma, emphysema, COPD), expiration takes a long time, and inspiration may occur prior to expiration being over (i.e. "breath stacking").  Just like PEEP, this has the risk of barotrauma and decreased venous return.  You can measure auto-PEEP by using the auto-PEEP button, which involves a 1-sec pause prior to inspiration.  This stop in flow pre-inspiration will cause a sudden rise in presure if there is auto-PEEP.  These measurements require a fully sedated/paralyzed patient.
    7. Waveforms. These are the shapes you seen on the vent view-screen. 
      • Square signifies rapid inflow and outflow of air; is used when high flow is needed (e.g. asthmatics) and in recording peak pressures in order to measure respiratory mechanics.
      • Ramp: shows rapid and slow component to inflow.  This is physiologic, and is used in most cases.
      • Sine: archaic, not used currently.

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IV. Sepsis

Handy Surviving Sepsis Campaign pocket guideline. (pdf.100k).

Sepsis pearls

  • Frequently pimped... SIRS criteria
    1. Temp <36 or >38
    2. hr >90
    3. RR>20 or PCO2< 32
    4. WBC <4 or >12, or >10% bands
    --------------------
    SIRS is having at least 2 of these 4 criteria.
  • "sepsis" is SIRS plus suspected source
  • "severe sepsis" = signs of end organ damage
  • "septic shock" = after 2L IVF, the SBP<90 or or >40mmHg drop, or MAP<60
  • treatment
    1. IVF boluses until CVP 8-12, MAP 65, Urine output 0.5mL/kg/h
    2. panculture, always consider flu swab too
    3. Abx choice.  Give within 1st 60min!. 1st dose is always full dose, then subsequent doses can be renally dosed if indicated.  Vanc, Cipro, and Zosyn is a good initial broad spectrum regimen.  If patient from nursing home, then suspect ESBL, and substitute carbapenem instead of Zosyn.  If pneumonia is suspected, consider substituting linezolid for Vanc (has better lung penetration). 
    4. Levophed is 1st line presser (titrate to MAP of 65), next step would be to add vasopressin
    5. transfuse PRBCs if Hb<7, <8 if h/o CAD, or <10 if ACS/elevated troponins.
    6. consider adding steroids if hypotension remains refractory to pressors.  Use hydrocortisone 100mg IV q8.
    7. consider Xigris (activated protein C) in severe, refractory sepsis (APACHE score >25 and multi-organ dysfunction).  Note, is $$$.  Xigris is conta-indicated if bleeding.
    8. initial Vent settings with sepsis AC, TV 6-8mL/kg IBW, rate 20, PEEP 5, FiO2 100%
    9. if BG consistantly >180, then start insulin gtt.  Start at 2-4u/h.  Goal BG approximating 150 (per NICE_SUGAR trial, no need to keep 80-110, as that increaes the risk of dangerous hypoglycemia.).
    10. DVT prophlaxis with heparin/LMWH, plus TEDS/SCDs in high risk pts.
  • 11.  Start on PPI for GI prophylaxis.
    12. Source control...do imaging to identify possible source of sepsis.
    13.  have 2 large bore IV placed or central line.

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V. Ischemic stroke

See Courtney's handout on Ischemic Stroke Management in the MICU (.doc 25k)

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VI. Hypokalemia

Is a common issue.  Anticipate need for scheduled supplements before levels drop.  IF you need to to replace while at at MCLNO, always consider using the potassium replacement protocol sheet (.pdf 1Mb)

 

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VII. Acid-Base

Handy Acid-base cards (2 page pdf 750k)

Dr. Suma Jain's Acid base handout (superb and comprehensive!) (2page pdf 220k)

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VIII. Tube Feeds and supplements

What to choose?  MCLNO enteral nutrition guide (pdf 2MB)

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IX. Detox

MCLNO Detox protocols. (.doc)

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X. Central line placement

Nice step-by-step procedure guide with pictures.

video:
http://www.anwresidency.com/simulation/videos/vid_cvc_subclav.html

Internal jugular CVL instructions with anatomy review:

http://www.anwresidency.com/simulation/guide/ij.html

video:

http://www.anwresidency.com/simulation/videos/vid_cvc_ij.html

Subclavian:

http://www.anwresidency.com/simulation/guide/subclavian.html

 

 

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XI.  ARDS

Odds are, you will have to make this diagnosis at some point in your ICU career...likely late at night when a patient is crashing.  Learn the 4 criteria well.

1. Acute onset
2. bilateral patchy air-space disease (does not need to be diffuse)
3. PCWP <18 or no clinical evidece of increased LA pressure.  (aka the heart is ok)
4.  PaO2/FiO2 ≤ 200 is ARDS, while PaO2/FiO2 ≤ 300 is ALI