There are so many variables to monitor during CPR; speed and depth of compressions, rhythm analysis, etc. But how much attention do you give to the ventilations administered?

The right ventricle (RV) fills secondary to the negative pressure created during spontaneously breathing. However, during CPR we administer positive pressure ventilation (PPV), which increase intra-thoracic pressure thus reducing venous return to the RV, decreasing cardiac output, and coronary filling. PPV also increases intracranial pressure by reducing venous return from the brain.

So our goal for ventilations during cardiac arrest should be to minimize the intra-thoracic pressure (ITP); we can do this by remembering to ventilate "low (tidal volumes) and slow (respiratory rates)"

• Low: Use only one-hand while bagging, this will give the patient 500-600cc per breath. Using two-hands provides ~900-1,000cc per squeeze (more than we normally ventilate patients who have a pulse).
• Slow: Ventilate patients at 8-10 breaths per minute. The less you ventilate the less time the patient spends with positive ITP. Observational studies have demonstrated that providers ventilate too fast during code so the use of a metronome or timing light provides critical feedback.

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Happy New Year!!!

My new year's resolution is to use less antibiotics (and eat more Cap'n Crunch Berries)

Will I be successful?

A multi-center, ICU, observational study looking at over 900 patients from 67 ICUs showed that half of all empiric antibiotics ordered in patients are continued for at least 72 hours in the abscence of adjudicated infection.

• We have been well trained to start antibiotics but stopping or limiting use can be difficult
• The greater the severity of illness, the longer the antibiotics were continued in this study

Things to consider:

The same way we try and limit central line use, we should try and decrease antibiotic usage on a daily basis

Tips to decrease use: daily clinical pharmacist input, ID specialist involvement, automated stop dates, 72 hour vancomycin cessation protocols, incentives for de-escalation, educational resources

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Acute Chest Syndrome

• Acute chest syndrome (ACS) accounts for the most common cause of ICU admission and the most common cause of death in sickle cell patients.
• Important pearls for ACS include:
  • Chlamydophila pneumonia is the most common bacterial cause of ACS in adults, whereas Mycoplasma pneumonia is the most common bacterial cause in children.
  • CXR abnormalities may be absent early in disease.
  • Children are more likely to have middle lobe disease, in contrast to adults who often have lower lobe involvement.
  • Acute RV failure is a well recognized complication of ACS - use ultrasound to evaluate the RV and be careful with fluids.

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The EuroTherm3235 Trial was a randomized, multi-center trial to study hypothermia (32-35^oC) in severe, traumatic brain injury¹:

• Hypothermia was compared with hyperosmolar therapies (hypertonic saline and mannitol) as "Stage 2" management.
• While hypothermia did successfully reduce ICP, functional outcomes (as measured in Extended Glasgow Outcome Score [GCS-E]) trended towards harm at six months (though not significantly different).
• Take-home: The study design has significant flaws, but the lack of clear benefit of hypothermia is consistent with previous studies² and suggests that fever prevention or controlled normothermia (36^oC) may be ideal for severe TBI patients, but needs further study.

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• What type of fluid we use in critical care resuscitation has been hotly debated for some time
• The most recent battles have been played out between NS and plasmalyte or buffered solutions
• There has been some evidence that high chloride solutions can lead to renal injury requiring renal replacement therapy (RRT)
• Does a buffered crystalloid reduce renal complications compared with normal saline in patients admitted to the ICU?
• The SPLIT Trial (Saline vs Plasma-Lyte) from New Zealand ICU's adds more to our knowledge about this topic while enrolling over 2,000 patients
• Summary:

1. Primary outcome was a rise in creatinine
2. There was no difference in the primary outcome or incidence of AKI
3. There was no difference in use of RRT or mortality
4. Suggesting that is doesnt make too much of a difference

• There were some limitations: 90% of patients were given fluid before enrollment that was buffered crystalloid and patients were only given around 2 liters on average of fluid in the ICU

The Bottom Line: This was a nicely designed study to evaluate the safety of both fluids. It does suggest that either fluid type is for the most part OK. But in patients requiring hefty fluid boluses, we should be cautious in what type of fluid we choose.

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Mechanical Ventilation for Septic Patients in Resource-Limited Settings

• An international team of physicians just published a series of recommendations for ventilatory support of septic patients in resource-limited settings.
• Pearls from these recommendations include:
  • Elevate the head of the bed to 30^o - 45^o
  • Consider tidal volumes of 5 - 7 ml/kg PBW in all patients
  • Use minimum levels of PEEP ( 5 cm H₂O) in all patients with sepsis and acute respiratory failure (unless the patient has moderate to severe ARDS)
  • Lower F_iO₂ to target SpO₂ > 88% or PaO₂ > 60 mm Hg
  • Use lung ultrasound to evaluate pulmonary edema when CXR is not available
  • Consider using SpO₂ to FiO₂ (S/F) as an alternative to P/F when blood gas analyzers are not available

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--The role of antibiotics in acute exacerbations of COPD remains controversial in many settings. However, a recent Cochrane review concludes that antibiotics have "large and consistent" benefit in ICU admissions [1]:

• decreased length of hospital stay
• decreased treatment failure
• decreased mortality

--However, patients on antibiotics had increased side effects, are at risk for increased drug-drug interaction (think azithromycin/levofloxacin), and the effect on multi-drug resistance is unclear.

--GOLD Guidelines are a bit more liberal with their recommendations for antibiotics [2], recommending antibiotics based on symptoms or in patients needing mechanical support.

--TAKEAWAY -- if your patient needs BiPAP or ICU, they should also get antibiotics!

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• Invasive candidal infections can carry a high mortality (up to 40%) and can hard to diagnose
• In the ICU it is important to know which patients are at risk for developing invasive candidal infections

Risk factors for invasive candidal infections

• Critical illness (long ICU stays)
• Abdominal surgery (anastomotic leaks, repeat laporatomies)
• Necrotizing pancreatitis
• Hematologic malignencies
• Solid organ transplant
• Solid organ tumors
• Neonates (low birth wt, preterm)
• Use of broad spectrum antibiotics
• Central lines/PICC lines
• TPN
• Hemodialysis
• Steroid use
• Candidal colinization (urine, sputum)  

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Pain Management in the Critically Ill Patient

• Pain is common, often underappreciated, and routinely undertreated in our critically ill patients.
• Poorly treated pain has been shown to adversely affect both short- and long-term outcomes.
• Key pearls when treating pain in the critically ill:
  • Vital signs should not be used in isolation to assess pain
  • Use a validated assessment tool to objectively quantify pain (i.e., Critical Care Pain Observation Tool)
  • An analgosedation strategy (analgesics before sedative medications) has been shown to decrease duration of mechanical ventilation and decrease ICU LOS
  • Opioids have no maximum or ceiling dose. The appropriate dose is that which controls pain with the fewest side effects.

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There is more than the standard preparations of plasma, platelets, and PRBCs in the blood bank. Certain patients will require these specialized preparations when a transfusion is required. Here are three to know:

• Leukoreduced (PRBCs are run through a filter to reduce the total WBC burden)
  • Most of the blood in USA is leukoreduced
  • Should be requested for pre-transplant patients and patients who previously experienced febrile non-hemolytic reactions
• Irradiated PRBCs (radiation incapacitates donor WBCs)
  • Irradiation prevents the fatal transfusion-associated graft versus host disease, which occurs in patients who are severely immunosuppressed or who are closely related to the blood product donors.
• Washed RBCs/platelets (washing removes plasma, cell fragments and excess potassium)
  • Washed cells are used for neonates/pediatric patients due to sensitivity to potassium in normal products; in adults, it is used for patients with prior allergic reactions to blood products or IgA deficiency

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• A recent trial looked at the three common sites for central venous catheters in 3471 catheter insertions
• The primary outcome was a composite of catheter-related bloodstream infection and DVT
• The femoral line group had a higher risk of DVT and infections although the risk from both is still very low
• Pneumothorax occurred in 1.5% of subclavian lines and 0.5% of jugular lines
• Subclavian lines are thought to have lower infection rates due to a longer subcutaneous courses before entry. They also have the lowest bacterial bioburden and tend to be protected against disruption

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Classically, aortic dissection presents as tearing or ripping chest pain that radiates to the back in a HYPERtensive patient.

However, type A aortic dissections can quickly become HYPOtensive due to any the primary cardiac complications from retrograde dissection into:

• The pericardium causing cardiac tamponade
• The aortic valve causing wide-open aortic insufficiency
• One of the coronary arteries (typically the RCA presenting as inferior STEMI)

Bedside echo can't rule out aortic dissection, but it can help rule in the diagnosis (figure 1) or complications (figure 2) at times.

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• Evaluating the systolic function of the RV is an important skill and there are described methods.
• One of the simplest method is using the tricuspid annular plane of systolic excursion (or T.A.P.S.E.)
• This is how far the tricuspid annulus travels from diastole to systole because the RV contracts in a longitudinal fashion from the base (diastole) to the apex (systole)
• A TAPSE of <17mm is consistent with abnormal function and >17mm is normal. An eyeball method of assessment can be done when grossly obvious or M-mode can be used when an accurate assessment is required.
• The clip below demonstrates the technique, which should always be performed from an apical four-chamber view.
• Want more info on the RV, then click here for a whole podcast on it.

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SIMV (Synchronized intermittent mandatory ventilation)

• A common mode of ventilation that all pratitioners should be familiar with
• It provides a minimum number of fully assisted breaths synchronized with patient respiratory effort
• Patient or time triggered
• Flow limited
• Volume cycled
• Any additional breaths are unassisted and determined by patient effort
• SIMV=AC when heavily sedated
• The idea is exercise the patients lungs but this can lead to increased work of breathing and fatigue, and prolong extubation when used

Hyperoxia in the Critically Ill

• Oxygen is liberally administered to many critically ill patients, thereby exposing them to supranormal arterial oxygen levels.
• Hyperoxia results in the formation of reactive oxygen species, which adversely affect the pulmonary, vascular, cnetral nervous, and immune systems.
• Though the optimal P_aO₂ remains unknown, recent evidence indicates that hyperoxia is associated with increased mortality in post-cardiac arrest, CVA, acute coronary syndrome, and traumatic brain injury patients.
• Take Home Point: Carefully titrate oxygen to the lowest tolerable level to meet the patient's needs.

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Your ESLD patient is hypotensive with a tense abdomen, and he needs a paracentesis!

--ALWAYS use ultrasound to localize a fluid pocket [Fig 1]! Take the time to use color Doppler to look for underlying abdominal wall varices [Fig 2]. Cirrhotic patients frequently have abnormal abdominal wall vasculature [1-2].

--Hemorrhage from paracentesis is exceedingly rare, and reversal of mild coagulopathy probably isn't that important [3-4].

--In hypotensive patients, consider placement of a small pigtail catheter for slow, continuous drainage (e.g. 8.3F pericardiocentesis catheter) instead of large-volume paracentesis. Non-tunneled catheter infection risk goes up after 72h [5].

--Albumin replacement improves mortality and incidence of renal failure in patients with SBP or other infection [6-7].

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The RV is a low-pressure chamber that doesn’t tolerate acute increases in pulmonary pressures (e.g., ARDS, pulmonary embolism, etc.); acute increases can lead to RV dysfunction / failure

Managing RV dysfunction requires a three-pronged approach:

• Optimize preload – give small fluid boluses (e.g., 250cc) but not too much, because too much can worsen RV function. Use ultrasound to determine volume status
• Optimize RV function – Consider starting inotropes (e.g., dobutamine) for better RV contractility and concurrently start pulmonary vasodilators (e.g., inhaled nitric oxide); also minimize hypoxemia and hypercarbia
• Prevent systemic hypotension – hypotension reduces coronary perfusion that leads to RV ischemia and dysfunction; use norepinephrine to keep blood pressure >65
• Bottom-line: Don't under-estimate the importance of the RV when resuscitating your patients 

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Pressure Regulated Volume Control (PRVC)

Here are some basic pearls about PRVC Ventilation

• Form of Assist Control (AC) ventilation: patient initiated or ventilator intiated
• Constant pressure through inspiration
• Decelerating inspiratory flow pattern
• Ventilator adjusts pressure breath to breath based on patient’s airway resistance and compliance
• Not recommended for asthma or COPD
• Set: RR, tidal volume, upper pressure limit, oxygen level, I:E ratio (can start at 1:2), PEEP

Benefits: minimum PIP, guaranteed tidal volume, patient can trigger more breaths, improved oxygenation, breath by breath changes 

Is It Really ARDS?

• Recent literature suggests that the incidence of ARDS in intubated ED patients may be as high as 10%.
• The Berlin Definition of ARDS includes the acute onset of bliateral opacities (CXR or chest CT) that is not fully explained by pulmonary edema or fluid overload.
• Emergency physicians and Intensivists are well versed in lung-protective ventilator settings for patients with ARDS.
• However, several diseases can appear simliar to ARDS and may require different ventilator strategies and treatments.
• In the absence of clinical risk factors for ARDS (e.g., sepsis, trauma), consider the following in your differential:
  • Idiopathic pulmonary fibrosis
  • Interstitial pneumonitis
  • Granulomatosis with polyangitis (Wegener's)
  • Diffuse alveolar hemorrhage
  • Goodpasture's syndrome

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Ever forget all the things that make up MUDPILES in your AG acidosis differential?

Instead, consider the less-complicated mnemonic "KILR"!

K Ketoacidosis (diabetic, alcoholic, starvation)

I Ingestion (salicylate, acetaminophen, methanol, ethylene glycol, CO, CN, iron, INH)

L Lactic acidosis (infection, hemorrhage, hypoperfusion, alcohol, metformin)

R Renal (uremia)

Once you rule out the KLR causes, begin to consider ingestion or a tox source as your source. Remember that many of the listed ingestions can also cause a lactic acidosis.

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