Sedating The Critically Ill Patient
Severe acute respiratory failure among patients with PCP pneumonia, especially among those newly diagnosed with AIDS, remains a disease of high morbidity and mortality. Among those requiring mechanical ventilator support, the mortality rate has been reported between 50-70%.
According to ELSO guidelines, pharmacologic immunosuppression (specifically neurtrophil <400/mL) is a relative contraindication. Furthermore, a status predicting poor outcome despite ECMO should also be considered a relative contraindication.
That said, there are several case reports now of successful use of ECMO in AIDS patients, particularly those suffering with PCP pneumonia.
In a case report and literature review published in BMJ in Aug 2017, 11 cases of ECMO (including 1 VA) in AIDS patients were described.
Bottom Line: HIV/AIDS is not an absolute contraindication to VV ECMO therapy in ARDS and may be particularly useful in the treatment of severe PCP pneumonia. Initiation of ECMO in this patient population should be considered on an individual case by case basis.
Background:
We are all familiar with the Surviving Sepsis Campaign recommendation (& CMS core measure) for an initial 30ml/kg bolus of IV crystalloid within the first 3 hours for our patients with septic shock. There is minimal data, however, on how much IVF we should be giving our patients with BMIs ≥30.
A recent study in obese patients with septic shock retrospectively stratified the total fluids administered at 3 hours into 3 different weight categories, to categorize patients as having received 30mL per kg of ___ body weight, whether actual (ABW), adjusted (AjdBW), or ideal (IBW**).
AdjBW = (ABW – IBW) *40% + IBW
They found:
Bottom Line:
**IBW calculated using Devine’s formula for men and women:
Mechanical Ventilation in Shock
Should that patient be admitted to the floor?
Several studies have evaluated factors associated with upgrade in admitted patients from the floor to an ICU within 24 or 48 hours. Elevated lactate, tachypnea, and "after-hours" admissions have been repeatedly identified as some of the risk factors for decompensation.
Two recent studies tried again to identify predictors of eventual ICU requirement...
Best predictors of subsequent upgrade:
The most common reasons for upgrade:
Effect on mortality?
Despite a more stable initial presentation, mortality of patients who decompensated on the floor (25%) matched that of patients initially admitted to the ICU.
*One of the studies noted that although respiratory rate was demonstrated to be the most important vital sign, it was missing in 42% of the study population, while PCO2 was only obtained in 39% of patients.
Bottom Line:
Core Temp <32 degrees leads to impaired shivering and confers increased risk for malignant ventricular dysrhythmias. Core Temp <28 degrees substantially increases risk of cardiac arrest.
If in cardiac arrest:
If perfusing rhythm:
Consider addition of more invasive rewarming techniques in those with hemodynamic/cadiac instability or without access to VA ECMO/CPB:
Consider stopping resuscitation efforts if/when:
Improving CPR Performance
Molecular Adsorbent Recirculating System (MARS) is an artificial liver support system colloquially known in the medical field as "dialysis for the liver."
Take-Home:
1. Consider MARS in your patient with severe acute liver failure due to potentially reversible/recoverable etiology
2. Know if and where MARS is offered near you
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Risk of Pneumocystis pneumonia (PCP) increases with degree of immunosuppression. If clinical suspicion exists (CD4 <200 with cough, pulmonary infiltrates, hypoxic respiratory failure), it is reasonable to initiate empiric therapy.
First line treatment is trimethoprim-sulfamethoxazole (TMP-SMX) orally or IV for 21 days. IV pentamidine has equivalent efficacy to IV TMP-SMX but greater toxicity and is generally reserved for patients with severe PCP who cannot tolerate or are unresponsive to TMP-SMX.
Importantly, adjunctive corticosteroids have been shown to significantly improve outcomes (mortality, need for ICU admission, need for mechanical ventilation) in HIV-infected patients with moderate to severe PCP (defined by pO2 <70 mmHg on Room Air).
· Ideally steroids should be started BEFORE (or at the same time as) Pneumocystis-specific treatment to prevent/mitigate the sharp deterioration in lung function that occurs in most patients after initiation of PCP treatment. This is thought to be secondary to the intense inflammatory response to lysis of Pneumocystis organisms, which can cause an ARDS-like picture.
· Recommended dosing schedule: 40mg prednisone twice daily for 5 days, then 40mg once daily for 5 days, followed by 20mg once daily for the remaining 11 days of treatment.
Bottom Line: In patients with moderate to severe PCP (pO2 <70 mmHg on RA), don’t forget to initiate adjunctive corticosteroids early (at the same time you initiate empiric therapy for PCP).
Post-Arrest Tidal Volume Setting
Negative-pressure pulmonary edema (NPPE) is a well-documented entity that occurs after a patient makes strong inspiratory effort against a blocked airway. The negative pressure causes hydrostatic edema that can be life-threatening if not recognized, but if treated quickly and appropriately, usually resolves after 24-48 hours. These patients may have any type of airway obstruction, whether due to edema secondary to infection or allergy, laryngospasm, or traumatic disruption of the airway, such as in attempted hangings.
Management:
1. Alleviate or bypass the airway obstruction.
· Usually via intubation; may require a surgical airway
· If obstruction in an intubated patient is due to biting on tube or dyssynchrony, add bite-block (if not already in place), sedation, and even paralysis if needed.
2. Provide positive pressure ventilation and oxygen supplementation.
3. Use low tidal volume ventilation.
4. In severe hypoxemia without shock, add a diuretic agent and consider additional measures such as proning and even ECMO if the hypoxemia is refractory to standard therapy.
Background: Sedation and analgesia are key components for mechanically ventilated patients. While significant data exists regarding how to manage sedation and analgesia in the ICU setting, very little data exists on management in the ED.
Data: A prospective, single-center, observational study of mechanically-ventilated adult patients used linear regression to identify ED sedation practices and outcomes, with a focus on sedation characteristics using the Richmond Agitation-Sedation Scale (RASS).
Findings:
Bottom line: Avoid early deep sedation in your intubated patients as this may be directly associated with increased mortality. Instead, a goal RASS of 0 to -2 should be appropriate for most non-paralyzed, mechanically-ventilated ED patients, extrapoloating from ICU guidelines.
Hyponatremic Encephalopathy
Catastrophic Antiphospholipid Syndrome (CAPS):
A life-threatening “thrombotic storm” of multi-organ micro & macro thrombosis in patients with antiphospholipid syndrome (known or unknown).
Triggered circulating antibodies (usually by infection, but can be prompted by malignancy, pregnancy, and lupus itself) cause endothelial disruption and inflammation leading to prothrombotic state, commonly with SIRS response.
Mortality is high at an estimated 40%.
Confirm diagnosis with antiphospholipid antibody titers.
Treat ASAP with unfractionated heparin, corticosteroids, and Hematology consultation for plasma exchange and/or IVIG.
--RV systolic function is negatively affected by high RV afterload
--High mean airway pressures on the ventilator (particularly in modes such as APRV [airway pressure release ventilation]) can induce RV dysfunction
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Improving Resuscitation Performance
When surveyed, half of general medicine patients interviewed stated that they would prefer to have a loved one present if they were to develop cardiac arrest and require CPR. So far, studies have demonstrated that…
Allowing family presence during CPR is associated with the following benefits to family members:
And is NOT associated with a difference in:
Ventilation During Cardiopulmonary Resuscitation
In patients with persistent VT/VF cardiac arrest, giving epinephrine before the 2nd defibrillation attempt (which should follow initial shock and 2 minutes of CPR) is associated with decreased ROSC, decreased hospital survival, and decreased functional outcome.
Take Home Point:
"Electricity before Epi" in patients with persistent VT/VF arrest, at least for the initial epinephrine dose.
The poor sensitivity of bedside echocardiography to identify all-comers with pulmonary embolism is well documented. Most series cite a sensitivity and specificity of 31% to 72% and 87% to 98%, respectively (1,2). But as Nazerian et al demonstrate in their recent publication in Internal and Emergency Medicine, the diagnostic performance of bedside echocardiography is far more reliable in the subset of patients presenting in shock (3).
Of the 105 patients included in the final analysis, in 43 (40.9%) PE was determined to be the etiology of their shock. Bedside echo demonstrated notable diagnostic prowess when employed in this subset of patients, sensitivity (91%), specificity (87%), –LR (0.11), +LR (7.03). The sensitivity and –LR were further augmented when the venous US of the LE was included (sensitivity of 95% and –LR of 0.06) in the diagnostic workup.
