As has been previously noted, the white blood cell count is "the last refuge of the intellectually destitute." However, within a CBC (especially if a differential is obtained), there is information that can sometimes be of value. One measure, which was noted before COVID but has come under increasing attention in the current pandemic, is the Neutrophil-To-Lypmhocyte Ratio (NLR). Because physiologic stress typically causes the Absolute Neutrophil Count (ANC) to increase and the Absolute Lymphocyte Count (ALC) to decrease, the ratio of the two values (NLR = ANC/ALC) should increase when the body is under stress. Similar to the WBC however, it should be noted that ANY source of physiologic stress can cause abnormalities of the NLR, and thus this is not limited strictly to infectious etiologies.
With that caveat in mind, the NLR can sometimes be a clue to the degree of physiologic stress the patient is under. As lymphopenia is a frequent finding in COVID, the NLR has come under particular interest in the setting of COVID and appears to have prognostic value in COVID+ patients.
It should be kept in mind that inflammatory stressors (e.g. sepsis) are likely to disproportionately raise the NLR relative to noninflammatory stressors (e.g. pulmonary embolism), so a septic patient with an NLR of 10 might not be all that ill, whereas a PE patient with an NLR of 10 may be sicker. As with any single lab, and particularly one so nonspecific, there are no hard and fast cutoffs, and the NLR has to be interpreted in the context of other clinical data (it is very much possible to have a high NLR and not be that sick, or to have a low NLR and be sick... this is only one datapoint and does have pitfalls associated with it). As a rough guide however, a Pulmcrit post by Josh Farkas from 2019 suggested the following interpretation of the NLR:
1-3: Normal
6-9: Mild stress (e.g. uncomplicated appendicitis)
9-18: Moderate stress, may be associated with critical illness
>18: Severe stress, commonly associated with critical illness
The post (see references below) provides an excellent overview of NLR, further information on the uses and pitfalls of NLR, and several additional sources on the subject. It's a very worthwhile read.
Bottom Line: The Neutrophil-To-Lymphocyte Ratio (NLR = ANC/ALC) is one indicator of the degree of physiologic stress, and may be used in conjuction with other clues to determine how sick your patient is.
Carbon monoxide is an odorless gas that can cause neurologic and cardiovascular toxicity. It is produce by combustion of organic materials/fuel such as natural gas (furnace, gas stove, water heater, space heater) or gasoline. DVT/PE has been reported among victims of CO poisoning.
A recently published article investigated the risk of DVT/PE after CO poisoning.
Results
22,699 patients with CO poisoning were identified between 2004 and 2015
30 days after CO poisoning
90 days after CO poisoning
No significant increase in risk > 90 days.
Conclusion
Mortality is high in intracranial hemorrhage, and even higher for anti-platelet associated ICH (AP-ICH). The Platelet Transfusion Versus Standard Care After Acute Stroke Due to Spontaneous Cerebral Hemorrhage Associated with Antiplatelet Therapy (PATCH) trial was shocking: it demonstrated platelet transfusion was associated with worse outcomes, excluding those patients who were planned to go to surgery in the next 24 hours. SCCM and the Neurocritical Care Society recommend AGAINST platelet transfusion in non-operative ICH, but encourage a dose of DDAVP.
But who knows who will go to surgery? If you've been giving platelets and DDAVP to non-operative AP-ICH, you're not alone. So in the July Issue of Crit Care Medicine, the authors of the PATCH trial published a retrospective study of 140 patients, excluding those who immediately had surgery. In this group in which a quarter eventually had decompressive craniectomy and a fifth had an external ventricular drain placed, half received platelets and DDAVP instead of DDAVP alone.
The result? Still no benefit to platelet transfusion (despite the inclusion of patients who went on to have surgery). We all WANT to give platelets to AP-ICH, but there is NO evidence of BENEFIT and we may cause HARM. A test of platelet function (like the TEG) should be performed at the very least to select for patients with actual platelet dysfunction, and transfusion should be limited to patients going to surgery.
Analgesics & Sedatives in the Critically Ill Obese Patient
Sickle cell trait (SCT) is common and often overlooked clinically
-7.3% African Americans
-0.7% Hispanics
-0.3% Caucasians
SCT is a leading cause of exertional death in athletes who play football
The exact mechanism is unknown but likely involves a combination of high intensity exercise, dehydration, heat strain and inadequate opportunity for cardiovascular recovery leading to microvascular erythrocyte sickling.
This leads to hypoxia, cell death, hyperkalemia, and death from arrhythmia.
Presentation often involves rhabdomyolysis and exertional collapse.
In August of 2010 the NCAA enacted legislation requiring documentation of SCT status of all Division 1 athletes (2012 for Division 2 and 2014 for Division 3)
They also mandated education, counseling and issued guidelines for proper conditioning
Sudden death in athletes with SCT was first observed in military recruits in 1970.
Death in African American military recruits was 28 times more likely in those with SCT than in those without.
A 2012 study of football athletes found the risk of exertional death to be 37 times higher in athletes with SCT than in those without.
Despite game/competition situations being more intense, deaths occur almost exclusively during practice and conditioning drills.
Following the 2010 legislation, there has been a 89% decrease in death from SCT in NCAA D1 football.
Workout plans need to account for heat/humidity, the athletes level of conditioning and allow for adequate rest, recovery, hydration. SCT screening is only part of the solution.
A 27 year-old man with history of rheumatoid arthritis presents to the emergency department after ingestion of hydroxychloroquine (20 tablets of 200 mg/tablet). He complains of nausea/vomiting. He appears lethargic. What is the anticipated hydroxychloroquine toxicity and management?
VS: Temp: afebrile, BP: 95/55 mmHg, RR: 23 breaths/min, O2 saturation: 99%
ECG:
Bottom Line: Pregnancy is associated with an increased risk for RCVS, CVT, and Bell’s Palsy. Pregnancy also affects the frequency of migraines due to hormonal fluctuations.
Patient
· A North America multicenter study involving 821 asymptomatic patients who had exposure to Covid-19-positive patients. The study was double-blind, placebo-controlled randomized trial.
Intervention
· Within 4 days of exposure, participants were randomized to receive hydroxychloroquine. Dose of hydroxychloroquine was 800 mg once then 600 mg in 6-8 hours then 600 mg daily for 4 more days.
· There were 414 patients in this arm. Median age 41 years [IQR 33-51]
Comparison:
· Placebo treatment. There were 407 patients in this arm. Median age 40years [IQR 32-50]
Outcome:
· Incidence of either laboratory-confirmed Covid-19 or Covid-19 symptoms within 14 days.
Results:
· 49 (11.8%) patients with treatment had Covid-19 findings (positive tests or symptoms)
· 58 (14.3%) patients with placebo had Covid-19 findings (p=0.35).
· The absolute difference was -2.4%. The number need to treat (NNT) to prevent one infection is 42 patients. Number needed to harm is 50 patients.
· Symptoms were fatigue (49.5%), cough (44.9%), sore throat (40.2%) myalgia (37.4%), fever (34.6%), anosmia (23.4%), shortness of breath (18.7%).
Conclusion:
Hydroxychloroquine prophylaxis did not prevent post-exposure Covid-19 infection.
While taking metronidazole it is advised that patients avoid ethanol use for at least 3 days after therapy due to the possibility of a disulfiram-like reaction. The disulfiram-like reaction presents as abdominal cramps, nausea, vomiting, headaches, and/or flushing and can cause extreme discomfort for patients. A recent case report describes a case of a disulfiram-like reaction in a patient receiving metronidazole and an oral prednisone solution that contained 30% alcohol. This case highlights an important point. Not only should we counsel patients about avoiding alcoholic beverages for at least 3 days after metronidazole therapy, but they should also avoid all alcohol-containing products, such as oral solutions and mouthwash.
Clinical Question: Will resuscitation guided by dynamic assessments of fluid responsiveness in patients with septic shock improve patient outcomes?
Methodology:
Design: Randomized, unblinded clinical trial among adults with sepsis-associated hypotension comparing PLR-guided SV responsiveness as a guide for fluid management (intervention) versus “usual care” at 13 hospitals in the United States and the United Kingdom (randomization was in a 2:1 allocation of SV-guided to usual care).
Inclusion criteria:
-patients presenting to the ED with sepsis or septic shock and anticipated ICU admission.
-refractory hypotension (MAP ≤ 65mmHg after receiving ≥ 1L and < 3L of fluid)
Exclusion criteria:
-infusion of > 3L of IV fluid prior to randomization
-hemodynamic instability due to active hemorrhage
-pregnancy or being incarcerated
-indication for immediate surgery
-acute CVA, acute coronary syndrome, acute pulmonary edema, status asthmaticus, major cardiac arrhythmia, drug overdose, injury from burn or trauma, status epilepticus
-inability or contraindication to passive leg raising
Intervention (in ICU):
-PLRs were performed prior to any treatment of hypoperfusion with either fluid bolus or vasopressors for the first 72 hours after ICU admission or until ICU discharge (whichever occurred first)
-If patient was FR (increase in SV ≥10%) a 500 ml crystalloid fluid bolus was given with repeat PLRs after every fluid bolus
-If the patient was non-FR, initiation or up-titration of vasopressors was prompted with repeat PLRs after significant escalation (an increase of 1 mcg/kg/min norepinephrine)
Results:
-83 patients in Intervention arm, 41 in Usual Care arm
-Both arms received a similar volume of resuscitation fluid prior to enrollment (2.4 ± 0.6 L Intervention vs. 2.2 ± 0.7L Usual Care)
-Positive fluid balance at 72 hours or ICU discharge, was significantly less in the Intervention arm (-1.37L favoring Intervention, 0.65 ± 2.85L Median: 0.53L Intervention vs. 2.02 ± 3.44L Median: 1.22L Usual Care, p=0.02).
-Fewer patients required RRT (5.1% vs 17.5%, p=0.04) or MV in Intervention arm compared to Usual Care (17.7% vs 34.1%, p=0.04)
-ICU length of stay was similar in the two arms
-There was no difference in overall 30-day mortality (6.3% difference, Intervention: 15.7% vs. Usual Care: 22.0%, 95% CI -21.2%, 8.6%)
Implications:
Although this is a smaller, unblinded (also funded by maker of SV monitoring device) study, Douglas et al. demonstrate that limiting fluid administration using dynamic assessments of fluid responsiveness to guide resuscitation in patients in septic shock is likely safe. In fact, this may actually decrease the need for renal replacement therapy and mechanical ventilation amongst this patient population. At the very least, this study adds to the body of literature showing the harms of excessive fluid administration and positive fluid balance.
Bottom line:
If possible, use dynamic assessments of fluid responsiveness in patients with septic shock to guide interventions, particularly for further resuscitation beyond initial fluid resuscitation (~2 liters in this study).
Over the past several days, riot control agents have been used against the protest participants (related to Mr. George Floyd’s death). There are 3 widely used riot control “lacrimating” agents:
These agents (irritants) primarily affect the eye, skin, and respiratory tract.
| Organ | Effect | Management |
| Eyes | · Lacrimination · Blepharospasm · Conjunctiva irritation/conjunctivitis · Periorbital edema · Corneal abrasions | · Copious H20/saline irrigation with Morgan Lensor Nasal Cannula jury-rig · Slit lamp exam for corneal abrasions |
| Skin | · Burning sensation · Blister · Contact dermatitis · 2nd degree burns (mace) | · Wash with soap and water · Wound care |
| Airway/respiratory tract | · Respiratory tract irritation · Rhinorrhea · Laryngospasm · Bronchospasm · Chemical pneumonitis | · B2-agonists for bronchospasm · Steroids if worsening underlying reactive airway disease · CXR to evaluate for possible pneumonitis · Supplementary oxygen as needed |
Mangement:
Asking these allows everybody to understand what the goal really is — what are you really fighting for? It’s for a life that contains certain things.
ILE is considered as one of the “last resort” therapy in cases of life-threatening drug-induced cardiogenic shock or cardiac arrest. Although there are numerous case reports and case series that showed “successful” or “positive” outcome with ILE, here is no clear evidence that lipid emulsion therapy is effective.
A group of researcher reviewed the National Poison Data System (NPDS) to investigate the failure of ILE therapy by reviewing the overdose fatalities reported to NPDS between 2010 and 2015.
Result:
Response to therapy (study cohort)
Adverse effect (n=49)
Conclusion
Background:
· Empiric broad spectrum antibiotic therapy is a mainstay of the management of critically ill patients with septic shock.
· Vancomycin is widely used for the coverage of potential MRSA infection
· Continuous infusion of vancomycin has been repeatedly demonstrated to reach target serum concentrations faster, maintain consistent serum vancomycin levels better, with fewer serum concentration sampling required, and less overall vancomycin required to do so, in both adult and pediatric populations.2-5
Current Article:
Flannery AH, Bissell BD, Bastin MT, et al. Continuous Versus Intermittent Infusion of Vancomycin and the Risk of Acute Kidney Injury in Critically Ill Adults: a Systematic Review and Meta-Analysis. Crit Care Med. 2020;48(6):912-8.
· Systematic review and meta-analysis of 11 studies for a total of 2123 patients
· Comparing continuous versus intermittent vancomycin infusion.
· Primary outcome of AKI, secondary outcome of mortality
· Found a reduction in the incidence of AKI in the continuous infusion cohort:
· No association between infusion strategy and mortality
Considerations:
· Initial loading dose used in most of the studies (15 mk/kg) probably underdosed, current recommendation for 25mg/kg initial loading dose7 (which is not even always effective by itself)8 (Reardon)
· Continuous infusion may be difficult with limited IV access
· AKI associated with increased hospital stay, costs, mortality (although didn’t pan out in study) – worth preventing if possible.
Take Home:
· Give a 25-30mk/kg loading dose of vancomycin in critically ill patients with suspicion of MRSA to achieve target serum concentrations sooner.
· Continuous vancomycin is a viable option and could be considered in ED boarders, especially if there is concern for impending renal injury.
Post concussion musculoskeletal injuries
Sport related concussion (SRC) impairs numerous functions of the CNS.
Traditional research has focused on risk of repeat concussion following clearance and return to sport
Several studies have shown a consistent elevated risk of lower extremity injuries from 90 days up to one year following SRC.
These include lateral ankle sprains and ACL injuries. Risk ranges, 1.3-3.4x.
This risk may be greater in those with multiple concussions.
This elevated rate has been seen in populations ranging from high school, college to professional athletes and has also been seen in the general population.
Persistent neurological deficits in cognitive and postural control, stability and gait deviations have been postulated as potential mechanisms.
These may be potential modifiable risk factors before return to play/activity. This may be a role best served by sport physical therapists to assist with sport specific rehabilitation post concussion.
NHTSA recommends that car seats be replaced following a moderate or severe crash. Car seats do not automatically need to be replaced following a minor crash.
A minor crash is one in which ALL of the following apply:
-The vehicle was able to be driven away from the crash site.
-The vehicle door nearest the car seat was not damaged.
-None of the passengers in the vehicle sustained any injuries in the crash.
-If the vehicle has air bags, the air bags did not deploy during the crash
-There is no visible damage to the car seat.
NEVER use a car seat that has been involved in a moderate to severe crash. Always follow manufacturer's instructions.
A 19 year old man presents with a scalp lesions/burns after an exposure to incendiary agent. His wounds were smoking and they flouresce under UV light.
What is the causative agent?
