COVID-19 evolving indications for intubation
Hypoxemia and tachypnea should not be the sole indications for intubation, but rather a complete clinical assessment including work of breathing, mental status and increasing PaCO2 and/or acidosis. Based on experience in NYC, patients who present early in the disease course with oxygen saturations in the 80’s, but who are otherwise clinically well and relatively asymptomatic, do not require intubation. There have been suggestions that these patients may benefit from prone positioning and HFNC (see below). The recommendation early in the COVID pandemic to strongly consider early intubation in all patients with oxygen saturations <90% despite non-invasive oxygenation may not be the best approach.
Suggested stepwise approach to respiratory support for COVID-19
With surgical mask for all steps and negative pressure room for HFNC, CPAP, Endotracheal intubation where possible
Based on ED and ICU experience in New York, Level C evidence
Suggested oxygenation strategies algorithm AIME
Prone position ventilation
Proposed mechanisms for prone positioning
- Induces homogeneous compliance across the chest wall – Anterior chest wall – Weight of mediastinum – Improved displacement of abdomen contents
- Better recruitment of posterior/dependent lung zone
- May lead to an alteration of blood flow and better ventilation/perfusion matching
- Improved drainage effect on respiratory secretions
- Reducing ventral-dorsal transpulmonary pressure difference
- Reduced lung compression
- Improved lung perfusion
Consistently, most trials demonstrate improved oxygenation with ventilation in the prone position. One randomized trial and several meta-analyses also suggest a mortality benefit in those with severe ARDS. Trials have consistently shown that in most patients with ARDS (up to 70 percent), prone ventilation increases PaO2 allowing a reduction in the FiO2. Most patients who demonstrate a response do so within the first hour but delayed responses beyond that have been observed. The PROSEVA trial and several meta-analyses have reported mortality benefits from early, high-dose prone ventilation in patients with severe ARDS (defined by them as PaO2:FiO2 <150 mmHg). There is no evidence that prone ventilation prevents organ system dysfunction and reduces the intensive care unit (ICU) length of stay.
Sun, Qin, et al. “Lower mortality of COVID-19 by early recognition and intervention: experience from Jiangsu Province.” Annals of Intensive Care 10.1 (2020): 1-4.
Restrictive fluid strategy for COVID-19 patients with respiratory failure
- Aggressive fluid resuscitation should generally be avoided in COVID-19 patients
- COVID-19 patients seem to be very sensitive to fluid overload similar to HAPE patients.
- Consider norepinephrine at 5-10mcg/kg/min rather than a fluid bolus to maintain MAP>65
- For hypovolemic patients give small crystalloid bolus (250cL) and reassess volume status frequently
- Avoid fluid resuscitation to clear the lactate in euvolemic patients, as the high lactate is more likely a result of the catecholamine surge associated with severe hypoxemia and respiratory distress, than hypovolemia
Sarah Reid’s take home points on COVID pediatric considerations
Andrew Morris updates
3. We still don’t know “real” ICU mortality—because the various experiences are … varied. China: lots of non-vented patients. Italy: catastrophic scenario. England: right-censoring of data means that they excluded patients on a vent for longer than usual. For all: unclear about no. taken off vent for palliative or even rationing.
4. Transmission routes – Looks like pseudo-droplet spread in some manner. Also looks like “infected” can reduce spread by surgical mask—which justifies asymptomatic population wearing masks to protect infecting others. We don’t know if it will reduce acquisition. The difference between public masking to reduce spread vs. reducing acquisition is an important one. Probably what motivates most people is not getting infected, but we don’t have great evidence masking will do that, and it probably de-emphasizes hand hygiene.
CAEP suggested ED discharge criteria (based on Level C evidence)
1. Has access to food, water, communications, safe shelter
2. Is at baseline level of function
3. O2 saturation >94% on RA
4. RR<20, HR<110, BP at baseline or expected for age/sex
5. Does not appear clinically decompensated
6. Walk test: can walk 30 meters with <10% drop in O2 saturation (even if CXR or POCUS +ive)
Consider discharge advice for patient to perform walk test at home (ideally with O2 sat probe) and return to ED if O2sat<95%
Do you need an N95 mask when performing an NP swab for COVID-19?
Use of N95 mask is not warranted for NP/OP swab
- There is no evidence that cough generated with NP/OP swab procedure leads to increased risk of transmission via aerosols.
- HCW conducting this procedure should do so in a separate/isolation room, be well trained in the procedure, wear droplet precaution PPE, and request the patients to cover their mouth with a medical mask or tissue during NP swab.
COVID-19 pathophysiology and clinical features similar to HAPE: Should we consider HAPE treatments for COVID-19 patients?
High Altitude Pulmonary Edema (HAPE) and COVID-19 have many similarities:
- Decreased ratio of arterial oxygen partial pressure to fractional inspired oxygen with concomitant hypoxia and tachypnea
- Tendency for low CO2 levels
- CT findings of ground glass opacities and patchy infiltrates
- Elevated fibrinogen levels which are likely an epiphenomenon of edema formation rather than coagulation activation
- Bilateral diffuse alveolar damage associated with pulmonary edema, pro-inflammatory concentrates
- Lead to ARDS
There has been a suggestion to study the efficacy of proven therapies for HAPE in COVID-19 patients such as acetazolamide, nifedpine and phosphodiesterase inhibitors.
Solaimanzadeh I. Acetazolamide, Nifedipine and Phosphodiesterase Inhibitors: Rationale for Their Utilization as Adjunctive Countermeasures in the Treatment of Coronavirus Disease 2019 (COVID-19). Cureus. 2020;12(3):e7343.
COVID-19 protected code blue
Excellent overview: Protected Code Blue https://rebelem.com/covid-19-protected-code-blue/
ED separation of COVID/Non-COVID is critical
Separate entrance, exit; NO CROSSING between, fully independent of each other.
One way path through enter-assess/treat-out a different way (where possible)
Assign high risk staff (age, co-morbidities) to Non-COVID side. Even if an asymptomatic COVID patient comes there, the viral load will be lower, less change of transmission to others.
Whether you are in the COVID or non-COVID areas all staff and patients get surgical masks, social distancing and isolation where possible still applies.
Triage as COVID and non-COVID.
COVID-19 Lab Prognostication
Quote of the week
There are times when you can beckon,
There are times when you must call.
You can take a lot of reckoning,
But you can’t take it all.
There are times when I can help you out,
And times when you must fall.
There are times when you must live in doubt
And I can’t help at all.
Three blue stars rise on the hill
Sing no more now just be still
All these trials soon be past
Look for something built to last.
Built to last till time itself falls tumbling from the wall
Built to last till sunshine fails and darkness moves on all
Built to last while years roll past like cloudscapes in the sky
Show me something built to last or something built to try
-Jerry Garcia/Robert Hunter