“Happy Hypoxia” may Cause Death in COVID-19

“Happy Hypoxia” may Cause Death in COVID-19

by Karishma Abhishek on Jun 14 2021 3:37 PM
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  • Broad spectrum of COVID-19 presentations pose profound mortality and morbidity rates throughout the world
  • One of the principal and defying reason for COVID mortality is “Happy Hypoxia”, that is estimated to occur in 30% of the patients who require hospitalization
  • The patient does not have any significant respiratory difficulties even at low oxygen saturations and severe COVID-19 infection until it results in a critical level of high fatality.
  • It is thereby required to continuously monitor oxygen saturations at home with pulse oximeters in COVID-patients and prompt immediate care to the suspected ones.
COVID-19 pandemic has led to serious mortality and morbidity rates throughout the world with its wide spectrum of presentations varying from a mild asymptomatic infection to acute respiratory distress syndrome.
One of a prime and challenging reason for COVID mortality is “Happy Hypoxia”, that allows the patient to present late to the healthcare. It is estimated that 30% of the patients who require hospitalization have happy hypoxia.


What is “Happy Hypoxia”?

Hypoxia refers to very low oxygen levels in the blood. The normal oxygen saturation in a healthy person is above 95%. But COVID-19 patients may display dangerously a deterioration of even 40%. This results in breathlessness in affected patients.

However in happy hypoxia, also known as silent hypoxemia, is defined by marked arterial hypoxemia with no corresponding symptoms of respiratory distress, making the patients appear on the outside, to be alright and “happy”.


Do Not Ignore the Symptoms

The patient does not have any notable respiratory difficulties even at low oxygen saturations and severe COVID-19 infection until it results in a critical level of high lethality. However unnoticed symptoms like lips or skin discoloration to red or purple, profuse sweating despite any arduous physical work could indicate warning signs of happy hypoxia.

“In some instances, the patient is comfortable and using a phone at a point when the physician is about to insert a breathing [endotracheal] tube and connect the patient to a mechanical ventilator, which, while potentially lifesaving, carries its own set of risks,” says Rd. Martin J. Tobin, a professor of pulmonary and critical care medicine at the Loyola University Medical Center, in Maywood, IL.

Generally, the homeostatic mechanism of the body hints at least some sensory information to communicate to the brainstem for eliciting a compensatory reflex respiratory response. This effect lowers the CO2 level.

However, patients with happy hypoxia have no deliberate awareness of low oxygen/ hypoxia. The unclear mechanism behind this complication puzzles even the clinicians to cope with the management of coronavirus pneumonia.


Mechanism: Why is Happy Hypoxia Dangerous?

The primary cause of happy hypoxia is known to be widespread clotting in the complex network of small blood vessels in the lungs.

It is recognized that COVID-19 induced pneumonia often leads to hypoxemic respiratory failure or type 1 respiratory failure. This is reported to occur due to low levels of oxygen (hypoxia) that in turn induces constriction of blood vessels of lungs (pulmonary vasoconstriction) or secondary antiphospholipid syndrome.

Normally, hypoxia-induced pulmonary vasoconstriction is an adaptive natural response of the body to accomplish homeostasis and cope with diseases like pneumonia. This, in turn, may enable more ventilation (perfusion) near the healthy segments of the lungs/better-ventilated alveoli (functional unit of lungs), causing a ventilation and perfusion mismatch.

These changes gradually induce a marked increase in oxygen gradient followed by lung edema and alveolar collapse which again decreases the oxygenation of the blood and worsens hypoxia in COVID-19.

So in patients at risk of happy hypoxia with no signs of breathlessness (dyspnea) are more vulnerable to COVID-19 complications. A better understanding of these mechanisms might thus enhance patient care in the upcoming days.

Right Way of Happy Hypoxia Management

Despite the fact of whether the person has mild or severe symptoms of COVID-19 or even is asymptomatic, there is a lingering possibility that the individual could be suffering from happy hypoxia.
  • The COVID-positive patients are thereby expected to keep monitoring their oxygen saturations at home with inexpensive devices called pulse oximeters.
  • Clip the pulse oximeter firmly onto the fingertip to painlessly analyze the oxygen levels in the bloodstream flowing through the region.
  • Supplemental oxygen is the first crucial step for COVID-19 therapy, along with appropriate respiratory support to improve survival rate.
  • It is therefore mandatory to recognize happy hypoxia in COVID-19 patients, regardless of the cause, as it can save lives by prompting immediate care of the patients.

Endure Precautions against the Virus

  1. Happy hypoxia in COVID-19: The Paradoxical killer - (
  2. Why COVID-19 Silent Hypoxemia Is Baffling to Physicians - (
  3. Hypoxia and thrombosis in COVID-19: new considerations for air passengers - (
  4. Hypoxic hospitals after happy hypoxia during COVID-19 pandemic - (
  5. Is 'happy hypoxia' in COVID-19 a disorder of autonomic interoception? A hypothesis - (