Month: February 2020

The History of Mechanical Ventilation

Karen Swecker, RN, MedFlight Infection Control Liaison

Ventilators have become a common piece of equipment in healthcare, saving lives and providing respiratory assistance for those who may be depending on it to stay alive.  Like most equipment in healthcare someone saw a need and started work on coming up with a solution.

The ventilator has a history that begins in the 16th century by Andreas Vesalius, who at the age of 23 taught anatomy.  Due to his dissection of human cadavers, his ideas were greatly frowned upon by the church.  In 1543, Vesalius published a series of books on the human anatomy, describing a tracheotomy and blowing air into the hole to cause the lungs to “rise again”.  Prior to Vesalius, common belief was that the act of breathing caused the heart to beat.

In 1667, scientist Robert Hook demonstrated that blowing air into the lungs kept one alive.  However, it still wasn’t clear why people breathed or why they became pulseless.  The most common belief was that people became unconscious due to a lack of stimulation.  Treatment for this included rolling the person over barrels, putting them over a trotting horse, hanging them upside down, or using a fumigator that blew smoke up the rectum.

During the 1730s, a Scottish surgeon, Wm. Tossach successfully resuscitated a coal miner with mouth to mouth breathing, describing the process in medical literature.  The process included pinching the nose and blowing as hard as he could into the patient’s mouth.  Once the patient regained a pulse the doctor “pushed, pulled, and rubbed” the patient to stimulate circulation.  Mouth to mouth resuscitation became popular until oxygen was discovered in the 1770s.  The belief was that any exhaled air was depleted of oxygen therefore mouth to mouth was of no use to a person in respiratory distress.

Ventilators based on negative pressure were developed in the late 1800s.

The patient sat in a box with the head exposed, a plunger device was used to decrease pressure inside the box causing inhalation, then reversing the process to cause exhalation.  Per the inventor, Alfred Jones, the box” cured paralysis, neuralgia, seminal weakness, asthma, bronchitis, dyspepsia” and many other diseases. 

In 1876, the first iron lung was developed and place along the Seine River to save drowning victims.  The first iron lung to treat polio victims was used in Boston in 1929.  One difficulty with the iron lung was figuring out how to access the patient’s body for care.  To solve this a respirator room was created where the patient’s body lay inside the room with the head sticking out.  Pistons were used to create pressure changes causing air to move in and out of the lungs.  Multi patient ventilation rooms were developed for use during polio epidemics.

During the 1950s, epidemics of polio were occurring, at one point there were 50 patients a day being admitted to a Copenhagen hospital with respiratory muscle paralysis that had a mortality rate of more than 80%.  Tracheostomies and positive pressure respiration use dropped the death rate to 40%.  As there were no individual respirators patients were continuously hand bagged.  These patients were cohorted into the same room… thus creating the first ICU.
Transporting a ventilated patient took a moving truck and a group of strong individuals.

During the 1940s and 1950s, positive pressure invasive ventilation was developed which provided volume controlled ventilation.  There were no alarms or monitors and no specific settings.  Total volume was measure separately.  Soon, a double circuit ventilator was used in both OR and ICU, it included monitoring for pressure and tidal volume, and machine triggered inspiration.   In the 1960s, PEEP became standard care.  By the early 1970s, second generation ventilators monitored tidal volume, respiratory rate and allowed patient triggered inspiration.  Improvements continued at a fast past, developing into the ventilators now in use.  Speculation of the future of ventilators include the ability of the ventilator to integrate with other bedside technology, smart alarms, and decision support.

The ventilator has come a long way in a short time.




Measles 2019 Update

Karen Swecker, RN, MedFlight Infection Control Liaison

Per the CDC, there were 1276 confirmed cases of measles in 31 states.  The outbreak has finally slowed down but cases may still occur.

  • Majority of cases were in unvaccinated people
  • 124 people were hospitalized
  • 61 reported complications including pneumonia and encephalitis
  • Ohio reported 1 case of measles in an adult that was unvaccinated and traveled to a state with confirmed measles cases
  • If you are unvaccinated you have a 90% risk of being infected just being in the room with a measles patient
  • Measles can live up to 2 hours in the air where an infected person coughed or sneezed
  • You can contract the measles via airborne or contact with contaminated surfaces
  • People are infectious 4 days before to 4 days after the rash appears
  • 1 out of 20 children with the measles will get pneumonia (most common cause of measles related death)
  • 1 out of 1000 children with measles will develop encephalitis
  • 1 to 3 out of 1000 children infected with measles will die from respiratory or neurologic complications

The Threat Continues

In December the CDC received reports of measles infected persons traveling through at least 5 separate airports – Chicago O’Hare, Austin-Bergstrom Airport in Texas, Richmond International in Virginia, and the airport in Denver and LAX.

The known measles infected travelers included a person who traveled in Europe in late November and 3 infectious children visiting from New Zealand.  Typical time between exposure and symptoms is between 7 to 14 days.

As a reminder, the symptoms include: high fever, cough, runny nose, red, watery eyes, the rash typically begins 3 to 5 days after the first symptoms.

Skin of a patient after three days of a measles infection.



Norovirus Update

Karen Swecker, RN, MedFlight Infection Control Liaison

Norovirus is a highly contagious infection that can be transmitted via an infected person, contaminated food or water and contaminated surfaces.  Approximately 20 million people are infected with norovirus each year resulting in 70,000 hospitalizations and 800 deaths.  Norovirus is the leading cause of foodborne illness in the US.

A person infected with Norovirus can shed billions of viral particles; however, it only takes around 18 viral particles to cause an infection.   An infected person can spread the disease beginning a few days before symptoms appeal, and continue to be infectious as the virus remains in the stool for 2 weeks or longer.

The symptoms of norovirus appear suddenly and include watery diarrhea, acute onset of nausea and vomiting, abdominal pain and may be accompanied with a fever, headache and body aches.  Symptoms typically appear within 12 to 48 hours after exposure and last 1 to 3 days.

There isn’t a vaccine for Norovirus, prevention relies on:

  • Thorough hand washing with soap and water – recommended over alcohol hand gel
  • Wash fruits and vegetables before preparing and eating
  • Cook shellfish thoroughly – Norovirus can survive temperatures up to 140o F
  • Keep the sick away from food preparation areas
  • If you are sick do not prepare food for others
  • If you are sick do not provide patient care
  • Clean surfaces with a bleach solution (1/3 cup bleach per gallon of water or 1TBSP +1/2 tsp per 32 ounces of water in a spray bottle) immediately after vomiting or having diarrhea. Surfaces should remain wet for 10 minutes to fully kill any pathogens.
    • IMPORTANT: wipe down surfaces with clean water after bleach disinfection
  • Close the toilet lid before flushing – flushing can aerosolize viral particles
  • Handle dirty laundry carefully wearing gloves – disinfect hands and reusable gloves after use

More information may be found at: