Mendelson's syndrome, named in 1946 for American obstetrician and cardiologist Curtis Lester Mendelson, is a form of

chemical pneumonitis Chemical pneumonitis is inflammation of the lung caused by aspirating or inhaling irritants. It is sometimes called a "chemical pneumonia", though it is not infectious. There are two general types of chemical pneumonitis: acute and chronic. Irri ...

or aspiration pneumonitis caused by aspiration of stomach contents (principally gastric acid) during

anaesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), a ...

childbirth Childbirth, also known as labour and delivery, is the ending of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million births glob ...

. This complication of anaesthesia led, in part, to the longstanding ''

nil per os Nothing by mouth is a medical instruction meaning to withhold food and fluids. It is also known as nil per os (npo or NPO), a Latin phrase that translates to English as "nothing through the mouth". Variants include nil by mouth (NBM), nihil/non/nu ...

'' (abbr. NPO; a Latin phrase meaning nothing by mouth) recommendation for women in labour.

Presentation

Mendelson's syndrome is characterised by a bronchopulmonary reaction following aspiration of gastric contents during general anaesthesia due to abolition of the laryngeal reflexes. The main clinical features are signs of general hypoxia, two to five hours after anaesthesia. Such features may include cyanosis, dyspnea, fever, pulmonary wheeze, crepitant rales, rhonchi, and

tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ( ...

with a low blood pressure. Decreased arterial oxygen tension is also likely to be evident.

Pulmonary edema Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due t ...

can cause sudden death or death may occur later from pulmonary complications.

Risk factors

Historically it is said that a patient is at risk if they have: * Residual gastric volume of greater than 25ml, with * pH of less than 2.5 However these are indirect measurements and are not factors that directly influence aspiration risk. Patients with a high risk should have a

rapid sequence induction In advanced airway management, rapid sequence induction (RSI) – also referred to as rapid sequence intubation or as rapid sequence induction and intubation (RSII) or as crash induction – is a special process for endotracheal intubation that is ...

. High risk is defined as these factors: # Non-elective surgical procedure # Light anaesthesia/unexpected response to stimulation # Acute or chronic, upper or lower GI pathology #

Obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...

Opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...

medication # Neurological disease, impaired conscious level, or sedation #

Lithotomy position The lithotomy position is a common position for surgical procedures and medical examinations involving the pelvis and lower abdomen, as well as a common position for childbirth in Western nations. The lithotomy position involves the positioning of ...

# Difficult intubation/airway # Gastrointestinal reflux #

Hiatal hernia A hiatal hernia or hiatus hernia is a type of hernia in which abdominal organs (typically the stomach) slip through the diaphragm into the middle compartment of the chest. This may result in gastroesophageal reflux disease (GERD) or laryngop ...

Eponym

It is named for Curtis Mendelson.

References

External links

* {{Respiratory pathology Syndromes affecting the respiratory system Pneumonia Health issues in pregnancy