What is a PONV?
PONV is the abbreviation for postoperative nausea and vomiting and describes nausea and vomiting after general anesthesia. Besides postoperative pain, PONV is one of the most common complaints after surgery. Every third person suffers from it. If a person is prone to nausea, the probability of developing PONV again under further general anesthesia is significantly increased.
The causes
The exact causes leading to nausea and vomiting after general anesthesia have not yet been clearly determined. Messenger substances such as dopamine, serotonin, acetylcholine and histamine stimulate receptors of the vomiting center in the central nervous system. This receptor zone is located at the bottom of the 4th brain ventricle.
At this point the blood–brain barrier is permeable, toxins can get from the blood to the receptors, triggering vomiting and protecting the person from harmful substances. Chemotherapy-induced nausea is caused by the increased release of serotonin. Which messenger substances play the decisive role in PONV has not yet been fully clarified.
Evidence is provided by the fact that smokers are affected by PONV half as often as non-smokers. Here a connection can be established with changes in the dopamine receptors. It is still noticeable that PONV is more frequently found in laparoscopic operations, uterus and gallbladder removal than average, but the exact connections are still controversially discussed. Risk factors that have been established include a longer duration of anaesthesia, anaesthesia with anaesthetic gas, and the administration of opioids for postoperative pain therapy. In addition, PONV is more common in women, non-smokers and people suffering from motion sickness.
Other accompanying symptoms
Due to the agonizing nausea and vomiting despite an empty stomach, the well-being of those affected is greatly reduced. For the quality management of anesthesia, the well-being of the patient before and after the anesthesia is very important. Cold sweat and chills can occur during a PONV.
Frequent vomiting can cause electrolyte disorders, resulting in cardiac arrhythmia, muscle twitching and cramps, as well as concentration problems and fatigue. By checking the blood, a disturbance in the electrolyte balance can be quickly detected and counteracted with infusion solutions. The loss of fluid can cause the blood pressure to drop, so care must be taken to ensure that those affected are given plenty of fluid, preferably through a vein. If a patient vomits after anesthesia, stomach contents can enter the lungs via the trachea, as the protective reflexes are not yet fully intact. Respiratory disorders and pneumonia can develop.
