In study session I you have learnt
- Most regional and general anesthetic techniques result in vasodilation, and general anesthetic agents may additionally produce cardiac depression. The anesthetist must select an induction agent that minimizes fluctuations in cardiovascular tone and function.
- In any anesthesia induction, a primary concern is the presentation of pulmonary aspiration, it will occur either by regurgitation or vomiting.
- Fasting cannot guarantee gastric emptying. Patients who have been traumatized, or are suffering from intra-abdominal pathology, or who have had opioid drugs or are in labor do not empty their stomachs efficiently and should always be treated as if they have a full stomach.
- Two common miss conceptions concerning the risk of aspiration on induction of general anesthesia need to be confronted are the surgical procedure is simple and quick, and therefore the anesthesia risk is slight and the stomach contents can be emptied via a nasogastric tube. The risk of aspiration during general anesthesia is unrelated to the length or complexity of the surgery and one never be certain that all of the secretions are aspirated.
- Strategies to prevent aspiration include decreasing gastric acidity by ranitidine and sodium citrate and decreasing gastric volume by metoclopramide and suctioning are successfully employed
- Regional anesthesia which maintain consciousness avoids aspiration.
- General anesthesia in patient with full stomach requires endotracheal intubation with a cuffed endotracheal tube. The cuff protects the lungs from soiling by gastric contents. The safest technique for introducing an endotracheal tube in this situation is called a rapid sequence induction (RSI or crash induction) using preoxygenation and cricoid pressure.
- It should be remembered that those patients at risk of aspiration on induction are similarly at risk on emergence.
- Initial management involves the recognition of aspiration by way of visible gastric contents in the oropharynx, hypoxia, increased inspiratory pressure, cyanosis, tachycardia or abnormal auscultation.
- Management includes head down position, suctioning airway, 100% oxygen administration, positive end expiratory pressure ventilation, rapid sequence induction ad intubation.
- A clinical decision between the anesthetist and surgeon must then be made on whether or not to proceed with surgery. This will depend on the underlying health of the patient, the extent of the aspiration, and urgency of the surgical procedure.
Last modified: Sunday, 20 November 2016, 8:36 AM