Efficient pain relief is crucial in primary life support to trauma victims. Acute pain makes breathing efforts inefficient and thereby adversely affects oxygenation. Persisting pain and anxiety also trigger the post-injury stress response and aggravate immunodepression. Uncontrolled post-injury stress response is a heavy risk factor for post-injury organ failure and trauma death.
Warning: prehospital opioid analgesics
Most trauma systems use opioid analgesics or pentazocine for prehospital parin-relief. These are potent analgesics, however with dangerous side-effects:
- suppression of protective airway reflexes
- gastric retention with vomiting, especially in hypotensive patients during rough evacuations
- respiratory depression
- reduced blood pressure, especially in hypovolemic patients
- narrow therapeutic range: risk of devastating accidental over-dosage in chaotic trauma scenarios.
Recommended: ketamine hydrochloride
Ketamine is a non-opioid potent analgesic that have been used for anesthesia for decades. As analgesic given in repeated sub-anesthetic doses (10% of anesthetic dose) the drug has several beneficial side-effects for prehospital life support:
- excellent pain-relief (superior to opioid analgesics) in small sub-anesthetic doses
- stimulates the sympathetic nervous system: moderate increase in cardiac output and systolic blood pressure even in hypovolemic patients
- does not affect airway reflexes
- does not depress the respiration
- wide therapeutic range: even accidental over-doses by a factor of 10 does not cause adverse side-effects.
TMC with the health authorities in Vietnam now conduct a controlled clinical trial of ketamine as compared to morphine for rural prehospital analgesia in trauma.