Respiratory depression and spinal opioids

Abstract

Administration of epidural and intrathecal opioids may provide excellent postoperative analgesia, but a minority of patients will suffer dangerous respiratory depression. This review discusses the detection and measurement of respiratory depression and summarizes the relevant literature as it pertains to epidural and intrathecal opioid administration. The respiratory depressant effects and pharmacokinetics of spinal opioids are reviewed. The clinical implications and areas of future investigation are discussed.

Définitions de la “dépression respiratoire” de l’analgésie postopératoire réalisée avec de la morphine intrathécale : une revue documentaire

“…104 While defining RD with bradypnea is superior to no definition whatsoever, it is considered to be an inadequate index of ventilatory depression. 4,10,15,27,81,[113][114][115] RR does not necessarily correlate with ITM dose, hypoxemia or depressed ventilatory response to CO 2 -stimulation. 9,27 Patients may even be hypoxemic 4 or hypercapnic with a normal RR.…”

“…Also, opioid-induced RD is confounded by hypoventilation and hypoxemia from midazolam sedation, general anesthesia and surgery itself. 4 Some studies used iv patient-controlled analgesia after ITM, 36,37 which may also confound ITM-induced RD. Importantly, "respiratory depression" is not a term with a clear or standard definition.…”

“…[2][3][4][5] Intrathecal morphine (ITM) was the opioid involved in many of the cases of delayed RD, 6-8 a serious but rare complication. ITM produces a dose-related analgesia and RD 2-4,9-14 via separate receptor mechanisms.…”

“…15 Peak RD with ITM occurs between 3.5 to 12 hr postinjection. 3,4,8,9,11,16,17 Large surveys report the incidence of RD after ITM ranging from 0.03% 18 up to 7%. 7 Some believe ITM is underused for routine postoperative analgesia 19 due to the risk of delayed RD.…”

Epidural lidocaine with sufentanil and epinephrine for abdominal hysterectomy under general anaesthesia: respiratory depression and postoperative analgesia

“…7 Though there have been no reports of delayed respiratory depression following epidural sufentanil, evidence of early respiratory depression remains controversial. 3 No previous studies have examined the interaction of epidural opiates and general anaesthesia on respiratory function. As many patients may receive their first dose of epidural opiate either during anaesthesia or in the early recovery phase, such an interaction may be clinically important.…”