In the March 2007 issue of Canadian Family Physician, Dr Minty and colleagues discuss the advantages and safety of intrathecal narcotics (ITN) for labour pain and suggest this as a technique that all family physicians could consider adding to their basic skill sets.1 Though both the Society of Rural Physicians of Canada and the Canadian Anesthesiologists’ Society support family physicians in the practice of anesthesia, both societies require that physicians undergo appropriate training. As a GP-anesthetist whose practice is limited almost exclusively to anesthesia, I have concerns about the safety of the use of this technique by those without additional training and experience in anesthesia.
This article points out that “mini-spinals” can be performed safely and provide excellent analgesia to women during labour. For this to occur, however, one must be familiar with the pharmacology of the medications delivered intrathecally, as well as be able to anticipate and deal with any complications that might arise. Although family physicians are well suited to performing lumbar punctures, it is the administration and management of ITN that requires specialized skills. This is why additional training in anesthesia becomes mandatory.
Dr Minty and colleagues propose doses of ITN that are greater than or equal to what many anesthetists would give during surgical anesthesia for a cesarean section. A safety issue not discussed in the article is that the peak concentration of spinal morphine occurs 8 hours after administration and the duration of spinal morphine might be as long as 24 hours.2–4 Additionally, peak respiratory depression has been found to occur between 3.5 and 7.5 hours after administration.5 Those not familiar with this route of drug administration might cease appropriate monitoring once 4 hours have passed, as suggested in the article. It is because of this prolonged duration of intrathecal morphine that all anesthesia departments in which I have worked have specific protocols for dealing with side effects, most notably respiratory depression, in patients who have received morphine intrathecally. At our hospital, for the first 12 hours following a dose of intrathecal morphine, the only physician who can order additional narcotic or sedative medications is the anesthetist, as he or she is the one familiar with this route of administration.
Another safety concern not addressed by this article is that of administering intrathecal bupivacaine in combination with fast-acting narcotics. Even in low doses, this can result in profound hypotension and has also been implicated in causing uterine hypertonicity and thus fetal bradycardia.6,7 Again, those who have not had the training and experience to deal with these uncommon yet serious side effects should not be performing the procedure.
Dr Minty and colleagues point out that ITN have a valuable role to play in the provision of analgesia for women during labour. In my opinion, however, if epidural services are not available due to the lack of an anesthetist, then ITN should not be an option. Though performance of the procedure is within the realm of most family physicians, management of the pharmacology of ITN requires a specialized skill set. Just as a non-anesthetist family physician would not be expected to perform spinal anesthesia for a cesarean section, we should not encourage them to perform mini-spinals for labour analgesia.
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