Letters, AANA Journal, June 1986

To the Editor. This letter is written in regard to the excellent case report "Reversal of narcotic-induced biliary spasm with nalbuphine hydrochloride" by Thomas McHugh, CRNA (December, 1985 AANA Journal). This case report clearly demonstrates one of several new and unique applications of nalbuphine (Nubain*). In addition, a previous study entitled "Outpatient anesthesia with nalbuphine hydrochloride" by Joseph Yanulevich, CRNA (August, 1983 AANA Journal) gave other applications of nalbuphine. The review article "Enkephalins and endorphins: the endogenous opiates" by Daniel Milloy, CRNA (December, 1982 AANA Journal) provides additional insight for the understanding of the relationship of various narcotic analgesics and man's own production of opiate-like substances. Having used nalbuphine extensively in our institution, we would like to offer other unique applications of nalbuphine that we have used or are investigating for possible use. Despite the presence of several commonly known drugs being classified in the agonist-antagonist category, nalbuphine appears to be unique in its cardiovascular profile. In a randomized double blind study in patients with acute myocardial infarction, Lee and co-workers compared the hemodynamic effects of nalbuphine and morphine.' Neither drug altered systolic arterial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, stroke index, stroke work index or pulmonary vascular resistance. These stable cardiovascular effects of nalbuphine are in contrast to the effects of other narcotic agonists-antagonists. Pentazocine (Talwin*) significantly increases mean aortic pressure, left ventricular diastolic pressure and mean pulmonary pressure in patients with coronary artery disease proven by catheterization.2 In a similar manner, butorphanol (Stadolr) produced increased cardiac index and mean pulmonary artery pressure in patients undergoing cardiac catheterization for the diagnosis of coronary artery disease. 3 The medical letter concludes that "the cardiovascular effects of nalbuphine are more like those of morphine than like those of pentazocine or butorphanol; some experts consider pentazocine and butorphanol to be contraindicated for patients with angina or myocardial infarction because they may aggravate myocardial ischemia by increasing the workload of the heart." 4 In patients with acute myocardial infarction, nalbuphine has an advantage over morphine, pentazocine and butorphanol of not producing hypotension.5 Since nalbuphine is characterized by good cardiovascular stability,( we have used it extensively as an analgesic for local sedation techniques. In high risk patients undergoing procedures such as insertion of cardiac pacemakers and cataract extractions we titrate nalbuphine intravenously in doses of 0.1-0.2 mg/kg. Since nalbuphine has a documented respiratory ceiling effect, respiratory changes are generally minimal in those patients that are frequently susceptible to respiratory depression. Additionally, we have found nalbuphine to provide good analgesia with a moderate degree of sedation in patients receiving regional anesthesia techniques. The analgesia provided by nalbuphine tends to make patients comfortable in regards to the tourniquet pain that is frequently experienced during intravenous regional (Bier Block) anesthesia techniques. During spinal or epidural anesthesia, nalbuphine provides good sedation without potentiating hypotension or causing significant respiratory depression that is often seen with pure agonist narcotics. For general anesthesia techniques, nalbuphine provides good analgesia when used as a narcotic base in balanced anesthesia or as a MAC reduction adjunct to potent inhalation anesthetic techniques. Clinical observation suggests that there is approximately a 0.3 MAC reduction when nalbuphine is used in balanced anesthesia techniques." As alluded to by McHugh in his case report, nalbuphine has several advantages over naloxone (Narcan*) as an antagonist of the respiratory depression produced by pure agonist narcotic in balanced anesthetic techniques. Consistent with the multiple opiate receptors concept pioneered by Martin, nalbuphine appears to be able to antagonize the respiratory depression caused by agonist narcotics while preserving and possibly potentiating the analgesia. ' 0 Hug and co-workers have recently reported on the use of nalbuphine as a respiratory depression antagonist following high-dose fentanyl techniques used for open-heart procedures.".1 In more conventional balanced anesthesia techniques utilizing fentanyl or oxymorphone (Numorphan*) as analgesics, we have used nalbuphine in a 0.1 mg/kg range to antagonize any residual respiratory depression. We have generally seen a dramatic improvement in the respiratory rate and tidal volume that lasts 2 to 3 times as long as that seen with naloxone. Hence, the possibility of renarcotization is highly unlikely.l 3 In contrast to naloxone, the patients receiving nalbuphine for antagonism of respiratory depression tend to remain comfortable without signs of reduction of analgesia.. 1314 ,