Respiratory depression after morphine in the elderly

Abstract

SummaryThe effects of intravenous morphine (10 mg/70 kg) on the ventilatory response to CO, were studied in two groups of subjects, young (18-29 years) and old (66-85 years), prior to elective surgery. In both groups morphine caused a signijcant depression of respiration as judged by a reduction in the slope of the COz response curve. a reduction in the calculated ventilation at an end tidal CO, tension of 7.3 kPa, a rise in resting end tidal C02 and a rise in the CO, threshold. There were no significant differences between the two groups in the changes produced by the drug, suggesting that acute respiratory depression after a single intravenous injection of morphine is similar in old and young people. Key wordsAnalgesics. narcotic; morphine. Measurement techniques; C 0 2 response.There is a widespread clinical impression that morphine causes greater respiratory depression in the old than in the young. Much experimental evidence fails to support this impression. Whilst breathing a C0,-enriched mixture after intravenous morphine administration, a group of elderly men achieved the same absolute ventilation as young men.' After intravenous or intramuscular morphine administration the changes in respiratory frequency u) and minute volume (p~) led to the conclusion that the aged did not possess the great sensitivity to morphine often attributed to them.2 After subcutaneous3 or intravenous4 morphine the changes in respiratory frequency, minute volume and end tidal COz tension (&'co2) were similar in young and old subjects.We have studied the effect of age on the ventilatory response to COz after intravenous administration of morphine by observing the changes in the C02 tension/ventilation curve and the calculated ventilation at a PE'CO, 7.3 kPa (v7.3). In addition, we observed the changes in the resting PE'co, and the 'CO, threshold' which is the level of PE'co, at which ventilation begins to increase from the basal level. MethodsTwo groups of 12 patients were studied. One Morphine in the elderly 91 1 group of six males and six. females was aged 66-85 years (mean 76 years) and the other group of six males and six females was aged 18-29 years (mean 25 years). The mean weight of the older group was 59 kg (43-85 kg) and the mean weight of the young group was 69 kg (51-86 kg). All patients were free from overt cardiorespiratory disease and gave informed consent for the study which was approved by the hospital ethical committee. Each patient was studied whilst lying comfortably on a trolley in the anaesthetic room prior to elective surgery. All subjects had been starved for at least 8 hours and had received no other drug. The measurement of ventilatory response to CO, was based on the method described by Read.5 The subject rebreathes into a small bag containing C02 at a partial pressure close to that of mixed venous blood. The progressive rise in Pco, within the bag stimulates respiration and the slope of the ventilation curve reveals information about the sensitivity of the respiratory centre.Each subject wore a nose cli...

Issues in Geriatric Orthopedic Anesthesia

“…75,76 The goal for postoperative analgesia for patients undergoing TJA is maximizing analgesia and minimizing sedation so that patients can participate in physical therapy after surgery. Opioid use should be minimized, as these agents increase the risk of several adverse reactions including respiratory depression, falls, and delayed enteral feeding in patients over 70 years old.…”

“…Opioid use should be minimized, as these agents increase the risk of several adverse reactions including respiratory depression, falls, and delayed enteral feeding in patients over 70 years old. 75 Medications that are commonly used in multimodal therapy include low-dose ketamine, 76 gabapentin, pregabalin, acetaminophen, a-agonists, and nonsteroidal anti-inflammatory agents. 77,78 Regional techniques are important components of multimodal analgesia.…”

“…75,79,80 Epidurals provide excellent analgesia but often limit ambulation, require an indwelling urinary catheter, and prevent timely institution of VTE prophylaxis. Peripheral nerve blocks and catheters provide excellent analgesia, but continuous peripheral nerve catheters may result in a higher incidence of falls than single-shot blocks.…”

Effects of Anesthetics, Sedatives, and Opioids on Ventilatory Control

“…Respiration in younger and older humans seems to be depressed equally by intravenous morphine but it has been described that older adults tend to have more apneas and periodic breathing (17,119).…”

Douleur sévère et morphine aux urgences chez le patient âgé

“…Mais si on note une meilleure efficacité des opioïdes pour une même dose, leur toxicité tend à s'accroître parallèlement. Les bradypnées semblent plus fré-quentes sous morphine parentérale que chez le patient jeune [29]. Le plus souvent, il s'agit plutôt d'apnées obstructives qui surviennent en dehors de toute diminution de la fréquence respiratoire.…”