Donald C. Tyler

The dose response of caudal morphine in children

The authors compared the duration of analgesia and the frequency of side effects of three doses of caudal epidural morphine in children aged 1.2-7.9 yr. Caudal catheters were inserted in 32 children, randomly assigned to receive 0.033 mg.kg-1, 0.067 mg.kg-1, or 0.10 mg.kg-1 of preservative-free morphine for analgesia after major surgical procedures below the diaphragm. The first dose of caudal morphine was mixed with 0.25 ml.kg-1 of 1% lidocaine to confirm correct caudal catheter placement. By assessment of periodic pain scores and the time intervals between administration of caudal morphine and the recurrence of pain, the authors found that the mean (+/- SD) duration of analgesia was significantly longer after 0.10 mg.kg-1 (13.3 +/- 4.7 h) than after either 0.033 mg.kg-1 or 0.067 mg.kg-1 (10.0 +/- 3.3 and 10.4 +/- 4.2 h, respectively) (P less than 0.02). The frequency of vomiting, pruritus, and urinary retention was similar in each group. Vomiting was less common in patients who had nasogastric drainage than in patients who were fed soon after surgery (P less than 0.05). Delayed respiratory depression occurred in one child after 0.10 mg.kg-1 of caudal morphine. Caudal morphine, 0.033-0.10 mg.kg-1, provided prolonged analgesia in children. The authors recommend 0.033 mg.kg-1 of caudal morphine as an initial dose for children.

Caudal morphine for postoperative analgesia in children: a comparison with caudal bupivacaine and intravenous morphine.

We compared the efficacy, duration, and side effects of preservative-free morphine injected into the caudal space in children, with caudal bupivacaine and with intravenous morphine administration for relief of postoperative pain. Forty-six children, ages 1-16 yr, were randomly assigned to receive intravenous morphine (control group), caudal bupivacaine (0.25%, 1 ml/kg), or caudal morphine (0.5 mg/ml, 0.1 mg/kg). In half the patients given caudal morphine, the morphine was mixed with a dose of lidocaine adequate to produce sacral analgesia, to confirm correct caudal injection of the morphine. Caudal injections were performed at the end of surgery. Time until the first required postoperative intravenous morphine dose was recorded for each patient. The duration of analgesia was significantly greater with caudal morphine (median 12 hr, P less than 0.02) than with caudal bupivacaine (median 5 hr), and both were greater than with intravenous morphine in control patients (median 45 min). Urinary retention, pruritus, and nausea appeared with slightly greater frequency in the caudal morphine group, but no delayed respiratory depression occurred. Caudal morphine (0.5 mg/ml, 0.1 mg/kg) provided 8-24 hr of analgesia in children without a significantly greater incidence of side effects than caudal bupivacaine or intravenous morphine.

Determining optimum operating room utilization

Economic considerations suggest that it is desirable to keep operating rooms fully used when staffed, but the optimum utilization of an operating room (OR) is not known. We created a simulation of an OR to define optimum utilization. We set operational goals of having cases start within 15 min of the scheduled time and of having the cases end no more than 15 min past the scheduled end of the day. Within these goals, a utilization of 85% to 90% is the highest that can be achieved without delay or running late. Increasing the variability of case duration decreases the utilization that can be achieved within these targets.

Morphine infusion after pediatric cardiac surgery

After cardiac surgery, 44 children received a continuous iv infusion of morphine sulfate at 10 to 30 Mg/kg-h. During weaning from assisted ventilation and during spontaneous ventilation serum morphine levels less than 30 ng/ml were not associated with elevated Paco2. Five extubated patients breathed

Positive end-expiratory pressure: A review

Current treatment of respiratory disease relies on the use of positive end-expiratory pressure (PEEP) during mechanical ventilation. To use this form of therapy, one applies positive pressure to the lung while the patient exhales; PEEP can be applied with the patient breathing spontaneously or with the patient being mechanically ventilated. Use of the term PEEP implies that the pressure is the important therapeutic modality; in actuality, it is a change in resting lung volume that is important. The beneficial effect of PEEP in improving oxygenation is quite clear, but complications may arise out of the physiologic responses of the patient to ventilation with end-expiratory pressure. The purpose of this review is to provide background information to allow a better understanding of the physiologic consequences of PEEP.

Coma scale for use in brain-injured children

The association between admission coma score and eventual outcome was assessed using a coma scale developed for children with a variety of central nervous system injuries. As opposed to the Glasgow coma scale, this scale does not demand assessment of verbalization, and thus can be applied to the preverbal or previously intubated child. Cortical function is graded from 6 (purposeful, spontaneous movements) to 0 (flaccid), and brainstem function is graded from 3 (intact) to 0 (absent and apneic). Maximum total score is 9.In 91 children treated for intracranial hypertension, the association was moderately good. The scale was better in predicting the outcome of patients with hypoxic encephalopathy and head trauma than that of patients with Reyes syndrome, meningitis, or encephalitis. No child with a score of less than 3 survived in spite of intensive therapy. Most of these children were flaccid with depressed or absent brainstem reflexes. No child with flaccidity on admission survived.

Respiratory depression after low-dose caudal morphine

PurposeTo report a case of respiratory depression after a small dose of caudal morphine administered to a 15-mo-old child.Clinical featuresA 15 mo, 9.8 kg boy underwent ureteral reimplantation with general endotracheal anaesthesia and 10 ml bupivacaine 0.25% (2.5 mg · kg−1). Ninety minutes after the bupivacaine, 0.4 mg (1 mg · ml−1, 0.4 ml, 0.04 mg · kg−1) preservative-free morphine was injected after negative aspiration. Slighly more than two hours after caudal morphine, the patient became lethargic and developed decreases in oxygen saturation (to 62%) without change in heart rate or respiratory rate. Intravenous naloxone 0.1 mg (0.01 mg · kg−1) markedly improved his level of consciousness. Racemic epinephrine was administered for treatment of coincident stridor. The patient required 11 hr continuous naloxone infusion (0.001–0.002 mg · kg−1 · hr−1) in the intensive care unit. He was discharged on the second postopertive day without further complication.ConclusionRespiratory depression can occur in children greater than one year of age, even when small doses of caudal morphine are used. Decreased arterial oxygen saturation and lethargy are important heralds. A normal respiratory rate despite substantial hypoxaemia argues that pulse oximetry (without supplemental oxygen where possible) has a clear advantage over impedance pneumography for electronic monitoring.RésuméObjectifPrésenter un cas de dépression respiratoire consécutive à l’injection caudale d’une petite dose de morphine.Éléments cliniquesUn jeune garçon âgé de 15 mois était opéré pour une réimplantation urétérale sous anesthésie générale endotrachéale combinée à de la bupivacaïne 0,25% 10 ml (2,5 mg · kg−1). Quatre-vingt-dix minutes après la bupivacaïne, de la morphine 0,4 mg (1 mg · ml−1, 0,4 ml, 0,04 mg · kg−1) était injectée après un test d’aspiration négatif. Un peu plus de deux heures après l’administration caudale de morphine, le patient devenait léthargique et sa saturation en oxygène diminuait (à 62%) sans que sa fréquence cardiaque et respiratoire n’ait changé. L’injection intraveineuse de naloxone 0,1 mg (0,01 mg · kg−1) améliorait considérablement son niveau de conscience. De l’épinéphrine racémique était aussi administrée pour traiter un stridor surajouté. Le patient a eu besoin d’une perfusion continue de naloxone (0,001–0,002 mg · kg−1 · h−1) pendant 12 heures à l’unité des soins intensifs. Il était libéré deux jours après l’opération sans autres complications.ConclusionUne dépression respiratoire peut survenir chez des enfants de plus d’un an, même lorsque les doses de morphine administrées sont minimes. La baisse de la saturation en oxygène et la léthargie constituent des signes importants. Le maintien d’une fréquence respiratoire normale malgré une hypoxémie importante plaide en faveur de l’oxymétrie de pouls (à l’air ambiant lorsque c’est possible) comme moniteur électronique préférablement à la pneumographie par impédance.

Epidural opioids in children.

Experience with spinal opioids in children is limited but is expanding. Anatomy, pharmacology, technique, and results are reviewed. Complications and side effects are described.

Patient-controlled analgesia in adolescents

Patient-controlled analgesia (PCA) is a method of administering narcotics in which the patient activates a machine to administer a small bolus of narcotic. In the first year of PCA use in our hospital, 26 patients used PCA. We suggest a dose volume of 0.015 mg/kg/dose and a 4-hour limit of 0.25 mg/kg/4 hr, with a lock-out of 10 minutes. Patients used approximately equivalent amounts to standard parenteral narcotics, but there was a wide interpatient variability in the amount of narcotic used. No clinical respiratory depression was noted, and patients did not titrate themselves to complete analgesia. PCA is an effective means of pain control in adolescent patients.

Pharmacology of pain management

This article examines the clinical pharmacology of opioids, nonsteroidal anti-inflammatory drugs, and tricyclic antidepressants with reference to their use in treating pain in children.