Postoperative use of epidurally administered morphine in children and adolescents.

Epidurally administered narcotics are increasingly used to provide relief of pain in adults after major surgical procedures. This report describes the use of epidurally administered morphine for postoperative analgesia in nine pediatric patients after 15 major surgical procedures. The mean dose of morphine was 0.12 +/- 0.03 mg/kg of body weight, and the mean duration of analgesia per dose was 10.8 +/- 4.0 hours. Catheters remained in place for a mean duration of 50.3 +/- 16.0 hours. Increasing the dose of morphine to more than 0.1 mg/kg did not prolong the duration of analgesia but it did increase the frequency of side effects. No complications from placement of the catheter and no serious side effects were encountered. The postoperative requirements for narcotics were significantly less in the patients who received morphine epidurally than in those who received narcotics parenterally. Epidurally administered morphine can provide reliable postoperative analgesia in pediatric patients. The potential benefits include improved quality of pain relief at low total requirements, improved pulmonary function, and early ambulation.

AANA journal course: update for nurse anesthetists--current concepts in pediatric resuscitation.

The evolution of the current recommendations for pediatric cardiopulmonary resuscitation have slowly evolved following the development of cardiopulmonary resuscitation techniques for the adult patient. Anatomical and physiological differences along with the pathophysiology of pediatric cardiopulmonary arrest mandate special consideration when approaching pediatric cardiopulmonary resuscitation.

Transcutaneous O2 and CO2 monitoring of neurosurgical patients: detection of air embolism.

Transcutaneous oxygen tension (PtcO2) and transcutaneous carbon dioxide tension (PtcCO2) were monitored in 60 patients undergoing neurosurgical procedures. Twenty-six patients were in the sitting position and underwent routine monitoring for air embolism. Seventeen episodes of air embolism were diagnosed by precordial Doppler ultrasound or transesophageal echocardiography, and the PtcO2 decreased early during the course of each episode. The mean PtcO2 decrease was 48 +/- 35 mmHg. During ten episodes the end-tidal carbon dioxide tension (PETCO2) decreased but only after the PtcO2 had already begun to decrease. PtcCO2 increased during air embolism but PETCO2 changes preceded the change in PtcCO2 by 1-2 min. Transcutaneous values during air embolism were verified with simultaneous arterial blood gas values during six air embolism episodes. A strong positive correlation was found between transcutaneous and arterial oxygen and carbon dioxide tensions. Correcting the PtcCO2 by the patient's baseline PtcCO2/PaCO2 ratio, PtcCO2 monitoring correctly reflected hypocarbia, normocarbia, and hypercarbia in 92% of the cases. PtcO2 monitoring was useful in detecting venous air embolism and may respond sooner than PETCO2. PtcCO2 monitoring was not useful as an early detector of air embolism.

Neonatal pneumopericardium: analysis of ventilatory variables.

Case reports of all infants admitted to the NICU from 1971 to 1982, who developed a pneumopericardium (PPC) while receiving intermittent positive-pressure ventilation, were reviewed in order to determine those variables of assisted ventilation associated with the occurrence of PPC. Of 19 infants seen during the 11-yr period, 16 had respiratory distress syndrome (RDS) and 3 had other forms of severe pulmonary disease. Mean birth weight was 1720 g, gestational age 32 wk, and age at occurrence 59 h. Peak inspiratory pressure (PIP) (mean 32 cm H2O), inspiratory time (IT) (0.74 sec), and mean airway pressure (MAP) (mean 17 cm H2O) were significantly elevated just before occurrence of the PPC, compared with values 6 h previously. PEEP (mean 3.8 cm H2O), ventilator rate (mean 40/min), PaCO2 (mean 41 torr), P(A-a)O2 (mean 443 torr), and inspired oxygen concentration (FIO2, 0.77) were unchanged. MAP was significantly lower (mean 11 cm H2O) 6 h after the event compared with just before (mean 14 cm H2O) in infants who died, suggesting that lowering airway pressure does not improve survival. These data indicate that high PIP, prolonged IT and elevated MAP are associated with the development of PPC. MAP provides a composite of pressure transmitted to the airways and may be the more useful index in preventing barotrauma and pulmonary air leak.

Transesophageal echocardiography and transcutaneous O2 and CO2 monitoring for detection of venous air embolism.

The sensitivities of current monitoring methods for detection of air embolism were compared in eight anesthetized dogs. Air was infused at controlled rates of 0.001 and 0.005 ml X kg-1 X min-1 for 1 min; 0.01, 0.05, 0.1, 0.2, and 0.4 ml X kg-1 X min-1 for 6 min; and 5 ml X kg-1 bolus injection. Based on the mean quantity of air infused to elicit a positive response, the monitors could be placed into three significantly different sensitivity groups. Transesophageal echocardiography (TEE) and precordial Doppler ultrasound were the most sensitive monitoring methods detecting 0.19 and 0.24 ml X kg-1 of air, respectively. TEE detected air during six infusions in which the Doppler failed to do so. The next most sensitive group of monitoring methods included pulmonary artery pressure (PAP), end-tidal CO2 (PETCO2), arterial oxygen tension (PaO2), and transcutaneous oxygen tension (PtcO2). The mean quantity of air infused to elicit a positive response in this group of monitors ranged from 0.61 to 0.76 ml X kg-1. The response of PtcO2, PaO2, PETCO2, and PAP equally reflected the quantity of air infused. The least-sensitive group of methods included arterial and transcutaneous carbon dioxide tension and systemic arterial blood pressure. These data indicate that TEE is more sensitive than Doppler ultrasound and that PAP, PETCO2, and PtcO2 are equally sensitive in detecting venous air embolism in the dog.

High-frequency, small-volume ventilation during thoracic surgery.

Surgical conditions during conventional mechanical ventilation (CMV) and pulmonary gas exchange were compared with those during high-frequency ventilation (HFV) in 24 patients undergoing anesthesia for intrathoracic surgery. HFV at an oscillatory frequency of 3 Hz and a delivered gas volume of 1.3-1.9 ml/kg provided excellent surgical conditions for peripheral lung procedures. However, surgical conditions for procedures on the major airways or mediastinal structures were unsatisfactory during HFV. Adequate pulmonary gas exchange was achieved with HFV when the chest was open. Further evidence is presented for expiratory flow limitation during HFV. Expiratory flow limitation seems to occur particularly in patients with chronic obstructive airway disease, leading to increased lung volume. Currently, the authors do not recommend HFV for routine use during anesthesia for thoracic surgery.

Nitrous oxide analgesia in a pediatric emergency department.

Nitrous oxide (N2O) has been shown to be an effective analgesic in adult medical outpatients, yet no prospective studies of its use in the pediatric medical outpatient exist. Thirty-four children requiring laceration repair were randomly assigned to one of two treatment groups: 30% N2O/70% O2 or a placebo, 100% O2. Pain behavior, using the observer-scored Children's Hospital of Eastern Ontario Pain Scale, was assessed by double-blind techniques, before and during the laceration repair. Less pain behavior was seen in children less than 8 years old who received the N2O mixture than in those receiving the placebo. In patients 8 or more years old who received N2O, there was a significant improvement in the second evaluation as compared with those receiving only O2 during the procedure (P less than .05). There also was a smaller increase in pain behavior, from the first to the second evaluation, in those receiving N2O (P less than .05). No side effects were encountered. The authors conclude that continuous N2O inhalation is an effective and painless analgesic in children for outpatient procedures. More effective analgesia will likely occur with 40% to 50% N2O, although these concentrations remain to be studied in pediatric outpatients.

Calculation of mean airway pressure during mechanical ventilation in neonates.

Mean airway pressure (Paw) calculated by 4 methods was compared with measured Paw, using 833 observations on 16 infants requiring constant-flow, pressure-limited mechanical ventilation. Measured Paw was most accurately predicted by determining a waveform constant for each infant every 12 h, and then using the waveform constant in a general Paw equation for the ensuing 12 h. However, this method is impractical for clinical use. A square-waveform equation more accurately predicted Paw than did triangular or sine-like waveform equations. Because there was considerable interindividual variation in the accuracy of all methods, due to different individual respiratory waveforms and waveform constants, Paw should be measured and not calculated.

Low-dose sufentanil as a supplement to halothane/N2O anaesthesia in infants and children.

Sufentanil as a supplement to halothane/N2O anaesthesia was evaluated in 32 unpremedicated infants and children age 6 months to 9 yr undergoing elective orthopaedic surgery. Patients were randomly assigned in a double-blind manner to receive one of four intravenous supplements: placebo, sufentanil 0.5, 1.0 or 1.5 micrograms.kg-1. Systolic arterial pressure (SAP), heart rate (HR) and end-tidal halothane concentration were recorded before and after induction, supplement administration, tracheal intubation, incision and every 15 min during the procedure. Venous catecholamine samples were obtained before and after incision. A pain score was assigned to the patients in the postanaesthesia care unit (PACU). Sufentanil at all three doses prevented increases in SAP and HR with intubation and incision, provided superior pain relief in the PACU and did not prolong wake-up time. Sufentanil 1.0 and 1.5 micrograms.kg-1 allowed for a reduction in the halothane requirements. Sufentanil 1.5 micrograms.kg-1 was associated with lower catecholamine levels than in the placebo group following incision. Sufentanil supplementation at 1.0 and 1.5 micrograms.kg-1 was associated with bradycardia and/or hypotension during induction and an increased incidence of vomiting during the first 24 hours postoperatively. One patient in the sufentanil 1.0 micrograms.kg-1 group whose surgical time was less than 45 min exhibited respiratory depression in the PACU requiring narcotic reversal. In conclusion, sufentanil 0.5 micrograms.kg-1 improved immediate postoperative pain relief and is acceptable as a supplement during halothane anasethesia in infants and children. The associated side effects of larger doses of sufentanil (1.0 and 1.5 micrograms.kg-1) make their use as a supplement to halothane anaesthesia unacceptable.

Comparison of the hemodynamic and echocardiographic effects of sufentanil, fentanyl, isoflurane, and halothane for pediatric cardiovascular surgery.

Sufentanil, fentanyl, halothane, and isoflurane were compared as sole anesthetic agents in 48 infants and children aged 6 months to 9 years, undergoing repair of congenital heart defects. Patients were randomly assigned to receive sufentanil, 20 microg/kg, fentanyl, 100 microg/kg, isoflurane, 1.6%, or halothane, 0.9%, along with pancuronium, 0.08 mg/kg, for induction and maintenance of anesthesia. Cardiovascular function was measured by echocardiography prior to induction, postinduction, and postintubation. Systemic arterial pressure and heart rate were also recorded. Left ventricular ejection fraction (LVEF) decreased following induction with each agent: sufentanil 9%, fentanyl 9%, isoflurane 4%, and halothane 8%. Following intubation LVEF increased in the sufentanil, fentanyl, and isoflurane groups, but LVEF remained 13% below baseline values in the halothane group. Five of the 12 patients in the halothane group had a LVEF less than 55%. Arterial pressure immediately prior to bypass was significantly less than baseline in each group; however, arterial pressure was higher in the narcotic groups during isolation and cannulation of the great vessels. It is concluded that halothane, 0.9%, used as an induction agent in infants and children undergoing cardiac surgery causes a clinically significant decrease in LVEF. Based on the echocardiographic data, sufentanil, fentanyl, and isoflurane as used in the present study do not have a clinically significant effect on cardiac function and may offer an advantage to infants and children with marginal cardiovascular reserve.

Selective bronchial intubation in infants with lobar emphysema: indications, complications, and long-term outcome.

Thirteen infants underwent selective intubation of a mainstem bronchus (SBI) for lobar emphysema of varying etiologies. Seven infants had pulmonary interstitial emphysema (PIE) with lobar hyperinflation secondary to hyaline membrane disease and mechanical ventilation. Six of these improved with SBI and five maintained permanent resolution upon cessation of SBI. Two infants with localized areas of emphysema who were subsequently shown to have histologic evidence of bronchopulmonary dysplasia had unsuccessful SBI. SBI was also unsuccessful in permanently resolving congenital lobar emphysema although temporary collapse of the affected lobe occurred during SBI. Complications including hypoxia, bradycardia, right upper lobe atelectasis, pneumonia, and additional air leaks occurred during SBI in six cases. Follow-up xenon ventilation scans in four infants in whom SBI was successful revealed normal ventilation of the previously diseased lobes. SBI can be a useful alternative to surgical excision of the affected lobe in patients with localized lobar hyperinflation secondary to PIE. SBI is generally unsuccessful in permanently correcting congenital lobar emphysema, nor should it be used when chronic diffuse parenchymal damage is present.

Postnatal diuresis and respiratory distress syndrome in infants receiving mechanical ventilation.

Measurements of body water homeostasis and pulmonary function were obtained in 24 infants with respiratory distress syndrome requiring mechanical ventilation during the first five days of life to determine the relationship of diuresis to improvement in pulmonary function. Initial diuresis (output intake ratio greater than 0.8) occurred at 24 hours, maximum diuresis (output intake ratio greater than or equal to 1.6) at 40 hours, and initial improvement in pulmonary function (fall in AaDO2 greater than 50 mm Hg) at 48 hours. Urine flow rates over four-, eight-, or 12-hour periods were quite variable and correlated poorly with improvement in pulmonary function. Reduction in body weight was a more accurate indicator of total changes in body water than urine output, output intake ratio, or fractional excretion of sodium. Although there was a temporal relationship of loss of body water and improvement in pulmonary function by analysis of means, no cause-and-effect relationship could be found on a case-by-case analysis. Five of 24 infants demonstrated improvement in pulmonary function prior to diuresis or reduction in body weight. Nine infants had a diuresis more than 24 hours prior to pulmonary improvement, and two infants had a diuresis without pulmonary improvement during the five-day study period. These data indicate that factors other than body water are associated with improvement in pulmonary function in infants with respiratory distress syndrome.