Pain management and sedation in the pediatric intensive care unit

Several situations arise in the PICU patient that require the administration of drugs for sedation and analgesia. A "cookbook" approach is impossible because of the diversity of patient and clinical scenarios. When amnesia is required, these authors prefer a continuous infusion of a benzodiazepine such as midazolam or lorazepam. Although the majority of clinical experience has been with midazolam, lorazepam either by bolus dose or continuous infusion offers a cost-effective alternative. When analgesia is required, the addition of a continuous infusion of narcotic or the use of a PCA device in the older patient should prove effective. Although fentanyl is frequently chosen, morphine is an effective and cost-effective alternative for patients with stable cardiovascular function. The synthetic narcotics are recommended for neonates, especially following cardiac surgical procedures and those at risk for pulmonary vasospasm. Narcotics may also be used for the treatment of agitation in those situations that do not necessarily require analgesia. Our clinical experience suggests that narcotics may be more effective for sedation than benzodiazepines in children less than 1 year of age. When the above agents fail to be effective or are associated with cardiovascular depression, alternatives may include ketamine or pentobarbital. Ketamine may be useful for the unstable patient or those with a bronchospastic component to their disease process. We have found pentobarbital to be effective when the combination of benzodiazepines and narcotics fails to provide the desired level of sedation. Aside from these techniques, regional anesthesia may offer a more effective means of controlling pain in the PICU patient. These techniques may be effective when parenteral narcotics are inadequate or lead to undesired effects. Although most commonly used for postoperative analgesia, their use in patients with pain from other causes (e.g., multiple trauma) may be indicated, especially when parenteral narcotics may interfere with respiratory function or the ongoing assessment of the patient's mental status.

General anesthesia by mask with spontaneous ventilation during brief laparoscopic inspection of the peritoneum in children

We prospectively examined the cardiorespiratory changes seen with general anesthesia by mask with spontaneous ventilation during brief laparoscopic inspection of the peritoneum in children. Anesthesia consisted of isoflurane in 50% oxygen/air and a caudal epidural block. The patient was allowed to ventilate spontaneously without assistance. Baseline measurements of heart rate, systolic/diastolic blood pressure (BP), end-tidal CO2 (PETCO2), tidal volume, respiratory rate, and oxygen saturation were recorded every 1 min for 5 min before the start of laparoscopy and every minute during the laparoscopic procedure. A total of 20 patients were enrolled in the study, ranging in age from 15 to 80 months (mean 40.8 months) and in weight from 10.5 to 27 kg (mean 15.9 kg). The length of the laparoscopy varied from 3 to 18 min (mean 6.9 min). No significant changes (increase or decrease of 20% from baseline) of heart rate or BP occurred. Oxygen saturation remained at 98%-100% throughout the procedure in all patients. The baseline tidal volume before the start of laparoscopy was 6.27 +/- 1.9 mL/kg and increased to 7.3 +/- 2.2 mL/kg during laparoscopy (p = 0.01). The baseline respiratory rate was 27.7 +/- 7.0 breaths/min and increased to 33.5 +/- 7.2 breaths/min during laparoscopy (p = 0.0001). PETCO2 increased from a baseline value of 37.5 +/- 6.5 to 44.6 +/- 6.8 mm Hg (p = 0.0001). The increase in PETCO2 was 10 or greater in 3 patients and exceeded 50 mm Hg in 3 patients, with a maximum value of 66 torr.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative cardiopulmonary resuscitation in the prone position

Cardiopulmonary resuscitation (CPR) occasionally is necessary in the operating-room setting. In such instances, it may be difficult to perform CPR if the patient is in the prone position. Although the supine position is optimal for CPR, it may not be feasible because of the risks of damage to craniospinal structures. The authors present the case of a 12-year-old boy who had cardiac arrest during spinal fusion. Successful CPR was performed with the patient in the prone position, with the use of "reversed precordial compressions," and the patient was resuscitated despite 7 minutes of asystole. Effective cardiac output was maintained and was confirmed by systolic blood pressure readings of 80 to 90 mm Hg on both the arterial catheter waveform and the noninvasive blood pressure cuff, by a waveform and the reading on the pulse oximeter, and by the presence of end-tidal carbon dioxide.

Noninvasive monitoring of end-tidal CO2 via nasal cannulas in spontaneously breathing children during the perioperative period

OBJECTIVE

To determine the correlation between end-tidal CO2 and PaCO2 values measured via nasal cannulas in spontaneously breathing children during the perioperative period.

DESIGN

Prospective evaluation.

SETTING

Pediatric intensive/intermediate care unit in a tertiary care referral center.

PATIENTS

Thirty postoperative surgical and trauma patients aged < or = 18 yrs (average age 7.8 yrs [range 6 months to 16 yrs] and average weight 28.3 kg (range 8.5 to 69).

MEASUREMENTS AND MAIN RESULTS

Spontaneously breathing, nonintubated patients with an arterial cannula in place were selected for study. End-tidal CO2 was sampled from nasal cannulas by a sidestream aspirator and was estimated by infrared spectroscopy. The difference between PaCO2 and end-tidal CO2 was compared using linear regression analysis. A total of 55 blood gas measurements were obtained on the 30 patients. The PaCO2 to end-tidal CO2 gradient was < or = 4 torr in 54 of the 55 samples. The mean PaCO2 was 39.5 +/- 3.3 torr (5.27 +/- 0.44 kPa) with a mean end-tidal CO2 value of 39.7 +/- 3.8 torr (5.29 +/- 0.51 kPa). Linear regression analysis of arterial vs. end-tidal CO2 yielded a slope of 0.992 and p = .0001.

CONCLUSIONS

End-tidal CO2 measurement by infrared spectroscopy provided an accurate estimation of PaCO2 in this patient population. Its use may limit the need for invasive monitoring and/or repeated arterial blood gas analysis.

Hypoplastic left heart syndrome: anesthetic care prior to transplantation or surgical palliation

Hypoplastic left heart syndrome is the most common lethal cardiac defect in neonates. Options for treatment include cardiac transplantation and surgical palliation. When cardiac transplantation is chosen as the preferred option, a considerable delay may occur until a suitable donor is available. During this time, anesthetic care may be required for various surgical procedures. Associated anomalies seen in these infants and the anesthetic implications imposed by the abnormal cardiac anatomy are discussed.

Outpatient therapy of iatrogenic drug dependency following prolonged sedation in the pediatric intensive care unit

The authors present their clinical experience with the oral administration of lorazepam, methadone, and pentobarbital to prevent or treat withdrawal symptoms following prolonged sedation in the PICU patient. The 3 patients presented required prolonged sedation for mechanical ventilation. Different agents were used for sedation in the 3 patients including intravenous fentanyl, midazolam, and pentobarbital. The switch to oral agents must take into consideration the differences in potency, half-life, and oral bioavailability between the agents. The authors discuss the appropriate conversion factors for opioids, benzodiazepines, and barbiturates. The switch to oral administration eliminated the need for intravenous access in the 3 patients and allowed for earlier discharge home. All 3 patients were discharged home on an oral, taper schedule. Such an approach may lead to earlier home discharge thereby improving the patient's quality of life as well as saving health care dollars.

Complications of autotransfusion with salvaged blood

As a means of limiting homologous transfusions, many centers are using autotransfusion devices during the postoperative period. Although their use may limit the risks associated with homologous blood administration, various adverse effects have been reported including sepsis, disseminated intravascular coagulation, and renal insufficiency. The authors present the case of a 9-year-old girl who developed acute cardiorespiratory dysfunction after reinfusion of salvaged blood. The use of autotransfusion devices and the probable mechanisms responsible for adverse effects are discussed.

Caudal epidural block for analgesia following herniorrhaphy with laparoscopy in children

This study prospectively evaluated the efficacy of caudal epidural block in providing analgesia following inguinal herniorrhaphy and laparoscopy. Laparoscopy was used only to inspect the contralateral side to determine if a second hernia was present. No surgical manipulation was performed through the telescope. Following mask induction with halothane in nitrous oxide and oxygen, a caudal epidural block was performed with 1.2 mL/kg of 0.25% bupivacaine. Pain scores were obtained at four points during the in-hospital postoperative course, and the need for supplemental analgesic agents was assessed. A total of 45 patients were studied. Caudal epidural block could not be performed in 1 patient, and this patient was excluded from further consideration. There were 34 boys and 10 girls, ranging in age from 2 to 84 months (mean +/- SD 37.4 +/- 18.2 months) and weighing from 3.4 to 34 kg (mean +/- SD 14.2 +/- 5.8 kg). Thirty-six of 44 patients (82%) did not require supplemental analgesic agents during their in-hospital postoperative course and had pain scores of 2 or less at all four evaluation points. Six of 8 patients required a single dose of intravenous fentanyl (0.5 microgram/kg) to maintain scores of 2 or less. No significant complications related to caudal epidural block were noted in any patient. Caudal epidural block provides effective analgesia following inguinal herniorrhaphy and laparoscopy in children.

Anesthetic implications of the child with homocystinuria

We present a 7 1/2-year-old girl with type I homocystinuria who required anesthetic care during repair of bilateral ectopia lentis. Homocystinuria is an autosomal recessive disorder and represents the second most common error of amino acid metabolism. Defective function of the enzyme cystathionine synthetase results in elevated serum levels of methionine and homocysteine. Physiologic disturbances include an increased risk of thromboembolic events and hypoglycemia. Perioperative measures to prevent thromboembolic events include diet therapy to lower serum methionine and homocysteine levels, adequate preoperative hydration, maintenance of intraoperative cardiac output, and the use of pneumatic stockings to prevent peripheral stagnation of blood. Hypoglycemia is thought to be due to alterations in insulin release associated with high levels of circulating sulfur-containing amino acids such as methionine. Perioperative measures include normalization of serum methionine and administration of exogenous glucose during periods of fasting.

Pain management of the pediatric patient

Recent evidence has documented the deleterious physiologic effects of pain. The treatment of pain in children may be guided by a step-wise approach depending on its severity (Table 2). Mild pain can generally be controlled with a NSAID, such as ibuprofen, whereas moderate pain may require the addition of an orally active narcotic. Several approaches may be taken for the treatment of severe pain, including regional anesthetic techniques or the use of PCA to deliver intravenous narcotics. When such techniques fail, consultation with specialists in the field of pediatric pain management may be helpful.

Methylprednisolone increases sensitivity to beta-adrenergic agonists within 48 hours in Basenji greyhounds

BACKGROUND

Corticosteroids used in combination with bronchodilators are significantly more effective than placebo combined with bronchodilators in the acute treatment of bronchospasm. Because the time course for this effect is not known, and is of importance in the preoperative preparation of patients with reactive airway disease, the authors investigated the time course by which methylprednisolone increased sensitivity to the beta-adrenergic agonist, albuterol, in a dog model with airway hyperresponsiveness.

METHODS

Airway responsiveness to methacholine alone and in the presence of albuterol was determined before treatment with methylprednisolone in nine Basenji greyhounds. Each dog was then treated with methylprednisolone for 1 week. Airway responsiveness to methacholine in combination with albuterol was determined after 24 h, 48 h, and 1 week of methylprednisolone treatment.

RESULTS

Albuterol alone did not alter airway responsiveness to methacholine in Basenji greyhounds before methylprednisolone treatment and after 24 h of methylprednisolone treatment. Methylprednisolone, however, significantly decreased pulmonary responses to methacholine in albuterol-pretreated dogs at 48 h.

CONCLUSIONS

The authors concluded that methylprednisolone increased sensitivity to the beta-adrenergic agonist, albuterol, within 48 h.

Postoperative analgesia following thoracotomy in children: interpleural catheters

The authors retrospectively review their experience in children with the latest addition to the postoperative analgesic armamentarium: interpleural analgesia (IPA). IPA was used in 14 children following thoracotomy. There were 9 boys and 5 girls. Patients varied in age from 2 months to 17 years 4 months (mean +/- SEM = 7.6 +/- 1.6 yr). Catheters were left in place from 10 to 72 hours (mean +/- SEM = 45.1 +/- 4.6 h). Four patients received intermittent bolus doses and 10 patients received a continuous infusion through the interpleural catheters. Adequate analgesia, as judged by both subjective responses (decreased irritability or complaints of pain) and by objective physiologic responses (decreased heart rate, respiratory rate, and systolic blood pressure), was achieved in 13 of 14 patients. Eight of the 14 children required no additional analgesic agents. One child received 2 doses of oral codeine and 4 patients received 2 to 3 doses of intravenous narcotic during IPA. IPA was not effective in one patient who required 6 doses of intravenous meperidine. Patients more than 10 years of age required significantly more (P < 0.05) intravenous narcotic supplementation than patients less than 10 years of age (1.60 +/- 0.50 v 0.14 +/- 0.11 mg meperidine/kg/d). No complications related to placement or subsequent use of IPA were identified in any of the patients. IPA provides effective postoperative analgesia following thoracotomy in children.

Continuous regional anaesthesia in infants

Physiological immaturity of the respiratory musculature and central respiratory control centres leads to an increased risk of apnoea and respiratory complications following general anaesthesia in neonates. Regional anaesthetic techniques may obviate the need for general anaesthesia and lessen the risks of perioperative morbidity. Although these techniques have been described in infants, previous reports have dealt with single-shot techniques for brief surgical procedures (< 60 min). Experience with prolonged operative cases using regional anaesthesia via indwelling catheters in infants is limited. We present our experience with four infants in whom either caudal epidural or spinal anaesthesia was administered via indwelling catheters for operative procedures that lasted 90 to 180 min. We believe this technique is an alternative to general anaesthesia in these patients.

Disposition and respiratory effects of intrathecal morphine in children

BACKGROUND

The extent and duration of respiratory depression after opioid administration are poorly defined in infants and children.

METHODS

The disposition and respiratory effects of intrathecal morphine were studied in ten patients (ages 4 months-15 yr) after repair of craniofacial defects. Morphine, 0.02 mg/kg, was administered intrathecally before the end of surgery. Postoperatively, we determined the minute ventilation (VE) in response to increasing partial pressure of end-tidal carbon dioxide (PETCO2) during carbon dioxide rebreathing. The slope (VE/PETCO2) and intercept (VE at PETCO2 60 mmHg, VE 60) of the carbon dioxide response curve were calculated at 6, 12, and 18 h after morphine administration. Cerebrospinal fluid (CSF) and blood were analyzed for morphine concentration by radioimmunoassay.

RESULTS

Mean VE/PETCO2 decreased from a preoperative value of 35.1 +/- 3.7 to 16.3 +/- 2.8 ml.kg-1 x min-1 x mmHg-1 at 6 h after morphine, and remained depressed to 23.4 +/- 2.9 and 23.5 +/- 3.3 ml.kg-1 x min-1 x mmHg-1 at 12 h and 18 h, respectively, compared to preoperatively). The infants' (n = 3) VE/PETCO2 at 6 h were 21, 4, and 27 ml.kg-1 x min-1 x mmHg-1. Mean VE 60 decreased from 874 +/- 125 to 276 +/- 32 ml x kg-1 x min-1 at 6 h, but then recovered at 12 and 18 h to 491 +/- 68 and 567 +/- 82 ml.kg-1 x min-1, respectively. The infants' VE 60 at 6 h were 350, 142, and 245 ml.kg-1 x min-1. Mean CSF morphine concentration was 2,860 +/- 540 ng/ml at 6 h, and decreased to 640 +/- 220 and 220 +/- 150 ng/ml at 12 and 18 h, respectively.

CONCLUSIONS

Intrathecal morphine, 0.02 mg/kg, depressed the ventilatory response to carbon dioxide for up to 18 h concomitant with increased CSF morphine concentrations. Infants (4-12 months of age) did not exhibit greater ventilatory depression than did children (2-15 yr of age).

Thoracic epidural anaesthesia in infants and children

When compared with conventional analgesic techniques, epidural anaesthesia not only provides improved analgesia, but also has several beneficial effects on the postoperative respiratory, cardiovascular, and metabolic status of the patient. Although the efficacy and safety of caudal and lumbar epidural anaesthesia in children has been demonstrated, there is little information concerning the use of thoracic epidural anaesthesia. The purpose of our review was to evaluate the safety of thoracic epidural anaesthesia in infants and children. We retrospectively reviewed our three-year experience with thoracic epidural anaesthesia for postoperative analgesia in children. Epidural catheters were placed at the thoracic level without difficulty in 63 children ranging in age from three months to 18 yr and in weight from 3.2 to 78 kg. Postoperative analgesia was provided by the continuous infusion of a bupivacaine/fentanyl mixture, supplemented with intermittent epidural fentanyl by bolus as needed. Epidural catheters were successfully placed in all patients. No inadvertent dural punctures were noted. No episodes of respiratory depression related to epidural analgesia occurred. Minor adverse effects including pruritus occurred in six patients, three of whom required pharmacological intervention with diphenhydramine. Our review suggests that this is a safe and effective method of postoperative analgesia following thoracic surgery in children.

Anesthetic considerations for endoscopic procedures in children

The use of laparoscopic and thoracoscopic procedures in children continues to increase. Thus, anesthesiologists are faced with an increasing number of children for whom anesthetic care is required during these procedures. Significant physiological alterations may occur that are related to patient positioning and the insufflation of air or CO2 into body cavities. Although exceedingly rare, air embolism also may occur during such procedures. An understanding of the anticipated procedure combined with knowledge of its effects on cardiorespiratory function will assist in planning the anesthetic care. This article deals with the specific anesthetic implications of and the cardiorespiratory alterations induced by endoscopic procedures in children.

Cardiorespiratory responses to epidural analgesia in the awake child: a retrospective review of postoperative patients

The authors retrospectively evaluated the cardiorespiratory effects of epidural administration of bupivacaine in 17 awake children during the immediate postoperative period. Responses to dosing were assessed by comparing heart rate, blood pressure, and respiratory rate before and after administration. Additionally, hourly heart rates were compared between those patients receiving intermittent bolus doses and those receiving a continuous infusion. The patients included 11 boys and 6 girls, ranging in age from 4 months to 12 1/2 years and in weight from 7.4 to 48 kg. All catheters were placed after the induction of general anesthesia. Surgical procedures included exploratory laparotomy (9 patients), bladder reconstruction (4 patients), wound debridement and skin grafting (2 patients), amputation (1 patient), and Nissen fundoplication (1 patient). A total of 37 bolus doses of 0.25% bupivacaine were administered to 7 patients. A significant (P < .001) decrease in heart rate (187 +/- 2 to 137 +/- 1 beats/min), respiratory rate (42 +/- 2 to 25 +/- 1 breaths/min), and systolic blood pressure (125 +/- 3 to 86 +/- 1 mm Hg) was noted after administration. When postdosing cardiorespiratory parameters were compared with preoperative values obtained the day before surgery during the preoperative anesthesia evaluation, there was no significant difference in heart rate (131 +/- 14 versus 137 +/- 13 beats/min), respiratory rate (21 +/- 7 versus 25 +/- 1.0 breaths/min), and systolic blood pressure (93 +/- 9 versus 86 +/- 2 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of midazolam prepared for oral administration

Midazolam is used frequently as an oral premedication in children. To make it more palatable, it is often mixed in various syrups and solutions. No previous studies have documented the stability of midazolam when mixed in these solutions. Using high-pressure liquid chromatography, we assayed midazolam concentrations over time when mixed at two different concentrations (2.5 mg/mL and 3.0 mg/mL) in a sucrose-based syrup (Simple Syrup, NF). Each assay was done in triplicate on three different days (days 1, 14, and 38). Solution A concentrations (2.5 mg/mL) were 2.28 mg/mL on day 1, mg/mL) were 2.82 mg/mL on day 1, 2.91 mg/mL on day 14, and 2.24 mg/mL on day 38. Our results confirm the stability of midazolam for up to 14 days when mixed for oral administration.

Anaesthetic implications of cystinosis

The author presents and discusses the anaesthetic care of a 12-yr-old boy with cystinosis. Cystinosis is a recessively inherited disorder of amino acid metabolism resulting in the abnormal intracellular accumulation of cystine. Anaesthetic care may be affected by variable end-organ involvement, most notably progressive renal deterioration beginning with the development of Fanconi syndrome and progressing to overt renal failure during the first decade of life. Additional organ system involvement may lead to cirrhosis with portal hypertension, diabetes mellitus, and hypothyroidism. Identification of the extent of end-organ involvement during the preoperative evaluation will help in the provision of safe anaesthetic care for such patients.

Neonatal regional anesthesia: alternative to general anesthesia for urologic surgery

The physiologic immaturity of respiratory musculature and central respiratory control centers leads to an increased risk of apnea and respiratory complications following general anesthesia in the neonate. Regional anesthetic techniques such as spinal and caudal epidural anesthesia may obviate the need for general anesthesia and lessen the risks of perioperative morbidity. Although these techniques have been previously described in infants, the majority of reports focus on regional anesthesia during herniorrhaphy in the former, preterm infant. There is relatively little or no information concerning regional anesthesia during urologic surgery in infants, especially during the actual neonatal period (0 to 28 days). We report on three neonates (2.17 to 3.8 kg) who required anesthetic care during the neonatal period for various urologic procedures including cystoscopy, incision of a ureterocele, and vesicostomy placement. Either caudal or spinal anesthesia was successfully used in the awake infant without the need for supplemental anesthetic agents (intravenous or inhalational). The advantages, risks, and applications of regional anesthesia during urologic surgery in the neonate are reviewed.

Management of minor adverse effects encountered during narcotic administration

Presented are four clinical scenarios of patients receiving narcotics to control pain of various etiologies. In all cases minor adverse effects necessitated intervention so that continued use of these agents was possible. The four cases illustrate common adverse effects, including nausea, vomiting, pruritus, and dysphoria, that may occur during narcotic administration. Management strategies to deal with these and other common non-life-threatening effects of narcotic agents are presented.

Anesthetic considerations in the child with Gaucher disease

We present the case of a 7-month-old girl with Gaucher disease who required anesthetic care during laryngoscopy, bronchoscopy, and central line placement. Gaucher disease is a familial disorder of lipid catabolism with autosomal recessive inheritance. Due to the defective function of the enzyme glucosylceramide beta-glucosidase, glycosphingolipids accumulate, leading to end-organ dysfunction. Three clinical variants of the disease, which differ in age of onset, degree of central nervous system (CNS) involvement, and frequency in the population, have been described. Of concern to the anesthesiologist is the occurrence of significant CNS dysfunction in types II and III, with seizures, gastroesophageal reflux, and chronic aspiration. Bulbar involvement and infiltration of the upper airway with glycolipids may lead to upper airway obstruction. Additionally, hepatosplenomegaly, present in all three variants, may lead to hypersplenism with thrombocytopenia and anemia. Preoperative identification of the associated end-organ dysfunction will allow the safe provision of anesthetic care for these children.

Postoperative outcome following thoracotomy in the pediatric oncology patient with diminished pulmonary function

Surgical resection of pulmonary metastatic disease is often indicated in pediatric malignancies. Although several adult studies document increased postoperative morbidity in adults with diminished pulmonary function, there is little information in the pediatric population or in patients with restrictive lung disease. We reviewed the postoperative course following thoracotomy in patients with diminished pulmonary function (FVC, FEV1, or TLC less than 80% predicted). Thirty-two thoracotomies were performed in 19 patients. The preoperative FVC (% predicted) was 68 +/- 3.6 with a postoperative value of 60 +/- 2.4 (P < 0.01). The preoperative FEV1 was 69 +/- 4.2 with a postoperative value of 60 +/- 3.8 (P < 0.01). Although there was a significant drop in pulmonary function tests (PFTs) following surgery, there was not a significantly greater loss when comparing patients with mild, moderate, and severe disease. When considering postoperative morbidity, there were 3 events (prolonged oxygen requirement, need for postoperative ventilation, or persistent air leak) following 20 surgeries in patients with mild preoperative respiratory dysfunction, 5 events (including one death) in the 7 patients with moderate dysfunction, and 3 events following 5 surgeries in patients with severe dysfunction. There was no correlation with a decrease in any specific PFT and the occurrence of postoperative morbidity. Our limited review suggests that aggressive surgical treatment of metastatic pulmonary disease is tolerated even in patients with severe decreases in pulmonary function.

Indications and application of epidural anesthesia in a pediatric population outside the perioperative period

The techniques of spinal and epidural anesthesia have been key components of anesthetic care for the past 100 years. Although commonly used in the operating room, their use in children outside the perioperative period has been limited. The author presents his experience with the use of epidural anesthesia to provide analgesia in five children when parenteral narcotics were ineffective in treating pain associated with burns, sickle cell crisis, trauma, and malignancies. Additionally, the principles and adverse effects of epidural anesthesia are discussed.

Ondansetron to prevent emesis following N-acetylcysteine for acetaminophen intoxication

We present a 17-year-old girl who developed persistent vomiting following acetaminophen overdose. Because of the amount of drug ingested (300 mg/kg acetaminophen) and the four-hour postingestion level (256 micrograms/ml), administration of N-acetylcysteine (NAC) was indicated. Emesis occurred immediately following the first three doses of NAC despite administering the drug by continuous nasogastric drip over one hour. Prior to the next attempt, ondansetron (0.15 mg/kg) was administered intravenously as an antiemetic. Thirty minutes following ondansetron, NAC was tolerated without further emesis. Although several antiemetics may have prevented further emesis, we chose ondansetron since, as a serotonin antagonist, it does not cause extrapyramidal side effects or sedation. In patients with potentially toxic drug ingestions, these side effects may be confused with or mask the adverse effects of the ingested drug, thereby interfering with the ongoing evaluation of the patient. Although not previously administered for this indication, ondansetron has several advantages over other antiemetic agents in the setting of an acute drug ingestion.

Anesthetic considerations of an infant with Beckwith-Wiedemann syndrome

The case of a 3-day-old infant with Beckwith-Wiedemann syndrome who required anesthetic care during closure of an abdominal wall defect is presented. Beckwith-Wiedemann syndrome comprises a constellation of clinical features, including macroglossia, macrosomia, omphalocele, visceromegaly, mild microcephaly, facial nevus flammeus, horizontal earlobe creases, and renal medullary dysplasia. Due to the high rate of omphalocele in this syndrome, anesthetic care is frequently required during the neonatal period. Many of these infants (greater than 50%) are born prematurely. Therefore, their anesthetic care may be further complicated by associated diseases of prematurity, such as hyaline membrane disease. Additional anesthetic implications of this syndrome relate to the occurrence and management of hypoglycemia and polycythemia. Careful intraoperative management of glucose homeostasis is particularly important, since eventual neurologic outcome and intelligence will be normal provided prolonged neonatal hypoglycemia is avoided. Preoperative evaluation of the cardiac and genitourinary system, including echocardiography and renal ultrasound, are recommended because of the frequent occurrence of associated anomalies with omphalocele.

Regional anesthesia in the preterm neonate

The physiologic immaturity of respiratory musculature and central respiratory control centers leads to an increased risk of apnea and respiratory complications following general anesthesia in the neonate. Regional anesthetic techniques, such as spinal and caudal epidural anesthesia, may obviate the need for general anesthesia and lessen the risks of perioperative morbidity. Although these techniques have been previously described in infants, most reports focus on regional anesthesia in the former preterm infant outside the actual neonatal period. There is relatively little or no information concerning regional anesthesia in neonates during the first week of life. We present four neonates (weight, 1.07 to 2.8 kg; gestational age, 27 to 35 weeks) who required anesthetic care during the first week of life for various surgical procedures, including vesicostomy placement, gastroschisis closure, and debridement of a lower-extremity wound. Either caudal epidural or spinal anesthesia was successfully used in the four neonates. Regional anesthesia was used as the sole technique without supplementation with intravenous or inhalational agents in three of the four neonates. The advantages, risks, and applications of regional anesthesia in the neonate are discussed.

Oral ketamine premedication to alleviate the distress of invasive procedures in pediatric oncology patients

This study prospectively evaluated the efficacy of oral ketamine in alleviating procedure-related distress in pediatric oncology patients. Ketamine (10 mg/kg) was administered orally to 35 children and adolescents, ranging in age from 14 months to 17 years (mean = 6.5 years). Procedure-related distress was evaluated by using parent/clinician ratings and the Observational Scale of Behavioral Distress (OSBD-R). Eighty-seven percent of children were sedated within 45 minutes. Clinician and parent ratings were similar, with 77% rating procedural distress as low (0 to 3). The OSBD-R scores were low throughout all phases of the study. Although this study was neither randomized nor placebo-controlled, statistical comparison of the OSBD-R scores of the patients who received oral ketamine with those of historical controls (from a study previously performed at the same institution but using intravenous midazolam) showed significantly less distress (P < .001) during the procedure in children who received oral ketamine. Additionally, OSBD-R scores of the patients who received oral ketamine were significantly lower (P < .001) during all phases than those of the saline placebo group in the other study. No cardiorespiratory side effects related to ketamine were noted. The majority of patients showed recovery from sedation within 2 hours following the procedure. In conclusion, oral ketamine effectively alleviated procedure-related distress in pediatric oncology patients.

Anaesthetic considerations in the child with Menkes' syndrome

The author presents and discusses the anaesthetic implications of a four-month-old infant with Menkes' syndrome who required tracheostomy. Menkes' syndrome is an X-linked recessive disorder of copper absorption and metabolism. Defective processing of copper results in abnormalities of several enzyme systems leading to severe dysfunction of multiple organ systems. Due to the progressive nature of this disorder and its severe effects on several different organ systems, most importantly the central nervous system, these children frequently require anaesthetic care during imaging procedures such as MRI or during various surgical operations. The high prevalence of seizure disorders, gastroesophageal reflux with the risk of aspiration, and airway complications related to poor pharyngeal muscle control are of concern to the anaesthetist. In addition, defective collagen formation, similar to that seen in Ehlers-Danlos syndrome, may be present. Identification of these associated conditions during the preoperative examination will guide the selection of appropriate, safe anaesthetic care for these children.

Continuous epidural anesthesia for postoperative analgesia in the pediatric oncology patient

When compared with conventional techniques, epidural anesthesia not only provides improved analgesia, but also has several beneficial effects on the postoperative respiratory, cardiovascular, and metabolic status of the patient. Although the efficacy of this technique in children has been demonstrated, extensive experience in the pediatric oncology patient has not been previously reported. We retrospectively reviewed our 2-year experience with epidural analgesia and discuss the techniques involved in implementing this service for the pediatric oncology patient. An epidural catheter was successfully placed in 58 of 60 patients (97%) who ranged in age from 4 months to 19 years and in weight from 4.1 to 68 kg. Postoperative analgesia was provided by a continuous infusion of a bupivacaine/fentanyl mixture, supplemented with intermittent epidural fentanyl by bolus dose as needed. No complications related to epidural catheters were noted. Our review supports the efficacy of this technique for providing postoperative analgesia after various major surgical procedures in the pediatric oncology patient.

Pediatric analgesia with epidural fentanyl citrate administered by nursing staff

Even though epidural analgesia is effective and has advantages over conventional postoperative analgesia, it is also labor intensive, requiring 24-hour supervision by an anesthesiologist. In an effort to decrease the manpower requirements, some hospitals allow the nursing staff to administer epidural narcotics to adult patients. In children, however, this practice has been limited. We retrospectively reviewed our experience over 12 months with this procedure. Epidural catheters (caudal, lumbar, or thoracic) were placed in 43 pediatric patients for acute and chronic pain management. All patients received a continuous epidural infusion of bupivacaine hydrochloride with fentanyl citrate. Eleven (26%) of the 43 patients required supplemental analgesia and were given 45 doses of epidural fentanyl. Adequate analgesia was achieved in all patients. No intravascular or intrathecal injections were noted, nor did any inadvertent epidural injections of medications occur. No patient had respiratory depression (respiratory rate less than 10% for age). We believe epidural administration of fentanyl by a carefully educated nursing staff is safe and effective in children.

Anaesthetic considerations for the child with leukodystrophy

The author presents a four-year-old boy with Pelizaeus-Merzbacher disease who required anaesthesia during placement of PE (pressure equalization) tubes and a permanent silastic intravascular device (Broviac catheter). Pelizaeus-Merzbacher is one of a group of progressive, degenerative disorders of the cerebral white matter known as the leukodystrophies. They include metachromatic leukodystrophy, adrenoleukodystrophy, Krabbe's disease, Canavan's disease, Alexander's disease and Pelizaeus-Merzbacher disease. Due to the progressive nature of the disorders and their devastating effects on the central nervous system, these children frequently require anaesthesia during imaging procedures such as MRI or during various surgical procedures. Of concern to the anaesthetist is the high prevalence of seizure disorders, gastroesophageal reflux with the risk of aspiration, and airway complications related to poor pharyngeal muscle control and copious oral secretions. In addition, adrenal involvement and hypofunction may be seen in patients with adrenoleukodystrophy. Identification of these associated conditions during the preoperative examination will allow safe anaesthesia for these children.

Patient-controlled analgesia with fentanyl in children

We have found that fentanyl delivered by PCA provides an effective alternative when adverse effects occur with other more frequently used narcotics. Although anecdotal experience exists concerning the use of fentanyl PCA in adults, dosing guidelines in children must depend on consideration of the current narcotic regimen and the use of equipotent doses of fentanyl. Our initial experience suggests that this is a safe and reliable technique; however, until prospective studies further delineate dosing guidelines, close observation (continuous pulse oximetry and hourly checks of respiratory rate) of these patients is recommended. With such caveats, fentanyl PCA appears to provide an acceptable alternative to "more conventional" narcotics.

Methylprednisolone restores sensitivity to beta-adrenergic agonists in Basenji-Greyhound dogs

This study investigated the effect of chronic methylprednisolone treatment on the ability of albuterol and aminophylline to inhibit methacholine-induced airway constriction in Basenji-Greyhound (BG) dogs in vivo. Pulmonary responsiveness to methacholine was measured in five untreated BG dogs and in the same dogs pretreated with albuterol or aminophylline (which has been shown in this model to release endogenous catecholamines). Each dog was studied before, during, and after daily subcutaneous methylprednisolone for 6 wk. Changes in pulmonary resistance and dynamic compliance with methacholine aerosol challenge were measured. Neither baseline pulmonary function nor pulmonary responsiveness to aerosolized methacholine was significantly altered by albuterol, aminophylline, or chronic methylprednisolone administration alone. However, pretreatment with albuterol or aminophylline significantly attenuated airway responses to methacholine in BG dogs chronically receiving methylprednisolone. Because the reduced sensitivity to albuterol and aminophylline was restored by chronic methylprednisolone treatment, we conclude that at least part of the beneficial effects of corticosteroids on airways in BG dogs is through modulation of beta-adrenergic function.

Removal of phenytoin by plasmapheresis in a patient with thrombotic thrombocytopenia purpura

Phenytoin removal by plasmapheresis was evaluated in a 17-year-old girl with thrombotic thrombocytopenia purpura. Free and total phenytoin concentrations were measured in the patient's serum and in the plasma removed by plasmapheresis. Plasmapheresis was performed on three separate days with the removal of 4.7%, 3.3%, and 2.7% of total body stores. Free phenytoin concentration was similar in both the plasma removed by plasmapheresis and the patient's serum. Plasmapheresis did not significantly alter the serum concentration of phenytoin; dosage adjustments of phenytoin are therefore unnecessary.

Analgesia after thoracotomy in children: a comparison of interpleural, epidural, and intravenous analgesia

The cohort for this study included 39 patients, between the ages of 8 and 20 years, who had had thoracotomy. Postoperative analgesia was provided by one of three techniques: intravenous narcotics (20 patients), thoracic epidural catheter (10 patients), or interpleural analgesia (IPA) (nine patients). Both IPA and epidural analgesia were administered according to a specific protocol. The efficacy of the three methods was evaluated using two indicators: the total intravenous narcotic requirements for the initial 72 hours and the number of times a dose of intravenous narcotic or supplemental epidural fentanyl was administered to each patient. Patients in the IPA group required significantly less intravenous narcotics (P less than .05) during the first three postoperative days (2.2 +/- 0.4, 1.9 +/- 0.6, and 1.4 +/- 0.5 mg of meperidine/kg/day) than patients in the intravenous narcotic group (8.1 +/- 1.2, 7.2 +/- 0.9, and 5.6 +/- 1.2 mg of meperidine/kg/day). When comparing epidural analgesia and IPA, the number of interventions in the patients receiving epidural analgesia was significantly less (P less than .05) than in the group receiving IPA. Four of 10 patients in the epidural group and two of nine in the IPA group required no interventions during the initial 72-hour postoperative course. In the epidural analgesia group, there were 19 days (of a total of 30 days) during which patients required no interventions. This percentage was significantly greater (P less than .05) than that of the IPA group, in which there were 9 days (of a total of 27 days), during which no interventions were required.

Continuous intrathecal fentanyl infusion for postoperative analgesia

Following inadvertent dural puncture during epidural catheter placement, a 20 gauge polyethylene catheter was placed in the intrathecal space, and continuous spinal anesthesia with hyperbaric bupivacaine was administered intraoperatively to supplement general anesthesia. Following surgery, a continuous intrathecal fentanyl infusion (0.2 mcg/kg/hr) was administered to provide postoperative analgesia. The child was awake and comfortable throughout this time and required no supplemental analgesic agents. Although epidural catheters are still our preferred method of analgesia, intrathecal fentanyl infusion is one alternative when inadvertent dural puncture occurs.

Granulocyte transfusions--a review for the intensive care physician

In order to achieve the maximum therapeutic benefit in the treatment of malignancies, doses of chemotherapeutic agents are pushed to the point of severe marrow toxicity. This aggressive therapy can lead to iatrogenic complications including haemorrhage and sepsis due to the depletion of platelets and granulocytes. Prior to the advent of platelet transfusions, haemorrhage was the leading cause of death in these patients. Advances in blood banking and the availability of platelet transfusions have markedly decreased the incidence of fatal haemorrhage. As a result, infection has become the leading cause of death in patients with marrow failure. Although the risk of infection in patients with neutropenia has been well documented, the role of granulocyte transfusions in the treatment and prevention of these infections remains controversial. This paper will attempt to review the currently available literature regarding granulocyte procurement techniques and the efficacy of granulocyte transfusions.

Postsepsis bradycardia in children with leukemia

OBJECTIVE

We observed sinus bradycardia in a small number of children with hematologic malignancies who were recovering from sepsis. Our objective was to define this symptom complex and attempt to delineate its etiology.

DESIGN

Retrospective chart review.

SETTING

A pediatric ICU in a children's oncology hospital.

PATIENTS

Children admitted to the ICU over a 24-month period who developed persistent bradycardia (heart rate less than 5% for age for greater than 1 hr) after an episode of sepsis.

MEASUREMENTS AND MAIN RESULTS

Seven children developed postsepsis bradycardia. Six patients had a primary diagnosis of acute myelogenous leukemia and one patient had acute lymphocytic leukemia. All patients had positive blood cultures (Streptococcus mitis, n = 4; Escherichia coli, n = 2; and Klebsiella pneumoniae, n = 1). All seven children were clinically recovering from sepsis when the bradycardia developed. Neither hypotension nor other symptom was associated with the bradycardia. No therapy was given for the bradycardia. Echocardiograms and ECGs were normal in all patients, except for the presence of bradycardia. Bradycardia persisted for 24 to 72 hrs. After that time, heart rates slowly increased to the normal range for age.

CONCLUSIONS

We speculate that this syndrome may result from alterations in beta-adrenergic receptor function or an unidentified humoral factor produced by the invading organism or as part of the host's response to sepsis. Prior drug therapy or the underlying illness may predispose to this condition, since all the patients had acute leukemia. As the bradycardia was clinically insignificant, invasive therapeutic or diagnostic strategies were not indicated.

Methylprednisolone prevents propranolol-induced airway hyperreactivity in the Basenji-greyhound dog

To determine if corticosteroids would prevent beta-adrenergic-antagonist-induced increases in airway reactivity, we evaluated the ability of chronic methylprednisolone administration to prevent propranolol-induced airway hypereactivity to methacholine aerosol in the basenji-greyhound (BG) dog model of asthma. Initial studies included the measurement of lung resistance (RL) and dynamic compliance (Cdyn) with and without propranolol pretreatment in 5 BG and 5 mongrel dogs. A single dose of propranolol (2 mg/kg) did not significantly alter airway reactivity in the mongrels. The dose of methacholine needed to increase RL by 200% (ED200RL) was 0.20 +/- 0.05 mg/ml (mean +/- standard error of the mean [SEM]) in untreated and 0.18 +/- 0.04 mg/ml in propranolol-treated mongrels. In contrast, propranol significantly increased methacholine-reactivity in the BGs. The ED200RL for methacholine was 0.17 +/- 0.03 mg/ml in untreated and 0.05 +/- 0.02 mg/ml (P less than 0.05) in propranolol-treated BG dogs. Following the initial studies, the 5 BG dogs were given methylprednisolone (2 mg.kg-1.day-1) for 4 weeks, after which time propranolol no longer increased methylacholine reactivity in the BGs. The ED200RL was 0.16 +/- 0.03 mg/ml after 4 weeks of methylprednisolone and 0.22 +/- 0.06 mg/ml after propranolol administration in the BGs given 4 weeks of methylprednisolone treatment. The attenuation of propranolol-induced bronchoconstriction by corticosteroids may be a clinically useful intervention in asthmatic patients receiving beta-adrenergic antagonists in the perioperative period. However, further studies are needed to define the effective dose and duration of corticosteroid therapy that is needed.

Vincristine-induced recurrent laryngeal nerve paralysis in children

Stridor developed in 2 children during vincristine therapy for malignancies. Indirect laryngoscopy revealed left vocal cord paralyses in both patients. One child had generalized neurotoxicity from vincristine including hypotonia, decreased gastrointestinal motility, and painful paresthesias while laryngeal nerve paralysis was the only neurotoxic manifestation in the other patient. Stridor resolved in both patients after discontinuing or decreasing the dose of vincristine. Visualization of the airway not only confirms the diagnosis, but also rules out treatable causes of stridor in the febrile, immunocompromised patient.

Percutaneous lumbar intrathecal catheter for the administration of chemotherapy

We present a patient with Burkitt's lymphoma in whom the initial diagnostic lumbar puncture was difficult due to a recent lumbar laminectomy and residual spinal cord tumor. According to our current protocol, he was to receive intrathecal chemotherapy for three consecutive days. To avoid the need for repeated attempts at lumbar puncture and to ensure the proper instillation of therapy, a percutaneous IT catheter was placed for 48 hours and the three doses of IT chemotherapy were administered through this catheter. Due to the importance of IT chemotherapy, options must be available to deliver these medications when technical or anatomic abnormalities exist. One such option is the short term placement of a percutaneous IT catheter.