Clinical uses and controversies of neuromuscular blocking agents in infants and children

Spontaneous recovery from neuromuscular block after a single dose of a muscle relaxant in pediatric patients: A systematic review using a network meta-analytic and meta-regression approach

BACKGROUND

Age-related differences in the pharmacokinetics and pharmacodynamics of neuromuscular blocking agents (NMBAs) and the short duration of many surgical procedures put pediatric patients at risk of postoperative residual curarization (PORC). To date, the duration of neuromuscular blocking agent effect in children has not been analyzed in a quantitative review. The current meta-analysis aimed to compare spontaneous recovery following administration of various types and doses of neuromuscular blocking agents and to quantify the effect of prognostic variables associated with the recovery time in pediatric patients.

METHOD

We searched for randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that compared the time to 25% T1 (t25), from 25% to 75% T1 (RI25-75), and to ≥90% train-of-four (tTOF90) neuromuscular recovery between common neuromuscular blocking agent treatments administered as a single bolus to healthy pediatric participants. We compared spontaneous t25, RI25-75, and tTOF90 between (1) neuromuscular blocking agent treatments and (2) age groups receiving a given neuromuscular blocking agent intervention and anesthesia technique. Bayesian random-effects network and pairwise meta-analyses along with meta-regression were used to evaluate the results.

RESULTS

We used data from 71 randomized controlled trials/controlled clinical trials including 4319 participants. Network meta-analysis allowed for the juxtaposition and ranking of spontaneous t25, RI25-75, and tTOF90 following common neuromuscular blocking agent interventions. For all neuromuscular blocking agents a log-linear relationship between dose and duration of action was found. With the neuromuscular blocking agent treatments studied, the average tTOF90 (mean[CrI95]) in children (>2-11 y) was 41.96 [14.35, 69.50] and 17.06 [5.99, 28.30] min shorter than in neonates (<28 d) and infants (28 d-12 M), respectively. We found a negative log-linear correlation between age and duration of neuromuscular blocking agent effect. The difference in the tTOF90 (mean[CrI95]) between children and other age groups increased by 21.66 [8.82, 34.53] min with the use of aminosteroid neuromuscular blocking agents and by 24.73 [7.92, 41.43] min with the addition of sevoflurane/isoflurane for anesthesia maintenance.

CONCLUSIONS

The times to neuromuscular recovery are highly variable. These can decrease significantly with age and are prolonged when volatile anesthetics are administered. This variability, combined with the short duration of many pediatric surgical procedures, makes quantitative neuromuscular monitoring mandatory even after a single dose of neuromuscular blocking agent.

Neurophysiological Assessment of Prolonged Recovery From Neuromuscular Blockade in the Neonatal Intensive Care Unit

Objective: To evaluate recovery from neuromuscular blockade in infants using Train-of-Four nerve stimulation. Study Design: Ulnar nerve stimulation was used to evoke thumb twitch and reported as Train-of-Four ratio. Thumb twitch was also recorded visually in real-time. Primary outcome was time to near recovery of muscle function (Train-of-Four ratio >70%). Secondary analyses were time to greater degrees of recovery (Train-of-Four ratio >80, 90%), sensitivity of accelerometry vs. visual thumb-twitch and clinical variates to assess safety. Results: Patients were enrolled following rocuronium-boluses (n = 10) and vecuronium-infusions (n = 9). Median recovery time to Train-of-Four ratio >70% was 14 h following rocuronium-bolus dosing and 34 h following cessation of continuous vecuronium infusion. Median stimulus threshold for accelerometry was 27.5 mA and visual observation was 20 mA. There were no safety concerns. Conclusion(s): Neuromuscular monitoring using Train-of-Four nerve stimulation is feasible in infants. Some infants exhibited prolonged recovery from neuromuscular-blockade. These pilot data may facilitate future standardized pediatric protocols on neuromuscular monitoring for safer dosing.

Premedication for Endotracheal Intubation in the Neonate

Endotracheal intubation, a common procedure in neonatal intensive care, results in distress and disturbs physiologic homeostasis in the newborn. Analgesics, sedatives, vagolytics, and/or muscle relaxants have the potential to blunt these adverse effects, reduce the duration of the procedure, and minimize the number of attempts necessary to intubate the neonate. The medical care team must understand efficacy, safety, and pharmacokinetic data for individual medications to select the optimal cocktail for each clinical situation. Although many units utilize morphine for analgesia, remifentanil has a superior pharmacokinetic profile and efficacy data. Because of hypotensive effects in preterm neonates, sedation with midazolam should be restricted to near-term and term neonates. A vagolytic, generally atropine, blunts bradycardia induced by vagal stimulation. A muscle relaxant improves procedural success when utilized by experienced practitioners; succinylcholine has an optimal pharmacokinetic profile, but potentially concerning adverse effects; rocuronium may be the agent of choice based on more robust safety data despite a relatively prolonged duration of action. In the absence of an absolute contraindication, neonates should receive analgesia with consideration of sedation, a vagolytic, and a muscle relaxant before endotracheal intubation. Neonatal units must develop protocols for premedication and optimize logistics to ensure safe and timely administration of appropriate agents.

The effect of prior tetanic stimulation on train-of-four monitoring in paediatric patients: A randomised open-label controlled trial

BACKGROUND

In clinical research, neuromuscular monitoring must present a stable response for a period of 2 to 5 min before administration of a neuromuscular blocking agent. The time required to reach this stable response may be shortened by applying a 5-s tetanic stimulus.

OBJECTIVES

The aim of this study was to test whether tetanic stimulation interferes with onset and recovery times after a single dose of rocuronium 0.6 mg kg followed by spontaneous recovery.

DESIGN

A randomised, open-label, controlled trial.

SETTING

A single-centre trial, study period from January 2014 to July 2015.

PATIENTS

Fifty children aged 2 to 11 years scheduled for elective paediatric surgery.

INTERVENTION

Patients were randomly allocated to receive either tetanic stimulation (group T) or not (group C) before calibration of the neuromuscular monitor.

MAIN OUTCOME MEASURES

Onset and recovery times. Initial and final T1 height, time to obtain initial T1 height stability and monitor settings were also analysed.

RESULTS

There was no significant difference in mean onset time [(C: 57.5 (± 16.9) vs. T: 58.3 (± 31.2) s; P = 0.917]. Mean times to normalised train-of-four (TOF) ratios of 0.7, 0.8 and 0.9 were significantly shorter in the tetanic stimulation group [C: 40.1 (±7.9) vs. T: 34.8 (±10) min; P = 0.047, C: 43.8 (±9.4) vs. T: 37.4 (±11) min; P = 0.045 and C: 49.9 (±12.2) vs. T: 41.7 (±13.1) min; P = 0.026, respectively]. The mean time required for T1 height stabilisation was similar in the two groups [C: 195.0 (± 203.0) vs. T: 116.0 (± 81.6) s; P = 0.093], but the initial and final T1 height values were significantly lower in the tetanic stimulation group (C: 98.0 vs. T: 82.7%; P < 0.001 and C: 95.3 vs. T: 69.3%; P < 0.001, respectively).

CONCLUSION

Tetanic stimulation shortened the mean times to normalised TOF ratios of 0.7, 0.8 and 0.9, but there was no difference in the mean onset time or the mean time required for T1 height stabilisation after a single dose of rocuronium 0.6 mg kg followed by spontaneous recovery in children aged 2 to 11 years.

TRIAL REGISTRATION

Clinicaltrials.gov. identifier: NCT02498678.

Short-term effects of neuromuscular blockade on global and regional lung mechanics, oxygenation and ventilation in pediatric acute hypoxemic respiratory failure

Background

Neuromuscular blockade (NMB) has been shown to improve outcome in acute respiratory distress syndrome (ARDS) in adults, challenging maintaining spontaneous breathing when there is severe lung injury. We tested in a prospective physiological study the hypothesis that continuous administration of NMB agents in mechanically ventilated children with severe acute hypoxemic respiratory failure (AHRF) improves the oxygenation index without a redistribution of tidal volume V_T toward non-dependent lung zones.

Methods

Oxygenation index, PaO₂/FiO₂ ratio, lung mechanics (plateau pressure, mean airway pressure, respiratory system compliance and resistance), hemodynamics (heart rate, central venous and arterial blood pressures), oxygenation [oxygenation index (OI), PaO₂/FiO₂ and SpO₂/FiO₂], ventilation (physiological dead space-to-V_T ratio) and electrical impedance tomography measured changes in end-expiratory lung volume (EELV), and V_T distribution was measured before and 15 min after the start of continuous infusion of rocuronium 1 mg/kg. Patients were ventilated in a time-cycled, pressure-limited mode with pre-set V_T. All ventilator settings were not changed during the study.

Results

Twenty-two patients were studied (N = 18 met the criteria for pediatric ARDS). Median age (25–75 interquartile range) was 15 (7.8–77.5) weeks. Pulmonary pathology was present in 77.3%. The median lung injury score was 9 (8–10). The overall median CoV and regional lung filling characteristics were not affected by NMB, indicating no ventilation shift toward the non-dependent lung zones. Regional analysis showed a homogeneous time course of lung inflation during inspiration, indicating no tendency to atelectasis after the introduction of NMB. NMB decreased the mean airway pressure (p = 0.039) and OI (p = 0.039) in all patients. There were no significant changes in lung mechanics, hemodynamics and EELV. Subgroup analysis showed that OI decreased (p = 0.01) and PaO₂/FiO₂ increased (p = 0.02) in patients with moderate or severe PARDS.

Conclusions

NMB resulted in an improved oxygenation index in pediatric patients with AHRF. Distribution of V_T and regional lung filling characteristics were not affected.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care: Sedation, Analgesia and Muscle Relaxant

OBJECTIVE

This article reviews pharmacotherapies currently available to manage sedation, analgesia, and neuromuscular blockade for pediatric cardiac critical patients.

DATA SOURCES

The knowledge base of an expert panel of pharmacists, cardiac anesthesiologists, and a cardiac critical care physician involved in the care of pediatric cardiac critical patients was combined with a comprehensive search of the medical literature to generate the data source.

STUDY SELECTION

The panel examined all studies relevant to management of sedation, analgesia, and neuromuscular blockade in pediatric cardiac critical patients.

DATA EXTRACTION

Each member of the panel was assigned a specific subset of the studies relevant to their particular area of expertise (pharmacokinetics, pharmacodynamics, and clinical care) to review and analyze.

DATA SYNTHESIS

The panel members each crafted a comprehensive summary of the literature relevant to their area of expertise. The panel, as a whole, then collaborated to cohesively summarize all the available, relevant literature.

CONCLUSIONS

In the cardiac ICU, management of the cardiac patient requires an individualized sedative and analgesic strategy that maintains hemodynamic stability. Multiple pharmacological therapies exist to achieve these goals and should be selected based on the patient's underlying physiology, hemodynamic vulnerabilities, desired level of sedation and analgesia, and the projected short- or long-term recovery trajectory.

The effects of age, isoflurane and sevoflurane on atracurium in lambs

OBJECTIVE

To determine the effects of age, sevoflurane and isoflurane on atracurium-induced neuromuscular blockade in 3-16 week-old lambs.

STUDY DESIGN

Prospective randomized experimental trial.

ANIMALS

Twenty-six Scottish blackface ewe-lambs were anaesthetized for spinal surgery when either 3-6 (mean age 4.6 weeks; n = 18) or 12-16 weeks (mean age 13.7 weeks; n = 15) of age; seven animals were anaesthetized at both ages.

METHODS

After intramuscular injection of medetomidine (10 μg kg(-1)) anaesthesia was induced in the younger lambs either with isoflurane or sevoflurane in oxygen delivered by mask, and in the older lambs with ketamine (4 mg kg(-1)), and midazolam (0.2 mg kg(-1) ) administered intravenously (IV). In both groups anaesthesia was maintained with fixed end-tidal concentrations of either sevoflurane (2.8%) or isoflurane (1.8%) delivered in oxygen. Before surgery meloxicam (0.6 mg kg(-1)), morphine (0.5 mg kg(-1)) and ketamine (1 mg kg(-1) followed by 10 μg kg(-1) minute(-1) ) were administered IV. The lungs were ventilated mechanically to maintain normocapnia. Neuromuscular block was achieved with a loading dose (LD) of atracurium (0.5 mg kg(-1) IV). The peroneal nerve was stimulated (train-of-four every 12 seconds). Evoked responses in the digital extensor muscles were evaluated by palpation and observation. Maintenance doses (MD) of atracurium (0.17 mg kg(-1) IV) were administered when the first twitch (T1) returned. The onset and duration of LD action (T1 absent) and the duration of MD were recorded. Data were analysed using Student's t test, Mann-Whitney U test, repeated-measures anova, Wilcoxon's matched pairs test or Pearson correlation coefficient as relevant (p < 0.05).

RESULTS

Onset of LD action developed significantly (p < 0.05) more rapidly in isoflurane compared with sevoflurane-anaesthetized lambs (55 ± 18 cf. 80 ± 37 seconds). Duration of action of LDs and MDs was longer (p < 0.05) in lambs aged 12-16 than 3-6 weeks (33 ± 5.4 cf. 25 ± 6.4 and 26 ± 4.2 cf. 18 ± 5.5 minutes) but were independent of the anaesthetic used.

CONCLUSIONS AND CLINICAL RELEVANCE

The effect of atracurium is age-dependent in lambs being prolonged in older animals. The onset of neuromuscular blockade is more rapid in isoflurane compared with sevoflurane-anaesthetized lambs.

Continuous-infusion neuromuscular blocking agents in critically ill neonates and children

Neuromuscular blocking agents (NMBAs) are often administered as a prolonged (> 24 hrs) continuous infusion in infants and children in the intensive care unit for a variety of reasons including facilitation of oxygenation and ventilation. No guidelines on the use of NMBAs in pediatric patients are available yet in the United States; however, pediatric guidelines are available in the United Kingdom. Based on a 2007 U.S. survey, the most commonly used nondepolarizing NMBAs for sustained neuromuscular blockade in critically ill children are pancuronium and vecuronium. Recent national drug shortages involving NMBAs have been reported for atracurium, cisatracurium, pancuronium, rocuronium, and vecuronium. Therefore, to explore alternative options for neuromuscular blockade, we conducted a literature search to identify articles evaluating prolonged use (> 24 hrs) of NMBAs administered by continuous infusion. The search was limited to English-language articles in the MEDLINE (1950-August 2010), EMBASE (1988-August 2010), International Pharmaceutical Abstracts (1970-August 2010), and Cochrane Library (1996-August 2010) databases. Relevant abstracts, reference citations, and manufacturers' product information were also reviewed. A total of 13 reports representing 208 children were included in the analysis. Many of the reports described wide interpatient variability in dosing for the specific NMBAs evaluated. Selection of the most appropriate NMBA should be based on the patient's clinical status, potential adverse effects, and pharmacoeconomics. All patients receiving sustained neuromuscular blockade should be monitored routinely to ensure that dosing is appropriate in order to obtain the desired level of blockade. The goal is to use the lowest dose possible in an effort to limit adverse effects or prolonged blockade.

Acute effects of vecuronium on pulmonary function and hypoxemic episodes in preterm infants

BACKGROUND

Varying effects of pancuronium on neonatal pulmonary mechanics have been documented, including a decrease in pulmonary compliance or no significant change in compliance; but measurements of respiratory mechanics or quantification of episodes of hypoxemia in preterm newborns receiving vecuronium (Norcuron, Bedford Labs, Bedford, OH, USA) have not been reported. The objective of the present study was to quantify the short-term effects of vecuronium on pulmonary mechanics and episodes of hypoxemia in preterm infants receiving mechanical ventilation.

METHODS

A total of 15 preterm infants (birthweight 610-1560 g, gestational age 25-32 weeks, postnatal age 0.2-22 days) was studied. The initial dose of vecuronium used for the study was 0.2 mg/kg i.v. Measurements of respiratory mechanics were obtained 1 h prior to and 1 h after the initial dose of vecuronium at comparable ventilator settings and fractional inspired oxygen concentration (FiO(2)). Dynamic respiratory compliance and respiratory resistance were calculated by two-factor least mean square analysis. Pulse oximeter oxygen saturation (SpO(2)) was measured during both 1 h intervals with the Nellcor N-200 oximeter, a computer, and a software program for quantification of episodes of hypoxemia. Heart rate and blood pressure were also monitored.

RESULTS

There were no significant differences in tidal volume, respiratory compliance, or respiratory resistance when comparing measurements obtained before and after vecuronium administration. However, fewer episodes of hypoxemia (SpO(2) < 85%, P = 0.025; and SpO(2) < 80%, P = 0.04) were observed during muscle relaxation. No significant changes in heart rate or blood pressure were noted.

CONCLUSIONS

The preliminary data indicate: (i) a single dose of vecuronium does not significantly change respiratory compliance or respiratory resistance in preterm infants and (ii) during muscle relaxation fewer episodes of desaturation (hypoxemia) are observed.

Adverse responses: sedation, analgesia and neuromuscular blocking agents in critically ill children

Advanced practice nurses (APNs) prescribe sedation, analgesia, and neuromuscular blocking agents in the management of critically ill children. Although most children are unscathed from the use of the medications, some suffer adverse responses. This article elucidates adverse responses to these medications for the APN, including withdrawal syndrome, muscle weakness, decreased gastric motility, corneal abrasions, and costs associated with these morbidities.

Acute quadriplegic myopathy in a 16-month-old child

We present a case of a 16-month old previously healthy child who was hospitalized because of an acute respiratory insufficiency most likely caused by a viral infection and who then developed a severe acute quadriplegic myopathy (AQM). Initial clinical symptoms were respiratory acidosis, dypnea, intense wheezing, and deterioration of the level of consciousness, which required orotracheal intubation and mechanical ventilation. We administered neuromuscular blocking agents, corticosteroids, and antibiotics. After 9 days the clinical picture improved. An attempt to wean from the ventilator failed. We diagnosed AQM. This paper discusses AQM and its clinical importance.

Sedation and comfort issues in the ventilated infant and child

Intubated infants and children require optimal sedation and comfort measures. Key elements that ensure the provision of quality care for these patients include the use of pain, comfort, and sedation assessment tools; pharmacologic and nonpharmacologic strategies; and the inclusion of the patient and parents as part of the team. This article describes approaches for using sedation and ensuring comfort in these patients. Application of research and the education of team members and the patient and family are crucial aspects of care and are also discussed.

An algorithm for train-of-four monitoring in patients receiving continuous neuromuscular blocking agents

Neuromuscular blocking agents (NMBA) are increasingly being used in the management of critically ill patients. These medications are used to facilitate mechanical ventilation. Strange and colleagues estimated that only 4% of intensive care units utilize train-of-four (TOF) monitoring on a regular basis and that 70% never use this type of monitoring. The ease of use and low cost of the equipment lends itself to the increasingly frequent recommendations for this type of monitoring. Although unwilling to go so far as to establish this as a standard of care, the American College of Critical Care Medicine of the Society of Critical Care Medicine released an executive summary recommending train-of-four monitoring for patients receiving continuous or sustained NMBAs. This protocol and algorithm was developed to facilitate the objective monitoring of patients receiving continuous NMBAs.

Sedation and neuromuscular blockade in paediatric intensive care: a review of current practice in the UK

BACKGROUND

Our aim was to investigate the current practice of sedation and neuromuscular blockade in critically ill children in paediatric intensive care units (PICUs) in the UK.

METHODS

A postal questionnaire was sent to all PICUs in the UK.

RESULTS

The most commonly used sedative agents were midazolam in combination with morphine. Written clinical guidelines for the sedation of critically ill children were available in 45% of units. Sedation is formally assessed in 40% of units. Vecuronium is the most commonly used neuromuscular blocking agent. In the UK, 31% of critically ill children are likely to receive neuromuscular blocking agents. Depth of neuromuscular blockade is routinely assessed in 16% of patients.

CONCLUSIONS

Relatively few units possess clinical guidelines for the sedation of critically ill children, and only a minority formally assess sedation levels. Where neuromuscular blocking agents are administered, sedation is frequently inadequately assessed and the depth of neuromuscular blockade is rarely estimated.

Cisatracurium infusion for neuromuscular blockade in the pediatric intensive care unit: A dose-finding study

OBJECTIVE: To evaluate the safety and efficacy of cisatracurium besylate, a neuromuscular blocking agent in infants zero to 2 yrs of age. DESIGN: An open-label study to evaluate efficacy and safety of cisatracurium as a continuous infusion in infants. SETTING: A tertiary pediatric intensive care unit. PATIENTS: Eleven children, 0-2 yrs of age, requiring prolonged neuromuscular blockade. INTERVENTIONS: Cisatracurium besylate, 0.1 mg/kg, was administered as an intravenous bolus dose and repeated if necessary until a >90% neuromuscular blockade, as determined by train-of-four response, was achieved. Patients were allowed to recover to 90% blockade (I/IV twitch) after the initial bolus and were administered continuous infusion at 2 &mgr;g/kg/min. The continuous infusion rate was adjusted to maintain a train-of-four response of 0-I/IV, with an increase in the rate preceded by a bolus dose of cisatracurium besylate. An electromyographic monitor was used to measure recovery at the end of infusion, when possible. Heart rate and blood pressure were recorded after the initial bolus dose and after changes in infusion rates. Blood samples were drawn at steady-state during cisatracurium infusion at several different times during the study and at the end of infusion for measurement of plasma cisatracurium and laudanosine concentrations. MEASUREMENTS AND MAIN RESULTS: The mean infusion rate of cisatracurium besylate required to maintain train-of-four response of 0-I/iv was 5.4 +/- 3.0 &mgr;g/kg/min. The mean total duration of infusion was 64.5 +/- 36 hrs. Ten percent and complete neuromuscular recovery occurred at 26.6 +/- 10.4 and 74.8 +/- 32 mins, respectively, after discontinuation of infusion. Mean cisatracurium and laudanosine concentrations were 342.5 +/- 169 and 163.3 +/- 116 ng/mL, respectively. Four (37%) patients had undetectable (<5 ng/mL) cisatracurium concentrations at the time of 100% neuromuscular recovery (train-of-four response of IV/IV or no fade at 50 mA on the electromyogram). No significant hemodynamic changes were observed during treatment with cisatracurium besylate (p <.05). CONCLUSIONS: A longer period of recovery from neuromuscular blockade was observed compared with reports of older children. Recovery from neuromuscular blockade after long-term use was not associated with any adverse events in the immediate postinfusion period. Cisatracurium besylate is a safe and effective neuromuscular blocking agent for children 0-2 yrs of age.

Prospective documentation of sedative, analgesic, and neuromuscular blocking agent use in infants and children in the intensive care unit: A multicenter perspective

OBJECTIVE: To describe the use of neuromuscular blocking agents (NMBA) in critically ill children. DESIGN: Prospective cohort study. SETTING: Two pediatric intensive care units (ICUs). PATIENTS: All children who received NMBA in the ICUs during the study year. INTERVENTIONS: None Measurements: Data on use of NMBA agents and concurrent use of narcotic and sedative agents were collected. Demographic and outcome information was also obtained. MAIN RESULTS: NMBAs were used for either short-term (<6 hrs) or long-term neuromuscular blockade in 6%-9% of patient ICU days and for long-term blockade in 14%-16% of ventilatory support days. The overall mortality rate among ICU patients who received NMBA was 18%. Choice of agent varied between ICUs; however, succinyl choline was used in only 1% of cases for short-term neuromuscular blockade. The most frequent indication for long-term NMBA use was facilitation of mechanical ventilatory support (49%). Among these children, 46% received high frequency oscillatory ventilation. Long-term neuromuscular blockade was most frequently monitored by clinical examination rather than peripheral nerve stimulation. Paralysis for >6 hrs after discontinuation of NMBA was significantly more common when the agent was administered as an infusion instead of as bolus doses. Myopathy after long-term use of NMBA was seen in only 1 patient (0.4%). Doses (mg/kg) of NMBA did not significantly vary by patient age, but they did increase over time. CONCLUSIONS: Use of NMBA is more common in critically ill children than in reported studies of critically ill adults. Use of NMBA in critically ill children is associated with high severity of illness and mortality rates. Choice of NMBA and method of administration varies among providers. Concurrent use of narcotic and sedative agents with NMBA is frequent, but medication choice also varies among medical providers.

Pediatric neuroanesthesia. Hydrocephalus

Hydrocephalus, one of the most common adult and pediatric neurosurgical disorders, is an abnormal accumulation of cerebrospinal fluid in the ventricular system as a result of obstruction to the flow of cerebrospinal fluid. Causes of hydrocephalus include congenital obstruction, hemorrhage, infection, cysts and tumors, and associated neural tube deformities (i.e., myelomeningocele, Arnold-Chiari malformation). Treatment of hydrocephalus involves surgical implantation of shunt systems to drain the cerebrospinal fluid. Anesthetic considerations involve attention to the possibility of increased intracranial pressure and prevention of aspiration through rapid-sequence intravenous induction and modest hyperventilation until the ventricles have been decompressed.

Pediatric eye emergencies

Anesthesia for pediatric eye emergencies is predicted on prevention of a rise in intraocular pressure and avoidance of extrusion of the intraocular contents in the setting of a full stomach. Sedation or general anesthesia is frequently necessary for adequate examination of the eye.

Neuromuscular blockade in children

Neuromuscular blocking agents (NMBAs) have been widely used to control patients who need to be immobilized for some kind of medical intervention, such as an invasive procedure or synchronism with mechanical ventilation. The purpose of this monograph is to review the pharmacology of the NMBAs, to compare the main differences between the neuromuscular junction in neonates, infants, toddlers and adults, and moreover to discuss their indications in critically ill pediatric patients. Continuous improvement of knowledge about NMBAs pharmacology, adverse effects, and the many other remaining unanswered questions about neuromuscular junction and neuromuscular blockade in children is essential for the correct use of these drugs. Therefore, the indication of these agents in pediatrics is determined with extreme judiciousness. Computerized (Medline 1990-2000) and active search of articles were the mechanisms used in this review.

Mature minors should have the right to refuse life-sustaining medical treatment

Imagine that you are a teenager and have cancer. You undergo a year of chemotherapy and after a brief return to normal life, you have a relapse. Your physician says that chemotherapy and radiation therapy could be tried, but a bone marrow transplant (BMT) is your only chance of a real cure. He tells you and your parents that you could die as a result of complications from the transplant, but without it you would only be expected to live one year. You and your family discuss the alternatives and decide to have the transplant. You ask what will happen if the BMT fails, but both your physician and your family tell you that right now you must fight to get better and not think negative thoughts. You do not ask any more questions.