Anaesthetic experience with paediatric interventional cardiology

Use of analgesic and sedative drugs in the NICU: integrating clinical trials and laboratory data

Recent advances in neonatal intensive care include and are partly attributable to growing attention for comfort and pain control in the term and preterm infant requiring intensive care.Limitation of painful procedures is certainly possible, but most critically ill infants require unavoidable painful or stressful procedures such as intubation, mechanical ventilation, or catheterization.Many analgesics (opioids and nonsteroidal anti-inflammatory drugs)and sedatives (benzodiazepines and other anesthetic agents) are available but their use varies considerably among units. This review summarizes current experimental knowledge on the effects of sedative and analgesic drugs on brain development and reviews clinical evidence that speaks for or against the use of common analgesic and sedative drugs in the NICU but avoids any discussion of anesthesia during surgery. Risk/benefit ratios of intermittent boluses or continuous infusions for the commonly used sedative and analgesic agents are discussed in the light of clinical and experimental studies. The limitations of extrapolating experimental results from animals to humans must be considered while making practical recommendations based on the currently available evidence.

Evaluation of propofol-ketamine anesthesia for children undergoing cardiac catheterization procedures

The aim of this study was to assess the safety and efficacy of the continuous intravenous administration of a combination of propofol and ketamine for children undergoing cardiac catheterization procedures (CCP). Thirty-two children scheduled for CCP in a university teaching hospital were included in this prospective randomized study. Patients in group 1 (n = 15) were given a combination of propofol (25 microg/kg per minute) and ketamine (25 microg/kg per minute), whereas patients in group 2 (n = 17) received a combination of propofol (25 microg/kg per minute) and ketamine (12.5 microg/kg per minute) for the maintenance of anesthesia. There were no statistically significant differences with age, weight, duration of the procedure, and the number of diagnostic and interventional procedures between the two groups. There was no hemodynamic instability, airway compromise, excessive salivation, or arterial desaturation in either of the two groups. There was more incidence of movements in patients who received less dose of ketamine; however, it did not reach to statistically significant level. The total dose of ketamine used in group 1 was 309.25 +/- 90.97 microg/min, whereas in group 2, it was 148.06 +/- 34.05 microg/min. The time to awakening was significantly less in group 2 (P < 0.05). We conclude that a combination of propofol (25 microg/kg per minute) and two different doses of ketamine (25 and 12.5 microg/kg per minute, respectively) are safe and efficacious for CCP in children. Although the time to awaken was more in patients receiving 25 microg/kg per minute of ketamine compared to those receiving 12.5 microg/kg per minute of ketamine, it was well within acceptable limits.

Analgesia and local anesthesia during invasive procedures in the neonate

BACKGROUND

Preterm and full-term neonates admitted to the neonatal intensive care unit or elsewhere in the hospital are routinely subjected to invasive procedures that can cause acute pain. Despite published data on the complex behavioral, physiologic, and biochemical responses of these neonates and the detrimental short- and long-term clinical outcomes of exposure to repetitive pain, clinical use of pain-control measures in neonates undergoing invasive procedures remains sporadic and suboptimal. As part of the Newborn Drug Development Initiative, the US Food and Drug Administration and the National Institute of Child Health and Human Development invited a group of international experts to form the Neonatal Pain Control Group to review the therapeutic options for pain management associated with the most commonly performed invasive procedures in neonates and to identify research priorities in this area.

OBJECTIVE

The goal of this article was to review and synthesize the published clinical evidence for the management of pain caused by invasive procedures in preterm and full-term neonates.

METHODS

Clinical studies examining various therapies for procedural pain in neonates were identified by searches of MEDLINE (1980-2004), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2004), the reference lists of review articles, and personal files. The search terms included specific drug names, infant-newborn, infant-preterm, and pain, using the explode function for each key word. The English-language literature was reviewed, and case reports and small case series were discarded.

RESULTS

The most commonly performed invasive procedures in neonates included heel lancing, venipuncture, IV or arterial cannulation, chest tube placement, tracheal intubation or suctioning, lumbar puncture, circumcision, and SC or IM injection. Various drug classes were examined critically, including opioid analgesics, sedative/hypnotic drugs, nonsteroidal anti-inflammatory drugs and acetaminophen, injectable and topical local anesthetics, and sucrose. Research considerations related to each drug category were identified, potential obstacles to the systematic study of these drugs were discussed, and current gaps in knowledge were enumerated to define future research needs. Discussions relating to the optimal design for and ethical constraints on the study of neonatal pain will be published separately. Well-designed clinical trials investigating currently available and new therapies for acute pain in neonates will provide the scientific framework for effective pain management in neonates undergoing invasive procedures.

Incidents and complications during pediatric cardiac catheterization

BACKGROUND

Cardiac catheterization has revolutionized the management of pediatric cardiac disease. There has been little information on adverse events during these cases from an anesthesia viewpoint. The aim of this audit was to determine the incident rate during pediatric cardiac catheterization as contemporaneously reported by the anesthetist and to identify both the types of events and which procedures had the highest risk.

METHODS

Since 1993, data have been collected prospectively on an audit form for every anesthetic given in our institution, and in-theatre events were recorded on this form. We have reviewed the data collected on pediatric cardiac catheterizations over a period of 9 years.

RESULTS

A total of 4454 cardiac catheterizations were recorded. The overall incidence of events was 9.3%. Cardiac catheterization with occlusion of a patent ductus arteriosus (PDA) or a secundum atrial septal defect (ASD) had the lowest event rate at 4.2%. The figure for cardiac catheterization with other therapeutic interventions was 11.6 and 9.3% for solely diagnostic cardiac catheterization. The event rate in infants under the age of 1 year was 13.9% compared with 6.7% for those children over the age of 1 year. Of the 253 reports from cardiac catheterizations that could be analyzed further, there were 91 major complications including four deaths, 72 minor complications and 90 other incidents.

CONCLUSIONS

Adverse events occur more commonly during cardiac catheterization than during pediatric anesthesia in general. Cases with highest risk are those in the under 1 year olds and those including a therapeutic intervention other than PDA or ASD occlusion.

Which anesthetic agent alters the hemodynamic status during pediatric catheterization? comparison of propofol versus ketamine

OBJECTIVE

To compare the effects of propofol and ketamine on systemic and pulmonary circulations in pediatric patients scheduled for elective cardiac catheterization.

DESIGN

Prospective, randomized, and blinded.

SETTING

University hospital.

PARTICIPANTS

Children (n = 41) undergoing cardiac catheterization.

INTERVENTIONS

All children were premedicated with oral midazolam 60 minutes before the procedure. Patients were separated into 3 groups according to shunts diagnosed by transthoracic echocardiography before the catheterization procedure: patients without cardiac shunt (Group I, n = 11), left-to-right shunt (Group II, n = 12), and right-to-left shunt (Group III, n = 18). A continuous infusion of propofol (100-200 microg/kg/min) or ketamine (50-75 microg/kg/min) was randomly started in all groups to obtain immobility during the procedure. Hemodynamic data, including systemic venous, pulmonary artery and vein, aortic saturations and pressures, were recorded; Qp/Qs were calculated. The same set of data was recorded before discontinuation of infusions at the end of the procedure.

MEASUREMENTS AND MAIN RESULTS

After the propofol administration, in all 3 patient groups propofol infusion was associated with significant decreases in systemic mean arterial pressure. In groups with cardiac shunts (Group II and III), propofol infusion significantly decreased systemic vascular resistance and increased systemic blood flow, whereas pulmonary vascular resistance and pulmonary blood flow did not change significantly. These changes resulted in decreased left-to-right shunting and increased right-to-left shunting; the pulmonary-to-systemic flow ratio decreased significantly. On the other hand, after ketamine infusion, systemic mean arterial pressure increased significantly in all patient groups, but pulmonary mean arterial pressure, systemic vascular resistance, and pulmonary vascular resistance were unchanged.

CONCLUSION

In children with cardiac shunting, the principal hemodynamic effect of propofol is a decrease in systemic vascular resistance. In children with intracardiac shunting, this results in an increase in right-to-left shunting and a decrease in the ratio of pulmonary to systemic blood flow, which may lead to arterial desaturation. Ketamine did not produce these changes. The authors suggested that during cardiac catheterization in children, both the anesthesiologists and cardiologists need to know that anesthetic agents can significantly alter the hemodynamic status in children with complex congenital heart defects and affect the results of hemodynamic calculations that are important for decision-making and treatment of these patients.

Ketamine for short ambulatory procedures in children: an audit

BACKGROUND

The purpose of this audit was the evaluation of recovery and discharge times and the identification of perioperative events related to anaesthetics with intravenous ketamine and midazolam.

METHODS

In our institution, we use this method as a routine technique for short ambulatory emergency or elective procedures. Two hundred children, aged 1-16 years, were included. Ninety percent of the study patients underwent emergency procedures.

RESULTS

Most perioperative events were minor and easily corrected. Intraoperatively, most events were related to respiration, including oxygen desaturation, apnoea or laryngospasm. Vomiting, vertigo, visual disturbances, nightmares and hallucinations were observed in the postoperative period. Serious complications requiring hospital admission or further interventions in the postoperative period were rare. Mean recovery time was 100 min (range 20-325) and mean discharge time 130 min (range 25-360).

CONCLUSIONS

Intravenous ketamine plus midazolam is a suitable, simple and fast anaesthetic technique for short, painful ambulatory procedures. Considering the possibility of potentially serious respiratory complications, it should be performed only by qualified anaesthesia staff who are trained in advanced airway management.

Pediatric sedation for procedures titrated to a desired degree of immobility results in unpredictable depth of sedation

OBJECTIVE

To test the hypothesis that the need to attain immobility during pediatric sedation for procedures determines the depth of sedation, which cannot always be predicted.

DESIGN

A retrospective review of sedation documents of 301 consecutive sedations of pediatric patients undergoing various procedures

SETTING

Division of Critical Care sedation service within a children's hospital.

MEASUREMENTS AND MAIN RESULTS

The medical records and sedation forms of our most recent 301 consecutive sedations were retrospectively reviewed. Based on the data gathered, the patients were categorized according to their achieved level of immobility, their level of consciousness according to the definitions of the American Academy of Pediatrics, the procedures for which sedation was administered, and the sedatives used. A total of 125 males and 89 females received 301 sedations. Their ages ranged from 22 days to 29 years (mean 7 y + 6 y). We recognized four categories of immobility for procedures. In category 1, some motion was allowed during painless and noninvasive procedures to the extent that it did not risk the patient nor hinder the successful performance of the procedures. In category 2, the patients were kept motionless during painless and noninvasive procedures. In category 3, the patients were kept motionless during painful and invasive procedures with the addition of local anesthetic. In category 4, the patients remained motionless throughout their painful or invasive procedure without the use of local anesthetics. There were 32, 10, 156 and 103 sedations in each category, respectively. Conscious sedation (CS) was observed in six sedations (19%) in category 1 of immobility; it was observed in none (0%) in category 2, in 4 sedations (2.6%) in category 3, and in 1 sedation (1%) in category 4. Deep sedation (DS) was noted in 26 category 1 sedations (81%), in 10 category 2 sedations (100%), in 136 category 3 sedations (87%), and in 63 category 4 sedations (61%). General anesthesia (GA) was only observed in categories 3 and 4 in 16 sedations (10%) and 39 sedations (38%), respectively. Intravenous (IV) ketamine, as a single agent or in combination with other agents, was the most frequently used sedative (88%) followed by IV benzodiazepines (64%), propofol (39%), opiates (15%), and barbiturates (5%). A total of 59 (19%) adverse events were encountered during the 301 sedations. In categories 1 and 2, no adverse event (0%) was encountered. In category 3, 19 adverse events took place (32%), and 40 adverse events (68%) (P< 0.05) occurred in category 4.

CONCLUSIONS

Pediatric sedation results in 4 categories of immobility. Complete immobility during painful and invasive procedures is associated with a higher incidence of adverse events. The depth of sedation (ie, CS, DS, or GA) required to achieve each category of immobility is unpredictable and varies from patient to patient. Thus, granting a limited sedation authority (conscious sedation only) to physicians may be of limited practical value.

One center's experience with remifentanil infusions for pediatric cardiac catheterization

OBJECTIVE

To investigate the efficacy of a remifentanil infusion for pediatric cardiac catheterization.

DESIGN

Prospective.

SETTING

University hospital.

PARTICIPANTS

Children undergoing cardiac catheterization (n = 55).

INTERVENTIONS

All patients (age range, 2 months to 12 years) were premedicated with an oral mixture of hydroxyzine and midazolam 60 minutes before the procedure. A remifentanil infusion was initiated at 0.1 microg/kg/min before the start of cardiac catheterization. Noninvasive systolic blood pressure, heart rate, oxygen saturation (SpO(2)), respiratory rate, and sedation score were recorded before the remifentanil infusion and every 15 minutes thereafter throughout the procedure. Episodes of apnea, vomiting, pruritus, and muscle rigidity and recovery time were noted.

MEASUREMENTS AND MAIN RESULTS

There were no significant changes in systolic blood pressure, heart rate, SpO(2), or respiratory rate during the procedure. The sedation scale scores at 30, 45, 60, 75, and 90 minutes of remifentanil infusion were significantly lower than the scores recorded at baseline and 15 minutes. In 23 patients, the remifentanil infusion maintained a satisfactory level of sedation, but 32 patients required additional drugs (18 received midazolam, and 14 received midazolam plus ketamine). Recovery was rapid after the remifentanil infusion was discontinued, with a mean time of 2.04 +/- 2.32 minutes to reach a recovery score of > or =5. Three patients experienced apnea after bolus doses of remifentanil, 1 patient vomited, and 1 patient complained of pruritus.

CONCLUSION

In pediatric cases in which other intravenous analgesics and sedatives are contraindicated, remifentanil infusion appears to be a suitable alternative based on its associated rapid recovery and stable hemodynamics.

Sedation/Analgesia for diagnostic and therapeutic procedures in children

Sedation/analgesia for diagnostic and therapeutic procedures in children has been associated with life-threatening adverse events. Reports of adverse events and recognition of wide variability in sedation practices has led to the development of guidelines and standards of care to ensure the safety of sedated children. The safety of sedated children can be enhanced by detailed presedation evaluation, careful patient selection, and the use of drugs with a wide margin of safety that are carefully titrated to desired depth of sedation by trained personnel. Once sedative drugs are administered, stringent monitoring, including continuous pulse oximetry and frequent assessment of vital signs and sedation depth, will permit early recognition of untoward drug effects and permit early intervention. Children with underlying medical conditions, such as airway abnormalities, may not be suitable subjects for sedation and may require consideration for general anesthesia to aid their procedure. Although significant strides have been made in recognition of the risks of sedation and in development of guidelinesfor safe sedation practices, further work must focus on development of newer sedation regimens with shorter-acting drugs and wider margins of safety.

Total intravenous anesthesia with ketamine for pediatric interventional cardiac procedures

OBJECTIVE

To evaluate the safety and efficacy of ketamine in pediatric patients undergoing interventional cardiac procedures.

DESIGN

A retrospective clinical study.

SETTING

A single, tertiary referral center.

PARTICIPANTS

Patients (n = 107) undergoing interventional cardiac procedures between July 1996 and July 1998.

INTERVENTIONS

Each patient received a bolus of ketamine, 1 mg/kg intravenously, followed by an infusion of 50 to 75 microg/kg/min for the duration of the procedure.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic and respiratory parameters were noted. All patients were breathing spontaneously. Average infusion dose of ketamine was 51.40+/-3.54 microg/kg/min (mean +/- standard deviation). Increases in heart rate and mean arterial pressure by more than 20% from baseline values were seen in 10 and 9 patients, respectively. Transient apnea and excessive salivation were seen in two patients each. Excessive movement of extremities was seen in six patients. There were no episodes of unpleasant dreams or hallucinations. There were two deaths (1.9%) related to the interventional procedures.

CONCLUSION

The technique described is a simple, safe, and effective method for anesthetizing children in the cardiac catheterization laboratory for interventional procedures.

Intramuscular ketamine for pediatric sedation in the emergency department: safety profile in 1,022 cases

STUDY OBJECTIVE

To determine the safety of intramuscular ketamine when administered by emergency physicians for pediatric procedures in accordance with a defined protocol.

METHODS

We assembled a consecutive case series of children aged 15 years or younger who were given ketamine in the emergency departments of a university medical center and an affiliated county hospital over a 9-year period. A protocol for ketamine use (4 mg/kg, intramuscularly) was followed. Treating physicians were instructed to complete data forms recording complications and adequacy of sedation concurrent with patient care. Subsequent chart review was used to determine indications, adjunctive drugs, time to discharge, and adverse reactions for all patients.

RESULTS

Intramuscular ketamine was administered 1,022 times, mainly for laceration repair and fracture reduction. Physicians completed data forms for 431 of treated children (42%). Transient airway complications occurred in 1.4%: airway malalignment (n = 7), laryngospasm (n = 4), apnea (n = 2), and respiratory depression (n = 1). All were quickly identified and treated without intubation or sequelae. Emesis occurred in 6.7%, without evidence of aspiration. Mild recovery agitation occurred in 17.6%, moderate to severe agitation in 1.6%. No child required hospitalization for complications caused by ketamine. Ketamine produced acceptable sedation in 98% of patients. The median time from injection to emergency department discharge was 110 minutes for children given a single dose of ketamine.

CONCLUSION

Intramuscular ketamine may be administered safely by emergency physicians to facilitate pediatric procedures in accordance with a defined protocol and with appropriate monitoring. Ketamine is highly effective, has a wide margin of safety, does not require intravenous access, and uniquely preserves protective airway reflexes.

Paediatric cardiac catheterization: innovations

In recent years interventional procedures have been introduced to the field of paediatric cardiac catheterization. These procedures continue to develop in complexity and increasingly are being applied to patients with reduced cardiovascular reserve, as an alternative to cardiac surgery or when cardiac surgery with cardiopulmonary bypass is contraindicated. More frequently anaesthetists are being called upon to provide support in sedating, anaesthetizing or/and resuscitating these patients. The purpose of this review is to give a comprehensive update of the interventional procedures and to review the anaesthetic management techniques as they apply to the catheterization laboratory. We will discuss possible complications and management strategies from our own experience and the experience of others. We have observed that as more complicated procedures are performed the anaesthetist plays a pivotal role in the management of the patient from arrival to departure from the cardiac catheterization laboratory, and in preventing mortality and major morbidity. Although the economic consequences of interventional cardiological techniques remain unclear, the field continues to expand and more complex procedures are continually being introduced.

Ventilation during total intravenous anaesthesia with ketamine

Total intravenous anaesthesia with ketamine (TIVAK) is widely used throughout the world especially in precarious conditions. Although ketamine is usually considered to provide good respiratory function and may be used with spontaneous ventilation, recent studies have shown that desaturations may occur. Seventy-six adults and 64 children scheduled for peripheral surgery were randomly allocated to breathe spontaneously room air or 40% oxygen during TIVAK. Pulse oximetry was continuously assessed during anaesthesia and recovery. Desaturation (SpO2 < 92%) occurred immediately after induction in 20 adults breathing air and in only three adults breathing oxygen (P < 0.05). Respiratory abnormalities were sufficiently severe to warrant tracheal intubation in two patients. Desaturations were not observed during the recovery period. Very similar results were observed in children although desaturations observed after induction in paediatric patients breathing room air were less frequent than in adults occurring in only nine patients. These desaturations were also less severe and never required tracheal intubation. The high incidence of arterial desaturation observed immediately after induction of anaesthesia with intravenous ketamine should prompt anaesthetists to provide oxygen in every adult patient at least for the first 15 min. The large decrease in SpO2 sometimes observed requires that trained personnel be present and that equipment for tracheal intubation be available.

Alfentanil and fentanyl sedation in infants and small children during cardiac catheterization

Thirty patients aged 1-23 mth received either alfentanil or fentanyl for the induction and maintenance of IV sedation during cardiac catheterization following oral flunitrazepam premedication (0.1 mg.kg-1). Patients breathed spontaneously 30 per cent oxygen in air. Both alfentanil and fentanyl abolished all reaction to pain and discomfort with minimal haemodynamic and respiratory changes. Induction doses of alfentanil and fentanyl were 20 +/- 6 and 2.5 +/- 1.1 (mean +/- SD) micrograms.kg-1, respectively, and maintenance requirements 30 +/- 12 and 1.5 +/- 0.6 micrograms.kg-1.h-1, respectively. These requirements were comparable among younger and older as well as cyanotic and acyanotic patients. The IV sedation described adds an effective method to the armamentarium of an anaesthetist working in the cardiac laboratory.