Hemodynamic effects of ketamine in children undergoing cardiac catheterization

Perioperative and Anesthetic Considerations in Pediatric Valvar and Subvalvar Aortic Stenosis

Aortic stenosis (AS) is a common form of left ventricular outflow tract obstruction (LVOTO) in children with congenital heart disease. This review specifically considers the perioperative features of valvar (VAS) and subvalvar AS (subAS) in the pediatric patient. Although VAS and subAS share some clinical features and diagnostic approaches, they are distinct clinical entities with separate therapeutic options, which range from transcatheter intervention to surgical repair. We detail the pathophysiology of AS and highlight the range of treatment strategies with a focus on anesthetic considerations for the care of these patients before, during, and after intervention.

Comparison of dexmedetomidine and ketamine versus propofol and ketamine for procedural sedation in children undergoing minor cardiac procedures in cardiac catheterization laboratory

BACKGROUND

The ideal anaesthetic technique for management of paediatric patients scheduled to undergo cardiac catheterisation is still not standardised.

AIM

To compare the effects of ketamine-propofol and ketamine-dexmedetomidine combinations on hemodynamic parameters and recovery time in paediatric patients undergoing minor procedures and cardiac catheterisation under sedation for various congenital heart diseases.

MATERIAL AND METHODS

60 children of either sex undergoing cardiac catheterisation were randomly assigned into two groups Dexmedetomidine-ketamine group (DK) and Propofol-ketamine (PK) of 30 patients each. All patients were premedicated with glycopyrrolate and midazolam (0.05mg/kg) intravenously 5-10 min before anaesthetic induction. Group 'DK'received dexmedetomidineiv infusion 1 μg/kg over 10 min + ketamine1mg/kg bolus, followed by iv infusion of dexmedetomidine 0.5μg/kg/hr and of ketamine1 mg/kg/hr. Group 'PK' received propofol 1mg/kg and ketamine 1mg/kg/hr for induction followed by iv infusion of propofol 100 μg/kg/hr and ketamine 1 mg/kg/hr for maintenance. Haemodynamic parameters and recovery time was recorded postoperatively.

STATISTICAL ANALYSIS

Independent sample t test was used to compare the statistical significance of continuous variables of both the groups.Chi square test was used for numerical data like gender.Fischer exact test was applied for non parametric data like ketamine consumption.

RESULTS

We observed that heart rate in dexmedetomidine (DK) group was significantly lower during the initial 25 mins after induction compared to the propofol (PK) group. Recovery was prolonged in the DK group compared to the PK group (40.88 vs. 22.28 min). Even ketamine boluses consumption was higher in DK group.

CONCLUSION

Use of dexmedetomidine-ketamine combination is a safe alternative, without any hemodynamic orrespiratory effects during the cardiac catheterization procedure but with some delayed recovery.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.

Diagnostic Cardiac Catheterization in the Pediatric Population

Although the utility of diagnostic cardiac catheterization in the clinical setting has diminished over the last years, due to the emergence of noninvasive imaging modalities, such as echocardiography, magnetic resonance imaging and computed tomography, catheterization for diagnostic reasons still constitutes a valuable tool in certain parts in the workup of pediatric heart disease. As a result, awareness of the main aspects of diagnostic catheterization is of great importance for the clinical cardiologist. In this article, the main variables measured and the main actions performed during diagnostic cardiac catheterization in children are discussed.

Sedation and Analgesia in Pediatric Cardiac Critical Care

OBJECTIVES

This review will focus on the pharmacokinetics (with an emphasis on the context-sensitive half-time), pharmacodynamics, and hemodynamic characteristics of the most commonly used sedative/hypnotic, analgesic, and IV anesthetics used in cardiac intensive care. In addition, the assessment of pain and agitation and withdrawal will be reviewed.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSIONS

Children in the cardiac ICU often require one or more components of general anesthesia: analgesia, amnesia (sedation and hypnosis), and muscle relaxation to facilitate mechanical ventilation, to manage postoperative pain, to perform necessary procedures, and to alleviate fear and anxiety. Furthermore, these same children are often vulnerable to hemodynamic instability due to unique underlying physiologic vulnerabilities. An assessment of hemodynamic goals, postoperative procedures to be performed, physiologic vulnerabilities, and the intended duration of mechanical ventilation should be made. Based on this assessment, the optimal selection of sedatives, analgesics, and if necessary, muscle relaxants can then be made.

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.

Echocardiographic Assessment of the Alterations in Pulmonary Blood Flow Associated with Ketamine and Etomidate Administration in Children with Tetralogy of Fallot

BACKGROUND

Despite widespread uses of ketamine, the clinical studies determining its effect on pulmonary blood flow in children with tetralogy of Fallot (TOF) are lacking. Furthermore, the quantification of pulmonary blood flow is not possible in these patients, because pulmonary artery catheter is contraindicated. Therefore, the purpose of this study was to evaluate the changes in pulmonary blood flow by intra-operative transesophageal echocardiography after ketamine or etomidate administration in children with TOF.

METHODS

Eleven children each in the two clinical variants of TOF (group A-moderate to severe cyanosis; group B-mild to minimal cyanosis) undergoing intracardiac repair were prospectively studied after endotracheal intubation. A single bolus dose of ketamine (2 mg/kg) and etomidate (0.3 mg/kg) was administered in a random order after 15 minute interval. Hemodynamic, arterial blood gas, and echocardiographic measurements were obtained at 7 consecutive times (T) points (baseline, 1, 2, 4, 6, 8, and 15 minutes after drug administration).

RESULTS

Ketamine produced a significant reduction in VTI-T (velocity time integrals total of left upper pulmonary vein), RVOT-PG (right ventricular outflow tract peak gradient), and MG (mean gradient) in group A while those in group B had a significant increase in VTI-T, RVOT-PG, and RVOT-MG at time (T1, T2, T4, and T6; P = 0.00). This divergent behavior, however, was not observed with etomidate.

CONCLUSION

Etomidate does not change pulmonary blood flow. However, ketamine produces divergent effects; it increases pulmonary blood flow in children with minimal cyanosis and decreases pulmonary blood flow in children with moderate to severe cyanosis.

Hemodynamic response to ketamine in children with pulmonary hypertension

BACKGROUND

The safety of ketamine in children with pulmonary hypertension has been debated because of conflicting results of prior studies in which changes in mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) have been widely variable. The goal of this prospective study was to quantitate the effects of ketamine on pulmonary hemodynamics in a cohort of children with pulmonary hypertension under conditions in which variables such as airway/ventilatory management, FiO(2), and use of vasodilating anesthetics were controlled.

METHODS

The IRB approved this study of 34 children undergoing cardiac catheterization for pulmonary hypertension studies. Following anesthetic induction with sevoflurane and tracheal intubation facilitated by the administration of rocuronium 0.7-1 mg·kg(-1) iv, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg·kg(-1) iv (or 0.5 mg·kg(-1) po preoperatively) and remifentanil iv infusion 0.5-0.7 mcg·kg(-1) ·min(-1). Ventilation was mechanically controlled to maintain PaCO(2) 35-40 mmHg. When endtidal sevoflurane was 0% and FiO(2) was 0.21, baseline heart rate (HR), mean arterial pressure (MAP), mPAP, right atrial pressure (RAP), pulmonary artery occlusion pressure (PAOP), right ventricular end-diastolic pressure (RVEDP), cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance (SVRI), indexed pulmonary vascular resistance (PVRI), and cardiac index (CI) were calculated. Each child then received a bolus of ketamine 2 mg·kg(-1) infused over 2 min. Measurements and calculations were repeated 2 min after the conclusion of the infusion.

RESULTS

The mean (95% CI) increase in mPAP following ketamine was 2 mmHg (0.2, 3.7), which was statistically significant but clinically insignificant. PVRI and PVRI/SVRI did not change significantly. Hemodynamic changes did not differ among subjects with differing severity of pulmonary hypertension or between subjects chronically treated with pulmonary vasodilators or not.

CONCLUSION

Ketamine is associated with minimal, clinically insignificant hemodynamic changes in sedated, mechanically ventilated children with pulmonary hypertension.

Anesthetic Drugs in Congenital Heart Disease

The structural defects associated with the various forms of congenital heart disease lead to pathological and functional changes that place patients at risk for adverse events, and in fact the perioperative incidence of morbidity and mortality has been documented to be increased in children with congenital heart disease. Patients with congenital heart disease can present to the anesthesiologist in a relatively precarious state of balance of several hemodynamic factors, including preload, ventricular contractility, systemic vascular resistance, pulmonary vascular resistance, heart rate, and cardiac rhythm. Anesthetic drugs can affect each of these, and an ideal anesthetic drug for such patients does not exist. The purpose of this article is to review the hemodynamic effects of anesthetic drugs and how they may contribute to the occurrence of adverse events in children with congenital heart disease.

The anesthetic management of children with pulmonary hypertension in the cardiac catheterization laboratory

Children need cardiac catheterization to establish the diagnosis and monitor the response to treatment when undergoing drug therapy for the treatment of pulmonary arterial hypertension (PAH). Children with PAH receiving general anesthesia for cardiac catheterization procedures are at significantly increased risk of perioperative complications in comparison with other children. The most acute life-threatening complication is a pulmonary hypertensive crisis. It is essential that the anesthesiologist caring for these children understands the pathophysiology of the disease, how anesthetic medications may affect the patient's hemodynamics, and how to manage an acute pulmonary hypertensive crisis.

Anaesthetic management of the child with co-existing pulmonary disease

Children with co-existing pulmonary disease have a wide range of clinical manifestations with significant implications for anaesthetists. Although there are a number of pulmonary diseases in children, this review focuses on two of the most common pulmonary disorders, asthma and bronchopulmonary dysplasia (BPD). These diseases share the physiology of bronchoconstriction and variably decreased flow in the airways, but also have unique physiological consequences. The anaesthetist can make a difference in outcomes with proper preoperative evaluation and appropriate preparation for surgery in the context of a team approach to perioperative care with implementation of a stepwise approach to disease management. An understanding of the importance of minimizing the risk for bronchoconstriction and having the tools at hand to treat it when necessary is paramount in the care of these patients. Unique challenges exist in the management of pulmonary hypertension in BPD patients. This review covers medical treatment, intraoperative management, and postoperative care for both patient populations.

The comparison of the effect of three anesthetic induction regimens on the arterial oxygen saturation in children with tetralogy of fallot undergoing cardiac surgery

BACKGROUND

Tetralogy of fallot (TOF) is the most common cyanotic congenital heart disease. Anesthesia induction is a challenging issue in these patients due to the risk of worsening hypoxemia following decrease in pulmonary blood flow. We evaluated the effect of three anesthetic induction regimens on the arterial oxygen saturation (SaO2%) in children with TOF.

METHODS

Seventy six children aged 50 days to 15 years old with TOF, scheduled in Nemazee and Faghihi hospitals to undergo elective cardiac surgery during 1385-1388 were randomly divided into 3 groups to receive three anesthetic induction agents including ketamine (2 mg/kg, IV), ketamine (5 mg/kg, IM) and halothane for gas induction. SaO2% and heart rate were recorded before induction and thereafter every 1 minute during induction of anesthesia till 10 min post-induction.

RESULTS

There were not significant differences between three groups regarding pattern of changes in SaO2% during 10 min post-induction. All three groups showed an increase in SaO2% committed over 6th minute but this pattern was not seen after that time. In addition, there were not significant differences among groups according to heart rate in the study period.

CONCLUSION

It seems that anesthesia induction in TOF patients with ketamine IV and IM and halothane did not have significant adverse effects on SaO2%. Indeed, oxygenation during induction may offset other possible adverse effects of induction drugs on SaO2%.

Ketamine-etomidate for children undergoing cardiac catheterization

The purpose of this study was to determine the effects of combined low-dose ketamine and etomidate on hemodynamics during cardiac catheterization in children with congenital cardiac shunts. Sixty children undergoing routine diagnostic cardiac catheterization were included: 30 had a right-to-left shunt, and 30 had a left-to-right shunt. Both groups were given a single dose of etomidate 0.3 mg·kg(-1) with ketamine 1 mg·kg(-1). There were no hemodynamic changes in the group with a right-to-left shunt. In cases of left-to-right shunt, there were significant differences in heart rate, right atrial pressure, mean arterial pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, and systemic vascular resistance index. Decreases in pulmonary blood flow and pulmonary-systemic shunt ratio were also observed. Further studies are required with dose titration of this anesthetic combination in pediatric patients with congenital heart disease involving a left-to-right shunt.

Current approaches to pediatric heart catheterizations

Sedation for pediatric cardiac catheterization is a common requirement in many institutions. As the field of cardiac catheterization has evolved, the provision of sedation for these procedures has been varied. Increasingly the demand is for dedicated personnel focused on monitoring and delivery of sedation while in the catheterization suite. This article describes the considerations one must use when undertaking these cases.

Perioperative complications in children with pulmonary hypertension undergoing general anesthesia with ketamine

BACKGROUND

Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications in children, including pulmonary hypertensive crisis and cardiac arrest. Uncertainty remains about the safety of ketamine anesthesia in this patient population.

AIM

Retrospectively review the medical records of children with PAH to ascertain the nature and frequency of peri-procedural complications and to determine whether ketamine administration was associated with peri-procedural complications.

METHODS

Children with PAH (mean pulmonary artery pressure > or =25 mmHg and pulmonary vascular resistance index > or =3 Wood units) who underwent general anesthesia for procedures during a 6-year period (2002-2008) were enrolled. Details about the patient, PAH, procedure, anesthetic and postprocedural course were noted, including adverse events during or within 48 h of the procedure. Complication rates were reported per procedure. Association between ketamine and peri-procedural complications was tested.

RESULTS

Sixty-eight children (median age 7.3 year, median weight 22 kg) underwent 192 procedures. Severity of PAH was mild (23%), moderate (37%), and severe (40%). Procedures undertaken were major surgery (n = 20), minor surgery (n = 27), cardiac catheterization (n = 128) and nonsurgical procedures (n = 17). Ketamine was administered during 149 procedures. Twenty minor and nine major complications were noted. Incidence of cardiac arrest was 0.78% for cardiac catheterization procedures, 10% for major surgical procedures and 1.6% for all procedures. There was no procedure-related mortality. Ketamine administration was not associated with increased complications.

CONCLUSIONS

Ketamine appears to be a safe anesthetic option for children with PAH. We report rates for cardiopulmonary resuscitation and mortality that are more favorable than those previously reported.

Comparison of sevoflurane and ketamine for anesthetic induction in children with congenital heart disease

BACKGROUND

Sevoflurane is widely used in pediatric anesthesia for induction. Ketamine has been preferred in pediatric cardiovascular anesthesia. Aim of this study was to compare the hemodynamic effects and the speed of ketamine and sevoflurane for anesthesia induction in children with congenital heart disease.

MATERIALS AND METHODS

Children with congenital heart disease undergoing corrective surgery were included in the study. After oral premedication with midazolam (0.5 mg.kg(-1)), anesthesia induction was started with 5 mg.kg(-1) intramuscular ketamine (group K). In the second group, induction was achieved with sevoflurane (group S); the first concentration was 3% and increased after every three breaths. Intravenous access time and intubation times were enrolled for each child. Hemodynamic data and oxygen saturation were recorded every 2 min and any event during induction period was also noted.

RESULTS

Forty-seven children were included in the study; 23 in group K and 24 in group S. Heart rates and oxygen saturation values were similar between groups during the study. No difference was found between intravenous access time and intubation times. However, blood pressure levels were significantly lower in group S after recording baseline values till the intubation time (at 4, 6, and 8 min). Respiratory complications observed during the study were mild and were less frequent in group K than in group S (4 vs 13).

CONCLUSION

Ketamine appears a good alternative for induction in patients with congenital heart disease. It permits preservation of hemodynamic stability with minimal side effects.

Anesthetic management of children with pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications, including pulmonary hypertensive crisis and cardiac arrest. Several mechanisms of hemodynamic deterioration, including acute increases in pulmonary vascular resistance (PVR), alterations of ventricular contractility and function and coronary hypoperfusion can contribute to morbidity. Anesthetic drugs exert a variety of effects on PVR, some of which are beneficial and some undesirable. The goals of balanced and cautious anesthetic management are to provide adequate anesthesia and analgesia for the surgical procedure while minimizing increases in PVR and depression of myocardial function. The development of specific pulmonary vasodilators has led to significant advances in medical therapy of PAH that can be incorporated in anesthetic management. It is important that anesthesiologists caring for children with PAH be aware of the increased risk, understand the pathophysiology of PAH, form an appropriate anesthetic management plan and be prepared to treat a pulmonary hypertensive crisis.

Ketamine does not increase pulmonary vascular resistance in children with pulmonary hypertension undergoing sevoflurane anesthesia and spontaneous ventilation

BACKGROUND

The use of ketamine in children with increased pulmonary vascular resistance is controversial. In this prospective, open label study, we evaluated the hemodynamic responses to ketamine in children with pulmonary hypertension (mean pulmonary artery pressure >25 mm Hg).

METHODS

Children aged 3 mo to 18 yr with pulmonary hypertension, who were scheduled for cardiac catheterization with general anesthesia, were studied. Patients were anesthetized with sevoflurane (1 minimum alveolar anesthetic concentration [MAC]) in air while breathing spontaneously via a facemask. After baseline catheterization measurements, sevoflurane was reduced (0.5 MAC) and ketamine (2 mg/kg IV over 5 min) was administered, followed by a ketamine infusion (10 microg x kg(-1) x min(-1)). Catheterization measurements were repeated at 5, 10, and 15 min after completion of ketamine load. Data at various time points were compared (ANOVA, P < 0.05).

RESULTS

Fifteen patients (age 147, 108 mo; median, interquartile range) were studied. Diagnoses included idiopathic pulmonary arterial hypertension (5), congenital heart disease (9), and diaphragmatic hernia (1). At baseline, median (interquartile range) baseline pulmonary vascular resistance index was 11.3 (8.2) Wood units; 33% of patients had suprasystemic mean pulmonary artery pressures. Heart rate (99, 94 bpm; P = 0.016) and Pao2 (95, 104 mm Hg; P = 007) changed after ketamine administration (baseline, 15 min after ketamine; P value). There were no significant differences in mean systemic arterial blood pressure, mean pulmonary artery pressure, systemic or pulmonary vascular resistance index, cardiac index, arterial pH, or Paco2.

CONCLUSIONS

In the presence of sevoflurane, ketamine did not increase pulmonary vascular resistance in spontaneously breathing children with severe pulmonary hypertension.

Dexmedetomidine-Ketamine and Propofol-Ketamine Combinations for Anesthesia in Spontaneously Breathing Pediatric Patients Undergoing Cardiac Catheterization

OBJECTIVE

The purpose of this study was to compare the effects of dexmedetomidine-ketamine and propofol-ketamine combinations on hemodynamics, sedation level, and the recovery period in pediatric patients undergoing cardiac catheterization.

DESIGN

Prospective, randomized trial.

SETTING

University hospital.

PARTICIPANTS

Children (n = 44) undergoing cardiac catheterization.

INTERVENTIONS

The dexmedetomidine plus ketamine group (group 1, n = 22) received an infusion over 10 minutes of 1 microg/kg of dexmedetomidine and ketamine, 1 mg/kg, as a bolus, for induction. The patients then received an infusion of 0.7 microg/kg/h of dexmedetomidine and 1 mg/kg/h of ketamine for maintenance. The propofol plus ketamine group (group 2, n = 22) received 1 mg/kg of propofol and 1 mg/kg of ketamine for induction. The patients received 100 microg/kg/min of propofol and 1 mg/kg/h of ketamine by infusion for maintenance. Additional doses of ketamine, 1 mg/kg, were administered when a patient showed discomfort in both groups.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic data, respiratory rate, bispectral index, and sedation scores were recorded after induction and every 15 minutes thereafter. The time to reach a Steward recovery score of 6 was recorded. The heart rate in group 1 was significantly lower (average 10-20 beats/min) than group 2 after induction and throughout the procedure. Ketamine consumption in group 1 was significantly more than in group 2 (2.03 mg/kg/h v 1.25 mg/kg/h) for maintenance (p < 0.01). The recovery time was also longer in group 1 than in group 2 (49.54 v 23.16 minutes, respectively; p < 0.01).

CONCLUSIONS

The dexmedetomidine-ketamine combination was not superior to a propofol-ketamine combination because of insufficient sedation and analgesia and a longer recovery time.

Efficacy of nitroglycerin inhalation in reducing pulmonary arterial hypertension in children with congenital heart disease

BACKGROUND

There has been a renewed interest in nitric oxide donor drugs, such as nitroglycerin, delivered by the inhalational route for treatment of pulmonary arterial hypertension (PAH). We investigated the acute effects of inhaled nitroglycerin on pulmonary and systemic haemodynamics in children with PAH associated with congenital heart disease.

METHODS

Nineteen children with acyanotic congenital heart disease and a left to right shunt with severe PAH, undergoing routine diagnostic cardiac catheterization were included in this study. Systolic, diastolic and mean systemic as well as pulmonary artery pressures, right atrial pressure and pulmonary capillary wedge pressure (PCWP) were recorded and systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) were calculated at room air, following 100% oxygen as well as after nitroglycerin inhalation in all patients.

RESULTS

Systolic, diastolic and mean pulmonary artery pressure and PVRI decreased significantly, whereas heart rate, systolic, diastolic and mean systemic arterial pressure, PCWP and SVRI did not change significantly following 100% oxygen or inhalation of nitroglycerin.

CONCLUSION

Inhaled nitroglycerin significantly decreases systolic, diastolic and mean pulmonary artery pressure as well as PVRI without affecting systemic haemodynamics, and thus can be used as a therapeutic modality for acute reduction of PAH in children with congenital heart disease.

Propofol and propofol-ketamine in pediatric patients undergoing cardiac catheterization

We investigated the effects of propofol and propofol-ketamine on hemodynamics, sedation level, and recovery period in pediatric patients undergoing cardiac catheterization. We performed a prospective, randomized, double-blind study. The study included 60 American Society of Anesthesiologists physical status II or III (age range, 1 month-13 years) undergoing cardiac catheterization for evaluation of congenital heart disease. Propofol and ketamine were prepared in 5% glucose solution to a final concentration of 5 and 1 mg/ml, respectively; similar injectors containing 5% glucose solution only were prepared. Fentanyl (1 microg/kg) and propofol (1.5 mg/kg) were given to both groups. Then, group 1 received 0.5 ml/kg of 5% glucose and group 2 0.5 ml/kg of ketamine solution by an anesthesiologist who was unaware of the groups of patients. Local anesthesia with 1% lidocaine was administered before intervention in all patients. The noninvasively measured mean arterial pressure, heart rate, respiratory rate, and peripheral oxygen saturation were recorded at the baseline, following drug administration, at 3, 5, 10, 15, 20, and 30 minutes and then at 15-minute intervals until the end of the procedure. Additional drug and fentanyl requirements to maintain a sedation level of 4 or 5 were recorded. After the procedure, the time to a Steward recovery score of 6 and adverse effects in the first 24 hours were recorded. The number of patients with more than a 20% decrease in mean arterial pressure was 11 in group 1 and 3 in group 2 (p < 0.05). The number of patients who experienced more than a 20% decrease in heart rate was 12 in group 1 and 5 in group 2 (p = 0.054). Ten patients in group 1 and 3 patients in group 2 required additional fentanyl doses (p = 0.057). The number of additional propofol doses was lower in group 2 (p < 0.05). Propofol combined with low-dose ketamine preserves mean arterial pressure better without affecting the recovery and thus is a good option in pediatric patients undergoing cardiac catheterization.

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.

Amnestic agents in pediatric bronchoscopy

STUDY OBJECTIVE

To assess the risk for complications with the use of sedation and analgesia techniques in pediatric fiberoptic bronchoscopy.

DESIGN

A retrospective case series.

SETTING

The ICU of a 325-bed tertiary care research hospital.

PATIENTS

Patients from 1 to 18 years of age who underwent fiberoptic bronchoscopy with BAL or transbronchial biopsy between June 1991 and December 1995 and received IV sedation and analgesia.

INTERVENTIONS

None.

METHODS

A retrospective chart review was performed. Extracted data included anesthetics and sedatives used and their per kilogram dosages, procedure durations, and complications including oxygen desaturations < 90%, vital sign alterations that required intervention, and emergence reactions to ketamine.

RESULTS

A total of 103 bronchoscopies were performed on 64 patients. Ketamine was used as the primary anesthetic in 60 procedures (58%). A combination of fentanyl and midazolam was used in 38 of the 43 remaining procedures. A variety of combinations were used in the five remaining procedures. Complications occurred in 13 procedures and included oxygen desaturations, stridor, cough, apnea, and nasal bleeding. Twelve of the 13 complications occurred in patients with a diagnosis of HIV infection. Eight of the13 complications involved children < or = 3 years of age.

CONCLUSIONS

Pediatric bronchoscopy is a safe and valuable procedure. However, in this study, anesthetic selection was shown to adversely affect the complication rate in the subsets of children < or = 3 years of age and with an underlying diagnosis of HIV infection.

Anesthetic regimen effects on a pediatric porcine model of asphyxial arrest

The effects of three anesthetic regimens on an established model of pediatric porcine hypoxic-hypercarbic arrest were examined. Twenty-four preadolescent miniature piglets were paralyzed, mechanically ventilated and anesthetized with one of three regimens: IM + IV pentobarbital (n = 8); IM + IV ketamine (n = 8); or IM ketamine+inhaled isoflurane (n = 8). Asphyxial cardiopulmonary arrest was induced and, after and 8 min cardiac arrest nonintervention interval, a standardized protocol of manual CPR with mechanical ventilation was performed. Outcome variables included incidence of ventricular fibrillation, time to cardiac arrest, endogenous plasma epinephrine levels and arteriovenous epinephrine gradients. IV Ketamine anesthesia produced the highest incidence of ventricular fibrillation (P < 0.01 vs. pentobarbital and isoflurane). Time to asphyxia induced cardiac arrest was greatest for the pentobarbital group (P < 0.05 vs. ketamine and isoflurane). During induction of asphyxial cardiac arrest (low cardiac flow), endogenous venous epinephrine accumulation was highest in the pentobarbital anesthetized group (P < 0.05). After 8 min of untreated cardiac arrest and 1 min of CPR (low flow), arterial epinephrine levels were highest in the ketamine group (P < 0.05). Endogenous epinephrine gradients were venous > arterial in all groups at the end of the 8 min cardiac arrest non-intervention interval (no flow). After 1 min of CPR, the gradients had either equalized or reversed to arterial > venous in all groups except for pentobarbital. As designed and expected, return of spontaneous circulation did not occur in any animal. We conclude that, in developing models of porcine asphyxial cardiopulmonary arrest and resuscitation to simulate pediatric human arrest, variations in anesthetic regimen produce significant differences in parameters that are important to consider: time to asphyxia induced cardiac arrest, fibrillation threshold, plasma epinephrine level and arteriovenous epinephrine gradient. Anesthetic effects need to be carefully considered and clearly explained to facilitate the interpretation of studies of interventions in cardiopulmonary arrest and resuscitation.

Adverse cardiovascular effects of ketamine infusion in patients with catecholamine-dependent heart failure

The longterm effects of ketamine on haemodynamic parameters and exogenous catecholamine requirements were studied in twenty-five critically ill patients with catecholamine-dependent heart failure. Following sedation with midazolam (0.15 +/- 0.07, mg.kg-1.h-1) and sufentanil (0.88 +/- 0.33 microgram.kg-1.h-1), patients with impaired left ventricular function (left ventricular ejection fraction area 30 +/- 7%) were randomly assigned to receive ketamine (2.5 +/- 0.9 mg.kg-1.h-1) and midazolam (Group A) or remained on sufentanil/midazolam (Group B). Haemodynamic measurements were performed throughout the first 24 hours after randomization. In group A cardiac index decreased by 21% (P = 0.01), mean arterial pressure increased by 13% (P = 0.01), mean pulmonary artery pressure by 14% (P = 0.04), pulmonary capillary wedge pressure by 20% (P = 0.03), and systemic vascular resistance index by 38% (P < 0.001). No significant cardiovascular effects were observed in Group B. Neither group had significant changes of exogenous catecholamine requirement. In conclusion, ketamine exhibits potential negative cardiovascular effects in patients with catecholamine-dependent heart failure. Therefore, ketamine should not be considered a first line drug for longterm sedation of patients with impaired left ventricular function.

Hemodynamic effects of ketamine, hypoxia and hyperoxia in children with surgically treated congenital heart disease residing greater than or equal to 1,200 meters above sea level

Little data are available on the hemodynamic effects of premedications and anesthetic agents on infants and children. Ketamine is the most frequently used anesthetic agent for cardiac catheterization procedures in pediatric patients with congenital heart disease. Previous reports both suggest and deny ketamine's pulmonary vasoreactive effects. Since the advent of sophisticated noninvasive equipment, one of the few indications for cardiac catheterization is to obtain accurate pressure data. If ketamine alters pulmonary vascular resistance, it would negate the primary reason for the procedure. Because the patient population studied herein resides greater than or equal to 1,200 meters above sea level, concerns about pharmacologic effects on pulmonary vascular resistance are enhanced. Simultaneous pulmonary artery and aortic pressures, thermodilution cardiac outputs, and blood gases were measured in room air (16% oxygen) and with ketamine infusion in 14 patients at cardiac catheterization. Reaction to hypoxia identified 3 groups: normal, intermediate and hyperresponders. The normal responders had normal resistance ratios (0.11) in room air and had little resistance ratio response to hypoxia (+0.02), hyperoxia (-0.03) or ketamine (+0.01). The intermediate responders had a slightly higher but normal resistance ratio (0.20) in room air, and a moderate reaction to hypoxia (+0.13), hyperoxia (-0.08) and ketamine (+0.11). The hyperresponders had an elevated resistance ratio (0.42) in room air and a striking reaction to hypoxia (+0.65), hyperoxia (-0.17) and ketamine (+0.49). Hypoxia and ketamine have a greater effect on resistance ratio than hypoxia alone in patients with reactive pulmonary vascular beds. Ketamine should not be used in children undergoing procedures to establish operability based on pulmonary vascular resistance or pulmonary vascular reactivity.