Comparative hemodynamic depression of sevoflurane versus halothane in infants: an echocardiographic study

The halothane era in pediatric anesthesia: The convergence of a cardiac depressant anesthetic with the immature myocardium of infancy

Introduced in the late 1950s, halothane became the anesthetic of choice for inhalational induction of children for over 40 years. Halothane enjoyed a generally favorable safety record during its time, but its cardiac contractility depressant effect-well tolerated by most age groups-was profoundly heightened in neonates and infants, leading to increased incidences of hypotension and cardiac arrest. The neonatal myocardium is immature and is characterized by poor ventricular compliance, poor contractility due to fewer contractile elements, immature sympathetic innervation with decreased norepinephrine stores, and immature mechanisms for storage and exchange of calcium in the sarcoplasmic reticulum. In vitro studies of myocardial contractility of mammalian fetal and adult myocardium demonstrated that the fetal heart was twice as sensitive to halothane as the adult. Clinical studies demonstrated that most neonates and infants less than 6 months of age experienced hypotension during halothane induction of anesthesia and significantly (p < .01) greater decreases in blood pressure than older children at equipotent concentrations of halothane. Intraoperative cardiac arrest during the halothane era occurred over twice as frequently in neonates aged less than 1 month than in infants aged 1-12 months and nearly 10 times more frequently than children 1-5 years of age. Halothane was associated with 66% of intraoperative drug-related cardiac arrests in children. The halothane era began to close in the late 1990s with the introduction of sevoflurane, which had a more favorable hemodynamic profile. Shortly thereafter, halothane was completely displaced from pediatric anesthesia practice in North America.

Pearls and Pitfalls in Pediatric Kidney Transplantation After 5 Decades

Worldwide, over 1,300 pediatric kidney transplantations are performed every year. Since the first transplantation in 1959, healthcare has evolved dramatically. Pre-emptive transplantations with grafts from living donors have become more common. Despite a subsequent improvement in graft survival, there are still challenges to face. This study attempts to summarize how our understanding of pediatric kidney transplantation has developed and improved since its beginnings, whilst also highlighting those areas where future research should concentrate in order to help resolve as yet unanswered questions. Existing literature was compared to our own data of 411 single-center pediatric kidney transplantations between 1968 and 2020, in order to find discrepancies and allow identification of future challenges. Important issues for future care are innovations in immunosuppressive medication, improving medication adherence, careful donor selection with regard to characteristics of both donor and recipient, improvement of surgical techniques and increased attention for lower urinary tract dysfunction and voiding behavior in all patients.

Perioperative anesthesia care for the pediatric patient undergoing a kidney transplantation: An educational review

Living-donor kidney transplantation is the first choice therapy for children with end-stage renal disease and shows good long-term outcome. Etiology of renal failure, co-morbidities, and hemodynamic effects, due to donor-recipient size mismatch, differs significantly from those in adult patients. Despite the complexities related to both patient and surgery, there is a lack of evidence-based anesthesia guidelines for pediatric kidney transplantation. This educational review summarizes the pathophysiological changes to consider and suggests recommendations for perioperative anesthesia care, based on recent research papers.

Intraoperative Cardiac Arrest: Immediate Treatment and Diagnostic Evaluation

Although perioperative cardiac arrest during anesthetic care in infants and children is a rare event, its consequences can be devastating. Risk factors associated with perioperative cardiac arrest include cardiac surgery, younger age, presence of comorbid conditions and emergency surgery. Although medication-related etiologies formerly predominated, the elimination of halothane from anesthetic care has resulted in a shift in etiology to hemodynamic events related to blood loss or hyperkalemia associated with the rapid administration of blood products. Rarely, cardiac arrest can be sudden and unexpected without an obvious pre-existing etiology in an otherwise apparently healthy patient. We present a 16-month-old child who experienced a sudden cardiac arrest following anesthetic induction for a routine urologic procedure. The potential etiology of cardiac arrest during anesthesia is reviewed, keys to resuscitation discussed, and an outline for the investigative work-up presented.

TIVA versus Inhalational Agents for Pediatric Cardiac Intensive Care

The field of pediatric intensive care has come a long way, especially with the recognition that adequate sedation and analgesia form an imperative cornerstone of patient management. With various drugs available for the same, the debate continues as to which is the better: total intravenous anesthesia (TIVA) or inhalational agents. While each have their own advantages and disadvantages, in the present era of balance toward the IV agents, we should not forget the edge our volatile agents (VAs) might have in special scenarios. And ultimately as anesthesiologists, let us not forget that be it knob and dial, or syringe and plunger, our aim is to put pain to sleep and awaken a new faith to breathe.

The predictive value of the Pleth Variability Index on fluid responsiveness in spontaneously breathing anaesthetized children-A prospective observational study

BACKGROUND

In children, the preoperative hydration status is an important part of the overall clinical assessment. The assumed preoperative fluid deficit is often routinely replaced during induction without knowing the child's actual fluid status.

AIM

We investigated the predictive value of the Pleth Variability Index as a measure of fluid responsiveness in spontaneously breathing anesthetized children.

METHODS

Pleth Variability Index, stroke volume and Cardiac Index, measured by electrovelocimetry, mean blood pressure, and heart rate were recorded during anesthesia induction in 50 pediatric patients <6 years. Baseline values were compared to values recorded after administration of 10 mL/kg of Ringer's lactate and during two passive leg raising tests (before and after fluid administration). Fluid responsiveness was defined as an increase of ≥10% in stroke volume.

RESULTS

Only in fluid responsive patients, Pleth Variability Index values were higher before fluid administration than thereafter (21.4 ± 5.9% vs 15.0 ± 9.4%, 95% CI of difference 1.1 to 11.8%, P = .02). Pleth Variability Index values at baseline were higher in fluid responders (21.4 ± 5.9%) than in fluid nonresponders (15.3 ± 7.7%), 95% CI of difference 1.6 to 10.6%, P = .009. The area under the receiver operating curve indicating fluid responsiveness was 0.781 (95% CI 0.623 to 0.896, P = .0002), with the highest sensitivity (82%) and specificity (70%) at a Pleth Variability Index of >15% (Positive predictive value 2.71 (95% CI: 1.4 to 5.2)). Only in fluid responders, the Pleth Variability Index decreased during passive leg raising, while stroke volume increased.

CONCLUSIONS

The Pleth Variability Index may be of additional value to predict fluid responsiveness in spontaneously breathing anesthetized children. A significant overlap in baseline Pleth Variability Index values between fluid responsive and nonfluid responsive patients does not allow a reliable recommendation as to a cut off value.

Cardiac arrest after induction of anesthesia in a 2-month-old infant with undiagnosed Williams syndrome

A 2-month-old male infant presented for elective repair of inguinal hernias. His preoperative medical history and physical examination were unremarkable. During induction of anesthesia, the infant sustained an adverse cardiac event. The event was characterized by tachycardia, hypotension, and massive ST-segment elevation. Despite vigorous resuscitation, spontaneous hemodynamic stability could not be achieved and extracorporeal membrane oxygenation was required. A transthoracic echocardiogram revealed severe hypoplasia of the ascending aorta. As effective cardiac function did not recover and there was evidence of diffuse ischemic brain injury, life support was withdrawn. Genetic testing performed postoperatively was definitive for Williams syndrome.

Comparison of speed of inhalational induction in children with and without congenital heart disease

BACKGROUND

Conduct of stable inhalational anesthetic induction in children with congenital heart disease (CHD) presents special challenges. It requires in-depth understanding of the effect of congenital shunt lesions on the uptake, delivery, and equilibration of anesthetic drugs. Intracardiac shunts can alter the induction time and if delivery of anesthetic agent is not carefully titrated, can lead to overdosing and undesirable myocardial depression.

AIMS

To study the effect of congenital shunt lesions on the speed of inhalational induction and also the impact of inhalational induction on hemodynamics in the presence of congenital shunt lesions.

SETTING

Tertiary care hospital.

DESIGN

A prospective, single-center clinical study.

MATERIALS AND METHODS

Ninety-three pediatric patients undergoing elective surgery were segregated into three equal groups, namely, Group 1: no CHD, Group 2: acyanotic CHD, and Group 3: cyanotic CHD. General anesthesia was induced with 8% sevoflurane in 6 L/min air-oxygen. The time to induction was noted at loss of eyelash reflex and decrease in bispectral index (BIS) value below 60. End-tidal sevoflurane concentration, minimum alveolar concentration, and BIS were recorded at 15 s intervals for the 1 st min followed by 30 s interval for another 1 min during induction. Hemodynamic data were recorded before and after induction.

RESULTS

Patients in Group 3 had significantly prolonged induction time (99 ± 12.3 s; P < 0.001), almost twice that of the patients in other two groups (51 ± 11.3 s in Group 1 and 53 ± 12.0 s in Group 2). Hypotension occurred after induction in Group 1. No other adverse hemodynamic perturbations were observed.

CONCLUSION

The time to inhalational induction of anesthesia is significantly prolonged in patients with right-to-left shunt, compared to patients without CHD or those with left-to-right shunt, in whom it is similar. Sevoflurane is safe and maintains stable hemodynamics in the presence of CHD.

Decline in ventricular function as a result of general anesthesia in pediatric heart transplant recipients

Echocardiography is frequently performed under anesthesia during procedures such as cardiac catheterization with EMB in pediatric HTx recipients. Anesthetic agents may depress ventricular function, resulting in concern for rejection. The aim of this study was to compare ventricular function as measured by echocardiography before and during GA in 17 pediatric HTx recipients. Nearly all markers of ventricular systolic function were significantly decreased under GA, including EF (-4.2% ±1.2, P < .01) and RV FAC (-0.05 ± 0.02, P = .04). Subjects in the first post-transplant year (n = 9) trended toward a more significant decrease in EF vs those beyond the first post-transplant year (n = 8; -6.0% ±1.2 vs -2.1 ± 2.0, P = .1). This information quantifies a decline in biventricular function that should be expected in pediatric HTx recipients while under GA and can assist the transplant clinician in avoiding unnecessary treatment of transient GA-induced ventricular dysfunction.

Landmark papers in pediatric cardiac anesthesia: documenting the history of the specialty

Pediatric cardiac anesthesia has developed over the past eight decades into a specialty delivering complex clinical care and contributing remarkable scientific progress. The history of this development can be traced through journal articles that mark the strides of the specialty. This article discusses journal articles, chosen by the author, that he considers had a significant impact on the practice of pediatric cardiac anesthesia or are of historical interest.

Age-Related Changes of Normal Cerebral and Cardiac Blood Flow in Children and Adults Aged 7 Months to 61 Years

BACKGROUND

Cerebral and cardiac blood flow are important to the pathophysiology and development of cerebro- and cardiovascular diseases. The purpose of this study was to investigate the age dependence of normal cerebral and cardiac hemodynamics in children and adults over a broad range of ages.

METHODS AND RESULTS

Overall, 52 children (aged 0.6-17.2 years) and 30 adults (aged 19.2-60.7 years) without cerebro- and cardiovascular diseases were included in this study. Intracranial 4-dimensional flow and cardiac 2-dimensional phase-contrast magnetic resonance imaging were performed for all participants to measure flow parameters in the major intracranial vessels and aorta. Total cerebral blood flow (TCBF), cardiac and cerebral indexes, brain volume, and global cerebral perfusion (TCBF/brain volume) were evaluated. Flow analysis revealed that TCBF increased significantly from age 7 months to 6 years (P<0.001) and declined thereafter (P<0.001). Both cardiac and cerebral indices declined with age (P<0.001). The ratio of TCBF to ascending aortic flow declined rapidly until age 18 years (P<0.001) and remained relatively stable thereafter. Age-related changes of cerebral vascular peak velocities exhibited a trend similar to TCBF. By comparison, aortic peak velocities maintained relatively high levels in children and declined with age in adults (P<0.001). TCBF significantly correlated with brain volume in adults (P=0.005) and in 2 pediatric subgroups, aged <7 years (P<0.001) and 7 to 18 years (P=0.039).

CONCLUSIONS

Cerebral and cardiac flow parameters are highly associated with age. The findings collectively highlight the importance of age-matched control data for the characterization of intracranial and cardiac hemodynamics.

Do small doses of atropine (<0.1 mg) cause bradycardia in young children?

OBJECTIVE

To determine the heart rate response to atropine (<0.1 mg) in anaesthetised young infants.

DESIGN

Prospective, observational and controlled.

SETTING

Elective surgery.

PATIENTS

Sixty unpremedicated healthy infants less than 15 kg were enrolled. Standard monitoring was applied. Anaesthesia was induced by mask with nitrous oxide (66%) and oxygen (33%) followed by sevoflurane (8%).

INTERVENTIONS

Intravenous (IV) atropine (5 µg/kg) was flushed into a fast flowing IV. The ECG was recorded continuously from 30 s before the atropine until 5 min afterwards.

MAIN OUTCOME MEASURES

The incidence of bradycardia and arrhythmias was determined from the ECGs by a blinded observer.

RESULTS

The median (IQR) age was 6.5 (4-12) months and the mean (95% CI) weight was 8.6 (8.1 to 9.1) kg. The mean (95% CI) dose of atropine was 40.9 (37.3 to 44) µg. Bradycardia did not occur. Two infants developed premature atrial contractions and one developed a premature ventricular contraction. When compared with baseline values, heart rate increased by 7% 30 s after atropine, 14% 1 min after atropine and 25% 5 min after atropine. Twenty-nine infants (48%) experienced tachycardia (>20% above baseline rate) after atropine lasting 222.7 s (range 27.9-286). The change in heart rate 5 min after atropine was inversely related to the baseline heart rate.

CONCLUSIONS

The upper 95% CI for the occurrence of bradycardia in the entire population of infants based on a zero incidence in this study is 5%. These results rebut the notion that atropine <0.1 mg IV causes bradycardia in young infants.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov #NCT01819064.

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.

Impact of sevoflurane anesthesia on brain oxygenation in children younger than 2 years

OBJECTIVE/AIM

To assess the impact of sevoflurane and anesthesia-induced hypotension on brain oxygenation in children younger than 2 years.

BACKGROUND

Inhalational induction with sevoflurane is the most commonly used technique in young children. However, the effect of sevoflurane on cerebral perfusion has been only studied in adults and children older than 1 year. The purpose of this study was to assess the impact of sevoflurane anesthesia on brain oxygenation in neonates and infants, using near-infrared spectroscopy.

METHODS

Children younger than 2 years, ASA I or II, scheduled for abdominal or orthopedic surgery were included. Induction of anesthesia was started by sevoflurane 6% and maintained with an expired fraction of sevoflurane 3%. Mechanical ventilation was adjusted to maintain an endtidal CO2 around 39 mmHg. Brain oxygenation was assessed measuring regional cerebral saturation of oxygen (rSO2 c), measured by NIRS while awake and 15 min after induction, under anesthesia. Mean arterial pressure (MAP) variation was recorded.

RESULTS

Hundred and ninety-five children were included. Anesthesia induced a significant decrease in MAP (-27%). rSO2 c increased significantly after induction (+18%). Using children age for subgroup analysis, we found that despite MAP reduction, rSO2 c increase was significant but smaller in children ≤ 6 months than in children >6 months (≤ 6 months: rSO2 c = +13%, >6 months: rSO2 c = +22%; P < 0.0001). Interindividual comparison showed that, during anesthesia at steady-state with comparable CMRO2, rSO2 c values were significantly higher when MAP was above 36 mmHg. And the higher the absolute MAP value during anesthesia was, the higher the rSO2 c was. We observed a rSO2 c variation ≤ 0 in 21 patients among the 195 studied, and the majority of these patients were younger than 6 months (n = 19). No increase or decrease of rSO2 c during anesthesia despite reduction of CMRO2 can be explained by a reduction of oxygen supply. Using the ROC curves, we determined that the threshold value of MAP under anesthesia, associated with rSO2 c variation ≤ 0%, was 39 mmHg in all the studied population (AUC: 0.90 ± 0.02; P < 0.001). In children younger than 6 months, this value of MAP was 33 mmHg, and 43 mmHg in children older than 6 months.

CONCLUSION

Despite a significant decrease of MAP, 1 MAC of sevoflurane induced a significant increase in regional brain oxygenation. But subgroup analysis showed that MAP decrease had a greater impact on brain oxygenation, in children younger than 6 months. According to our results, MAP value during anesthesia should not go under 33 mmHg in children ≤6 months and 43 mmHg in children >6 months, as further changes in MAP, PaCO2 or hemoglobin during anesthesia may be poorly tolerated by the brain.

Effects of anesthetics, sedatives, and opioids on ventilatory control

This article provides a comprehensive, up to date summary of the effects of volatile, gaseous, and intravenous anesthetics and opioid agonists on ventilatory control. Emphasis is placed on data from human studies. Further mechanistic insights are provided by in vivo and in vitro data from other mammalian species. The focus is on the effects of clinically relevant agonist concentrations and studies using pharmacological, that is, supraclinical agonist concentrations are de-emphasized or excluded.

[Anesthesia-related cardiac arrest in children. Data from a tertiary referral hospital registry]

OBJECTIVES

The aim of this study is to analyze the cardiac arrests related to anesthesia in a tertiary children's hospital, in order to identify risk factors that would lead to opportunities for improvement.

METHODS

A 5-year retrospective study was conducted on anesthesia related cardiac arrest occurring in pediatric patients. All urgent and elective anesthetic procedures performed by anesthesiologists were included. Data collected included patient characteristics, the procedure, the probable cause, and outcome of the cardiac arrest. Odds ratio was calculated by univariate analysis to determine the clinical factors associated with cardiac arrest and mortality.

RESULTS

There were a total of 15 cardiac arrests related to anesthesia in 43,391 anesthetic procedures (3.4 per 10,000), with an incidence in children with ASA I-II versus ASA≥III of 0.28 and 19.27 per 10,000, respectively. The main risk factors were children ASA≥III (P<.001), less than one month old (P<.001), less than one year old (P<.001), emergency procedures (P<.01), cardiac procedures (P<.001) and procedures performed in the catheterization laboratory (P<.05). The main causes of cardiac arrest were cardiovascular (53.3%), mainly due to hypovolemia, and cardiovascular depression associated with induction of anesthesia, followed by respiratory causes (20%), and medication causes (20%). The incidence of mortality and neurological injury within the first 24h after the cardiac arrest was 0.92 and 1.38 per 10,000, respectively. The mortality in the first 3 months was 1.6 per 10,000. The main causes of death were ASA≥III, age under one year, pulmonary arterial hypertension, cardiac arrest in areas remote from the surgery area, a duration of cardiopulmonary resuscitation over 20min, and when hypothermia was not applied after cardiac arrest.

CONCLUSION

The main risk factors for cardiac arrest were ASA≥III, age under one year, emergency procedures, cardiology procedures and procedures performed in the catheterization laboratory. The main cause of the cardiac arrest was due mainly to cardiovascular hypovolemia. All patients who died or had neurological injury were ASA≥III. Pulmonary arterial hypertension is a risk of anesthesia-related mortality.

Improved outcomes in paediatric anaesthesia: contributing factors

PURPOSE

To discuss developments in paediatric anaesthesia and explore the factors which have contributed to improved anaesthetic-related patient outcomes.

METHODS

Narrative review of findings in the literature retrieved from MEDLINE/Pubmed and manual search.

RESULTS

Adverse perioperative outcomes related to anaesthesia have been extensively debated over the past few decades, with studies implicating factors such as major human error and equipment failure. Case series and event registries have enlightened physicians on sources of error and patient risk factors such as extremes of age, comorbidity and emergent circumstances. Anaesthetic-related deaths in children fell from 6.4 per 10,000 anaesthetics in the early 1950s to as low as 0.1 per 10,000 anaesthetics by the end of the century. Advances in anaesthetic agents, techniques, monitoring technologies and training programmes in paediatric anaesthesia play a vital role in driving this downward trend.

CONCLUSION

Despite substantial progress, there is still much room for improvement in areas such as adverse-event reporting, anaesthetic-related risk and late neurocognitive outcomes. Systematic reviews comparing paediatric patient outcomes after neuroaxial block versus general anaesthesia are currently unavailable. The future of paediatric anaesthesia will most likely be influenced by much-needed large prospective studies, which can provide further insight into patient safety and service delivery.

Recent advances in pediatric anesthesia

Writing about advances in a field of medicine normally includes some pride about progress which one was witness to or even a participant in. The younger one is, the more enthusiastically every advance is lauded and welcomed. This is human nature and nothing to be complained about. However, when anesthesiologists, having worked and struggled in the field of pediatric anesthesia for about 40 years, look back to past advances, a more realistic, even painful picture comes to mind. There was a price which a considerable number of patients had to pay for progress, ruined health or even death. This experience of decades of practice is rarely presented in the literature but should not be forgotten when we proudly remember advances in pediatric anesthesia.

Cardiac arrest in anesthetized children: recent advances and challenges for the future

Over the past 50 years the incidence of anesthesia-related cardiac arrest has declined, despite increased patient co-morbidities, the most significant determinant of anesthetic risk. Multiple factors have contributed to this improvement including safer anesthetic agents, better monitoring devices and the development of a specialized pediatric environment. Provider skill has benefitted from improved training and recognition of high-risk situations. Further improvements will depend on international, multispecialty efforts to standardize terminology and analyze large numbers of these infrequent adverse events.

Efficacy of different concentrations of sevoflurane administered through a face mask for magnetic resonance imaging in children

BACKGROUND

The main aim of this study was to use a non-invasive method such as a face mask to maintain anesthesia in children during magnetic resonance imaging (MRI). The secondary aim was to ascertain hemodynamic-respiration parameters, recovery time and complications of anesthesia with the administration of different concentrations of sevoflurane.

METHODS

This prospective and randomized study included 96 ASA I-II children, aged 1-10, scheduled to undergo MRI with anesthesia with sevoflurane through a face mask. All patients were administered midazolam 0.5 mg·kg(-1) orally 30 min before anesthesia induction. Sevoflurane 8% was given to induce anesthesia under assisted-controlled ventilation for 2 min, and an intravenous route was opened on the hand. Three different concentrations of sevoflurane were administered through a face mask under spontaneous respiration to maintain anesthesia. A mixture of sevoflurane, oxygen, and air of 5 l·min(-1) was given through a face mask for anesthesia. Group 1 (n = 32) received 1.5% sevoflurane, Group 2 (n = 32) 1.25% sevoflurane, and Group 3 (n = 32) 1.0% sevoflurane. Recovery time, removal from the MRI room, postanesthesia care unit discharge data, and complications were also recorded. Heart rate, mean arterial pressure (MAP), peripheral oxygen saturation (SpO(2)), respiration rate, and anesthesia adequacy were recorded every 5 min from the time of induction until completion of the MRI.

RESULTS

All three groups were similar in demographic and hemodynamic respiratory features. MRI was successfully performed in 96.6% of all patients without additional intervention. Sevoflurane concentrations were increased for a short time in one patient in Group 1 and in two patients in Group 3. Oxygen flow was increased in one patient in Group 1 and in one patient in Group 2 as SpO(2) was lower than 95%. The mean time to eye opening (from discontinuation of sevoflurane to eye opening) was 155.8 ± 50.0 s in Group 1, 89.5 ± 16.0 s in Group 2, and 53.5 ± 10.0 s in Group 3; differences between the groups were statistically significant (P = 0.001). Airways were not used on any of the patients, and none vomited or required endotracheal intubation or laryngeal mask anesthesia.

CONCLUSIONS

We believe that the administration of sevoflurane at a concentration of 1% via a face mask under spontaneous respiration may provide light anesthesia without complications to induce an unarousable sleep for children during MRI.

Minimum alveolar concentrations and hemodynamic effects of two different preparations of sevoflurane in pigs

BACKGROUND

Original sevoflurane (Sevo A) is made with water, while a generic sevoflurane (Sevocris) is produced with propylene glycol as a stabilizing additive. We investigated whether the original and generic sevoflurane preparations differed in terms of their minimum alveolar concentration (MAC) values and hemodynamic effects.

METHODS

Sixteen pigs weighing 31.6+/-1.8 kg were randomly assigned to the Sevo A or Sevocris groups. After anesthesia induction via mask with the appropriate sevoflurane preparation (6% in 100% oxygen), the MAC was determined for each animal. Hemodynamic and oxygenation parameters were measured at 0.5 MAC, 1 MAC and 1.5 MAC. Histopathological analyses of lung parenchyma were performed.

RESULTS

The MAC in the Sevo A group was 4.4+/-0.5%, and the MAC in the Sevocris group was 4.1+/-0.7%. Hemodynamic and metabolic parameters presented significant differences in a dose-dependent pattern as expected, but they did not differ between groups. Cardiac indices and arterial pressures decreased in both groups when the sevoflurane concentration increased from 0.5 to 1 and 1.5 MAC. The oxygen delivery index (DO(2)I) decreased significantly at 1.5 MAC.

CONCLUSION

Propylene glycol as an additive for sevoflurane seems to be as safe as a water additive, at least in terms of hemodynamic and pulmonary effects.

Anaesthetic complications associated with the treatment of patients with congenital cardiac disease: consensus definitions from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease

Congenital heart defects are the most common cause of death in infants and young children in the developed world. As the mortality in this population has declined to less than 5%, more attention is being focused now on reducing post-procedural morbidities that may seriously impact the patient and their families. Because of multiple reasons, paediatric cardiac surgery and anaesthesia is a perfect model for studying human errors and their impact on patient safety. Congenital cardiac disease is a common lesion causing much morbidity, pain, and loss of life. Over 44,000 surgical procedures are performed yearly to repair congenital cardiac problems in the United States alone. The reduction or elimination of iatrogenic adverse outcomes, given the current mortality rates of 4.2%-4.5%, might lead to as many as 500 children achieving better outcomes or shorter hospitalizations.Efforts to quantify the frequency of complications related to anaesthesia in patients undergoing congenital cardiac surgery have been difficult to date because of the low occurrence of this surgery compared to other surgeries on children and the relatively rare incidence of complications related to anaesthesia in this population. Anaesthesiologists play a crucial role in the reduction, recognition, and timely treatment of medical errors that impact this morbidity. Paediatric cardiac surgery encompasses many complex procedures that are highly dependent upon a sophisticated organizational structure, effective communication, coordinated efforts of multiple individuals working as a team, and high levels of cognitive and technical performance. Human factor error analysis in this patient population has shown how frequently both minor and major errors occur. The goal of this paper is to outline the frequency and sources of these errors and to suggest treatment strategies which may minimize their occurrence.

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.

Comparison of the cardiovascular effects of isoflurane and sevoflurane as measured by magnetic resonance imaging in children with congenital heart disease

STUDY OBJECTIVE

To compare the cardiovascular effects of isoflurane and sevoflurane at minimum alveolar concentration (MAC) = 1 in children with congenital heart disease using cardiac magnetic resonance imaging.

DESIGN

Randomized, crossover, single-blinded study.

SETTING

Tertiary-care teaching hospital.

PATIENTS

10 pediatric patients with congenital heart diseases scheduled to undergo cardiac magnetic resonance studies.

INTERVENTIONS

Patients were randomized to receive either isoflurane or sevoflurane as the "first inhalation agent." After a period or more than 20 minutes, they were crossed over to receive the "second inhalation agent."

MEASUREMENTS

Heart rate, mean arterial pressure (MAP), cardiac index, stroke volume index, and ejection fraction (EF) at one MAC for both agents were all recorded.

MAIN RESULTS

Both isoflurane and sevoflurane caused a significant decrease in MAP from the baseline (P = 0.013). The mean values (+/-SD) of stroke volume (mL), cardiac index (L min(-1) m(-2)), and EF (%) for isoflurane versus sevoflurane were 21.5 (+/-9.2) versus 19.6 (+/-6.2), 4.1 (+/-1.2) versus 3.7 (+/-0.87), and 64.2 (+/-14.5) versus 62.5 (+/-13.8), respectively.

CONCLUSION

Both isoflurane and sevoflurane were found to be comparable in terms of cardiovascular effects.

Effect of propofol on emergence behavior in children after sevoflurane general anesthesia

BACKGROUND

Emergence agitation (EA) is a postoperative behavior that may occur in children undergoing general anesthesia with inhaled agents.

OBJECTIVES

The aim of the present study was to assess the effect of propofol administered at the end of sevoflurane anesthesia on the incidence and severity of EA in children undergoing magnetic resonance imaging (MRI).

METHODS

Eighty-four children, 2-7 years old, undergoing MRI were enrolled in this randomized double-blind study. No sedative premedication was administered prior to anesthesia induction. Anesthesia was induced and maintained with sevoflurane in N(2)O/O(2). Group P received propofol 1 mg.kg(-1) and group S received saline. Pediatric Anesthesia Emergence Delirium scale (PAEDs) was used to evaluate recovery characteristics upon awakening and during the first 30 min after emergence from anesthesia. Children with PAEDs >16 were considered agitated. EA was analyzed using the Mann-Whitney U-test. Demographic data and other side effects were analyzed using the Student's t-test.

RESULTS

Eighty-three children completed the study. There were 42 children in group P. EA was diagnosed in two children in the propofol group (4.8%) and in 11 children in the placebo group (26.8%, P < 0.05). Time to achieving postanesthesia care unit discharge criteria was not different between the two groups.

CONCLUSIONS

The addition of propofol 1 mg.kg(-1) can significantly decrease the incidence of EA after sevoflurane general anesthesia in children undergoing nonpainful procedures.

Ketamine is effective in decreasing the incidence of emergence agitation in children undergoing dental repair under sevoflurane general anesthesia

BACKGROUND

Emergence agitation or delirium is a known phenomenon that may occur in children undergoing general anesthesia with inhaled agents. Our aim was to test the hypothesis that the addition of a small dose of ketamine at the end of sevoflurane anesthesia will result in a decrease in the incidence and severity of such phenomenon.

METHODS

We performed a randomized double blind study involving 85 premedicated children 4-7 years old undergoing dental repair. Children were premedicated with acetaminophen and midazolam. Anesthesia was induced and maintained with sevoflurane in N2O/O2. Group K received ketamine 0.25 mg.kg (-1) and Group S received saline. We evaluated recovery characteristics upon awakening and during the first 30 min using the Pediatric Anesthesia Emergence Delirium scale.

RESULTS

Eighty of the 85 enrolled children completed the study. There were 42 children in Group I. Emergence agitation was diagnosed in seven children in the ketamine group (16.6%) and in 13 children in the placebo group (34.2%). There was no difference in time to meet recovery room discharge criteria between the two groups.

CONCLUSIONS

We conclude that the addition of ketamine 0.25 mg.kg(-1) can decrease the incidence of emergence agitation in children after sevoflurane general anesthesia.

Anesthesia-Related Cardiac Arrest in Children: Update from the Pediatric Perioperative Cardiac Arrest Registry

BACKGROUND

The initial findings from the Pediatric Perioperative Cardiac Arrest (POCA) Registry (1994-1997) revealed that medication-related causes, often cardiovascular depression from halothane, were the most common. Changes in pediatric anesthesia practice may have altered the causes of cardiac arrest in anesthetized children.

METHODS

Nearly 80 North American institutions that provide anesthesia for children voluntarily enrolled in the Pediatric Perioperative Cardiac Arrest Registry. A standardized data form for each perioperative cardiac arrest in children </=18 yr of age was submitted anonymously. We analyzed causes of anesthesia-related cardiac arrests and related factors in 1998-2004.

RESULTS

From 1998 to 2004, 193 arrests (49%) were related to anesthesia. Medication-related arrests accounted for 18% of all arrests, compared with 37% from 1994 to 1997 (P < 0.05). Cardiovascular causes of cardiac arrest were the most common (41% of all arrests), with hypovolemia from blood loss and hyperkalemia from transfusion of stored blood the most common identifiable cardiovascular causes. Among respiratory causes of arrest (27%), airway obstruction from laryngospasm was the most common cause. Vascular injury incurred during placement of central venous catheters was the most common equipment-related cause of arrest. The cause of arrest varied by phase of anesthesia care (P < 0.01). Cardiovascular and respiratory causes occurred most commonly in the surgical and postsurgical phases, respectively.

CONCLUSIONS

A reduction in the proportion of arrests related to cardiovascular depression due to halothane may be related to the declining use of halothane in pediatric anesthetic practice. The incidence of the most common remaining causes of arrest in each category may be reduced through preventive measures.

Cardiac rhythm and left ventricular function of infants at 1 MAC sevoflurane and halothane

BACKGROUND

The implementation of sevoflurane in pediatric anesthesia practice led to a decrease in the incidence of cardiac arrest previously reported with halothane. Nevertheless, the effects of sevoflurane on cardiac rhythm and function have not been systematically investigated in infants. Thus, we compared cardiac rhythm and left ventricular function at 1 MAC sevoflurane and halothane anesthesia and investigated the potential benefit effect of atropine.

METHODS

Twenty infants ASA physical status I or II were randomly assigned to have anesthesia induced with either sevoflurane (up to 5%) or halothane (up to 1.5%). After insertion of an i.v. line, anesthesia was maintained at 1 MAC sevoflurane (group S) or 1 MAC halothane (group H) with infants breathing spontaneously in 100% oxygen. Cardiac output and contractility were measured by transthoracic echocardiography. Three sets of hemodynamic parameters were averaged prior to and after administration of 20 microg x kg(-1) of i.v. atropine.

RESULTS

Infants breathing spontaneously 1 MAC halothane or 1 MAC sevoflurane were found to have comparable hemodynamic parameters. After atropine administration, heart rate and cardiac index (CI) increased significantly in both groups (19.6 +/- 7.6% in group H and 21.3 +/- 13.1% in group S, 18.6 +/- 8.8% in group H and 17.7 +/- 12% in group S respectively). Moreover, atropine induced an increase in left ventricular shortening fraction with no difference between groups. In contrast, only infants in group S presented a significant increase in ejection fraction.

CONCLUSIONS

Indices of left ventricular function were comparable between groups with no clinically significant change following atropine administration. The present study confirms the favorable hemodynamic profile of sevoflurane in infants breathing spontaneously at 1 MAC concentration.

Pharmacokinetic/pharmacodynamic modeling of anesthetics in children: therapeutic implications

Modeling the pharmacokinetics and pharmacodynamics of anesthetics in children is performed as a response to the clinical need for safe and efficacious administration of drugs with a low therapeutic index. Rates and concentrations of these drugs, which are the primary parameters used by anesthesiologists, depend on physiologic parameters that are markedly affected by development. Volatile anesthetics have been used for >50 years in pediatric patients. The pharmacokinetics of inhalation agents are context sensitive, but little difference between age groups has been described. These agents are not only eliminated unchanged by the lung but they are also metabolized by the liver. Halothane has Michaelis-Menten kinetics, with up to 40% of the administered dose metabolized by the liver. For volatile anesthetics, the effect measured is the minimum alveolar concentration (MAC) that leads to movement of the limb in response to skin incision in 50% of the patients studied. The MAC is higher in infants than in children and adults. Infants aged 6 months have a MAC 1.5-1.8 times the MAC observed in adults aged 40 years. Children have a greater clearance and volume of distribution of propofol than adults. In order to achieve similar plasma concentrations, children require three times the initial dose used in adults. In adults, an increased sensitivity to propofol has been demonstrated with aging, but nothing is known about the effects in children. However, it is clear that equipotent doses of propofol induce marked deleterious hemodynamic effects in infants compared with children. Regional anesthesia is used in pediatrics, both in combination with general anesthesia during surgery or alone for postoperative analgesia. A marked decrease in protein binding has been described in infants. In the postoperative period, a rapid increase in binding because of inflammation decreases the free fraction, but the free drug concentration remains constant because of the resulting decrease in total clearance. A low clearance because of liver function immaturity has been observed during the first year(s) of life for bupivacaine and ropivacaine. Pharmacodynamic interactions between general anesthesia and regional anesthesia need to be modeled. This is one of the future tasks for pharmacokineticists. Methods such as the Dixon up-and-down allocation and the isobolographic technique are promising in this field.

An Update on Pediatric Anesthesia Liability: A Closed Claims Analysis

BACKGROUND

Respiratory complications were associated with half of pediatric malpractice claims from the 1970s to 1980s in the ASA Closed Claims Database. Advances in pediatric anesthesia practice have occurred in the 1980s and 1990s and may be reflected in liability trends.

METHODS

We reviewed 532 pediatric (age < or =16 yr) malpractice claims from our database over three decades (1973-2000), using logistic regression analysis to evaluate trends over time. Claims from 1990 to 2000 (1990s) were reviewed in detail to determine damaging events and injuries. Multiple logistic regression analysis evaluated factors associated with claims for death/brain damage (BD) compared with claims for less severe injuries.

RESULTS

From 1973 to 2000, there was a decrease in the proportion of claims for death/BD (P = 0.002) and respiratory events (P < 0.001), particularly for inadequate ventilation/oxygenation (P < 0.001). However, claims for death (41%) and BD (21%) remained the dominant injuries in pediatric anesthesia claims in the 1990s. Half of the claims in 1990-2000 involved patients 3 yr or younger and one-fifth were ASA 3-5. Cardiovascular (26%) and respiratory (23%) events were the most common damaging events. Factors associated with claims for death/BD in the 1990s when compared with claims for less severe injuries were cardiovascular events (odds ratio [OR] = 6.6, 95% confidence interval [CI] = 2.5-17.8), respiratory events (OR = 3.7, 95% CI = 1.5-9.4), and ASA status 3-5 (OR = 3.1, 95% CI = 1.3-7.8).

CONCLUSIONS

Death/BD remained the dominant injuries in pediatric anesthesia malpractice claims in the 1990s. Cardiovascular events joined respiratory events as the major sources of liability.

Anesthetic management of a young adult with complex congenital heart disease and bronchopleural fistula for rigid bronchoscopy

The number of adults with congenital heart disease and those who require anesthetic care are increasing. We describe the anesthetic management of a young adult with palliated complex congenital heart disease and a chronic postsurgical bronchopleural fistula for rigid bronchoscopy. Perioperative considerations in the care of patients with single ventricle physiology for noncardiac procedures are reviewed. Specific requirements for rigid bronchoscopy are discussed in addition to the anesthetic implications of a bronchopleural fistula and particular concerns in the patient with single ventricle physiology.

Office-based anaesthesia

Office-based anaesthesia is a young but rapidly growing speciality practice. In patient selection, surgical procedures, and anaesthetic techniques this practice is similar to standard ambulatory surgery; however, the liability and risks of office-based anaesthesia are greater. The anaesthesiologist's major challenge is to insist on patient safety in this developing field.

Anästhesiologische Aspekte in der Neu- und Frühgeborenenchirurgie

The physiology of the preterm and term neonate is characterized by a high metabolic rate, limited pulmonary, cardiac and thermoregulatory reserve and decreased renal function. Multisystem immaturity creates important developmental differences in drug administration and response when compared to older children. Specific monitoring techniques are required because the neonate is not physically accessible to the anesthetist during the operation. This contribution reviews the specific pathophysiological characteristics of the newborn with relevance to anesthesia and also provides robust guidelines for the anesthetic management of the most frequent non-cardiac procedures which need surgery during the neonatal period. Consideration will also be given to the anesthetic management of very low birth-weight infants with anesthetic key issues such as avoiding hyperoxia, keeping hemodynamic parameters as stable as possible and preventing hypothermia.

Modern fasting guidelines in children

Pediatric fasting guidelines are intended to reduce the risk of pulmonary aspiration of gastric contents and facilitate the safe and efficient conduct of anesthesia. Recent changes in these guidelines, while assuring appropriate levels of patient safety, have been directed at improving the overall perioperative experience for infants, children, and their parents. Now after nearly 15 years of practice worldwide, the relative safety and benefits of allowing clear liquids up to 2 hr prior to anesthesia for otherwise healthy children are well established. Shortened fasting periods for breast milk (3 hr), formula (4 hr) and light meals (6 hr) are supported by accumulated experience and an evolving literature that includes evidence of minimal gastric fluid volumes (GFVs) at the time of surgery. Ideal fasting intervals for children with disorders that may affect gastrointestinal transit have yet to be determined.

Perioperative cardiac arrest and its mortality in children. A 9-year survey in a Brazilian tertiary teaching hospital

BACKGROUND

The incidence of perioperative cardiac arrest and mortality in children is higher than in adults. This survey evaluated the incidence, causes, and outcome of perioperative cardiac arrests in a pediatric surgical population in a tertiary teaching hospital between 1996 and 2004.

METHODS

The incidence of cardiac arrest during anesthesia was identified from an anesthesia database. During the study period, 15,253 anesthetics were performed in children. Data collected included patient demographics, surgical procedures (elective, urgent, or emergency), ASA physical status classification, anesthesia provider information, type of surgery, surgical areas, and outcome. All cardiac arrests were reviewed and grouped by the cause of arrest and death into one of four groups: totally anesthesia-related, partially anesthesia-related, totally surgery-related, or totally child disease or condition-related.

RESULTS

There were 35 cardiac arrests (22.9 : 10,000) and 15 deaths (9.8 : 10,000). Major risk factors for cardiac arrest were neonates and children under 1 year of age (P < 0.05) with ASA III or poorer physical status (P < 0.05), in emergency surgery (P < 0.05), and general anesthesia (P < 0.05). Child disease/condition was the major cause of cardiac arrest or death (P < 0.05). There were seven cardiac arrests because of anesthesia (4.58 : 10,000)--four totally (2.62 : 10,000) and three partially related to anesthesia (1.96 : 10,000). There were no anesthesia attributable deaths reported. The main causes of anesthesia attributable cardiac arrest were respiratory events (71.5%) and medication-related events (28.5%).

CONCLUSIONS

Perioperative cardiac arrests were relatively higher in neonates and infants than in older children with severe underlying disease and during emergency surgery. The fact that all anesthesia attributable cardiac arrests were related to airway management and medication administration is important in prevention strategies.

Inhalation induction using sevoflurane in children: the single-breath vital capacity technique compared to the tidal volume technique*

The single-breath vital capacity technique is suitable for inhalation induction of anaesthesia, using sevoflurane in children aged > 5 years. The purpose of this randomised trial was to compare the single breath vital capacity technique with the conventional tidal volume technique. Seventy- three ASA 1 or 2 children were instructed during the pre-operative visit in the vital capacity technique. The main criterion measured was time to loss of the eyelash reflex. Induction was performed using a circle-absorber breathing circuit primed with sevoflurane 7% in 50% nitrous oxide/oxygen with 6 l.min(-1) fresh gas flow. Time required for induction, haemodynamic changes, airway tolerance and side-effects were recorded. The children's opinion on the technique used was scored using a visual analogue scale (0-100) and a Smiley scale (0-10). The time to loss of the eyelash reflex was found to be reduced in the vital capacity group compared to the tidal volume group. The time to central myosis, to achieve bispectral index values 60 and 40, haemodynamic changes, respiratory events and side-effect incidences were similar in both groups. However, we found that the vital capacity technique was preferred by the children to the tidal volume technique.

Paediatric anaesthesia and inhalation agents

Inhalation agents are amongst the mainstays of paediatric anaesthesia, as children are often induced by mask before venous access is obtained. Children do not like needles and obtaining venous access in an awake and moving child can be very demanding. Safety aspects are of particular importance in paediatric anaesthesia. Therefore, the possibility of monitoring end-tidal concentrations facilitates correct dosing in all patients, from the preterm infant weighing less than 1000 g to the adult-sized adolescent. For induction, sevoflurane has nearly universally replaced halothane, leading to increased cardiovascular safety. The main disadvantages of inhalation agents, especially sevoflurane and desflurane, are delirious behaviour and agitated states during emergence. In addition, there remains uncertainty regarding the relevance of the cerebral stimulating pattern of some of these agents. Inhalation anaesthesia has a long tradition, whereas the experience with propofol is comparatively small. The incidence and clinical relevance of the propofol infusion syndrome during clinical anaesthesia are still unknown. Inhalation anaesthesia is still considered to be the gold standard by the overwhelming majority of paediatric anaesthetists world-wide, however, intravenous techniques can be an attractive alternative in specific clinical situations.

[Anesthetic management of pediatric cleft lip and cleft palate repair]

We have developed a modern strategy for the anesthetic management of pediatric cleft lip and cleft palate repair using anesthetic drugs such as sevoflurane, desflurane, acetaminophen, remifentanil, and pirtitramide together with new techniques. It provides best conditions for the surgeon and maximum safety for the pediatric patient. A team of pediatricians, neonatologists, pediatric surgeons, and pediatric anesthetists have tackled the problem of management of children with craniofacial abnormalities such as cleft lip and cleft palate. The best and safest anesthetic techniques are outlined and the most frequent complications are discussed, e.g. management of the difficult airway, the airway in patients with complex craniofacial abnormalities, fiberoptic endotracheal intubation through a laryngeal mask, intraoperative dislocation of the endotracheal tube, postoperative airway obstruction and perioperative bleeding.

Sevoflurane (12% and 8%) inhalational induction in children

BACKGROUND

Sevoflurane induction of anesthesia is frequently used in children. Rapidly performed inhalational induction may reduce excitation during early anesthesia. Increasing the total anesthetic MAC delivered to patients can be achieved by increasing volatile concentration or adding nitrous oxide. The latter reduces inspired oxygen concentration delivered, which may not be desirable. Even 8% sevoflurane induction is associated with excitation. A system capable of delivering 12% sevoflurane using two tandem vaporizers has been developed.

METHODS

A randomized double blind study was undertaken to assess whether 12% sevoflurane offered any advantage over 8% in time and quality of induction. Sixty children aged 5-10 years were recruited and received either 12 or 8% sevoflurane. Time to loss of eyelash reflex, central pupils, incidence of adverse events, induction quality, systolic blood pressure and heart rate were recorded.

RESULTS

Twelve percent sevoflurane reduced time to loss of eyelash reflex compared with 8% [mean (sd): 35 (12) and 46 (14) P<0.05], but the reduction was only 10% higher than the error in the measurement (assessment every 10 s). Twelve percent sevoflurane offered significantly better quality of induction (P<0.05). There was no difference in cardiovascular stability between groups, although heart rate rose significantly in both groups. Maintaining sevoflurane at 12% for 4 min caused significant amounts of apnea (69% with 12% and 38% with 8%, P<0.05).

CONCLUSION

Twelve percent sevoflurane offers a smoother anesthesia induction than 8% in children of this age with no additional consequences for the cardiovascular system.