Hybrid pulmonary artery plication followed by transcatheter pulmonary valve replacement: Comparison with surgical PVR.

Objective/Background Historically, the sole option for patients with a dysfunctional native right ventricular outflow tract (RVOT) requiring re-establishment of pulmonary competence has been surgical PVR. We sought to compare early outcomes of hybrid pulmonary valve replacement (PVR) combining surgical plication of the main pulmonary artery followed by transcatheter PVR, with a contemporary cohort of surgical PVR patients. Methods Retrospective chart analysis of all patients with a dilated native RVOT eligible for surgical PVR over 36 months was performed. The cohorts included patients with previous tetralogy of Fallot repair (n = 14), and previous intervention for congenital abnormality of the pulmonary valve (n = 7). Results Twenty-one patients with a dysfunctional native RVOT met criteria for PVR; 8 using the hybrid procedure (group 1: age, 31.5 +/- 17.4 years) and 13 with cardiopulmonary bypass (CPB) (group 2: age, 31 +/- 18.4 years). Valve delivery was successful in all patients with no procedural mortality. Group 1 had a lesser requirement for blood products (P =< 0.001) and a trend toward shorter hospital stay and higher post-operative hemoglobin. No patients in group 1 received inotropic support post-operatively compared to 54% of patients in group 2. Mean follow-up was 3.4 months for group 1 and 13.6 months for group 2 with the average peak gradient across the RVOT of 20.1 and 15.1 mm Hg respectively (P = 0.12), all with no more than mild PI. Conclusions Transcatheter hybrid PVR following RVOT plication provides a reasonable alternative to surgical PVR particularly in higher risk cohorts, reducing possible longer-term consequences of repeated runs of CPB. © 2016 Wiley Periodicals, Inc.

Anomalous Left Coronary From the Pulmonary Artery Presenting as Ventricular Fibrillation After Persistent Ductus Arteriosus Ligation.

An anomalous left coronary artery from the pulmonary artery (ALCAPA) is rarely associated with persistent ductus arteriosus (PDA). A large PDA can maintain perfusion in the left coronary artery, delaying presentation. Assessing the origin of the coronary arteries before PDA ligation is difficult, often being performed in very small or even preterm babies. We present the case of a 5-month-old infant with echocardiographic features of mitral regurgitation and subendocardial ischemia who experienced ischemia and cardiac arrest after PDA ligation. Transesophageal echocardiography demonstrated ALCAPA, and left coronary translocation was performed. The infant was discharged after 10 days.

Limitations and vulnerabilities of the neonatal cardiovascular system: considerations for anesthetic management.

Development of the cardiovascular system through the last trimester of pregnancy and the subsequent neonatal period is profound. Morphological changes within the myocardium make the heart vulnerable to challenges such as fluid shifts and anesthetic drugs. The sensitivity of the myocardium to metabolic challenges and potential harm of drugs needed to maintain adequate blood pressure and cardiac output are highlighted. Traditional monitoring under anesthesia has focussed on maintaining oxygenation and heart rate in the neonate with less attention paid to blood pressure, cardiac output, and more importantly organ well-being. There is now a better understanding of the limitations of blood pressure homeostasis in the neonate and the potential consequences of marginal hypoperfusion. This article highlights some of these vulnerabilities particularly as they relate to anesthesia and surgery in the very young.

Ductal ligation in the very low-birth weight infant: simple anesthesia or extreme art?

Management of the very low-birth weight infant in the neonatal intensive care unit (NICU) is geared to provide optimal outcome not only in term of survival but increasingly with a goal of limitation of long-term neurological and pulmonary morbidities. Careful follow-up studies have demonstrated that relatively small variations in oxygenation and gas exchange, ventilator management, and other management modalities can have long-term consequences. Within this context, there are good data that closure of a clinically significant patent ductus arteriosus has outcome benefit, but little data on the idealized anesthetic to manage such fragile patients. Does the anesthetic management matter? Given the attention to detail within the NICU, it would seem prudent to try to choose techniques that limit changes in hemodynamics, gas exchange, and ventilation within the context of the surgery. Anesthesia for ductal ligation in the very low-birth weight infant may need to be judged by more than simple survival and brings into question the current techniques and monitoring used.

Effects of regional analgesia on stress responses to pediatric surgery.

Invasive surgery induces a combination of local response to tissue injury and generalized activation of systemic metabolic and hormonal pathways via afferent nerve pathways and the central nervous system. The local inflammatory responses and the parallel neurohumoral responses are not isolated but linked through complex signaling networks, some of which remain poorly understood. The magnitude of the response is broadly related to the site of injury (greater in regions with visceral pain afferents such as abdomen and thorax) and the extent of the trauma. The changes include alterations in metabolic, hormonal, inflammatory, and immune systems that can be collectively termed the stress response. Integral to the stress responses are the effects of nociceptive afferent stimuli on systemic and pulmonary vascular resistance, heart rate, and blood pressure, which are a combination of efferent autonomic response and catecholamine release via the adrenal medulla. Therefore, pain responses, cardiovascular responses, and stress responses need to be considered as different aspects of a combined bodily reaction to surgery and trauma. It is important at the outset to understand that not all components of the stress response are suppressed together and that this is important when discussing different analgesic modalities (i.e. opioids vs regional anesthesia). For example, in terms of the use of fentanyl in the infant, the dose required to provide analgesia (1-5 mcg·kg(-1)) is less than that required for hemodynamic stability in response to stimuli (5-10 mcg·kg(-1)) (1) and that this in turn is less than that required to suppress most aspects of the stress response (25-50 mcg·kg(-1)) (2). In contrast to this considerable dose dependency, central local anesthetic blocks allow blockade of the afferent and efferent sympathetic pathways at relatively low doses resulting in profound suppression of hemodynamic and stress responses to surgery.

Pro con debate: the use of regional vs systemic analgesia for neonatal surgery.

In recent years the inclusion of regional techniques to pediatric anesthesia has transformed practice. Simple procedures such as caudal anesthesia with local anaesthetics can reduce the amounts of general anesthesia required and provide complete analgesia in the postoperative period while avoiding large amounts of opioid analgesia with potential side effects that can impair recovery. However, the application of central blocks (epidural and spinal local anesthesia) via catheters in the younger infant, neonate and even preterm neonate remains more controversial. The potential for such invasive maneuvers themselves to augment risk, can be argued to outweigh the benefits, others would argue that epidural analgesia can reduce the need for postoperative ventilation and that this not only facilitates surgery when intensive care facilities are limited, but also reduces cost in terms of PICU stay and recovery profile. Currently, opinions are divided and strongly held with some major units adopting this approach widely and others maintaining a more conservative stance to anesthesia for major neonatal surgery. In this pro-con debate the evidence base is examined, supplemented with expert opinion to try to provide a balanced overall view.

Analgesia and sedation after pediatric cardiac surgery.

In recent years, the importance of appropriate intra-operative anesthesia and analgesia during cardiac surgery has become recognized as a factor in postoperative recovery. This includes the early perioperative management of the neonate undergoing radical surgery and more recently the care surrounding fast-track and ultra fast-track surgery. However, outside these areas, relatively little attention has focused on postoperative sedation and analgesia within the pediatric intensive care unit (PICU). This reflects perceived priorities of the primary disease process over the supporting structure of PICU, with a generic approach to sedation and analgesia that can result in additional morbidities and delayed recovery. Management of the marginal patient requires optimisation of not only cardiac and other attendant pathophysiology, but also every aspect of supportive care. Individualized sedation and analgesia strategies, starting in the operating theater and continuing through to hospital discharge, need to be regarded as an important aspect of perioperative care, to speed the process of recovery.

Underrecognition of elevated blood pressure readings in children after early repair of coarctation of the aorta.

Hypertension after repair of coarctation of the aorta (CoA) is the outcome variable most closely associated with adverse long-term events such as stroke and myocardial infarction. This study sought to evaluate the outpatient management of casual blood pressure (BP) measurements in young children after early repair of CoA. A retrospective analysis was performed of clinical findings, echocardiographic data, casual BP recordings, and subsequent BP management of 114 children with CoA repair aged 1-13 years during 338 outpatient visits managed at two congenital cardiac centers. Children with associated significant congenital heart disease or corrective surgery after the age of 6 months were excluded from the study. Blood pressure was documented at 233 clinic visits (69%), and systolic BP (SBP) was above 95th percentile for age and sex in 45 instances (19%). This represented an elevated SBP recording for 31 children (27%), with two or more successive elevated recordings for 11 children (10%). Of 12 subjects receiving antihypertensive medication, three had inadequate BP control. Blood pressure is not documented at approximately 30% of outpatient visits of children with repaired CoA. When elevated BP is documented, in all cases no recorded action was taken. This may have significant implications for cardiovascular outcomes in this cohort of patients.

Surgical approach for aortic coarctation influences arterial compliance and blood pressure control.

BACKGROUND: Increased arterial stiffness is linked to hypertension in adults after surgical repair for coarctation of the aorta. We evaluated the influence of surgical approaches, namely, subclavian flap repair (SFR) and end-to-end anastomosis (EEA), on arterial stiffness, blood pressure, cardiac output, and cardiac baroreceptor function in a cohort of young children after coarctation repair to determine if the surgical approach influenced longer term blood pressure control. METHODS: We measured pulse wave velocity in 21 children with a mean age of 5 years, after early (less than 6 months) coarctation repair (SFR, n = 11; EEA, n = 10), and compared these with 18 matched controls. Blood pressure was recorded on three occasions from the right arm. Cardiac output was recorded using a transthoracic bioimpedence technique. We measured spontaneous baroreceptor reflex sensitivity to evaluate whether increased arterial stiffness was associated with reduced aortic baroreflex sensitivity. RESULTS: Right arm systolic blood pressure (108.3 + or - 3.5 mm Hg SFR versus 97.8 + or - 2.9 mm Hg EEA, p = 0.03) and pulse wave velocity (6.0 + or - 0.2 ms(-1) SFR versus 5.2 + or - 0.2 ms(-1) EEA, p = 0.02) were significantly greater in the SFR compared with EEA group. Blood pressure and pulse wave velocity were also higher in the SFR group compared with controls. These differences were not demonstrated when comparing the EEA group with controls. There was no difference in stroke volume, spontaneous baroreceptor reflex sensitivity, or heart rate or blood pressure variability between the groups. CONCLUSIONS: Young children undergoing SFR have higher blood pressure and stiffer upper limb arteries compared with matched children undergoing EEA. Our data suggest that better longer-term cardiovascular outcome is to be expected with the EEA surgical approach.

Religious practice, blood transfusion, and major medical procedures.

In this debate, we explore the dilemmas between the law, the ethical issues, the good clinical practice, and the wishes of the family. In the scenario chosen, the issues center around not only the senior family members but also of an older child with some rights to self-determination. There are no absolute rights or wrongs to this case, which is based on a synthesis of other actual clinical scenarios. The maze of considerations are not easy to negotiate, and in the final analysis, the surgeon and the anesthetist must also be comfortable with the decisions as they are the active elements that have to practically manage a clinical crisis should it occur. The participants in this debate are all UK based, and as such the legal standpoint reflects UK legislation, and the ethical and clinical reviews are strongly influenced by current attitudes within UK and Europe that may not be exactly mirrored in different cultural frameworks. However, in this article, it is the broad principles behind the differing responses that are important, which it is hoped will stimulate reflection of attitudes and management in different cultural frameworks.

The place of premedication in pediatric practice.

Behind the multiple arguments for and against the use of premedication, sedative drugs in children is a noble principle that of minimizing psychological trauma related to anesthesia and surgery. However, several confounding factors make it very difficult to reach didactic evidence-based conclusions. One of the key confounding issues is that the nature of expectations and responses for both parent and child vary greatly in different environments around the world. Studies applicable to one culture and to one hospital system (albeit multicultural) may not apply elsewhere. Moreover, the study of hospital-related distress begins at the start of the patient's journey and ends long after hospital discharge; it cannot be focused completely on just the moment of anesthetic induction. Taking an example from actual practice experience, the trauma caused by the actual giving of a premedication to a child who absolutely does not want it and may struggle may not be recorded in a study but could form a significant component of overall effect and later psychological pathology. Clearly, attitudes by health professionals and parents to the practice of routine pediatric premedication, vary considerably, often provoking strong opinions. In this pro-con article we highlight two very different approaches to premedication. It is hoped that this helps the reader to critically re-evaluate a practice, which was universal historically and now in many centers is more selective.

Current United Kingdom sedation practice in pediatric intensive care.

BACKGROUND: The aim of this study was to investigate the current practice of sedation, analgesia, and neuromuscular blockade in critically ill children on pediatric intensive care units (PICUs) in the UK and identify areas that merit further study. METHODS: Data were gathered in a prospective observational study of 338 critically ill children in 20 UK PICUs. RESULTS: There is considerable variation in clinical practice. A total of 24 different sedative and analgesic agents were used during the study. The most commonly used sedative and analgesic agents were midazolam and morphine. Four different neuromuscular blockers (NMBs) were used, most commonly vecuronium. There were differences in treatment between cardiac and noncardiac children, but there were a greater number of infants and neonates in the cardiac group. NMBs were used in 30% of mechanically ventilated patients. Withdrawal symptoms were reported in 13% of ventilated patients, relatively early in their stay; weaning sedative agents ('tapering') was apparently of no benefit. The use of clonidine in this setting was noted. Physical restraints were used in 7.4%. Propofol was used but in only 2.6% of patients, all over the age of 4 years, and not exceeding 2 mgxkg(-1)xh(-1). No side effects attributable to 'propofol syndrome' were noted. CONCLUSIONS: There is considerable heterogeneity of sedation techniques. NMBs are used in a large portion of this population. Withdrawal symptoms were associated with higher doses of sedation and greater lengths of stay and were not ameliorated by withdrawing sedation gradually ('tapering').

Spinal anesthesia with an indwelling catheter reduces the stress response in pediatric open heart surgery.

BACKGROUND: Extreme stress and inflammatory responses to open heart surgery are associated with increased morbidity and mortality. Based on both animal and adult human data, it was hypothesized that spinal anesthesia would be more effective at attenuating these responses than conventional high dose intravenous opioid techniques in infants and young children undergoing open heart surgery. METHODS: A prospective randomized controlled clinical trial was performed in 60 children aged up to 24 months undergoing open heart surgery. Patients were randomly assigned to receive either high-dose intravenous opioid or high-dose intravenous opioid plus spinal anesthesia. Spinal anesthesia was administered via an indwelling intrathecal catheter. RESULTS: Spinal anesthesia significantly reduced the stress responses as measured by plasma norepinephrine and epinephrine concentrations (both P < 0.05). Spinal anesthesia reduced plasma lactate concentrations (P < 0.05), but increased fluid requirements during the first postoperative day (P < 0.05). There were no differences in other cardiovascular parameters. CONCLUSIONS: Continuous spinal anesthesia reduces stress responses in infants and young children undergoing cardiac surgery with cardiopulmonary bypass more effectively than high-dose intravenous opioids alone.

Pain and stress in the human fetus.

It is not known if the fetus can actually feel pain, but noxious stimulation during fetal life does cause detectable stress responses. These responses cause both short and long-term changes in the central nervous system, which can affect subsequent pain behaviour. Reducing the stress response is known to be beneficial in children and adults and recent evidence suggests this is also true for the fetus. However, the optimal amount of suppression required and the best method of achieving this (opioid or regional anaesthesia techniques) remain unknown. Prevention and treatment of pain is a basic human right, regardless of age, and if the technique of fetal surgery is to progress then a greater understanding of nociception and the stress response is required.

Increased airway mucins after cardiopulmonary bypass associated with postoperative respiratory complications in children.

OBJECTIVE: Airway mucins may play an important role in the mechanism of respiratory complications after cardiopulmonary bypass in infants and children. Our aim was to measure airway mucin levels before and after cardiopulmonary bypass and to determine whether changes in mucin levels were associated with the development of respiratory complications. METHODS: Airway glycoprotein and mucins (MUC5AC, MUC5B, and MUC2) in serial small-volume airway lavage samples from 39 young children who underwent cardiac operations with cardiopulmonary bypass were measured by slot-blot assay with specific antimucin peptide antibodies. The relationship between mucin changes and post-cardiopulmonary bypass respiratory complications was investigated. Airway lavage samples were also collected from 11 children before and after operation without cardiopulmonary bypass, and changes in mucin levels were compared with those in subjects who underwent cardiopulmonary bypass. Airway lavage sample DNA was also measured to investigate the relationship between mucin changes and lung injury. RESULTS: Glycoprotein, MUC5AC, and MUC5B levels were significantly increased after cardiopulmonary bypass (P <.001) whereas MUC2 level was not. Children with respiratory complications showed significantly higher glycoprotein and MUC5AC levels than did children without respiratory complications before and after cardiopulmonary bypass (P <.05). Increase of total mucin (MUC5AC, MUC5B, and MUC2) during cardiopulmonary bypass showed positive correlation with DNA increase during cardiopulmonary bypass (r = 0.73), PaCO(2) (r = 0.62) and alveolar-arterial oxygen difference (r = 0.55) immediately after cardiopulmonary bypass. Increase of total mucin was associated with postoperative respiratory complications and their severity. There were no significant changes detected in airway mucin during operations without cardiopulmonary bypass. CONCLUSIONS: Airway mucins were increased during cardiopulmonary bypass, and this increase was associated with markers of lung injury after cardiopulmonary bypass and with the development of postoperative respiratory complications.

Electroencephalograph variables, drug concentrations and sedation scores in children emerging from propofol infusion anaesthesia.

BACKGROUND: Inadequate sedation or oversedation are common problems in Paediatric Intensive Care because of wide variations in drug response and the lack of objective tests for sedative depth. We undertook a pilot study to try to identify correlates of propofol drug concentration, electroencephalographic (EEG) variables and observed behaviour during a stepwise reduction in propofol infusion after paediatric cardiac surgery. METHODS: This was a prospective pilot study with 10 children (5 months to 8 years) emerging from propofol anaesthesia following cardiac surgery with cardiopulmonary bypass (CPB). Patients underwent a stepped wake-up from propofol anaesthesia during which the propofol infusion rate was decreased from 4 mg.kg(-1).h(-1) in 1 mg.kg(-1).h(-1) steps at 30 min intervals. EEG variables, propofol blood concentrations and clinical sedation scores (COMFORT scale) were recorded during the stepped wakeup. Analgesia was maintained with a standardized continuous infusion of fentanyl. RESULTS: : Mean (SD) whole blood propofol concentrations at arousal varied considerably [973 ng.ml(-1) (SD 523 ng.ml(-1))]. The summed ratio (SR) of high frequency to low frequency bands correlated with both propofol infusion rate (R2 value=0.47) and propofol blood concentrations (R2 value=0.64). The mean SR in deeply sedated patients was significantly different from that in the 5 min prior to wakening (6.84 vs 1.55, P=0.00002). There was no relationship between COMFORT scores and SR. CONCLUSIONS: In this group of patients receiving opioid analgesia and relatively high doses of propofol, sedation scores were unhelpful in predicting arousal. The SR correlated with propofol blood concentrations and clinical arousal and may have potential as a predictive tool for arousal in children.

Efficacy, safety, and pharmacokinetics of levobupivacaine with and without fentanyl after continuous epidural infusion in children: a multicenter trial.

BACKGROUND: Levobupivacaine, the levo-enantiomer of bupivacaine, is as potent as bupivacaine but less toxic. Therefore, the authors investigated the efficacy, safety, and pharmacokinetics of perioperative epidural levobupivacaine with and without fentanyl in children. METHODS: After Research Ethics Board approval and informed written consent, 120 healthy children aged 6 months to 12 yr who were scheduled to undergo urologic or abdominal surgery were randomized in a double-blinded and concealed manner to receive one of four epidural solutions as a continuous infusion for 24 h: 0.125% levobupivacaine; 0.0625% levobupivacaine; 1 mug/ml fentanyl; or the combination, 0.0625 levobupivacaine and 1 mug/ml fentanyl. After induction of anesthesia and tracheal intubation, a lumbar epidural catheter was sited, a loading dose was administered (0.75 ml/kg levobupivacaine, 0.175%), and the epidural infusion was commenced. The primary endpoint was the need for rescue analgesia (morphine) in the first 10 h after surgery. Pain, motor strength, and side effects were recorded for 24 h. Venous blood was collected from 18 children to determine the plasma concentrations of levobupivacaine and/or fentanyl before and 2, 4, 8, 16, 24, and 26 or 30 h after the start of the epidural infusion. RESULTS: Of the 114 children who were analyzed for intention to treat, a similar number of children in each group reached the 10-h mark. The time to the first dose of morphine in the first 10 h was less in the plain fentanyl group (P < 0.044). All other effects were similar among the four groups. The plasma concentration of levobupivacaine increased during the infusion period, reaching a maximum of 0.76 +/- 0.11 mug/ml in the 0.125% group and 0.48 +/- 0.12 mug/ml in the 0.0625% group by 24 h. The plasma concentration of fentanyl also increased steadily, reaching a maximum concentration of 0.37 +/- 0.11 ng/ml by 24 h. CONCLUSION: We conclude that 0.0625% levobupivacaine without fentanyl is an effective perioperative epidural solution in children when infused at a rate of 0.3 ml. kg-1. h-1. The plasma concentrations of 0.125% and 0.0625% levobupivacaine and fentanyl (1 mug/ml) at the end of a 24-h infusion are low.

Pharmacokinetics of propofol infusions in critically ill neonates, infants, and children in an intensive care unit.

BACKGROUND: Propofol is a commonly used anesthetic induction agent in pediatric anesthesia that, until recently, was used with caution as an intravenous infusion agent for sedation in pediatric intensive care. Few data have described propofol kinetics in critically ill children. METHODS: Twenty-one critically ill ventilated children aged 1 week to 12 yr were sedated with 4-6 mg. kg(-1).h(-1) of 2% propofol for up to 28 h, combined with a constant morphine infusion. Whole blood concentration of propofol was measured at steady state and for 24 h after infusion using high-performance liquid chromatography. RESULTS: A propofol infusion rate of 4 mg. kg(-1).h(-1) achieved adequate sedation scores in 17 of 20 patients. In 2 patients the dose was reduced because of hypotension, and 1 patient was withdrawn from the study because of a increasing metabolic acidosis. Mixed-effects population models were fitted to the blood propofol concentration data. The pharmacokinetics were best described by a three-compartment model. Weight was a significant covariate for all structural model parameters; Cl, Q2, Q3, V1, and V2 were proportional to weight. Estimates for these parameters were 30.2, 16.0, and 13.3 ml. kg(-1).min(-1) and 0.584 and 1.36 l/kg, respectively. The volume of the remaining peripheral compartment, V3, had a constant component (103 l) plus an additional weight-related component (5.67 l/kg). Values for Cl were reduced (typically by 26%) in children who had undergone cardiac surgery. CONCLUSIONS: Propofol kinetics are altered in very small babies and in children recovering from cardiac surgery. Increased peripheral distribution volume and reduced metabolic clearance following surgery causes prolonged elimination.