Hemodynamic response to ketamine in children with pulmonary hypertension

How Would I Treat My Own Chronic Thromboembolic Pulmonary Hypertension in the Perioperative Period?

Chronic thromboembolic pulmonary hypertension (CTEPH) results from an incomplete resolution of acute pulmonary embolism, leading to occlusive organized thrombi, vascular remodeling, and associated microvasculopathy with pulmonary hypertension (PH). A definitive CTEPH diagnosis requires PH confirmation by right-heart catheterization and evidence of chronic thromboembolic pulmonary disease on imaging studies. Surgical removal of the organized fibrotic material by pulmonary endarterectomy (PEA) under deep hypothermic circulatory arrest represents the treatment of choice. One-third of patients with CTEPH are not deemed suitable for surgical treatment, and medical therapy or interventional balloon pulmonary angioplasty presents alternative treatment options. Pulmonary endarterectomy in patients with technically operable disease significantly improves symptoms, functional capacity, hemodynamics, and quality of life. Perioperative mortality is <2.5% in expert centers where a CTEPH multidisciplinary team optimizes patient selection and ensures the best preoperative optimization according to individualized risk assessment. Despite adequate pulmonary artery clearance, patients might be prone to perioperative complications, such as right ventricular maladaptation, airway bleeding, or pulmonary reperfusion injury. These complications can be treated conventionally, but extracorporeal membrane oxygenation has been included in their management recently. Patients with residual PH post-PEA should be considered for medical or percutaneous interventional therapy.

Combination of high-flow nasal oxygen and ketamine/dexmedetomidine sedation for diagnostic catheterization in a child with pulmonary arterial hypertension: a case report

Pulmonary hypertension is associated with significant risk of perioperative life-threatening events. We present a case of a 12-year-old child with severe pulmonary arterial hypertension who successfully underwent diagnostic cardiac catheterization under ketamine and dexmedetomidine sedation with the support of high-flow nasal oxygen. Ketamine and dexmedetomidine are reported to have minimal effect on pulmonary vasculature in children with pulmonary hypertension and can be safely used in this population along with its lack of respiratory depression. Positive pressure generated by high-flow nasal oxygen improves upper airway patency, prevents micro-atelectasis, and is shown to improve the effectiveness of ventilation and oxygenation in patients under sedation breathing spontaneously. The presented strategy may contribute to enhancing the safety and effectiveness of procedural sedation for children with life-threatening pulmonary hypertension.

Surgery and Anesthesia in Patients with Pulmonary Hypertension

Pulmonary hypertension is characterized by right ventricular impairment and a reduced ability to compensate for hemodynamic insults. Consequently, surgery can be challenging but is increasingly considered in view of available specific therapies and improved longer term survival. Optimal management requires a multidisciplinary patient-centered approach involving surgeons, anesthetists, pulmonary hypertension clinicians, and intensivists. The optimal pathway involves risk:benefit assessment for the proposed operation, optimization of pulmonary hypertension and any comorbidities, the appropriate anesthetic approach for the specific procedure and patient, and careful monitoring and management in the postoperative period. Where patients are carefully selected and meticulously managed, good outcomes can be achieved.

Prospective observational study on the use of continuous intravenous ketamine and propofol infusion for prolonged sedation in critical care

INTRODUCTION

Analgesia and sedation are a priority in paediatric intensive care. The combination of ketamine and propofol is a possible option in patients requiring prolonged or difficult sedation and to reduce the use of benzodiazepines and opiates. The aim of this study was to assess the efficacy and safety of combination ketamine and propofol in continuous infusion for prolonged analgesia/sedation in the paediatric intensive care setting.

PATIENTS AND METHODS

Prospective, observational single-group cohort study in patients aged 1 month to 16 years admitted to the paediatric intensive care unit in 2016-2018 that received ketamine and propofol in continuous infusion for analgesia and sedation. We collected data on demographic and clinical characteristics, analgesia and sedation scores (MAPS, COMFORT-B and SOPHIA), haemodynamic parameters and adverse events.

RESULTS

The study included 32 patients. The maximum dose of ketamine was 1.5 mg/kg/h (interquartile range [IQR], 1-2 mg/kg/h) and the infusion duration was 5 days (IQR, 3-5 days). The maximum dose of propofol was 3.2 mg/kg/h (IQR, 2.5-3.6 mg/kg/h) and the infusion duration, 5 days (IQR, 3-5 days). Thirty (93.7%) patients had previously received midazolam and 29 (90.6%) fentanyl. Analgesia scores did not change after initiation of the ketamine and propofol infusion. There was a statistically significant increase in the COMFORT-B score, but the score remained in the adequate sedation range (12-17). There were small but statistically significant decreases in the mean arterial pressure (from 64 mmHg to 60 mmHg; P = .006) and the diastolic blood pressure (from 50.5 to 48 mmHg; P = .023) 1 h after the initiation of the ketamine and propofol infusion, but this difference was not observed 12 h later and did not require administration of vasoactive drugs. No other major adverse events were detected during the infusion.

CONCLUSIONS

The combination of ketamine and propofol in continuous infusion is a safe treatment in critically ill children that makes it possible to achieve an appropriate level of analgesia and sedation without relevant haemodynamic repercussions.

Perioperative approach to precapillary pulmonary hypertension in non-cardiac non-obstetric surgery

Pulmonary hypertension (PH) confers a significant challenge in perioperative care. It is associated with substantial morbidity and mortality. A considerable amount of information about management of patients with PH has emerged over the past decade. However, there is still a paucity of information to guide perioperative evaluation and management of these patients. Yet, a satisfactory outcome is feasible by focusing on elaborate disease-adapted anaesthetic management of this complex disease with a multidisciplinary approach. The cornerstone of the peri-anaesthetic management of patients with PH is preservation of right ventricular (RV) function with attention on maintaining RV preload, contractility and limiting increase in RV afterload at each stage of the patient's perioperative care. Pre-anaesthetic evaluation, choice of anaesthetic agents, proper fluid management, appropriate ventilation, correction of hypoxia, hypercarbia, acid-base balance and pain control are paramount in this regard. Essentially, the perioperative management of PH patients is intricate and multifaceted. Unfortunately, a comprehensive evidence-based guideline is lacking to navigate us through this complex process. We conducted a literature review on patients with PH with a focus on the perioperative evaluation and suggest management algorithms for these patients during non-cardiac, non-obstetric surgery.

Update on Perioperative Pediatric Pulmonary Hypertension Management

Pediatric pulmonary hypertension is a disease that has many etiologies and can present anytime during childhood. Its newly revised hemodynamic definition follows that of adult pulmonary hypertension: a mean pulmonary artery pressure >20 mmHg. However, the pediatric definition stipulates that the elevated pressure must be present after the age of three months. The definition encompasses many different etiologies, and diagnosis often involves a combination of noninvasive and invasive testing. Treatment often is extrapolated from adult studies or based on expert opinion. Moreover, although general anesthesia may be required for pediatric patients with pulmonary hypertension, it poses certain risks. A thoughtful, multidisciplinary approach is needed to deliver excellent perioperative care.

Perioperative management of patients with pulmonary hypertension undergoing non-cardiothoracic, non-obstetric surgery: a systematic review and expert consensus statement

BACKGROUND

The risk of complications, including death, is substantially increased in patients with pulmonary hypertension (PH) undergoing anaesthesia for surgical procedures, especially in those with pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH). Sedation also poses a risk to patients with PH. Physiological changes including tachycardia, hypotension, fluid shifts, and an increase in pulmonary vascular resistance (PH crisis) can precipitate acute right ventricular decompensation and death.

METHODS

A systematic literature review was performed of studies in patients with PH undergoing non-cardiac and non-obstetric surgery. The management of patients with PH requiring sedation for endoscopy was also reviewed. Using a framework of relevant clinical questions, we review the available evidence guiding operative risk, risk assessment, preoperative optimisation, and perioperative management, and identifying areas for future research.

RESULTS

Reported 30 day mortality after non-cardiac and non-obstetric surgery ranges between 2% and 18% in patients with PH undergoing elective procedures, and increases to 15-50% for emergency surgery, with complications and death usually relating to acute right ventricular failure. Risk factors for mortality include procedure-specific and patient-related factors, especially markers of PH severity (e.g. pulmonary haemodynamics, poor exercise performance, and right ventricular dysfunction). Most studies highlight the importance of individualised preoperative risk assessment and optimisation and advanced perioperative planning.

CONCLUSIONS

With an increasing number of patients requiring surgery in specialist and non-specialist PH centres, a systematic, evidence-based, multidisciplinary approach is required to minimise complications. Adequate risk stratification and a tailored-individualised perioperative plan is paramount.

Preoperative Assessment and Perioperative Management of the Patient with Pulmonary Vascular Disease

The incidence of pulmonary hypertension (PH) in patients undergoing noncardiac surgery has increased steadily over the past decade. Patients with known PH have significantly higher perioperative morbidity and mortality than those without PH. Moreover, a substantial number of patients may have occult disease. It, therefore, is of paramount importance for perioperative providers to recognize high-risk patients and treat them appropriately. This review first provides an overview of PH pathophysiology, then estimates the perioperative incidence of PH and its impact on surgical outcomes, and finally outlines a perioperative management strategy.

Current understanding and perioperative management of pediatric pulmonary hypertension

Pediatric pulmonary hypertension is a complex disease with multiple, diverse etiologies affecting the premature neonate to the young adult. Pediatric pulmonary arterial hypertension, whether idiopathic or associated with congenital heart disease, is the most commonly discussed form of pediatric pulmonary hypertension, as it is progressive and lethal. However, neonatal forms of pulmonary hypertension are vastly more frequent, and while most cases are transient, the risk of morbidity and mortality in this group deserves recognition. Pulmonary hypertension due to left heart disease is another subset increasingly recognized as an important cause of pediatric pulmonary hypertension. One aspect of pediatric pulmonary hypertension is very clear: anesthetizing the child with pulmonary hypertension is associated with a significantly heightened risk of morbidity and mortality. It is therefore imperative that anesthesiologists who care for children with pulmonary hypertension have a firm understanding of the pathophysiology of the various forms of pediatric pulmonary hypertension, the impact of anesthesia and sedation in the setting of pulmonary hypertension, and anesthesiologists' role as perioperative experts from preoperative planning to postoperative disposition. This review summarizes the current understanding of pediatric pulmonary hypertension physiology, preoperative risk stratification, anesthetic risk, and intraoperative considerations relevant to the underlying pathophysiology of various forms of pediatric pulmonary hypertension.

NMDA-Type Glutamate Receptor Activation Promotes Vascular Remodeling and Pulmonary Arterial Hypertension

BACKGROUND

Excessive proliferation and apoptosis resistance in pulmonary vascular cells underlie vascular remodeling in pulmonary arterial hypertension (PAH). Specific treatments for PAH exist, mostly targeting endothelial dysfunction, but high pulmonary arterial pressure still causes heart failure and death. Pulmonary vascular remodeling may be driven by metabolic reprogramming of vascular cells to increase glutaminolysis and glutamate production. The N-methyl-d-aspartate receptor (NMDAR), a major neuronal glutamate receptor, is also expressed on vascular cells, but its role in PAH is unknown.

METHODS

We assessed the status of the glutamate-NMDAR axis in the pulmonary arteries of patients with PAH and controls through mass spectrometry imaging, Western blotting, and immunohistochemistry. We measured the glutamate release from cultured pulmonary vascular cells using enzymatic assays and analyzed NMDAR regulation/phosphorylation through Western blot experiments. The effect of NMDAR blockade on human pulmonary arterial smooth muscle cell proliferation was determined using a BrdU incorporation assay. We assessed the role of NMDARs in vascular remodeling associated to pulmonary hypertension, in both smooth muscle-specific NMDAR knockout mice exposed to chronic hypoxia and the monocrotaline rat model of pulmonary hypertension using NMDAR blockers.

RESULTS

We report glutamate accumulation, upregulation of the NMDAR, and NMDAR engagement reflected by increases in GluN1-subunit phosphorylation in the pulmonary arteries of human patients with PAH. K_v channel inhibition and type A-selective endothelin receptor activation amplified calcium-dependent glutamate release from human pulmonary arterial smooth muscle cell, and type A-selective endothelin receptor and platelet-derived growth factor receptor activation led to NMDAR engagement, highlighting crosstalk between the glutamate-NMDAR axis and major PAH-associated pathways. The platelet-derived growth factor-BB-induced proliferation of human pulmonary arterial smooth muscle cells involved NMDAR activation and phosphorylated GluN1 subunit localization to cell-cell contacts, consistent with glutamatergic communication between proliferating human pulmonary arterial smooth muscle cells via NMDARs. Smooth-muscle NMDAR deficiency in mice attenuated the vascular remodeling triggered by chronic hypoxia, highlighting the role of vascular NMDARs in pulmonary hypertension. Pharmacological NMDAR blockade in the monocrotaline rat model of pulmonary hypertension had beneficial effects on cardiac and vascular remodeling, decreasing endothelial dysfunction, cell proliferation, and apoptosis resistance while disrupting the glutamate-NMDAR pathway in pulmonary arteries.

CONCLUSIONS

These results reveal a dysregulation of the glutamate-NMDAR axis in the pulmonary arteries of patients with PAH and identify vascular NMDARs as targets for antiremodeling treatments in PAH.

Successful Surgical Repair and Perioperative Management of 6-Month-Old With Total Anomalous Pulmonary Venous Return in a Developing Country: Considerations for the Treatment of Pulmonary Hypertension

Total anomalous pulmonary venous return (TAPVR) is a rare congenital cardiac defect, accounting for 1.5-3% of cases of congenital heart disease. With prenatal ultrasonography, the majority of these patients are diagnosed in utero with definitive surgery performed during the neonatal period. However, as prenatal screening may not be available in developing countries, patients may present in later infancy. We present successful surgical repair of a 6-month-old infant with TAPVR who presented for medical care at 5 months of age in Lima, Peru. The late presentation of such infants and the limited resources available for the treatment of elevated pulmonary vascular resistance may impact successful surgical correction of such defects. The perioperative care of such infants in developing countries is discussed and strategies for managing postoperative pulmonary hypertension is reviewed.

Perioperative events in children with pulmonary hypertension undergoing non-cardiac procedures

Prior limited research indicates that children with pulmonary hypertension (PH) have higher rates of adverse perioperative outcomes when undergoing non-cardiac procedures and cardiac catheterizations. We examined a single-center retrospective cohort of children with active or pharmacologically controlled PH who underwent cardiac catheterization or non-cardiac surgery during 2006–2014. Preoperative characteristics and perioperative courses were examined to determine relationships between the severity or etiology of PH, type of procedure, and occurrence of major and minor events. We identified 77 patients who underwent 148 procedures at a median age of six months. The most common PH etiologies were bronchopulmonary dysplasia (46.7%), congenital heart disease (29.9%), and congenital diaphragmatic hernia (14.3%). Cardiac catheterizations (39.2%), and abdominal (29.1%) and central venous access (8.9%) were the most common procedures. Major events included failed planned extubation (5.6%), postoperative cardiac arrest (4.7%), induction or intraoperative cardiac arrest (2%), and postoperative death (1.4%). Major events were more frequent in patients with severe baseline PH (P = 0.006) and the incidence was associated with procedure type (P = 0.05). Preoperative inhaled nitric oxide and prostacyclin analog therapies were associated with decreased incidence of minor events (odds ratio [OR] = 0.32, P = 0.046 and OR = 0.24, P = 0.008, respectively), but no change in the incidence of major events. PH etiology was not associated with events (P = 0.24). Children with PH have increased risk of perioperative complications; cardiac arrest and death occur more frequently in patients with severe PH and those undergoing thoracic procedures. Risk may be modified by using preoperative pulmonary vasodilator therapy and lends itself to further prospective studies.

Outstanding contribution to pediatric anesthesiology: An interview with Dr. Robert H. Friesen

Dr. Robert H. Friesen, (1946-) Professor of Anesthesiology, Children's Hospital Colorado, University of Colorado, Anschutz Medical Campus, has played a pivotal and pioneering role in the development of pediatric and congenital cardiac anesthesiology. His transformative research included the study of the hemodynamic effects of inhalational and intravenous anesthetic agents in the newborn and the effects of anesthetic agents on pulmonary vascular resistance in patients with pulmonary hypertension. As a model clinician-scientist, educator, and administrator, he changed the practice of pediatric anesthesia and shaped the careers of hundreds of physicians-in-training, imbuing them with his core values of honesty, integrity, and responsibility. Based on a series of interviews with Dr. Friesen, this article reviews a career that advanced pediatric and congenital cardiac anesthesia during the formative years of the specialties.

The Anesthetic Challenges of Lung Biopsy-Associated Intrathoracic Hemorrhage in a Child With Suprasystemic Pulmonary Hypertension

Children with suspected pulmonary hypertension must undergo extensive and invasive evaluations to establish a definitive diagnosis. A previously healthy 4-year old girl, newly diagnosed with suprasystemic pulmonary hypertension required multiple lung biopsies. Each procedure was associated with significant bleeding. The challenging anesthetic management of lung biopsy in the presence of suprasystemic pulmonary hypertension is described.