Welcome to PICU Doc On Call, where Dr. Pradip Kamat from Children’s Healthcare of Atlanta/Emory University School of Medicine and Dr. Rahul Damania from Cleveland Clinic Children’s Hospital delve into the intricacies of Pediatric Intensive Care Medicine. In this special episode of PICU Doc on Call shorts, we dissect the Alveolar Gas Equation—a fundamental concept in respiratory physiology with significant clinical relevance.

Key Concepts Covered:

• Alveolar Gas Equation Demystified: Dr. Rahul explains the Alveolar Gas Equation, which calculates the partial pressure of oxygen in the alveoli (PAO2). This equation, PAO2 = FiO2 (Patm - PH2O) - (PaCO2/R), is essential in understanding hypoxemia and the dynamics of gas exchange in the lungs.
• Calculating PAO2: Using the Alveolar Gas Equation, the hosts demonstrate how to calculate PAO2 at sea level, emphasizing the influence of atmospheric pressure, fraction of inspired oxygen (FiO2), water vapor pressure, arterial carbon dioxide pressure (PaCO2), and respiratory quotient (R) on oxygenation.
• A-a Gradient and Hypoxemia: The A-a gradient, derived from the Alveolar Gas Equation, is discussed in the context of hypoxemia evaluation. Understanding the causes of hypoxemia, including ventilation/perfusion (V/Q) mismatch, anatomical shunt, diffusion defects, and hypoventilation, is crucial for clinical diagnosis and management.
• Clinical Scenarios and A-a Gradient Interpretation: Through a clinical scenario, the hosts elucidate how different conditions affect the A-a gradient and oxygenation, providing insights into respiratory pathophysiology and differential diagnosis.
• Clinical Implications and Management Strategies: The hosts highlight the clinical significance of the Alveolar Gas Equation in assessing oxygenation status, diagnosing gas exchange abnormalities, and tailoring respiratory management strategies in the pediatric intensive care setting.

Key Takeaways:

• Utility of the Alveolar Gas Equation: Understanding and applying the Alveolar Gas Equation is essential for evaluating oxygenation and diagnosing respiratory abnormalities.
• Interpreting A-a Gradient: A normal A-a gradient suggests alveolar hypoventilation as the likely cause of hypoxemia, whereas elevated gradients indicate other underlying pathologies.
• Clinical Relevance: Recognizing the clinical implications of the Alveolar Gas Equation aids in accurate diagnosis and optimal management of respiratory conditions in pediatric intensive care patients.

Conclusion:

Join Dr. Kamat and Dr. Damania as they unravel the complexities of the Alveolar Gas Equation, providing valuable insights into respiratory physiology and its clinical applications. Don’t forget to subscribe, share your feedback, and visit picudoconcall.org for more educational content and resources.

References:

• Fuhrman & Zimmerman - Textbook of Pediatric Critical Care Chapter: Physiology of the respiratory system. Chapter 42. Khemani et al. Pages 470-481
• Rogers textbook of Pediatric intensive care: Chapter 44....

Welcome to PICU Doc On Call, A Podcast Dedicated to Current and Aspiring Intensivists.

• Hosts:
• Dr. Pradip Kamat: Children’s Healthcare of Atlanta/Emory University School of Medicine
• Dr. Rahul Damania: Cleveland Clinic Children’s Hospital

Introduction:

• Pediatric Intensive Care Unit (PICU) physicians passionate about medical education in the acute care pediatric setting
• Episode focus: A case of a 23-month-old ex-28 week premie presenting with sudden high fever and rapidly rising ETCO2 during surgery

Case Presentation:

• Presented by Dr. Rahul Damania
• 23-month-old ex-28 week premie intubated during hernia repair surgery
• Noticed rapidly rising ETCO2, unprovoked tachycardia, and elevated temperature
• Transferred to PICU, exhibiting rigidity, clenched jaw, metabolic acidosis, and elevated lactate.
• Consideration of Malignant Hyperthermia (MH) crisis

Key Points:

• Elevated temperature, hypercapnia, metabolic acidosis, and unprovoked tachycardia raise concern for MH
• Organized discussion on pathophysiology, clinical signs, symptoms, and management

Multiple Choice Question:

• Diagnosis of MH crisis during scoliosis repair
• Correct Answer: D) Sarcoplasmic reticulum
• Dantrolene acts on the sarcoplasmic reticulum to inhibit calcium release, crucial in MH management

Clinical Presentation of MH Crisis:

• Tachycardia, acidosis, muscle stiffness, and hyperthermia are hallmark features
• Potential life-threatening complications underscore the urgency of recognition and treatment

Triggers and Pathophysiology of MH Crisis:

• Triggered by inhalational agents and depolarizing neuromuscular blocking agents
• Pathophysiology involves defective Ryanodine receptor leading to uncontrolled calcium release

Differential Diagnosis:

• Includes sepsis, thyroid storm, pheochromocytoma, and neuroleptic malignant syndrome
• Differentiation from similar conditions crucial for accurate management

Diagnostic Approach:

• High clinical suspicion
• Genetic testing (ryanodine...

Show Introduction

• Welcome to PICU Doc On Call, a podcast dedicated to current and aspiring intensivists.
• Hosted by Dr. Pradip Kamat and Dr. Rahul Damania

Case Presentation

• A 14-year-old female with a history of depression and oppositional defiant disorder presents with dizziness, slurring speech, and is pale appearance.
• The mother noticed symptoms of dizziness, stumbling, and sleepiness.
• The patient had a prior suicide attempt.
• Vital signs: HR 50 bpm, BP 75/40, GCS 10.
• The initial workup reveals hyperglycemia, and she is stabilized and admitted to the PICU.

Key Aspects of Ingestion Work-up

• History and physical exam are crucial.
• Stratify acute or chronic ingestions.
• Consider baseline medications and coingestants.
• Perform initial screening examination to identify immediate measures for stabilization.

Diagnostic Studies

• Pulse oximetry, continuous cardiac monitoring, ECG, capillary glucose measurement.
• Serum acetaminophen, ASA levels
• Consider extended toxicology screen.

Differentiating CCB vs. Beta-Blocker Overdose

• ECG findings: PR interval prolongation and Bradydysrhythmia suggest CCB poisoning.
• Hyperglycemia in non-diabetic patients may indicate CCB overdose

Approach to CCB Overdose

• Initial resuscitation and stabilization
• ABC approach
• Consult Poison Control Center
• Empiric use of glucagon, IV fluids, and vasopressors
• Consideration of orogastric lavage and activated charcoal

Specific Medical Therapies

• Vasopressors: norepinephrine/epinephrine infusion
• Atropine for bradycardia
• IV calcium salts to overcome cardiovascular effects
• High-dose insulin and dextrose for myocardial function
• Investigational therapies: methylene blue, lipid emulsion

Procedures

• Transvenous pacemaker placement if needed
• ECMO in refractory...

Hosts:

• Pradip Kamat, Children’s Healthcare of Atlanta/Emory University School of Medicine
• Rahul Damania, Cleveland Clinic Children’s Hospital

Introduction

Today, we discuss the case of an 8-month-old infant with severe bronchospasm and abnormal blood gas. We'll delve into the epidemiology, pathophysiology, and evidence-based management of acute bronchiolitis.

Case Summary

An 8-month-old infant presented to the ER with decreased alertness following worsening work of breathing, preceded by URI symptoms. The infant was intubated and transferred to the PICU, testing positive for RSV. Initial blood gas showed 6.8/125/-4, and CXR revealed massive hyperinflation. Vitals: HR 180, BP 75/45, SPO2 92% on 100% FIO2, RR 12 (prior to intubation), now around 16 on the ventilator, afebrile.

Discussion Points

• Etiology & Pathogenesis: Bronchiolitis is primarily caused by RSV, with other viruses and bacteria playing a role. RSV bronchiolitis is the most common cause of hospitalization in infants, particularly in winter months. Immuno-pathology involves an unbalanced immune response and can lead to various extra-pulmonary manifestations.
• Diagnosis: Diagnosis is clinical, based on history and examination. Key signs include upper respiratory symptoms followed by lower respiratory distress. Blood gas, chest radiography, and viral testing are generally not recommended unless warranted by severe symptoms or clinical deterioration.
• Management Framework: For patients requiring PICU admission, focus on oxygenation and hydration. High-flow therapy and nasal continuous positive airway pressure (CPAP) can be used. Hydration and feeding support are crucial. Antibiotics, steroids, and bronchodilators are generally not recommended. Mechanical ventilation and ECMO may be necessary in severe cases.
• Immunoprophylaxis & Nosocomial Infection Prevention: Palivizumab and nirsevimab are used for RSV prevention in high-risk infants. Strict infection control measures, including hand hygiene and isolation, are essential to prevent nosocomial infections.

Conclusion

RSV bronchiolitis is a common and potentially severe respiratory illness in infants. Management focuses on supportive care, with a careful balance between oxygenation and hydration. Immunoprophylaxis and infection control are crucial in preventing the spread of the virus.

Thank you for listening to our episode on acute bronchiolitis. Please subscribe, share your feedback, and visit our website at picudoconcall.org for more resources. Stay tuned for our next episode!

References

Rogers - Textbook of Pediatric Critical Care Chapter 49: Pneumonia and Bronchiolitis. De Carvalho et al. page 797-823

Reference 1: Dalziel, Stuart R; Haskell, Libby; O'Brien, Sharon; Borland, Meredith L; Plint, Amy C; Babl, Franz E; Oakley, Ed. Bronchiolitis. The Lancet. , 2022, Vol.400(10349), p.392-406. DOI: 10.1016/S0140-6736(22)01016-9; PMID:...

Hosts:

• Pradip Kamat, Children’s Healthcare of Atlanta/Emory University School of Medicine
• Rahul Damania, Cleveland Clinic Children’s Hospital

Case Introduction:

• 6-year-old patient admitted to PICU with severe pneumonia complicated by pediatric Acute Respiratory Distress Syndrome (pARDS).
• Presented with respiratory distress, hypoxemia, and significant respiratory acidosis.
• Required intubation and mechanical ventilation.
• Despite initial interventions, condition remained precarious with persistent hypercapnia.

Physiology Concept: Dead Space

• Defined as the volume of air that does not participate in gas exchange.
• Consists of anatomic dead space (large airways) and physiologic dead space (alveoli).
• Physiologic dead space reflects ventilation-perfusion mismatch.

Pathological Dead Space:

• Occurs due to conditions disrupting pulmonary blood flow or ventilation.
• Common in conditions like pulmonary embolism, severe pneumonia, or ARDS.

Clinical Implications:

• Increased dead space fraction (DSF) in PARDS is a prognostic factor linked to severity and mortality.
• Elevated DSF indicates worse lung injury and inefficient gas exchange.
• DSF can be calculated using the formula: DSF = (PaCO2 – PetCO2) / PaCO2.

Practical Management:

• Optimize Mechanical Ventilation
• Enhance Perfusion
• Consider Positioning (e.g., prone positioning)

Summary of Physiology Concepts:

• Bohr equation for physiologic dead space.
• Importance of lung-protective ventilation strategies.
• Monitoring and trending dead space fraction.
• Strategies to improve airway patency and mucociliary clearance.

Connect with us!

• PICU Doc on Call provides concise explanations of critical concepts in pediatric intensive care.
• Feedback, subscriptions, and reviews are encouraged.
• Visit picudoconcall.org for episodes and Doc on Call infographics.

Today's episode promises an insightful exploration into a unique case centered on retropharyngeal abscess in the PICU, offering a comprehensive analysis of its clinical manifestations, pathophysiology, diagnostic strategies, and evidence-based management approaches.

Today, we unravel the layers of a compelling case involving a 9-month-old with a retropharyngeal abscess, delving into the intricacies of its diagnosis, management, and the critical role played by PICU specialists. Join us as we navigate through the clinical landscape of RPA, providing not only a detailed analysis of the presented case but also valuable takeaways for professionals in the field and those aspiring to enter the world of pediatric intensive care. Welcome to PICU Doc On Call – where MED-ED meets the real challenges of the PICU.

• Patient: 9-month-old male with rapid symptom onset, left neck swelling, fever, noisy breathing, and decreased oral intake.
• Initial presentation: Left neck swelling, limited neck mobility, and deteriorating condition.
• Imaging: Neck X-ray and CT scan with IV contrast confirmed Retropharyngeal Abscess (RPA).
• Management: High-flow nasal cannula, intravenous antibiotics, and consultation with ENT. PICU admission for comprehensive care.

• Rapid Symptom Onset
• Neck Swelling & Drooling
• Limited Neck Mobility

• A previously healthy 9-month-old male with a recent upper respiratory infection, presenting with rapid-onset left neck swelling, fever, and respiratory distress. Imaging suggestive of a Retropharyngeal Abscess, requiring urgent PICU management for airway protection and antibiotic therapy.

• Anatomy of retropharyngeal space
• Rapid communication of infections via lymph nodes
• Infection sources: dental issues, trauma, localized infections (e.g., otitis, URI)

• Airway compromise and posterior mediastinitis
• Progression from cellulitis to abscess
• Microbial suspects: Group A Streptococcus, anaerobes, Staphylococcus aureus, Haemophilus influenza, Klebsiella, Mycobacterium avium-intracellulare

• Seen predominantly in children aged 3-4 years
• Non-specific symptoms in the acute setting
• Pronounced symptoms in PICU: neck pain, stiffness, torticollis, muffled voice, stridor, respiratory distress

Today, Dr. Pradip Kamat (Children’s Healthcare of Atlanta/Emory University School of Medicine) and Dr. Rahul Damania (Cleveland Clinic Children’s Hospital), are excited to speak with Matthew Kirschen, MD, PhD, FAAN, FNCS, regarding a very sensitive topic involving pediatric brain death guidelines published in 'Neurology' in October 2023. Dr. Matthew Kirschen, a leader in pediatric neurocritical care and one of the authors of the new guidelines.

Guest Introduction:

Dr. Matthew Kirschen is an Assistant Professor of Anesthesiology and Critical Care Medicine, Pediatrics, and Neurology at the Children's Hospital of Philadelphia. A proud alumnus of Brandeis University and Stanford, where he secured both his MD and PhD in neuroscience. Dr. Kirschen’s journey includes a residency at Stanford followed by a unique dual fellowship in neurology and pediatric critical care at CHOP. Notably, he's among the rare professionals dual-boarded in both PCCM and Neurology.

Dr. Kirschen’s tireless endeavors in pediatric neuro-critical care, especially his work on multimodal neuro-monitoring to detect and prevent brain injuries in critically ill children, have garnered significant attention. His expertise also extends to predicting recovery post-severe brain injuries. Pertinent to today's discussion, Dr. Kirschen has displayed a keen interest in the precise diagnosis of brain death and proudly stands as one of the authors of the new guidelines on the topic of Pediatric and Adult Brain death/death by neurologic criteria.

Discussion:

1. Understanding Brain Death Criteria:

• Brain Death/Death by Neurologic Criteria (BD/DNC) declared with permanent cessation of all brain functions, including brainstem
• Important considerations before BD/DNC determination:
• No evaluation in infants < 37 weeks corrected gestational age
• Absence of coma, intact brainstem reflexes, and spontaneous breathing inconsistent with BD/DNC

2. Who Can Perform BD/DNC Evaluations:

• Attending clinicians must be credentialed and trained in BD/DNC evaluation.
• Two attending clinicians are needed for evaluation, with exceptions for advanced practice providers.

3. Prerequisites for BD/DNC Determination:

• Importance of identifying the etiology of BD/DNC to avoid reversible processes
• Observation periods based on age and type of brain injury
• Maintaining core body temperature before evaluation

4. Blood Pressure Management:

• Hypotension can lead to impermanent coma; clinicians should manage with fluids or vasopressors.
• Specific blood pressure targets for different ECMO support types

5. Medication Considerations:

• Excluding...

Today’s case presentation involves a 2-year-old girl who was previously healthy and was admitted to the Pediatric Intensive Care Unit (PICU) for acute respiratory distress characterized by increased work of breathing and wheezing.

A 2-year-old girl with acute respiratory distress due to RSV infection

• Presented with increased work of breathing, wheezing, and no fever
• Started on High Flow Nasal Cannula (HFNC) therapy in the PICU

Key Elements:

• Prodrome of URI symptoms
• Increased respiratory effort (nasal flaring, intercostal retractions, decreased lung base air entry)
• HFNC improved the work of breathing and oxygen saturation

Washout of Nasopharyngeal Dead Space:

• HFNC clears nasopharyngeal dead space, improving oxygen efficiency.
• Reduces re-breathing of CO2 from the anatomical dead space.
• Enhances ventilation efficiency and oxygenation.

Reduction in Upper Airway Resistance:

• HFNC reduces resistance in the upper airway.
• Delivers rapid gas flow matching or exceeding natural inhalation rate.
• Eases breathing, especially in neonates and infants with narrow airways.

Optimal Conditioning of Gas:

• HFNC delivers heated and humidified oxygen, matching the body's conditions.
• Reduces energy expenditure and risk of airway irritation
• More comfortable and effective compared to cold, dry air delivery

• HFNC generates minimal and variable PEEP.
• Amount of PEEP depends on factors like flow rate and cannula size
• Not as high or consistent as other respiratory support devices

• A 2022 CHEST study by Khemani et al. on children with bronchiolitis challenged the conventional understanding of HFNC's mechanisms.
• HFNC primarily reduces breathing effort but does not consistently increase lung volume (EELV) or tidal volume (VT).
• Reduction in the pressure rate product (PRP) indicates decreased breathing effort, but not significant alterations in EELV or VT.