spa meeting reviews

CRNA Symposium

By Jamie Furstein, CRNA
Cincinnati Children’s Hospital Medical Center
Cincinnati, OH

The CRNA Special Interest Group put together an impressive program for the second annual CRNA Symposium.  The symposium was moderated by Jamie Furstein, CRNA (Cincinnati Children’s Hospital Medical Center, Cincinnati) and featured a diverse group of lecturers with varying areas of clinical expertise from around the country.  Each of the four presentations proved to be riveting and highlighted novel approaches to ensuring the delivery of safe, effective anesthetic care to the pediatric population.  A question and answer session followed each presentation.   

Tetsu Uejima, MD (A.I. DuPont Hospital for Children, Delaware) led off the morning with his presentation “Safety and Quality in Pediatric Anesthesia: Building Blocks”.   Dr. Uejima highlighted the differences between patient safety, quality assurance, and quality improvement.  While unique concepts, it was clear that an understanding of the interplay between these three concepts facilitates improving safety and quality in pediatric anesthesia.  Although not all adverse events are preventable, Dr. Uejima offered that those that are preventable could typically be attributed to either the practitioner or the system.  Individual practitioner issues are often best handled by peer review.  Therefore, improvements in safety and quality might be best achieved if the focus is shifted from the practitioner towards improving systems and processes.  Understanding how to minimize the frequency and impact of these mistakes going forward is essential to improvements in safety and quality in pediatric anesthesia.

We were also reminded that all too often in clinical practice the focus tends to be on high severity-low frequency events when perhaps the emphasis should be on the low severity-high frequency events and near misses.  Expounding on Reason’s Swiss cheese model, Dr. Uejima suggested that standardizing processes could have a positive impact on process improvement down the line.  He offered several novel approaches to process improvement that simultaneously increased transparency and created accountability amongst staff.  This included using individual practitioner data to drive quality improvement.

The second presenter, Eileen Griffin, CRNA (Monroe Carell Jr. Children’s Hospital, Nashville), offered a sound review of respiratory physiology entitled “Intraoperative Respiratory Care of Premature Infants: Potential Risks and Anesthetic Considerations”.

Premature infants have complex respiratory physiology.  The development of gas exchange surfaces and surfactant production does not begin until 24 weeks gestation, ultimately limiting fetal viability.  Variations in ventilation and oxygenation of the premature infant can influence the development of bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia and cerebral palsy.  Additionally, increased FiO2 delivery can lead to retinopathy of prematurity and chronic lung disease in the premature infant.  Ms. Griffin pointed out several potential complications associated with the respiratory care of premature infants, including atelectrauma, volutrauma, and barotrauma. 

In animal studies, markers of lung injury have consistently been associated with high tidal volume regardless of pressure.  The most critical determinant of lung injury is seemingly end-inspiratory lung volume, thus the term volutrauma has largely replaced the term barotrauma.  Additional lung injury can be associated with repeated collapse and reopening of alveoli during the breathing cycle, which may be alleviated by high positive end-expiratory pressure (PEEP).  Caution should be taken, however, as high PEEP settings increase end-expiratory volume.  When a moderately high tidal volume is added to high end-expiratory volume, end-inspiratory over-distention and increased volutrauma may result.  Therefore, ventilator strategy with sufficient PEEP and low tidal volumes may be best choice in parenchymal lung disease.

The third lecture was presented by Mohamed Mahmoud, MD (Cincinnati Children’s Hospital Medical Center, Cincinnati).  Dr. Mahmoud offered a glimpse into a burgeoning field of sleep endoscopy and discussed the pros and cons of various anesthesia techniques that have been employed for sleep endoscopies.  The apnea/hypopnea index (AHI) is used to objectively rate the severity of obstructive sleep apnea (OSA) and represents the number of apneic events plus hypopneas per hour of sleep.  Scoring for adults and the pediatric patient are quite different, with a score greater than 1 leading to the diagnosis of OSA in children while a minimum score greater than 5 is required for diagnosis in the adult patient.  Various modalities, such as lateral neck x-ray, airway fluoroscopy, and Ciné CT, have been employed to identify the site of upper airway obstruction, yet flexible endoscopy and Ciné MRI remain the gold standards that guide clinical management.  Therefore, obtaining a high-quality dynamic airway imaging study is critical for accurate interpretation and subsequent medical decision-making. 

Upper airway function is dictated by airway anatomy, compliance, and collapsibility.   Providing an anesthetic that mimics natural sleep in the pediatric patient with OSA can be challenging, as continuous positive airway pressure and airway instrumentation limit the utility of imaging studies.  Propofol negatively affects sleep architecture and leads to profound inhibition of the genioglossus muscle activity resulting in upper airway collapsibility.  Dexmedetomidine has been determined to be the sedative agent of choice for dynamic upper airway evaluation, as it provides sedation without significant respiratory depression.  This ultimately produces sedative properties that parallel natural sleep.  Another viable option is the combination of dexmedetomidine and ketamine.  When delivered in unison, hemodynamic stability can be readily achieved while maintaining airway tone. 

The final lecture was presented by Elyse Parchmont, CRNA (Texas Children’s Hospital, Houston).  Ms. Parchmont reviewed the perioperative concerns when providing anesthetic care for the pediatric patient with a ventricular assist device (VAD) who is at risk for massive blood loss.  In such cases, thorough preparation is crucial.  Blood loss during the course of a redo sternotomy can be rapid and massive.  Accordingly, having appropriate blood products and femoral bypass readily available is a prerequisite prior to initiation of the surgical case.  Clinicians must possess the capacity to swiftly recognize the endpoints for volume and blood product administration, whether this is via laboratory studies or vital sign data.  For such cases, the initiation of massive transfusion protocols can stave off hemodynamic compromise.   Complications of massive blood loss and transfusion in this setting, however, can be cataclysmic.  Clinicians must therefore remain cognizant of the potential for alkalotic or acidotic shifts secondary to altered 2,3-DPG levels should older units of packed red blood cells be utilized.   Furthermore, communication with every member of the operative room team is essential to averting catastrophe.

In addition to discussing the preparation required for such cases, Ms. Parchmont reviewed the utility, contraindications, and associated complications of VAD use in the pediatric population.  The pros and cons of nine different VADs currently available for use in pediatric patients were reviewed.  The content of the lecture was summarized nicely with the presentation of a case involving a 15 year old who presented for heart transplant with a history of severe tricuspid regurgitation and mitral regurgitation, moderate to severe left atrial dilation, dilated cardiomyopathy, decreased myocardial function, congestive heat failure, and who was status post HeartMate II LVAD placement.

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