Bio

Clinical Focus


  • Anesthesia
  • Anesthesia, Pediatric
  • Anesthesia, Pediatric Cardiac

Academic Appointments


Honors & Awards


  • Medical Staff Distinguished Medical Service award, Lucille Packard Children's Hospital, Stanford (2015)

Boards, Advisory Committees, Professional Organizations


  • Board Member, Congenital Cardiac Anesthesia Society (2012 - Present)

Professional Education


  • Board Certification: Anesthesia, The Colleges of Medicine of South Africa (1984)
  • Fellowship:Childrens Hospital and Regional Medical Center Fellowships (1990) WA
  • Residency:University of Natal (1985) South Africa
  • Internship:MPILO Hospital (1977) Zimbabwe
  • Medical Education:University of Zimbabwe Medical School (1976) Zimbabwe

Research & Scholarship

Clinical Trials


  • Fibrinogen Concentrate vs Cryoprecipitate Not Recruiting

    One of the most common hemostatic derangements in pediatric open- heart surgery is an acute acquired hypofibrinogenemia. This compromises fibrin clot generation and platelet aggregation, resulting in increased bleeding and allogenic blood transfusions. Currently, fresh frozen plasma and cryoprecipitate are used to supplement fibrinogen in pediatric cardiac patients. We propose that replacing cryoprecipitate with fibrinogen concentrate will be as effective in treating post-CPB bleeding and will decrease total blood product exposure when used as part of a blood transfusion algorithm. We plan to include all patients undergoing cardiac surgery on CPB less than 12 months and a fibrinogen level <250mg/dL while on bypass. We hope to demonstrate that fibrinogen concentrate is at least as effective as the standard of care in the management of peri- operative bleeding in neonatal patients undergoing cardiopulmonary bypass. If we are able to demonstrate that fibrinogen is at least as effective as the standard of care, then we would plan a multi-center trial to demonstrate the safety and efficacy of this medication. If we are able to demonstrate that fibrinogen concentrate is effective, fibrinogen concentrate could replace allogenic products and potentially decrease transfusion related morbidity in mortality in this population.

    Stanford is currently not accepting patients for this trial. For more information, please contact Glyn D Williams, MBChB, FFA, 650-723-5728.

    View full details

Teaching

2019-20 Courses


Publications

All Publications


  • Fibrinogen Concentrate as an Alternative to Cryoprecipitate in a Postcardiopulmonary Transfusion Algorithm in Infants Undergoing Cardiac Surgery: A Prospective Randomized Controlled Trial. Anesthesia and analgesia Downey, L. A., Andrews, J., Hedlin, H., Kamra, K., McKenzie, E. D., Hanley, F. L., Williams, G. D., Guzzetta, N. A. 2019

    Abstract

    Infants undergoing cardiac surgery are at risk for bleeding and massive transfusion due to an immature coagulation system, complex surgeries, and cardiopulmonary bypass (CPB) effects. Hemodilution from CPB promotes an acquired hypofibrinogenemia that results in impaired fibrin formation, inadequate clot formation, and increased bleeding. In North America, the current standard of care to supplement fibrinogen is cryoprecipitate. An alternative option is the off-label use of fibrinogen concentrate (FC; RiaSTAP; CSL Behring, Marburg, Germany), a purified fibrinogen. Because perioperative allogenic transfusions are associated with increased morbidity and mortality, we sought to determine whether FC would be an acceptable alternative to cryoprecipitate in a post-CPB transfusion algorithm in infants undergoing open-heart surgery.We randomized 60 infants (<12 months) undergoing nonemergent cardiac surgery with CPB at 2 tertiary care children's hospitals to receive either cryoprecipitate or FC in a post-CPB transfusion algorithm. Infants underwent a stratified randomization based on institution and surgical complexity. The primary outcome was the difference in number of intraoperative allogenic blood product transfusions. Secondary outcomes included 24-hour chest tube output (CTO), mechanical ventilation time, adverse events (AEs), intensive care unit (ICU) length of stay (LOS), hospital LOS, postoperative thrombosis, and death within 30 days of surgery. The primary analysis followed the intent-to-treat (ITT) principle and was performed using linear regression adjusted for institution and complexity of surgery. A per-protocol (PP) analysis was also performed.Between June 2016 and January 2018, we enrolled 60 patients with complete data available for 25 patients who received cryoprecipitate and 29 patients who received FC. Patients in the cryoprecipitate group (median age: 4 months [2-6 months]) received 5.5 (4.0-7.0) allogeneic blood units in the ITT analysis and 6.0 units (5.0-7.0 units) in the PP analysis. Patients in the FC group (median age: 4 months [2-5]) received 4 units (3.0-5.0 units) in the ITT analysis and 4.0 units (3.0-5.0 units) in the PP analysis. In the adjusted ITT analysis, the FC group received 1.79 units (95% confidence interval [CI], 0.64-2.93; P = .003) less than the cryoprecipitate group. In the adjusted PP analysis, the FC group received 2.67 units (95% CI, 1.75-3.59; P < .001) less than the cryoprecipitate group. There were no significant differences in secondary outcomes or AEs.Our findings suggest that FC may be considered as an alternative to cryoprecipitate for the treatment of hypofibrinogenemia in infants with bleeding after CPB. Although we found no significant differences between secondary outcomes or AEs, further studies are needed to assess safety.

    View details for DOI 10.1213/ANE.0000000000004384

    View details for PubMedID 31490252

  • Epoprostenol Therapy for a Pediatric Patient With Subacute Heparin-Induced Thrombocytopenia and a Ventricular Assist Device Undergoing Heart Transplant: A Case Report A & A PRACTICE Navaratnam, M., Williams, G. D., Shuttleworth, P., Almond, C., Maeda, K. 2018; 11 (12): 329?31

    Abstract

    Concerns remain regarding the use of direct thrombin inhibitors for cardiopulmonary bypass anticoagulation in pediatric patients with heparin-induced thrombocytopenia undergoing complex cardiac surgery. We describe the safe and effective use of epoprostenol sodium as an alternative therapy before heparin exposure for a pediatric patient with subacute heparin-induced thrombocytopenia and a ventricular assist device undergoing heart transplant.

    View details for PubMedID 29985837

  • Reporting of Perioperative Adverse Events by Pediatric Anesthesiologists at a Tertiary Children's Hospital: Targeted Interventions to Increase the Rate of Reporting. Anesthesia and analgesia Williams, G. D., Muffly, M. K., Mendoza, J. M., Wixson, N., Leong, K., Claure, R. E. 2017

    Abstract

    Incident reporting systems (IRSs) are important patient safety tools for identifying risks and opportunities for improvement. A major IRS limitation is underreporting of incidents. Perioperative anesthesia IRSs have been established at multiple pediatric institutions and a national pediatric anesthesia IRS for perioperative serious adverse events (SAEs) is maintained by Wake Up Safe (WUS), a patient safety organization dedicated to pediatric anesthesia quality improvement. A confidential, electronic, perioperative IRS was instituted at our tertiary children's hospital, which is a WUS member. The primary study aim was to increase the rate of incident reporting by anesthesiologists at our institution through a series of interventions. The secondary aim was to characterize our reporting behavior relative to national practice by referencing SAE data from WUS.Perioperative adverse events reported over a 71-month period (November 2010 to September 2016) were categorized and the monthly reporting rates determined. Effects of 6 interventions targeted to increase the reporting rate were analyzed using control charts. Intervention 5 involved interviewing pediatric anesthesiologists to ascertain incident reporting barriers and motivators. A key driver diagram was developed and used to guide an improvement initiative. Incidents that fulfilled WUS criteria for SAEs were identified and categorized. SAE reporting rates over a 27-month period for 12 WUS member institutions were determined.2689 perioperative adverse events were noted in 1980 of 72,384 anesthetics. Mean monthly adverse event case rate was 273 (95% confidence interval, 250-297) per 10,000 anesthetics. A subgroup involving 54,469 cases had 529 SAEs in 440 anesthetics; a mean monthly SAE case rate of 80 (95% confidence interval, 69-91) per 10,000 anesthetics. Cardiac, respiratory, and airway events predominated. Relative to WUS peer members, our institution is a high-reporting outlier. The rate of incident reporting per 10,000 anesthetics was sustainably increased from 149 35 to 387 73 (mean SD) after implementing mandatory IRS data entry and Intervention 5 quality improvement initiative. Barriers to reporting included concern for punitive repercussions, feelings of incompetence, poor education about what constitutes an event, lack of feedback, and the perception that reporting had no value. These were addressed by IRS education, cultivation of a culture of safety where reporting is encouraged, reporter feedback, and better inclusion of anesthesiologists in patient safety work.Electronic mandatory IRS data entry and an initiative to understand and address reporting barriers and motivators were associated with sustained increases in the adverse event reporting rate. These strategies to minimize underreporting enhance IRS value for learning and may be generalizable.

    View details for PubMedID 28678071

  • Current use of factor concentrates in pediatric cardiac anesthesia. Paediatric anaesthesia Guzzetta, N. A., Williams, G. D. 2017; 27 (7): 678?87

    Abstract

    Excessive bleeding following pediatric cardiopulmonary bypass is associated with increased morbidity and mortality, both from the effects of hemorrhage and the therapies employed to achieve hemostasis. Neonates and infants are especially at risk because their coagulation systems are immature, surgeries are often complex, and cardiopulmonary bypass technologies are inappropriately matched to patient size and physiology. Consequently, these young children receive substantial amounts of adult-derived blood products to restore adequate hemostasis. Adult and pediatric data demonstrate associations between blood product transfusions and adverse patient outcomes. Thus, efforts to limit bleeding after pediatric cardiopulmonary bypass and minimize allogeneic blood product exposure are warranted. The off-label use of factor concentrates, such as fibrinogen concentrate, recombinant activated factor VII, and prothrombin complex concentrates, is increasing as these hemostatic agents appear to offer several advantages over conventional blood products. However, recognizing that these agents have the potential for both benefit and harm, well-designed studies are needed to enhance our knowledge and to determine the optimal use of these agents. In this review, our primary objective was to examine the evidence regarding the use of factor concentrates to treat bleeding after pediatric CPB and identify where further research is required. PubMed, MEDLINE/OVID, The Cochrane Library and the Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched to identify existing studies.

    View details for PubMedID 28393462

  • Perioperative management of pediatric en-bloc combined heart-liver transplants: a case series review. Paediatric anaesthesia Navaratnam, M., Ng, A., Williams, G. D., Maeda, K., Mendoza, J. M., Concepcion, W., Hollander, S. A., Ramamoorthy, C. 2016; 26 (10): 976-986

    Abstract

    Combined heart and liver transplantation (CHLT) in the pediatric population involves a complex group of patients, many of whom have palliated congenital heart disease (CHD) involving single ventricle physiology.The purpose of this study was to describe the perioperative management of pediatric patients undergoing CHLT at a single institution and to identify management strategies that may be used to optimize perioperative care.We did a retrospective database review of all patients receiving CHLT at a children's hospital between 2006 and 2014. Information collected included preoperative characteristics, intraoperative management, blood transfusions, and postoperative morbidity and mortality.Five pediatric CHLTs were performed over an 8-year period. All patients had a history of complex CHD with multiple sternotomies, three of whom had failing Fontan physiology. Patient age ranged from 7 to 23 years and weight from 29.5 to 68.5 kg. All CHLTs were performed using an en-bloc technique where both the donor heart and liver were implanted together on cardiopulmonary bypass (CPB). The median operating room time was 14.25 h, median CPB time was 3.58 h, and median donor ischemia time was 4.13 h. Patients separated from CPB on dopamine, epinephrine, and milrinone infusions and two required inhaled nitric oxide. All patients received a massive intraoperative blood transfusion post CPB with amounts ranging from one to three times the patient's estimated blood volume. The patient who required the most transfusions was in decompensated heart and liver failure preoperatively. Four of the five patients received an antifibrinolytic agent as well as a procoagulant (prothrombin complex concentrate or recombinant activated Factor VII) to assist with hemostasis. There were no 30-day thromboembolic events detected. Postoperatively the median length of mechanical ventilation, ICU stay and stay to hospital discharge was 4, 8, and 37 days, respectively. All patients are alive and free from allograft rejection at this time.Combined heart and liver transplantation in the pediatric population involves a complex group of patients with unique perioperative challenges. Successful management starts with thorough preoperative planning and communication and involves strategies to deal with massive intraoperative hemorrhage and coagulopathy in addition to protecting and supporting the transplanted heart and liver and meticulous surgical technique. An integrated multidisciplinary team approach is the cornerstone for successful outcomes.

    View details for DOI 10.1111/pan.12950

    View details for PubMedID 27402424

  • Anesthesia for Placement of a Paracorporeal Lung Assist Device and Subsequent Heart-Lung Transplantation in a Child with Suprasystemic Pulmonary Hypertension and End-Stage Respiratory Failure. A & A case reports Char, D. S., Yarlagadda, V., Maeda, K., Williams, G. 2016; 6 (10): 308-310

    Abstract

    Pediatric patients with end-stage respiratory failure and pulmonary hypertension traditionally have poor outcomes when bridged with extracorporeal membrane oxygenation to lung or heart-lung transplantation. Therefore, several institutions have attempted paracorporeal lung assist devices as a bridge. However, given the small number of patients, little is known about approaches to anesthetic induction in these hemodynamically unstable patients either before placement of a device or anesthetic induction once a device is in situ. In this case report, we describe our anesthetic experience managing a 13-year-old boy for both paracorporeal lung assist device placement and subsequent heart-lung transplantation.

    View details for DOI 10.1213/XAA.0000000000000300

    View details for PubMedID 27002753

  • Editorial comment on paper by Naguib, et al. 'A single-center strategy to minimize blood transfusion in neonates and children undergoing cardiac surgery'. Paediatric anaesthesia Williams, G. D., Ramamoorthy, C. 2015; 25 (5): 442-444

    View details for DOI 10.1111/pan.12653

    View details for PubMedID 25851520

  • Knowledge and Attitudes of Anesthesia Providers about Noncardiac Surgery in Adults with Congenital Heart Disease CONGENITAL HEART DISEASE Maxwell, B. G., Williams, G. D., Ramamoorthy, C. 2014; 9 (1): 45-53

    Abstract

    OBJECTIVE: To examine the knowledge and attitudes of anesthesia providers in relation to the care of adult congenital heart disease (ACHD) patients presenting for noncardiac surgery. DESIGN/SETTING: A novel survey was designed and administered to 168 anesthesiologists across a single academic department in a range of practice environments. INTERVENTIONS: None. OUTCOME MEASURES: Survey responses, including true/false, multiple choice, and Likert scale questions. RESULTS: A total of 118 anesthesiologists (response rate = 70%) completed the survey. Knowledge scores ranged from 0 to 19 (median [interquartile range] = 7 [5-13]) out of a possible maximum of 20. Total knowledge scores differed significantly by fellowship background (P = .004), with higher scores in those with cardiac (11 [7-15], P = .005) and pediatric (12 [6-15], P = .001) fellowship training, but not in those with critical care, obstetric, regional, or pain management training. Scores also differed by frequency of providing care for cardiopulmonary bypass cases and frequency of providing care for patients under 2 years of age (P < .001 for both), but not by gender or years removed from residency. Respondents reported only moderate levels of comfort with a range of questions about providing perioperative or obstetric care to ACHD patients, with decreasing levels of comfort reported in patients with more complex lesions. CONCLUSIONS: Within the context of the limitations of a single-institution survey design, the low levels of knowledge and comfort we observed suggest that providers may benefit from improved training and protocols for ensuring adequate preparedness for the care of ACHD patients.

    View details for DOI 10.1111/chd.12076

    View details for Web of Science ID 000329916300016

    View details for PubMedID 23648140

  • Administration of ketamine to children with pulmonary hypertension is safe: pro-con debate PRO ARGUMENT PEDIATRIC ANESTHESIA Williams, G. D. 2012; 22 (11): 1042-1052

    View details for DOI 10.1111/pan.12033

    View details for Web of Science ID 000310802400002

  • Case report: airway and concurrent hemodynamic management in a neonate with oculo-auriculo-vertebral (Goldenhar) syndrome, severe cervical scoliosis, interrupted aortic arch, multiple ventricular septal defects, and an unstable cervical spine PEDIATRIC ANESTHESIA Char, D. S., Gipp, M., Boltz, M. G., Williams, G. D. 2012; 22 (9): 932-934

    Abstract

    We report the challenging case of a 1-week-old, term, 2.4 kg neonate with Goldenhar syndrome (including microcephaly, left microtia, left facial palsy, dextro-scoliosis of the cervical spine, and cervico-thoracic levoscoliosis), multiple ventricular septal defects, a type B interrupted aortic arch, a large patent ductus arteriosis, and radiographic and clinical signs concerning for an unstable cervical spine. Our anesthesia team was consulted for perioperative management of this patient during her surgical repair. This case report describes the use of the Air-Q size 1 laryngeal airway (LA) to assist fiberoptic intubation in an ASA 4 neonate with cardiac disease, an anticipated difficult airway with the addition of an unstable cervical spine, as well as the anesthetic techniques used to maintain hemodynamic stability while the airway was secured.

    View details for DOI 10.1111/j.1460-9592.2012.03915.x

    View details for Web of Science ID 000306900400017

    View details for PubMedID 22834469

  • Administration of ketamine to children with pulmonary hypertension is safe: pro-con debate: Pro Argument. Paediatric anaesthesia Williams, G. D., Friesen, R. H. 2012; 22 (11): 1042?52

    View details for PubMedID 25631695

  • Cardiomyopathy in childhood CURRENT OPINION IN ANESTHESIOLOGY Williams, G. D., Hammer, G. B. 2011; 24 (3): 289-300

    Abstract

    Cardiomyopathy is an important cause of heart failure and a major indication for heart transplantation in children. Unfortunately, there is a paucity of literature to guide the anesthesiologist who cares for these high-risk children. This review describes the cardiomyopathy phenotypes that occur in children and the factors that are associated with clinical outcomes and perioperative complications. Anesthesia considerations will be reviewed.During the past decade, there has been a dramatic increase in knowledge related to cardiomyopathy. New genotypes and phenotypes are recognized and new therapies have been devised. Multicenter pediatric cardiomyopathy registries are obtaining data essential for enhanced understanding of the disease.The diverse spectrum and complexity of pediatric cardiomyopathies mandate a thorough appreciation of the cardiac pathophysiology pertinent to an individual child's perioperative management. Important issues include multisystem disease associated with syndromic or genetic disorders, appropriate preoperative patient assessment to adequately characterize patient risk and guide therapy, and intraoperative and postoperative care plans that target optimal outcomes.

    View details for DOI 10.1097/ACO.0b013e3283462257

    View details for PubMedID 21478741

  • Perioperative management of low birth weight infants for open-heart surgery PEDIATRIC ANESTHESIA Williams, G. D., Cohen, R. S. 2011; 21 (5): 538-553

    Abstract

    Infants of birth weight ?2500 g are termed low birth weight (LBW). These children often have considerable morbidity from prematurity and intra-uterine growth restriction. Additionally, LBW infants have increased risk for cardiac and noncardiac congenital anomalies and may require surgery. Primary rather than palliative surgical repair of cardiac lesions has been preferred in recent years. However, LBW remains a risk factor for increased mortality and morbidity after open-heart surgery (OHS). There is a paucity of information about the anesthetic challenges presented by LBW infants undergoing OHS. This review summarizes the perioperative issues of relevance to anesthesiologists who manage these high-risk patients. Emphasis is placed on management concerns that are unique to LBW infants. Retrospective data from the authors' institution are provided for those aspects of anesthetic care that lack published studies. Successful outcome often requires substantial hospital resources and collaborative multi-disciplinary effort.

    View details for DOI 10.1111/j.1460-9592.2011.03529.x

    View details for PubMedID 21306474

  • Heterotaxy Syndrome: Implications for Anesthesia Management JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Williams, G. D., Feng, A. 2010; 24 (5): 834-844

    View details for DOI 10.1053/j.jvca.2010.02.012

    View details for Web of Science ID 000282669200020

    View details for PubMedID 20421166

  • Undiagnosed Type IIIc Gaucher Disease in a Child With Aortic and Mitral Valve Calcification: Perioperative Complications After Cardiac Surgery JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Mireles, S. A., Seybold, J., Williams, G. 2010; 24 (3): 471-474

    View details for DOI 10.1053/j.jvca.2009.05.006

    View details for Web of Science ID 000278288500017

    View details for PubMedID 19632857

  • Perioperative complications in children with pulmonary hypertension undergoing general anesthesia with ketamine PEDIATRIC ANESTHESIA Williams, G. D., Maan, H., Ramamoorthy, C., Kamra, K., Bratton, S. L., Bair, E., Kuan, C. C., Hammer, G. B., Feinstein, J. A. 2010; 20 (1): 28-37

    Abstract

    Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications in children, including pulmonary hypertensive crisis and cardiac arrest. Uncertainty remains about the safety of ketamine anesthesia in this patient population.Retrospectively review the medical records of children with PAH to ascertain the nature and frequency of peri-procedural complications and to determine whether ketamine administration was associated with peri-procedural complications.Children with PAH (mean pulmonary artery pressure > or =25 mmHg and pulmonary vascular resistance index > or =3 Wood units) who underwent general anesthesia for procedures during a 6-year period (2002-2008) were enrolled. Details about the patient, PAH, procedure, anesthetic and postprocedural course were noted, including adverse events during or within 48 h of the procedure. Complication rates were reported per procedure. Association between ketamine and peri-procedural complications was tested.Sixty-eight children (median age 7.3 year, median weight 22 kg) underwent 192 procedures. Severity of PAH was mild (23%), moderate (37%), and severe (40%). Procedures undertaken were major surgery (n = 20), minor surgery (n = 27), cardiac catheterization (n = 128) and nonsurgical procedures (n = 17). Ketamine was administered during 149 procedures. Twenty minor and nine major complications were noted. Incidence of cardiac arrest was 0.78% for cardiac catheterization procedures, 10% for major surgical procedures and 1.6% for all procedures. There was no procedure-related mortality. Ketamine administration was not associated with increased complications.Ketamine appears to be a safe anesthetic option for children with PAH. We report rates for cardiopulmonary resuscitation and mortality that are more favorable than those previously reported.

    View details for DOI 10.1111/j.1460-9592.2009.03166.x

    View details for PubMedID 20078799

  • A randomized, controlled trial of aprotinin in neonates undergoing open-heart surgery PEDIATRIC ANESTHESIA Williams, G. D., Ramamoorthy, C., Pentcheva, K., Boltz, M. G., Kamra, K., Reddy, V. M. 2008; 18 (9): 812-819

    Abstract

    Neonates undergoing open-heart surgery are especially at risk for massive bleeding and pronounced inflammation. The efficacy of aprotinin, a serine protease inhibitor, at ameliorating these adverse effects of cardiopulmonary bypass has not been clearly demonstrated in neonates.Term neonates were enrolled and randomly assigned in a blinded fashion to receive saline (group P, placebo) or high-dose aprotinin (group A). Intraoperative management was standardized: surgeon, anesthesia, cardiopulmonary bypass and hemostasis therapy. Patients were admitted postoperatively to a pediatric cardiac intensive care unit. Primary outcome measure of efficacy was duration of the postoperative mechanical ventilation. Secondary outcome measures were total volume and units of blood products transfused intraoperatively and for 24 h after surgery, duration of chest tube in situ, and intensive care and hospital stays after surgery.Twenty-six neonates were enrolled; 13 received aprotinin and 13 received placebo. The study was halted prematurely because of US Food and Drug Administration's concerns about aprotinin's safety. Baseline patient, surgery and cardiopulmonary bypass characteristics were similar between groups. No outcome variables differed between groups (P > 0.05). Duration of postoperative ventilation was 115 +/- 139 h (group A); 126 +/- 82 h (group P); P = 0.29, and total blood product exposure was 8.2 +/- 2.6 U (group A); 8.8 +/- 1.4 U (group P); P = 0.1. Postoperative blood creatinine values did not differ between groups. In-hospital mortality rate was 4%.Aprotinin was not shown to be efficacious in neonates undergoing open-heart surgery. It is unclear whether adult aprotinin safety data are relevant to neonates undergoing open-heart surgery.

    View details for DOI 10.1111/j.1460-9592.2008.02678.x

    View details for Web of Science ID 000257990900002

    View details for PubMedID 18768040

  • Anesthetic management of children with pulmonary arterial hypertension PEDIATRIC ANESTHESIA Friesen, R. H., Williams, G. D. 2008; 18 (3): 208-216

    Abstract

    Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications, including pulmonary hypertensive crisis and cardiac arrest. Several mechanisms of hemodynamic deterioration, including acute increases in pulmonary vascular resistance (PVR), alterations of ventricular contractility and function and coronary hypoperfusion can contribute to morbidity. Anesthetic drugs exert a variety of effects on PVR, some of which are beneficial and some undesirable. The goals of balanced and cautious anesthetic management are to provide adequate anesthesia and analgesia for the surgical procedure while minimizing increases in PVR and depression of myocardial function. The development of specific pulmonary vasodilators has led to significant advances in medical therapy of PAH that can be incorporated in anesthetic management. It is important that anesthesiologists caring for children with PAH be aware of the increased risk, understand the pathophysiology of PAH, form an appropriate anesthetic management plan and be prepared to treat a pulmonary hypertensive crisis.

    View details for DOI 10.1111/j.1460-9592.2008.02419.x

    View details for Web of Science ID 000253313200003

    View details for PubMedID 18230063

  • The effects of dexmedetomidine on cardiac electrophysiology in children ANESTHESIA AND ANALGESIA Hammer, G. B., Drover, D. R., Cao, H., Jackson, E., Williams, G. D., Ramamoorthy, C., Van Hare, G. F., Niksch, A., Dubin, A. M. 2008; 106 (1): 79-83

    Abstract

    Dexmedetomidine (DEX) is an alpha2-adrenergic agonist that is approved by the Food and Drug Administration for short-term (<24 h) sedation in adults. It is not approved for use in children. Nevertheless, the use of DEX for sedation and anesthesia in infants and children appears to be increasing. There are some concerns regarding the hemodynamic effects of the drug, including bradycardia, hypertension, and hypotension. No data regarding the effects of DEX on the cardiac conduction system are available. We therefore aimed to characterize the effects of DEX on cardiac conduction in pediatric patients.Twelve children between the ages of 5 and 17 yr undergoing electrophysiology study and ablation of supraventricular accessory pathways had hemodynamic and cardiac electrophysiologic variables measured before and during administration of DEX (1 microg/kg IV over 10 min followed by a 10-min continuous infusion of 0.7 microg x kg(-1) x h(-1)).Heart rate decreased while arterial blood pressure increased significantly after DEX administration. Sinus node function was significantly affected, as evidenced by an increase in sinus cycle length and sinus node recovery time. Atrioventricular nodal function was also depressed, as evidenced by Wenckeback cycle length prolongation and prolongation of PR interval.DEX significantly depressed sinus and atrioventricular nodal function in pediatric patients. Heart rate decreased and arterial blood pressure increased during administration of DEX. The use of DEX may not be desirable during electrophysiology study and may be associated with adverse effects in patients at risk for bradycardia or atrioventricular nodal block.

    View details for DOI 10.1213/01.ane.0000297421.92857.4e

    View details for PubMedID 18165557

  • Use of recombinant activated factor VII in children PEDIATRIC ANESTHESIA Hammer, G. B., Williams, G. D. 2007; 17 (12): 1123-1125
  • Ketamine does not increase pulmonary vascular resistance in children with pulmonary hypertension undergoing sevoflurane anesthesia and spontaneous ventilation ANESTHESIA AND ANALGESIA Williams, G. D., Philip, B. M., Chu, L. F., Boltz, M. G., Kamra, K., Terwey, H., Hammer, G. B., Perry, S. B., Feinstein, J. A., Ramamoorthy, C. 2007; 105 (6): 1578-1584

    Abstract

    The use of ketamine in children with increased pulmonary vascular resistance is controversial. In this prospective, open label study, we evaluated the hemodynamic responses to ketamine in children with pulmonary hypertension (mean pulmonary artery pressure >25 mm Hg).Children aged 3 mo to 18 yr with pulmonary hypertension, who were scheduled for cardiac catheterization with general anesthesia, were studied. Patients were anesthetized with sevoflurane (1 minimum alveolar anesthetic concentration [MAC]) in air while breathing spontaneously via a facemask. After baseline catheterization measurements, sevoflurane was reduced (0.5 MAC) and ketamine (2 mg/kg IV over 5 min) was administered, followed by a ketamine infusion (10 microg x kg(-1) x min(-1)). Catheterization measurements were repeated at 5, 10, and 15 min after completion of ketamine load. Data at various time points were compared (ANOVA, P < 0.05).Fifteen patients (age 147, 108 mo; median, interquartile range) were studied. Diagnoses included idiopathic pulmonary arterial hypertension (5), congenital heart disease (9), and diaphragmatic hernia (1). At baseline, median (interquartile range) baseline pulmonary vascular resistance index was 11.3 (8.2) Wood units; 33% of patients had suprasystemic mean pulmonary artery pressures. Heart rate (99, 94 bpm; P = 0.016) and Pao2 (95, 104 mm Hg; P = 007) changed after ketamine administration (baseline, 15 min after ketamine; P value). There were no significant differences in mean systemic arterial blood pressure, mean pulmonary artery pressure, systemic or pulmonary vascular resistance index, cardiac index, arterial pH, or Paco2.In the presence of sevoflurane, ketamine did not increase pulmonary vascular resistance in spontaneously breathing children with severe pulmonary hypertension.

    View details for DOI 10.1213/01.ane.0000287656.29064.89

    View details for PubMedID 18042853

  • Children with cardiomyopathy: complications after noncardiac procedures with general anesthesia PEDIATRIC ANESTHESIA Kipps, A. K., Ramamoorthy, C., Rosenthal, D. N., Williams, G. D. 2007; 17 (8): 775-781

    Abstract

    Children with cardiomyopathy (CM) often undergo procedures that require general anesthesia (GA) but little is known about anesthesia-related adverse events or postprocedural outcomes.After approval, all children with CM who underwent nonopen heart surgical procedures and/or diagnostic imaging under GA at a tertiary children's hospital during January 2002 to May 2005 were identified from a clinical database. Based on their preprocedure fractional shortening (FS) on echocardiogram, systemic ventricular dysfunction was categorized as mild (FS 23-28%), moderate (FS 16-22%), or severe (FS < 16%) and those with normal (FS > 28%) were excluded from review.Twenty-six patients underwent 34 procedures under GA, of whom 13 (38%) had mild or moderate ventricular dysfunction and 21 (62%) had severe dysfunction. Common procedures included pacer/defibrillator placement (43%) and imaging studies (18%). Eighteen complications were noted in 12 patients. Fifteen (83%) complications occurred in patients with severe ventricular dysfunction. One patient with severe ventricular dysfunction died (3% mortality). Hypotension requiring inotropic support was the most frequent complication (61%). Children with severe ventricular dysfunction often required hospital support pre- and postprocedure with 67% requiring intensive care. Hospital stay was longer for patients with severe ventricular dysfunction compared with children with mild or moderate ventricular dysfunction (P = 0.006).The 30-day mortality rate was low but complications were common, especially in patients with severe ventricular dysfunction. For these patients, we recommend early consideration of perioperative intensive care support to optimize cardiovascular therapy and monitoring.

    View details for DOI 10.1111/j.1460-9592.2007.02245.x

    View details for Web of Science ID 000247582600007

    View details for PubMedID 17596222

  • Brain monitoring and protection during pediatric cardiac surgery. Seminars in cardiothoracic and vascular anesthesia Williams, G. D., Ramamoorthy, C. 2007; 11 (1): 23-33

    Abstract

    With advances in medical care, survival after cardiac surgery for congenital heart disease has dramatically improved, and attention is increasingly focused on long-term functional morbidities, especially neurodevelopmental outcomes, with their profound consequences to patients and society. There are multiple reasons for concern about brain injury. Some cardiac defects are associated with brain anomalies and altered cerebral blood flow regulation. Brain imaging studies have demonstrated that injury to gray and white matter is quite frequent before heart surgery in neonates. Cardiopulmonary bypass and deep hypothermic circulatory arrest are associated with short- and longer-term adverse neurologic outcome. Additional brain injury can occur during the patient's recovery from surgery. Strategies to optimize neurologic outcome continue to evolve. With new technological developments, perioperative neurologic monitoring of small children has become easier, and data suggest these modalities usefully identify adverse neurologic events and might predict outcome. Monitoring methods to be discussed include processed electroencephalography, near infrared spectroscopy, and transcranial Doppler ultrasound. Alternative perfusion techniques to deep hypothermic circulatory arrest have been developed, such as regional antegrade cerebral perfusion during cardiopulmonary bypass. Other neuroprotective strategies employed during open-heart surgery include temperature regulation, acid-base management, degree of hemodilution, blood glucose control and anti-inflammatory therapies. Evidence of the impact of these measures on neurologic outcome is examined, and deficiencies in our current understanding of neurologic function in children with congenital heart disease are identified.

    View details for PubMedID 17484171

  • Modified and conventional ultrafiltration during pediatric cardiac surgery: Clinical outcomes compared JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Williams, G. D., Ramamoorthy, C., Chu, L., Hammer, G. B., Kamra, K., Boltz, M. G., Pentcheva, K., McCarthy, J. P., Reddy, V. M. 2006; 132 (6): 1291-1298

    Abstract

    This prospective study compared clinical outcomes after heart surgery between three groups of infants with congenital heart disease. One group received dilutional conventional ultrafiltration (group D), another received modified ultrafiltration (group M), and a third group received both dilutional conventional and modified ultrafiltration (group B). We hypothesized that group B patients would have the best clinical outcome.Children younger than 1 year undergoing heart surgery for biventricular repair by the same surgeon were randomly allocated to one of the three study groups. Patient management was standardized, and intensive care staff were blinded to group allocation. Primary outcome measure was duration of postoperative mechanical ventilation. Other outcome measures recorded included total blood products transfused, duration of chest tube in situ, chest tube output, and stays in intensive care and in the hospital.Sixty infants completed study protocol. Mean age and weight were as follows: group D (n = 19), 61 days, 4.3 kg; group M (n = 20), 64 days, 4.5 kg; and group B (n = 21), 86 days, 4.4 kg. Preoperative and intraoperative characteristics were similar between groups. Ultrafiltrate volumes obtained were 196 +/- 93 mL/kg in group D, 105 +/- 33 mL/kg in group M, and 261 +/- 113 mL/kg in group B. There were no significant differences between groups for any outcome variable. Technical difficulties prevented completion of modified ultrafiltration in 2 of 41 infants.There was no clinical advantage in combining conventional and modified ultrafiltration. Because clinical outcomes were similar across groups, relative risks of the ultrafiltration strategies may influence choice.

    View details for DOI 10.1016/j.jtcvs.2006.05.059

    View details for PubMedID 17140945

  • Anesthesia considerations for pediatric thoracic solid organ transplant. Anesthesiology clinics of North America Williams, G. D., Ramamoorthy, C. 2005; 23 (4): 709-?

    Abstract

    This article discusses the indications, perioperative management, postoperative complications, and patient outcome of pediatric heart transplantation and pediatric lung transplantation. Special emphasis is placed on the anesthetic considerations relevant for children who are undergoing or have received a solid thoracic organ transplant.

    View details for PubMedID 16310660

  • Postoperative analgesia after spinal blockade in infants and children undergoing cardiac surgery ANESTHESIA AND ANALGESIA Hammer, G. B., Ramamoorthy, C., Cao, H., Williams, G. D., Boltz, M. G., Kamra, K., Drover, D. R. 2005; 100 (5): 1283-1288

    Abstract

    The aim of this prospective, randomized, controlled clinical trial was to define the opioid analgesic requirement after a remifentanil (REMI)-based anesthetic with spinal anesthetic blockade (SAB+REMI) or without (REMI) spinal blockade for open-heart surgery in children. We enrolled 45 patients who were candidates for tracheal extubation in the operating room after cardiac surgery. Exclusion criteria included age <3 mo and >6 yr, pulmonary hypertension, congestive heart failure, contraindication to SAB, and failure to obtain informed consent. All patients had an inhaled induction with sevoflurane and maintenance of anesthesia with REMI and isoflurane (0.3% end-tidal). In addition, patients assigned to the SAB+REMI group received SAB with tetracaine (0.5-2.0 mg/kg) and morphine (7 mug/kg). After tracheal extubation in the operating room, patients received fentanyl 0.3 mug/kg IV every 10 min by patient-controlled analgesia for pain score = 4. Pain scores and fentanyl doses were recorded every hour for 24 h or until the patient was ready for discharge from the intensive care unit. Patients in the SAB+REMI group had significantly lower pain scores (P = 0.046 for the first 8 h; P =0.05 for 24 h) and received less IV fentanyl (P = 0.003 for the first 8 h; P = 0.004 for 24 h) than those in the REMI group. There were no intergroup differences in adverse effects, including hypotension, bradycardia, highest PaCO(2), lowest pH, episodes of oxygen desaturation, pruritus, and vomiting.

    View details for DOI 10.1213/01.ANE.0000148698.84881.10

    View details for PubMedID 15845670

  • Abnormal coagulation during pediatric craniofacial surgery PEDIATRIC NEUROSURGERY Williams, G. D., Ellenbogen, R. G., Gruss, J. S. 2001; 35 (1): 5-12

    Abstract

    This prospective study of children undergoing major craniofacial surgery was undertaken to determine whether abnormal hemostasis occurred and to characterize any coagulopathy found.Coagulation tests, blood loss and blood product transfusions were recorded perioperatively. Packed red blood cells (PRBC) were transfused to maintain target hematocrit. Patients with blood loss >100 ml/kg (group A, n = 5) were compared to patients with blood loss <100 ml/kg (group B, n = 22) using Mann-Whitney U test (p < 0.05).Twenty-seven children (age range 2.9--27.9 months) had median total blood loss of 64 ml/kg. At completion of surgery, median coagulation values differed significantly between groups for prothrombin time (A: 16.6 s; B: 13.8 s), partial thromboplastin time (A: 44 s; B: 29 s), thrombin time (A: 28 s; B: 23 s), thromboelastograph reaction time (A: 7 mm; B: 4 mm), prothrombin fragment F1.2 (A: 1.9 nmol/l; B: 3.3 nmol/l) and platelet count (A: 174 K/mm(-3); B: 239 K/mm(-3)). Fibrinolysis was not associated with blood loss. Median units transfused were in group A 3 units and group B 1 unit (p = 0.001). All patients received PRBC transfusions but only group A patients received other blood products (fresh frozen plasma, platelets).Children transfused with PRBC during craniosynostosis repair can become coagulopathic from coagulation factor depletion when hemorrhage approaches 1.5 times estimated blood volume.

    View details for Web of Science ID 000170423500002

    View details for PubMedID 11490184

  • Con: The routine use of aprotinin during pediatric cardiac surgery is not a benefit JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Williams, G. D., Ramamoorthy, C. 1999; 13 (6): 785-788

    View details for Web of Science ID 000084306700023

    View details for PubMedID 10622666

  • Coagulation tests during cardiopulmonary bypass correlate with blood loss in children undergoing cardiac surgery JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Williams, G. D., Bratton, S. L., Riley, E. C., Ramamoorthy, C. 1999; 13 (4): 398-404

    Abstract

    To examine whether coagulation tests, sampled before and during cardiopulmonary bypass (CPB), are related to blood loss and blood product transfusion requirements, and to determine what test value(s) provide the best sensitivity and specificity for prediction of excessive hemorrhage.Prospective.University-affiliated, pediatric medical center.Four hundred ninety-four children.Coagulation tests.Demographic, coagulation test, blood loss, and transfusion data were noted in consecutive children undergoing cardiac surgery. Laboratory tests included hematocrit (Hct), prothrombin time, partial thromboplastin time (PTT), platelet count, fibrinogen concentration, and thromboelastography. Stepwise linear regression analysis indicated that platelet count during CPB was the variable most significantly associated with intraoperative blood loss (in milliliters per kilogram) and 12-hour chest tube output (in milliliters per kilogram). Other independent variables associated with blood loss were thromboelastography maximum amplitude (MA) during CPB, preoperative PTT, preoperative Hct, and preoperative thromboelastography angle and shear modulus values. Thromboelastography MA during CPB was the only variable associated with total products transfused (in milliliters per kilogram). Of all tests studied, platelet count during CPB (< or = 108,000/microL) provided the maximum sensitivity (83%) and specificity (58%) for prediction of excessive blood loss (receiver operating characteristic analysis). Blood loss was inversely related to patient age; neonates received the most donor units (median, 8 units; range, 6 to 10 units).During cardiac surgery, coagulation tests (including thromboelastography) drawn pre-CPB and during CPB are useful to identify children at risk for excessive bleeding. Platelet count during CPB was the variable most significantly associated with blood loss.

    View details for Web of Science ID 000082042400005

    View details for PubMedID 10468251

  • Factors associated with blood loss and blood product transfusions: A multivariate analysis in children after open-heart surgery ANESTHESIA AND ANALGESIA Williams, G. D., Bratton, S. L., Ramamoorthy, C. 1999; 89 (1): 57-64

    Abstract

    In this prospective cohort study of 548 children undergoing open-heart surgery, we evaluated demographic and perioperative factors to identify variables associated with perioperative blood loss and blood product transfusions. Using multivariate analysis, younger patient age was found to be the variable most significantly associated with bleeding and transfusions. Higher preoperative hematocrit, complex surgery, lower platelet count during cardiopulmonary bypass (CPB), and longer duration of deep hypothermic circulatory arrest were also significantly associated with bleeding and transfusion. Excessive postoperative chest tube (CT) drainage was associated with intraoperative bleeding. Independently associated variables accounted for 76% of the variability in CT output measured after 2 h in intensive care. Patients were subdivided into children aged < or =1 yr (infants) and children >1 yr; infants bled more intraoperatively (P<0.005); had greater cumulative CT output at 2, 6, 12, and 24 h (P<0.0001); and received more blood products (P<0.0001). Factors associated with bleeding and transfusions varied with patient age. Lower body core temperature during CPB was highly associated with blood loss and transfusions in infants, whereas resternotomy, preoperative congestive heart failure, and prolonged duration of CPB were significant factors associated with bleeding and transfusions in children >1 yr old.Knowledge of the factors associated with blood loss and blood product transfusions can help to identify children at risk of excessive bleeding after open-heart surgery.

    View details for Web of Science ID 000081101100011

    View details for PubMedID 10389779

  • Efficacy of epsilon-aminocaproic acid in children undergoing cardiac surgery JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Williams, G. D., Bratton, S. L., Riley, E. C., Ramamoorthy, C. 1999; 13 (3): 304-308

    Abstract

    To compare coagulation test results, blood loss, and blood product transfusions between patients receiving prophylactic epsilon-aminocaproic acid (EACA) and a control group matched for age, resternotomy, and surgery in children undergoing cardiac surgery.Nested case-control study.University-affiliated, pediatric medical center.Same study period; 70 patients in EACA group and 70 patients in control group.Prophylactic EACA administered intravenously (load, 150 mg/kg, infusion; 30 mg/kg/h) to 70 patients at increased risk for bleeding (reoperation or Ross procedure).Coagulation test values were measured before, during, and after cardiopulmonary bypass (CPB). Intraoperative blood loss, postoperative chest tube output, and allogenic blood product transfusions were recorded. Comparison of demographic and surgical data indicated close matching of the EACA and control groups. The EACA group ([median, 25th to 75th quartile] 15.6 mL/kg; 9.2 to 26.3 mL/kg) had less intraoperative blood loss than the control group (22.2 mL/kg; 14.3 to 36.3 mL/kg; p = 0.02). Postoperative chest tube output at 6 hours (p = 0.08), 12 hours (p = 0.07), and 24 hours (p = 0.08) was not significantly different between groups. Fewer EACA group patients required reexploration for bleeding (p < 0.05). There was no difference between groups in blood products transfused (in milliliters per kilogram or allogenic exposure per patient). Thromboelastography values (maximum amplitude [MA], whole blood clot lysis index at 30 minutes after MA) during CPB were better preserved in the EACA group.EACA reduced intraoperative blood loss but did not significantly decrease blood product transfusions. Lack of efficacy may be related to relative underdosing and should be further studied.

    View details for Web of Science ID 000080974400012

    View details for PubMedID 10392682

  • Fibrinolysis in pediatric patients undergoing cardiopulmonary bypass JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Williams, G. D., Bratton, S. L., Nielsen, N. J., Ramamoorthy, C. 1998; 12 (6): 633-638

    Abstract

    Thromboelastographic evaluation of the influence of fibrinolysis on blood loss and blood product transfusions in children during cardiac surgery.Prospective study.University-affiliated, pediatric medical center.Two hundred seventy-eight consecutive children undergoing cardiac surgery.Blood sampling for coagulation tests, including native and protamine-modified thromboelastography.Blood coagulation tests were measured before, during, and after cardiopulmonary bypass (CPB). Demographic data, perioperative blood loss, and blood product transfusions were prospectively recorded. Fibrinolysis was defined as thromboelastography of A30/MA less than 0.85 (MA, maximum amplitude; A30, amplitude 30 minutes after MA) and was noted in 3% of children pre-CPB, 16% during CPB, and 3% post-CPB. Fibrinolysis before CPB was associated with poor cardiac output. Fibrinolysis during CPB occurred in young children (aged 350 +/- 836 days) undergoing complex surgery with prolonged CPB (119 +/- 48.8 minutes) and deep hypothermia (25.6 degrees C +/- 4.7 degrees C). These patients received blood products after CPB and were not fibrinolytic after transfusion. They incurred similar blood loss (in mL/kg) and received similar volumes of blood products (mL/kg) as age-matched and surgery-matched patients without fibrinolysis.A group of children at risk for fibrinolysis during CPB was identified. However, fibrinolysis during CPB did not influence blood loss or the total volume of blood products transfused.

    View details for Web of Science ID 000077424200005

    View details for PubMedID 9854659

  • Association between age and blood loss in children undergoing open heart operations ANNALS OF THORACIC SURGERY Williams, G. D., Bratton, S. L., Riley, E. C., Ramamoorthy, C. 1998; 66 (3): 870-875

    Abstract

    Although recent studies indicated young children are at risk for increased perioperative hemorrhage after open heart operations, the associations between patient age, blood loss and blood product transfusions have not been fully defined in children.Perioperative blood loss and blood product transfusion data were recorded for 414 consecutive children undergoing open heart procedures. The children were in the following age groups: 1 month or younger, group 1; older than 1 month to 12 months, group 2; older than 1 year to 5 years, group 3; and older than 5 years, group 4.Postoperative blood loss and blood product transfusions were inversely related to age and differed significantly between the four age groups. Multiple preoperative and intraoperative factors that possibly influence hemostasis also differed significantly between age groups. Median units transfused within 72 hours differed significantly with age (p < 0.0001): group 1, 8 units (range, 1 to 19 units); group 2, 6 units (range, 0 to 21 units); group 3, 2 units (range, 0 to 23 units); and group 4, 0 units (range, 0 to 38 units).Blood loss and transfusions vary inversely with age. Per kilogram of body weight, neonates bled more and received more donor products than any other age group.

    View details for Web of Science ID 000076166100045

    View details for PubMedID 9768944

Footer Links:

Stanford Medicine Resources: