Correspondence
As has been eloquently pointed out before in an editorial by Sneyd and O’Sullivan, it is crucially important to clarify the motivation for choosing a particular approach to facilitate endotracheal intubation (2). While the practice of nonrelaxant intubation in children appears to be rather common, valid alternatives to nonrelaxant approaches exist in virtually all but the shortest cases that customarily require tracheal intubation such as adenotonsillectomies. The available data, as recently reviewed by Aouad et al. (3), suggest that relaxant-free intubation strategies have not been found to provide better intubating conditions than relaxant techniques in direct comparisons. A carefully conducted trial in an adult population by Mencke et al. (4) further demonstrated that the quality of intubating conditions was a significant contributor to laryngeal morbidity and that ‘good’ and ‘excellent’ intubation conditions were not equivalent in terms of risk of injury. While no such data exist in the pediatric population, I fear the concern over a similar relationship is not misplaced. Therefore, any
further scientific inquiry into methods of relaxant-free intubation should clearly explain the rationale for pursuing such a technique in terms of expected benefit to the patient and in terms of potential risk of airway morbidity from suboptimal intubating conditions. Disclosures None. Conflict of interest No conflicts of interest declared. Matthias W. K€ onig Department of Anesthesiology, Division of Pediatric Anesthesia, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Email: [email protected] doi:10.1111/pan.12460
References 1 Liu HC, Tao WK, Zeng RF et al. Dose requirements of remifentanil for intubation in nonparalyzed Chinese children. Pediatr Anesth 2014; 24: 505–509. 2 Sneyd JR, O’Sullivan EO. Tracheal intubation without neuromuscular blocking agents: is
there any point? Br J Anaesth 2010; 104: 535– 537. 3 Aouad MT, Yazbeck-Karam VG, Mallat CE et al. The effect of adjuvant drugs on the quality of tracheal intubation without muscle relaxant in children: a systematic review of
randomized trials. Pediatr Anesth 2012; 22: 616–626. 4 Mencke T, Echternach M, Kleinschmidt S et al. Laryngeal morbidity and quality of tracheal intubation. Anesthesiology 2003; 98: 1049–1056.
Transesophageal echocardiography during noncardiac pediatric surgery SIR—Transesophageal echocardiography (TEE) is rarely used during pediatric noncardiac surgery. However, it can offer relevant information to treat complex hemodynamic conditions, guide fluid replacement or monitor cardiac function. Recently, we used TEE in two pediatric patients as intraoperative monitoring. The first patient was an 18-month-old boy weighing 8.8 kg, with Alagille’s syndrome. Preoperative echocardiography revealed a moderate enlargement of cardiac chambers with an ejection fraction of 47%. Systolic pulmonary artery pressure (SPAP) was estimated at 50% of systemic value. The right ventricular outflow tract (RVOT) was normal, with a moderate hypoplasia of both branches of the pulmonary artery. A liver living donor transplant was scheduled. TEE was used to evaluate possible additional overload of the right ventricle. Surgery was uneventful. Mid-esophageal four- and twochamber views, along with transgastric mid-papillary 892
images, were frequently assessed to guide the fluid administration and evaluate the need for inotropic support. Estimated blood volume was 660 ml, and estimated bleeding was 600 ml. Total intraoperative fluid administration was 1280 ml. The patient was extubated on the next day, and no complications attributable to fluid administration or cardiac dysfunction were observed in the postoperative period. The second patient was a 14-year-old, 45-kg boy, with a nonidentified myopathy and dilated myocardiopathy, scheduled for laparoscopic cholecystectomy. He was receiving digoxin and furosemide. A preoperative echocardiography showed severe dilation of left chambers, severe mitral insufficiency, an ejection fraction of 38%, and an estimated SPAP of 50 mm Hg. To control and treat modifications in cardiac function determined by pneumoperitoneum, TEE was added to the intraoperative monitoring. Induction was performed with 2.5 mgkg1 © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 24 (2014) 879–895
Correspondence
of ketamine and 0.5 mgkg1 of atracurium. Anesthesia was maintained with a propofol and remifentanil infusion with a target control infusion for both drugs between 2 and 3 lgml1. Bispectral index was kept near 40 during the procedure. Postinduction echocardiography revealed no changes. Calculated SPAP at that time was 35, and a central venous pressure (CVP) was 14 mm Hg. After the insufflation of pneumoperitoneum, CVP increased to 20 mm Hg and no changes in arterial pressure (AP) or ventricular volume were observed. When the required position for surgery (moderate reverse Trendelenburg) was established, AP decreased to 60/40 and a reduction of left ventricular volume was observed. Considering the reduced contractile function and a dilated left ventricle, a dobutamine infusion at 4 lgkg1min1 was preferred over fluid administration. An evident improvement of cardiac contractility and recovery of AP were observed. Surgery was completed without incidents, and the patient was extubated at the end of the procedure. Dobutamine was progressively reduced after extubation and stopped 30 min later. These cases probably show the two most important benefits of the use of TEE in noncardiac pediatric surgery: management of fluid administration and assessment of cardiac function. In the first patient, the overloaded RV and the possible need to administer an important amount of fluids in a short period of time to maintain hemodynamic conditions, made it valuable to have a reliable indicator of the ventricular filling conditions. Filling pressure has been used to define preload. However, it has been shown that they may not reflect the real filling conditions, secondary to factors such as contractility, vascular tone, thoraco-pulmonar distensibility, distensibility of the chamber in which measurements are made, and high insufflation pressures (1), all of which may be present during surgery.
Changes produced by pneumoperitoneum are well known and cause slight hemodynamic adjustments in patients with a normal heart. However, these changes can be unpredictable in patients with reduced cardiac function. Changes observed after the induction of pneumoperitoneum can help explain some of the limitations of standard monitoring and justify the use of TEE in selected patients. The initial increase of CVP after the establishment of pneumoperitoneum is not the result of an increase of ventricular volume. It is caused by an increase of intraabdominal pressure produced by the pneumoperitoneum that is transmitted to the thorax, reducing the distensibility of the right atrium and explaining the increase in CVP measurement, in spite of the reduction of venous return (2,3). Rational support therapy can be provided when preload conditions and contractility can be assessed, and the response to therapy immediately evaluated. Ventricular filling and cardiac output can be reliably quantified by TEE. However, qualitative evaluation has also been proven adequate to evaluate cardiac function (4) and requires a shorter training period. Problems such as equipment availability, training, image interpretation, or complications limit the use of TEE. Proper training of the anesthesiologists involved is mandatory to make it an important monitoring tool in some critical pediatric surgical patients. Conflict of interest We declare no conflicts of interest. Mario R. Concha1, Ver onica F. Mertz1, Ricardo S. Fuentes1 & Juan Carlos Pattillo2 1 Divisi on de Anestesiologıa, Facultad de Medicina, Pontificia Universidad Cat olica de Chile, Santiago, Chile 2 Secci on Cirugıa Pedi atrica, Divisi on de Cirugıa, Facultad de Medicina, Pontificia Universidad Cat olica de Chile, Santiago, Chile Email: [email protected] doi:10.1111/pan.12464
References 1 Raper R, Sibbald WJ. Misled by the wedge? The Swan-Ganz catheter and left ventricular preload. Chest 1986; 89: 427–434. 2 Cunningham AJ, Turner J, Rosenbaum S et al. Transoesophageal echocardiographic assessment of haemodynamic function during
© 2014 John Wiley & Sons Ltd Pediatric Anesthesia 24 (2014) 879–895
laparoscopic cholecystectomy. Br J Anaesth 1993; 70: 621–625. 3 Smith I, Benzie RJ, Gordon NL et al. Cardiovascular effects of peritoneal insufflation of carbon dioxide for laparoscopy. Br Med J 1971; 3: 410–411.
4 Melamed R, Sprenkle MD, Ulstad VK et al. Assessment of left ventricular function by intensivists using hand-held echocardiography. Chest 2009; 135: 1416–1420.
893
As has been eloquently pointed out before in an editorial by Sneyd and O’Sullivan, it is crucially important to clarify the motivation for choosing a particular approach to facilitate endotracheal intubation (2). While the practice of nonrelaxant intubation in children appears to be rather common, valid alternatives to nonrelaxant approaches exist in virtually all but the shortest cases that customarily require tracheal intubation such as adenotonsillectomies. The available data, as recently reviewed by Aouad et al. (3), suggest that relaxant-free intubation strategies have not been found to provide better intubating conditions than relaxant techniques in direct comparisons. A carefully conducted trial in an adult population by Mencke et al. (4) further demonstrated that the quality of intubating conditions was a significant contributor to laryngeal morbidity and that ‘good’ and ‘excellent’ intubation conditions were not equivalent in terms of risk of injury. While no such data exist in the pediatric population, I fear the concern over a similar relationship is not misplaced. Therefore, any
further scientific inquiry into methods of relaxant-free intubation should clearly explain the rationale for pursuing such a technique in terms of expected benefit to the patient and in terms of potential risk of airway morbidity from suboptimal intubating conditions. Disclosures None. Conflict of interest No conflicts of interest declared. Matthias W. K€ onig Department of Anesthesiology, Division of Pediatric Anesthesia, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Email: [email protected] doi:10.1111/pan.12460
References 1 Liu HC, Tao WK, Zeng RF et al. Dose requirements of remifentanil for intubation in nonparalyzed Chinese children. Pediatr Anesth 2014; 24: 505–509. 2 Sneyd JR, O’Sullivan EO. Tracheal intubation without neuromuscular blocking agents: is
there any point? Br J Anaesth 2010; 104: 535– 537. 3 Aouad MT, Yazbeck-Karam VG, Mallat CE et al. The effect of adjuvant drugs on the quality of tracheal intubation without muscle relaxant in children: a systematic review of
randomized trials. Pediatr Anesth 2012; 22: 616–626. 4 Mencke T, Echternach M, Kleinschmidt S et al. Laryngeal morbidity and quality of tracheal intubation. Anesthesiology 2003; 98: 1049–1056.
Transesophageal echocardiography during noncardiac pediatric surgery SIR—Transesophageal echocardiography (TEE) is rarely used during pediatric noncardiac surgery. However, it can offer relevant information to treat complex hemodynamic conditions, guide fluid replacement or monitor cardiac function. Recently, we used TEE in two pediatric patients as intraoperative monitoring. The first patient was an 18-month-old boy weighing 8.8 kg, with Alagille’s syndrome. Preoperative echocardiography revealed a moderate enlargement of cardiac chambers with an ejection fraction of 47%. Systolic pulmonary artery pressure (SPAP) was estimated at 50% of systemic value. The right ventricular outflow tract (RVOT) was normal, with a moderate hypoplasia of both branches of the pulmonary artery. A liver living donor transplant was scheduled. TEE was used to evaluate possible additional overload of the right ventricle. Surgery was uneventful. Mid-esophageal four- and twochamber views, along with transgastric mid-papillary 892
images, were frequently assessed to guide the fluid administration and evaluate the need for inotropic support. Estimated blood volume was 660 ml, and estimated bleeding was 600 ml. Total intraoperative fluid administration was 1280 ml. The patient was extubated on the next day, and no complications attributable to fluid administration or cardiac dysfunction were observed in the postoperative period. The second patient was a 14-year-old, 45-kg boy, with a nonidentified myopathy and dilated myocardiopathy, scheduled for laparoscopic cholecystectomy. He was receiving digoxin and furosemide. A preoperative echocardiography showed severe dilation of left chambers, severe mitral insufficiency, an ejection fraction of 38%, and an estimated SPAP of 50 mm Hg. To control and treat modifications in cardiac function determined by pneumoperitoneum, TEE was added to the intraoperative monitoring. Induction was performed with 2.5 mgkg1 © 2014 John Wiley & Sons Ltd Pediatric Anesthesia 24 (2014) 879–895
Correspondence
of ketamine and 0.5 mgkg1 of atracurium. Anesthesia was maintained with a propofol and remifentanil infusion with a target control infusion for both drugs between 2 and 3 lgml1. Bispectral index was kept near 40 during the procedure. Postinduction echocardiography revealed no changes. Calculated SPAP at that time was 35, and a central venous pressure (CVP) was 14 mm Hg. After the insufflation of pneumoperitoneum, CVP increased to 20 mm Hg and no changes in arterial pressure (AP) or ventricular volume were observed. When the required position for surgery (moderate reverse Trendelenburg) was established, AP decreased to 60/40 and a reduction of left ventricular volume was observed. Considering the reduced contractile function and a dilated left ventricle, a dobutamine infusion at 4 lgkg1min1 was preferred over fluid administration. An evident improvement of cardiac contractility and recovery of AP were observed. Surgery was completed without incidents, and the patient was extubated at the end of the procedure. Dobutamine was progressively reduced after extubation and stopped 30 min later. These cases probably show the two most important benefits of the use of TEE in noncardiac pediatric surgery: management of fluid administration and assessment of cardiac function. In the first patient, the overloaded RV and the possible need to administer an important amount of fluids in a short period of time to maintain hemodynamic conditions, made it valuable to have a reliable indicator of the ventricular filling conditions. Filling pressure has been used to define preload. However, it has been shown that they may not reflect the real filling conditions, secondary to factors such as contractility, vascular tone, thoraco-pulmonar distensibility, distensibility of the chamber in which measurements are made, and high insufflation pressures (1), all of which may be present during surgery.
Changes produced by pneumoperitoneum are well known and cause slight hemodynamic adjustments in patients with a normal heart. However, these changes can be unpredictable in patients with reduced cardiac function. Changes observed after the induction of pneumoperitoneum can help explain some of the limitations of standard monitoring and justify the use of TEE in selected patients. The initial increase of CVP after the establishment of pneumoperitoneum is not the result of an increase of ventricular volume. It is caused by an increase of intraabdominal pressure produced by the pneumoperitoneum that is transmitted to the thorax, reducing the distensibility of the right atrium and explaining the increase in CVP measurement, in spite of the reduction of venous return (2,3). Rational support therapy can be provided when preload conditions and contractility can be assessed, and the response to therapy immediately evaluated. Ventricular filling and cardiac output can be reliably quantified by TEE. However, qualitative evaluation has also been proven adequate to evaluate cardiac function (4) and requires a shorter training period. Problems such as equipment availability, training, image interpretation, or complications limit the use of TEE. Proper training of the anesthesiologists involved is mandatory to make it an important monitoring tool in some critical pediatric surgical patients. Conflict of interest We declare no conflicts of interest. Mario R. Concha1, Ver onica F. Mertz1, Ricardo S. Fuentes1 & Juan Carlos Pattillo2 1 Divisi on de Anestesiologıa, Facultad de Medicina, Pontificia Universidad Cat olica de Chile, Santiago, Chile 2 Secci on Cirugıa Pedi atrica, Divisi on de Cirugıa, Facultad de Medicina, Pontificia Universidad Cat olica de Chile, Santiago, Chile Email: [email protected] doi:10.1111/pan.12464
References 1 Raper R, Sibbald WJ. Misled by the wedge? The Swan-Ganz catheter and left ventricular preload. Chest 1986; 89: 427–434. 2 Cunningham AJ, Turner J, Rosenbaum S et al. Transoesophageal echocardiographic assessment of haemodynamic function during
© 2014 John Wiley & Sons Ltd Pediatric Anesthesia 24 (2014) 879–895
laparoscopic cholecystectomy. Br J Anaesth 1993; 70: 621–625. 3 Smith I, Benzie RJ, Gordon NL et al. Cardiovascular effects of peritoneal insufflation of carbon dioxide for laparoscopy. Br Med J 1971; 3: 410–411.
4 Melamed R, Sprenkle MD, Ulstad VK et al. Assessment of left ventricular function by intensivists using hand-held echocardiography. Chest 2009; 135: 1416–1420.
893
