Tolerability and efficacy of a reduced dose adenosine stress cardiac magnetic resonance protocol under general anesthesia in infants and children.

BACKGROUND: Intravenous adenosine induces pharmacological stress by causing vasodilatation and thus carries the risk of severe hypotension when combined with vasodilatory effects of anesthetic agents. OBJECTIVE: This study describes our experience with a reduced dose adenosine cardiac magnetic resonance imaging (MRI) protocol in young children under general anesthesia (GA). MATERIALS AND METHODS: This is a retrospective report of all patients from birth to 18 years who underwent adenosine stress cardiac MRI under GA between August 2018 and November 2022. Based on our anecdotal experience of severe adverse effects in patients receiving adenosine infusion under GA and in discussion with the pediatric anesthesia team, we developed a modified protocol starting at a dose of 110 mcg/kg/min with incremental escalation to a full dose of 140 mcg/kg/min to achieve desired hemodynamic effect. RESULTS: Twenty-two children (mean age 6.5 years, mean weight 28 kg) satisfied the inclusion criteria. The diagnoses included Kawasaki disease (7), anomalous aortic origin of left coronary artery (3), anomalous aortic origin of right coronary artery (2), coronary fistula (3), repaired d-transposition of great arteries (2), repaired anomalous left coronary artery from pulmonary artery (2), repaired truncus arteriosus with left coronary artery occlusion (1), extracardiac-Fontan with left coronary artery myocardial bridge (1), and post heart transplantation (1). Nine patients needed dose escalation beyond 110 mcg/kg/min. Two patients had transient hypotension during testing (systemic blood pressure drop > 25 mmHg). No patient developed significant heart block or bronchospasm. Six patients (repeat study in one) demonstrated inducible perfusion defects (27%) on stress perfusion sequences-5 of whom had confirmed significant coronary abnormalities on angiography or direct surgical inspection. CONCLUSION: A reduced/incremental dose adenosine stress cardiac MRI protocol under GA in children is safe and feasible. This avoids severe hypotension which is both unsafe and may result in inaccurate data.

Role of Cross-Sectional Imaging in Pediatric Interventional Cardiac Catheterization.

Management of congenital heart disease (CHD) has recently increased utilization of cross-sectional imaging to plan percutaneous interventions. Cardiac computed tomography (CT) and cardiac magnetic resonance (CMR) imaging have become indispensable tools for pre-procedural planning prior to intervention in the pediatric cardiac catheterization lab. In this article, we review several common indications for referral and the impact of cross-sectional imaging on procedural planning, success, and patient surveillance.

Anesthetic Considerations in Pediatric Patients With Acute Decompensated Heart Failure.

Acute decompensated heart failure (ADHF) in pediatrics is a significant cause for morbidity and mortality in children. Congenital heart disease and cardiomyopathy are the leading etiologies of ADHF. It is common for these children to undergo diagnostic, therapeutic, or surgical procedure under anesthesia, which may be associated with significant morbidity and mortality. The importance of preanesthetic multidisciplinary planning with all involved teams, including anesthesia, cardiology, intensive care, perfusion, and cardiac surgery, cannot be emphasized enough. In order to safely manage these patients, it is imperative for the anesthesiologist to understand the complex pathophysiological interactions between cardiopulmonary systems and anesthesia during these procedures. This review discusses the etiology, pathophysiology, clinical manifestations, and perioperative management of these patients.

Blood Conservation and Hemostasis Management in Pediatric Cardiac Surgery.

Pediatric cardiac surgery is associated with significant perioperative blood loss needing blood product transfusion. Transfusion carries serious risks and implications on clinical outcomes in this vulnerable population. The need for transfusion is higher in children and is attributed to several factors including immaturity of the hemostatic system, hemodilution from the CPB circuit, excessive activation of the hemostatic system, and preoperative anticoagulant drugs. Other patient characteristics such as smaller relative size of the patient, higher metabolic and oxygen requirements make successful blood transfusion management extremely challenging in this population and require meticulous planning and multidisciplinary teamwork. In this narrative review we aim to summarize risks and complications associated with blood transfusion in pediatric cardiac surgery and also to summarize perioperative coagulation management and blood conservation strategies.

A pilot study on secondhand tobacco exposure: parental knowledge about health impact and feasibility of cessation.

INTRODUCTION: As the primary source of smoke exposure is in the home, the smoking behaviors of parents and other caregivers are key determinants of a child's exposure to secondhand smoke. The perioperative period offers an opportunity to discuss smoking cessation strategies. METHODS: This prospective study included 97 parents or caregivers of patients undergoing dental surgery. Caregivers were surveyed in the dental waiting room during the preoperative phase. The primary aim was to determine the feasibility of using the preoperative encounter to offer smoking cessation resources to parents of pediatric patients. The secondary aim was to compare willingness to receive smoking cessation resources according to the knowledge of the risks of secondhand smoking (ie, being aware of secondhand smoking and knowing that it posed a risk to their child). RESULTS: Awareness of risks due to secondhand smoking was 65% in the overall cohort and 58% among current smokers (P=0.284 vs nonsmokers). Among smokers in our study, only a small percentage (12%) were interested in smoking cessation help. Knowledge of the risks of secondhand smoke may not be sufficient for smokers to express willingness to receive help. CONCLUSION: The outpatient clinic may be a teaching opportunity for smoking cessation for caregivers. However, we found that only a small percentage of caregivers were interested in receiving information about smoking cessation. This was despite the fact they were aware of the potential adverse effects of secondhand smoke on their children.

Correlation of Lactic Acid and Base Deficit Values Obtained From Arterial and Peripheral Venous Samples in a Pediatric Population During Intraoperative Care.

Lactic acid and base deficit (BD) values are frequently monitored in the intensive care unit and operating room setting to evaluate oxygenation, ventilation, cardiac output, and peripheral perfusion. Although generally obtained from an arterial cannula, such access may not always be available. The current study prospectively investigates the correlation of arterial and peripheral venous values of BD and lactic acid. The study cohort included 48 patients. Arterial BD values ranged from -8 to 4 mEq/L and peripheral venous BD values ranged from -8 to 4 mEq/L. Arterial lactic acid values ranged from 0.36 to 2.45 µmol/L and peripheral venous lactic acid values ranged from 0.38 to 4 µmol/L. The arterial BD (-0.4 ± 2.2 mEq/L) was not significantly different from the peripheral venous BD (-0.6 ± 2.2 mEq/L). The arterial lactic acid (1.0 ± 0.5 µmol/L) was not significantly different from the peripheral venous lactic acid (1.1 ± 0.6 µmol/L). Pearson correlation coefficients demonstrated a very high correlation between arterial and peripheral venous BD ( r = .88, P < .001) and between arterial and peripheral venous lactic acid ( r = .67, P < .001). Bland-Altman plots of both pairs of measures showed that the majority of observations fell within the 95% limits of agreement. Least-squares regression indicated that a 1-unit increase in arterial BD corresponded to a 0.9-unit increase in peripheral venous BD (95% confidence interval [CI]: 0.7-1.0; P < .001) and a 1-unit increase in arterial lactic acid corresponded to a 0.9-unit increase in peripheral venous lactic acid (95% CI: 0.6-1.2; P < .001). These data demonstrate that there is a clinically useful correlation between arterial and peripheral venous lactic acid and BD values.

Perioperative care in an adolescent patient with heparin-induced thrombocytopenia for placement of a cardiac assist device and heart transplantation: case report and literature review.

Heparin-induced thrombocytopenia (HIT) can cause life-threatening complications following the administration of heparin. Discontinuation of all sources of heparin exposure and the use of alternative agents for anticoagulation are necessary when HIT is suspected or diagnosed. We present the successful use of bivalirudin anticoagulation in an adolescent patient during cardiopulmonary bypass who underwent both placement of a left ventricular assist device and subsequent heart transplantation within a 36-hour period. The pathophysiology and diagnosis of HIT are reviewed, previous reports of the use of direct thrombin inhibitors for cardiac surgery are presented, and potential dosing regimens for bivalirudin are discussed.

Cuffed endotracheal tubes in children: the effect of the size of the cuffed endotracheal tube on intracuff pressure.

BACKGROUND: In children, the size of the cuffed endotracheal tube is based on various age-based formulas. However, such formulas may over or underestimate the size of the cuffed endotracheal tube. There are no data on the impact of different-sized cuffed endotracheal tubes (ETT) on the intracuff pressure in children. AIM: The current study measures intracuff pressure with different-sized cuffed ETT. METHOD: The study was conducted in an in vitro and in vivo phase. For the in vitro phase, 10 cuffed ETT of size 4.0, 4.5, and 5 mm internal diameter (ID) each were randomly placed inside a 1.0 cm ID plastic tube (mimicking the trachea), which was in turn connected to a 1 l test lung. After inflation of the cuff using the air leak test at a continuous positive airway pressure of 20 cmH2 O, the intracuff pressure was measured. The in vivo phase was conducted in 100 children (4-8 years) and were randomly divided into two groups to receive either a cuffed endotracheal tube based on the Khine formula (Group R) or a cuffed endotracheal tube that was a half-size (0.5 mm ID) smaller (Group S). Following the inflation of the cuff to seal the trachea, the intracuff pressure was measured. RESULTS: In the in vitro phase, the intracuff pressure was 45 ± 6, 23 ± 1, and 14 ± 6 cmH2 O with size 4.0, 4.5, and 5 mm ID cuffed ETT, respectively (F-test P < 0.001 for difference among three groups). In the in vivo phase, the mean intracuff pressure in Group R was 25 ± 19 cmH2 O vs 37 ± 35 cmH2 O in Group S (95% CI of difference: 1, 23; P = 0.039). CONCLUSION: If the cuffed endotracheal tube is too small, the trachea can still be sealed by inflating the cuff with additional air. However, this transforms the cuff from the intended high-volume, low-pressure cuff to an undesirable high-volume, high-pressure cuff.

The Correlation of Two Cerebral Saturation Monitors With Jugular Bulb Oxygen Saturation in Children Undergoing Cardiopulmonary Bypass for Congenital Heart Surgery.

BACKGROUND: Near-infrared spectroscopy (NIRS) is a noninvasive monitoring technique that measures regional cerebral oxygen saturation (rSO2). OBJECTIVES: The primary aim was to compare the output of 2 NIRS-based cerebral oximetry devices, FORESIGHT (CAS Medical Systems Inc, Branford, Connecticut) and INVOS (Covidien, Boulder, Colorado), to venous oxygen saturations from the jugular venous bulb at cannulation and decannulation of the superior vena cava (SVC). Secondary objectives included evaluating correlations of cerebral saturation, as measured by the NIRS devices, with mean arterial blood pressure (MAP), measured by an invasive arterial line, and end-tidal CO2 (ETCO2). METHODS: Near-infrared spectroscopy, MAP, and ETCO2 data were collected at 13 defined events during each case when hemodynamic instability was expected. At SVC cannulation and decannulation, a 0.1 mL sample of blood was collected from the jugular bulb by the surgeon using a long angiocatheter. The oxygen saturation of these blood samples was measured using an AVOX device and compared with contemporaneous readings from the NIRS probes. Mixed-effects linear regression was used to correlate MAP or ETCO2 with cerebral oxygen saturation (by NIRS) at each time point. RESULTS: Children undergoing cardiopulmonary bypass for congenital heart surgery (n = 34) were enrolled in the study. At SVC cannulation, both INVOS ( r = .78) and FORESIGHT ( r = .59) were correlated with AVOX data at P < .001, although the correlation with INVOS was significantly stronger ( P = .003). At SVC decannulation, INVOS ( r = .68; P < .001) and FORESIGHT ( r = .60; P < .001) were similarly correlated with jugular venous rSO2. Correlations of rSO2 (by NIRS) with MAP and ETCO2 levels were stronger than correlations between rSO2 change and change in MAP or ETCO2. CONCLUSION: INVOS correlated more strongly than FORESIGHT with the jugular bulb rSO2 at SVC cannulation but may have underestimated oxygen saturation at low rSO2 values. Data from both NIRS devices were correlated with MAP and ETCO2 over the case duration.

Revisiting acute normovolemic hemodilution and blood transfusion during pediatric cardiac surgery: a prospective observational study.

BACKGROUND: The majority of allogeneic transfusions occur in the perioperative setting, especially during cardiac surgery. In addition to the economic implications, there is emerging evidence that blood transfusion may increase both morbidity and mortality. Acute normovolemic hemodilution (ANH) may limit the need for blood products. OBJECTIVES: The primary objective of this study was to determine if the method of blood collection (syringe or bag) during the ANH process impacted the platelet count and function. The secondary objectives included the need for perioperative blood transfusions during the procedure and in the intensive care unit. In addition, we assessed these outcomes' associations with ANH parameters including the method of collection, time of storage, and volume removed. METHODS: Data were collected prospectively from 50 patients undergoing cardiac surgery on cardiopulmonary bypass over a 6-month period. Platelet count and function were measured for the ANH blood immediately after collection and again prior to transfusing to the patient at the end of cardiopulmonary bypass. Other data collected included ANH volume, length of storage, and the quantity of all blood products given throughout the perioperative period. RESULTS: No change in platelet count or function was noted regardless of the length of time or collection method for the ANH blood. Twenty-three patients received blood or blood products in the operating room or the intensive care unit, while 27 patients received no blood transfusion during their entire hospitalization. Higher ANH volume (ml·kg-1 ) and longer storage time were associated with a greater need for intraoperative transfusions. CONCLUSION: Acute normovolemic hemodilution protects the platelets from the untoward effects of cardiopulmonary bypass and offers an important autologous blood product that improves hemostasis at the conclusion of surgery. Platelet count and function are preserved regardless of the method of collection or the length of storage. The volume of ANH removed appears to be an important determinant of blood product use and further understanding of the impact of this variable is a future direction of upcoming prospective research.

Learning From Experience: Improving Early Tracheal Extubation Success After Congenital Cardiac Surgery.

OBJECTIVES: The many advantages of early tracheal extubation following congenital cardiac surgery in young infants and children are now widely recognized. Benefits include avoiding the morbidity associated with prolonged intubation and the consequences of sedation and positive pressure ventilation in the setting of altered cardiopulmonary physiology. Our practice of tracheal extubation of young infants in the operating room following cardiac surgery has evolved and new challenges in the arena of postoperative sedation and pain management have appeared. DESIGN: Review our institutional outcomes associated with early tracheal extubation following congenital cardiac surgery. PATIENTS: Inclusion criteria included all children less than 1 year old who underwent congenital cardiac surgery between October 1, 2010, and October 24, 2013. MEASUREMENTS AND MAIN RESULTS: A total of 416 patients less than 1 year old were included. Of the 416 patients, 234 underwent tracheal extubation in the operating room (56%) with 25 requiring reintubation (10.7%), either immediately or following admission to the cardiothoracic ICU. Of the 25 patients extubated in the operating room who required reintubation, 22 failed within 24 hours of cardiothoracic ICU admission; 10 failures were directly related to narcotic doses that resulted in respiratory depression. CONCLUSIONS: As a result of this review, we have instituted changes in our cardiothoracic ICU postoperative care plans. We have developed a neonatal delirium score, and have adopted the "Kangaroo Care" approach that was first popularized in neonatal ICUs. This provision allows for the early parental holding of infants following admission to the cardiothoracic ICU and allows for appropriately selected parents to sleep in the same beds alongside their postoperative children.

A Lousy Reason for Surgery Cancellations.

Cancellation of surgery has significant adverse impact on patients, health care providers, and their associated facilities. Although head lice infestation has not been shown to be associated with adverse surgical outcomes, it often prompts case cancellation by surgical and anesthesia personnel. The purpose of our study was to evaluate the extent and impact of surgery cancellations due to head lice infestation. In our study, a total of 9 patients were cancelled over a 3-year period. Although there is no direct evidence to show that head lice infestation poses a risk to surgical outcomes, the possibility of underlying secondary bacterial infection at the skin excoriation site is often the concern in these patients. This study offers the first investigation into the impact of head lice infections on operating room cancellations, which may prove to be a potential source of intervention to prevent cancellations.

Effect of dexmedetomidine on the QT interval in pediatric patients undergoing general anesthesia.

BACKGROUND: Recent years have seen an increase in the use of dexmedetomidine in pediatric patients presenting for surgical procedures. However, only a limited number of studies have evaluated its effects on the QT interval in this patient group. To address this lack of knowledge, we have evaluated the effects of dexmedetomidine on the QT interval in children receiving sevoflurane anesthesia. METHODS: This study was a prospective case-control study in which pediatric patients presenting for anesthetic care were divided into two groups--the dexmedetomidine (D) and control (C) groups. Three electrocardiograms (ECGs) were obtained on each patient, including a baseline ECG (T1) prior to anesthetic induction and an ECG after the induction of anesthesia with sevoflurane (T2). In group D, the third ECG was obtained 2 min after the administration of dexmedetomidine, which in turn was started immediately after the T2 ECG reading (T3D); in group C, it was obtained 2 min after the T2 reading (T3C). Statistical analysis was performed using analysis of variance to compare the QT intervals at the three time points outlined above. RESULTS: A total of 50 patients were recruited to the study, ranging in age from 1 to 16 [mean 7.9 ± 4.1 (SD) years]. There were 25 patients in group C and 25 in group D. There were no statistical differences in the demographics between the 2 groups. In group C, the QTc was noted to increase progressively with the administration of sevoflurane (T3C vs. T1; P = 0.006). In group D, following the administration of dexmedetomidine, there was a significant decrease in the QTc relative to the post-induction value [436 ± 25 (T2) vs. 418 ± 17 ms (T3D); P < 0.01]. CONCLUSION: A progressive lengthening of the QTc interval following the administration of sevoflurane was observed in the control group. In the dexmedetomidine group, there was a significant shortening of the QTc interval following the administration of dexmedetomidine compared to the length of the post-induction QTc interval and when compared to the control group.