Ketosis After Cardiopulmonary Bypass in Children Is Associated With an Inadequate Balance Between Oxygen Transport and Consumption.

OBJECTIVES: Hyperglycemia after cardiac surgery and cardiopulmonary bypass in children has been associated with worse outcome; however, causality has never been proven. Furthermore, the benefit of tight glycemic control is inconsistent. The purpose of this study was to describe the metabolic constellation of children before, during, and after cardiopulmonary bypass, in order to identify a subset of patients that might benefit from insulin treatment. DESIGN: Prospective observational study, in which insulin treatment was initiated when postoperative blood glucose levels were more than 12 mmol/L (216 mg/dL). SETTING: Tertiary PICU. PATIENTS: Ninety-six patients 6 months to 16 years old undergoing cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Metabolic tests were performed before anesthesia, at the end of cardiopulmonary bypass, at PICU admission, and 4 and 12 hours after PICU admission, as well as 4 hours after initiation of insulin treatment. Ketosis was present in 17.9% patients at the end of cardiopulmonary bypass and in 31.2% at PICU admission. Young age was an independent risk factor for this condition. Ketosis at PICU admission was an independent risk factor for an increased difference between arterial and venous oxygen saturation. Four hours after admission (p = 0.05). Insulin corrected ketosis within 4 hours. CONCLUSIONS: In this study, we found a high prevalence of ketosis at PICU admission, especially in young children. This was independently associated with an imbalance between oxygen transport and consumption and was corrected by insulin. These results set the basis for future randomized controlled trials, to test whether this subgroup of patients might benefit from increased glucose intake and insulin during surgery to avoid ketosis, as improving oxygen transport and consumption might improve patient outcome.

Inflammatory and prothrombotic states in obese children of European descent.

Adipose tissue may release mediators that induce a chronic inflammatory state and alterations in coagulation, which contribute to insulin resistance, atherosclerosis, and thrombosis. We investigated whether inflammatory and/or prothrombotic states exist in obese children and assessed their interrelationship. Sixty-one subjects were recruited, aged between 6 and 16 years, to participate in a cross-sectional study at Children's University Hospital of Geneva. Selected pro/anti-inflammatory cytokines/chemokines and hemostasis parameters were measured in obese children and lean controls. Cardiovascular risk factors in the family were indexed. Fasting glucose level, insulin, prothrombin time (PT), fibrinogen, activated partial thromboplastin time (aPTT), D-dimer, endogenous thrombin potential (ETP), C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-10 (IL-10), interferon-γ-inducible-protein (IP-10), monocyte chemoattractant protein 1 (MCP-1), and interleukin-1 receptor antagonist (IL-1Ra) were measured. We estimated insulin resistance by homeostatic model assessment (HOMA). Anti- (IL-1Ra) and proinflammatory cytokines (MCP-1, IL-6) were significantly increased in obese children in comparison to the control group, even before puberty. Hemostasis was also altered in obese children with a significantly increased fibrinogen level, increased D-dimer, a shortened PT, as well as an increased ETP. No correlation was found between cytokine levels and hemostasis parameters, except for IL-6 and fibrinogen. Obese children present with inflammatory and prothrombotic states as early as 6 years of age and these states are similar in prepubertal and pubertal obese children. The cytokines IL-1Ra and MCP-1 were most significantly increased in obese children. Further investigation is necessary to determine if these cytokines, together with ETP, can reliably predict the development of diabetes and atherosclerosis.

Is the use of colloids for fluid replacement harmless in children?

PURPOSE OF REVIEW: Albumin has been regarded as the gold standard for maintaining adequate colloid osmotic pressure in children, but increased cost, the lack of clear-cut benefits for survival, and fear of transmission of unknown viruses have contributed to its replacement by hydroxyethyl starch and gelatin preparations. Each of the synthetic colloids has unique physicochemical characteristics that determine their likely efficacy and adverse effect profile. This review will examine the advantages and disadvantages of the use of different colloid solutions in children with a particular focus on their safety profile. RECENT FINDINGS: Dextrans are rarely used because of their negative effects on coagulation and potential for anaphylactic reactions. Gelatin and albumin have little effect on hemostasis, but the disadvantages of gelatin include its high anaphylactoid potential and limited beneficial volume effect. Tetrastarches have significantly fewer adverse effects on coagulation and renal function than the older hydroxyethyl starches and are now approved for children. Dissolving tetrastarches in a plasma-adapted, balanced solution rather than in saline further improves safety with regard to coagulation and acid-base balance. SUMMARY: Tetrastarches offer the best currently available compromise between cost-effectiveness and safety profile in children with preexisting normal renal function and coagulation.

Desflurane but not sevoflurane impairs airway and respiratory tissue mechanics in children with susceptible airways.

BACKGROUND: Although sevoflurane and desflurane exert bronchoactive effects, their impact on the airway and respiratory tissue mechanics have not been systematically compared in children, especially in those with airway susceptibility (AS). The aim of this study was to assess airway and respiratory tissue mechanics in children with and without AS during sevoflurane and desflurane anesthesia. METHODS: Respiratory system impedance was measured in healthy control children (group C, n = 20) and in those with AS (group AS, n = 20). Respiratory system impedance was determined during propofol anesthesia and during inhalation of sevoflurane and desflurane 1 minimum alveolar concentration in random order. Airway resistance, tissue damping, and elastance were determined from the respiratory system impedance spectra by model fitting. RESULTS: Children in group AS exhibited significantly higher respiratory impedance parameters compared with those in group C. Sevoflurane slightly decreased airway resistance (-7.0 +/- 1.5% vs. -4.8 +/- 2.4% in groups C and AS, respectively) in both groups. In contrast, desflurane caused elevations in airway resistance and tissue mechanical parameters, with markedly enhanced airway narrowing in children with AS (18.2 +/- 2.8% vs. 53.9 +/- 5%; P < 0.001 for airway resistance in groups C and AS, respectively). Neither the order of drug administration nor the time after the establishment of their steady state concentrations affected these findings. CONCLUSIONS: These results emphasized the deleterious effects of desflurane on the airways, particularly in children with susceptible airways in contrast with the consistent beneficial effects of sevoflurane, questioning the use of desflurane in children with AS.

Safety and efficacy of patient controlled epidural analgesia following pediatric spinal surgery.

BACKGROUND: Patient controlled epidural analgesia (PCEA) is uncommon in pediatric anesthesia. Because PCEA offers superior pain control compared with continuous epidural infusions in adults, we prospectively evaluated the analgesia efficacy and safety of PCEA in children and adolescents following extensive spinal surgery. METHODS: Following ethics committee approval, 100 consecutive children [age median (range) 14 (6-19) years] undergoing spinal surgery were studied until the seventh postoperative day, and 98 children received a PCEA. One or two epidural catheters were positioned under direct vision by the surgeon based on the number of vertebral segments operated upon. The epidural solution consisted of bupivacaine 0.0625%, fentanyl 1 microg.ml(-1) and clonidine 0.6 microg.ml(-1), delivered at a basal rate of 0.2 ml.kg(-1).h(-1) and a PCEA dose of 0.1 ml.kg(-1).h(-1)(max. 2 h(-1)). On the fourth postoperative day, PCEA was stopped and analgesia was continued with patient controlled analgesia (PCA) with morphine. RESULTS: During the PCEA regimen, the maximal scores of the revized facial scale were below 4 at rest with a very high satisfaction rate (>90%). Pain scores were higher during mobilization on the first postoperative day and when PCEA was switched to PCA. The overall incidence of adverse events was low and consisted primarily of technical problems and postoperative nausea and vomiting. Only two children experienced a complication requiring the discontinuation of the PCEA but there were no consequent adverse sequelae. CONCLUSIONS: The present study demonstrates that PCEA provides excellent pain relief following extensive spinal surgery and is associated with a low incidence of adverse events. The use of PCEA should be encouraged in children and adolescents following extensive spinal surgery.

Mechanical support availability in pediatric cardiac surgery: program size should not matter.

Intractable heart failure may require Extracorporeal Life Support (ECLS) techniques for rescue therapy. Nevertheless, in many small to middle-sized centers in Europe, this valuable resource is not available. In our University pediatric intensive care unit 0.9% of 1360 open-heart surgical patients required mechanical assistance over the latest 9 years with a survival rate of 69.2% and low residual morbidity. This favorable overall outcome suggests that regardless of the program size, it is possible to ensure the availability of efficient mechanical assistance that appears to be fundamental in a center performing surgery for complex congenital or acquired cardiac diseases.

Effect of cardiopulmonary bypass and aortic clamping on functional residual capacity and ventilation distribution in children.

OBJECTIVE: To characterize factors that contribute to lung function impairment after cardiopulmonary bypass, we assessed functional residual capacity and ventilation homogeneity during the perioperative period in children with congenital heart disease who are to undergo surgical repair. METHODS: Functional residual capacity and lung clearance index were measured by using a sulfur hexafluoride washout technique in 24 children (aged 0-10 years). Measurements of functional residual capacity and ventilation distribution were performed after induction of anesthesia, at different stages of the surgical procedure, and up to 90 minutes after skin closure. Anesthesia was standardized, and ventilator settings, including the fraction of inspired oxygen, were kept constant throughout the study period. RESULTS: Sternotomy and retractor insertion led to a significant increase in functional residual capacity (mean [SD], 24% [14%]), followed by a similar percentage decrease in the resting volume after a significant reduction in pulmonary blood flow during cardiopulmonary bypass with aortic clamping. Although reestablishing pulmonary blood flow increased functional residual capacity (10% [6%]), chest closure led to a decrease in functional residual capacity of 36% (14%) that only slightly improved during the first 90 minutes after surgical intervention. Changes in lung clearance index were affected conversely compared with changes in functional residual capacity at all assessment times. CONCLUSIONS: These results confirmed that chest wall condition and pulmonary circulation affect lung volumes and ventilation homogeneity. Although opening of the chest wall improved alveolar recruitment and ventilation homogeneity, blood flow appeared essential for alveolar stability, presumably by exerting a tethering force caused by the filled capillaries on the alveolar walls and therefore contributing to an increase in resting lung volume.

Should the use of modified Jackson Rees T-piece breathing system be abandoned in preschool children?

BACKGROUND: The Jackson Rees breathing system is commonly used for bag and mask ventilation in preschool children, although the lack of a pressure release valve can increase the risk of gastric insufflation. Therefore, we investigated the impact of bag and mask ventilation with a Jackson Rees system on functional residual capacity (FRC) and ventilation homogeneity and evaluated the effect of the level of training of the anesthesiologist in charge. METHODS: Functional residual capacity and ventilation homogeneity were measured in 74 children (1-6 years) undergoing general surgery and the level of training of the anesthesiologist was recorded. FRC was measured (i) after intubation and (ii) after gastric emptying. Sixty-four children were ventilated using a Jackson Rees system, whereas 10 children were ventilated using a circle system to compare these two breathing systems in the second phase of the protocol. RESULTS: Functional residual capacity and ventilation homogeneity increased in all patients following gastric emptying with the highest improvement (25%) being observed when nurse students were in charge of the ventilation with the Jackson Rees system. The lowest changes in FRC and ventilation homogeneity were observed when pediatric consultants were in charge, whereas ventilation by the pediatric nurse anesthetists led to significant gastric gas insufflation. However, the circle system was associated with significantly less gastric insufflation than the Jackson Rees system. CONCLUSIONS: The efficacy of bag and mask ventilation was highly dependent on the training of the anesthesiologist with consultants demonstrating significantly better skills than any of the other groups. As the circle system is associated with a much steeper learning curve than the Jackson Rees system, its use in daily routine practice may prevent ventilatory impairment induced by gastric insufflation.

Cardiac rhythm and left ventricular function of infants at 1 MAC sevoflurane and halothane.

BACKGROUND: The implementation of sevoflurane in pediatric anesthesia practice led to a decrease in the incidence of cardiac arrest previously reported with halothane. Nevertheless, the effects of sevoflurane on cardiac rhythm and function have not been systematically investigated in infants. Thus, we compared cardiac rhythm and left ventricular function at 1 MAC sevoflurane and halothane anesthesia and investigated the potential benefit effect of atropine. METHODS: Twenty infants ASA physical status I or II were randomly assigned to have anesthesia induced with either sevoflurane (up to 5%) or halothane (up to 1.5%). After insertion of an i.v. line, anesthesia was maintained at 1 MAC sevoflurane (group S) or 1 MAC halothane (group H) with infants breathing spontaneously in 100% oxygen. Cardiac output and contractility were measured by transthoracic echocardiography. Three sets of hemodynamic parameters were averaged prior to and after administration of 20 microg x kg(-1) of i.v. atropine. RESULTS: Infants breathing spontaneously 1 MAC halothane or 1 MAC sevoflurane were found to have comparable hemodynamic parameters. After atropine administration, heart rate and cardiac index (CI) increased significantly in both groups (19.6 +/- 7.6% in group H and 21.3 +/- 13.1% in group S, 18.6 +/- 8.8% in group H and 17.7 +/- 12% in group S respectively). Moreover, atropine induced an increase in left ventricular shortening fraction with no difference between groups. In contrast, only infants in group S presented a significant increase in ejection fraction. CONCLUSIONS: Indices of left ventricular function were comparable between groups with no clinically significant change following atropine administration. The present study confirms the favorable hemodynamic profile of sevoflurane in infants breathing spontaneously at 1 MAC concentration.