Impact of Capnoperitoneum on Renal Perfusion and Urine Production in Infant and Adolescent Pigs: Crystalloid versus Colloid Fluid Resuscitation.

BACKGROUND: Infants are likely to develop anuria during laparoscopy which is uncommon in older patients. The reason for this susceptibility remains unknown. We compared the impact of CO2 pneumoperitoneum on renal perfusion and urine production in piglets compared with adolescent pigs. We furthermore investigated the effects of different resuscitation strategies. MATERIALS AND METHODS: Male piglets (n = 21) were divided into four groups: (a) infant controls (n = 5), (b) infants with crystalloid restitution (n = 6), (c) infants with colloidal restitution (n = 5), and (d) adolescents with crystalloid restitution (n = 5). Animals were ventilated, the central vessels and ureters were cannulated, and the animals were subjected to a 3-hour, 10 mm Hg CO2 pneumoperitoneum followed by 2-hour resuscitation. Renal perfusion was assessed by fluorescent microspheres and the rate of urine flow was measured. RESULTS: Urine production significantly decreased after insufflation only in the infant crystalloid and adolescent group, but not in controls or infants treated with colloids. In the infant crystalloid group, urine production remained at levels below 20% of baseline throughout the experiment. In this group, the renal perfusion dropped significantly after the beginning of the capnoperitoneum and remained significantly reduced throughout the experiment. CONCLUSION: Our data indicates that capnoperitoneum impairs renal perfusion and urine production in infants. In moderate-pressure capnoperitoneum, this effect cannot be compensated by application of crystalloids but with colloids.

Optimized preoperative fasting times decrease ketone body concentration and stabilize mean arterial blood pressure during induction of anesthesia in children younger than 36 months: a prospective observational cohort study.

BACKGROUND: In pediatric anesthesia, preoperative fasting guidelines are still often exceeded. OBJECTIVE: The objective of this noninterventional clinical observational cohort study was to evaluate the effect of an optimized preoperative fasting management (OPT) on glucose concentration, ketone bodies, acid-base balance, and change in mean arterial blood pressure (MAP) during induction of anesthesia in children. METHODS: Children aged 0-36 months scheduled for elective surgery with OPT (n = 50) were compared with peers studied before optimizing preoperative fasting time (OLD) (n = 50) who were matched for weight, age, and height. RESULTS: In children with OPT (n = 50), mean fasting time (6.0 ± 1.9 h vs 8.5 ± 3.5 h, P < 0.001), deviation from guideline (ΔGL) (1.2 ± 1.4 h vs 3.7 ± 3.1 h, P < 0.001, ΔGL>2 h 8% vs 70%), ketone bodies (0.2 ± 0.2 mmol·l(-1) vs 0.6 ± 0.6 mmol·l(-1) , P < 0.001), and incidence of hypotension (MAP <40 mmHg, 0 vs 5, P = 0.022) were statistically significantly lower and MAP after induction was statistically significantly higher (55.2 ± 9.5 mmHg vs 50.3 ± 9.8 mmHg, P = 0.015) as compared to children in the OLD (n = 50) group. Glucose, lactate, bicarbonate, base excess, and anion gap did not significantly differ. CONCLUSION: Optimized fasting times improve the metabolic and hemodynamic condition during induction of anesthesia in children younger than 36 months of age.

Impact of preoperative fasting times on blood glucose concentration, ketone bodies and acid-base balance in children younger than 36 months: A prospective observational study.

BACKGROUND: In contrast to preoperative fasting guidelines in paediatric anaesthesia, actual fasting times are often too long. OBJECTIVE: The objective of this study was to evaluate the effect of preoperative fasting on glucose concentration, ketone bodies and acid-base balance in children. DESIGN: A prospective, noninterventional, clinical observational study. SETTING: A single-centre trial, study period from June 2014 to November 2014. PATIENTS: One hundred children aged 0 to 36 months scheduled for elective paediatric surgery. MAIN OUTCOME MEASURES: Patient demographics, fasting times, haemodynamic data, glucose and ketone body concentrations, and acid-base parameters after induction of anaesthesia were documented using a standardised case report form. RESULTS: Mean fasting period was 7.8 ± 4.5 (3.5 to 20) h, and deviation from guideline (ΔGL) was 3.3 ± 3.2 (-2 to 14) h. Linear regression showed a significant correlation between fasting times and ketone bodies, anion gap, base excess, osmolality as well as bicarbonate (for each, P < 0.05), but not glucose or lactate. In children with ΔGL more than 2 h (54%), ketone bodies, osmolality and anion gap were significantly higher and base excess significantly lower than children with ΔGL less than 2 h (for each, P < 0.05). CONCLUSION: After prolonged preoperative fasting, children younger than 36 months can present with ketoacidosis and (low) normal blood glucose concentrations. Actual fasting times should be optimised according to existing guidelines. In small infants, deviations from fasting guidelines should be as short as possible and not longer than 2 h.

Comparison of bicarbonate-buffered fluid and isotonic saline solution as Cell Saver washing fluids for packed red blood cells.

OBJECTIVES: Massive transfusion (MT) can cause severe electrolyte and acid-base disturbances in neonates and infants due to the unphysiological composition of packed red blood cells (PRBCs). Washing of the PRBCs using Cell Saver systems prior to MT is recommended for this reason. AIM: The composition of normal saline (NaCl), the standard wash fluid for Cell Saver systems, is considerably different from that of physiological plasma. The aim of the study presented here was to investigate the effect of washing the PRBCs with a bicarbonate-buffered hemofiltration solution (BB-HS) in comparison with washing with NaCl and to evaluate the impact on electrolyte concentrations, acid-base balance and the stability of PRBCs. METHODS: In an experimental in vitro setting, PRBCs were washed with Cell Saver systems prepared with NaCl or BB-HS as washing solutions. Before and after the washing procedure, electrolyte concentrations, acid-base parameters, adenosine triphosphate (ATP) and free hemoglobin (fHb) concentrations were measured. RESULTS: In both groups, the potassium concentrations decreased (baseline: 18.4 ± 5.17 mmol·l(-1), end of study: NaCl 2.71 ± 1,81 mmol·l(-1), BB-HS 2.50 ± 1.54 mmol·l(-1), P < 0.05) while the acid-base balance improved only in the BB-HS-group (baseline: base excess -21.6 ± 3.52 mmol·l(-1), end of study: NaCl -30.2 ± 1.42 mmol·l(-1), BB-HS -7.51 ± 2.49 mmol·l(-1) , P < 0.05). Furthermore, markers of erythrocyte stability such as fHb and ATP concentrations were improved in the BB-HS-group. CONCLUSIONS: Washing of PRBCs with BB-HS rather than NaCl results in a more physiological composition with improvements of electrolyte concentrations, acid-base balance and erythrocyte stability.

First experiences with intraoperative Levosimendan in pediatric cardiac surgery.

Levosimendan is a calcium-sensitizing agent with effective inotropic properties. It has been shown to improve cardiac function, hemodynamic performance, and survival in adults with severe heart failure. However, the effect of Levosimendan in pediatric cardiac surgery has not yet been investigated. Thus, we report on our experience with the intraoperative application of Levosimendan in seven infants (body weight range 2.6-6.3 kg) with severe myocardial dysfunction after complex congenital heart surgery. During the administration of Levosimendan, the heart rate, mean arterial blood pressure, and central venous pressure did not change. The mean arterial lactate level significantly decreased 24 and 48 h after the first infusion compared to baseline. Central venous oxygen saturation increased significantly 24 and 48 h after the onset of Levosimendan infusion. We found intraoperatively administered Levosimendan to be well tolerated in the seven infants with severe myocardial dysfunction after complex congenital heart surgery. Levosimendan is a new rescue drug which has beneficial effects, even in pediatric cardiac surgery.

Plasma volume replacement with HES 130/0.42 obviates negative side effects of pneumoperitoneum in piglets.

BACKGROUND: Evidence-based guidelines on optimal perioperative fluid management in infants have not been established. Recent randomized trials in major abdominal surgery in adults suggest that large volumes of fluid may increase morbidity and hospital stay. Our own clinical experience in infants undergoing laparoscopic surgery is different. So the aim of this study was to compare a crystalloid vs a plasma volume stabilizing fluid management regime during prolonged pneumoperitoneum (PP) in an experimental setting. METHODS: Fifteen German landrace piglets were randomized to one of the following treatment groups: control (no PP, 5 ml x kg(-1) x h(-1) electrolyte solution); crystalloid (180 min of PP, 5 ml x kg(-1) x h(-1) electrolyte solution); colloid (180 min of PP, single bolus of 5 ml x kg(-1) followed by 5 ml x kg(-1) x h(-1) hydroxyethyl starch 130/0.42/6:2). After decompression, monitoring was continued for a further 120 min. During the investigation, the hemodynamic situation including transpulmonary thermodilution and blood gases was monitored periodically. RESULTS: During the study, mean arterial pressure remained within the normal range in colloid-treated animals and controls, but was significantly lower in crystalloid-treated animals after decompression of PP. Cardiac output remained within the normal range in the colloid and control groups, but decreased in the crystalloid-treated animals. In the crystalloid group, the lactate concentrations were higher and base excess was lower than in the colloid and control groups at 240 and 300 min (study end). CONCLUSION: This study shows that the negative effects of prolonged PP on hemodynamics and acid-base balance can be obviated by a liberal plasma volume stabilization regimen with colloids.

Comparison of electrical velocimetry and transpulmonary thermodilution for measuring cardiac output in piglets.

BACKGROUND: Monitoring of cardiovascular function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output (CO) and oxygen delivery is expensive and sometimes associated with adverse events. Therefore, we investigated the accuracy of a new noninvasive CO monitoring device using electrical velocimetry (EV) in comparison with the more invasive transpulmonary thermodilution (TPTD) method. METHODS: In five fasted, anesthetized and mechanically ventilated piglets, CO was measured simultaneously using EV and TPTD under normal conditions, volume loading, inotropic support and exsanguination. RESULTS: In five piglets, 169 measurements could be performed. The correlations between EV-CO and TPTD-CO were significant for absolute values (P < 0.0001, r = 0.82) and relative changes from baseline (P < 0.0001, r = 0.93). The receiver operating characteristic (ROC) curve analysis of the relative changes of the EV-CO values in relation to the first EV-CO measurement showed a sensitivity of 91% and specificity of 94% (AUC 0.974, 95% CI 0.96-0.99). Changes in TPTD-CO greater than 15% lead to a change of EV-CO in the same direction in 93%. Bland-Altman analysis showed a mean difference between the two methods of -0.63 l x min(-1) with an sd of 0.64 l x min(-1). The lower and upper limits of agreement were -1.88 and 0.62 l x min(-1), percentage limit of agreement was +/-82.8%. CONCLUSIONS: The results show that EV is a safe, simple, noninvasive and cost-effective method for continuous trend monitoring of CO in piglets. The agreement of the EV-CO with TPTD-CO is not good enough to replace the standard method in our animal model. A correction factor for body habitus in piglets may be beneficial.

Continuous monitoring of central venous oxygen saturation in neonates and small infants: in vitro evaluation of two different oximetry catheters.

BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function are essential during major pediatric and pediatric cardiac surgery. Monitoring of the central venous oxygen saturation (ScvO(2)) may be a better indicator of tissue oxygenation and derangement of cellular oxygen utilization than the more commonly used vital parameters. Therefore, we compared oxygen saturation measurements with thin fiberoptic oximetry catheters and standard blood gas oximetry in an in vitro setting. METHODS: Two different size continuous fiberoptic oximetry catheters (2-4-F) were inserted in an extracorporeal circuit filled with human red blood cells in normal saline (haematocrit 30%, flow 600 ml.min(-1)). The results of fiberoptic oximetry were then compared with standard blood gas oximetry for a wide range of different oxygen saturations using linear regression. RESULTS: The oxygen saturations found ranged from 9% to 100%. The results of the two different fiberoptic oximetry catheters correlated significantly (r = 0.99, P < 0.0001) with standard blood gas oximetry. CONCLUSION: The results of fiberoptic oximetry are nearly identical with standard blood gas oximetry for a wide range of different oxygen saturations. Thin oximetry catheters can be inserted percutaneously even in neonates and small infants. The continuous monitoring of ScvO(2) may be beneficial, especially in patients who are in danger of developing low cardiac output or sudden cardiovascular collapse.

Correlation of oxygen delivery with central venous oxygen saturation, mean arterial pressure and heart rate in piglets.

BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output and oxygen delivery (DO(2)) is expensive and sometimes associated with adverse events. Measurement of central venous oxygen saturation (ScvO(2)) is less invasive and may reflect the DO(2). Therefore, we investigated the correlation of ScvO(2) with cardiac index (CI) and DO(2) and in comparison the more common monitored parameters heart rate (HR) and mean arterial pressure (MAP) with DO(2) in an animal experimental setting. METHODS: In five fasted, anesthetized and mechanically ventilated piglets CI (transpulmonary thermodilution), venous and arterial blood gases, HR and MAP was measured during normal conditions, volume loading, inotropic support, and exsanguination. RESULTS: In the five piglets 168 measurements could be performed. In a wide hemodynamic range (CI 22-335 ml x kg(-1) min(-1)) we found significant correlations of ScvO(2) with DO(2)) (r(2) = 0.91, P < 0.0001) and CI (r(2) = 0.88, P < 0.0001) and also between DO(2) and MAP (r = 0.86, P < 0.0001) and HR (r = 0.19, P < 0.05). CONCLUSIONS: ScvO(2) is a better parameter for indirect estimation of DO(2) than MAP and heart rate. Measurement of ScvO(2) is simple and does not necessitate additional invasive techniques. In the clinical setting ScvO(2) should be used in combination with other standard vital parameters, i.e. MAP, central venous pressure, lactate, base excess, and urine output.