Arterioportal shunting, splanchnic capillary perfusion, and the effects of colloids during capnoperitoneum in neonatal and adolescent pigs.

BACKGROUND: Clinical and experimental data indicate that neonates are sensitive to the CO2 pneumoperitoneum. An impaired splanchnic perfusion during laparoscopy in adults has been reported. We recently confirmed that intravenous colloids improve macrocirculatory function in neonates. We aimed to determine the impact of CO2 pneumoperitoneum on the perfusion of splanchnic organs in the young including effects of colloid application. METHODS: Male piglets (n = 25) were divided into four groups: (1) neonatal controls, (2) neonates with crystalloid restitution, (3) neonates with colloidal restitution, and (4) adolescents with crystalloid restitution. Animals were ventilated and subjected to a 3-h, 10 mmHg CO2 pneumoperitoneum followed by 2 h resuscitation. Hepatic, splanchnic, and arteriovenous shunt perfusion was assessed via central and portal venous catheters. Capillary organ flow was detected by fluorescent microspheres. The rate of bile flow was measured. RESULTS: The neonatal crystalloid group showed a significant decrease in the intestinal capillary perfusion at the end of the recovery period. This was not detectable in the adolescent and colloid group. There was a significant increase in microcirculatory arterioportal shunt flow during the CO2 pneumoperitoneum in both neonatal groups but not in the sham and adolescent groups (p < 0.05). Hepatic arterial perfusion increased after insufflation in all groups and dropped during capnoperitoneum to levels of about 70% baseline. There was no significant impairment of splanchnic perfusion or bile flow as a result of the pneumoperitoneum in all groups. CONCLUSIONS: Capillary perfusion of the abdominal organs was stable during capnoperitoneum and recovery in adolescents and neonates with colloid restitution, but not with crystalloid restitution. Significant arterioportal shunting during capnoperitoneum could affect hepatic microcirculation in neonates. Our data confirm that moderate pressure capnoperitoneum has no major effect on the perfusion of abdominal organs in neonates with adequate substitution.

Our experience with single lung ventilation in thoracoscopic paediatric surgery.

INTRODUCTION: Data on the feasibility and effects of single lung ventilation (SLV) in children are scarce. We conducted a retrospective study on the feasibility of SLV during video-assisted thoracoscopic surgery (VATS) in children and adolescents undergoing major thoracic procedures. METHODS: A retrospective chart review of all records from patients who underwent VATS at our institution from 2000 to 2010 was done. Patients receiving SLV were analysed in detail. Endpoints of the analysis were conversion to open thoracotomy (frequency and reasons), postoperative duration of ventilation, and pulmonary complications such as radiologically confirmed atelectasis and pneumonia. RESULTS: 74 out of 305 patients (24%, 43 boys, 31 girls) with a mean age of 9.4 years (56 days-18 years) and mean weight of 34 kg (4.5-76 kg) had SLV. Lung resection was done in 43 (58%), pleural surgery in 17 (23%), a combination of both in 7 (9%), and mediastinal procedures in 7 (9%). 11 patients (15%) required conversion of VATS to open surgery, mostly because of problems with exposure of the operative field (73%). 32 patients (43%) were extubated immediately after the operation, whereas 8 (11%) required ventilation for more than 24 h. The mean intensive care unit stay was 1.6 days. 18 patients (24%) developed radiologically confirmed atelectasis, and 1 patient (1%) required bronchoscopic clearance. Pneumonia occurred in 1 case (1%) and was successfully treated with antibiotics. CONCLUSION: SLV is feasible in children and adolescents undergoing VATS for a broad spectrum of procedures. However, despite SLV, the conversion rate in our series was 15%. The main reason for conversion was problems with exposure of the operative field. The complication rate for SLV was low. Atelectasis developed in every fourth patient but usually resolved spontaneously, and intervention to achieve ventilation was rarely indicated.

Cardiovascular responses to prolonged carbon dioxide pneumoperitoneum in neonatal versus adolescent pigs.

BACKGROUND: Long-lasting minimally invasive procedures are increasingly used for children. However, the hemodynamic effects of a prolonged carbon dioxide (CO(2)) pneumoperitoneum (PP) on small infants are poorly understood and may differ from the effects on adolescents. This study aimed to detect and compare these effects in neonatal and adolescent pigs. METHODS: Six neonatal pigs weighing 5.6-6.4 kg and six adolescent pigs weighing 51-57 kg underwent a prolonged CO(2) PP of 180 min. Five neonatal pigs weighing 5.7-6.6 kg underwent sham PP as an additional control group. All the animals received crystalloid electrolyte solution at 10 ml/kg/h during the experiments. After CO(2) decompression, all the animals were monitored for a further 120 min. The end points of the study were mean arterial pressure (MAP), central venous pressure (CVP), and cardiac index (CI). The parameters were assessed after a 60-min resting phase (i.e., after initial placement of catheters in the jugular vein, the carotid artery, and the femoral artery four times during CO(2) PP and three times afterward. RESULTS: The comparison of neonates and adolescent pigs showed that neonates had a significantly more pronounced decrease in MAP during CO(2) PP (88.1 +/- 2.7% of baseline vs 95.1 +/- 1.6%; p < 0.05) and the recovery period (71 +/- 5.1% vs 86.4 +/- 1.4%; p < 0.05). Differences in CVP changes between the neonatal and adolescent pigs during and after CO(2) PP were not significant. For the neonates, the decrease in CI was most pronounced during the recovery period after decompression of the CO(2) PP and significantly less than in adolescents (84.3 +/- 3.3% of baseline vs 97.4 +/- 4.5%; p < 0.05). The neonates with sham PP did not show any significant MAP, CVP, or CI changes during the experiments. CONCLUSIONS: A prolonged CO(2) PP induces hypotension and cardiac depression in neonatal but not in adolescent pigs. Thus, intensive monitoring during prolonged laparoscopic procedures and particularly afterward may be mandatory for neonates.

Penile block is associated with less urinary retention than caudal anesthesia in distal hypospadia repair in children.

BACKGROUND: Caudal anesthesia (CA) is widely recommended due to excellent analgesia in distal hypospadia repairs, but its potential side effect on urinary retention interferes with patient comfort. To objective is to determine the impact of CA versus penile block (PB) on postoperative micturition. METHODS: Sixty distal hypospadia repairs performed over a 48-month period were analyzed concerning the impact of applicated analgesia on postoperative micturition. Inclusion criteria were Mathieu or Snodgrass procedures, use of a non-dribbling urethral stent, CA or PB. Endpoint was first postoperative micturation (<6 h), or treatment of delayed postoperative micturation (>6 h). RESULTS: CA was used in 27 and PB in 33 cases. Compared groups had similar age (mean: 31 months, range 12-68 vs. 28 months, range: 14-145), weight (mean: 13 kg, range 9-18 vs. 15 kg, range 8-59), operation duration (mean 61 min, range 30-105 vs. mean 67 min, range 35-120) and surgical technique (Mathieu/Snodgrass: 7/20 CA vs. 19/14 PB). Micturation was significantly less impaired in the PB than CA group (5/33 vs. 15/27; p < 0.05). Delayed or non-micturation was successfully treated in 4 and 14 patients, respectively, by cholinergic agonists. One patient of each group required a suprapubic drain on the first operative day after unsuccessful medical treatment. CONCLUSIONS: In our series, children undergoing distal hypospadia repair experienced significantly less impaired micturition when using penile block instead of caudal anesthesia. We recommend penile block as the first choice perioperative analgesia, when spontaneous postoperative micturition must be guaranteed.

Bicarbonate-buffered ultrafiltration during pediatric cardiac surgery prevents electrolyte and acid-base balance disturbances.

Pediatric cardiopulmonary bypass is still a challenge because of electrolyte disturbances and inflammation. Many investigations deal with different types of hemofiltration to reduce these potentially harmful side effects. We tested the hypothesis of whether bicarbonate-buffered hemofiltration of the priming solution minimizes electrolyte and acid-base disturbances during the initiation of cardiopulmonary bypass and whether bicarbonate-buffered hemofiltration performed during cardiopulmonary bypass could reduce cytokine levels. Twenty children younger than 2 years of age (mean age 166 +/- 191 days; mean weight 6.42 +/- 3.22 kg) scheduled for pediatric cardiac surgery with cardiopulmonary bypass were enrolled in this prospective clinical study. Cardiopulmonary bypass circuits were primed with a bicarbonate-buffered hemofiltration solution, gelatin and 1 unit of packed red blood cells. The priming was hemofiltered using an ultrahemofilter until approximately 1000 mL of ultrafiltrate was restored with the buffered solution. Further hemofiltration was performed throughout the whole bypass time, especially during rewarming. Blood gas analyses and inflammatory mediators were monitored during the operation. Blood gas analysis results after initiation of cardiopulmonary bypass and throughout the entire study remained within the physiologic ranges. Even potassium decreased from 4.0 +/- 0.3 to 3.4 +/- 0.4 mmol l(-1) after initiation of cardiopulmonary bypass. Plasma levels of tumor necrosis factor alpha decreased significantly (47 +/- 44 vs. 24 +/- 21 pg mL(-1)) whereas complement factor C3a (5.0 +/- 2.9 vs. 16.8 +/- 6.6 ng mL(-1)) and interleukin-6 (7.3 +/- 15.2 vs. 110 +/- 173 pg mL(-1)) increased despite hemofiltration. In conclusion, this study shows that bicarbonate-buffered ultrafiltration is an efficient, simple and safe method for performing hemofiltration, both of the priming solution and during the entire bypass time. The use of a physiological restitution solution prevents electrolyte and acid-base balance disturbances. The elimination of inflammatory mediators seems to be as effective as other ultrafiltration methods.

Equal effects of gelatin and hydroxyethyl starch (6% HES 130/0.42) on modified thrombelastography in children.

BACKGROUND: Artificial colloids are frequently used to prevent or treat circulatory failure due to hypovolaemia. Whereas gelatin has been shown not to affect coagulation besides its haemodilutional effect, hydroxyethyl starches (HES) have additional negative effects on haemostasis. The third-generation HES solutions have been developed to minimise these effects. We therefore conducted a prospective, randomised study, to verify the hypothesis that a 6% HES 130/0.42/6 : 1 and a 4% gelatin infusion influences modified thrombelastography (TEM) parameters in children in the same manner and to the same extent. METHODS: A total of 50 paediatric patients aged 0-12 years scheduled for surgery were assigned to receive either 10 ml/kg HES 130/0.42 or gelatin. Blood gas analysis, haemodynamic parameters and TEM measurements were performed before and after colloid administration. RESULTS: Patient characteristics, indications/surgical procedures and the main results obtained from blood gas analysis were comparable between the two groups. After administration of either gelatin or HES, all TEM parameters, except for clotting time, indicated impaired coagulation whereas the mean values of all TEM parameters remained within the normal ranges. Comparing the gelatin and HES 130/0.42/6 : 1 groups, none of the measured TEM parameters was found to show between-group differences at baseline or after colloid infusion. CONCLUSION: In conclusion, we could demonstrate that the investigational product, HES 130/0.42/6 : 1 solution, administered at a dosage of 10 ml/kg to children, had comparable effects on coagulation monitored with TEM as a gelatin solution. Perioperative administration of HES 130/0.42/6 : 1 does not alter coagulation to an extent above and beyond the effect of haemodilution.