Physiological responses to endoscopic surgery in children

Evaluation of renal oxygenization in laparoscopic pediatric surgery by near infrared spectroscopy

PURPOSE

Increased intraabdominal pressure IAP may reduce renal blood flow (RBF). The study aims to evaluate the pneumoperitoneum effect on RBF by comparing renal regional oxygen saturation index (rSrO2) measured by near-infrared spectroscopy (NIRS) in pediatric patients having laparotomy and laparoscopy.

METHODS

Of 58 patients having laparoscopy and laparotomy, 18 were excluded due to renal pathologies, combined open surgical procedures, and administration of inotropic drugs. Hemodynamic parameters and rSrO2 were recorded in laparoscopy (n = 20) and laparotomy (n = 20) groups before induction and with 5 min intervals up to 60 min and at post-extubation.

RESULTS

Decrease in right renal rSrO2 at 45th and 60th min and 30th, 45th and 60th min in left were significant in the laparoscopy group compared to laparotomy group. In the laparoscopy group, reductions at T25, T30, T45, and T60 were significant in both renal rSrO2. Renal rSO2 increased to normal with desufflation.

CONCLUSION

IAP with pneumoperitoneum may lead to renal hypoxia in children. Renal rSO2 returns to normal with desufflation. Renal NIRS monitorization might be needed in patients with renal parenchymal and vascular pathologies, solitary kidney, and multiorgan pathologies that may affect renal oxygenation.

A Prospective Randomized Controlled Trial of Single-Port and Three-Port Laparoscopic Appendectomy in Children

Background: This study aimed to evaluate single-port laparoscopic appendectomy (SPLA) in comparison with three-port laparoscopic appendectomy (3PLA) in children about the extent of surgical trauma after SPLA and 3PLA measured by serum interleukin-6 (IL-6) and C-reactive protein (CRP) concentrations. Materials and Methods: A total of 50 patients with a median age of 11.5 were randomized to two groups. Experts in both methods performed the surgeries. The decision on the type of planned surgery was randomly determined. Serum IL-6 and CRP levels were measured using an enzyme-linked immunosorbent assay before, and at 12 and 36 hours after surgery. Furthermore, we compared operating time, hospital stay, postoperative pain, and complication rates. Results: The operative time in the 3PLA group was shorter than that in the SPLA group (P < .05). Preoperative IL-6 levels were not different between the two groups, but the rise (pre- versus postoperative) of IL-6 in the SPLA group was remarkably higher when compared with the 3PLA group (P < .05). Similar results were obtained for CRP; basal serum CRP levels were not different between the two groups, but the rise of CRP in the 3PLA group was significantly lower compared with that in the SPLA group. During the first 12 hours postoperative, the SPLA patients reported more severe postoperative pain and longer inpatient opiate usage was noted that after 3-PLA. Only one SPLA case was converted to 3PLA. There were no conversions to open surgery. The length of hospital stay and complication rate were not different between the two groups. Conclusions: SPLA in children is associated with longer operative times, increased pain level, and more severe surgical trauma as measured by postoperative CRP and IL-6 levels in comparison with a 3PLA. The two approaches were comparable regarding the length of hospital stay and complication rate.

Advanced minimal access surgery in infants weighing less than 3kg: A single center experience

BACKGROUND

Minimal access surgery (MAS) has gained popularity in infants less than 5kg, however, significant challenges still arise in very low weight infants.

STUDY DESIGN

A retrospective chart review was performed to identify all infants weighing less than 3kg who underwent an advanced MAS or equivalent open procedure from 2009 to 2016. Advanced case types included Nissen fundoplication, duodenal atresia repair, Ladd procedure, congenital diaphragmatic hernia repair, esophageal atresia/tracheoesophageal fistula repair, diaphragmatic plication, and pyloric atresia repair. A comparative analysis was performed between the MAS and open cohorts.

RESULTS

A total of 45 advanced MAS cases and 17 open cases met the inclusion criteria. Gestational age and age at operation were similar between the cohorts, while infants who underwent open procedures had significantly lower weight at operation (p=0.003). There were no deaths within 30days related to surgery in either group. Only 3 MAS cases required unintended conversion to open. There were 2 (4.4%) postoperative complications related to surgery in the MAS cohort and 2 (11.8%) in the open cohort.

CONCLUSION

Advanced MAS may be performed in infants weighing less than 3kg with low mortality, acceptable rates of conversion, and similar rates of complications as open procedures.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

Level III.

Pneumoperitoneum and hemodynamic stability during pediatric laparoscopic appendectomy

BACKGROUND

Conventional pneumoperitoneum (CP) and automatically maintained pneumoperitoneum using AirSeal Intelligent Flow System (AiFS) were compared during pediatric laparoscopic appendectomy (LA) using intraperitoneal pressure (IPP) and hemodynamic parameters.

METHODS

A prospective review of 39 children aged 3-14years who had standard 3-trocar LA was performed. Pneumoperitoneum was either AiFS (n=18) or CP (n=21) according to the surgeon's preference. IPP during insertion of trocars in all subjects was initially 8-10mmHg, which was reduced to 5mmHg then maintained until LA was completed. Data were collected every 5min during pneumoperitoneum.

RESULTS

Subject demographics were similar for both groups. During pneumoperitoneum, average IPP (AiFS: 7.9; CP: 9.0mmHg), average systolic blood pressure (AiFS: 100.4; CP: 106.9mmHg), and average end-tidal CO₂ (EtCO₂; AiFS: 35.7; CP: 38.5mmHg) were significantly different (p<.05, respectively), while pulse (AiFS: 92.1; CP: 96.4bpm), oxygen saturation (AiFS: 98.8; CP: 98.8%), body temperature (AiFS: 37.2; CP: 37.4), urine output (AiFS: 2.7; CP: 2.4mL/kg per hour), operative time (AiFS: 72.2; CP: 76.2mins), blood loss (AiFS: 3.6; CP: 3.5mL), recommencement of oral intake (AiFS: 1.3; CP: 1.4days), and postoperative hospitalization (AiFS: 4.3; CP: 3.8days) were not.

CONCLUSION

Because IPP was significantly lower during LA with AiFS, EtCO₂ and BP were significantly lower.

LEVEL OF EVIDENCE

Treatment study; prospective comparative study - level II.

Flexible ureteroscopic lithotripsy for the treatment of upper urinary tract calculi in infants

We evaluated the clinical value of flexible ureteroscopic lithotripsy for the treatment of upper urinary tract calculi in infants. Fifty-five infants with upper urinary tract calculi were included in this study: 41 males and 14 females. Retrograde intrarenal surgery was performed by an 8 Fr/30 cm flexible ureterorenoscope (POLY®) combined with a holmium laser. CT scanning or radiography of the kidneys, ureters, and bladder region was performed one month after the operation to confirm the clearance of calculi. All the 55 infants with calculi in 74 sides underwent 66 flexible ureteroscopic lithotripsy procedures. The median operation time was 30 min. The median amount of flushing fluid was 500 mL. The stone-free rate after a single session treatment was 94.6%, within which 10 infants underwent simultaneous bilateral flexible ureteroscopy lithotripsy. Catheters were retained in 45 infants for 24-48 h after the operation. Continuous high fever due to reflux was present in two cases. Flushing fluid extravasation was found in one infant. Some patients with minor complications, such as mild hematuria, irritation symptoms, and low fever, recovered without treatment. The duration of hospitalization time after the operation was approximately 1-5 days. Flexible ureteroscopic lithotripsy is a safe, highly efficient, minimally invasive, and reproducible operation for removal of upper urinary tract calculi in infants. This technique is a convenient method for postoperative management of patients that enhances their rapid recovery. It is a promising option for therapy of infants ineffectively treated by extracorporeal shockwave lithotripsy.

Thoracoscopic versus open repair of CDH in cardiovascular stable neonates

Background

Thoracoscopic surgery is an increasingly popular surgical technique to repair congenital diaphragmatic hernia (CDH). However, acidosis during surgery and the higher recurrence rate are considerable risk factors. The aim of this retrospective study is to compare the outcome of open versus thoracoscopic repair of the diaphragm in neonates with CDH with the same degree of cardiovascular and pulmonary illness who meet the criteria for thoracoscopic repair.

Methods

Retrospective analysis of all patients of two large national reference centers for CDH born in the years 2008 through 2012, and meeting the criteria for surgical repair on cardiopulmonary and physiological criteria according to the CDH EURO consortium consensus and meeting the criteria for thoracoscopic repair according to the review by Vijfhuize et al. The surgical technical aspects were comparable in both centers.

Results

108 patients were included, of whom 75 underwent thoracoscopic repair and 34 underwent open repair. The gestational age and lung-to-head ratio were significantly lower and stay on the ICU significantly longer in the open-repair group. The operation time was longer (178 vs. 150 min, p = .012) and the recurrence rate higher (18.9 vs. 5.9 %, p = .036) in the thoracoscopic-repair group. The arterial pH, pO₂, pCO₂ and base excess before and after thoracoscopic repair were all significantly different.

Conclusion

After critical selection for thoracoscopic repair of left-sided CDH based on the patient’s preoperative condition, the outcomes of open repair were almost identical to those of thoracoscopic repair. A notable exception is the recurrence rate, which was significantly higher in the thoracoscopic-repair group. For the time being, thoracoscopic primary closure seems a safe and effective procedure, but efficacy of thoracoscopic patch repair has not been established.

Optimizing working space in laparoscopy: CT measurement of the influence of small body size in a porcine model

INTRODUCTION

In our continuing research into the determinants of laparoscopic working space, the influence of small body size was investigated.

METHODS

In eight 6-kg pigs, the effects of intraabdominal CO2 pneumoperitoneum pressure (IAP), prestretching of the abdominal wall, and neuromuscular blockade (NMB) on laparoscopic working space volume and distances were studied. Computed tomography was used to measure working space during two stepwise abdominal insufflation-runs up to an IAP of 15mm Hg. Results were compared with data from earlier experiments in 20-kg pigs.

RESULTS

Cardiorespiratory parameters were stable up to an IAP of 8-10mm Hg. In 6-kg pigs working-space dimensions were five times smaller than in 20-kg pigs. Working-space volume, anteroposterior (AP) diameter and symphysis-diaphragm distance increased linearly up to an IAP of 8mm Hg. Above 8mm Hg, compliance decreased. Eighty percent of the total volume (618ml) and of AP diameter (3cm) at 15mm Hg had been achieved at an IAP of 10mm Hg. Prestretching by a first insufflation resulted in a statistically significant increase in working space volume and in AP diameter during the second insufflation. This effect was significantly larger than in 20-kg pigs. Neuromuscular blockade did not have a significant effect on working-space.

CONCLUSIONS

Working space in growing individuals is very limited. Eighty percent of the working space created by an IAP of 15mm Hg was already achieved at 10mm Hg, while cardiorespiratory side effects at an IAP of 8-10mm Hg seem acceptable. Prestretching of the abdominal wall significantly increased working space, even more so than in 20-kg pigs. As in 20-kg pigs, NMB had no significant effect on laparoscopic working space. Prestretching of the abdominal wall is a promising cheap, safe and easy strategy to increase laparoscopic working space, lessening the need for prolonged high-pressure pneumoperitoneum.

Does pneumoperitoneum adversely affect growth, development and liver function in biliary atresia patients after laparoscopic portoenterostomy?

PURPOSE

We assessed the effect of high partial pressure of arterial carbon dioxide (PaCO2) due to pneumoperitoneum (PP) on growth (height/weight) and development (gross/fine motor function, receptive/expressive communication, and social interaction), by comparing outcome after portoenterostomy (PE) for biliary atresia (BA) using laparoscopic PE (LPE: n = 13) and open PE (OPE: n = 13) cases performed between 2005 and 2014.

METHODS

Our PE is based on Kasai's original PE. All data were collated prospectively.

RESULTS

Differences in duration of follow-up (LPE: 38.8 months; OPE: 38.1 months), jaundice clearance (LPE: 12/13 = 92.3 %; OPE: 9/13 = 69.2 %), survival with the native liver (LPE: 10/13 = 76.9 %; OPE: 9/13 = 69.2 %), incidence of cholangitis, hypersplenism, and incidence of esophageal varices were not significant. Mean intraoperative PaCO2 was significantly higher in LPE (LPE: 50.1 mmHg; OPE: 40.7 mmHg, p < 0.05). Liver function impairment was not statistically different, although LPE results were slightly worse. There was no overall delay in growth observed, although height/weight gain was more consistent in LPE. The pattern of developmental delay observed was similar for LPE and OPE suggesting that developmental delay is not PE-related; in other words, PP is not implicated in developmental delay.

CONCLUSIONS

PP during LPE would appear to have no adverse effects on overall growth/development and liver function in BA patients.

Minimal invasive surgery in the newborn: current status and evidence

The evolution of minimally invasive surgery (MIS) in the newborn has been delayed due to the limited working space and the unique physiology. With the development of smaller instruments and advanced surgical skills, many of the initial obstacles have been overcome. MIS is currently used in specialized centers around the world with excellent feasibility. Obvious advantages include better cosmesis, less trauma, and better postoperative musculoskeletal function, in particular after thoracic procedures. However, the aim of academic studies has shifted from proving feasibility to a critical evaluation of outcome. Prospective randomized trials and high-level evidence for the benefit of endoscopic surgery are still scarce. Questions to be answered in the upcoming years will therefore include both advantages and potential disadvantages of MIS, especially in neonates. This review summarizes recent developments of MIS in neonates and the evidence for its use.

Inflammatory response after open and laparoscopic Nissen fundoplication in children: a randomized study

PURPOSE

It is assumed that laparoscopic surgery generally induces less inflammatory responses than open surgery. Since few studies have compared immune responses after laparoscopic and open surgery in children, we examined inflammatory markers in children randomized to open (ONF) or laparoscopic Nissen fundoplication (LNF).

METHODS

Blood samples were collected prior to surgery (D0), and on postoperative day 1 (D1) and day 2 (D2). Inflammatory markers were measured using a multiplex antibody bead kit. The postoperative levels of inflammatory markers were statistically analyzed using a linear mixed model. A P value <0.05 was considered statistically significant.

RESULTS

Twenty-nine patients randomized to ONF or LNF were included. Median age was 3.1 years (range 1.0-14.2) in the ONF group and 4.0 years (range 0.2-14.2) in the LNF group. Plasma levels of the anti-inflammatory cytokine interleukin (IL)-10 were significantly higher in the ONF group than in the LNF group postoperatively (P = 0.04). However, there were no significant differences between the groups in the levels of pro-inflammatory markers tumor necrosis factor-α, IL-6, IL-8, monocyte chemoattractant protein-1, white blood cell count, or C-reactive protein.

CONCLUSIONS

We did not find that laparoscopy induced a substantially less inflammatory response than laparotomy in children undergoing fundoplication.

Epidermal growth factor and monocyte chemotactic peptide-1: potential biomarkers of urinary tract obstruction in children with hydronephrosis

OBJECTIVE

Hydronephrosis is diagnosed in 0.5% of all newborns, and ureteropelvic junction obstruction (UPJO) is a common cause. The aim of this study was to test whether specific urinary cytokines can be used as UPJO biomarkers in children with hydronephrosis.

MATERIALS AND METHODS

Twenty-eight children referred for pyeloplasty due to UPJO and 13 controls were included in this prospective study. Kidney function was assessed and urine samples collected pre-, peri-, and post-operatively. Urine levels of epidermal growth factor (EGF), monocyte chemotactic peptide-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), interferon-γ-inducible protein-10 (IP-10), and RANTES were measured simultaneously by using a bead-based multiplex sandwich immunoassay.

RESULTS

In hydronephrotic children, preoperative urine levels were significantly increased for EGF (median 7.4 [1.2-60.2] vs. median 4.0 [1.2-13.8] ng/mg creatinine) and MCP-1 (median 136.9 [47.7-545.5] vs. median 80.1 [28.8-149.9] pg/mg creatinine) compared to those of controls. Urine levels of EGF and MCP-1 were identical to controls at the postoperative 1-year follow-up exam.

CONCLUSION

Urine levels of EGF and MCP-1 were preoperatively increased and postoperatively normalized. This study demonstrates that urine-excreted kidney cytokines may be potential biomarkers of obstruction in children with hydronephrosis.

Optimizing working space in laparoscopy: CT measurement of the effect of pre-stretching of the abdominal wall in a porcine model

BACKGROUND

Determinants of working space in minimal access surgery have not been well studied. Using computed tomography (CT) to measure volumes and linear dimensions, we are studying the effect of a number of determinants of CO2 working space in a porcine laparoscopy model. Here we report the effects of pre-stretching of the abdominal wall.

METHODS

Earlier we had noted an increase in CO2 pneumoperitoneum volume at repeat insufflation with an intra-abdominal pressure (IAP) of 5 mmHg after previous stepwise insufflation up to an IAP of 15 mmHg. We reviewed the data of this serendipity group; data of 16 pigs were available. In a new group of eight pigs, we also explored this effect at repeat IAPs of 10 and 15 mmHg. Volumes and linear dimensions of the CO2 pneumoperitoneum were measured on reconstructed CT images and compared between the initial and repeat insufflation runs.

RESULTS

Previous stepwise insufflation of the abdomen with CO2 up to 15 mmHg significantly (p < 0.01) increased subsequent working-space volume at a repeat IAP of 5 mmHg by 21 %, 7 % at a repeat IAP of 10 mmHg and 3 % at a repeat IAP of 15 mmHg. The external anteroposterior diameter significantly (p < 0.01) increased by 0.5 cm (14 %) at repeat 5 mmHg. Other linear dimensions showed a much smaller change. There was no statistically significant correlation between the duration of the insufflation run and the volume increase after pre-stretching at all IAP levels.

CONCLUSIONS

Pre-stretching of the abdominal wall allows for the same surgical-field exposure at lower IAPs, reducing the negative effects of prolonged high-pressure CO2 pneumoperitoneum on the cardiorespiratory system and microcirculation. Pre-stretching has important scientific consequences in studies addressing ways of increasing working space in that its effect may confound the possible effects of other interventions aimed at increasing working space.

Warm, humidified carbon dioxide gas insufflation for laparoscopic appendicectomy in children: a double-blinded randomized controlled trial

OBJECTIVE

To investigate clinical benefits of warm, humidified carbon dioxide (CO(2)) insufflation for acute laparoscopic appendicectomy on postoperative pain and recovery in children (age 8-14 years).

BACKGROUND

Conventional CO(2) insufflation leads to desiccation-related peritoneal inflammation and injury, which is preventable with warm, humidified CO2 gas. We hypothesized that reduced peritoneal desiccation would improve patient-centered outcomes in children after laparoscopic appendicectomy.

METHOD

A double-blinded, randomized controlled trial was conducted. Intervention group participants received warm (37°C), humidified (98% relative humidity) CO(2) gas insufflation, whereas control participants received standard room temperature (20°C) gas with 0% relative humidity. Perioperative analgesia and anesthesia were standardized. Postoperative opiate usage was converted to morphine equivalent daily dosages (MEDD) for comparison, and pain intensity at rest and on moving was rated by participants using visual analog scales. Postoperative recovery and return to normal activities was assessed using a questionnaire on day 10.

RESULTS

Between February 2010 and March 2011, a total of 190 participants were randomized. Both intervention and control groups were matched at baseline. Postoperative MEDD and pain scores were also similar. There were no differences in postoperative recovery parameters.

CONCLUSIONS

Warm, humidified CO(2) insufflation for acute laparoscopic appendicectomy has no short-term clinical benefits on postoperative outcomes in pediatric patients (ClinicalTrials.gov trial identifying code: NCT01027455).

Optimizing working-space in laparoscopy: measuring the effect of mechanical bowel preparation in a porcine model

BACKGROUND

Adequate working space is a prerequisite for safe and efficient minimal access surgery. No objective data exist in literature about the effect of mechanical bowel preparation (MBP) on working space in laparoscopic surgery. We objectively measured this effect with computed tomography in a porcine laparoscopy model.

METHODS

Using standardized anesthesia, twelve 20-kg pigs without MBP and eight 20-kg pigs with MBP were studied with computed tomography at intra-abdominal pressure (IAP) levels of 0, 5, 10, and 15 mmHg. Volumes and dimensions of the pneumoperitoneum were measured on reconstructed CT images and compared between the pigs with and those without MBP.

RESULTS

A reproducible and statistically significant increase of approximately 500 ml in pneumoperitoneum volume was found in the MBP group at all levels of IAP. This represents a 43 % relative increase at a pneumoperitoneum pressure of 5 mmHg, 21 % at IAP 10 mmHg, and 18 % at IAP 15 mmHg. Peak inspiratory pressure was lower at IAP 0 and 5 mmHg in the MBP group. Anteroposterior diameter in the group with MBP was lower at 0 mmHg, but abdominal dimensions were similar in both groups at all other IAPs. This shows that the gain in working space is due to a diminished volume of the intra-abdominal content and not to compression or displacement of the bowel.

CONCLUSIONS

MBP increases working space by reducing bowel content. Especially at low intra-abdominal working pressures, the increase in working space associated with MBP could represent an important benefit in challenging laparoscopic surgery.

Enthusiasm, evidence and ethics: the triple E of minimally invasive pediatric surgery

Minimally invasive techniques are applicable in more than 60% of abdominal and thoracic operations in children. Enthusiasts promoted these techniques for many years. However, level 1 evidence on advantages of minimally invasive surgery in children remains limited. Randomized controlled trials have been conducted for some types of procedures such as laparoscopic appendectomy, fundoplication, pyloromyotomy, and inguinal hernia repair. The results of these studies confirm some advantages of minimally invasive surgery, but for most types of laparoscopic and all types of thoracoscopic procedures, such data remain to be established. This article also focuses on reports on complications and disadvantages which are relevant for final conclusions and recommendations. The ethical implications of the application of new techniques in children are also discussed. On the basis of evidence based data and ethical principles, minimally invasive techniques may be appropriately used in the future.

Optimizing working space in porcine laparoscopy: CT measurement of the effects of intra-abdominal pressure

BACKGROUND

Several factors may affect volume and dimensions of the working space in laparoscopic surgery. The precise impact of these factors has not been well studied. In a porcine model, we used computed tomographic (CT) scanning for measuring working space volume and distances. In a first series of experiments, we studied the relationship between intra-abdominal pressure (IAP) and working space.

METHODS

Eleven 20 kg pigs were studied under standardized anesthesia and volume-controlled ventilation. Cardiorespiratory parameters were monitored continuously, and blood gas samples were taken at different IAP levels. Respiratory rate was increased when ETCO₂ exceeded 7 kPa. Breath-hold CT scans were made at IAP levels of 0, 5, 10, and 15 mmHg. Insufflator volumes were compared to CT-measured volumes. Maximum dimensions of pneumoperitoneum were measured on reconstructed CT images.

RESULTS

Respiratory rate had to be increased in three animals. Mild hypercapnia and acidosis occurred at 15 mmHg IAP. Peak inspiratory pressure rose significantly at 10 and 15 mmHg. CT-measured volume increased relatively by 93 % from 5 to 10 mmHg IAP and by 19 % from 10 to 15 mmHg IAP. Comparing CT volumes to insufflator volumes gave a bias of 76 mL. The limits of agreement were -0.31 to +0.47, a range of 790 mL. The internal anteroposterior diameter increased by 18 % by increasing IAP from 5 to 10 mmHg and by 5 % by increasing IAP from 10 to 15 mmHg. At 15 mmHg, the total relative increase of the pubis-diaphragm distance was only 6 %. Abdominal width did not increase.

CONCLUSIONS

CT allows for precise calculation of the actual CO₂ pneumoperitoneum volume, whereas the volume of CO₂ released by the insufflator does not. Increasing IAP up to 10 mmHg achieved most gain in volume and in internal anteroposterior diameter. At an IAP of 10 mmHg, higher peak inspiratory pressure was significantly elevated.

Urinary NGAL, cystatin C, β2-microglobulin, and osteopontin significance in hydronephrotic children

BACKGROUND

Ureteropelvic junction obstruction (UPJO) accounts for 35 % of all congenital hydronephrosis cases. The challenge in managing childhood hydronephrosis is to distinguish obstructive from nonobstructive cases and, thereby, identify patients requiring surgical intervention. This study aimed to examine four urinary proteins as potential biomarkers of obstruction in hydronephrosis.

METHODS

Urine samples from 24 children with UPJO were collected pre-, peri-, and postoperatively, together with urine samples from healthy children. Neutrophil gelatinase-associated lipocalin (NGAL), cystatin C (CyC), β2-microglobulin (β2-M), and osteopontin (OPN) in the samples were measured simultaneously using multiplex sandwich immunoassay technology.

RESULTS

Compared with controls, NGAL and β2-M were significantly increased in urine from patients with obstructed kidneys at the time of surgery. This increase was followed by a decrease and stabilization to the same level as that of the controls. Furthermore, age was negatively correlated with preoperative urinary concentrations of CyC, β2-M, and OPN.

CONCLUSIONS

This study confirms increased concentrations of NGAL and β2-M in urine from obstructed kidneys and should be tested in larger studies to ascertain their ability to identify obstruction and to determine the importance of age-adjusted reference values.

Kidney safety during surgical pneumoperitoneum: an experimental study in rats

BACKGROUND

Elevations of intraabdominal pressure during laparoscopic procedures may lead to oliguria or anuria in mammals. Despite this, previous research has not been able to confirm an associated kidney injury. This study aimed to investigate the occurrence of an early kidney lesion secondary to surgical pneumoperitoneum in a rat model using the expression of neutrophil gelatinase-associated lipocalin (N-GAL) as a biomarker for early kidney injury.

METHODS

In this study, 20 male Sprague-Dawley rats under general anesthesia and mechanically ventilated were allocated to one of five experimental time-dependent groups: group 1 (1-h control), group 2 (1-h pneumoperitoneum), group 3 (2-h control), group 4 (2-h pneumoperitoneum), and group 5 (positive kidney injury group induced by intravenous administration of cisplatin 7.5 mg/kg). To evaluate the renal expression of N-GAL 24 h after the procedure, all the rats underwent a 2-h urine output evaluation as well as laparotomy and bilateral nephrectomy performed sequentially to investigate the presence of renal injury using immunofluorescence qualification and western blotting.

RESULTS

Urine output was reduced and N-GAL expression was increased in the animals from the cisplatin group. The animals undergoing 1- or 2-h pneumoperitoneum displayed urine output and N-GAL expression similar to that of the animals from the matching control groups.

CONCLUSIONS

Under the experimental conditions of this study, the animals with normal preoperative renal function did not show any type of acute kidney injury associated with the presence of a stabilized surgical pneumoperitoneum.

Physiological impact of pneumoperitoneum on gastric mucosal CO2 pressure during laparoscopic versus open appendectomy in children

INTRODUCTION

Funded knowledge about the physiological impact of laparoscopic surgery in children is sparse. Although there are data on hemodynamic compromise after creation of a pneumoperitoneum in children, little is known about microcirculatory changes at the mucosa level. Therefore, the aim of this study was to assess gastric microcirculation by continuous gastric air tonometry in the setting of laparoscopic versus open appendectomy.

PATIENTS AND METHODS

Twenty children 5-17 years old undergoing laparoscopic and 7 children undergoing open appendectomy were included in the study. Gastric intramucosal CO(2) pressure (pCO(2)i) was measured under standardized flow and intraperitoneal pressure using continuous air tonometry (TONOCAP(®), Datex Ohmeda), and ΔpCO(2) (pCO(2)i - end-expiratory CO(2) pressure [pCO(2)e]) was obtained for the time course of surgery.

RESULTS

ΔpCO(2) increased significantly from the baseline value not only in the laparoscopic group but also in the open surgery group. Even though ΔpCO(2) was higher in the laparoscopic group at all time points, the overall increase in ΔpCO(2) for both groups was uniform. The largest differences were observed during the initial 20 minutes of the operation. The changes observed were exclusively due to an increase of pCO(2)i in relation to a constant pCO(2)e.

DISCUSSION

In the setting of a standardized, simple operation in an otherwise healthy child above the age of 5 years, our data suggest that the effect of a pneumoperitoneum on splanchnic perfusion is comparable to the compromise caused by open surgery. Further research must be obtained when evaluating the full impact of laparoscopy in children.

Evaluation of a simple valve mechanism used to stabilize intraabdominal pressure during surgically induced pneumoperitoneum in small animals

BACKGROUND

Preventing sudden changes in intraabdominal pressure (IAP) during surgical pneumoperitoneum may reduce adverse events. This study aimed to describe a valve system that stabilizes intraabdominal pressure, minimizing complications of erratic fluctuations in IAP.

METHODS

Five male Sprague-Dowley rats were submitted to pneumoperitoneum, with the insufflator set sequentially at 5, 10, and 15 mmHg for each rat. Measures of IAP were taken initially without the valve and then using the same insufflator levels with the valve system regulated to three different pressures (5, 10, and 15 mmHg). The mean of the three highest registered pressures during a 15-min observation was used as the maximal pressure, and the mean of the three lowest registered pressures was used as the minimal pressure for each experimental setting.

RESULTS

Without the valve system, the pressure level set by the insufflator correlated poorly with the actual IAP. When the valve system was used, the IAP pressure was limited by the valve settings regardless of the insufflator settings. Also, the variability of IAP was significantly higher when no valve was used than in all situations that had implementation of the system.

CONCLUSIONS

The valve system was very effective in stabilizing IAP, allowing a reproducible and reliable estimate of IAP and greatly reducing the variability resulting from the cycling mechanism of the insufflator. Due to the small dimensions of intracorporeal cavities in the newborn, this mechanism may help to improve safety when neonatal video-assisted surgery is performed.

Minimally invasive surgery in the neonate

The advent of minimally invasive surgical techniques in the neonate has been delayed due to the limited working space and the unique physiology of the newborn. In the last decade, with the introduction of new instruments and techniques, many of the initial problems have been solved making minimally invasive surgery feasible for a variety of indications in the neonate and a favored approach in specialized centers around the world. Although an increasing number of reports document the feasibility of this exciting technique, data demonstrating its benefit compared to conventional surgery is limited. This review focuses on recent developments in minimally invasive surgery in neonates and the evidence for its use.

Increased susceptibility to liver damage from pneumoperitoneum in a murine model of biliary atresia

HYPOTHESIS

We hypothesized that livers with biliary atresia (BA) are more susceptible to the harmful effects of a high-pressure CO(2) pneumoperitoneum (PP) than healthy livers.

METHODS

A murine model of BA was used in this experiment. Mice were divided into 6 groups: (1) control Balb/c; (2) control Balb/c, CO(2)-PP; (3) control BA; (4) BA-sham; (5) BA, CO(2)-PP; and (6) BA, air-PP. Mice from groups 2, 5, and 6 underwent an 8-mm Hg-PP for 60 minutes. Liver samples were collected for histology, colorimetry, and flow cytometry analysis 18 to 24 hours after the procedure. Markers of apoptosis were investigated as indicators of acute cell damage.

RESULTS

We observed a statistically significant higher rate of apoptosis in livers with BA exposed to a prolonged CO(2)-PP or air-PP compared with control groups. There were no significant differences between groups 1 and 2, or between groups 5 and 6.

CONCLUSIONS

In this animal model, we have shown that livers with BA are more susceptible than healthy livers to injury by a prolonged PP. This injury was caused by both CO(2) and air-PP, implying that it is the direct result of pressure. These results may have implications for the success of minimally invasive Kasai procedures.

[Minimally invasive pediatric surgery]

In recent years minimally invasive surgical techniques in children have made substantial progress. The feasibility and safety of a wide spectrum of laparoscopic and thoracoscopic procedures have been confirmed in numerous studies. Moreover, it was reported that minimally invasive pediatric surgery is associated with lower morbidity, a shorter hospital stay, lower costs, better cosmetics and clinical results similar to those achieved by open surgery. The present article reviews information on established as well as feasible but not yet established surgical procedures. The discussion of potential hemodynamic, respiratory and organ perfusion effects of the CO(2) pneumoperitoneum and the notation of special logistic aspects should support the reader in the process of decision-making to schedule infants and children for minimally invasive surgery.

Carbon dioxide does not affect the methylation status of prognostic important oncogenes Rassf1A and DCR2 in neuroblastoma cells

PURPOSE

The aim of the current study was to investigate effects of CO(2) atmosphere, mimicking conditions of the pneumoperitoneum during laparoscopy, on epigenetic conditions of Rassf1A and DCR2 oncogenes in neuroblastoma cells.

METHODS

SH-SY5Y neuroblastoma cells were exposed to 100% CO(2) for 4 h. Cells were lysed 4, 8 and 168 h after exposure. After methylation analysis of Rassf1A and DCR2 with polymerase chain reaction, results were compared to those of physiologically incubated neuroblastoma cells.

RESULTS

No significant changes were found after exposure to carbon dioxide compared to the control. Values of methylated Rassf1A were 12.6 +/- 1.1 versus 13.2 +/- 1.4 ng/microl in the controls, respectively (4 h after incubation), 12.6 +/- 1.2 versus 15.1 +/- 0.9 ng/microl (8 h) and 14.2 +/- 1.5 versus 11.7 +/- 1.3 ng/microl (168 h). DCR2 showed values of 4.6 +/- 0.5 versus 3.7 +/- 0.5 ng/microl (4 h), 3.8 +/- 0.5 versus 4.1 +/- 0.4 ng/microl (8 h) and 3.6 +/- 0.4 versus 3.8 +/- 0.5 ng/microl (168 h).

CONCLUSION

Exposure of neuroblastoma cells to 100% CO(2) does not alter methylation of two prognostic relevant index genes. It seems therefore unlikely that effects on methylation levels within CO(2) pneumoperitoneum lead to epigenetic changes in neuroblastoma.

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.