Abdominal compartment syndrome in childhood: the role of near infrared spectroscopy for the early detection of the organ dysfunction

We found very interesting the manuscript written by Dr. Steinau et al. [1] recently published in your journal. The author proposed their approach for the management of abdominal compartment syndrome (ACS) in childhood presenting a wide case mix of pathology ranging from neonates to school children. We agree that the gold standard for the indirect intrabdominal preassure (IAP) measurement both in adults and children is the intra-bladder pressure monitoring with an intermittent saline bolus. In accordance with the adult guidelines, intrabdominal hypertension (IAH) in children is firstly managed with a conservative therapy, while in the presence of ACS (low abdominal perfusion pressure associated to a new onset of organ dysfunction) early abdominal decompression remains a mandatory approach in order to reduce the high mortality rate associated with this condition [2, 3]. Unfortunately, the ‘‘numbers’’ used in the adult population to perform an abdominal decompression are not applicable in children since the variable abdomen compliance especially in neonates and infants [2]. Many authors [1, 2, 4] suggested proper cut-off values for IAH, to establish the ‘‘critical pressure number’’ at which regularly a switch from IAH to ACS in pediatric patients can be observed. In his work, Dr. Steinau et al. used the criteria proposed by Dr. Eijke [4] to define the pediatric ACS [3]. He considered the pediatric ACS as a lasting IAH higher than 12 mmHg combined with at least one organ dysfunction. We believe that a fixed ‘‘critical’’ number is not suitable for all pediatric patients and that the values proposed by Dr. Stainau are just indicative of an evolving process that could lead or not to a multiple organ dysfunction. Both in adults and children, clinical examination and laboratory testing (base deficit, lactate, unpaired dieresis) are sensitive in detecting abnormalities of tissue perfusion during ACS only after sustained periods of inadequate perfusion, furthermore the early changes in organ metabolism are not easily identified with the traditional monitoring systems. We believe that the outcome of ACS would improve if an earlier detection of regional tissue hypoperfusion would be provided to these patients. Differently from adults, in both neonates and infants, abdominal organs perfusion (kidney) can be monitored using the near infrared spectroscopy (NIRS). This device enables the detection of the states of organ hypoperfusion, allowing a rapid intervention to limit the cascade of multiple organs dysfunction and the development of shock [5–7]. NIRS uses nonpulsatile oximetry to determine venous-weighted oxy-hemoglobin saturation of the underlying regional tissue (rSO2) studied. In pediatrics generally two-site NIRS (brain–kidney) is used for the non invasive assessment of the cardiac output and of its autoregulation in the case of shock [6]. Normally tissue beds with high oxygen consumption (brain) have lower baseline rSO2, where tissue with little metabolic demand (kidney) have a higher baseline rSO2. Figure 1 shows a case of primary ACS for a Clostridium difficilis enterocolitis in a 6-month-old child (7 kg body weight) in which two-site NIRS (brain–kidney) was continuously used to manage the relation between cardiac output and IAP. This patient presented a pathologic change in brain and kidney saturation (dotted arrow) when IAP was *10 mmHg and diuresis was still 1.5 ml/kg/h. This state was not controlled with the medical therapy (deep sedation, neuromuscular M. Di Nardo (&) C. Cecchetti F. Stoppa N. Pirozzi S. Picardo Pediatric Intensive Care Unit, Children’s Hospital Bambino Gesu, Rome, Italy e-mail: matteo.dinardo@tin.it