High doses of benzodiazepine predict analgesic and sedative drug withdrawal syndrome in paediatric intensive care patients.

AIM: Critically ill children can develop withdrawal syndrome after prolonged analgesia and sedation in a paediatric intensive care unit (PICU), when treatment is stopped abruptly or reduced quickly. The aim of this study was to evaluate the incidence of withdrawal syndrome in patients after three or more days of analgesic or sedative drug therapy, using a validated scale. We also analysed the association between withdrawal syndrome and the patients' outcome and factors related to analgesia and sedation treatment. METHODS: This prospective observational study analysed 89 periods of weaning from analgesia and sedation in 60 children between October 2010 and October 2011. Of these, 65% were less than six months old and 45% were admitted to the PICU after heart surgery. Withdrawal syndrome was assessed using the Withdrawal Assessment Tool-1 (WAT-1) scale. RESULTS: The incidence of withdrawal syndrome was 37%, and the only variable that predicted its presence was the highest administered dose of benzodiazepine. The duration of weaning, Sophia Observational Withdrawal Symptom scale score and nurse judgment were also associated with positive WAT-1 scores. CONCLUSION: Withdrawal syndrome should be considered after three or more days of analgesic or sedative treatment. A high dose of benzodiazepine increases the risk of developing withdrawal symptoms.

Corticosteroids and surfactant change lung function and protein leaks in the lungs of ventilated premature rabbits.

Fetal rabbits were treated with corticosteroids by maternal administration for 48 h before delivery at 27 d gestational age. The treated and control rabbits were placed on ventilator-plethysmographs so that ventilation could be adjusted by regulation of tidal volumes to 10-13 ml/kg body wt. [125I]albumin was mixed with fetal lung fluid at birth, alternate rabbits from each litter were treated with Surfactant-TA, and [131I]albumin was injected intravascularly. The movement of the labeled albumins into and out of the alveolar wash and lung tissue was measured after 30 min of ventilation. Corticosteroid treatment (total dose, 0.2 mg/kg betamethasone) significantly decreased the protein leak across the endothelium (P less than 0.001) but increased the protein leak across the epithelium (P less than 0.001). Surfactant treatment decreased both the endothelial and epithelial leaks, and the combination of surfactant and corticosteroid treatments decreased endothelial leaks to 29% of control values and increased compliance more than either treatment alone. The 48-h corticosteroid treatment did not increase alveolar surfactant pool sizes. Corticosteroids significantly changed lung protein leaks independently of surfactant, and improved the response of the preterm lung to surfactant treatments.

Lysophosphatidylcholine uptake and metabolism in the adult rabbit lung.

Tracer quantities of 3H-labeled lysoPC and 32P-labeled natural rabbit surfactant were given intratracheally via a bronchoscope and [14C]palmitate was given intravenously to 25 rabbits with labeled PC and lysoPC measured in the alveolar wash, lung homogenate, lamellar bodies and microsomes at five times from 10 min to 6 h after tracheal injection. Surprisingly, only 31% of the administered lysoPC remained in its original form in the total lungs (alveolar wash + lung homogenate) by 10 min, of which 77% was in the alveolar wash. Meanwhile, by 10 min an additional 37% was already converted to PC, of which more than 98% was in the lung homogenate. LysoPC continued to be rapidly and efficiently converted to PC, with 62% conversion measured at 3 h. The converted lysoPC initially appeared with high specific activity in microsomes, then in lamellar bodies, and finally in the alveolar wash. The intravascular palmitate labeled lung PC had similar specific activity-time profiles in the subcellular fractions, while intratracheally administered natural rabbit surfactant had a constantly low specific activity in microsomes and much higher specific activities in lamellar bodies and alveolar wash. Another 25 rabbits received intratracheal lysoPC labeled in both the choline and palmitate moieties and then were studied from 1 to 24 h after tracheal injection. The ratio of the palmitate to choline labels indicated uptake and conversion to PC primarily by direct acylation rather than transacylation and by intact reuptake and conversion rather than breakdown and resynthesis. LysoPC is an attractive 'metabolic probe' of surfactant metabolism which undergoes very rapid and efficient intracellular conversion to PC via a subcellular pathway that parallels the remodeling and de novo synthetic pathways.

Polyethylenimine shows properties of interest for cystic fibrosis gene therapy.

Before being considered for a cystic fibrosis (CF) gene therapy trial, any gene delivery agent must be able to show that it produces low levels of toxicity as well as being able to protect the DNA from nuclease degradation. Here we show that complexes of linear polyethylenimine (L-PEI) and DNA can repeatedly be administered to animals (up to 21 consecutive days) without eliciting an immune response against PEI/DNA particles or inducing toxic side effects due to accumulation of PEI in the lungs. However, the host response to the exogenous protein resulted in some decrease of expression. PEI-mediated transfection was unaffected by treatment of the complexes with DNase (frequently used to reduce the viscosity of lung secretions in CF patients). Taken together, these properties make L-PEI a valuable vector for gene therapy of CF.

The life cycle of a low-molecular-weight protein of surfactant (SP-C) in 3-day-old rabbits.

To clarify the metabolic cycle of a low-molecular-weight protein of surfactant (SP-C), we obtained alveolar surfactant from 3 day old rabbits killed 24 h after the tracheal administration of 32P or L-[35S]methionine (donors). Aliquots of this naturally labelled surfactant were administered into trachea to 3-day-old rabbits (recipients) which were killed after 1 min or 3, 8 or 24 h. We then analyzed the radioactivity associated with SP-C and with saturated phosphatidylcholine in fractions of lung lavage fluid and in lung homogenate. We found that alveolar SP-C is turned over faster than saturated phosphatidylcholine, that alveolar macrophages do participate in the removal of SP-C and that SP-C does not enter the fraction of alveolar surfactant that remains unsedimented after ultracentrifugation. Considering the whole lung, SP-C and saturated phosphatidylcholine are turned over at a comparable speed.

Clearance of surfactant phosphatidylcholine from adult rabbit lungs.

Rabbits were given various doses of rabbit surfactant and treatment doses of approximately 100 mg/kg body wt of calf surfactant and Surfactant TA by tracheal injection. The linear loss of radiolabeled phosphatidylcholine from the total lung (alveolar wash and lung tissue) was 3.1, 1.5, and 1.8%/h for rabbit surfactant, calf surfactant, and Surfactant TA, respectively. After 24 h only 6% rabbit, 19% calf, and 9.7% Surfactant TA phosphatidylcholine were recovered by alveolar wash, and alveolar macrophage fractions contained less than 1% of the injected labeled phosphatidylcholine. The loss of rabbit surfactant phosphatidylcholine 24 h after tracheal injection did not change for doses in the range of 0.5-70 mumol phosphatidylcholine per kilogram, indicating nonsaturable clearance pathways. Very little of the labeled rabbit surfactant phosphatidylcholine lost from the lungs could be recovered in other organs, and 90% of the recovered labeled phosphatidylcholine in the liver was unsaturated, implying de novo synthesis using precursors from degraded phosphatidylcholine. The surfactant did not change endogenous lung phosphatidylcholine synthesis or its secretion to the alveolus. There were no adverse effects of the surfactant treatments noted in healthy rabbits.

Corticosteroid potentiation of surfactant dose response in preterm rabbits.

Fetal rabbits were treated with corticosteroids by maternal administration for 48 h before delivery at 27 days gestational age. Both corticosteroid-treated and control animals then received exogenous natural rabbit surfactant at birth at doses of 0-75 mg lipid/kg. After 10 min of ventilation at tidal volumes of 12-15 ml/kg, static pressure-volume measurements were made. At all surfactant doses there was a significantly higher maximal lung volume, higher dynamic compliance, and lower pressure requirement in the corticosteroid-treated than in the control rabbits (P less than 0.01). Control animals showed incremental improvements in dynamic compliances and maximal lung volumes up to a dose of 50 mg/kg, whereas corticosteroid treated animals improved to a maximum at the low dose of 15 mg/kg (P less than 0.01). However, surface tension as assessed by lung stability index improved with increasing surfactant dose but was not significantly different between corticosteroid-treated and control animals at a given dose. The results imply that maternal corticosteroid treatment potentiates surfactant replacement by a change in lung structure that is independent of surface tension effects.

Clearance of surfactant phosphatidylcholine via the upper airways in rabbits.

A possible route of clearance of surfactant phosphatidylcholine from the lungs is via the airways. To quantify surfactant loss via this pathway, latex bags were surgically placed into the abdomens of adult rabbits such that secretions cleared via the esophagus could be collected. The rabbits then were given treatment or trace doses of radiolabeled phosphatidylcholine-surfactant by tracheal injection and/or intravascular radiolabeled precursors of phosphatidylcholine. Labeled saturated phosphatidylcholine was measured in all fluids that were collected from the bags at 2-h intervals for 24 h and in alveolar washes and lung tissues at 24 h. No more than 7% of either treatment or trace doses of intratracheal surfactant-saturated phosphatidylcholine was lost via clearance up the airways over 24 h. Clearances of endogenously synthesized and secreted saturated phosphatidylcholine were estimated to be no more than 3% of the flux of labeled saturated phosphatidylcholine through the alveolar pool. These experiments demonstrate that surfactant phosphatidylcholine clearance via movement up the airways is not a major pathway leading to surfactant catabolism.

Pulmonary effects of acute prenatal asphyxia in ventilated premature lambs.

The effect of profound repetitive prenatal asphyxial insults on the cardiopulmonary function of premature ventilated lambs was studied. Twenty-nine fetal lambs (approximately 138 days gestational age) were exteriorized. In 16 of these lambs, the umbilical cord was occluded for 4 min then released for 10 min. This asphyxial episode was repeated until the arterial pH was approximately 7.00, and the mean arterial blood pressure was less than 40 mmHg and falling. The 13 control lambs were simply exteriorized with the umbilical circulation intact. The lambs were then ventilated for 3-4 h. There were no differences between the control vs. asphyxiated lambs in pulmonary compliances (0.57 and 0.58 ml.cmH2O-1.kg-1) wet-to-dry weight ratios (8.18 and 7.55), cardiac outputs (177.8 and 141.8 ml.kg-1.min-1), surfactant-saturated phosphatidylcholine pool sizes, or atrial and/or ductal shunts. Asphyxia did not interfere with the redirection of blood away from atelectatic lung segments created by bronchial obstruction with balloon catheters. Also, although the bidirectional flux of protein into and out of the airways of these preterm lambs was large relative to term lambs, there was no effect of asphyxia on this protein leak. In this animal model, prenatal asphyxia did not impact negatively on the severity of the respiratory failure.

Turnover of phospholipids isolated from fractions of lung lavage fluid.

To clarify the steps following surfactant secretion, we injected adult rabbits with radioactive palmitate, lavaged the airways, removed the cells, separated by ultracentrifugation lavage components into two fractions (B and C), and followed the labeling of phospholipids of these fractions. The results were compatible with the view that total and saturated phosphatidylcholine are transferred from B to C. Furthermore, the fluxes of total and saturated phosphatidylcholine through fraction C (0.45 and 0.30 mumol . h-1 . g lung-1, respectively) were compatible with the actual estimates of surfactant recycling. The labeling of phosphatidylglycerol ruled out a simple precursor-product relationship between B and C but was compatible with a nonideal first-order relationship. The labeling of phosphatidylinositol, cardiolipin, and phosphatidylethanolamine was incompatible with the existence of a direct precursor-product relationship between B and C. The labeling of total and saturated phosphatidylcholine suggests that fraction B may be made by active surfactant, whereas fraction C may contain surfactant modified for reuptake or for reuptake and catabolism.

Rapid improvement of static compliance after surfactant treatment in preterm infants with respiratory distress syndrome.

Respiratory mechanics were measured in 20 preterm infants before and in the 24-hr period after treatment with surfactant. All infants were enrolled in the rescue clinical trial with Curosurf carried out in the Neonatal Intensive Care Unit. They received a dose of 200 mg/kg lipid surfactant intratracheally after birth. Static compliance of the respiratory system (Crs) was measured by the single breath occlusion technique during both spontaneous and mechanical ventilation. Resistance of the respiratory system (Rrs) and expiratory time constant (Trs) were also measured. As early as 3 hr after surfactant administration a significant improvement of 45% in Crs measured during mechanical ventilation (CrsV) was noted (0.40 +/- 0.14 vs 0.58 +/- 0.17 mL/cm H2O/kg, P < 0.001), together with a significant improvement of the arterial/alveolar O2 tension ratio (Pa/AO2) (0.12 +/- 0.03 vs 0.30 +/- 0.16, P < 0.01). The improvement of CrsV and Pa/AO2 was confirmed 24 hr later (0.55 +/- 0.15 mL/cm H2O/kg and 0.33 +/- 0.18, respectively). A significant correlation was found between Crs and Pa/AO2 ratio (r = 0.56, P < 0.001). Time constant values were significantly higher after surfactant treatment (0.15 +/- 0.07 vs 0.09 +/- 0.03 sec; P < 0.01). Rrs remained unchanged. These data indicate that Curosurf given intratracheally after birth determines a rapid improvement of respiratory mechanics as soon as 3 hr after dosing, together with the improvement of oxygenation. From the findings obtained with the present study we show evidence that respiratory system mechanics may be a useful physiological measure to guide ventilatory strategy following surfactant therapy.

The effect of a 'containing' position in a hammock versus the supine position on the cutaneous oxygen level in premature and term babies.

We evaluated the influence of positioning, and particularly a containing position in a hammock compared with the supine position, on the respiration of the newborn. Recordings of the transcutaneous oxygen level of 40 preterm babies and 10 full-term babies placed in their incubators alternately in the two positions have been analyzed. We found no significant differences between the means of the oxymetric indexes in the hammock and in the supine position, even when the babies had different gestational ages and birth weights. The advantages of the containing position for the neuromotor and relational development of the newborn in the first year of life in comparison with the effects of supine placement, which should be avoided as much as possible in the premature, are pointed out.

Primary occlusion of the iliac and femoral artery in two newborn infants: efficacy of medical treatment.

Arterial occlusion not associated with umbilical artery catheterization is a rare condition in the newborn period. Two neonates with femoral and iliac artery occlusion in the first days of life are presented. While almost all the cases described in the literature underwent surgical treatment, these two infants received only pharmacological treatment with good results. Although angiography remains the examination of choice for the diagnosis, noninvasive angiologic evaluations such as oscillometry and Doppler flow examination have been used for both diagnosis and follow-up. The etiology in these two cases remains unknown. The results obtained with these two neonates suggest that with prompt recognition of this disorder and an aggressive medical treatment, a complete recovery could be achieved.

[Nitric oxide via inhalation in the newborn infant and the child with acute hypoxemic respiratory failure]. / Ossido nitrico per via inalatoria nel neonato e nel bambino con insufficienza respiratoria ipossiemica acuta.

Inhaled nitric oxide (NO) has been recently proposed as a new treatment in newborns and children with severe hypoxemic respiratory failure. Differently from other vasodilators, inhaled nitric oxide selectively lowers pulmonary vascular resistance and pulmonary arterial pressure, and improves the ventilation/perfusion matching by directing pulmonary blood flow toward better ventilated areas, ultimately improving systemic oxygenation. In our experience, we have observed that inhaled NO may acutely ameliorate gas exchange in patients with severe respiratory failure. This may allow a reduction of both ventilatory parameters and fraction of inspired oxygen, thus limiting further damage to the lungs. Nonetheless, the underlying disease and the clinical conditions before NO treatment seem to maintain a crucial role in the ultimate prognosis of these patients. Further studies are needed in order to better define indications, dosages, and safety of nitric oxide treatment, and to verify its authentic prognostic value in neonates and children with acute respiratory failure.

[Congenital diaphragmatic hernia: the use of ECMO and other modern therapeutic strategies]. / Ernia congenita diaframmatica: impiego dell'ECMO e di altre moderne strategie terapeutiche.

Congenital diaphragmatic hernia (CDH) with severe respiratory failure is still associated with significant mortality. Modern treatment of CDH is now widely accepted to be delayed repair after stabilization. Availability of Extracorporeal Membrane Oxygenation (ECMO) led up to real improvement in survival. Several others modalities have been recently used in attempting to reduce the need for ECMO or, otherwise, to improve outcome. Multicenter controlled trial of high-frequency oscillatory ventilation (HFOV), exogenous surfactant replacement, nitric oxide (NO) inhalation and, more recently, liquid ventilation have been reported. We describe four cases of CDH treated in our ECMO-centre from 1993 to date, 25% surviving. One patient died by pulmonary hypertension and multiorgan failure while on ECMO; one by pulmonary hypertension and cardiac failure and one by sepsis, both ones far from effective ECMO weaning. All patients underwent extracorporeal bypass because of Oxygenation Index (OI) ranging 65-215. Venovenous has been always made but one patient needed early switching on venoarterial. Several trials with surfactant and nitric oxide were performed during extracorporeal bypass. In survived patient, diaphragmatic defect was repaired out of ECMO. Patients survived to the weaning underwent vascular reconstruction. Our ECMO data confirm worse prognosis for CDH rather than other ECMO requiring diseases (we report 66.7% surviving in overall ECMO application); we underline real improvement by using alternative therapies together with extracorporeal bypass and primary role of OI as predicting index for ECMO.

[The evolution of care for the critical child: pediatric intensive care]. / L'evoluzione dell'assistenza al bambino critico: la terapia intensiva pediatrica.

Pediatric intensive care units (PICUs) have been developed to provide intensive care for children between post-neonatal age and adolescence. These units have largely been developed in North America, mainly in tertiary hospitals. In Italy, critically ill children are still often nursed on adult ICU's, where medical and nursing staff often lack pediatric training. Here we report the first 5-year experience of the multidisciplinary PICU developed at the Department of Pediatrics, University of Padua, focusing on PICU and patients characteristics, as well as on the evaluation of outcome by means of the Pediatric Risk of Mortality (PRISM) score.

[Extracorporeal membrane oxygenation (ECMO) in the newborn infant and the child with intractable respiratory failure]. / Ossigenazione extracorporea a membrana (ECMO) nel neonato e nel bambino con insufficienza respiratoria intrattabile.

Extracorporeal membrane oxygenation (ECMO) has become a nearly standard treatment for neonates with refractory hypoxemic respiratory failure due to various disease. Even though in the non-neonatal age the experience is less extensive, an increased widespread interest on the possible applications in children with severe life-threatening respiratory or cardiovascular insufficiency is well documented in the literature. General contraindications include presence of active bleeding, underlying lethal disease, congenital malformations, or severe brain damage. Whilst in the neonatal population common entry criteria have been widely accepted, the identification of precise parameters capable to predict mortality and thus indicating an ECMO support in older patients are still lacking. At present, nonetheless, more than 10.000 newborns and 1.000 children with severe respiratory insufficiency at high mortality risk have received an ECMO treatment, with a survival rate of more than 80% and 50%, respectively. The initial results of our ECMO program for both neonatal and pediatric patients with refractory respiratory failure are encouraging, both in terms of mortality and morbidity, and they will be briefly discussed.

[Transportation of the critical newborn infant and child]. / II trasporto del neonato e del bambino critico.

Advance in the science and technology of neonatal and pediatric critical care have resulted in improved outcome for high risk newborn and children. Effective interhospital transport programmes are necessary for the appropriate use of resources and has become an integral component of regionalized perinatal care. It is now well established that use of an organized neonatal and pediatric transport team results in a fall in mortality and morbidity of infant. The American College of Obstetrician and Gynecologist and, recently, American Academy of Pediatrics published guidelines and recommendations for safe interhospital transfer of neonates, infants and children. Training of personnel, selection of equipment, organization and communication between hospitals are critical elements of a successful transport system. We present an overview of the role, principles and operating procedures of such neonatal-pediatric transport team and the basis of clinical stabilization before and during transfer. We also discuss data of the first 17 month experience of the Neonatal-Pediatric Transport Service of the Department of Pediatrics, University of Padua.

Practice of analgesia and sedation in Italian Paediatric Intensive Care Units: did we progress?

BACKGROUND: No strong recommendation was reported in management analgesia and sedation of critically ill children. The present study was performed to describe the current practice of analgesia and sedation in Pediatric Italian Intensive Care Units, in order to evaluate the adherence to last published pediatric guidelines. METHODS: A questionnaire was sent to 24 Italian Paediatric Intensive Care Units during 2010. RESULTS: One Hundred percent of contacted centers returned the filled form. All Pediatric Italian Intensive Care Units used the same combination (opioid plus benzodiazepine); 50% of centers referred to regularly monitor the level of sedation, but only 37% of them used validate tools. Withdrawal syndrome was regularly monitored in 25% of contacted Pediatric Italian Intensive Care Units; Finnegan scale was the only adopted scale. CONCLUSION: National pediatric intensivists identified the same drug strategy to obtain analgesia and sedation in their patients, according to last published guidelines. Assessment of analgesia and sedation was more diffuse but not regularly performed and different methods were used. Withdrawal syndrome was monitored in a minority of contacted centres. Considering our data the practice of analgesia and sedation in Italian Pediatric Intensive Care Units is improved but not yet completely adherent to last international recommendations.

Assessing sedation in a pediatric intensive care unit using Comfort Behavioural Scale and Bispectral Index: these tools are different.

BACKGROUND: The aim of this paper was to monitor comfort in pediatric critical ill patients which is necessary to adequate analgesic and sedative therapy. The primary objective of this prospective observational study was to measure the level of sedation in a Pediatric Intensive Care Unit (PICU) of a tertiary care Hospital, using Comfort Behavioural Scale (CBS) and Bispectral Index (BIS), evaluating the agreement between these tools; secondly we analyzed the correlation of an adequate level of sedation and patient's outcome. METHODS: We enrolled 46 patients, mechanically ventilated for almost 12 hours, monitored at a basal level and during a stimulus (tracheal suctioning). As outcome variables we analyzed: length of ventilation and PICU stay, duration of sedative therapy and weaning, time between beginning of sedative administration and start of weaning, presence of infection. RESULTS: Twenty-six percent (doctor CBS score), 34.8% (nurse CBS score) and 73.9% (BIS) of our population were found adequately sedated; none state of undersedation was reported. During the stimulus the percentage of adequately sedated patients according to CBS became 78.2%. CBS level of agreement versus BIS was weak. No significative difference was found between doctor and nurse CBS score. Length of PICU stay and duration of sedative administered were significant shorter in patients adequately sedated at Bispectral Index monitoring; no outcome variable resulted significant looking at CBS score. CONCLUSION: Our data support the risk of oversedation in critically ill patients and the difference between CBS and BIS, especially in evaluating light oversedation state. The presence of an excessive level of sedation evaluated by BIS was associated with duration of hospitalization and sedative administration.