Cryorecanalization of an obstructed bronchial stent in a 12-year-old boy.

We report a 12-year-old boy who underwent stent implantation into the left main bronchus at the age of 9.5 years for palliation of severe bronchial stenosis. He had developed complete obstruction of the stent by granulation tissue resulting in respiratory deterioration and the requirement of mechanical ventilation. The stent obstruction was treated at the age of 11.5 years by cryorecanalization. In this technique, cooling of the tip of the cryoprobe is used to induce adherence of the obstructing tissue allowing the subsequent removal of tissue particles by retraction of the probe. Under general anesthesia, a miniaturized cryoprobe was advanced via the working channel of a flexible bronchoscope. Repeat maneuvers of freezing and retraction resulted in complete recanalization of the stent. Repeat bronchoscopies 4 and 12 weeks later revealed recurrent formation of some granulation tissue which was removed by repeat cryorecanalization. Seven months after the initial procedure there was a complete patency of the stent. According to our experience, cryorecanalization is a safe and effective alternative for the treatment of stent obstruction by granulation tissue. Due to the introduction of a miniaturized probe, this method is well applicable in children since it can be performed via the working channel of a flexible pediatric bronchoscope.

Comparison of imaging techniques in the diagnosis of bridging bronchus.

Bridging bronchus (BB) is a rare, congenital bronchial anomaly that is frequently associated with congenital cardiac malformations, especially left pulmonary artery sling. It represents an anomalous bronchus to the right originating from the left main bronchus. Discrimination from other bronchial anomalies is important, since BB is frequently associated with bronchial stenoses due to abnormal cartilage rings. This case study describes the findings of bronchoscopy, bronchography and multidetector computed tomography (MDCT) in three patients. Bronchoscopy was helpful in the description of the severity and length of bronchial stenoses. However, it was not possible to establish a diagnosis of BB based on this method in two patients, since it is difficult or even impossible to differentiate the bifurcation from the pseudocarina. It was not possible to establish the correct diagnosis in all patients based on bronchography or MDCT. MDCT was able to depict the relationship of bronchial and vascular structures, which is particularly important in patients with pulmonary artery sling. Multidetector computed tomography is preferable to bronchography as it is less invasive and due to its short acquisition time it can be performed in children with severe respiratory disease. In the current authors' experience, detection of cartilage rings still requires flexible bronchoscopy.

[Thoracoscopic anatomical lung resection in children]. / Die thorakoskopische anatomiegerechte Lungenresektion im Kindesalter.

There are only few pediatric surgical centers across the world with expertise for minimally invasive anatomical lung resections in children. Between September 2003 and September 2005, 67 children underwent thoracoscopic surgery at the Department of Pediatric Surgery, University Hospital of Tuebingen, Germany. In 19 of these cases a lung resection was carried out, 8 of them had an anatomical lung resection. All patients underwent general anesthesia without selective intubation for the procedure. Intrathoracic pressure with insufflation of carbon dioxide of 1.5 l / min was held at 3-5 mmHg. Two 5 mm ports for video and instruments and one 12 mm port for a stapling device were used. Resected lung specimens were removed from the thorax through an additional 2-3 cm long incision. A bronchoscopy was carried out during surgery in all patients. Median age at operation was 5.6 years (range 3 months-20 years). Median operation time was 150 minutes (range 94-250 min). Conversion to open surgery was performed in 3 cases. This was due to bleeding in one child, due to a stiff lung in another patient with cystic fibrosis and due to a vascular and bronchial malformation in a third child suffering from middle lobe syndrome. There were no postoperative complications. Our preliminary results show, that thoracoscopic lung resections in children can be performed without major complications and excellent cosmetic results. For the necessity of a conversion to open surgery possible reasons may be insufficient intrathoracic overview as well as congenital anomalies of the vascular and / or the bronchial tract. Co-morbidities such as rib-fusion, deformities of the thorax or scoliosis can be avoided using thoracoscopic procedures.

Ventricular septal defect closure in a neonate with combined methylmalonic aciduria/homocystinuria.

Methylmalonic acidemia with associated homocystinuria is a rare inborn error of amino acid metabolism affecting energy supply on the cellular level. Its effects on recovery from surgically induced organ ischemia are largely unknown. We report the successful closure of a nonrestrictive ventricular septal defect by following a normothermic strategy combined with ample metabolic substrate supply.

Technical considerations for inhaled nitric oxide therapy: time response to nitric oxide dosing changes and formation of nitrogen dioxide.

UNLABELLED: The aim of the present study was to analyse the time response to nitric oxide (NO) dosing changes as well as the formation of nitrogen dioxide (NO2) with different ventilation systems, respirator settings and application sites during NO inhalation. The inspired NO and NO2 concentrations were continuously measured using chemiluminiscence within a dummy ventilatory system equipped with two different respirator systems (Siemens Servo 900c and Bear BP 2001). NO was either introduced into the afferent limb of the ventilatory circuit close to the endotracheal tube (site A) or into the so-called low pressure port of the Servo 900c respirator, far away from the endotracheal tube (site B). In addition, the decay of the inspired NO concentration after cessation of the NO gas flow was studied. This decay was considerably prolonged when NO was introduced at site B (time constants: tau = 7.19 min versus tau = 0.29 min). Within the concentration range studied (0-25 ppm NO) a linear correlation between the NO and NO2 concentration was found. At site A and an inspired oxygen concentration of > 0.95 NO2 formation amounts to 1.14% +/- 0.11% of the NO concentration. Using this value one can calculate the NO2 formation for a given NO dose. For example, when 40 ppm NO are applied, a concentration of 0.45 ppm NO2 can be expected, which is well below the relevant toxic concentrations. However, when NO was introduced at site B, NO2 formation was significantly increased to 1.61% +/- 0.16%. Passage of the ventilated gas through soda lime led only to a slight and insignificant reduction in NO2 concentration. The continuous flow respirator BP 2001 showed a significantly lower NO2 concentration when compared to the non-continuous flow respirator Servo 900c (0.64 +/- 0.11% vs.1.14 +/- 0.11%). CONCLUSION: The application of NO close to the endotracheal tube is associated with a much faster response of the actual inspired NO concentration to dosing changes and shows the lowest NO2 formation. In order to avoid toxic NO2 concentrations, an upper limit of 40 ppm NO is recommended for continuous NO inhalation.

Increased turnover of serotonin in children with pulmonary hypertension secondary to congenital heart disease.

Serotonin (5HT) is a potent vasoconstrictor of the pulmonary vascular bed and may be involved in the pathophysiology of secondary pulmonary hypertension in children with a left-to-right shunt due to a congenital heart defect. To test this hypothesis we measured the total and free 5HT concentration in blood as well as the urinary excretion of its main metabolite 5-hydroxyindoleacetic acid (HIAA) in children showing a left-to-right shunt with (n = 10) and without (n = 18) pulmonary hypertension. 5HT and HIAA were also measured in children after corrective cardiac surgery using cardiopulmonary bypass (n = 14) and in controls without congenital heart disease (n = 18). The concentrations of total and free 5HT were not significantly different between controls and patients with a left-to-right shunt. After cardiac surgery total 5HT concentration was significantly reduced by about 65% owing to a postoperatively reduced platelet count. In patients with a left-to-right shunt the total 5HT content was similar in the right atrium (204.0 +/- 17.3 ng/ml), pulmonary artery (189.0 +/- 19.1 ng/ml), and aorta (195.0 +/- 19.3 ng/ml), as was the free 5HT concentration. Therefore no net release of 5HT from platelets occurred between these sampling sites. In patients with pulmonary hypertension, the urinary excretion of HIAA was significantly increased when compared with controls and patients without pulmonary hypertension. It is concluded that turbulent blood flow in children with a left-to-right shunt does not lead to a significant release of 5HT from platelets. However, the increased urinary excretion of HIAA in patients with pulmonary hypertension indicates an increased turnover of 5HT, probably due to an increased number of intrapulmonary neuroepithelial cells or a higher metabolic rate of 5HT within those cells.

[Improvement of perioperative hemodynamics and gas exchange by inhalation of nitric oxide in children with congenital cardiopulmonary defects]. / Verbesserung der perioperativen Hämodynamik und des Gasaustausches durch Inhalation mit Stickstoffmonoxid bei Kindern mit angeborenen kardiopulmonalen Fehlbildungen.

OBJECTIVES: In critically ill infants and children before or after surgery for congenital cardiopulmonary disease it was evaluated whether continuous NO inhalation can reduce pulmonary artery pressure (PAP) and improve arterial oxygen saturation (SaO2). METHODS: All patients (n = 24; age 1 day-6.5 years) were intubated and artificially ventilated. They had either secondary pulmonary hypertension (n = 16), acute respiratory distress syndrome (n = 3), or reduced SaO2 (n = 5) due to pulmonary hypoperfusion. NO was introduced into the afferent limb of the ventilator circuit close to the endotracheal tube, while continuously measuring the inspired NO and O2 concentrations. The initially applied concentration of NO was 20 +/- 2.0 ppm. RESULTS: The hemodynamic condition and/or oxygen saturation was significantly improved by NO in 23 patients (95%). Mean PAP declined significantly from 45 +/- 7 to 28 +/- 3.7 mm Hg, while mean systemic arterial pressure remained constant (56 +/- 2.1 vs. 58 +/- 2.5 mm Hg). This was related to a selective reduction in pulmonary vascular resistance by 48 +/- 8.5%. SaO2 increased significantly (p < 0.05) from 83 +/- 2.5% to 93 +/- 1.5% due to a decreased intrapulmonary right-to-left shunt. NO therapy was applied with a median of 6 days (range 1.5-36 days). During NO inhalation methemoglobin concentration was significantly increased (0.77 +/- 0.05% vs. 1.46 +/- 0.15%), but neither was oxygen transport capacity affected, nor was any evidence for accumulation observed. Using a model ventilatory circuit, a nitric dioxide (NO2) formation of 1.14 +/- 0.11% of the applied NO concentration was measured, i.e. approximately 0.5 ppm NO2 at 40 ppm NO. This amount of NO2 in the inspired gas is well below toxicologically relevant concentrations. CONCLUSIONS: Low-dose NO inhalation selectively reduces PAP and improves SaO2 in children with congenital cardiopulmonary disease during perioperative intensive care. It is expected that the overall hemodynamic improvement is related to a reduced afterload of the subpulmonary ventricle without changes in coronary perfusion pressure, as is often observed with other vasodilators applied intravenously. We recommend an upper dose limit of 40 ppm NO for continuous NO inhalation to avoid possible toxicologically relevant NO2 concentrations.

A six-year experience with paravaginal defect repair for stress urinary incontinence.

One hundred forty-nine consecutive patients who had surgery from May 1890 through December 1986 were evaluated to assess the functional and anatomic results of the paravaginal defect repair for stress urinary incontinence. All patients had their preoperative assessment, operative procedure, and postoperative follow-up managed by the authors. Twelve percent of the patients had one or more previous surgical procedures for urinary incontinence. Sixteen percent of the patients had the preoperative diagnosis of urinary incontinence with mixed components of true stress incontinence and detrusor instability. Postoperatively, 6% of all patients developed evidence of cuff prolapse; 5% had an enterocele. In none of those patients did the defect prolapse to the hymen. Five percent of the patients had postoperative evidence of a persistent cystocele, all of which were smaller than they had been preoperatively. An assessment of the anatomic results of the repair demonstrates that meticulous attention must be paid to the proper repair of the paravesical defect, to support of the vaginal cuff, and to management of the cul-de-sac of Douglas to minimize postoperative anatomic defects. Ninety-seven percent of patients had excellent functional results with no postoperative complaints of stress urinary incontinence.