Comparison of four methods of lung volume recruitment during high frequency oscillatory ventilation.

PURPOSE: To compare four methods of volume recruitment upon initiation of high frequency oscillatory ventilation (HFOV). METHODS: Anesthetized intubated neonatal piglets (n = 10) underwent repeated saline lavage, followed by conventional mechanical ventilation (CMV). After transition to HFOV at a mean airway pressure 8 cmH2O above CMV (P(basal)), four methods of lung volume recruitment were tested in each animal in random order: Escalating--step-wise pressure increments over 6 min to a peak mean airway pressure 12 cmH2O above P(basal); Sustained dynamic inflation (DI)--a 20 s inflation to the same peak pressure; DI repeated six times for 1 s; Standard--mean airway pressure set directly at P(basal). After each recruitment method, HFOV continued at P(basal) for 15 min. Thoracic gas volume and distribution of aeration were determined by single slice computed tomography, and oxygenation by arterial blood gas sampling. RESULTS: Escalating recruitment resulted in the greatest thoracic gas volume 15 min post recruitment [77 +/- 3.3% of total lung capacity vs. 70 +/- 4.2% (Sustained DI), 65 +/- 3.5% (Repeated DI),63 +/- 5.1% (Standard); mean +/- SEM; P = 0.042, ANOVA]. All methods resulted in a reduction in non-aerated lung, with the greatest redistribution to normally aerated lung being with Escalating recruitment. Oxygenation 15 min post recruitment was better with the Escalating method than with Repeated DI or Standard recruitment (pO2 307 +/- 41 vs. 159 +/- 36 vs. 134 +/- 39 mmHg, respectively; P = 0.016, ANOVA). CONCLUSIONS: Escalating recruitment produced the greatest increase in lung volume and resolution of atelectasis, and is recommended for lung volume recruitment upon initiation of HFOV.

Polyflex stenting of tracheomalacia after surgery for congenital tracheal stenosis.

Polyflex self-expanding stents (Rüsch, Germany) were used in three young children who had presented with life-threatening long-segment tracheal stenosis with bronchial stenosis in two cases. Two children had slide tracheoplasties and subsequently aortic homografts and another tracheal resection and autotracheoplasty. However, in all cases persistent lower tracheal malacia necessitated stenting. Complications of granuloma, stent migration or dislodgement occurred in all cases. A fatal tracheo-aortic fistula occurred in one child. Granuloma in one was treated successfully with steroids. One child survives.

MRI and preoperative embolization of a nasal cavity haemangioma in a child.

Haemangiomas are common benign tumours of the head and neck region in children. The nasal cavity, however, is an extremely rare site for such lesions in childhood. We present the typical MRI features of a nasal cavity haemangioma in a 12-year-old girl. Biopsy was avoided because of the MRI diagnosis and preoperative embolization of the mass was performed.

Balloon dilatation in children for oesophageal strictures other than those due to primary repair of oesophageal atresia, interposition or restrictive fundoplication.

BACKGROUND: Balloon dilatation of the oesophagus in children has been performed predominantly for treating strictures, which are the result of primary repair of oesophageal atresia, interposition surgery or restrictive Nissen's fundoplication. Reports of the use of this technique for alternative causes of stricture are few. OBJECTIVE: To report our experience and success with balloon dilatation of strictures due to caustic ingestion, achalasia, oesophagitis, congenital stenosis, and epidermolysis bullosa (EB) and to make comparisons with our treatment of patients with primary repair of oesophageal atresia (OA), as well as with reports in the English language literature. MATERIALS AND METHODS: Retrospective review of fluoroscopically guided balloon oesophageal dilatation procedures in 19 patients over a 5-year period, and comparison of those performed for OA repair complications with those due to other diseases. The average radiation dose, per procedure, was calculated by a medical physicist. RESULTS: Ten patients had strictures as a result of primary repair of OA. Three patients had stricture as a result of EB, two from achalasia, two from caustic injury, one due to an oesophageal web and one from reflux oesophagitis. Our results show that the technique can also be curative for the last group and that it may be used intermittently to alleviate symptoms in ongoing diseases. We have not experienced any complications and have also calculated that, even with prolonged use of multiple procedures, the radiation exposure is comparable to other radiological techniques. CONCLUSIONS: Patients with alternative causes for oesophageal stricture may be treated to resolution within 2 years using balloon dilatation. Ongoing diseases such as EB require ongoing dilatation, but balloon dilatation of strictures has been successful in alleviating swallowing difficulty. Patients with stricture from OA repair sometimes need ongoing dilatation. Radiation exposure for multiple procedures, over an extended period, is comparable to that from a single abdominal CT, and can be considered acceptable when repeat complex surgery is the alternative treatment option, or when ongoing incurable disease is the cause of the stricture.

Comparison of MR angiography and conventional angiography in the investigation of intracranial arteriovenous malformations and aneurysms in children.

BACKGROUND: Magnetic resonance angiography (MRA) is an attractive alternative to conventional catheter angiography (CCA) in children, especially for the detection of intracranial arteriovenous malformations (AVMs) or aneurysms in the out-of-hours setting, because it has fewer risks and complications. OBJECTIVE. To compare MRA with CCA for the detection of intracranial AVMs, aneurysms and arterial anatomy in children. MATERIALS AND METHODS: Retrospective blinded review of MRAs and CCAs by two independent paediatric radiologists, in a group of 19 children already diagnosed with AVMs, aneurysms and subarachnoid haemorrhage (SAH) and who had undergone both imaging techniques. RESULTS: Abnormalities were identified on MRA in 15 of 19 patients and by CCA in 11 of 19 patients. MRA showed one aneurysm, nine AVMs, three haemorrhages and two indeterminate lesions. CCA showed nine AVMs and two indeterminate lesions. The two modalities showed excellent correlation in the detection of AVMs in nine patients. Vascular supply to the AVMs correlated well in four cases. There was complete disagreement in the determination of vessel supply in one case, and in two cases CCA showed additional vessel supply compared to MRA, while in two further cases MRA showed an additional vessel supply compared to CCA. CCA was superior to MRA in demonstrating arterial anatomy, except with regard to the anterior and posterior communicating arteries where MRA was superior. CONCLUSIONS: The high sensitivity of MRA in the detection of AVMs when compared to CCA and the low incidence of aneurysms support the use of MRA as the initial imaging modality when intracranial haemorrhage is diagnosed on CT, especially in the out-of-hours setting.

Incidental magnetic resonance image sinus abnormalities in asymptomatic Australian children.

Plain X-rays, computed tomography (CT) and magnetic resonance imaging (MRI) scans performed for non-ENT reasons often reveal incidental sinus mucosal changes. These changes need to be correlated clinically before diagnosing rhinosinusitis. This study examined the prevalence of such changes in MRI scans in children up to age 16. Scans were scored using an adapted Lund-Mackay classification and were positive when one or more sinuses showed abnormalities. Randomly selected scans in the retrospective arm revealed a prevalence of 20 of 62 (32.3 per cent). In the prospective arm 45 of 60 children were defined as truly asymptomatic, of which 14 scans (31 per cent) were positive. Other studies in adults and children using CT and MRI report a prevalence range of roughly 30 to 45 per cent. This variability may be attributed to differences of study design, definitions of population age, definitions of asymptomatic and definition of abnormal sinus. Other plausible factors to explain regional differences are climate and frequency of upper respiratory tract infections.