Treatment of subclavian-axillary vein thrombosis: long-term outcome of anticoagulation versus systemic thrombolysis

Objective: To investigate long-term clinical and morphological outcome of patients with subclavian–axillary vein thrombosis treated with systemic thrombolysis compared to anticoagulation in a retrospective, nonrandomised study. Methods: We studied 95 consecutive inpatients with subclavian–axillary vein thrombosis treated either with systemic urokinase thrombolysis and subsequent oral anticoagulation (n=33) or with anticoagulation only (n=62). Anticoagulation was performed with heparin and phenprocoumon. Patients were followed for median 40 months (IQR 14 to 94) for symptomatic upper extremity post-thrombotic syndrome and for venous recanalisation by duplex ultrasound. Results: Primary technical success rate of the systemic thrombolysis was 88% (n=29) with seven peri-intervention bleeding complications (21%). No complication was observed in patients with anticoagulation only (p<0.0001). At the time of follow-up, duplex sonography showed a thrombotic subclavian vein in 40 of 83 patients (48%), but only 9 of 95 patients (10%) had a symptomatic upper extremity post-thrombotic syndrome. Patients with systemic thrombolysis exhibited a 60% adjusted reduced risk for a thrombotic subclavian vein at the time of follow-up compared to patients with anticoagulation only (95% CI: 0.2 to 0.9, p=0.03). However, the frequency of symptomatic post-thrombotic syndrome after thrombolysis and anticoagulation was similar (adjusted p=0.6). Conclusion: Systemic thrombolysis of subclavian–axillary vein thrombosis has an acceptable primary technical success rate and improves venous recanalisation rates compared to anticoagulation. However, the high rate of complications during thrombolysis and the lack of clinical benefit suggest that conservative treatment may be favoured.     

Risk factors for respiratory syncytial virus associated apnoea

Respiratory syncytial virus (RSV) infections are characterized by upper or lower respiratory tract symptoms including bronchiolitis and pneumonia. Apnoea may be the first sign of disease in children with RSV infection. The aims of this study were the identification of independent risk factors for RSV associated apnoea and the prediction of the risk for mechanical ventilation in children with RSV associated apnoea. Medical records of children younger than 12 months of age admitted with RSV infection between 1992 and 1995 to the Sophia Children's Hospital, were reviewed. Demographic parameters, clinical features and laboratory parameters (SaO₂, pCO₂ and pH) were obtained upon admission and during hospitalization. Children with and without apnoea were compared using univariate and multivariate logistic and linear regression analysis. One hundred and eighty-five patients with RSV infection were admitted of whom 38 (21%) presented with apnoea. Patients with apnoea were significantly younger, had a significantly lower temperature, higher pCO₂ and lower pH and had on chest radiographs also more signs of atelectasis. The number of patients admitted to the ICU because of mechanical ventilation and oxygen administration was significantly higher in children with RSV associated apnoea. Apnoea at admission was a strong predictor for recurrent apnoea. The relative risk for mechanical ventilation increased with the number of episodes of apnoea: 2.4 (95% CI 0.8 – 6.6) in children with one episode of apnoea (at admission) versus 6.5 (95% CI 3.3 – 12.9) in children with recurrent episodes of apnoea. Conclusions Age below 2 months is the strongest independent risk factor for RSV associated apnoea. Apnoea at admission increases the risk for recurrent apnoea. The risk for mechanical ventilation significantly increases in children who suffer from recurrent apnoea. Received: 12 May 1997 / Accepted in revised form: 22 August 1997     

Lung function testing — useless in ventilated newborns?

Several methods have been used for lung function testing in the ventilated newborn. The interest in the field has been stimulated by the recent appearance of commercially available equipment for assessment of mechanical parameters and of functional residual capacity in this group. Nevertheless, lung function testing is rarely used as a clinical routine, even such simple variables as tidal volume and minute ventilation. Among the many possible reasons for this condition, the fragile nature of the infants and the hands-off policy usually exercised, the difficulties in measuring flow accurately, and the complexity of the present methods deserve special attention. In order to change this situation more work needs to be done to elucidate basal physiology of the ventilated lung and the relationships between ventilator settings, lung function and side-effects in different conditions. If then sufficiently simple, safe and accurate methods to assess the most important functions can be offered, lung function testing would be likely to become a useful component of routine care in future neonatal intensive care.     

Chronic otitis media requiring ventilation tubes in tracheotomized ventilator dependent children

The occurrence of sinusitis and middle ear effusions has frequently been attributed to the obstruction of the sinus ostia and/or eustachian tube. In the intensive care unit setting, edema caused by the irritation from nasogastric, nasotracheal and orotracheal tubes has been associated with this pathology and has been responsible for occult sepsis in this population. Our investigation was performed to determine the risk of chronic otitis media with effusion necessitating myringotomy with tympanostomy tubes among tracheotomized, ventilator dependent children in a consecutive series of children admitted to our recently created stable ventilator unit. We retrospectively reviewed the medical records of all tracheotomized, chronically ventilator dependent children < 48 months of age who had been hospitalized in this unit from the initial opening in September 1990 to January 1993. Data collected consisted of patient demographics, gestational age, cognitive abilities, age at onset of mechanical ventilation, age at tracheostomy, age at myringotomy, presence of nasogastric and gastroenterostomy tubes and evidence of gastric-esophageal reflux. All children underwent a tracheostomy procedure subsequent to the onset of mechanical ventilation. Of these patients, 9/12 (75%) later required myringotomy with tympanostomy tube placement following the occurrence of chronic otitis media with effusion. Ventilation tubes for chronic otitis media with effusion were not required in 3 patients. Using a case control study design, we examined the need of myringotomy tubes for children requiring continuous mechanical ventilation versus those requiring night-time only ventilation. The risk of myringotomy tubes in the continuously ventilated group (9/9) was significantly greater than the risk in the intermittently ventilated group (0/3) P < 0.01. We conclude chronic otitis media with effusion is a common finding among preschool-aged children who are tracheotomized and ventilator dependent. Routine periodic ENT evaluation may be indicated in all pediatric patients who require chronic mechanical ventilation. In this specific population of children, there may be a subset of patients who would benefit from prophylactic antibiotic therapy or tympanostomy tube insertion during the duration of positive pressure ventilation. Further prospective study is warranted.     

The complexity of external acoustic detection of defects in Björk-Shiley convexoconcave heart valves

Abstract: Fractures in Björk‐Shiley convexoconcave (BScc) heart valves have raised questions about the feasibility of early diagnosis of technical defects by means of acoustic assessment. Three laboratory tests were conducted. To establish acoustic fingerprints, 66 valves with a defect, such as single‐leg fracture (SLF) or single‐leg separation (SLS), or without a defect were connected with a contact sensor and excited by dropping a small metal ball onto the outlet strut. In the second test, we simulated the valve sound propagation within the thorax. In the third test, intact, SLF, and SLS valves were placed in a mock heart immersed in a large water tank. We observed a resonance frequency corresponding with valve size and presence of defects. The second test showed that both the chest wall and the lungs created numerous reflections. This led to a substantial overlap of the original pulse frequencies and the frequencies measured. The third test confirmed that submersion of the chest in water can significantly reduce chest wall reflections. Reliable noninvasive assessment of BScc valve clicks for the presence of defects of the outlet strut is hampered by complex sound propagation within the thorax and variability of valve excitation. Acoustic fingerprints to diagnose mechanical defects should be integrated in valve design.     

Respiratory deterioration during growth hormone therapy in a case of congenital nemaline myopathy

Congenital nemaline myopathy (CNM) is generally classified as a non-progressive or slowly progressive neuromuscular disease. We describe a boy with CNM and an isolated partial growth hormone (GH) deficiency. From the onset of GH therapy his respiratory capacity deteriorated rapidly. The possible association between this deterioration and GH therapy is discussed.     

Intestinal perforation during pregnancy

Three cases of bowel perforation were encountered in pregnant women in a community hospital. Two were associated with mechanical obstruction, and one was of unknown etiology. Displacement of abdominal contents by the gravid uterus may predispose pregnant patients to intestinal obstruction in the presence of an underlying bowel abnormality, such as adhesions or malrotation. Prompt diagnosis and appropriate therapy are necessary to avoid a fatal or a severely morbid outcome.     

Appropriate positive end expiratory pressure level in surfactant-treated preterm infants

Positive end expiratory pressure (PEEP) is routinely used when ventilating preterm infants, and high levels are recommended in those with severe respiratory distress syndrome (RDS). Elevation of PEEP increases lung volume, as does surfactant administration. We postulated that in surfactant-treated infants even modest PEEP levels could result in overdistension and (CO₂) retention. To test that hypothesis, lung volume, compliance and arterial blood gases were measured in eight preterm infants (median gestational age 28 weeks, range 26–35 weeks) at three PEEP levels. The infants, all with RDS, were studied at a median time of 18 h, (range 12–68 h) after their last dose of surfactant. Infants were routinely nursed at 3 cmH₂O of PEEP, the PEEP level was then raised to 6 cmH₂O or lowered to 0 cmH₂O in random order. The new setting was maintained for 20 min; the PEEP level was then changed to the third level (0 or 6 cmH₂O) again for 20 min. At the end of each 20-min period, lung volume, compliance and blood gases were measured. Lung volume was assessed by measuring functional residual capacity (FRC) using a helium dilution technique. Compliance was measured by relating the volume change from a positive pressure inflation maintained until no further volume change occurred to the pressure drop (peak inflating pressure PEEP). Increasing PEEP from 0 to 3 cmH₂O and particularly to 6 cmH₂O resulted in increases in FRC (P < 0.05), oxygenation (ns) and paCO₂ (P < 0.02). Specific compliance (compliance/FRC) (P < 0.05) and pH (P < 0.02) fell. Conclusion Following surfactant treatment, relatively low levels of positive end expiratory pressure (≤3 cmH₂O) may be appropriate. Received: 20 April 1999 / Accepted: 26 May 1999     

Mechanically evoked perioral reflexes in premature and term human infants

Neurophysiological assessment of the preterm human neonatal oromotor system has been limited due to their fragile medical state, and methodological limitations. A new, noninvasive technology known as the actifier was developed and used to evoke perioral motor unit activity during non-nutritive suck in preterm infants. A significant ontologic trend for the early component of the perioral reflex (R1) was discovered in the context of spontaneous, centrally-patterned oromotor behavior.     

Evaluation of conventional weaning criteria in patients with acute respiratory failure

We evaluated the reliability of conventional weaning criteria from a ventilator during 33 weaning trials on 25 patients with acute respiratory failure (ARF). Of 13 criteria, a ratio of maximal voluntary ventilation to minute ventilation (MV) 2, a vital capacity 12ml·kg^–1, a spontaneous respiratory rate 25 breaths·min^–1, and a MV 10l·min^–1 appeared to be useful for predicting successful weaning outcome. However, even using those criteria, there were many falsely-negative cases. The alveolar-arterial P_{O 2} gradient 350mmHg at an Fi _{O 2} 1.0 was not useful as a predictor of weaning outcome. The present study demonstrates that conventional criteria are frequently inaccurate for predicting weaning outcomes and suggests that the use of some of these criteria may unnecessarily prolong the length of ventilator support. Since ventilation of most patients with poor oxygenation can be successfully discontinued by placing them on a continuous positive airway pressure system, these results suggest that the improvement of oxygenation is not an indispensable prerequisite for weaning from mechanical ventilators.(Okamoto K, Iwamasa H, Dogomori H, et al.: Evaluation of conventional weaning criteria in patients with acute respiratory failure. J Anesth 4: 213–218, 1990)