[Comparison of antifog methods in endoscopy. What really helps]. / Vergleich von Antibeschlagmethoden in der Endoskopie. Was wirklich hilft.

BACKGROUND: The use of a flexible or rigid fiberoptic bronchoscope belongs to the standard repertoire in anesthesiology. Besides a lack of training these procedures may be considerably compromised by endoscopic lens fogging. Several antifogging approaches are commercially available but to date no controlled studies regarding the efficacy of these devices in bronchoscopes exists. The aim of the present study was to compare the efficacy of different commercially available anti-fogging techniques for rigid and flexible bronchoscopes. MATERIALS AND METHODS: The study was performed at the department of anesthesia in a university children's hospital. An artificial airway model was created to simulate in vivo conditions with respect to airflow, temperature and atmospheric moisture. A test picture was inserted into the artificial airway for assuring a standardized view through the bronchoscopes. Antifogging efficacy of two liquid antifog solutions (Ultrastop and Anti-Fog), two antifog wipes (Lina Clear and Reso Clear) and an induction endoscope preheater system (used after one and two induction preheating phases) was assessed by video taping of the bronchoscope view of the test picture. In addition the administration of continuous oxygen airflow of 2 l min⁻¹ through the suction channel of the flexible bronchoscope was tested as an alternative method to prevent lens fogging. All final pictures were rated by 10 staff anesthesiologists who were blinded to the antifog devices used. To assess the clinical relevance of the results, ratings were classified into a 5 grade rating scale (ranging from no visualization of any structure to excellent endoscopic view allowing safe endotracheal intubation). In addition, the failure rate of each anti-fog technique was calculated. RESULTS: A total of 300 endoscopic test pictures were taken and assessed. Using the flexible bronchoscope, the use of anti-fog solution (failure rate 3 %) and Lina Clear wipes (failure rate 4%) showed the best results. In the rigid bronchoscope group Ultrastop solution (failure rate 5 %) and Lina Clear wipes (failure rate 3.5 %) showed superior results. The two-time use of the endoscope preheater system was effective using flexible (failure rate 6 %) and rigid bronchoscopes (failure rate 10 %). The application of a continuous oxygen flow of 2 l/min failed to provide a clear endoscopic view (failure rate 93.5 %). CONCLUSIONS: All commercially available antifog liquids and wipes showed slightly different reduction of lens fogging. However, other factors such as frequency of usage, the type of endoscope, hygiene properties as well as cost-effectiveness might have a substantial impact on the comparison of all tested anti-fog devices. The use of an endoscope preheater system might be a conceivable alternative method to reduce lens fogging despite the higher initial cost. However, the multiple use of the preheater system cannot be recommended at present as additional handling procedures to ensure an appropriate but safe temperature of the endoscopic tip should be provided by the manufacturer. Application of a continuous oxygen flow was shown not to be effective in preventing lens fogging using a flexible fiberoptic bronchoscope.

Ventricular size and function assessed by cardiac MRI predict major adverse clinical outcomes late after tetralogy of Fallot repair.

BACKGROUND: Factors associated with impaired clinical status in a cross-sectional study of patients with repaired tetralogy of Fallot (TOF) have been reported previously. OBJECTIVES: To determine independent predictors of major adverse clinical outcomes late after TOF repair in the same cohort during follow-up evaluated by cardiac magnetic resonance (CMR). METHODS: Clinical status at latest follow-up was ascertained in 88 patients (median time from TOF repair to baseline evaluation 20.7 years; median follow-up from baseline evaluation to most recent follow-up 4.2 years). Major adverse outcomes included (a) death; (b) sustained ventricular tachycardia; and (c) increase in NYHA class to grade III or IV. RESULTS: 22 major adverse outcomes occurred in 18 patients (20.5%): death in 4, sustained ventricular tachycardia in 8, and increase in NYHA class in 10. Multivariate analysis identified right ventricular (RV) end-diastolic volume Z >or=7 (odds ratio (OR) = 4.55, 95% confidence interval (CI) 1.10 to 18.8, p = 0.037) and left ventricular (LV) ejection fraction <55% (OR = 8.05, 95% CI 2.14 to 30.2, p = 0.002) as independent predictors of outcome with an area under the receiver operator characteristic curve of 0.850. LV ejection fraction could be replaced by RV ejection fraction <45% in the multivariate model. QRS duration >or=180 ms also predicted major adverse events but correlated with RV size. CONCLUSIONS: In this cohort, severe RV dilatation and either LV or RV dysfunction assessed by CMR predicted major adverse clinical events. This information may guide risk stratification and therapeutic interventions.

Infrared eye injury not due to radiant warmer use in premature neonates.

OBJECTIVE: Exposure to far-wavelength infrared radiation (lambda > 2000 nm) may cause corneal opacity, miosis, and delayed cataracts (onset > 30 days). Near-wavelength infrared exposure (lambda < 1000 nm) may focus on the retina, causing burns; however, early eye examinations in neonates nursed under radiant warmers have failed to reveal acute injuries. Our purpose is to report long-term ophthalmologic outcome in infants treated under radiant warmers from birth. PARTICIPANTS AND METHODS: We report findings from eye examinations in infants followed up to a median age of 2 years, 9 months (range, 1 to 75 months), for (1) 33 infants nursed exclusively under radiant warmers for up to 5 days postnatally (mean [+/- SD] birth weight, 1.16 +/- 0.24 kg; mean gestation, 30 +/- 2 weeks) and (2) 14 convection-warmed incubator-nursed infants (1.26 +/- 0.22 kg, 31 +/- 2 weeks), who were slightly more mature. MAIN RESULTS: A trend toward retinopathy of prematurity was noted as occurring more frequently in the radiant warmer-nursed infant population, and one infant in that group was blind. However, no macular burns and no permanent corneal, lens, or other anterior segment injuries were observed. CONCLUSION: Preliminary findings do not support permanent eye damage attributable to near- or far-wavelength infrared injury in neonates nursed under radiant warmers.

Accurate, noninvasive quantitation of expiratory gas leak from uncuffed infant endotracheal tubes.

Accurate measurement of expiratory gas leak from uncuffed infant endotracheal tubes is an important requirement for evaluating the rates of metabolic gas exchange by indirect calorimetry in neonates receiving mechanical ventilation. The present study reports a new, noninvasive technique for the efficient collection and analysis of expiratory gases leaked from a closed-circuit metabolic monitoring system recently described. A loose-fitting face mask is placed over the infant's endotracheal appliance and air is entrained from the mask cavity at 100 mL/min for CO2 analysis by infrared capnometry. In vitro calibration of this apparatus demonstrates a relative error of less than 5% of simulated endotracheal tube leak. In vivo application to metabolic rate assessment (using the MGM Jr. metabolic cart) in 12 intubated, ventilated infants ranging from 1.56 to 4.07 kg study weight demonstrated endotracheal tube leaks from 0.49 to 7.40% of net CO2 production, which ranged 10.67 to 70.91 mL/min (or mean 8.22 +/- 0.93 SEM mL/kg/min). The magnitude of tube leakage of mixed expiratory gases could not be predicted from endotracheal tube diameter, ventilator settings, or infant activity or posture. As new instrumentation becomes available to measure the rates of metabolic gas exchange in intubated infants, systematic evaluation of uncuffed endotracheal tube gas leaks becomes critical.

Semipermeable polyurethane membrane as an artificial skin for the premature neonate.

A thin and semipermeable polyurethane membrane adherently applied to premature neonates as an artificial skin was investigated as an atraumatic surface barrier sufficient to reduce transepidermal water loss without inhibiting natural infant skin development during the first few days of life. A sample group of 18 neonates (birth weight [mean +/- SEM] 1.39 +/- 0.12 kg, gestation [mean +/- SEM] 31 +/- 1 weeks) received two 3 X 3-cm polyurethane patches adherent over the chest and abdomen. Transepidermal water loss was measured before and after application and after membrane removal. During longitudinal study, seven infants were treated day 1 through day 4 of life and were evaluated for skin integrity 24 hours after patch removal on day 5. Polyurethane membranes produced an acute and significant reduction in transepidermal water loss for the 18 subjects: 21.1 +/- 2.0 g/m2/h before application v 10.5 +/- 1.4 g/m2/h with membranes in place (P less than .001). Immediately after patch removal, transepidermal loss returned to 22.8 +/- 3.0 g/m2/h. Throughout the first four days of life, daily measurements of water loss were significantly less: 53% to as much as 72% reduction from polyurethane-covered sites when compared with adjacent naked skin. After polyurethane membrane removal, skin development of transepidermal barrier function was comparable over both sites. Dressings did not lose adhesive or plastic properties during an extended time in either radiant warmer or incubator environments, electronic monitoring through membranes was not impeded, and adhesive injuries were not observed. An adherent, semipermeable polyurethane membrane may be effective as an atraumatic artificial barrier to prevent large transepidermal water loss and protect the skin of the premature neonate.