Reduced levels of pulmonary surfactant in COVID-19 ARDS.

To provide novel data on surfactant levels in adult COVID-19 patients, we collected bronchoalveolar lavage fluid less than 72 h after intubation and used Fourier Transform Infrared Spectroscopy to measure levels of dipalmitoylphosphatidylcholine (DPPC). A total of eleven COVID-19 patients with moderate-to-severe ARDS (CARDS) and 15 healthy controls were included. CARDS patients had lower DPPC levels than healthy controls. Moreover, a principal component analysis was able to separate patient groups into distinguishable subgroups. Our findings indicate markedly impaired pulmonary surfactant levels in COVID-19 patients, justifying further studies and clinical trials of exogenous surfactant.

[Surfactant therapy of respiratory distress syndrome].

This review gives a summary of the development of a method to measure lung surfactant on gastric aspirate at birth in premature infants with the purpose to threat respiratory distress syndrome early with targeted surfactant. Machine learning was used to create the algorithm, and a point-of-care spectrometer was constructed for use in the delivery room. The sensitivity was 91% and specificity 79% in a clinical trial. The same method was used to measure surfactant in tracheal fluid in patients with COVID-19 since lung surfactant may be diminished in these patients.

Bronchopulmonary dysplasia predicted at birth by artificial intelligence.

AIM: To develop a fast bedside test for prediction and early targeted intervention of bronchopulmonary dysplasia (BPD) to improve the outcome. METHODS: In a multicentre study of preterm infants with gestational age 24-31 weeks, clinical data present at birth were combined with spectral data of gastric aspirate samples taken at birth and analysed using artificial intelligence. The study was designed to develop an algorithm to predict development of BPD. The BPD definition used was the consensus definition of the US National Institutes of Health: Requirement of supplemental oxygen for at least 28 days with subsequent assessment at 36 weeks postmenstrual age. RESULTS: Twenty-six (43%) of the 61 included infants developed BPD. Spectral data analysis of the gastric aspirates identified the most important wave numbers for classification and surfactant treatment, and birth weight and gestational age were the most important predictive clinical data. By combining these data, the resulting algorithm for early diagnosis of BPD had a sensitivity of 88% and a specificity of 91%. CONCLUSION: A point-of-care test to predict subsequent development of BPD at birth has been developed using a new software algorithm allowing early targeted intervention of BPD which could improve the outcome.

Predicting respiratory distress syndrome at birth using fast test based on spectroscopy of gastric aspirates. 1. Biochemical part.

AIM: To develop a fast bedside lung maturity test. METHODS: Gastric aspirates obtained from premature infants contain lamellar bodies, carrying lung surfactant. To estimate lung maturity, we isolated lamellar bodies from fresh gastric aspirates by centrifugation. Erythrocytes and other cells were lysed by adding water and discarded subsequently with the supernatant. Mid-infrared spectroscopy was then performed to measure the lung maturity as lecithin-sphingomyelin ratio. Lecithin was determined as dipalmitoylphosphatidylcholine, the most surface-active phospholipid. Algorithms to measure lecithin and sphingomyelin concentrations in fresh gastric aspirates were developed on aspirates from 140 premature infants. Each gastric aspirate sample was divided into two samples: one for mass spectrometry as reference and one for spectroscopy. Development of the algorithm is described in detail in Appendix S1. RESULTS: Gastric aspirates stored at 4-5°C avoid flocculation of proteins and phospholipids in contrast to when the aspirates were frozen and thawed. Omission of freezing and concentration of the lung surfactant by centrifugation combined with diminished influence of proteins improves the spectroscopic measurement of lecithin-sphingomyelin ratio. Measurement of lecithin-sphingomyelin ratio by the new method was performed within 10-15 minutes. CONCLUSION: We present a new fast bedside lung maturity test on fresh gastric aspirate for early targeted surfactant treatment.

Predicting respiratory distress syndrome at birth using a fast test based on spectroscopy of gastric aspirates: 2. Clinical part.

AIM: To evaluate the accuracy of our new rapid point-of-care (POC) test for lung maturity. The method as we describe in an accompanying article was developed with the purpose of improving the outcome from respiratory distress syndrome (RDS). The test enables the delivery of surfactant in infants with immature lungs already at birth and ensures that infants with mature lungs are not treated unnecessarily. METHODS: Fresh gastric aspirate (GAS) was sampled at birth in a cohort of preterm infants with gestational ages ranging between 24 and 31 completed weeks for lung surfactant measurement as lecithin-sphingomyelin ratio (L/S). L/S was prospectively compared with RDS development. The clinical outcome was blinded for the investigators of L/S. The time for analysis was <15 minutes. RESULTS: GAS was obtained from 72 infants. Forty-four (61%) developed RDS. The cut-off for L/S was 3.05; predicting RDS with a sensitivity of 91% and specificity of 79%. CONCLUSION: The new improved spectroscopic L/S method of lung maturity on GAS has high sensitivity. The method is designed for use as a POC test at birth, and a spectroscopic prototype has been developed for bedside use. Clinical trials with this new lung maturity test are planned.

Rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted respiratory distress syndrome with high sensitivity.

AIM: Respiratory distress syndrome (RDS) is a major cause of mortality and morbidity in premature infants. By the time symptoms appear, it may already be too late to prevent a severe course, with bronchopulmonary dysplasia or mortality. We aimed to develop a rapid test of lung maturity for targeting surfactant supplementation. METHODS: Concentrations of the most surface-active lung phospholipid dipalmitoylphosphatidylcholine and sphingomyelin in gastric aspirates from premature infants were measured by mass spectrometry and expressed as the lecithin/sphingomyelin ratio (L/S). The same aspirates were analysed with mid-infrared spectroscopy. Subsequently, L/S was measured in gastric aspirates and oropharyngeal secretions from another group of premature infants using spectroscopy and the results were compared with RDS development. The 10-minute analysis required 10 µL of aspirate. RESULTS: An L/S algorithm was developed based on 89 aspirates. Subsequently, gastric aspirates were sampled in 136 infants of 24-31 weeks of gestation and 61 (45%) developed RDS. The cut-off value of L/S was 2.2, sensitivity was 92%, and specificity was 73%. In 59 cases, the oropharyngeal secretions had less valid L/S than gastric aspirate results. CONCLUSION: Our rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted RDS with high sensitivity.

Simultaneous determination of glucose, triglycerides, urea, cholesterol, albumin and total protein in human plasma by Fourier transform infrared spectroscopy: direct clinical biochemistry without reagents.

OBJECTIVE: Direct measurement of chemical constituents in complex biologic matrices without the use of analyte specific reagents could be a step forward toward the simplification of clinical biochemistry. Problems related to reagents such as production errors, improper handling, and lot-to-lot variations would be eliminated as well as errors occurring during assay execution. We describe and validate a reagent free method for direct measurement of six analytes in human plasma based on Fourier-transform infrared spectroscopy (FTIR). DESIGN AND METHODS: Blood plasma is analyzed without any sample preparation. FTIR spectrum of the raw plasma is recorded in a sampling cuvette specially designed for measurement of aqueous solutions. For each analyte, a mathematical calibration process is performed by a stepwise selection of wavelengths giving the optimal least-squares correlation between the measured FTIR signal and the analyte concentration measured by conventional clinical reference methods. The developed calibration algorithms are subsequently evaluated for their capability to predict the concentration of the six analytes in blinded patient samples. RESULTS: The correlation between the six FTIR methods and corresponding reference methods were 0.87

Early surfactant guided by lamellar body counts on gastric aspirate in very preterm infants.

BACKGROUND: We have developed a rapid method, based on lamellar body counts (LBC) on gastric aspirate, for identifying newborns who will develop respiratory distress syndrome with a need for surfactant supplementation. OBJECTIVE: We set out to test whether it was possible to improve the outcome when used in a clinical trial. METHODS: We randomly assigned 380 infants born at 24-29 weeks' gestation and supported with nasal continuous positive airway pressure (nCPAP) to receive surfactant guided either by LBC (intervention group) or increasing need for oxygen (control group). The primary outcome was mechanical ventilation or death within 5 days. Secondary outcomes included need for oxygen expressed by arterial to alveolar oxygen tension ratio (a/APO2) at the age of 6 h and need for oxygen at day 28. RESULTS: The primary outcomes were equal (25%) in the two groups. The intervention group had higher a/APO2 than the control group at 6 h, median 0.64 versus 0.52 (p < 0.01), and the subgroup with gestational age 26-29 weeks needed fewer days of oxygen supplementation than the controls, median 2 vs. 9 days (p = 0.01), and fewer infants needed oxygen at day 28 (p = 0.04). Furthermore, there was a tendency in the intervention group towards a shorter duration of nCPAP. Too little or viscose aspirate in 23% of the cases was a limitation of the method. CONCLUSION: Using LBC test as indicator of lung maturity and early surfactant therapy in very preterm newborns, it is possible to reduce the need for oxygen supplementation.

Airway effects of inhaled quaternary ammonium compounds in mice.

Quaternary ammonium compounds (QAC) constitute a family of widely used chemical substances. The QAC benzalkonium chloride (BAC) has caused bronchoconstriction in human beings by poorly understood mechanisms and lung damage at high concentration as shown in a single rat study. This study evaluates acute airway effects in mice after inhalation of aerosols of the QACs, BAC, hexadecyl trimethyl ammonium bromide (HTA), cetyl pyridinium chloride (CPC) and dimethyl dioctadecyl ammonium bromide (DDA). The QACs gave rise to concentration-dependent decreases in the tidal volume (VT) and a concomitant increase in respiratory rate indicating pulmonary irritation. The potencies of the QAC to induce these effects were in the order: BAC > HTA = CPC > DDA. Furthermore, inhalation of BAC and CPC aerosols gave rise to pulmonary inflammation as apparent from bronchoalveolar lavage. Stimulation of nasal trigeminal nerve endings by QAC, which may serve as a warning signal, was absent.

Prophylactic or early selective surfactant combined with nCPAP in very preterm infants.

OBJECTIVE: Early surfactant followed by extubation to nasal continuous positive airway pressure (nCPAP) compared with later surfactant and mechanical ventilation (MV) reduce the need for MV, air leaks, and bronchopulmonary dysplasia. This randomized, controlled trial investigated whether prophylactic surfactant followed by nCPAP compared with early nCPAP application with early selective surfactant would reduce the need for MV in the first 5 days of life. METHODS: A total of 208 inborn infants who were born at 25 to 28 weeks' gestation and were not intubated at birth were randomly assigned to prophylactic surfactant or nCPAP within 30 minutes of birth. Outcomes were assessed within the first 5 days of life and until death or discharge of the infants from hospital. RESULTS: Thirty-three (31.4%) infants in the prophylactic surfactant group needed MV in the first 5 days of life compared with 34 (33.0%) in the nCPAP group (risk ratio: 0.95 [95% confidence interval: 0.64-1.41]; P = .80). Death and type of survival at 28 days of life and 36 weeks' postmenstrual age and incidence of main morbidities of prematurity (secondary outcomes) were similar in the 2 groups. A total of 78.1% of infants in the prophylactic surfactant group and 78.6% in the nCPAP group survived in room air at 36 weeks' postmenstrual age. CONCLUSIONS: Prophylactic surfactant was not superior to nCPAP and early selective surfactant in decreasing the need for MV in the first 5 days of life and the incidence of main morbidities of prematurity in spontaneously breathing very preterm infants on nCPAP.

Nasal CPAP and surfactant for treatment of respiratory distress syndrome and prevention of bronchopulmonary dysplasia.

UNLABELLED: The Scandinavian approach is an effective combined treatment for respiratory distress syndrome (RDS) and prevention of bronchopulmonary dysplasia (BPD). It is composed of many individual parts. Of significant importance is the early treatment with nasal continuous positive airway pressure (nCPAP) and surfactant treatment. The approach may be supplemented with caffeine citrate and non-invasive positive pressure ventilation for apnoea. The low incidence of BPD seen as a consequence of the treatment strategy is mainly due to a reduced need for mechanical ventilation (MV). CONCLUSION: Early-postnatal treatment with nCPAP and surfactant decreases the severity and mortality of RDS and BPD. This is mainly due to a diminished use of MV in the first days of life.

Nasal CPAP has become an indispensable part of the primary treatment of newborns with respiratory distress syndrome.

Prenatal steroids, early nasal CPAP combined with early surfactant treatment followed by extubation to nasal CPAP, and if necessary mechanical ventilation is a very effective treatment of respiratory distress syndrome. This treatment package is part of the 'Scandinavian model' for treatment of very-low-birthweight infants which also comprises gentle ventilation at birth; minimal handling; 'neonatal individualized development care and assessment program'; high priority of breast feeding; and use of kangaroo method and which facilitates observation and nursing of sick premature infants and optimizes the possibility for early mother-child contact. The incidence of bronchopulmonary dysplasia seems to be less of a problem in centres preferring nasal CPAP as the primary treatment for respiratory distress syndrome.

[Epidermolysis bullosa simplex Dowling-Meara]. / Epidermolysis bullosa simplex typus Dowling-Meara.

A clinical case of epidermolysis bullosa simplex Dowling-Meara (EBS-DM) is described in a girl from birth to 23 years of age. In the neonatal period the skin symptoms were very severe, with general blister formation and Nikolsky's phenomenon. With time the symptoms improved. After puberty, the main symptoms were palmar and plantar hyperkeratosis and nail hypertrophy, plus occasional blistering. The diagnosis was verified by electron microscopy. The actual case was a new mutation, determined to be KRT-14-R125H. The incidence of EBS-DM in Denmark has been calculated as 1 in 300,000.