Bettina Bohnhorst

Pulse oximeters' reliability in detecting hypoxemia and bradycardia: comparison between a conventional and two new generation oximeters.

Objective: Pulse oximeters are increasingly used for patient monitoring; however, they are traditionally very prone to motion artifact. Newly developed instruments have lower false alarm rates. We wanted to know whether this is achieved at the expense of an increased proportion of false negative alarms such as missed or delayed identification of hypoxemia and/or bradycardia. Design: Observational study. Setting: Neonatal intensive care unit. Patients: A total of 17 unsedated preterm infants (median gestational age at birth, 25 wks; range, 24‐30 wks). Intervention: Long‐term recordings of transcutaneous partial pressure of oxygen (PTcO2), heart rate, pulse oximeter saturation (SpO2), and pulse rate from a conventional oximeter and two new generation oximeters. Measurements: Recordings were analyzed for episodes with PTcO2 <40 torr or with heart rate <80 beats/min for >5 secs. Hypoxemia was considered identified if SpO2 had fallen to <85% within 2 mins of PTcO2 reaching 40 torr, and bradycardia was considered identified if pulse rate had fallen to <80 beats/min within 2 mins of the heart rate reaching this threshold. Main Results: A total of 202 falls in PTcO2 to <40 torr occurred; 174 (86%) were identified by all three oximeters. Of the remaining episodes, manual analysis of red and infrared absorption signals confirmed that SpO2 had indeed been <85% for ≥10 secs in 11 episodes; therefore, these episodes should have been identified by all three oximeters. None of these had been missed by the conventional oximeter, but 10 (5.4% of the total) were missed by one of the new generation instruments (Nellcor), and one (0.5%) was missed by the other (Masimo). Of 54 bradycardias, only 14 were identified by all three oximeters; 17 (32%) were missed by the conventional, 37 (69%) by the Nellcor, and 4 (7%) by the Masimo instrument. Conclusion: One of the two new generation instruments investigated in this study missed 5.4% of hypoxemic episodes and 69% of bradycardias. It thus appears that this instruments reduced false alarm rate is achieved at the expense of an unreliable and/or delayed identification of hypoxemia and bradycardia. The other instrument identified both conditions equally as or more reliably than a conventional pulse oximeter.

Nifedipine aggravates cyclosporine A-induced gingival hyperplasia

Gingival hyperplasia is a common side-effect of immunosuppression with cyclosporine A. Nifedipine is often used to control hypertension in kidney graft recipients. Analysis of gingival status in 106 children transplanted at our centre, and treated either with azathioprine, cyclosporine A or both, revealed significantly higher degrees of gingival overgrowth in those children receiving a combination of cyclosporine A and nifedipine compared with those children treated with cyclosporine A or nifedipine alone. Seven children undergoing gingivectomy at our centre over the past few years had received this combination. After a change in the antihypertensive regimen, avoiding long-term nifedipine medication, and improved dental care with chlorhexidine gel, we noted a reduction in the degree of gingival hyperplasia. In the majority of patients, nifedipine could be replaced by a single drug, usually hydralazine. We therefore recommend avoiding calcium channel blockers in the long-term management of hypertension in patients receiving cyclosporine.

Detection of small bolus volumes using multiple intraluminal impedance in preterm infants

Background Multiple intraluminal impedance (MII) is a new technique that allows detection of reflux and swallows via changes in impedance caused by a liquid bolus inside the esophagus. The method is independent of pH. The authors studied the ability of this technique to detect the small bolus volumes potentially occurring in young infants. Methods Ten preterm infants (median gestational age at birth, 33 weeks; range, 25–36 weeks; age at study, 9 days; range, 2–39 days) underwent 10 instillations each of 0.1 mL to 0.5 mL saline while MII was recorded via a 2.4-mm nasogastric catheter. MII signals were analyzed for swallows, defined as a decrease in impedance starting within 1 minute. From the liquid instillation in the most proximal channel and extending downward, impedance changes during these induced swallows were compared with those occurring during spontaneous swallows. Results All 100 liquid instillations resulted in a typical impedance pattern, occurring after a median interval of 4.4 seconds (range, 1.8–8.9 seconds). The decrease in impedance was more pronounced than after spontaneous swallows (30% vs. 24%, P < 0.03) and extended downward more rapidly (12.3 cm/s vs. 5.8 cm/s, P < 0.01). Conclusion Bolus transport of small liquid volumes can be detected via MII.

Epidemic Microclusters of Blood-Culture Proven Sepsis in Very-Low-Birth Weight Infants: Experience of the German Neonatal Network

Introduction We evaluated blood culture-proven sepsis episodes occurring in microclusters in very-low-birth-weight infants born in the German Neonatal Network (GNN) during 2009–2010. Methods Thirty-seven centers participated in GNN; 23 centers enrolled ≥50 VLBW infants in the study period. Data quality was approved by on-site monitoring. Microclusters of sepsis were defined as occurrence of at least two blood-culture proven sepsis events in different patients of one center within 3 months with the same bacterial species. For microcluster analysis, we selected sepsis episodes with typically cross-transmitted bacteria of high clinical significance including gram-negative rods and Enterococcus spp. Results In our cohort, 12/2110 (0.6%) infants were documented with an early-onset sepsis and 235 late-onset sepsis episodes (≥72 h of age) occurred in 203/2110 (9.6%) VLBW infants. In 182/235 (77.4%) late-onset sepsis episodes gram-positive bacteria were documented, while coagulase negative staphylococci were found to be the most predominant pathogens (48.5%, 95%CI: 42.01–55.01). Candida spp. and gram-negative bacilli caused 10/235 (4.3%, 95%CI: 1.68% –6.83%) and 43/235 (18.5%) late-onset sepsis episodes, respectively. Eleven microclusters of blood-culture proven sepsis were detected in 7 hospitals involving a total 26 infants. 16/26 cluster patients suffered from Klebsiella spp. sepsis. The median time interval between the first patient’s Klebsiella spp. sepsis and cluster cases was 14.1 days (interquartile range: 1–27 days). First patients in the cluster, their linked cases and sporadic sepsis events did not show significant differences in short term outcome parameters. Discussion Microclusters of infection are an important phenomenon for late-onset sepsis. Most gram-negative cluster infections occur within 30 days after the first patient was diagnosed and Klebsiella spp. play a major role. It is essential to monitor epidemic microclusters of sepsis in surveillance networks to adapt clinical practice, inform policy and further improve quality of care.

Patient with trisomy 6 mosaicism

Trisomy 6 and trisomy 6 mosaicism were found in chorionic villi cell culture and short term incubation in a prenatal diagnosis at 12 weeks of gestation in a pregnancy with a growth retarded fetus showing nuchal translucency. The child was born in the 25th gestational week with a number of malformations including heart defects, deep-set ears, cleft right hand, cutaneous syndactylies, and overlapping toes of irregular shape and length. Trisomy 6 was not found in peripheral blood lymphocytes but was confirmed in umbilical cord fibroblasts. Currently, at the age of 2-3/4 years, the development of the child is relatively normal despite considerable growth delay. At the age of two years, she developed a papular erythema clinically suggestive of epidermal nevi. Cytogenetic analysis of fibroblast cultures derived from skin from a right hand finger and the inguinal area confirmed the presence of a trisomy 6 mosaicism. This is the first observation of a liveborn with trisomy 6 mosaicism.

Prenatal diagnosis of congenital alveolar proteinosis (surfactant protein B deficiency)

We report on the DNA‐based prenatal diagnosis of congenital pulmonary alveolar proteinosis in a family in which alveolar proteinosis was associated with surfactant protein B (SP‐B) deficiency. The parents had lost an eight‐week‐old female child due to this fatal disorder. The affected child was homozygous and both parents were heterozygous for a frame‐shift mutation in codon 121 of the surfactant protein B gene (SFTP3‐gene). Chorionic villus sampling (CVS) was performed in two subsequent pregnancies. DNA analysis revealed homozygosity for the codon 121 mutation in the first fetus, and the pregnancy was terminated. Homozygosity for the parental wild‐type alleles was detected in the following prenatal diagnosis, and a healthy child has been born.

Closed versus Open Endotracheal Suctioning in Extremely Low-Birth-Weight Neonates: A Randomized, Crossover Trial

Background: Endotracheal suctioning, which is frequently necessary in mechanically ventilated patients, might cause complications, especially in patients with compromised lung function such as extremely low-birth-weight (ELBW) neonates. Objectives: To investigate whether closed endotracheal suctioning (CS) reduces the frequency of hypoxemia and bradycardia in ELBW neonates compared to open suctioning (OS). Methods: In a randomized, crossover trial, 15 ventilated ELBW neonates (mean birth weight 655 g) underwent suctioning with both techniques. Data on oxygen saturation (Spo2), heart rate (HR), arterial blood pressure, arterial blood gases, duration of the suctioning procedure and recovery time were collected. Statistical analysis was done using the SPSS t test for paired samples. Results: The mean frequency of hypoxemia <85% was significantly decreased (p = 0.012) during CS (0.5) versus OS (1.1). The mean minimum Spo2 was significantly higher (p = 0.012) during CS (87%) compared to OS (84%), and a significantly less steep drop in mean Spo2 (p = 0.007) (CS: –5%, OS: –8%) was found. Mean arterial Po2 (p = 0.035; CS: 59 mm Hg, OS: 53 mm Hg) and mean oxygenation ratio (p = 0.016; CS: 197, OS: 171) were significantly higher after CS. No significant differences were found in HR, incidence or duration of bradycardia, recovery time, arterial blood pressure, duration of suctioning, number of complications, or duration of hypoxemia. Conclusion: CS was superior to OS on oxygenation values. To prove its overall superiority, further research is required. So, in this group of patients, CS should currently be administered on an individual basis.

Severe methemoglobinemia caused by continuous lidocaine infusion in a term neonate

Neonates and young infants are especially prone to develop drug-induced methemoglobinemia. Therefore, lidocaine is not licensed as local anesthetic in children below the age of 3 months. However, its systemic use is advocated for neonatal seizures. Cardiac arrhythmia has been reported as sole major side effect. Here we report a case of severe methemoglobinemia caused by continuous infusion of lidocaine in a term neonate with neonatal seizures. The increase of methemoglobin up to 13.8% was accompanied by hypoxemia and cyanosis, necessitating additional inspired oxygen and CPAP ventilation. After stopping lidocaine infusion methemoglobin levels fell and the neonate could be weaned from ventilation. Neonates treated with lidocaine for seizures must be monitored for the occurrence of methemoglobinemia.

Prescription of Home Oxygen Therapy to Very Low Birth Weight Infants in Germany A Nationwide Survey

Objective. There is no consensus on prescription of home oxygen therapy to infants in Germany. We hypothesized that this causes considerable variability in prescribing home oxygen to infants. Study Design. A structured questionnaire involving management of home oxygen therapy was sent to all German pediatric departments (n = 293). Results. Response rate was 84% (247/293). SpO2 cutoff values below which oxygen therapy was considered indicated showed a wide range (80% to 94%, mean 90%). Respondents admitting >50 very low birth weight infants annually significantly more frequently prescribed home oxygen (P < .001) and aimed for SpO2 levels closer to the physiological range than those admitting less very low birth weight infants (P = .046). Conclusion. Management of pediatric home oxygen therapy is diverse in Germany. Optimal SpO2 targets have to be further investigated by controlled studies and German guidelines should be established. Until then practice should abide by existing foreign guidelines.

Unilaterales pulmonales Emphysem : Nichtinvasives Therapiekonzept bei 2 frühgeborenen

ZusammenfassungHintergrund. Das pulmonale interstitielle Emphysem ist eine schwerwiegende Komplikation des neonatalen Atemnotsyndroms und gilt als Risikofaktor für das Auftreten von Hirnblutung und chronischer Lungenerkrankung. Bei bilateralen Formen gilt die Hochfrequenzoszillationsbeatmung als möglicher Therapieansatz, bei der unilateralen Form sind die selektive Beatmung der kontralateralen Lunge oder die operative Resektion der befallenen Lungenabschnitte gängige, jedoch relativ aggressive therapeutische Optionen. Fallbericht. Wir berichten über 2 Frühgeborene mit unilateralem pulmonalem interstitiellem Emphysem, welches sich unter einer nichtinvasiven Therapie mit konsequenter Lagerung auf die betroffene Seite und einer antiinflammatorischen Behandlung mit Dexamethason vollständig zurückbildete. Diskussion. Eine Minderbelüftung der kranken Lunge aufgrund von Kompression durch das Gewicht der benachbarten Strukturen bewirkte in Kombination mit dem antiinflammatorischen Effekt der Steroide eine Rückbildung des pulmonalen interstitiellen Emphysems. Ob eine alleinige Lagerungstherapie zum gleichen Erfolg geführt hätte, muss offen bleiben. Wegen der offensichtlichen Vorteile eines konservativen Managements sollte beim unilateralen interstitiellen Emphysem ein Therapieversuch mit Seitenlagerung und ggf. antiinflammatorischer Behandlung erwogen werden.SummaryBackground. Pulmonary interstitial emphysema is a serious complication of neonatal respiratory distress syndrome carrying an increased risk of intraventricular haemorrhage and development of chronic lung disease of prematurity. Management of unilateral PIE usually includes aggressive methods such as surgical removal of the affected lung tissue or selective intubation of the contralateral bronchus. Case report. We report two cases of unilateral interstitial emphysema resolving completely with non-invasive management consisting of strict lateral decubitus positioning of the affected lung in combination with antiinflammatory therapy. Discussion. We feel that the management of unilateral interstitial emphysema presented in these cases is minimally invasive yet effective. We could not determine whether positional treatment alone would have been equally effective. Although the optimal choice of treatment clearly depends on the condition of the individual patient, we suggest to consider this approach in cases of unilateral interstitial emphysema.