Search PubMed⌕ Search

Biomedical subjects

Jürg Hammer

Publications and source records attributed to Jürg Hammer.

18 recordsLinked to original sources

Indications for tracheostomy in children.

Vaccination programs, improvements in material engineering and anaesthetic skills have dramatically reduced the number of emergency tracheostomies performed for acute upper airway obstruction. Today, the indication to tracheotomise a child is generally ruled by the anticipation of long-term (cardio)respiratory compromise due to chronic ventilatory or, more rarely, cardiac insufficiency, or by the presence of a fixed upper airway obstruction that is unlikely to resolve for a significant period of time. As many of the younger candidates for tracheostomy have complex medical conditions, the indication for this intervention is often complicated by ethical, funding and socio-economic concerns that necessitate a multidisciplinary approach. Unfortunately, these considerations are frequently not made until the first catastrophe has occurred, even in those patients in whom imminent cardiorespiratory failure has been foreseeable. Non-invasive ventilation via a face mask and newer developments such as the in-exsufflator device have gained importance as an alternative to tracheostomy in selected patients.

Airway Obstruction↗

Decrease of functional residual capacity and ventilation homogeneity after neuromuscular blockade in anesthetized young infants and preschool children.

BACKGROUND: Based on age-dependent differences in pulmonary mechanics, the effect of neuromuscular blockade may differ in infants compared with older children. The aim of this study was to determine the impact of neuromuscular blockade and its reversal by positive end-expiratory pressure (PEEP) on functional residual capacity (FRC) and ventilation distribution in young infants and preschool children. METHODS: The authors studied 14 infants (aged 0-6 months) and 25 preschool children (aged 2-6 yr). FRC and lung clearance index were calculated. Measurements were taken (1) after intubation, (2) during neuromuscular blockade, and (3) during neuromuscular blockade plus application of PEEP (3 cm H2O). RESULTS: Functional residual capacity (mean +/- SD) decreased from 21.3 +/- 4.7 ml/kg to 12.2 +/- 4.8 ml/kg (P < 0.001) during neuromuscular blockade in infants and from 25.6 +/- 5.9 ml/kg to 23.0 +/- 5.3 ml/kg (P < 0.001) in preschool children. With the application of PEEP, FRC increased to 22.3 +/- 5.9 ml/kg (P = 0.4829, compared with baseline) in infants and 28.2 +/- 5.8 ml/kg (P < 0.001) in children. The lung clearance index increased after neuromuscular blockade, whereas baseline values were regained after the application of PEEP. The changes induced by neuromuscular blockade were significantly greater in infants compared with preschool children (P < 0.001). CONCLUSIONS: Although the use of neuromuscular blockade decreased FRC and ventilation distribution substantially in both groups, the changes were more pronounced in young infants. With PEEP, FRC increased and ventilation homogeneity was restored. These results provide a rationale to use PEEP in anesthetized, paralyzed infants and children.

Anesthesia↗

Disease control in asthmatic children seen in private practice in Switzerland.

BACKGROUND: Asthma is the most common chronic childhood disease in Switzerland with a prevalence of 10%. Asthma has a high economic burden accounting for high medical costs. Assessment of disease control is likely to be of help in the implementation of strategies to improve asthma. Therefore, we aimed to evaluate asthma control and therapy regimens among children in private practice. METHODS: We assessed asthma control as well as therapy regimens in 575 asthmatic children in an experience programme in Switzerland by using an abbreviated questionnaire based on the asthma control questionnaire and the child health questionnaire on Visit 1 and Visit 2. RESULTS: Good asthma control at Visit 1 was only present in 25.7% of asthmatic children. Occasional asthma symptoms, limitation of physical activity, nocturnal awakening and anxiety of the parent was present in 80.5%, 41.2%, 46.8% and 57% of the children, respectively. After adjustment of therapy regimens at Visit 1, mainly by adding a leukotriene receptor antagonist, asthma control was reported to be much better in 53.4% of the children at Visit 2. CONCLUSIONS: As asthma control is inadequately achieved within a major portion of asthmatic children, it is imperative to find measures to improve asthma control and hence, to reduce the burden of disease.

Asthma↗

Swiss physicians' practices of long-term mechanical ventilatory support of patients with Duchenne Muscular Dystrophy.

INTRODUCTION: Previous studies have shown that long-term ventilation (LTV) is still not routinely offered to or discussed with patients with Duchenne Muscular Dystrophy (DMD). This is in contrast to the increasing evidence that these interventions can successfully improve quality of life and prolong survival of affected individuals. AIM: The aim of this survey was to describe the clinical practice and the attitudes of Swiss physicians in the respiratory follow up of DMD individuals and to understand better the current provision of respiratory services in Switzerland. Another aim was to explore the contentment of the patients about the provision of information on LTV. METHODS: Postal questionnaires requesting information on the current practice of respiratory care were sent to physicians, including pulmonologists and neurologists known or suspected to be involved in the care of children and adults with DMD. 26 of 30 (87%) physicians returned the questionnaire. A second questionnaire was sent to 90 DMD patients of whom 43 (48%) returned the questionnaire. RESULTS: 88% of the physicians indicated to discuss the option of LTV with their patients and families, but 50% of the surveyed physicians start such discussions only after the patient has already developed respiratory failure. Regular pulmonary function assessments are performed by the majority physicians in DMD patients, but only 50% of the physicians perform regular sleep studies to detect sleep disordered breathing. CONCLUSION: The majority of Swiss physicians involved in the care of DMD patients disclose information on LTV to DMD patients, but commonly late in the disease course after respiratory problems have developed. The current routine of respiratory follow-up of DMD patients seems insufficient, at least with respect to early detection of nocturnal hypoventilation.

Adolescent↗

Mycobacterium bohemicum--a cause of paediatric cervical lymphadenitis.

We report on two toddlers suffering from Mycobacterium bohemicum lymphadenitis. Acid-fast bacilli were cultured from submandibular lymph nodes and identified by molecular methods as Mycobacterium bohemicum. Surgical treatment was successful and complemented by oral treatment with clarithromycin and rifampicin.

Anti-Bacterial Agents↗

Inhaled nitric oxide therapy in neonates and children: reaching a European consensus.

Inhaled nitric oxide (iNO) was first used in neonatal practice in 1992 and has subsequently been used extensively in the management of neonates and children with cardiorespiratory failure. This paper assesses evidence for the use of iNO in this population as presented to a consensus meeting jointly organised by the European Society of Paediatric and Neonatal Intensive Care, the European Society of Paediatric Research and the European Society of Neonatology. Consensus Guidelines on the Use of iNO in Neonates and Children were produced following discussion of the evidence at the consensus meeting.

Administration, Inhalation↗

The use of cuffed versus uncuffed endotracheal tubes in pediatric intensive care.

OBJECTIVE: To report our experience with cuffed endotracheal tubes (ETT) in a large cohort of critically ill children. Study design We prospectively collected data over a 1-year period concerning long-term intubation on 860 critically ill children admitted to our intensive care unit. Tube sizes were dictated by the modified Cole formula for uncuffed ETT (age [y]/4+4 mm ID) and chosen one-half size less for cuffed ETT. Cuff pressure was regularly monitored to maintain a small leak at peak inspiratory pressure. The choice of ETT was made by the physician responsible for the initial airway management. RESULTS: There were 597 patients in the first 5 years of life, with 210 having cuffed ETT. There were no significant differences in the use of racemic epinephrine for postextubation subglottic edema, the rate of successful extubation or the need for tracheotomy between those with cuffed and uncuffed ETT in any age group. CONCLUSIONS: Our data suggest that the traditional teaching in pediatric anesthesia and intensive care, including current pediatric life support recommendations, need to be reviewed for children to benefit from the advantages of modern low-pressure cuffed ETT during critical illnesses.

Adolescent↗

Acquired upper airway obstruction.

Acquired upper airway obstruction is a common cause of respiratory emergencies in children. Most pathologic processes that result in upper airway compromise are a consequence of infection, trauma or aspiration. Today, many of the infectious causes of upper airway obstruction have lost their threat as a result of the progress made in preventing and treating these infections. Prompt recognition and appropriate management of the child presenting with upper airway obstruction remains critical, because certain causes can progress rapidly from a mild to a potentially life-threatening disease state. A correct diagnosis can often be made by history and physical examination, but additional studies may be useful in selected cases. The child's clinical appearance is the most reliable indicator of severity, and measurable signs are of less value. If respiratory failure is imminent, airway protection and endoscopy for definitive diagnosis may have priority over any other therapeutic or diagnostic procedure.

Airway Obstruction↗

Nasal nitric oxide measurements to screen children for primary ciliary dyskinesia.

STUDY OBJECTIVE: To examine the usefulness of exhaled and nasal nitric oxide (NO) measurements to detect primary ciliary dyskinesia (PCD) in children. DESIGN AND METHODS: The study population consisted of 34 children with symptoms suggestive of PCD who were previously referred to our pediatric university respiratory disease clinic for a diagnostic workup including analysis of ciliary structure and function by respiratory mucosal biopsy. PCD was diagnosed in 17 of the 34 children according to the ciliary biopsy results. Measurements of nasal and exhaled NO were performed according to European Respiratory Society and American Thoracic Society guidelines in the patients with and without biopsy-proven PCD, and also in 24 healthy age-matched subjects. RESULTS: Nasal NO was significantly lower in those children with proven PCD (geometric mean; 13.7 parts per billion [ppb]), compared to those who had negative biopsy results (132.7 ppb) and healthy control subjects (223.7 ppb). The measurement of nasal NO in our study population showed, below a cut-off level of < 105 ppb, a specificity of 88% for PCD, and positive predictive value of 89%. Nasal NO above a cut-off level of 105 ppb excluded PCD with a 100% certainty. The lower levels of exhaled NO in patients with PCD did not reach statistical significance. CONCLUSION: The measurement of nasal NO appears to be a useful tool to screen children for PCD and to exclude this disease in those with high nasal NO levels.

Body Fluids↗

Measurement of lung volume in mechanically ventilated monkeys with an ultrasonic flow meter and the nitrogen washout method.

OBJECTIVE: Measurement of functional residual capacity (FRC) during mechanical ventilation is important to standardise respiratory system compliance and adjust the ventilator settings to optimise lung recruitment. In the present study we compared three methods to measure FRC. DESIGN: The bias flow nitrogen washout technique (FRC(N2MC)), the multiple breath nitrogen washout (FRC(MBNW)) and the multiple breath sulphur-hexafluoride washout using the molar mass signal of an ultrasonic flow meter (FRC(MBSF6)) were compared in six adult monkeys after endotracheal intubation and during spontaneous breathing and mechanical ventilation at three different positive end-expiratory pressure (PEEP) levels of 0, 5 and 10 cmH2O. SETTING: Animal research laboratory. RESULTS: We found good agreement between all three methods and they all accurately measured changes in FRC when PEEP was increased. The coefficients of variance of the three measurement techniques were in the same range (1.3-9.2%). CONCLUSION: The measurement of the tracer gas concentration with the molar mass signal of the ultrasonic flow meter provides a good and simple alternative to respiratory mass spectrometer for FRC measurements in ventilated subjects.

Airway Resistance↗

Effect of forced deflation maneuvers upon measurements of respiratory mechanics in ventilated infants.

OBJECTIVE: To determine the effect of forced deflation maneuvers on respiratory mechanics and to assess the reproducibility of such measurements in intubated infants with lung disease. DESIGN AND SETTING: Prospective study in the pediatric intensive care unit of a university children's hospital. PATIENTS: Ten clinically stable infants requiring mechanically assisted ventilation for acute pulmonary disease, mean age 5.9 months (1-18), mean weight 5.8 kg (3.2-13). INTERVENTIONS: Two sets of measurements of compliance (Crs) and resistance (Rrs) were obtained at 20-min intervals both before and after +40/-40 cmH(2)O forced deflation maneuvers. Forced deflation measurements were repeated at the end of the study. RESULTS: . Forced deflation caused a significant increase in Crs from 0.53+/-0.09 and 0.58+/-0.11 ml/cmH(2)O/kg to 0.71+/-0.11 and 0.68+/-0.11 ml/cmH(2)O/kg. Rrs measurements did not differ. The low coefficients of variation for repeated measures of the baseline measurements (Crs 4.2+/-0.5%, Rrs 7.1+/-0.8%, for forced vital capacity 8.6+/-2.5%, maximum expiratory flows at 25% vital capacity 16.0%+/-3.3%) confirmed the good reproducibility during stable conditions. CONCLUSIONS: Inflation and deflation maneuvers affect subsequent measurements of respiratory system compliance but not measurements of maximum expiratory flow-volume relationships in intubated infants, probably through recruitment of lung volume. Careful interpretation and planning of the sequence of infant pulmonary function testing is necessary to reassure that changes are not related to short-term alterations in volume history.

Airway Resistance↗

Congenital central hypoventilation syndrome associated with Hirschsprung's disease and neuroblastoma: case of multiple neurocristopathies.

We report on a male infant with the rare combined occurrence of congenital central hypoventilation syndrome (CCHS or Ondine's curse), Hirschsprung's disease (HD), and neuroblastoma. Current therapeutical options leave no doubt that children with isolated forms of CCHS, HD, or neuroblastoma must be treated, but management decisions and the ethical dilemma become more difficult with the presence of multiple neurocristopathies. Our patient was dependent on mechanical ventilation and total parenteral nutrition, when a neuroblastoma was diagnosed at age 5 months. We initiated an attempt at curative chemotherapy. The tumor failed to respond to recommended chemotherapeutic regimens, and the patient died at 11 months of age. We emphasize the importance of screening CCHS patients for associated illnesses such as neuroblastoma and ganglioneuroblastoma at time of diagnosis.

Abdominal Neoplasms↗