Measurement of end-expiratory pressure as an indicator of airway patentcy above tracheostomy in children.

The tracheostomy speaking valve is a one-way valve that closes during exhalation. It causes redirection of exhaled gas into the larynx, mouth and nasal cavity, thus enabling children with long-term tracheostomies to speak. Whether a child can tolerate the valve depends mainly on the patency of the upper airway around and above the tracheostomy tube. To measure end-expiratory pressure (EEP) at the tracheostomy tube when the speaking valve is being put in place may be a useful noninvasive tool to assess the patency of the exhalation pathway. The authors, therefore, measured EEP when the patients were first put on the speaking valves and tried to follow-up the patients thereafter. Twenty-two tracheostomized children (aged 3.2 months to 1 7years, male/female 16/6) were recruited for the present study and EEP was measured. It was found that 13 children having the EEP in the range of 2-6 cmH2O could breathe normally through the valves and later could use the valves without any problems, whereas 9 children with EEP in the range of 10-40 cmH2O demonstrated breathing difficulties and the valves had to be taken off immediately. Bronchoscopy revealed upper airway narrowing in all of those children with unsuccessful valve placements. It was concluded that EEP was exceedingly high in children with upper airway narrowing. The measurement of EEP via speaking valves can, thus, be used as an objective indicator to evaluate the patency of upper airway proximal to the tracheostomy tube.

A prospective, randomized double-blind study in children comparing two doses of nebulized L-epinephrine in postintubation croup.

OBJECTIVE: To compare the effectiveness and side effects of nebulized l-epinephrine (NLE) at a dose of 0.05 mL/kg versus 0.5 mL/kg in the treatment of postintubation croup in children. MATERIAL AND METHOD: Thirty-nine children, who developed signs and symptoms of upper airway obstruction (UAO) after extubation, were randomized to receive either 0.05 mL/kg or 0.5 mL/kg of NLE. UAO scores, vital signs (VS) and possible side effects were recorded before and at 20 and 40 minutes after the treatment. RESULTS: Twenty-one and 18 patients were allocated to the 0.05 and 0.5 mL/kg groups, respectively. Both groups showed improvements in UAO scores over time. There were no significant differences in UAO scores and VS between the groups at all time points. Side effects of epinephrine were not observed. CONCLUSION: In children with postintubation croup, the administration of NLE at the dose of 0.05 mL/kg results in similar improvements in the UAO scores, compared with the dose of 0.5 mL/kg. No complications were seen in either dose.

Dead space ventilation in volume controlled versus pressure controlled mode of mechanical ventilation.

Dead space ventilation (VD) is one of the important measurements that indicates the ventilatory efficiency of a patient who requires mechanical ventilation. However, VD is not constant and can change according to the pathology in the lungs, ventilatory patterns, perfusion and ventilation-perfusion matching. The objective of this study was to measure and compare the dead space in pediatric patients who were using pressure controlled and volume controlled modes of mechanical ventilatory by measuring the difference between arterial PCO2 and end-tidal PCO2 [P(a-ET)CO2]. From November 1996 to March 1997, 12 patients who were admitted to the pediatric intensive care unit and needed ventilator support for various reasons, were enrolled in the study. Their ages ranged from 2 to 15 years. The mechanical ventilator (Benett 7200 or Servo 900C) setting during VD measurement i.e. tidal volume, inspiratory time and positive end expiratory pressure were kept constant between changing from pressure controlled to volume controlled mode or vice versa for twenty minutes in order to allow adequate time for equilibration. The P(a-ET)CO2 between volume controlled and pressure controlled mode were 3.1 and 2.6 torr (p = 0.5) and peak inspiratory pressure were 20.0 and 17.3 torr (p = 0.01), respectively; whereas mean airway pressure, PaO2, O2 saturation and heart rate revealed no significant difference between these two modes. The authors concluded that VD in pressure controlled mode from the present study was not significantly different from VD when using volume controlled mode of mechanical ventilation in the same patient. However, VD will change according to the pathophysiologic change in respiratory system and can be used for monitoring of ventilatory pattern of patients in the pediatric intensive care unit.

Respiratory syncytial virus-associated lower respiratory tract infection in under-5-year-old children in a rural community of central Thailand, a population-based study.

The population-based cohort study on the epidemiology of respiratory syncytial virus (RSV)-associated lower respiratory tract infection (LRI) (RSV-LRI) was conducted in Takhli district from November 1998 to February 2001. The incidence of RSV-LRI was 12.6/1,000 child-year and 5.8/ 1,000 child-year during the first and second year, respectively. RSV accounted for 35.8 per cent of all LRI cases during the first year and significantly decreased to 17.5 per cent during the second year. Three-quarters of RSV-LRI occurred among children under 2 years old (76.6% during the first year and 62.2% during the second year). Most of RSV-LRI in both years occurred from July to October. Risk factor for morbidity of RSV infections were age less than or equal to 2 years (OR = 2.38, 95% CI = 1.22-4.67 p = 0.009) and sleeping with more than 3 persons in the patient's bedroom (OR = 2.92,95% CI = 1.42-6.00, p = 0.002). Most RSV-LRI (63.9%) were clinically diagnosed as having pneumonia. No RSV-LRI deaths were detected. During the first year, RSV subtype B was predominate, in contrast to the second year when subtype A was more predominate. Further research to determine the annual change in subtype of RSV-LRI and correlation of severity of disease with specific subtypes needs to conducted in order to prepare for the future introduction of a vaccine.