News review 2. Dr Deorari & Dr JEEVA Sankar share their views on CPAP What is new !....
CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP): - WHAT IS NEW?
Continuous positive airway pressure (CPAP) is a form of noninvasive ventilation that is becoming increasingly popular as a method of respiratory support in sick neonates. CPAP, as the term implies, refers to the application of positive pressure to the airways of a spontaneously breathing infant throughout the respiratory cycle. Here, we shall review the current literature regarding the early use of CPAP as a primary modality for management of respiratory distress.
The major indication for CPAP is respiratory distress syndrome (RDS), a condition usually seen in preterm infants and characterized by surfactant deficiency that results in alveolar collapse. CPAP helps by reopening the collapsed alveoli and by preventing the collapse of unstable alveoli during expiration. CPAP is now the primary mode of respiratory support in these infants and early initiation of CPAP has been shown to reduce the need for intubation and mechanical ventilation. Recently, Swietlinski J et al did a prospective analysis to evaluate whether aggressive use of nasal CPAP results in better clinical outcomes. They collected data for a period of 2 years from 57 neonatal centers in Poland. They found that tracheal intubation was avoided in 78% of infants with the use of CPAP. The relatively new practice (for their country) was well accepted and was also found to be safe (1).
Since the major risk factor for chronic lung disease (CLD) is the need for mechanical ventilation, the strategy of early CPAP might also result in reduced incidence of CLD. Initial studies had shown encouraging results with reduced incidence of CLD. Vanpee et al compared the ventilatory styles between two neonatal units (one in Boston where all infants were intubated and another in Stockholm where delivery room CPAP was used mostly). Preterm infants (< 28 weeks gestation) with respiratory distress were studied. Though the risk for CLD at 36 weeks was not different between the two centers, fewer infants were on oxygen support at 40 weeks in Stockholm center suggesting that early aggressive CPAP could have a beneficial role in outcome (2).
CPAP, being simple and inexpensive (especially indigenous bubble CPAP), could play a critical role in resource restricted settings like India where most of the neonates are still being cared for in primary health facilities and small hospitals. Indeed this strategy along with administration of antenatal steroids may prove to be a boon in future for preterm infants born in such settings. A recent study from Australia has shown that bubble CPAP therapy reduced the need for up-transfer of infants with respiratory distress in non-tertiary centers. For every 6 infants treated with CPAP, there was an estimated cost saving of $10,000 (3).
Though CPAP is usually safe, at supra-optimal pressures it could decrease the venous return and the cardiac output (by increasing the intra thoracic pressure). Concerns have also been raised in the past regarding the increase in intracranial pressure (ICP) and the resultant decrease in cerebral perfusion pressure with application of CPAP. Recently, Dani et al evaluated the brain hemodynamic effects of nasal CPAP in preterm infants using near-infrared spectroscopy (NIRS) and concluded that at 2-6 cm H2O pressure levels CPAP did not affect cerebral oxygenation and cerebral blood volume (4).
To conclude, the recent evidence reiterates the following facts:
1. Introduction of Infant Flow nasal continuous airway pressure as the standard of practice in Poland: the initial 2-year experience.
Swietlinski J, Bober K, Gajewska E, Helwich E, Lauterbach R, Manowska M, Maruszewski B, Szczapa J, Hubicki L.
Pediatr Crit Care Med 2007;8:109-14.
OBJECTIVE: The aim of this prospective study was to evaluate whether a change in the standard of newborn care for respiratory insufficiency by widely introducing more aggressive use of nasal continuous airway pressure (nCPAP) and including Infant Flow technology would result in satisfactory outcomes.
DESIGN: Prospectively defined analysis
SETTING: Fifty-seven secondary and tertiary care neonatal centers in Poland
PATIENTS: Patients were 1,299 newborns
MEASUREMENTS AND MAIN RESULTS: We carried out a prospectively defined analysis of 1,299 newborns included in the program between August 1, 2003, and April 30, 2005. The inclusion criterion was the occurrence of symptoms of respiratory failure irrespective of its etiology. Respiratory support was provided with the use of the Infant Flow Advance Driver. The analysis was made on data from prospectively designed questionnaires completed following each infant's treatment. Infants were placed into categories based on clinical indication for use. The primary end point was avoiding tracheal intubation. A high rate of acceptance of the new practice was observed across the substantial demographic and clinical diversity of newborns. Tracheal intubation was avoided in 78% of infants treated electively with nCPAP. Of those being weaned from mechanical ventilation, 61.2% were successfully weaned. Related complications were low (1.4% pneumothorax, 12% nasal injuries).
CONCLUSIONS: The new method of nCPAP with Infant Flow was adopted as standard practice in Poland. We monitored its safety and effectiveness over a 2-yr period and found it to be safe and effective as implemented. Additional research is still needed to determine the optimum patient population, strategy for use, and devices.
2. Resuscitation and ventilation strategies for extremely preterm infants: a comparison study between two neonatal centers in Boston and Stockholm.
Vanpee M, Walfridsson-Schultz U, Katz-Salamon M, Zupancic JA, Pursley D, Jonsson B.
Acta Paediatr. 2007; 96:10-6.
AIM: To evaluate if different resuscitation and ventilatory styles exist between two neonatal units, and if the less aggressive approach has a beneficiary effect on BPD outcome.
METHOD: Inborn infants delivered at a gestational age <28 weeks were retrospectively studied (Boston = 70 and Stockholm = 102). Data were collected from birth to discharge or to 40 weeks.
RESULTS: The study groups were similar with regard to gestational age, birth weight, gender and CRIB score, whereas SNAPPE-II score was greater in Stockholm and prenatal steroids were given less frequently in Boston. In Stockholm, continuous positive airway pressure (CPAP) was applied in the delivery room for 56% of the infants and the prevalence of infants not requiring intubation or mechanical ventilation (MV) during the first week of life was 22%. In Boston all infants were initially intubated. Subsequently, CPAP was used less often, and higher mean airway pressures (MAWPs) were applied during the first 4 weeks of life. Mortality and moderate/severe BPD at 36 weeks were similar; however, at 40 weeks oxygen supplementation was more frequent in Boston. Site was a predictor for moderate/severe BPD or death at 40 weeks.
CONCLUSION: Practice style differences exist and the less aggressive approach with more CPAP administration was successful. It did not decrease the risk for BPD at 36 weeks; however, at 40 weeks, fewer infants were on oxygen support, and a strong association was found between site, MAWP or MV with pulmonary morbidity indicating that CPAP could have a beneficiary role in outcome.
3. Continuous Positive Airway Pressure Therapy for Infants with Respiratory Distress in Non-Tertiary Care Centers: A Randomized, Controlled Trial
Buckmaster AG, Arnolda G, Wright IM, Foster JP, Henderson-Smart DJ
Objective: Our objective was to determine whether continuous positive airway pressure therapy would safely reduce the need for up-transfer of infants with respiratory distress from non-tertiary centers. Methods: We randomly assigned 300 infants at >30 weeks of gestation with respiratory distress to receive either Hudson prong bubble continuous positive airway pressure therapy or head-box oxygen treatment (standard care). The primary end point was �up-transfer or treatment failure.� Secondary end points included death, length of nursery stay, time receiving oxygen therapy, cost of care, and other measures of morbidity.
Results: Of 151 infants who received continuous positive airway pressure therapy, 35 either were up-transferred or experienced treatment failure, as did 60 of the 149 infants given headbox oxygen treatment. There was no difference in the length of stay or the duration of oxygen treatment. For every 6 infants treated with continuous positive airway pressure therapy, there was an estimated cost saving of $10 000. Pneumothorax was identified for 14 infants in the continuous positive airway pressure group and 5 in the headbox group. There was no difference in any other measure of morbidity or death.
Conclusions: Hudson prong bubble continuous positive airway pressure therapy reduces the need for up-transfer of infants with respiratory distress in non-tertiary centers. There is a clinically relevant but not statistically significant increase in the risk of pneumothorax. There are significant benefits associated with continuous positive airway pressure use in larger non-tertiary centers.
4. Brain haemodynamic effects of nasal continuous airway pressure in preterm infants of less than 30 weeks� gestation
Dani C, Bertini G, Cecchi A, Corsini I, Pratesi S, Rubaltelli FF
Acta Paediatr 2007;96:1421-5.
Aim: To evaluate the hypothesis that increasing levels of nasal continuous positive airway pressure (NCPAP) may decrease cerebral blood volume (CBV) and cerebral oxygenation in infants with gestational age (GA) less than 30 weeks.
Methods: We prospectively studied a cohort of preterm infants treated with NCPAP using near-infrared spectroscopy (NIRS). The pressure limit of NCPAP was set at 2, 4, 6 and again 2 cm H2O for 30 min.
Results: Changes of pressure levels were not followed by significant changes of oxygenated haemoglobin (O2Hb), deoxygenated haemoglobin (HHb), cerebral intravascular oxygenation (HbD), oxidized-reduced cytochrome aa3 (CtOx), tissue oxygenation index (TOI), tissue haemoglobin index (THI) and cerebral blood volume (CBV).
Conclusion: NCPAP at 2-6 cm H2O pressure levels did not affect cerebral oxygenation and CBV. These findings are reassuring and confirm the safety of NCPAP in preterm infants with GA less than 30 weeks.
Read 'CPAP - A Gentler Mode of Ventilation' in Journal of Neonatology, 2007 (a review article by Dr. Jeevasankar M and Dr Ashok Deorari).