title: Effects of flow rate on delivery of bubble continuous positive airway pressure in an in vitro model.
abstract: BACKGROUND
  There has been concern over the effect of vigorous bubbling on the delivery pressure during the operation of the bubble nasal continuous positive airway pressure (CPAP) system. We investigated the relationship between intra-tubing pressure changes and flow rates in a closed bubble CPAP system in vitro.
  
  
  METHODS
  Using an experimental (in vitro) model, the distal connecting tube of the CPAP system was immersed under the water seal to a depth of 5 cm. Sixteen different flow rates, ranging from 2 L/min to 20 L/min, were tested. The procedure was repeated 10 times at each flow rate, and the intra-tubing pressure was recorded.
  
  
  RESULTS
  The intra-tubing pressure within the model increased as the air flow rates were adjusted from 2 L/min to 20 L/min. The relationship was represented by the following equation, pressure (cmH(2)O) = 5.37 + 0.15 x flow rate (L/min) (R(2) = 0.826, p < 0.001).
  
  
  CONCLUSIONS
  These results demonstrated that the intra-tubing pressure in a bubble CPAP system was highly correlated with flow rate in vitro.
authors: Division of Pediatrics, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan. Electronic address: treeho@yahoo.com.tw.
authors: Tsyr-Yuh
authors: TY
authors: Ho
authors: Division of Pediatrics, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan.
authors: Shan-Fu
authors: SF
authors: Ou
authors: Department of Nursing, Fooying University, Kaohsiung County, Taiwan.
authors: Shih-Hui
authors: SH
authors: Huang
authors: Division of Pediatrics, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan.
authors: Chi-Ning
authors: CN
authors: Lee
authors: Department of Pediatrics and Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, National Yang-Ming University, Taipei, Taiwan.
authors: Luo-Ping
authors: LP
authors: Ger
authors: Department of Pediatrics and Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, National Yang-Ming University, Taipei, Taiwan.
authors: Kai-Sheng
authors: KS
authors: Hsieh
authors: Department of Nursing, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan.
authors: Hui-Ying
authors: HY
authors: Cheng
authors: Department of Pediatrics, Kaohsiung Municipal United Hospital, Kaohsiung, Taiwan.
authors: Wei Yang
authors: WY
authors: Lee
authors: Division of Pediatrics, Zuoying Armed Forces General Hospital, Kaohsiung, Taiwan; Department of Nursing, Fooying University, Kaohsiung County, Taiwan; Department of Pediatrics and Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, National Yang-Ming University, Taipei, Taiwan; Yuh-Ing Junior College of Health Care and Management, Kaohsiung, Taiwan. Electronic address: kenpenweng@yahoo.com.tw.
authors: Ken-Pen
authors: KP
authors: Weng
mesh_terms: D000399:Air Pressure; D000403:Airway Resistance / Q000502:physiology*; D045422:Continuous Positive Airway Pressure / Q000295:instrumentation*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007440:Intubation / Q000295:instrumentation*; D008954:Models, Biological; D012127:Respiratory Distress Syndrome, Newborn / Q000628:therapy*; D012212:Rheology