title: The effect of PVC packaging on the acidity of 0.9% saline.
abstract: Intravenous fluids in polyvinyl chloride (PVC) packaging are known to be acidic. We proposed to determine the effect of PVC packaging on the pH of 0.9% saline solutions by comparing the predicted and measured pH of 0.9% saline equilibrated with atmospheric carbon dioxide and the measured pH of commercial solutions of 0.9% saline in PVC and polypropylene packaging. Calculation of pH was made from available physical chemistry constants and data. Measurement was made of the pH of 12 samples of prepared 0.9% saline equilibrated with atmospheric carbon dioxide. Comparison with the pH of seven commercial samples of saline in PVC packaging for intravenous use was undertaken. Further comparison was made between commercial samples of 0.9% saline in PVC or polypropylene packaging. The calculated pH of 0.9% saline was 5.61 at 20 degrees C. The median pH of the prepared samples was statistically significantly less acidic than the median pH of the PVC packaged samples for intravenous use: 5.47 vs 4.60, P < 0.05. The median pH of the PVC packaged saline was also statistically significantly more acidic than the pH of the polypropylene packaged saline: 4.62 vs 5.71, P < 0.05. The acidity of the intravenous solutions of 0.9% saline packaged in PVC was much greater than expected and is only partially explained by dissolved carbon dioxide. This acidity could be a result of packaging in PVC.
authors.affiliation: Physical Chemistry Laboratory, School of Chemistry, University of Melbourne, Victoria.
authors.forename: D A
authors.initials: DA
authors.lastname: Story
authors.forename: P
authors.initials: P
authors.lastname: Thistlethwaite
authors.forename: R
authors.initials: R
authors.lastname: Bellomo
mesh_terms: D000143:Acids / Q000737:chemistry; D001639:Bicarbonates / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002255:Carbonic Acid / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D016001:Confidence Intervals; D004340:Drug Contamination; D004349:Drug Packaging; D005440:Fluid Therapy / Q000295:instrumentation; D005544:Forecasting; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007275:Injections, Intravenous; D011126:Polypropylenes / Q000737:chemistry; D011143:Polyvinyl Chloride / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000143:Acids; D001639:Bicarbonates; D011126:Polypropylenes; D014867:Water; D002245:Carbon Dioxide; D012965:Sodium Chloride; D002255:Carbonic Acid; D011143:Polyvinyl Chloride