Open AccessThe Precision of a Special Purpose Analog Computer in Clinical Cardiac Output Determination
Author(s) -
Francis Sullivan,
Edmund A. Mroz,
Robert E. Miller
Publication year - 1975
Publication title -
annals of surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.153
H-Index - 309
eISSN - 1528-1140
pISSN - 0003-4932
DOI - 10.1097/00000658-197502000-00019
Subject(s) - medicine , calibration , calibration curve , analog computer , cardiac output , value (mathematics) , statistics , cardiology , mathematics , electrical engineering , detection limit , engineering , hemodynamics
Three hundred dye-dilution curves taken during our first year of clinical experience with the Waters CO-4 cardiac output computer were analyzed to estimate the errors involved in its use. Provided that calibration is accurate and 5.0 mg of dye are injected for each curve, then the percentage standard deviation of measurement using this computer is about 8.7%. Included in this are the errors inherent in the computer, errors due to baseline drift, errors in the injection of dye and acutal variation of cardiac output over a series of successive determinations. The size of this error is comparable to that involved in manual calculation. The mean value of five successive curves will be within 10% of the real value in 99 cases out of 100. Advances in methodology and equipment are discussed which make calibration simpler and more accurate, and which should also improve the quality of computer determination. A list of suggestions is given to minimize the errors involved in the clinical use of this equipment.