ABSTRACT
Changes in systemic oxygen delivery after acute myocardial infarction were investigated in 21 patients. In seven patients with shock, circulatory failure was characterized by a significant reduction in cardiac index, a decrease in oxygen transport and oxygen consumption and an increase in concentration of blood lactate; a decrease in the affinity of hemoglobin for oxygen (increased P50) was also noted. The P50 averaged 28.8 plus or minus 0.87 (standard error of the mean) torr in patients with shock and 26.0 plus or minus 0.45 torr (P less than 0.05) in patients without circulatory failure. However, there was no significant difference in oxygen extraction from arterial blood between the two groups. The time course of the changes in P50, cardiac index and oxygen consumption was separately examined in 12 patients. In six patients with shock, P50 increased by an average of 4.6 plus or minus 2.05 torr (P less than 0.05) and this augmentation accounted for an estimated 18 percent increase in oxygen release. Maximal P50 values were observed after 24 hours of circulatory failure. In the absence of shock, no consistent changes in P50, cardiac index or oxygen consumption were observed. These data indicate that a reduction in oxygen delivery after acute myocardial infarction is followed by a compensatory increase in P50. This change in P50 accounts for increases in oxygen availability independently of changes in cardiac output.
Subject(s)
Hemoglobins/metabolism , Myocardial Infarction/metabolism , Oxygen Consumption , Oxyhemoglobins/metabolism , Shock, Cardiogenic/metabolism , Aged , Cardiac Output , Female , Hemodynamics , Humans , Male , Middle Aged , Myocardial Infarction/blood , Partial Pressure , Shock, Cardiogenic/bloodABSTRACT
A circuit for selective ventilation distribution (S.V.D.C.) is described. The use of the circuit is illustrated with five cases in which it was used. S.V.D.C. allowed: 1) Measurement of individual lung tidal volumes and pressures during the respiratory cycle. 2) Adjustment of the tidal volumes of both lungs in the most appropriate way for the patient. 3) Application of different degrees of PEEP to each lung. The circuit is easily built and managed, the patient is connected to it by a double lumen endotracheal tube (Carlens tube); the circuit requires only one respirator.
Subject(s)
Respiration, Artificial/instrumentation , Respiratory Insufficiency/therapy , Adult , Aged , Female , Humans , Male , Middle Aged , Oxygen Inhalation Therapy , Positive-Pressure RespirationABSTRACT
OBJECTIVE: To compare changes in the health-related quality of life (HRQOL) of critical care patients by diagnostic category. DESIGN: Prospective, cohort study. HRQOL assessed 3 months before admission and 1 year after discharge from the intensive care unit (ICU). Patients were classified as: trauma injury (TI), scheduled surgery (SS), unscheduled surgery (US), and other medical conditions (MC). SETTING: Department of Intensive Medicine, University Hospital of Bellvitge, Barcelona, Spain. PATIENTS: Three hundred and thirty-four patients admitted to ICU from October 1994 to June 1995 (62 TI patients, 181 SS patients, 19 US patients, and 72 MC patients). INTERVENTIONS: Surgical and medical procedures. MEASUREMENTS AND RESULTS: Changes in HRQOL varied considerably between diagnostic categories, with TI patients having significantly worse HRQOL one year after discharge from the ICU compared to 3 months prior to admission [change in median EQ Visual Analogue Scale (EQ-VAS) score from 100 to 65, P<0.001], and SS patients reporting improved HRQOL (change in median EQ-VAS scores from 60 to 75, P<0.001). Slight deterioration was observed in the other two diagnostic categories. Twelve months after discharge, the EQ dimension in which the largest proportion of patients in all groups reported problems was usual activities (47% of SS and US patients; 69% of TI patients). Using proxy scores at baseline or follow-up had little effect on results. CONCLUSIONS: The degree and direction of change in ICU patients' HRQOL 1 year after discharge depends considerably on diagnostic category. Proxy responses can be reliably used with the EQ-5D when measuring change in HRQOL.
Subject(s)
Intensive Care Units , Outcome Assessment, Health Care , Quality of Life , Sickness Impact Profile , Adult , Aged , Analysis of Variance , Diagnosis-Related Groups , Europe , Female , Humans , Male , Middle Aged , Prospective Studies , Spain , Statistics, NonparametricSubject(s)
Abortion, Therapeutic/adverse effects , Hypertonic Solutions/adverse effects , Adolescent , Blood Urea Nitrogen , Carbon Dioxide/blood , Chlorides , Creatine/urine , Female , Heart Failure/chemically induced , Humans , Hydrogen-Ion Concentration , Hypertonic Solutions/administration & dosage , Lactates/metabolism , Neurologic Manifestations , Osmolar Concentration , Oxygen/blood , Peritoneal Dialysis , Pregnancy , Pulmonary Edema/chemically induced , Sodium/metabolism , Sodium Chloride/administration & dosage , Sodium Chloride/adverse effects , Time Factors , Water-Electrolyte BalanceABSTRACT
P50 was calculated from a single measurement of pH, Po2, and So2 at a known temperature in 135 blood samples from 21 normal nonsmokers and eight patients. In the 92 blood samples with So2 between 20 and 90 per cent, the standard deviation of repeated calculated P50's on the same sample of blood at different So2 was plus or minus 1.0 Torr. Below So2 of 20 per cent and above So2 of 90 per cent, the standard deviations were plus or minus 5.5 and plus or minus 2.4 Torr, respectively. Combined measurement errors of plus or minus 1 Torr in Po2, plus or minus 1 percent in So2, plus or minus 0.01 in pH, and plus or minus 0.1 degree C in temperature are sufficient to explain the observed variation in calculated P50 in 90 per cent of 135 blood samples from 29 subjects and account for the greater observed variation at So2 less than 20 per cent and greater than 90 per cent.
Subject(s)
Hemoglobins , Oxygen/blood , Carbon Dioxide/blood , Carboxyhemoglobin/analysis , Humans , Hydrogen-Ion Concentration , Methods , Partial Pressure , Temperature , Tonometry, OcularABSTRACT
We studied in vitro changes in P50 and erythrocyte 2,3-diphosphoglycerate concentration occurring in blood 2 to 8 h after venipuncture. When blood was incubated at 37 degrees C, significant decreases in P50 were observed at 2, 4, and 8 hr. Such a change was significantly less when blood was kept at 4 degrees C. The rate of decrease in P50 was not changed when pH was altered by adding either lactic acid or sodium bicarbonate to the blood before incubation at 37 degrees C for 2 h. The erythrocyte 2,3-diphosphoglycerate concentration of blood incubated at 37 degrees C did not change by 2 h, but had significantly decreased by 4 h. To avoid in vitro changes, we recommend that P50 be determined as soon as possible for blood sampling.
Subject(s)
Diphosphoglyceric Acids/blood , Erythrocytes/metabolism , Oxygen/blood , Carbon Dioxide/blood , Carboxyhemoglobin/analysis , Humans , Hydrogen-Ion Concentration , Oxyhemoglobins/analysis , Partial Pressure , TemperatureABSTRACT
A description of a selective ventilation distribution circuit (S.V.D.C.). The use of this circuit is illustrated by the description of 5 cases where the following were applied: 1 - the measurement of tidal volume of pressures for each lung during the respiratory cycle; 2 - regulation of tidal volumes to be as appropriate as possible for the patient; 3 - the application of different degrees of PEEP for each lung. This circuit is easy to construct and manipulate. It is connected to the patient via a double lumen endotracheal tube (Carlens) and uses only one respiratory.