Right Ventricular Dysfunction and Dilatation, Similar to Left Ventricular Changes: METHODS

9 Mar
2011

Patient Population

Thirty nine patients with septic shock were studied in the Medical Intensive Care Unit at the Clinical Center of the National Institutes of Health, Bethesda, Md. All patients met our clinical definition of septic shock: fever (temperature >38°C), hypotension (mean arterial pressure <60 mm Hg), and positive blood cultures. The mean age of the patients was 45.2 years, with a range of 12 to 73 years. There were 23 male and 16 female patients. Twenty-two patients (56 percent) survived the acute septic shock episode; 17 did not. Underlying diseases included malignant neoplasms in 35 patients and one patient each with chronic hepatitis, Cushing’s syndrome, a-antitrypsin deficiency, and an immunodeficiency of undetermined cause. Sixteen patients had Cram-negative organisms in their blood, 12 had Cram-positive organisms, five had a fungus, and six had mixed infections with more than one organism cultured (two with a Cram-positive organism and fungus; one with a Cram- negative organism and a fungus; one with a Cram-positive and a Gram-negative organism; one with two different Gram-negative organisms; and one with a Gram-positive organism, a Gram-negative organism, and a fungus).

Eight of 17 nonsurvivors were mechanically ventilated at the time of the initial study, six of these with the use of positive end- expiratory pressure (mean 7.8 ±1.6 cm HaO). An additional three nonsurvivors required mechanical ventilation at the time of the final study. Four of 22 survivors were mechanically ventilated at the time of the initial study with a mean of 7.0 ± 1.7 cm H20 of positive end- expiratory pressure.

Therapeutic Protocol

All patients were treated by one group of critical care physicians employing a standard sequential therapeutic protocol for the management of septic shock-associated hypotension. Initially, fluids were administered intravenously to maintain the pulmonary artery wedge pressure at 15 to 18 mm Hg. Patients remaining hypotensive (mean arterial pressure <60 mm Hg) were given dopamine hydro­chloride titrated to a maximum dose of 20 jjig/kg/min. If hypotension persisted, intravenous levarterenol was added and titrated to maintain a mean arterial pressure of at least 60 mm Hg, and dopamine hydrochloride was decreased to 2 м-g/kg/min in an attempt to preserve renal perfusion. canadian pharmacy generic viagra

Nine of 22 survivors were receiving vasopressors on the initial study. None required vasopressor support at the time of the final study. Nine of 17 nonsurvivors required vasopressors at the time of the initial study. Fifteen of 17 were receiving vasopressor support during the final study.

Hemodynamic Measurements

All patients were treated with an indwelling arterial catheter and a balloon-tipped pulmonary artery catheter. Serial hemodynamic measurements were performed at least daily, including heart rate, mean arterial pressure, central venous pressure, pulmonary artery pressure, pulmonary artery wedge pressure, and thermodilution cardiac output. Pulmonary artery wedge pressure was determined from paper tracings on a strip chart recorder at end expiration. Using 10 ml of 5 percent dextrose in water, three to five consecutive measurements of cardiac output using the thermodilution technique were performed. The cardiac output recorded was the mean of either the three cardiac output values that varied by less than 10 percent, or the mean of the three closest determinations (of five) after elimination of high and low values.


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