Acid-base balance.
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Acid-Base Equilibrium↗
Biomedical subjects
M Gårdebäck
Publications and source records attributed to M Gårdebäck.
Hepatic blood flow and right ventricular function during cardiac surgery assessed by transesophageal echocardiography.
OBJECTIVE: To determine the effect of cardiopulmonary bypass (CPB) on hepatic blood flow (HBF) and the hepatic venous flow pattern. DESIGN: Single-arm prospective study. SETTING: University hospital operating room and intensive care unit. PARTICIPANTS: Eight patients ranging in age from 57 to 73 years undergoing cardiac surgery. INTERVENTIONS: Transesophageal echocardiography (TEE) was used to assess HBF before, during, and after CPB by pulsed-wave Doppler ultrasound recordings of hepatic venous flow velocity and two-dimensional recordings of the hepatic vein diameter. Hepatic vein oxygenation was monitored by hepatic vein catheterization, and gastric intramucosal pH (pHi) was followed by tonometry. MEASUREMENTS AND MAIN RESULTS: The HBF was unchanged after the start of CPB but was reduced from the baseline value 415 (standard error of the mean 40) mL/min to 225 (25) mL/min during hypothermic CPB (p < 0.05). Cardiac index, right ventricular ejection fraction, and arterial and tonometric pH were essentially unchanged during the study period. Hepatic vein and mixed venous saturation were unchanged compared to control during CPB and were reduced at 2 and 3 hours after CPB (p < 0.01). Six of the patients had a normal predominant systolic flow pattern before surgery. In the postoperative period, seven patients showed an abnormal predominant diastolic filling pattern. CONCLUSIONS: TEE represents a useful tool in assessing changes in the hepatic blood flow. The HBF was reduced during hypothermic CPB, but this was not accompanied by a reduced pHi. The changes in the venous flow pattern with a reduction in systolic flow could be explained by impaired atrial relaxation.
Aged↗
Nitric oxide improves hypoxaemia following reperfusion oedema after pulmonary thromboendarterectomy.
A patient underwent pulmonary thromboendoarterectomy for chronic, major-vessel thromboembolic pulmonary hypertension. After operation the patient developed reperfusion oedema and hypoxaemia which was treated successfully with inhalation of nitric oxide. Before operation, the response to inhaled nitric oxide was characterized by a slight reduction in pulmonary vascular resistance but without improvement in gas exchange. The postoperative improvement in oxygenation after inhalation of nitric oxide contrasted sharply with the preoperative reaction.
Endarterectomy↗
Effect of dopexamine on calculated low gastric intramucosal pH following valve replacement.
Gastric tonometry was used to study the possible effect of dopexamine infusion on a low calculated intramucosal pH (pHi) as a sign of splanchnic ischemia. Measurements were made during surgery and for approximately 18 hours postoperatively on 19 non-selected adult patients undergoing valve replacement. Patients developing a postoperative pHi > 7.30 were randomized to receive dopexamine (2 micrograms.kg-1 min-1) or placebo in a double blind fashion. Eighteen patients were randomized, 10 to receive dopexamine and 8 to placebo. The calculated pHi remained unchanged for the first 2 hours in both groups. After 4 hours a significant (P < 0.05) decrease in pHi was noted in the dopexamine group which remained significantly below the placebo group during the monitoring period. The dopexamine treated patients had a significantly longer period of low pHi but the pH-gap i.e. the difference between arterial pH and pHi did not differ between the two groups. Patients with postoperative complications, defined as infections (2), myocardial infarction (1), single- (2) or multiple organ failure and death (1), did not have longer periods with pHi below 7.30. In these patients, however, a pH-gap > 0.12 occurred more often than in those without complications, indicating that an increased incidence of complications was related to a pH-gap > 0.12. It is our opinion that true mucosal ischemia is best detected by estimating the difference in carbon dioxide tension between arterial blood and mucosa. This can be expressed either directly as PCO2-gap (PtonCO2-PaCO2) or indirectly as pH-gap.
Adrenergic beta-Agonists↗
Dopexamine and dopamine in the prevention of low gastric mucosal pH following cardiopulmonary by-pass.
The effect of low-dose dopexamine and dopamine on gastric intramucosal pH (pHi) during cardiac surgery and 16 hours postoperatively was studied in 35 adults patients (coronary artery bypass grafting and/or valve replacement). The patients were assigned randomly to treatment groups with either dopexamine (1 microgram.kg-1.min-1 (n = 12), dopamine 2.5 micrograms.kg-1.min-1 (n = 11) or to a control group (n = 12). The infusions were started after induction of anaesthesia and were continued until 16 hours after CPB. pHi and arterial pH (pHa) did not differ between groups and remained unchanged during cardiopulmonary by-pass and for the first four postoperative hours. Both the carbon dioxide tension of arterial blood (PaCO2) and of the saline in the tonometer (PtonCO2) changed in parallel with a decrease during CPB and an increase after CPB and surgery with maximal values 12 hours after termination of CPB. A significant correlation was noted between pHi and pHa and between arterial and tonometric PCO2. It is concluded that low dose dopexamine and dopamine have no influence on pHi during and after cardiac surgery. The observed changes in pHi and PtonCO2 were due to changes in pHa and in PaCO2 and not a sign of gastric mucosal ischemia.
Adrenergic beta-Agonists↗