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Biomedical subjects

J Heinonen

Publications and source records attributed to J Heinonen.

At least 55 records · Page 3Linked to original sources
PubMed1987

Plasma atrial natriuretic peptide concentrations during induction of anesthesia and acute volume loading in patients undergoing cardiac surgery.

Induction of anesthesia with fentanyl for coronary artery bypass grafting decreased (P less than .05) plasma atrial natriuretic peptide (ANP) concentrations from awake values in twelve patients. During a steady state of anesthesia before surgery, isotonic saline solution (10 mL/kg) was infused simultaneously with the elevation of the lower extremities in six patients, while six subjects served as controls receiving no volume loading and having no leg raising. The ANP levels returned to the awake values in the volume-loaded patients, while plasma ANP remained at anesthetized baseline levels in the control subjects (P less than .01 between the groups). Ten minutes after the end of the loading procedure, plasma ANP had begun to decrease again towards the postinduction level in the loaded group, but a significant (P less than .05) difference was still observed between the groups. These changes in ANP levels paralleled those of cardiac filling pressures. In conclusion, the results suggest that the degree of distention of the atria regulates the secretion of atrial natriuretic peptide into the circulation in patients anesthetized with fentanyl.

Anesthesia, Intravenous↗
PubMed1986

Contribution of muscle relaxant to the haemodynamic course of high-dose fentanyl anaesthesia: a comparison of pancuronium, vecuronium and atracurium.

To define the role of muscle relaxants in haemodynamic responses to high-dose (75 micrograms X kg-1) fentanyl anaesthesia and to noxius stimuli associated with intubation and sternal spread during coronary artery bypass surgery, we compared haemodynamics between three groups of patients given either pancuronium (0.1 mg X kg-1, n = 11), vecuronium (0.086 mg X kg-1, n = 11) or atracurium (0.43 mg X kg-1, n = 12). Additional doses of the relaxants were given to maintain a 90 per cent neuromuscular block. Patients given pancuronium showed no increases in mean values of heart rate, arterial pressure or cardiac output during the induction of anaesthesia or after intubation, whereas a decrease in these variables was observed in the vecuronium group. The haemodynamics in the atracurium group were intermediate compared with the other two study groups. In spite of a decrease in coronary perfusion pressure, no patient given vecuronium developed myocardial ischaemia. An advantage of vecuronium over pancuronium and atracurium was an attenuation of the blood pressure response to sternotomy. Patients given atracurium had a small increase in pulmonary vascular resistance during sternotomy. Our patients continued their beta-adrenergic antagonist medication until the morning of the day of operation and they were pretreated with a small intravenous dose of diazepam (0.1 mg X kg-1) before induction of anaesthesia. These drugs may have prevented the deleterious haemodynamic effects observed by some investigators after the administration of pancuronium during high-dose fentanyl anaesthesia.

Adult↗
PubMed1986

Continuous infusion of fentanyl or alfentanil for coronary artery surgery. Plasma opiate concentrations, haemodynamics and postoperative course.

Nine patients received a mean total dose of 110 micrograms kg-1 of fentanyl and 10 patients received alfentanil 1379 micrograms kg-1 as a continuous infusion during coronary artery bypass grafting (CABG). Circulatory stability was well maintained through the induction of anaesthesia and a similar cardiovascular course was achieved with both agents, with the exception of small differences in heart rate and cardiac index immediately before tracheal intubation. Similar haemodynamic responses to sternotomy, cardiopulmonary bypass and awakening from anaesthesia were found with both analgesics. Although the times to awakening and extubation were somewhat shorter in patients receiving alfentanil, the differences between the groups were not significant. With the continuous infusion techniques, plasma opiate concentrations could be maintained well above the awakening values during cardiopulmonary bypass. In a total dose ratio of 1:13, fentanyl and alfentanil produced similar haemodynamic profiles and clinical courses in patients undergoing CABG.

Adult↗
PubMed1986

Continuous infusion of fentanyl or alfentanil for coronary artery surgery. Effects on plasma cortisol concentration, beta-endorphin immunoreactivity and arginine vasopressin.

Plasma cortisol, beta-endorphin immunoreactivity (PBEir) and arginine vasopressin (AVP) responses during and after the continuous infusion of fentanyl or alfentanil were studied in 19 patients undergoing coronary artery bypass grafting (CABG). Plasma cortisol concentration decreased significantly in both groups during the anaesthesia and surgery before cardiopulmonary bypass (CPB); an increase was evident during CPB in both groups, but a statistically significant increase was not observed during the rest of the study, including the awakening from anaesthesia. PBEir increased with both opiates immediately after initiation of CPB and remained so during the rest of the study. There were no significant changes in plasma AVP concentrations during anaesthesia and surgery. After discontinuation of opiate infusions, an increase in AVP concentration commenced earlier in the alfentanil group than in the fentanyl group. At awakening from anaesthesia, a significant correlation was observed between log plasma AVP concentration and systemic vascular resistance. It is concluded that, with continuous fentanyl and alfentanil infusions in a total dose relationship of 1:13 in patients undergoing CABG, cortisol and AVP responses to surgery and CPB can be suppressed. However, during recovery from anaesthesia, the attenuating effect of alfentanil seems to wear off more rapidly than that of fentanyl. PBEir response to CPB and emergence from anaesthesia could not be prevented with either analgesic.

Adult↗
PubMed1986

Pulmonary vascular responses to moderate changes in PaCO2 after cardiopulmonary bypass.

Clinical observation by the authors suggests that small changes in PaCO2 cause significant alterations in pulmonary hemodynamics after cardiac surgery. To examine this, the authors induced moderate ventilatory hypocarbia (PaCO2 = 30.7 +/- 0.4 mmHg, mean +/- SD) in eight patients early after coronary artery bypass surgery. Normocarbia (40.6 +/- 0.5 mmHg) and hypercarbia (51.5 +/- 0.5 mmHg) were then induced by adding CO2 to the inspired gas. Standard hemodynamic measurements were performed at each stage. In four of the patients, CO2 exposure was subsequently withdrawn in reversed order. There were no clinically significant changes in systemic hemodynamics. Despite unchanged pulmonary blood flow, in all patients pulmonary artery pressure increased with increasing PaCO2. An almost two-fold and three-fold increase was observed in the mean pulmonary vascular resistance (PVR) and pulmonary diastolic gradient (pulmonary artery diastolic pressure-pulmonary capillary wedge pressure), respectively, when PaCO2 was changed from hypocarbia to hypercarbia. The changes in the pulmonary diastolic gradient correlated (r = 0.77, P less than 0.001) with the changes in the PVR. The pulmonary vasoconstrictor response was reversible with CO2 washout. Avoidance of even moderate hypercarbia, therefore, seems advisable in the early postperfusion stage because of a further potential impedance to right ventricular ejection. Frequent measurement of pulmonary diastolic pressure gradient provides a useful method of rapid estimation of the resistance to flow in the pulmonary vascular bed.

Adult↗
PubMed1985

Increased pulmonary artery diastolic-pulmonary wedge pressure gradient after cardiopulmonary bypass.

In 29 patients undergoing elective coronary artery bypass grafting, the diastolic pulmonary arterial pressure-pulmonary capillary wedge pressure gradient (DPAP-PCWP) and related haemodynamic parameters were determined before and after induction of anaesthesia, immediately after cardiopulmonary bypass (CPB) and one and three hours after CPB. The DPAP-PCWP gradient remained unchanged after induction of anaesthesia but was significantly increased after CPB. A gradient of 5 mmHg or greater was observed in 16 patients after CPB, whereas none of the patients showed such a gradient before CPB. A significant correlation was found between the change in DPAP-PCWP and the change in pulmonary vascular resistance (PVR). It is concluded that DPAP should not be used as a substitute of PCWP in the early postbypass period without frequent confirmation of the presence of the normal small DPAP-PCWP gradient. Since an increase of PVR may impair right ventricular ejection, we recommend the routine measurement of DPAP-PCWP gradient in the postbypass period.

Anesthesia, General↗
PubMed1985

Comparison of Ringer's acetate and lactate solutions as a prime for cardiopulmonary bypass.

Nineteen patients undergoing myocardial revascularization were randomly given either Ringer's lactate or acetate solution as the prime of cardiopulmonary bypass (CPB), and systemic vascular resistance (SVR) was determined before, and for 10 minutes after, the commencement of CPB. There were no significant differences in SVR or perfusion pressure between the acetate or lactate groups before or during CPB. Blood gas and acid-base values, haematocrit, serum potassium, sodium and ionized calcium concentrations as well as patient temperature were similar in the two study groups. Our results are at variance with some previous experimental findings, which have suggested that acetate has a greater vasodilative effect than lactate.

Acetates↗
PubMed1984

Transcutaneous oxygen measurement during one-lung anaesthesia.

The value of continuous transcutaneous oxygen tension (Ptco2) monitoring was assessed during the rapidly changing conditions of oxygenation associated with the commencement of one-lung ventilation (OLV) during thoracic surgery. In ten patients anaesthetized with enflurane-N2O (Fio2 0.5), Pao2, Ptco2, cardiac output and arterial pressure were measured first during two-lung ventilation (TLV) and thereafter at frequent intervals during OLV. These variables remained stable during TLV. The mean Pao2 dropped from 24.9 kPa to 11.4 kPa during the first 10 min of OLV. The accompanying decrease in Ptco2 was slower, the mean Ptco2 being 1.3-2.1 kPa higher than Pao2. Ptco2 correlated well with Pao2 during OLV (r = 0.907). The elevated Ptco2 index (Ptco2/Pao2) may be partly due to the delayed response of the Ptco2-detection system in vivo. It is concluded that transcutaneous oxygen monitoring may be used to assess oxygenation in those cases where arterial cannulation is not feasible or if the laboratory conditions cause an undue delay between blood sampling and obtaining the blood-gas data.

Anesthesia, Inhalation↗
PubMed1984

Atropine vs glycopyrrolate during reversal of pancuronium block in patients anaesthetized with halothane.

Atropine 0.015 mg kg-1 and glycopyrrolate 0.0075 mg kg-1 were compared as antimuscarinic agents during reversal of pancuronium block with neostigmine 0.03 mg kg-1 in 30 patients anaesthetized with thiopental-N2O-halothane and undergoing minor surgery. In patients treated with atropine-neostigmine, the frequencies of bradycardia and junctional rhythm were relatively high and about the same as those reported by us previously in patients anaesthetized with thiopental-N2O-fentanyl. As in our previous study, glycopyrrolate seemed to have advantages over atropine during reversal of pancuronium block: the incidences of bradycardia and junctional rhythm were significantly less in patients treated with glycopyrrolate. Recovery from anaesthesia, as assessed by the awakening after discontinuation of N2O and halothane administration, and the incidence of postoperative nausea and vomiting, were not significantly different between the atropine and glycopyrrolate groups.

Adult↗
PubMed1983

A new sensitive, thiol tolerant method for the determination of inorganic pyrophosphatase.

In this work a new sensitive, thiol tolerant method for the determination of inorganic pyrophosphatase (EC 3.6.1.1) was developed. It is based on the formation of phosphomolybdate-triethylamine complex, which in acid-acetone mixture forms a white, homogeneous precipitate, the turbidity of which can accurately measured spectrophotometrically at 355 nm. This method can be easily applied to all the Pi-producing enzymes whose substrates are stable enough in our acidic experimental conditions.

Drug Stability↗
PubMed1983

Cardiovascular effects of pancuronium and vecuronium during high-dose fentanyl anesthesia.

To define the role of muscle relaxants in hemodynamic responses to high-dose (75 micrograms/kg) fentanyl anesthesia, we compared the circulatory effects of pancuronium (Pc) with those of vecuronium (Vc) in patients about to undergo coronary artery bypass surgery. The first measurements were made while the patients were awake. Thereafter the patients were anesthetized with fentanyl, intubated under succinylcholine relaxation and mechanically ventilated with a mixture of oxygen in air (FIO2 0.50). Ten minutes after completion of the fentanyl injection, the second set of measurements was made. Immediately thereafter, 0.1 mg/kg of either Pc (n = 10) or Vc (n = 10) was given, and no relaxant was administered to 10 control patients. Heart rate (HR) and cardiac index (CI), which had decreased significantly after fentanyl induction, decreased further after Vc, the latter decreases being significantly greater than the decreases in HR and CI observed in control patients. After Pc, HR and CI increased to control awake levels; rate-pressure product also increased and stroke index decreased. Five of ten patients receiving Vc had a HR below 45 beats/min; HRs this low were not seen in patients given Pc. Neither Pc nor Vc affected systemic vascular resistance, but filling pressures of the heart decreased abruptly after both relaxants. We conclude that if maintenance of preanesthetic hemodynamic status is the objective of anesthetic management of patients having coronary artery bypass surgery, Pc helps to achieve this objective during high-dose fentanyl anesthesia. On the other hand, many patients with limited coronary vascular reserve may well benefit from the negative chronotropic effect of Vc.

Anesthesia, Intravenous↗
PubMed1983

Hydroxyurea inhibits also the syntheses of thymine nucleotides and methionine in the cells of Escherichia coli.

Hydroxyurea not only inhibited the reduction of ribonucleotides, but also gave rise to need of exogenous methionine and thymidine for full growth in the cultures of Escherichia coli K12. In vitro the drug inhibited the formation of 5,10-methylenetetrahydrofolate by serine hydroxymethyltransferase in the cell extracts, which suggests that this reaction is a secondary target of hydroxyurea in the cells of E. coli. The syntheses of thymine nucleotides and methionine were also the most sensitive targets of hydroxylamine in the cultures of E. coli.

Escherichia coli↗
PubMed1982

Nonspecificity of some commonly used inhibitors of DNA synthesis in cultures of Streptococcus faecalis.

The specificity of three commonly used inhibitors of DNA synthesis were tested in the batch culture of Streptococcus faecalis ATCC 8043 in rich broth medium. It was shown that nalidixic acid, mitomycin C and 6-(4-hydroxyphenylazo)uracil inhibit the growth of the cell mass as much as they decrease net DNA synthesis. Hence the drugs tested are highly unspecific inhibitors of DNA synthesis in S. faecalis; i.e. they all interfere with other processes as well as with DNA synthesis.

DNA Polymerase III↗
PubMed1982

Correlation of hypotensive effect of plasma protein fraction with prekallikrein activator activity: a clinical study in patients having open-heart surgery.

We studied the hemodynamic responses to the administration of 20 ml of three protein solutions having different prekallikrein activator (PKA) activities in patients undergoing cardiac operation. PKA levels of the two plasma protein fraction (PPF) solutions studied were 193% and 60%, respectively, while that of the albumin solution was less than or equal to 3%. A significant correlation was found between the PKA activity of the test solutions and the decrease in systemic vascular resistance produced by the solutions during cardiopulmonary bypass and in the postoperative period. Vasodilatation was considerably more marked in the postoperative phase than during cardiopulmonary bypass. Since cardiac output increased simultaneously with the decrease in vascular resistance in the postoperative period, the hypotension observed did not fully reflect the degree of vasodilatation. In some patients, substantial vasodilatation was observed also after the administration of albumin solution with low PKA level. We conclude that although the PPF-induced vasodilatation correlates with the PKA activity of the solution, occasional hypotensive reactions are probably due to mechanisms other than those linked with increased PKA level.

Adult↗
PubMed1982

Advantages of glycopyrrolate over atropine during reversal of pancuronium block.

Atropine 0.015 mg kg-1 and glycopyrrolate 0.0075 mg kg-1 were compared as antimuscarinic agents during reversal of pancuronium block with neostigmine 0.03 mg kg-1 in 30 patients anaesthetized with thiopental - N2O- fentanyl and undergoing minor surgery. The decrease of heart rate was more pronounced in patients who received atropine-neostigmine. The mean of the lowest heart rate was 44.3 beats min-1 in the atropine group compared with 54.3 beats min-1 in the glycopyrrolate group. Five patients with atropine-neostigmine developed a transient nodal rhythm as compared with two of those receiving glycopyrrole-neostigmine (non-significant difference). Recovery from anaesthesia, as assessed by the awakening after the discontinuation of N2O administration, was more rapid in patients given glycopyrrolate. In conclusion, glycopyrrolate seems to have advantages over atropine when used during reversal of pancuronium block with neostigmine.

Adult↗