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Biomedical subjects

O Meretoja

Publications and source records attributed to O Meretoja.

14 recordsLinked to original sources
PubMed1999

Advantages of fentanyl over morphine in analgesia for ventilated newborn infants after birth: A randomized trial.

OBJECTIVE: To compare the efficacy and adverse effects of fentanyl or morphine analgesia during the first 2 days of life in newborn infants who underwent mechanical ventilation. STUDY DESIGN: In a randomized double-blind trial, 163 infants were allocated to receive a continuous infusion of fentanyl (10.5 microg/kg over a 1-hour period followed by 1.5 microg/kg/hr) or morphine (140 microg/kg over a 1-hour period followed by 20 microg/kg/hr) for at least 24 hours. The severity of pain was assessed with physiological parameters, a behavioral pain scale, and stress hormone concentrations before and 2 and 24 hours after the start of treatment. RESULTS: The analgesic effect was similar in both groups, as judged by the pain scale. Plasma adrenaline and noradrenaline concentrations decreased significantly from 0 to 24 hours in both groups. Median adrenaline decrease was 0.5 nmol/L (interquartile range [IQR] 1.1;0.0) in the fentanyl and 0.7 nmol/L (IQR 1.3;0.1) in the morphine group, noradrenaline 2.1 nmol/L (IQR 9.0;0.2), and 3.0 nmol/L (IQR 7. 5;0.3), respectively. beta-endorphin decreased significantly only in the fentanyl group ( 14 pmol/L (IQR 28; 7), P <.05). Decreased gastrointestinal motility was less frequent in the fentanyl group (23% vs 47%, P <.01). CONCLUSIONS: With at least as effective analgesia as with morphine, fentanyl had fewer side effects. Fentanyl may be superior to morphine for short-term postnatal analgesia in newborn infants.

Analgesics, Opioid↗
PubMed1991

Disturbance in respiratory mechanics with extreme truncal flexion during anaesthesia in children.

Respiratory mechanics were studied in five anaesthetised children, aged 3 to 33 months undergoing urological surgery, in both the supine position and with extreme truncal flexion. Extreme truncal flexion was associated with a reduced respiratory system compliance. Dynamic compliance decreased significantly, by 30% (range 12-55%) and static compliance decreased significantly, by 40% (range 18-65%). There were no changes in respiratory system resistance. Tidal volume was also significantly reduced (mean 20%) despite a significant increase (mean 22%) in peak ventilator pressure. These changes in mechanics must be recognised to avoid alveolar hypoventilation, with a consequent decrease in gas exchange during surgery.

Anesthesia, General↗
PubMed1989

Serum fluoride in children anaesthetized with enflurane.

The serum inorganic fluoride concentration (SF) was measured in 40 children aged 22 days to 11 yrs (five infants) undergoing enflurane anaesthesia lasting 20-200 min, at an inspiratory concentration of 0.8 or 1.0%. Regardless of age, SF peaked at 2-8 mumol l-1 after 20-40 min of enflurane exposure, and at 4-10 mumol 1-1 and 6-10 mumol l-1 after 41-90 min and 91-200 min of exposure, respectively. The highest individual value was 12.5 mumol l-1. Another 23 children, aged 1-16 yrs, received 0.8% enflurane for 60 min. The increase in SF was 3-9 mumol l-1, with no clear dependence on age. Altogether, the increase in SF was comparable to that detected in adults after anaesthesia of equal duration.

Aging↗
PubMed1988

Can barbiturate anaesthesia cure infantile spasms?

Five patients with infantile spasms and hypsarrhythmia and one with Lennox-Gastaut syndrome were treated with brief thiopentone anaesthesia as the primary treatment of infantile spasms. Thiopentone (30 mg/kg) was given intravenously and burst suppression was reached in EEG in three patients by this dose. The results were disappointing. In three patients a transient beneficial effect on spasms and hypsarrhythmia was seen, but all patients relapsed. Three other patients had anaesthesia for surgery. The spasms ceased and hypsarrhythmia disappeared dramatically, and the effect was permanent. The possible mechanisms of the therapeutic effect are discussed. It seems advisable to give anaesthesia and surgery prior to steroid treatment in any case where the both are needed.

Anesthesia↗
PubMed1987

Atrial natriuretic peptide in patent ductus arteriosus.

Plasma concentrations of atrial natriuretic peptide (ANP) were measured in nine infants (age 4 days-9 months) before and after closure of patent ductus arteriosus. Initially all patients had marked distention of the left atrium as indicated by a left atrium to aortic root ratio greater than or equal to 1.3 on echocardiography. After closure of the ductus, operative in six and pharmacological in three patients, left atrial size normalized (left atrium to aortic root ratio less than 1.3) in all patients, except in one treated surgically. Before closure the plasma concentration of ANP was 86-2224 pg/ml and after closure 44-1400 pg/ml. There was a significant correlation between the size of left atrium and plasma concentration of ANP (r = 0.56; p = 0.01). Our results suggest that in infants with patent ductus arteriosus the left atrium is the main source of ANP. The secretory rate of ANP decreases immediately after restoring left atrial size by closure of the ductus.

Atrial Natriuretic Factor↗
PubMed1984

Myocardial oxygen balance during hemodilution in patients undergoing coronary artery bypass grafting.

The myocardial (arterial-coronary sinus) balance of oxygen and lactate was studied before a cardiopulmonary bypass and during the first 5 min of a normothermic bypass in two patient groups undergoing coronary revascularization for multiple coronary artery disease. The hemodilution (HD) group was hemodiluted before the bypass with dextran 70 (15 ml/kg; resulting mean hematocrit 32%) and further at the beginning of the bypass due to nonhemic priming of the oxygenator (mean hematocrit 15%). The control (C) group was not diluted before the bypass, and four units of red blood cells were included in the oxygenator priming (mean hematocrit 27% after the beginning of the bypass). The preoperative dilution produced a decline in the coronary sinus blood oxygen tension and oxygen saturation, but no change in the arterial-coronary sinus lactate balance. After the first 5 min of the bypass, the heart produced lactate in both the HD group and the C group, but the lactate production was more pronounced in the HD group. At the same time, the coronary sinus blood oxygen saturation was lower in the HD group than in the C group. Hypotension frequently accompanied the beginning of the bypass in both groups. It is concluded that the hemodilution to a hematocrit level of 32% in patients undergoing coronary revascularization for multiple stable coronary artery disease produces compensatory changes in myocardial oxygen extraction, but no changes of a generalized ischemia can be demonstrated. The hemodilution to a hematocrit level of 15% produces myocardial ischemia in patients with a normothermic unloaded heart, adding to the effect of hypotension at the beginning of the bypass.

Adult↗
PubMed1983

Effects of extreme haemodilution on the immediate post-operative course of coronary artery bypass patients.

The immediate post-operative course was investigated in 70 patients who had undergone coronary artery bypass grafting under normovolaemic moderate and subsequent extreme haemodilution, and in 70 control patients who underwent a similar operation with a haemic prime in the heart-lung machine. Altogether 8 patients (5.7%), 4 from the haemodilution group and 4 from the controls required re-exploration for excessive post-operative bleeding and were examined as their own group. There were no marked differences in bleeding through chest tubes or in blood haemoglobin concentration between patients who had undergone intra-operative haemodilution and controls. Post-operatively both patient groups required approximately analogous amounts of infused blood, colloids and crystalloids. Central venous pressure was consistently lower in haemodiluted patients. Opening of peripheral circulation as indicated by a rise in skin temperature occurred significantly faster in haemodiluted patients than in controls. Before and after weaning from the respirator, arterial blood oxygen tension was slightly lower in patients who had undergone intra-operative haemodilution. Serum creatinine levels were lower and blood platelet counts significantly higher in haemodiluted patients than in controls. Rates of peri-operative myocardial infarctions showed no essential difference between the groups.

Adult↗
PubMed1982

Severe bronchiolitis probably caused by varicella-zoster virus.

An unusual, severe pneumonia probably caused by varicella-zoster virus is reported in a 19-year-old previously healthy man. The diagnosis was based on high titer of varicella-zoster antibodies in serum, and demonstration of varicella-zoster antigen from lung biopsy specimen. The uncommon feature in the pathophysiological course of the disease was the selective hypercarbia that responded well to bronchodilator therapy with theophylline. Furthermore, the patient had no skin manifestations during his illness.

Adult↗
PubMed1982

Can central venous blood replace mixed venous blood samples?

To estimate the value of central venous blood as representative of real changes in pulmonary shunt (Qsp/Qt), mixed venous oxygen saturation and arteriovenous oxygen content difference [C(a-v)O2] during active phases of adult intensive care therapy, 86 blood samples were withdrawn from 42 patients as quadruple simultaneous collections from systemic artery, pulmonary artery (PA), superior caval vein (CV) and right atrium (RA). We found a significant positive correlation of the measured variables and especially of the subsequent changes of these variables in individual patients between PA blood samples and both CV and RA blood samples (p less than 0.001). We, therefore, conclude that a central venous catheter can replace the PA catheter to collect blood representative of mixed venous blood samples for the above purposes. However, the exact numerical value of mixed venous blood samples can only be measured from blood collected from the PA itself.

Blood Gas Analysis↗
PubMed1981

Oxygen transport to tissue under normovolemic moderate and extreme hemodilution during coronary bypass operation.

Oxygen transport to tissue was studied in 12 patients undergoing coronary bypass operation under normovolemic moderate and extreme hemodilution. Normovolemic moderate hemodilution (15 ml per kilogram of body weight), carried out immediately after induction of anesthesia, decreased the mean hematocrit from 0.43 to 0.33. Simultaneously, the cardiac index and the left ventricular filling pressure increased slightly but the systemic oxygen transport was reduced by 20%. The subcutaneous tissue oxygen tension (PO2) was approximately 40 mm Hg after induction of anesthesia and underwent a transient increase during moderate hemodilution. During cardiopulmonary bypass and extreme hemodilution, the mean hematocrit declined to 0.16. Concurrently, the mean tissue PO2 fell sharply and reached a minimum of 14 mm Hg at deepest hypothermia. After decannulation and reinfusion of autologous blood, the PO2 rose to 30 mm Hg. In general, total-body oxygen consumption changed along with tissue PO2. Blood lactate concentration underwent a clear increase in the early phase of extracorporeal circulation and remained rather stationary thereafter. No perioperative myocardial infarctions were encountered, and each patient made an uneventful recovery.

2,3-Diphosphoglycerate↗
PubMed1981

Oxygen transport and tissue oxygenation under moderate and extreme hemodilution during coronary bypass surgery.

Oxygen transport and tissue oxygenation were investigated in twelve patients undergoing coronary bypass surgery under normovolemic moderate and extreme hemodilution. Moderate hemodilution, that was carried out after induction of anesthesia, decreased the mean hematocrit from 0.43 to 0.33. Concurrently, the cardiac index and the left ventricular filling pressure increased slightly whereas the systemic oxygen transport declined by 20%. This was associated with elevated oxygen extraction. The subcutaneous tissue oxygen tension underwent a transient increase during moderate hemodilution. During cardiopulmonary bypass and extreme hemodilution the mean hematocrit declined to 0.16. Simultaneously, the tissue PO2 decreased clearly reaching its minimum at the deepest hypothermia. After coming off bypass and reinfusion of the autologous blood the tissue PO2 approached the preoperative levels. In general, total body oxygen consumption changed parallelly with the tissue oxygen tension. Lactate concentration in the mixed venous blood increased in the beginning of the extracorporeal circulation and remained rather stationary thereafter. All patients recovered normally without any perioperative myocardial infarctions.

Adult↗
PubMed1981

Serum oncocity and myocardial oxygen balance during haemodilution in open-heart surgery.

In the first part of the present study the colloid-oncotic properties of degraded gelatin and dextran 70 were compared with each other during moderate normovolemic and extreme haemodilution. Serial serum analyses of colloid oncotic pressure and albumin concentration were performed on 39 open-heart surgery patients. The profile of albumin changes during the 24-hour period beginning with preanaesthetic measurements was identical in both colloid-groups. The data obtained strongly support the supposition that the gelatin solution easily escapes from the circulation due to gelatin's low number average molecular weight. On the other hand the oncotic and haemodynamic effects of dextran 70 may continue for many hours; dextran 70 seems therefore to be an ideal colloid for haemodilution. The second part of the study comprised an investigation of the effects on myocardial oxygen and lactate balance of moderate and extreme haemodilution with dextran 70 on 11 patients undergoing coronary bypass surgery. To compensate fully for the observed decrease in the blood O2-capacity during normovolemic haemodilution (Hct fell from 44 to 32), the coronary blood flow should have been increased by 24% in addition to the increase observed in the myocardial oxygen extraction. The compensation was considered adequate, because no myocardial ischaemia, as judged by the unchanged myocardial lactate balance, developed. The coronary sinus blood samples are, however, a poor reflection of local myocardial metabolic changes in those areas, where coronary flow is most severely restricted.

Blood Physiological Phenomena↗
PubMed1980

Carbon dioxide transportation and haemoglobin oxygen affinity during haemodilution.

The increase in the PCO2 of tonometered, haemodiluted (Hct 15%) blood samples was on an average 8 mm Hg higher than in the undiluted samples of the same blood when a fixed amount of Co2 was added to both samples. Concurrently the actual P50 increased on an average 2 mm Hg more in the diluted than in the undiluted samples. In a series of patients undergoing coronary artery bypass grafting the arterial-mixed venous PCO2 difference was on an average 5 mm Hg higher during haemodilution (Hct 16%) than in the control situation. In another series of similar patients the arterial-coronary sinus PCO2 difference increased from 9 +/- 1 to 14 +/- 2 mm Hg when the Hct fell to the level of 22%. The haemodilution-induced decrease in the total CO2-transporting capacity of the blood leads to an increased PCO2 and a decreased pH as compared to the situation without haemodilution, if the same amount of CO2 is added. In the clinical situation the gained decrease of the haemoglobin oxygen affinity probably plays a part in the compensation for the decreased oxygen capacity of the blood caused by the haemodilution.

Carbon Dioxide↗