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Biomedical subjects

H Blomqvist

Publications and source records attributed to H Blomqvist.

34 records · Page 2Linked to original sources
PubMed1991

Furosemide, when used in combination with positive end-expiratory pressure, facilitates the resorption of extravascular lung water in experimental hydrostatic pulmonary oedema.

The study aimed to establish whether furosemide given intravenously improved resorption of hydrostatic pulmonary oedema in 14 dogs mechanically ventilated with positive end-expiratory pressure (PEEP). Hydrostatic pulmonary oedema was created by simultaneous inflation of a left atrial balloon and rapid intravenous infusion of isotonic saline. The hydrostatic process was terminated by deflating the balloon and reducing the infusion rate. A PEEP of 10 cmH2O (1.0 kPa) was applied in all animals; in seven, furosemide was administered (diuretic group), 1 mg/kg intravenously as a bolus followed by an infusion of 0.5 mg/kg per hour, while the remaining seven dogs served as a control group. All dogs were studied for a period of 4 h. The extravascular lung water measured with the double indicator dilution technique was 28.3 +/- 3.8 (diuretic group) and 28.2 +/- 6.8 ml/kg (control group) during maximum oedema. It was reduced to 16.4 +/- 2.2 (diuretic group) vs 19.8 +/- 3.7 ml/kg (control group) after 4 h of resorption, P less than 0.05. Postmortem gravimetric values of extravascular lung water were 9.1 +/- 3.4 (diuretic group) vs 12.6 +/- 5.0 g/kg (control group). In the diuretic group the urinary output increased threefold, and haemoglobin and serum protein concentrations were higher than in the control group. There was a significantly greater decrease in cardiac output and central blood volume in the diuretic group. In conclusion, furosemide given intravenously improved lung fluid resorption in hydrostatic pulmonary oedema, probably by increasing the plasma colloid osmotic pressure.

Animals↗
PubMed1991

Does PEEP facilitate the resolution of extravascular lung water after experimental hydrostatic pulmonary oedema?

The effect of mechanical ventilation with positive end-expiratory pressure on the resolution of hydrostatic pulmonary oedema created by temporary left atrial balloon inflation was studied in mechanically ventilated dogs. Immediately after the hydrostatic process was terminated, by deflating the left atrial balloon, the animals were ventilated for 4 h with zero end-expiratory pressure (ZEEP, n = 6) or with a positive end-expiratory pressure (PEEP, n = 6) of 1.0 kPa (10 cmH2O). Gas exchange and extravascular lung water content (EVLW) with the double indicator dilution technique (dye/cold) were studied and gravimetric determination of lung water was made postmortem. EVLW decreased from 31.6 +/- 7.3 mean +/- SD ml.kg.1 during maximal oedema to 14.5 +/- 2.1 ml.kg.1 (p less than 0.001) 4 h after deflation of the left atrial balloon in dogs ventilated with ZEEP. The corresponding values in dogs ventilated with PEEP were a reduction in EVLW from 28.0 +/- 4.1 to 20.7 +/- 4.0 ml.kg.1 (p less than 0.01) (mean decrease 7.3 +/- 4.0 ml.kg.1). EVLW was significantly higher after 4 h on PEEP than after ZEEP (p less than 0.01). Gravimetric values at the end of the experiment were 12.4 +/- 2.8 ml.kg.1 (ZEEP) and 14.7 +/- 4.5 ml.kg.1 (PEEP) (NS). Oxygenation improved in both groups during the resolution of oedema with a more evident and early effect in the PEEP group. It is concluded that mechanical ventilation with PEEP of 1.0 kPa (10 cmH2O) in the resolution phase after experimental hydrostatic oedema improves oxygenation but retards the resolution of oedema.

Animals↗
PubMed1990

Lung fluid balance evaluated by the rate of change of extravascular lung water content.

Lung fluid balance was studied in 27 mongrel dogs by measuring changes in extravascular lung water content (EVLW). The expression delta EVLWi, which is the difference in EVLWi per kilo bodyweight per hour between two measurement occasions, was used as an estimate of the rate of change of EVLW. EVLW was measured by a double-indicator dilution technique (EVLWi) using iced glucose and indocyanine green. In addition, EVLW was determined at the end of each experiment with gravimetric technique (EVLWg), which enabled the calculation of a regression equation between EVLWi and EVLWg. Delta EVLWi was calculated repeatedly during an 8-h period of mechanical ventilation (MV) with no application of a positive end-expiratory pressure (n = 5), during an 8-h period with a positive end-expiratory pressure (PEEP) of 10 cmH2O (1.0 kPa) (n = 5), during the development of oleic acid (OA)-induced pulmonary oedema (n = 7), and hydrostatic pulmonary oedema (left atrial balloon inflation) (n = 9). An increase of EVLW was seen during PEEP 8 h (mean 35%) and after induction of OA and hydrostatic oedema (mean 300%), but no change was found during MV without PEEP. The regression equation was EVLWi = 5.5 + 0.97 x EVLWg (P = 0.001, r = 0.90). OA-induced oedema caused a mean maximum delta EVLWi of 5.1 ml/kg/h, indicating capillary leakage which, however, was self-limiting within 2 h after OA injection. In hydrostatic oedema there was a maximum delta EVLWi of 16.0 ml/kg/h. Delta EVLWi was negative after deflation of the left atrial balloon, indicating reabsorption of oedema.

Animals↗
PubMed1990

Measurement of dynamic lung fluid balance in the mechanically ventilated dog. Theory and results.

An expression (LN) is presented for the net fluid leakage from the intravascular to the extravascular space in the lung. It is based on a new dog model and is the sum of rate of change in extravascular lung water content (EVLW), thoracic lymph flow, and pleural fluid formation. The rate of change of EVLW (delta EVLW) in ml/kg/h was calculated from repeated measurements of EVLW with a double-indicator dilution technique (dye/cold) and corrected according to the relation between EVLW measured by this technique and gravimetry. LN was studied in lung-healthy mechanically ventilated dogs during a prolonged period of mechanical ventilation with and without the application of a positive end-expiratory pressure of 10 cmH2O (1.0 kPa). During mechanical ventilation, LN was found to be 0.3 ml/kg/h in the basal condition, increasing to 0.5 ml/kg/h (P less than 0.01) after a mean period of 7 h. After the application of a positive end-expiratory pressure (PEEP) of 10 cmH2O (1 kPa) for 0.5-2 h, LN was found to increase significantly, from a mean of 0.3 ml/kg/h to 0.9 ml/kg/h (P less than 0.01). We conclude that LN is a useful quantitative expression in experimental studies on lung fluid balance.

Animals↗
PubMed1990

Net fluid leakage (LN) in experimental pulmonary oedema in the dog.

Net fluid leakage (LN) from the intravascular to the extravascular pulmonary space was estimated in anaesthetised dogs after injection of oleic acid (OA) (n = 8), or after hydrostatic pressure elevation by inflation of a left atrial balloon (n = 5). LN was calculated as the sum of: (i) rate of change in extravascular lung water (delta EVLW), (ii) thoracic lymph flow, and (iii) pleural fluid formation per time unit. Pleural fluid formation was measured in five dogs with hydrostatic or OA induced pulmonary oedema and was 1.8 +/- 0.9 ml/kg/h. In OA-induced pulmonary oedema, LN increased to a peak of 9.2 ml/kg/h within 2 h after OA injection. Thereafter LN fell and was 2-4 ml/kg/h during the succeeding 2-4 h. During hydrostatic pulmonary oedema LN was increased to as much as 13 ml/kg/h, but it became negative, -5 to -8 ml/kg/h (reabsorption of extravascular fluid) as soon as pulmonary vascular pressures returned to normal following deflation of the left atrial balloon. We conclude that in both forms of oedema there is an initial rapid leakage. In OA-induced oedema this leakage continues, although at a slower rate, whereas in hydrostatic oedema there is a considerable net fluid absorption from the pulmonary extravascular to the intravascular space as soon as vascular pressures are brought to normal levels.

Animals↗
PubMed1987

Selective mechanical ventilation of dependent lung regions in the anaesthetized horse in dorsal recumbency.

The effect of selective mechanical ventilation of dependent lung regions were studied in anaesthetized horses (mean weight 486 kg) in dorsal recumbency. Blood-gas measurements were performed with the horse in the lateral position during spontaneous breathing (before selective intubation) and in dorsal recumbency during spontaneous breathing, general mechanical ventilation, and spontaneous breathing + selective mechanical ventilation. Arterial oxygen tension (PaO2) was 32.3 kPa in the lateral position during spontaneous breathing with a high inspired oxygen fraction (FlO2 greater than 92%). In dorsal recumbency PaO2 decreased to 10.9 kPa during spontaneous breathing and was not significantly affected by general mechanical ventilation (PaO2 12.6 kPa). The institution of selective mechanical ventilation with a selective positive end-expiratory pressure (PEEP) of 20 cm H2O caused a marked increase in PaO2 to an average of 35.3 kPa. It is concluded that selective intubation of dependent regions in the diaphragmatic lobes is a feasible procedure and that selective mechanical ventilation with PEEP markedly improves arterial oxygenation in the anaesthetized horse in dorsal recumbency.

Anesthesia, General↗
PubMed1987

Separate lung blood flow in anesthetized dogs: a comparative study between electromagnetometry and SF6 and CO2 elimination.

Anesthetized, prone dogs were intubated with a double-lumen endobronchial tube, and the lungs were ventilated independently. Three methods of recording differential blood flow were compared during unilateral lung hypoxia: electromagnetic flow measurement, flow probes being fitted onto each main pulmonary artery after thoracotomy (QPr); SF6 elimination from each lung, the inert gas being continuously infused into a central vein (QSF6); and CO2 elimination (QCO2). During control conditions (100% O2 to both lungs), the test lung QPr was 54% of cardiac output, and corresponding QSF6 and QCO2 were 56% and 52%, respectively. Hypoxic challenge with 8% O2 to the test lung reduced QPR, QSF6, and QCO2 by 25%, 27%, and 7%, respectively. Ventilation of the test lung with pure nitrogen reduced its blood flow further, QPr, QSF6, and QCO2 being reduced by 39%, 42%, and 23%, respectively, from initial control. A strong correlation between test lung QPr and QSF6 was seen with a slope of 0.90 (r:0.89, P less than 0.001). Only 60% of the reduction in test lung blood flow was detected by CO2 elimination, as compared to electromagnetic flow measurement or SF6 elimination. The poor results obtained with CO2 elimination can be explained by its dependence on the ventilation-perfusion ratio and the effect of oxygen tension on the CO2 binding capacity of blood (Haldane effect). The findings emphasize the necessity of using an inert, poorly soluble gas for the measurement of separate lung blood flow.

Anesthesia↗
PubMed1987

Thoracic and abdominal lymph drainage in relation to mechanical ventilation and PEEP.

Thoracic and abdominal lymph flow have been studied in 25 dogs. Thoracic lymph flow (TLF) was found to be (mean +/- s.e. mean) 6.1 +/- 1.4 ml/h before, and 29 +/- 4.6 ml/h after the induction of lung damage with oleic acid. TLF was depressed by 50% both before and after lung damage, when a positive end-expiratory pressure (PEEP) of 1.0 kPa (10 cmH2O) was applied. This suggests impeded drainage of the lung tissue. Spontaneous breathing, compared to mechanical ventilation, significantly increased TLF by approximately 70%. Abdominal lymph flow increased from 61 +/- 5.3 ml/h to 111 +/- 12.6 ml/h, when a PEEP of 1.0 kPa was applied. These findings demonstrate that PEEP may contribute to oedema in a surgical area. It is concluded that increased intrathoracic pressure reduces TLF, and spontaneous breathing increases TLF, as compared to mechanical ventilation without PEEP.

Abdomen↗
PubMed1987

Effects of PEEP on extravascular lung water and central blood volume in the dog.

Twenty-four mongrel dogs were anaesthetized and ventilated mechanically in the supine position. Extravascular lung water (EVLW) and central blood volume (CBV) were measured with a double indicator (dye/cold) dilution technique. Both indicators were detected intravascularly in the aortic root with a fibreoptic thermistor catheter. Seven dogs ventilated with a positive end-expiratory pressure (PEEP) of 1.0 kPa (10 cmH2O) for a short period of time (less than 20 min) displayed no significant change in EVLW as measured with the indicator dilution technique (= EVLWi), while reductions were seen in both CBV (15%, P less than 0.01) and cardiac output (CO-thermodilution technique) (10%, P less than 0.05). Another seven dogs ventilated with a PEEP of 1.0 kPa for 8 h showed a gradual increase in EVLWi. After 8 h, a mean increase of 34% (P less than 0.01) was recorded, and the increase was also verified by post-mortem gravimetric determination of EVLW (= EVLWg), displaying an increase of 61% (P less than 0.01). In five dogs ventilated with zero end-expiratory pressure (ZEEP) for 8 h, no changes in EVLWi, CO, and CBV were observed, and EVLWg was mean 4.39 g/kg body weight (BW). Five additional dogs were sacrificed after 15 min of anaesthesia without catheterization and EVLWg was found to be 4.24 g/kg BW. It is concluded that EVLWi does not change measurably during ZEEP or short periods of PEEP. However, long periods (8 h) of PEEP result in elevated EVLWi values. Gravimetry supports these conclusions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effects of prolonged surgical trauma on the extravascular lung water and central blood volume in the dog.

Extravascular lung water (EVLW) and central blood volume (CBV) were measured in 13 dogs with a double-indicator dilution technique (dye-cold), the indicators being detected intravascularly. Animals in a control group (n = 5) were mechanically ventilated for 8-15 h after baseline measurements. Another group of animals (n = 8) were subjected to extensive lymph duct cannulations, including a thoracoabdominal incision, and the dogs were followed for 8 to 18 h postoperatively. All dogs (n = 13) then received a dose of oleic acid intravenously in order to create lung damage. A positive fluid balance was maintained throughout the experiment. Basal EVLW was 8.8 ml/kg (n = 13) (similar in both groups), and did not change significantly in either group before oleic acid. Basal CBV was 18.5 ml/kg (n = 13); it increased (P less than 0.05) in the control group and decreased (P less than 0.05) in the surgery group during a 8-15-h period. EVLW was doubled (P less than 0.001) and CBV decreased slightly 2 h after oleic acid administration. The lung damage was similar in both groups, and was accompanied by increased pulmonary vascular pressures and marked reductions in arterial oxygen tension and thoracic compliance. The findings suggest that an earlier proposed dog model for the simultaneous measurement of EVLW and lymph flow can be used in long-term studies on lung fluid balance.

Anesthesia↗
PubMed1986

An experimental model for the separate sampling of thoracic and abdominal lymph.

A new animal model for the selective sampling of both the thoracic and the abdominal lymph is presented. Separation of the abdominal from the thoracic lymph flow provides new information on pulmonary physiology during mechanical ventilation and is a prerequisite for studies on pulmonary lymph flow. This is underscored by the observation that the abdominal contribution to the total lymph flow in the neck is more than 90%.

Abdomen↗
PubMed1986

Separate thoracic and abdominal lymph flow in the dog.

We present results from an improved dog model, in which lymph flows from the thorax and abdomen are separated. The effect of increased alveolar pressure on lymph flows was studied by the application of positive end expiratory pressure (PEEP). Mean (+/- SD) thoracic lymph flow in 10 dogs was 4.1 ml/h (+/- 2.9) before, and 27.0 ml/h (+/- 17) after the induction of lung damage with oleic acid. Thoracic lymph flow was depressed by 50% with the application of a PEEP of 1.0 kPa (10 cm H2O), both before and after lung damage, thus impeding the drainage of the lung tissue. Abdominal lymph flow increased from 57 +/- 29 ml/h to 111 +/- 65 ml/h with the application of a PEEP of 1.0 kPa. These simulated events in a surgical area demonstrate the risk of causing excessive edema with PEEP. We conclude that if the application of PEEP in a clinical situation is necessary then the additional risk factors (increased extravascular lung water, increased edema in surgical areas) that have been presented should be taken into consideration.

Abdomen↗
PubMed1984

Differential ventilation with selective PEEP in bilateral lung disease.

A patient with severe, acute respiratory failure (ARF) due to bilateral lung disease has been treated with a new ventilation concept aimed at improving the vertical match of ventilation and perfusion. The patient suffered from severe hypoxemia in spite of artificial ventilation with high PEEP and high inspired oxygen fraction. He was intubated with a double lumen bronchial catheter and placed in the lateral decubital posture, whereafter each lung was ventilated in accordance with its assumed perfusion, and selective PEEP of 10-15 cm H2O to the dependent and 0-5 cm H2O to the non-dependent lung was applied. Differential ventilation with selective PEEP resulted in a substantial improvement in pulmonary gas exchange in two separate periods of 3-4 days. The technique thus proved to be efficient and also clinically feasible in a standard intensive care unit.

Aged↗
PubMedDate not supplied

Is glucose-free bupivacaine isobaric or hypobaric?

Spinal anesthesia with 0.5% glucose-free bupivacaine was given to 20 patients lying in the lateral decubitus position during lumbar injection and for 30 minutes after. The mean maximum level of anesthesia after 30 minutes was Th:8 in the nondependent side and Th:9 in the dependent side. The difference in cephalad level of analgesia between the two sides during the initial 30 minutes was significant. Fourteen patients experienced some degree of hypoalgesia during the initial 30 minutes in the dependent side but not in the nondependent side. The degree of motor blockade also showed significant difference between the dependent and nondependent side except at five minutes. These findings indicate glucose-free bupivacaine 0.5% is hypobaric in clinical conditions.

Anesthesia, Spinal↗