Is compartment pressure related to plasma colloid osmotic pressure, in patients during and after cardiac surgery?

Haemodilution is always considerable during cardiopulmonary bypass (CPB). If this extra fluid sits in the muscle compartments then a corresponding rise in the compartment pressure (CP) is to be expected. The aim of this study was to measure pressure changes in a body compartment with new equipment, the MTC (Microtransducer). Changes in plasma colloid osmotic pressure (COP) were also measured during and after CPB to find a connection, if any, between CP and plasma COP. Ten elective consecutive CPB patients were studied. A 3-French (3-F) catheter-size electronic MTC was inserted in an anterior tibial compartment before CPB. The CP was monitored for 48 h. Plasma COP was also measured before, during and after CPB. CP increased significantly during and after CPB in all patients (p=0.01). COP decreased significantly in all patients (p=0.005), but no correlation was found between changes in COP and CP values in this study. Most of the patients reached their highest CP just after weaning off bypass. The CP remained elevated for 48 h, even though it then tended to decrease again. None of the patients reached the starting value within 48 h. COP decreased rapidly after going on bypass, but returned towards its starting value approximately 6 h after bypass. It is concluded that CP increases considerably during and after CPB and stays increased for at least 2 days after CPB. COP decreases during CPB, but reaches normal values 6 h after the CPB. No correlation was found between changes in CP and COP The MTC is a safe and easy way to measure intracompartment pressure.     

Protein and colloid osmotic pressure changes with albumin and/or saline replacement during plasma exchange

Colloid osmotic pressure (COP) has been used as a predictor of fluid egress from the vascular space and edema development in the lungs and elsewhere. We investigated the relative safety, as predicted by the COP, of 5 percent albumin plus saline and 5 percent albumin alone as replacement fluids during plasma exchange. Fifty-three one and one-half plasma volume exchanges were performed in 15 patients with a variety of diagnoses using intermittent flow cell separators. On specimens obtained, before, during, and after each plasma exchange, the COP was measured directly with a membrane oncometer, and total protein, albumin, and protein electrophoresis were determined using standard biochemical techniques. COP dropped significantly with one to one 5 percent albumin replacement but even more with one-half 5 percent albumin and one-half saline replacement during the exchange. COP did not fall below 12.5 torr at the end of the plasma exchange, even with one-half saline replacement, compared to the 10 to 12 torr level at which pulmonary edema might be expected. The fall in COP during exchange when saline was given first did approach this range but rapidly reversed itself with albumin administration. Clinically, no evidence of tissue or pulmonary edema was observed. Recovery in total protein and COP between plasma exchanges was significant.     

Hemodynamic and colloid osmotic pressure alterations in the surgical patient

Colloid osmotic pressure (COP) was measured simultaneously with cardiorespiratory measurements in 103 surgical patients suspected of having circulatory problems. In a small subset of 28 patients, measurements were taken before, during, and after surgical operations. Similarly, data sets were taken before, during, and after infusions of colloids and crystalloids to assess the interactions of these variables during the stress of surgery and the administration of fluid therapy. COP was found to decrease during and shortly after surgical operations despite reasonably well-maintained pressure, volume, and flow variables. Concentrated (25%) albumin and plasma protein fraction (PPF) increased COP, cardiac index (CI), CVP, pulmonary capillary wedge pressure (WP), and blood volume, whereas crystalloids transiently increased CI, CVP, and WP but did not significantly change COP and blood volume. Low COP values were weakly related to survival, and COP-WP differences less than or equal to 3 mm Hg were roughly related to ARDS and pulmonary edema.     

小儿心内直视手术控制胶体渗透压的研究

目的：探讨小儿心脏直视手术围体外循环期胶体渗透压的变化规律。方法：将68例先心病患儿随机分成4组，分别以晶体液、血浆、人血白蛋白、血定安预充，观察胶体渗透压和临床一些指标的变化及比较组织的湿干重比。结果：以人血自蛋白、血定安预充与以晶体液、血浆预充相比，前两者能够在体外循环中维持较理想的胶体渗透压；组织的湿干重比升高幅度较小；术后辅助呼吸时间较短，出现眼球结膜、眼睑水肿的比率较低。结论：维持小儿体外循环过程中适当的胶体渗透压有助于患儿康复，减少并发症；以人血自蛋白和血定安预充能够较好维持所需水平的胶体渗透压，且安全、有效。     

成人心脏围术期胶体渗透压变化及其临床意义

目的 探讨成人心脏外科手术围术期血浆胶体渗透压(COP)的变化规律。方法 选择21例行成人心脏外科手术的患者,根据手术不同分为体外循环瓣膜置换组(CPB组)、微创不停跳冠脉搭桥组(OP组)。记录麻醉后5min(T0)、体外循环开始后5min/搭桥血管远端时(T1)、体外循环结束后5min/搭桥血管近端时(T2)、手术结束返回ICU(T3)、术后2h(T4)、4h(T5)、8h(T6)、24h(T7)的COP,以及术后3d检验指标的变化、机械通气时间、ICU时间等数据。比较各时间点的数据差异。结果 所有患者术前基本情况相同。2组患者围术期COP均有下降,但组间比较差异无统计学意义(P0.05)。CPB组在术中COP变化值最明显,差异有统计学意义(P0.05)。2组的并发症发生率及术后ICU时间、机械通气时间比较,差异均无统计学意义(P0.05)。结论 心脏体外循环手术可使COP下降,但通过纠正COP均能恢复正常,对临床预后无明显影响。     

Plasma colloid osmotic pressure in healthy infants

Background  

The plasma colloid osmotic pressure (COP) plays a major role in transcapillary fluid balance. There is no information on plasma COP of healthy infants beyond the first post-natal week. The normal COP in healthy adult subjects (25 mmHg) is currently also applied as a reference value for healthy infants. This study was designed to test whether plasma COP values in healthy infants are the same as those in normal adults.     

Rifampin blood and tissue levels in patients undergoing cardiac valve surgery.

Single 600-mg capsules of rifampin were given orally to 26 patients as prophylaxis during cardiac valve replacement. Antibiotic concentrations were measured in blood (serum or plasma) and tissue (excised cardiac valve). The serum or plasma levels of rifampin in 18 patients who ingested this drug 2 h before they received preoperative opiates and anticholinergics intramuscularly were not significantly different from the levels in four normal volunteers who received the drug. These levels were 15.9 +/- 6.5 micrograms/ml (mean +/- standard deviation) 2 h after drug administration, 7.1 +/- 4.3 micrograms/ml 8 h after drug administration and 2 h after a mean of 1.4 h on cardiopulmonary bypass, and 1.6 +/- 1.6 micrograms/ml 24 h after drug ingestion. The valve tissue level was 3.8 +/- 2.7 micrograms/g (mean +/- standard deviation; n = 10). This value was 65% of the simultaneous serum and plasma levels and 31% of the peak serum and plasma levels. Eight patients who were given rifampin at the same time that they received other preoperative medications had significantly lower blood levels than the 18 patients who received rifampin 2 h earlier (P less than 0.001). No rifampin was detected in valves from seven of these patients. Decreased rifampin absorption due to simultaneous administration with opiates and anticholinergics was the probable reason for the low plasma and serum levels observed. These data suggest that, if properly dosed, rifampin administered orally gives high blood and valve tissue levels, which are affected minimally by cardiopulmonary bypass in patients undergoing cardiac valve surgery.     

Fulminant pulmonary edema after near-drowning: remarkably high colloid osmotic pressure in tracheal fluid

A 44-year-old man developed severe permeability pulmonary edema associated with septic shock after near-drowning. Colloid osmotic pressure (COP) of deep tracheal fluid was persistently higher than plasma COP. Tracheal/plasma COP ratio reached a peak value of 1.75. A massive colloid infusion of 5% protein solution was incriminated in the development of this markedly elevated COP in the tracheal fluid.     

Evidence of Incomplete Left Ventricular Relaxation in the Dog: PREDICTION FROM THE TIME CONSTANT FOR ISOVOLUMIC PRESSURE FALL

Although it has been proposed that incomplete relaxation explains certain increases in left ventricular end diastolic pressure relative to volume, there has been no clear demonstration that incomplete relaxation occurs in the intact working ventricle. To identify incomplete relaxation, left ventricular pressure-dimension relationships were studied in 10 canine right heart bypass preparations during ventricular pacing. The fully relaxed, exponential diastolic pressure-dimension line for each ventricle was first determined from pressure and dimension values at the end of prolonged diastoles after interruption of pacing. For 167 beats during pacing under widely varying hemodynamic conditions, diastolic pressure-dimension values encountered this line defining the fully relaxed state during the filling period indicating that relaxation was complete before end diastole. The time constant for isovolumic exponential pressure fall (T) was determined for all beats. For this exponential function, if no diastolic filling occurred, 97% of pressure fall would be complete by 3.5 T after maximal negative dP/dt. For the 167 beats the fully relaxed pressure-dimension line was always encountered before 3.5 T.     

Effect of cardiopulmonary bypass on the plasma concentrations of fentanyl and alcuronium

This study was conducted to examine the effect of cardiopulmonary bypass surgery on the total and unbound plasma concentrations of fentanyl and the total plasma concentrations of alcuronium. Total fentanyl concentrations were measured by gas chromatography, the plasma protein binding of fentanyl by ultrafiltration, and alcuronium concentrations by high‐performance liquid chromatography. Sixteen patients were studied.
On initiation of cardiopulmonary bypass (CPB), there were mean decreases of 58·8±7·1% and 47±3·2% for total concentrations of fentanyl in plasma and haemoglobin in blood, respectively. The magnitude of these reductions in individual patients was significantly related (Spearman |gr =0·65, P<0·05). The unbound fraction of fentanyl rose from 0·23 to 0·34 after the start of CPB. The total fentanyl concentration remained relatively stable during bypass until near the end of CPB when the mean total concentration increased, coinciding with rewarming. The size of the increase was related to the body mass index (BMI) of the patient (Spearman |gr =0·85, P<0·01). The estimated elimination half‐life of fentanyl using the grouped data was 4·7 h.
The total alcuronium concentration in plasma fell by 29% on initiation of CPB and there was no increase on rewarming. The estimated elimination half‐life of alcuronium using the grouped data was 234 min.
Despite marked declines in the plasma concentrations of both drugs on initiation of CPB, suitable levels of anaesthesia were maintained throughout the procedure.     

Colloid osmotic pressure and fluid resuscitation with hetastarch, albumin, and saline solutions

The effects of fluid resuscitation with 6% hetastarch, 5% albumin, or 0.9% saline solutions on plasma colloid osmotic pressure (COP) were examined in 26 patients with hypovolemic circulatory shock. One liter of hetastarch produced a 36% increase in COP compared to an 11% increase after 1 L of albumin (p less than 0.001). One liter of saline resulted in a 12% decrease in COP (p less than 0.05). The mean COP increased from 16.3 +/- 1.6 (SE) mm Hg to a maximum of 23.7 +/- 1.4 mm Hg during the first 24 h of hetastarch resuscitation (p less than 0.01), and from 17.0 +/- 1.1 to 22.3 +/- 1.5 mm Hg with albumin (p less than 0.001). Saline resuscitation decreased the COP from 17.1 +/- 1.1 mm Hg to a minimum of 12.7 +/- 1.1 mm Hg (p less than 0.02). These changes persisted from 2-5 days after resuscitation. Saline resuscitation required significantly larger amounts of fluid. The authors conclude that fluid resuscitation of circulatory shock with colloid solutions increases COP and requires less volume of resuscitative fluid.     

Penetration of ceforanide and cefamandole into the right atrial appendage, pericardial fluid, sternum, and intercostal muscle of patients undergoing open heart surgery.

Doses of 30 mg of ceforanide or cefamandole per kg were administered intravenously to 26 patients just before their chests were opened for coronary artery bypass or cardiac valve replacement surgery. Samples of right atrial appendage, pericardial fluid, plasma, aortic wall, intercostal muscle, and sternum were obtained at different times after the antibiotic was injected, and these samples were assayed for cephalosporin concentration. For ceforanide the pre-bypass plasma half-life was 2.5 h, and the atrial appendage half-life was 2.1 h; for cefamandole the pre-bypass plasma half-life was 0.75 h and the atrial appendage half-life was 0.72 h. At 3 h the concentrations of ceforanide and cefamandole in atrial appendages were 28.0 and 5.0 micrograms/g, respectively. Ceforanide achieved higher and more sustained concentrations in other tissues than cefamandole. Considering the minimal inhibitory concentrations of these drugs for staphylococci, cefamandole and ceforanide should provide adequate protection against infection by these organisms for the duration of the surgical procedure.     

Effect of haemodialysis on plasma levels of brain natriuretic peptide in patients with chronic renal failure.

1. Plasma human brain natriuretic peptide-like immunoreactivity (hBNP-li) was measured in ten patients with chronic renal failure before and after 4 h of haemodialysis. 2. Plasma hBNP-li was elevated in all patients before dialysis (mean +/- SEM 21.0 +/- 3.8 pmol/l) compared with healthy control subjects (1.3 +/- 0.2 pmol/l, n = 11), but showed considerable inter-patient variability. Before dialysis plasma hBNP-li bore no relationship to the serum creatinine level or to the mean blood pressure. 3. Plasma hBNP-li fell significantly (P = 0.04) during 4 h of haemodialysis. The fall in plasma hBNP-li correlated significantly with the degree of postural blood pressure drop (r2 = 0.44, P = 0.05) and with the fall in body weight (r2 = 0.64, P less than 0.01) after haemodialysis. In all patients, plasma hBNP-li at the end of treatment remained above that in healthy subjects. 4. There was no significant correlation between the fall in plasma hBNP-li and the fall in serum creatinine level, and between the fall in plasma hBNP-li and the fall in supine systolic or diastolic blood pressure, during haemodialysis. 5. We have shown that plasma hBNP-li is elevated in patients with chronic renal failure and is decreased during haemodialysis. The fact that the plasma hBNP-li was not reduced to normal by haemodialysis despite restoration to normovolaemia gives tentative support to the view that, in addition to hypervolaemia, another factor may also be responsible for the elevated plasma hBNP-li seen in these patients.     

Evolution of plasma levels of apolipoprotein B,cholesterol and triglycerides in women during long-term oral contraception

Apolipoprotein B (apo B) was measured by a sensitive and specific double antibody radioimmunoassay in plasma from 15 normal women and 47 women taking oral contraceptives. The plasma apo B concentration in normal women was 0.90 ± 0.10 g/l (mean ±S.D.) whereas the overall value for all women taking contraceptives was 0.69 ± 0.19 g/l. The maximum decrease (p < 0.001) occurred in women investigated within three months after the beginning of the steroid intake, whose mean apo B value was 0.60 ± 0.12 g/l (n = 12); decreases found after 3–24 months of contraception were of lesser magnitude. Apo B decreases were associated with significant decreases (p < 0.01) in total plasma cholesterol, although the latter regained normal values after one year of contraception. Apo B and cholesterol values were in the normal range in women investigated after two years of steroid intake. An inverse trend was observed for plasma triglycerides, which showed a mean increase of 29% (p < 0.01) after three months of steroid intake, and then stayed elevated without significant change with time.     

The effect of Kinesio Taping on postural control in subjects with non-specific chronic low back pain

Purpose

The aim of this study was to investigate the possible alterations in postural control during upright standing in subjects with non-specific chronic low back pain and the effect of Kinesio taping on the postural control.

The effect of the perfusion parameters on the functional characteristics of the thrombocytes

Platelet and plasma monoamine oxidase (MAO) activity was evaluated in two groups of patients at different stages of surgery (before perfusion, at the depth of cooling, height of warming, and 1 h and 24 h after perfusion). Group 1 consisted of 26 patients with acquired heart diseases operated on under artificial circulation and hypothermia (26-29 degrees C), group 2 consisted of 13 patients subjected to reconstructive operations on the aorta under artificial circulation with deep hypothermia (14 degrees C) and circulatory arrest for 50 min. The activity of platelet MAO was decreased in group 1 (by more than 50% during cooling and by 68% during warming and 1 h after perfusion); 24 h after surgery MAO activity increased, but did not reach the initial value. In group 2 the decrease in MAO activity was more expressed, starting from the second switching of the artificial bypass device after circulatory arrest (by almost 50% during cooling, by almost 90% after second switching of artificial circulation, by 94% during warming, and by at least 70% 1 h after perfusion); 24 h after the intervention the platelet MAO activity increased negligibly. MAO activity in the plasma notably increased in both groups during surgery, more so in group 2, which indicates washing out of the enzyme from platelets during artificial circulation because of these cells' damage. These data suggest that platelet injury is a result of their mechanical injury in the bypass circulation and of excessive partial oxygen pressure (400 mm Hg and higher) during perfusion, due to increased oxygen solubility in the plasma at low temperature. This leads to production of excessive active oxygen forms which damage cell membranes and inhibit MAO activity.     

The effect of captopril on blood pressure and angiotensins I, II and III in sodium-depleted dogs: problems associated with the measurement of angiotensin II after inhibition of converting enzyme

1. Changes in arterial blood pressure, blood angiotensin I, plasma angiotensin II and plasma angiotensin III were measured in conscious sodium-depleted dogs after infusion of captopril, an orally active inhibitor of converting enzyme. 2. Angiotensins II and III were measured after chromatography to remove angiotensin I, which increased in concentration after inhibition of converting enzyme and which interfered in the direct assay for angiotensin II. 3. Infusion of captopril at 20, 200, 2000 and 6000 microgram h-1 kg-1, each for 3 h, produced a rapid fall in blood pressure and in concentration of angiotensin II. Angiotensin II was undetectable at 6000 microgram h-1 kg-1 (mean pre-infusion value for all samples was 39 +/- SD 15 pmol/1, n = 14). 4. The percentage fall in blood pressure correlated with the percentage fall in plasma angiotensin II (r = 0.65, P < 0.001). 5. These results suggest that the initial fall in blood pressure may be mediated in part by the suppression of angiotensin II. 6. Blood angiotensin I concentration rose with each rate of infusion of drug to a maximum 16-fold increase at 6000 microgram h-1 kg-1 (26-416 pmol/l). The rise in angiotensin I was inversely related to the fall in angiotensin II (r = 0.68, P < 0.001).     

Responses of the systemic circulation and of the renin-angiotensin-aldosterone system to ketanserin at rest and exercise in normal man

The systemic circulation at rest and during exercise was studied in ten normal male volunteers, after placebo on one occasion and after acute intravenous administration of the serotonergic antagonist ketanserin on another occasion. The effects of ketanserin on the components of the renin-angiotensin-aldosterone system, on plasma catecholamines and on exercise capacity for graded uninterrupted exercise were also investigated. At rest in recumbency rapid intravenous injection of 10 mg of ketanserin, followed by a continuous infusion of 2 mg/h, produced an acute but transient fall in mean intra-arterial pressure of 6 mmHg compared with placebo. After 15 min the mean arterial pressure with ketanserin was within 2 mmHg of the mean pressure with placebo. In the sitting position both at rest and up to 30% of maximal work rate, the mean arterial pressure during ketanserin did not differ from the pressure on placebo. However, at higher levels of physical activity the rise in mean arterial pressure was lower with ketanserin; the pressure achieved with placebo was 7.5 mmHg higher at maximal work rate. Heart rate and cardiac output were significantly higher during ketanserin. When the subjects were lying down and resting, plasma noradrenaline and adrenaline levels, plasma renin activity and angiotensin II concentration were not affected by ketanserin; however, these values were higher in the sitting position both at rest and during exercise. Plasma aldosterone was reduced by ketanserin during exercise and also when the subject was resting in the recumbent position.(ABSTRACT TRUNCATED AT 250 WORDS)     

Low molecular weight hydroxyethyl starch 6% compared to albumin 4% during intentional hemodilution

Intentional normovolemic hemodilution was chosen as the model to compare a 6% low molecular weight hydroxyethyl starch (LMW HES) to 4% albumin. The study ran over the plasma exchange period for 24 h. Nine patients, scheduled for abdominal aortic surgery, were included in each group. After basal measurements, blood was withdrawn and simultaneously replaced by either 4% albumin (Group 1) or 6% LMW HES (Group 2) to achieve a final hematocrit of approximately 30%. Hemodynamic blood oxygen gas and hormonal plasma levels were determined before hemodilution then at 30 min, 1, 2, 3, and 24 h after the end of hemodilution. Basal value for total blood volume was 4377±162 ml in group 1 and 4138±315 ml in group 2. As in both groups the decrease in blood cell volume was exactly compensated by the increase in plasma volume, no significant change in total blood volume (respectively 4432±159 and 4305±267 ml) was observed. Throughout the study, in both groups, no significant change in mean arterial and right atrial pressures was observed. In group 2 (LMW HES), a significant increase of pulmonary capillary wedge pressure was noted 120 min after hemodilution. After hemodilution, despite a significant decrease in arterial oxygen O₂ content, systemic oxygen transport did not significantly vary until 24 h in relation to the increased cardiac index. An increase in O₂ extraction was observed until the 24 h. No significant chagnes either in global O₂ consumption or in lactate concentration were detected. Plasma renin activity fell in both groups while atrial natriuretic factor increased with a peak value at the 2 h. These data suggest that LMW HES as well as 4% albumin was able to maintain at least normovolemia during a 24 h period after intentional hemodilution.     

Plasma colloid osmotic pressure in trauma patients: Direct measurement versus indirect estimates from plasma proteins and solids

The aim of our study was to compare directly measured and calculated plasma colloid osmotic pressure (COP). COP was measured with a membrane colloid osmometer and was calculated using the equations of Landis and Pappenheimer by three methods: from albumin and globulin concentrations, from total protein concentrations, and from plasma solids measured with a refractometer. Eight volunteers (39 measurements) and 28 trauma patients (161 measurements) were studied. We found that COP calculated from albumin and globulin or total protein concentrations systematically underestimated measured COP. In contrast, COP calculated from plasma solids was in better agreement with measured COP. We conclude that calculated estimates of plasma COP may be erroneously low, partly because of therapeutically administered nonprotein colloids. Refractometry measures all plasma solids and is therefore better suited for the rapid assessment of COP. However, coefficients of correlation between measured and calculated COP for these data using published equations were r = .92 at best. In contrast, the new equation we defined allows COP to be calculated from plasma solids and the albumin to globulin ratio and shows a better correlation with measured COP (r = .96). For highest accuracy, a direct measurement is preferable.