Pulse oximetry plethysmographic waveform during changes in blood volume.
Systolic pressure variation (SPV) and its dDown component have been shown to be sensitive factors in estimating intravascular volume in patients undergoing mechanical ventilation. In this study, ventilation-induced changes in pulse oximeter plethysmographic waveform were evaluated after removal and after reinfusion of 10% estimated blood volume. The plethysmographic waveform variation (SPVplet) was measured as the difference between maximal and minimal peaks of waveform during the ventilatory cycle, and expressed as a percentage of the signal amplitude during apnoea. dUp(plet) and dDown(plet) were measured as the distance between the apnoeic plateau and the maximal or minimal plethysmographic systolic waveform, respectively. Intravascular volume was changed by removal of 10% of estimated blood volume and followed by equal volume replacement with Haemaccel. A 10% decrease in blood volume increased SPVplet from mean 17.0 (SD 11.8)% to 31.6 (28.0)% (P = 0.005) and dDown(plet) from 8.7 (5.1)% to 20.5 (12.9)% (P = 0.0005) compared with baseline. Changes in plethysmographic waveform correlated with changes in arterial SPV and dDown (r = 0.85; P = 0.0009). In the absence of invasive arterial pressure monitoring, ventilation-induced waveform variability of the plethysmographic signal measured from pulse oximetry is a useful tool in the detection of mild hypovolaemia. (+info)
Role of pump prime in the etiology and pathogenesis of cardiopulmonary bypass-associated acidosis.
BACKGROUND: The development of metabolic acidosis during cardiopulmonary bypass (CPB) is well recognized but poorly understood. The authors hypothesized that the delivery of pump prime fluids is primarily responsible for its development. Accordingly, acid-base changes induced by the establishment of CPB were studied using two types of priming fluid (Haemaccel, a polygeline solution, and Ringer's Injection vs. Plasmalyte 148) using quantitative biophysical methods. METHODS: A prospective, double-blind, randomized trial was conducted at a tertiary institution with 22 patients undergoing CPB for coronary artery bypass surgery. Sampling of arterial blood was performed at three time intervals: before CPB (t1), 2 min after initiation of CPB at full flows (t2), and at the end of the case (t3). Measurements of Na+, K+, Mg2+, Cl-, HCO3-, phosphate, Ca2+, albumin, lactate, and arterial blood gases at each collection point were performed. Results were analyzed in a quantitative manner. RESULTS: Immediately on delivery of pump prime fluids, all patients developed a metabolic acidosis (base excess: 0. 95 mEq/l (t1) to -3.65 mEq/l (t2) (P < 0.001) for Haemaccel-Ringer's and 1.17 mEq/l (t1) to -3.20 mEq/l (t2). The decrease in base excess was the same for both primes (-4.60 vs. -4.37; not significant). However, the mechanism of metabolic acidosis was different. With the Haemaccel-Ringer's prime, the metabolic acidosis was hyperchloremic (Delta Cl-, +9.50 mEq/l; confidence interval, 7.00-11.50). With Plasmalyte 148, the acidosis was induced by an increase in unmeasured anions, most probably acetate and gluconate. The resolution of these two processes was different because the excretion of chloride was slower than that of the unmeasured anions (Delta base excess from t1 to t3 = -1.60 for Haemaccel-Ringer's vs. +1.15 for Plasmalyte 148; P = 0.0062). CONCLUSIONS: Cardiopulmonary bypass-induced metabolic acidosis appears to be iatrogenic in nature and derived from the effect of pump prime fluid on acid-base balance. The extent of such acidosis and its duration varies according to the type of pump prime. (+info)
Carrier solutions for low-level intravenous insulin infusion.
In the use of low-level intravenous insulin infusion for treating diabetic hyperglycaemia and ketoacidosis adsorption of insulin to containers or plastic infusion apparatus results in significant losses of 60-80% of insulin in dilute physiological saline solution (40 U/l). It is therefore necessary to add protein to the carrier solution to minimize losses and maintain a constant delivery rate. Recovery studies showed that 3.5% w/v polygeline solution (polymer of degraded gelatin) was a suitable medium for this purpose, offering some advantages over human serum albumin. A minimum concentration of 0.5% polygeline was required to ensure adequate delivery of insulin to the patient. (+info)
Randomized evaluation of fluid resuscitation with crystalloid (saline) and colloid (polymer from degraded gelatin in saline) in pediatric septic shock.
OBJECTIVE: To compare the efficacy of crystalloid (Normal saline) and colloid (polymer from degraded Gelatin in saline Haemaccel) intravenous fluid in restoration of circulating volume in children with septic shock. DESIGN: Prospective, randomized, open-label trial. SETTING: Pediatric Emergency and Intensive Care Unit of a tertiary care referral and teaching hospital. SUBJECTS AND INCLUSION CRITERIA: Sixty patients, between 1 month to 12 years of age, with septic shock, without clinical evidence of organ failure at admission or underlying immunodeficiency. INTERVENTION: Resuscitation with normal saline or polymer from degraded gelatin (Haemaccel) in the boluses rate of 20 mL/kg till hemodynamic stabilization or if central venous pressure (CVP) exceeded 10 mmHg (fluid requirement beyond 40 mL/kg guided by BP and CVP). METHODS: Hemodynamic parameters (heart rate, capillary filling time, pulse volume, and blood pressure) were recorded before and during resuscitation, and then 2 hourly for 12 hours. Central venous pressure line was placed within first hour, soon after starting fluids. Estimation of plasma volume and body water was done at the end of first hour of fluid resuscitation. OUTCOME MEASURES: Hemodynamic stabilization (heart rate, capillary refill time, systolic BP in normal range), plasma volume at the end of fluid resuscitation and incidence of organ dysfunction. RESULTS: 31 patients were randomized to normal saline and 29 to gelatin polymer. Both the groups were similar with respect to age, gender, primary diagnosis, initial hemodynamic parameters and PRISM score. Pneumonia (n = 22; 36%), gut-associated sepsis (n = 13), and dengue hemorrhagic fever (n = 11) were the common primary diagnosis. Initial hemodynamic stabilization was achieved in all. The mean (SD plasma volume (saline--53.4 (2.0 mL/kg, gelatin polymer--53.2 (1.9 mL/kg), extracellular fluid volume, total body water and interstitial fluid volume at the end of first hour of resuscitation were similar. The requirement of inotropes, incidence of organ dysfunction and case fatality rate (Saline--29%, gelatin polymer--31%), were similar in two groups. CONCLUSION: Both normal saline and gelatin polymer solution were equally effective as resuscitation fluid with respect to restoration of plasma volume and hemodynamic stability. Normal saline upto 110 mL/kg, and gelatin polymer solution upto 70 mL/kg may be required in first hour for successful fluid resuscitation of septic shock in children. (+info)
Does calcium cause the different effects of Gelofusine and Haemaccel on coagulation?
BACKGROUND: Gelofusine (which does not contain calcium) has a greater effect on coagulation than Haemaccel (which contains 6.25 mmol/l of calcium). This in vitro study was performed to assess whether calcium might be the cause of the different effects on coagulation. METHODS: Three solutions were compared; (a) Gelofusine, (b) Gelofusine with calcium added to 6.25 mmol/l, and (c) Haemaccel. Thromboelastography (Sonoclot) was used to examine whole blood coagulation, with time to peak clot weight as the primary outcome measure. RESULTS: There was no significant difference between the Gelofusine containing solutions. Both Gelofusine solutions gave a greater impairment of coagulation than the Haemaccel solution. CONCLUSIONS: The different effect of Gelofusine on coagulation compared with Haemaccel does not seem to be related to the different calcium contents of the solutions. (+info)
Influence of acute plasma volume expansion on VO2 kinetics, VO2 peak, and performance during high-intensity cycle exercise.
The purpose of this study was to examine the influence of acute plasma volume expansion (APVE) on oxygen uptake (V(O2)) kinetics, V(O2peak), and time to exhaustion during severe-intensity exercise. Eight recreationally active men performed "step" cycle ergometer exercise tests at a work rate requiring 70% of the difference between the gas-exchange threshold and V(O2max) on three occasions: twice as a "control" (Con) and once after intravenous infusion of a plasma volume expander (Gelofusine; 7 ml/kg body mass). Pulmonary gas exchange was measured breath by breath. APVE resulted in a significant reduction in hemoglobin concentration (preinfusion: 16.0 +/- 1.0 vs. postinfusion: 14.7 +/- 0.8 g/dl; P < 0.001) and hematocrit (preinfusion: 44 +/- 2 vs. postinfusion: 41 +/- 3%; P < 0.01). Despite this reduction in arterial O(2) content, APVE had no effect on V(O2) kinetics (phase II time constant, Con: 33 +/- 15 vs. APVE: 34 +/- 12 s; P = 0.74), and actually resulted in an increased V(O2peak) (Con: 3.90 +/- 0.56 vs. APVE: 4.12 +/- 0.55 l/min; P = 0.006) and time to exhaustion (Con: 365 +/- 58 vs. APVE: 424 +/- 64 s; P = 0.04). The maximum O(2) pulse was also enhanced by the treatment (Con: 21.3 +/- 3.4 vs. APVE: 22.7 +/- 3.4 ml/beat; P = 0.04). In conclusion, APVE does not alter V(O2) kinetics but enhances V(O2peak) and exercise tolerance during high-intensity cycle exercise in young recreationally active subjects. (+info)
Impairment of coagulation by commonly used resuscitation fluids in human volunteers.
BACKGROUND: This study compared the effects of two commonly used resuscitation fluids on whole blood coagulation. METHODS: 1000 ml of two resuscitation fluids each (saline and Gelofusine) were given to eight volunteers in a crossover design with a 2-week washout period. The effect on whole blood coagulation was assessed using the Sonoclot analyzer, a conventional coagulation screen and coagulation markers. RESULTS: No significant effect was found on whole blood coagulation by giving saline (time to peak clot increased by a mean of 106 s; (95% confidence interval (CI) -140 to 354), whereas Gelofusine delayed the time to peak by a mean of 845 s (95% CI 435 to 1255). By contrast, there was no change in the conventional coagulation screen with either fluid. CONCLUSION: It was concluded that some resuscitation fluids have an effect on clot formation that is not shown by the conventional coagulation screen, but is disclosed only if the whole coagulation process is studied. (+info)
Severe anaphylaxis to Gelofusine during a transthoracic echo bubble study.
We describe a severe anaphylactic reaction to Gelofusin, used as part of a transthoracic echo study on a middle-aged woman who had suffered a prior cerebral event. (+info)