| 1. |
- Brauer, Kirk I, et al.
(author)
-
Hypoproteinemia does not alter plasma volume expansion in response to a 0.9% saline bolus in awake sheep
- 2010
-
In: CRITICAL CARE MEDICINE. - : Williams and Wilkins. - 0090-3493 .- 1530-0293. ; 38:10, s. 2011-2015
-
Journal article (peer-reviewed)abstract
- Objective: To test the hypothesis that hypoproteinemia reduces plasma volume expansion produced by a bolus of crystalloid solution given to awake sheep. Design: Prospective and observational. Setting: Laboratory. Subjects: Five female merino sheep (n = 5) weighing 37 +/- 3 kg were anesthetized. Interventions: Each animal was subjected to a 5-day test period: day 1: 50 mL/min 0.9% saline infusion over 20 mins. Days 2-4: daily plasmapheresis and replacement of the shed plasma with 6 L of 0.9% saline were performed in increments. Measurements and Main Results: Fractional plasma volume expansion after rapid infusion of saline on days 1 and 5 was calculated from changes in hemoglobin concentration. There was a significant reduction in total plasma protein concentration after plasmapheresis (p andlt; .05). Colloid osmotic pressures were also significantly lowered (p andlt; .05). A crystalloid infusion of 0.9% saline did not alter any of these values compared with baseline. The hemodynamic measurements did not show significant differences between the experiments. The plasma volume expansion reached approximately 20% at the end of infusion and stayed at 10-15% during the experiments. No difference was found in plasma volume expansion produced by a bolus of 50 mL/min of 0.9% in the hypoproteinemic state when compared with the euproteinemic state (p = .61). No difference in cumulative urinary output was found between the two states. Conclusions: In contrast to our hypothesis, severe acute hypoproteinemia does not reduce plasma volume expansion in response to 50 mL/min 0.9% saline infusion in nonspleenectomized sheep when compared with the resultant plasma volume expansion after a 50 mL/min of 0.9% infusion in the euproteinemic state.
|
|
| 2. |
- Hahn, Robert G, et al.
(author)
-
Isoflurane inhibits compensatory intravascular volume expansion after hemorrhage in sheep
- 2006
-
In: Anesthesia and Analgesia. - : Lippincott Williams & Wilkins. - 0003-2999 .- 1526-7598. ; 103:2, s. 350-358
-
Journal article (peer-reviewed)abstract
- After hemorrhage, blood volume is partially restored by transcapillary refill, a process of spontaneous compensatory intravascular volume expansion that we hypothesized would be inhibited by anesthesia. Six chronically instrumented sheep were subjected to four randomly ordered experiments while conscious or during anesthesia with isoflurane. After plasma volume measurement (indocyanine green), 15% or 45% of the blood volume was withdrawn. To quantify transcapillary refill, mass balance and kinetic calculations utilized repeated measurements of hemoglobin concentration, assuming that transcapillary refill would dilute hemoglobin concentration. After 15% hemorrhage, mean arterial blood pressure remained stable in both conscious and isoflurane-anesthetized sheep (normotensive hemorrhage) but decreased after 45% hemorrhage (hypotensive hemorrhage). After either normotensive or hypotensive hemorrhage, transcapillary refill occurred more rapidly during the first 40 min than during the next 140 min (P < 0.001). In conscious sheep, at 180 min, 57% and 42% of the bled volume had been restored after normotensive and hypotensive hemorrhage, respectively, in contrast to only 13% and 27% (P < 0.001) in isoflurane-anesthetized sheep. A novel kinetic model implicated hemodynamic factors in rapid, early transcapillary refill and decreased plasma oncotic pressure in subsequent slower filling. We conclude that isoflurane inhibits transcapillary refill after both normotensive and hypotensive hemorrhage in sheep.
|
|
| 3. |
- Marion, E K, et al.
(author)
-
Spinal blocks with and without morphine in women undergoing hysterectomies : a randomized study
- 2010
-
In: Sri Lankan Journal of Anaesthesiology. - : Sri Lanka Journals Online (JOL). - 1391-8834 .- 2279-1965. ; 18:1, s. 23-28
-
Journal article (peer-reviewed)abstract
- Objective: To study whether a group of patients going through abdominal hysterectomies under general anesthesia could reduce their time of discharge and consumption of parenteral opioids by adding morphine to an intrathecal block. Methods: Sixty seven healthy women, undergoing abdominal hysterectomies. Patients had general anesthesia in combination with spinal blocks. Randomization between intrathecal blocks with morphine (group 1) and without morphine (group 2), in combination with either postoperative intermittent (group 1) or patient controlled analgesia (group 2). Results: The median time to discharge in group 1 was 53 hours and in group two 69 hours. Time of discharge was not statistically significant (p = 0.51). The patients in group 2 had significantly higher visual analogue scores for pain postoperatively. More postoperative opioids were also consumed in that group (p Conclusion: In summary, we conclude that intrathecal block with morphine in combination with postoperative nurse administered opioids did not show a difference in time to discharge compared to intratechal block without morphine in combination with PCA. However, there was a significant reduction in the level of pain and nausea as well as consumption of postoperative opioids. Based on the questionnaire, significantly more patients suffered from major nausea in the group without intrathecal morphine.
|
|
| 4. |
- Norberg, Åke, et al.
(author)
-
Population volume kinetics predicts retention of 0.9% saline infused in awake and isoflurane-anesthetized volunteers
- 2007
-
In: Anesthesiology. - : Lippincott Williams & Wilkins. - 0003-3022 .- 1528-1175. ; 107:1, s. 24-32
-
Journal article (peer-reviewed)abstract
- BACKGROUND: In previous work, extravascular expansion was observed to be enhanced by isoflurane anesthesia in sheep when a crystalloid bolus was administered. The aim of the current study was to further elaborate these investigations to humans and to explore the use of population kinetics in the analysis of fluid shifts.METHODS: Eleven healthy volunteers participated in two experiments each, either awake or isoflurane anesthetized, during which they received 25 ml/kg saline, 0.9%, intravenously over 20 min. Plasma dilution data were derived from repeated sampling of hemoglobin concentration, and population pharmacokinetic analysis was conducted using the WinNonMix 2.0.1 software (Pharsight Corporation, Mountain View, CA). Plasma hormones were measured, and hemodynamic values were monitored.RESULTS: Fluid infusion during isoflurane anesthesia was followed by a higher cardiac output, lower arterial pressure, and lower urinary excretion as compared with the awake protocol (P < 0.05). Albumin dilution was greater than hemoglobin concentration-derived plasma dilution, which indicates a transcapillary leak of albumin. A two-compartment model with an isoflurane-depressed, intercompartmental distribution parameter predicted that more than 50% of the infused volume was retained in the peripheral compartment at 180 min in both protocols. Isoflurane markedly increased the plasma levels of renin and aldosterone, whereas vasopressin was mostly unchanged.CONCLUSION: Fluid retention after rapid infusion of 0.9% saline was prominent in both awake and isoflurane-anesthetized subjects. Altered kinetics of infused 0.9% saline during isoflurane anesthesia was expressed as reduced clearance and a slower distribution, resulting in a small but significant increase in fluid accumulation in the body fluid compartments. These changes may be due to the associated decreasing of mean arterial pressure and increased release of renin and aldosterone.
|
|
| 5. |
- Norberg, Åke, et al.
(author)
-
Volume turnover kinetics of fluid shifts after hemorrhage, fluid infusion, and the combination of hemorrhage and fluid infusion in sheep
- 2005
-
In: Anesthesiology. - : Lippincott Williams & Wilkins. - 0003-3022 .- 1528-1175. ; 102:5, s. 985-994
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Hemorrhage is commonly treated with intravenous infusion of crystalloids. However, the dynamics of fluid shifts between body fluid spaces are not completely known, causing contradictory recommendations regarding timing and volume of fluid infusions. The authors have developed a turnover model that characterizes these fluid shifts.METHODS: Conscious, chronically instrumented sheep (n = 12) were randomly assigned to three protocol groups: infusion of 25 ml/kg of 0.9% saline over 20 min (infusion only), hemorrhage of 300 ml (7.8 +/- 1.1 ml/kg) over 5 min (hemorrhage only), and hemorrhage of 300 ml over 5 min followed by infusion as noted above (hemorrhage plus infusion). A two-compartment volume turnover kinetic model containing seven model parameters was fitted to data obtained by repeated sampling of hemoglobin concentration and urinary excretion.RESULTS: The volume turnover model successfully predicted fluid shifts. Mean baseline volumes of the central and tissue compartments were 1799 +/- 1276 ml and 7653 +/- 5478 ml, respectively. Immediate fluid infusion failed to prevent hemorrhage-induced depression of cardiac output and diuresis. The model suggested that volume recruitment to the central compartment after hemorrhage was primarily achieved by mechanisms other than volume equilibration between the two model compartments.CONCLUSION: Volume turnover kinetics is a promising tool for explaining fluid shifts between body compartments after perturbations such as hemorrhage and intravenous fluid infusions. The pronounced inhibition of renal output after hemorrhage prevailed regardless of fluid infusion and caused fluid retention, which expanded the tissue compartment.
|
|
| 6. |
- Nyberg, Joakim, 1978-, et al.
(author)
-
RETRACTED: Population Kinetics of 0.9% Saline Distribution in Hemorrhaged Awake and Isoflurane-anesthetized Volunteers
- 2019
-
In: Anesthesiology. - : Ovid Technologies (Wolters Kluwer Health). - 0003-3022 .- 1528-1175. ; 131:3, s. 501-511
-
Journal article (peer-reviewed)abstract
- Background: Population-based, pharmacokinetic modeling can be used to describe variability in fluid distribution and dilution between individuals and across populations. The authors hypothesized that dilution produced by crystalloid infusion after hemorrhage would be larger in anesthetized than in awake subjects and that population kinetic modeling would identify differences in covariates. Methods: Twelve healthy volunteers, seven females and five males, mean age 28 +/- 4.3 yr, underwent a randomized crossover study. Each subject participated in two separate sessions, separated by four weeks, in which they were assigned to an awake or an anesthetized arm. After a baseline period, hemorrhage (7 ml/kg during 20 min) was induced, immediately followed by a 25 ml/kg infusion during 20 min of 0.9% saline. Hemoglobin concentrations, sampled every 5 min for 60 min then every 10 min for an additional 120 min, were used for population kinetic modeling. Covariates, including body weight, sex, and study arm (awake or anesthetized), were tested in the model building. The change in dilution was studied by analyzing area under the curve and maximum plasma dilution. Results: Anesthetized subjects had larger plasma dilution than awake subjects. The analysis showed that females increased area under the curve and maximum plasma dilution by 17% (with 95% CI, 1.08 to 1.38 and 1.07 to 1.39) compared with men, and study arm (anesthetized increased area under the curve by 99% [0.88 to 2.45] and maximum plasma dilution by 35% [0.71 to 1.63]) impacted the plasma dilution whereas a 10-kg increase of body weight resulted in a small change (less than1% [0.93 to 1.20]) in area under the curve and maximum plasma dilution. Mean arterial pressure was lower in subjects while anesthetized (P < 0.001). Conclusions: In awake and anesthetized subjects subjected to controlled hemorrhage, plasma dilution increased with anesthesia, female sex, and lower body weight. Neither study arm nor body weight impact on area under the curve or maximum plasma dilution were statistically significant and therefore no effect can be established.
|
|
| 7. |
- Svensen, Christer H, et al.
(author)
-
Arteriovenous differences in plasma dilution and the distribution kinetics of lactated ringer's solution
- 2009
-
In: Anesthesia and Analgesia. - : Lippincott Williams & Wilkins. - 0003-2999 .- 1526-7598. ; 108:1, s. 128-133
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Conventional concept suggests that infused crystalloid fluid is first distributed in the plasma volume and then, since the capillary permeability for fluid is very high, almost instantly equilibrates with the extracellular fluid space. We challenge whether this view is consistent with findings based on volume kinetic analysis.METHODS: Fifteen volunteers received an IV infusion of 15 mL/kg of lactated Ringer's solution during 10 min. Simultaneous arterial and venous blood hemoglobin (Hgb) samples were obtained and Hgb concentrations measured. The arteriovenous (AV) difference in Hgb dilution in the forearm was determined and a volume kinetic model was fitted to the series of Hgb concentrations in arterial and venous blood.RESULTS: The AV difference in plasma dilution was only positive during the infusion and for 2.5 min thereafter, which represents the period of net flow of fluid from plasma to tissue. Kinetic analysis showed that volume expansion of the peripheral fluid space began to decrease 14 min (arterial blood) and 20 min (venous blood) after the infusion ended. Distribution of lactated Ringer's solution apparently occurs much faster in the forearm than in the body as a whole. Therefore, the AV difference in the arm does not accurately reflect the distribution of Ringer's solutions or whole-body changes in plasma volume.CONCLUSIONS: The relatively slow whole-body distribution of lactated Ringer's solution, which boosts the plasma volume expansion during and for up to 30 min after an infusion, is probably governed by a joint effect of capillary permeability and differences in tissue perfusion between body regions.
|
|
| 8. |
- Svensén, Christer H, et al.
(author)
-
Intravascular fluid administration and hemodynamic performance during open abdominal surgery
- 2006
-
In: Anesthesia and Analgesia. - : Lippincott Williams & Wilkins. - 0003-2999 .- 1526-7598. ; 103:3, s. 671-676
-
Journal article (peer-reviewed)abstract
- We studied whether central hemodynamics measured by a pulmonary artery catheter can serve as a pharmacodynamic expression of fluid therapy in 10 patients undergoing open abdominal surgery. We examined how closely hemodynamic variables follow plasma dilution, which is an index of plasma volume expansion, during and after an IV infusion of 25 mL/kg of lactated Ringer's solution over 45 min. Pulmonary artery wedge pressure and central venous pressure responded to IV fluid with an increase that correlated with accompanying plasma dilution. Six of 10 patients showed a decrease in cardiac output that was probably secondary to an increase in peripheral vascular resistance (nonresponders), whereas the rest increased cardiac output (responders). Volume kinetic analysis suggested that 54% of the infused fluid resided in the central fluid space at the end of the infusion and 25% at the end of the study in the responders compared with 25% and 3%, respectively, in nonresponders. In conclusion, half of the patients undergoing open abdominal surgery responded to crystalloid fluid with a decrease in cardiac output. Pulmonary artery wedge pressure and central venous pressure responded more consistently to different degrees of plasma dilution, which can be simulated for various fluid regimens using volume kinetics.
|
|
| 9. |
- Zeng, Ruifeng, et al.
(author)
-
Can noninvasive hemoglobin measurement reduce the need for preoperative venipuncture in pediatric outpatient surgery?
- 2017
-
In: Pediatric Anaesthesia. - : WILEY. - 1155-5645 .- 1460-9592. ; 27:11, s. 1131-1135
-
Journal article (peer-reviewed)abstract
- Background: Noninvasive measurements of hemoglobin in the pediatric perioperative setting could be helpful to avoid venipunctures in children. The present study aims to evaluate this by using a noninvasive device for hemoglobin determination. We compared noninvasively obtained hemoglobin with laboratory hemoglobin concentrations in children during their preoperative assessment.Methods: In an observational study, 122 nonanemic children (age 4.21.6years) who were scheduled to undergo different surgical procedures under general anesthesia were included. In their preoperative preparations, single invasive blood samples for laboratory hemoglobin concentrations were routinely taken following hospital policy and compared to simultaneous noninvasive determinations of hemoglobin. A preoperative invasive value 9g/dL would have caused cancelation of surgery and implied further investigations.Results: A Bland-Altman plot showed that the average difference between noninvasively obtained hemoglobin and laboratory hemoglobin concentration was -0.44g/dL (bias) with a standard deviation of the mean bias of 1.04g/dL. A hemoglobin error grid showed that the noninvasive device could identify almost all invasive hemoglobin values >9g/dL. In total, there were 4 false-positive values where noninvasively obtained hemoglobin observations were below while the paired invasive values were above 9g/dL.Conclusion: The data in this pediatric setting suggest that the device may eliminate the need for venipuncture in nonanemic children.
|
|
