Circulatory Effects of Hypoxia, Acute Normovolemic Hemodilution, and Their Combination in Anesthetized Pigs

Schou, Henning; Perez-de-Sa, Valeria; Sigurdardottir, Maria; Roscher, Roger; Jonmarker, Christer; Werner, Olof

doi:10.1097/00000542-199606000-00021

Cited by 30 publications

(20 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The critical oxygen delivery, below which VO 2 becomes supply dependent, has not been reported in rabbits. In multiple species, however, the onset of supply dependence is associated with reductions of mixed venous saturations to the range of 30 -50% (1,8,36,60), well below the lowest venous saturation of 64% observed in the current study. The paired differences in Sv O 2 between the two groups (high rate, low PEEP vs. low rate, high PEEP), therefore, support the cardiac output data measured by pulse contour analysis.…”

Section: Discussioncontrasting

confidence: 65%

Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

Syring

Otto²,

Spivack³

et al. 2007

Journal of Applied Physiology

View full text Add to dashboard Cite

Cyclical recruitment of atelectasis with each breath is thought to contribute to ventilator-associated lung injury. Extrinsic positive end-expiratory pressure (PEEPe) can maintain alveolar recruitment at end exhalation, but PEEPe depresses cardiac output and increases overdistension. Short exhalation times can also maintain end-expiratory recruitment, but if the mechanism of this recruitment is generation of intrinsic PEEP (PEEPi), there would be little advantage compared with PEEPe. In seven New Zealand White rabbits, we compared recruitment from increased respiratory rate (RR) to recruitment from increased PEEPe after saline lavage. Rabbits were ventilated in pressure control mode with a fraction of inspired O(2) (Fi(O(2))) of 1.0, inspiratory-to-expiratory ratio of 2:1, and plateau pressure of 28 cmH(2)O, and either 1) high RR (24) and low PEEPe (3.5) or 2) low RR (7) and high PEEPe (14). We assessed cyclical lung recruitment with a fast arterial Po(2) probe, and we assessed average recruitment with blood gas data. We measured PEEPi, cardiac output, and mixed venous saturation at each ventilator setting. Recruitment achieved by increased RR and short exhalation time was nearly equivalent to recruitment achieved by increased PEEPe. The short exhalation time at increased RR, however, did not generate PEEPi. Cardiac output was increased on average 13% in the high RR group compared with the high PEEPe group (P < 0.001), and mixed venous saturation was consistently greater in the high RR group (P < 0.001). Prevention of end-expiratory derecruitment without increased end-expiratory pressure suggests that another mechanism, distinct from intrinsic PEEP, plays a role in the dynamic behavior of atelectasis.

show abstract

Section: Discussioncontrasting

confidence: 65%

Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

Syring

Otto²,

Spivack³

et al. 2007

Journal of Applied Physiology

View full text Add to dashboard Cite

show abstract

“…Schweine eine schwerste Hypoxämie (p a O 2 25-35 mmHg) in identischem Maße -unabhängig davon, ob die Tiere zuvor auf einen HKT von 11 (0,11) hämodiluiert worden waren oder nicht [91]. Während bei Patienten mit schwerster COPD durch die Transfusion von Hb 8,7 g/dl (5,40 mmol/ l) auf Hb 12 g/dl (7,45 mmol/l) und höher eine deutliche Beschleunigung des Weaningprozesses von der maschinellen Beatmung nachgewiesen werden konnte [90], war die Dauer des Weanings in einer anderen Untersuchung unabhängig davon, ob eine restriktive [Ziel-Hb 7-9 g/dl (4,34-5,59 mmol/l)] oder eine liberale [Ziel-Hb 10-12 g/dl (6,21-7,45 mmol/l)] Transfusionsstrategie zum Zuge kam [42].…”

Section: Myokardperfusion Und -Funktionunclassified

Perioperative Anämietoleranz

Häbler

Meier²,

Pape³

et al. 2006

Anaesthesist

View full text Add to dashboard Cite

The expected cost explosion in transfusion medicine (increasing imbalance between donors and potential recipients, treatment of transfusion-associated complications) increases the socio-economic significance of specific institutional transfusion programs. In this context the estimated use of the patient's physiologic tolerance to anemia enables 1) the tolerance of larger blood losses (loss of "diluted blood"), 2) the onset of transfusion to the time after surgical control of bleeding to be delayed and 3) the perioperative collection of autologous red blood cells. The present review article summarizes the mechanisms, influencing factors and limits of this natural tolerance to anemia and deduces the indication for perioperative red blood cell transfusion. Under strictly controlled conditions (anesthesia, normovolemia, complete muscular relaxation, hyperoxemia, mild hypothermia) extremely low hemoglobin concentrations [Hb <3 g/dl (<1.86 mmol/l)] are tolerated without transfusion by individuals with no cardiopulmonary disease. In the clinical routine these situations are limited to borderline situations e.g. unexpected massive blood losses in Jehovah's Witnesses or unexpected shortcomings in blood supply. The current recommendations coincide to the effect that perioperative red blood cell transfusion 1) is unnecessary up to a Hb concentration of 10 g/dl (6.21 mmol/l) even in older patients with cardiopulmonary comorbidity and 2) is only recommended in cases of Hb <6 g/dl (<3.72 mmol/l) in otherwise healthy subjects including pregnant women and children. Critically ill patients with multiple trauma and sepsis do not seem to benefit from transfusions up to Hb concentrations >9 g/dl (>5.59 mmol/l). In cases of massive hemorrhaging and diffuse bleeding disorders the maintenance of a Hb concentration of 10 g/dl (6.21 mmol/l) seems to contribute to stabilization of coagulation.

show abstract

“…On one hand, AIHinduced lowering of blood viscosity is expected to facilitate microcirculatory blood flow through collateral and stenotic vessels as well as at the margin of ischemic tissue areas (16,17). On the other hand, excessive reduction of the oxygen-carrying capacity coupled with an impaired ventricular function might result in worsening of myocardial ischemia and ultimately heart failure (18).…”

mentioning

confidence: 99%

Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Licker

Mariéthoz²,

Costa³

et al. 2005

Critical Care Medicine

View full text Add to dashboard Cite

show abstract

Circulatory Effects of Hypoxia, Acute Normovolemic Hemodilution, and Their Combination in Anesthetized Pigs

Abstract: Systemic and myocardial lactate production occurred at similar systemic oxygen delivery rates in hemodiluted and nonhemodiluted animals. Mixed venous oxygen saturation may be a less reliable indicator of inadequate oxygen delivery during hemodilution.

Cited by 30 publications

References 32 publications

Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury

Perioperative Anämietoleranz

Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Contact Info

Product

Resources

About