12 Sep 12

Perioperative morbidity: lessons from recent clinical trials

Posted in Anesthesia, Early goal directed therapy, Fluid management at 3:31 by Laci

By R Thiele, J Huffmyer, J Raphael, Jacob

Curr Opin Crit Care 2012;18:358-365

To identify the recent literature supporting the ability of anesthesiologists to impact morbidity and mortality outside of the immediate intraoperative period.

Recent findings
Hemodynamic management designed to optimize cardiac output and stroke volume can significantly lower the risk of perioperative morbidity, and, in some cases, mortality. The implications of the POISE trial, which upended the previously accumulating data in support of indiscriminate perioperative β-blockade by demonstrating worsened outcomes, were supported by high-quality, propensity-matched, prospectively collected data. Data supporting the safety of colloid use has been threatened by the retraction of 88 publications of a single author, as well as prospective, nonrandomized data, suggesting increased renal morbidity in critically ill patients receiving synthetic colloids. Large datasets continue to suggest an association between red blood cell transfusion and mortality. Analysis of the operating room strongly implicates anesthesia providers as a potential mechanism for bacterial contamination.

Summary
Anesthesiologists should consider implication of goal-directed therapy in high-risk surgical patients, adhere to the American College of Cardiology/American Heart Association guidelines with regard to perioperative β-blockade, critically assess the data to support their choice of synthetic colloids over crystalloids, explore all possible strategies for avoiding perioperative transfusion, and be cognizant of their potential contribution to perioperative infectious morbidity.

16 Apr 09

Crystalloids versus colloids for goal-directed fluid therapy in major surgery

Posted in Early goal directed therapy, Fluid management at 0:57 by Laci

By L B Hiltebrand, O Kimberger, M Arnberger, S Brandt, A Kurz and G H Sigrudsson

Critical Care 2009, 13:R40

Perioperative hypovolemia arises frequently and contributes to intestinal hypoperfusion and subsequent postoperative complications. Goal-directed fluid therapy (GDT) might reduce these complications. The aim of this study was to compare the effects of goal-directed administration of crystalloids and colloids on distribution of systemic, hepato-splanchnic and microcirculatory (small intestine) blood flow after major abdominal surgery in a clinically relevant pig model.

Methods
Twenty-seven pigs were anesthetized, mechanically ventilated and underwent open laparotomy. They were randomly assigned to one of the three following treatment groups: the restricted Ringer’s lactate group (R-RL, n=9) received 3 ml.kg-1.h-1 RL; the goal-directed RL group (GD-RL, n=9) received 3 ml.kg-1.h-1 RL and intermittent boluses of 250 ml RL and the goal-directed colloid group (GD-C, n=9) received 3 ml.kg-1.h-1 RL and boluses of 250 ml 6% hydroxyethyl starch (130/0.4). The two latter groups received a bolus infusion when mixed venous oxygen saturation (SvO2) was below 60% (lock out time 30 minutes). Regional blood flow was measured in the superior mesenteric artery and the celiac trunk. In the small bowel, microcirculatory blood flow was measured using laser Doppler flowmetry. Intestinal tissue oxygen tension was measured with intramural Clark-type electrodes.

Results
After 4 hours of treatment, arterial blood pressure, cardiac output, mesenteric artery flow and mixed oxygen saturation were significantly higher in groups GD-C and GD-RL than in group R-RL. Microcirculatory flow in the intestinal mucosa increased by 50% in GD-C but remained unchanged in the other two groups. Likewise, tissue oxygen tension in the intestine increased by 30% in GD-C but remained unchanged in GD-RL and decreased by 18% in the R-RL group. Mesenteric venous glucose concentrations were higher and lactate levels lower in group GD-C compared with the two crystalloid groups.

Conclusions
Goal-directed colloid administration markedly increased microcirculatory blood flow in the small intestine and intestinal tissue oxygen tension after abdominal surgery. In contrast, goal-directed crystalloid and restricted crystalloid administrations had no such effects. Additionally, mesenteric venous glucose and lactate concentrations suggest that intestinal cellular substrate levels were higher in the colloid-treated than in the crystalloid-treated animals. These results support the notion that perioperative goal-directed therapy with colloids might be beneficial during major abdominal surgery.

23 Dec 08

Central venous-to-arterial carbon dioxide difference: an additional target for goal-directed therapy in septic shock?

Posted in Early goal directed therapy, ScvO2, Sepsis at 0:30 by Laci

By F Vallet, B Vallet, O Mathe, J Parraguette, A Mari et al

Intensive Care Med 2008:34;2218-2225

To test the hypothesis that, in resuscitated septic shock patients, central venous-to-arterial carbon dioxide difference [P(cv-a)CO2] may serve as a global index of tissue perfusion when the central venous oxygen saturation (ScvO2) goal value has already been reached.

Design
Prospective observational study.

Setting
A 22-bed intensive care unit (ICU).

Patients
After early resuscitation in the emergency unit, 50 consecutive septic shock patients with ScvO2 > 70% were included immediately after their admission into the ICU (T0). Patients were separated in Low P(cv-a)CO2 group (Low gap; n = 26) and High P(cv-a)CO2 group (High gap; n = 24) according to a threshold of 6 mmHg at T0.

Measurements
Measurements were performed every 6 h over 12 h (T0, T6, T12).

Results
At T0, there was a significant difference between Low gap patients and High gap patients for cardiac index (CI) (4.3 ± 1.6 vs. 2.7 ± 0.8 l/min/m≤, P < 0.0001) but not for ScvO2 values (78 ± 5 vs. 75 ± 5%, P = 0.07). From T0 to T12, the clearance of lactate was significantly larger for the Low gap group than for the High gap group (P < 0.05) as well as the decrease of SOFA score at T24 (P < 0.01). At T0, T6 and T12, CI and P(cv-a)CO2 values were inversely correlated (P < 0.0001).

Conclusion
In ICU-resuscitated patients, targeting only ScvO2 may not be sufficient to guide therapy. When the 70% ScvO2 goal-value is reached, the presence of a P(cv-a)CO2 larger than 6 mmHg might be a useful tool to identify patients who still remain inadequately resuscitated.

18 Dec 08

ACCM/PALS haemodynamic support guidelines for paediatric septic shock: an outcomes comparison with and without monitoring central venous oxygen saturation

Posted in Early goal directed therapy, ScvO2, Sepsis at 14:22 by Laci

By C F de Oliveira1, D S  de Oliveira1, A F C Gottschald, J D G Moura1, G A Costa1, A C Ventura et al

Intensive Care Med 2008:34;1065-1075

The ACCM/PALS guidelines address early correction of paediatric septic shock using conventional measures. In the evolution of these recommendations, indirect measures of the balance between systemic oxygen delivery and demands using central venous or superior vena cava oxygen saturation (ScvO2>=70%) in a goal-directed approach have been added. However, while these additional goal-directed endpoints are based on evidence-based adult studies, the extrapolation to the paediatric patient remains unvalidated.

Objective
The purpose of this study was to compare treatment according to ACCM/PALS guidelines, performed with and without ScvO2 goal-directed therapy, on the morbidity and mortality rate of children with severe sepsis and septic shock.

Design, participants and interventions
Children and adolescents with severe sepsis or fluid-refractory septic shock were randomly assigned to ACCM/PALS with or without ScvO2 goal-directed resuscitation.

Measurements
Twenty-eight-day mortality was the primary endpoint.
Results  Of the 102 enrolled patients, 51 received ACCM/PALS with ScvO2 goal-directed therapy and 51 received ACCM/PALS without ScvO2 goal-directed therapy. ScvO2 goal-directed therapy resulted in less mortality (28-day mortality 11.8% vs. 39.2%, p=0.002), and fewer new organ dysfunctions (p=0.03). ScvO2 goal-directed therapy resulted in more crystalloid (28 (20–40) vs. 5 (0–20)ml/kg, p<0.0001), blood transfusion (45.1% vs. 15.7%, p=0.002) and inotropic (29.4% vs. 7.8%, p=0.01) support in the first 6h.

Conclusions
This study supports the current ACCM/PALS guidelines. Goal-directed therapy using the endpoint of a ScvO2>=70% has a significant and additive impact on the outcome of children and adolescents with septic shock.

See the Editorial by M J Peters and J Brierley: Back to basics in septic shock

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