Intrathecal analgesia and restrictive perioperative fluid management within enhanced recovery pathway: hemodynamic implications.

BACKGROUND: Intrathecal analgesia and avoidance of perioperative fluid overload are key items within enhanced recovery pathways. Potential side effects include hypotension and renal dysfunction. STUDY DESIGN: From January 2010 until May 2010, all patients undergoing colorectal surgery within enhanced recovery pathways were included in this retrospective cohort study and were analyzed by intrathecal analgesia (IT) vs none (noIT). Primary outcomes measures were systolic and diastolic blood pressure, mean arterial pressure, and heart rate for 48 hours after surgery. Renal function was assessed by urine output and creatinine values. RESULTS: One hundred and sixty-three consecutive colorectal patients (127 IT and 36 noIT) were included in the analysis. Both patient groups showed low blood pressure values within the first 4 to 12 hours and a steady increase thereafter before return to baseline values after about 24 hours. Systolic and diastolic blood pressure and mean arterial pressure were significantly lower until 16 hours after surgery in patients having IT compared with the noIT group. Low urine output (<0.5 mL/kg/h) was reported in 11% vs 29% (IT vs noIT; p = 0.010) intraoperatively, 20% vs 11% (p = 0.387), 33% vs 22% (p = 0.304), and 31% vs 21% (p = 0.478) for postanesthesia care unit and postoperative days 1 and 2, respectively. Only 3 of 127 (2.4%) IT and 1 of 36 (2.8%) noIT patients had a transitory creatinine increase >50%; no patients required dialysis. CONCLUSIONS: Postoperative hypotension affects approximately 10% of patients within an enhanced recovery pathway and is slightly more pronounced in patients with IT. Hemodynamic depression persists for <20 hours after surgery; it has no measurable negative impact and therefore cannot justify detrimental postoperative fluid overload.

A prospective, randomized, and controlled study of fluid management in children with severe head injury: lactated Ringer's solution versus hypertonic saline.

OBJECTIVES: Resuscitation in severe head injury may be detrimental when given with hypotonic fluids. We evaluated the effects of lactated Ringer's solution (sodium 131 mmol/L, 277 mOsm/L) compared with hypertonic saline (sodium 268 mmol/L, 598 mOsm/L) in severely head-injured children over the first 3 days after injury. DESIGN: An open, randomized, and prospective study. SETTING: A 16-bed pediatric intensive care unit (ICU) (level III) at a university children's hospital. PATIENTS: A total of 35 consecutive children with head injury. INTERVENTIONS: Thirty-two children with Glasgow Coma Scores of <8 were randomly assigned to receive either lactated Ringer's solution (group 1) or hypertonic saline (group 2). Routine care was standardized, and included the following: head positioning at 30 degrees; normothermia (96.8 degrees to 98.6 degrees F [36 degrees to 37 degrees C]); analgesia and sedation with morphine (10 to 30 microg/kg/hr), midazolam (0.2 to 0.3 mg/kg/hr), and phenobarbital; volume-controlled ventilation (PaCO2 of 26.3 to 30 torr [3.5 to 4 kPa]); and optimal oxygenation (PaO2 of 90 to 105 torr [12 to 14 kPa], oxygen saturation of >92%, and hematocrit of >0.30). MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure and intracranial pressure (ICP) were monitored continuously and documented hourly and at every intervention. The means of every 4-hr period were calculated and serum sodium concentrations were measured at the same time. An ICP of 15 mm Hg was treated with a predefined sequence of interventions, and complications were documented. There was no difference with respect to age, male/female ratio, or initial Glasgow Coma Score. In both groups, there was an inverse correlation between serum sodium concentration and ICP (group 1: r = -.13, r2 = .02, p < .03; group 2: r = -.29, r2 = .08, p < .001) that disappeared in group 1 and increased in group 2 (group 1: r = -.08, r2 = .01, NS; group 2: r = -.35, r2 =.12, p < .001). Correlation between serum sodium concentration and cerebral perfusion pressure (CPP) became significant in group 2 after 8 hrs of treatment (r = .2, r2 = .04, p = .002). Over time, ICP and CPP did not significantly differ between the groups. However, to keep ICP at <15 mm Hg, group 2 patients required significantly fewer interventions (p < .02). Group 1 patients received less sodium (8.0 +/- 4.5 vs. 11.5 +/- 5.0 mmol/kg/day, p = .05) and more fluid on day 1 (2850 +/- 1480 vs. 2180 +/- 770 mL/m2, p = .05). They also had a higher frequency of acute respiratory distress syndrome (four vs. 0 patients, p = .1) and more than two complications (six vs. 1 patient, p = .09). Group 2 patients had significantly shorter ICU stay times (11.6 +/- 6.1 vs. 8.0 +/- 2.4 days; p = .04) and shorter mechanical ventilation times (9.5 +/- 6.0 vs. 6.9 +/- 2.2 days; p = .1). The survival rate and duration of hospital stay were similar in both groups. CONCLUSIONS: Treatment of severe head injury with hypertonic saline is superior to that treatment with lactated Ringer's solution. An increase in serum sodium concentrations significantly correlates with lower ICP and higher CPP. Children treated with hypertonic saline require fewer interventions, have fewer complications, and stay a shorter time in the ICU.

Goal-directed fluid management based on pulse pressure variation monitoring during high-risk surgery: a pilot randomized controlled trial

Abstract Introduction Several studies have shown that maximizing stroke volume (or increasing it until a plateau is reached) by volume loading during high-risk surgery may improve post-operative outcome. This goal could be achieved simply by minimizing the variation in arterial pulse pressure (ΔPP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomized, single-centre study. The primary endpoint was the length of postoperative stay in hospital. Methods Thirty-three patients undergoing high-risk surgery were randomized either to a control group (group C, n = 16) or to an intervention group (group I, n = 17). In group I, ΔPP was continuously monitored during surgery by a multiparameter bedside monitor and minimized to 10% or less by volume loading. Results Both groups were comparable in terms of demographic data, American Society of Anesthesiology score, type, and duration of surgery. During surgery, group I received more fluid than group C (4,618 ± 1,557 versus 1,694 ± 705 ml (mean ± SD), P < 0.0001), and ΔPP decreased from 22 ± 75 to 9 ± 1% (P < 0.05) in group I. The median duration of postoperative stay in hospital (7 versus 17 days, P < 0.01) was lower in group I than in group C. The number of postoperative complications per patient (1.4 ± 2.1 versus 3.9 ± 2.8, P < 0.05), as well as the median duration of mechanical ventilation (1 versus 5 days, P < 0.05) and stay in the intensive care unit (3 versus 9 days, P < 0.01) was also lower in group I. Conclusion Monitoring and minimizing ΔPP by volume loading during high-risk surgery improves postoperative outcome and decreases the length of stay in hospital. Trial registration NCT00479011

Perioperative fluid management: comparison of high, medium and low fluid volume on tissue oxygen pressure in the small bowel and colon

BACKGROUND AND OBJECTIVE: Insufficient blood flow and oxygenation in the intestinal tract is associated with increased incidence of postoperative complications after bowel surgery. High fluid volume administration may prevent occult regional hypoperfusion and intestinal tissue hypoxia. We tested the hypothesis that high intraoperative fluid volume administration increases intestinal wall tissue oxygen pressure during laparotomy. METHODS: In all, 27 pigs were anaesthetized, ventilated and randomly assigned to one of the three treatment groups (n = 9 in each) receiving low (3 mL kg-1 h-1), medium (7 mL kg-1 h-1) or high (20 mL kg-1 h-1) fluid volume treatment with lactated Ringer's solution. All animals received 30% and 100% inspired oxygen in random order. Cardiac index was measured with thermodilution and tissue oxygen pressure with a micro-oximetry system in the jejunum and colon wall and subcutaneous tissue. RESULTS: Groups receiving low and medium fluid volume treatment had similar systemic haemodynamics. The high fluid volume group had significantly higher mean arterial pressure, cardiac index and subcutaneous tissue oxygenation. Tissue oxygen pressures in the jejunum and colon were comparable in all three groups. CONCLUSIONS: The three different fluid volume regimens tested did not affect tissue oxygen pressure in the jejunum and colon, suggesting efficient autoregulation of intestinal blood flow in healthy subjects undergoing uncomplicated abdominal surgery.

Superior functional outcome after radical cystectomy and orthotopic bladder substitution with restrictive intraoperative fluid management: a followup study of a randomized clinical trial

PURPOSE Continuous intraoperative norepinephrine infusion combined with restrictive deferred hydration improves surgical field visibility, and significantly decreases intraoperative blood loss and postoperative complications in patients undergoing radical cystectomy and urinary diversion. We determined whether the intraoperative fluid regimen would affect functional results (continence and erectile function) 1 year after orthotopic ileal bladder substitution. MATERIALS AND METHODS We analyzed a subgroup of 93 patients who received an ileal orthotopic bladder substitute. The subgroup was part of a randomized trial in 167 patients initially allocated to continuous norepinephrine administration starting with 2 μg/kg per hour combined with 1 ml/kg per hour initially and 3 ml/kg per hour crystalloid infusion after cystectomy (norepinephrine/low volume group of 51) or a standard crystalloid infusion of 6 ml/kg per hour throughout surgery (42 controls). We prospectively assessed daytime and nighttime continence, and erectile function 1 year postoperatively in the 93-patient subgroup. RESULTS Daytime continence was reported by 44 of 51 patients (86%) in the norepinephrine/low volume group and by 27 of 42 controls (64%) (p = 0.016), and nighttime continence was reported by 38 (75%) and 25 (60%), respectively (p = 0.077). Erectile function recovery was reported by 26 of 33 preoperatively potent patients (79%) in the norepinephrine/low volume group and by 11 of 29 controls (38%) (p = 0.002). CONCLUSIONS Patients who undergo radical cystectomy and orthotopic bladder substitution with continuous norepinephrine infusion and restrictive hydration during surgery have significantly better daytime continence and erectile function 1 year postoperatively.

Fluid management and goal-directed therapy as an adjunct to Enhanced Recovery After Surgery (ERAS)

© 2014, Canadian Anesthesiologists' Society.Optimal perioperative fluid management is an important component of Enhanced Recovery After Surgery (ERAS) pathways. Fluid management within ERAS should be viewed as a continuum through the preoperative, intraoperative, and postoperative phases. Each phase is important for improving patient outcomes, and suboptimal care in one phase can undermine best practice within the rest of the ERAS pathway. The goal of preoperative fluid management is for the patient to arrive in the operating room in a hydrated and euvolemic state. To achieve this, prolonged fasting is not recommended, and routine mechanical bowel preparation should be avoided. Patients should be encouraged to ingest a clear carbohydrate drink two to three hours before surgery. The goals of intraoperative fluid management are to maintain central euvolemia and to avoid excess salt and water. To achieve this, patients undergoing surgery within an enhanced recovery protocol should have an individualized fluid management plan. As part of this plan, excess crystalloid should be avoided in all patients. For low-risk patients undergoing low-risk surgery, a “zero-balance” approach might be sufficient. In addition, for most patients undergoing major surgery, individualized goal-directed fluid therapy (GDFT) is recommended. Ultimately, however, the additional benefit of GDFT should be determined based on surgical and patient risk factors. Postoperatively, once fluid intake is established, intravenous fluid administration can be discontinued and restarted only if clinically indicated. In the absence of other concerns, detrimental postoperative fluid overload is not justified and “permissive oliguria” could be tolerated.

Conservative fluid management or deresuscitation for patients with sepsis or acute respiratory distress syndrome following the resuscitation phase of critical illness: a systematic review and meta-analysis

Background

It is unknown whether a conservative approach to fluid administration or deresuscitation (active removal of fluid using diuretics or renal replacement therapy) is beneficial following haemodynamic stabilisation of critically ill patients.

Purpose

To evaluate the efficacy and safety of conservative or deresuscitative fluid strategies in adults and children with acute respiratory distress syndrome (ARDS), sepsis or systemic inflammatory response syndrome (SIRS) in the post-resuscitation phase of critical illness.

Methods

We searched Medline, EMBASE and the Cochrane central register of controlled trials from 1980 to June 2016, and manually reviewed relevant conference proceedings from 2009 to the present. Two reviewers independently assessed search results for inclusion and undertook data extraction and quality appraisal. We included randomised trials comparing fluid regimens with differing fluid balances between groups, and observational studies investigating the relationship between fluid balance and clinical outcomes.

Results

Forty-nine studies met the inclusion criteria. Marked clinical heterogeneity was evident. In a meta-analysis of 11 randomised trials (2051 patients) using a random-effects model, we found no significant difference in mortality with conservative or deresuscitative strategies compared with a liberal strategy or usual care [pooled risk ratio (RR) 0.92, 95 % confidence interval (CI) 0.82–1.02, I2 = 0 %]. A conservative or deresuscitative strategy resulted in increased ventilator-free days (mean difference 1.82 days, 95 % CI 0.53–3.10, I2 = 9 %) and reduced length of ICU stay (mean difference −1.88 days, 95 % CI −0.12 to −3.64, I2 = 75 %) compared with a liberal strategy or standard care.

Conclusions

In adults and children with ARDS, sepsis or SIRS, a conservative or deresuscitative fluid strategy results in an increased number of ventilator-free days and a decreased length of ICU stay compared with a liberal strategy or standard care. The effect on mortality remains uncertain. Large randomised trials are needed to determine optimal fluid strategies in critical illness.

New perioperative fluid and pharmacologic management protocol results in reduced blood loss, faster return of bowel function, and overall recovery.

Cystectomy and urinary diversion have high morbidity, and strategies to reduce complications are of utmost importance. Epidural analgesia and optimized fluid management are considered key factors contributing to successful enhanced recovery after surgery. In colorectal surgery, there is strong evidence that an intraoperative fluid management aiming for a postoperative zero fluid balance results in lower morbidity including a faster return of bowel function. Recently, a randomized clinical trial focusing on radical cystectomy demonstrated that a restrictive intraoperative hydration combined with a concomitant administration of norepinephrine reduced intraoperative blood loss, the need for blood transfusion and morbidity. The purpose of this review is to highlight specific anesthesiological aspects which have been shown to improve outcome after RC with urinary diversion.

Pulse pressure variation-guided fluid therapy after cardiac surgery: A pilot before-and-after trial.

PURPOSE: The aim of this study is to study the feasibility, safety, and physiological effects of pulse pressure variation (PPV)-guided fluid therapy in patients after cardiac surgery. MATERIALS AND METHODS: We conducted a pilot prospective before-and-after study during mandatory ventilation after cardiac surgery in a tertiary intensive care unit. We introduced a protocol to deliver a fluid bolus for a PPV ≥13% for at least >10 minutes during the intervention period. RESULTS: We studied 45 control patients and 53 intervention patients. During the intervention period, clinicians administered a fluid bolus on 79% of the defined PPV trigger episodes. Median total fluid intake was similar between 2 groups during mandatory ventilation (1297 mL [interquartile range 549-1968] vs 1481 mL [807-2563]; P = .17) and the first 24 hours (3046 mL [interquartile range 2317-3982] vs 3017 mL [2192-4028]; P = .73). After adjusting for several baseline factors, PPV-guided fluid management significantly increased fluid intake during mandatory ventilation (P = .004) but not during the first 24 hours (P = .47). Pulse pressure variation-guided fluid therapy, however, did not significantly affect hemodynamic, renal, and metabolic variables. No serious adverse events were noted. CONCLUSIONS: Pulse pressure variation-guided fluid management was feasible and safe during mandatory ventilation after cardiac surgery. However, its advantages may be clinically small.

Postoperative splanchnic blood flow redistribution in response to fluid challenges in the presence and absence of endotoxemia in a porcine model

We hypothesized that fluid administration may increase regional splanchnic perfusion after abdominal surgery-even in the absence of a cardiac stroke volume (SV) increase and independent of accompanying endotoxemia. Sixteen anesthetized pigs underwent abdominal surgery with flow probe fitting around splanchnic vessels and carotid arteries. They were randomized to continuous placebo or endotoxin infusion, and when clinical signs of hypovolemia (mean arterial pressure, <60 mmHg; heart rate, >100 beats · min(-1); urine production, <0.5 mL · kg(-1) · h(-1); arterial lactate concentration, >2 mmol · L(-1)) and/or low pulmonary artery occlusion pressure (target 5-8 mmHg) were present, they received repeated boli of colloids (50 mL) as long as SV increased 10% or greater. Stroke volume and regional blood flows were monitored 2 min before and 30 min after fluid challenges. Of 132 fluid challenges, 45 (34%) resulted in an SV increase of 10% or greater, whereas 82 (62%) resulted in an increase of 10% or greater in one or more of the abdominal flows (P < 0.001). During blood flow redistribution, celiac trunk (19% of all measurements) and hepatic artery flow (15%) most often decreased, whereas portal vein (10%) and carotid artery (7%) flow decreased less frequently (P = 0.015, between regions). In control animals, celiac trunk (30% vs. 9%, P = 0.004) and hepatic artery (25% vs. 11%, P = 0.040) flow decreased more often than in endotoxin-infused pigs. Accordingly, blood flow redistribution is a common phenomenon in the postoperative period and is only marginally influenced by endotoxemia. Fluid management based on SV changes may not be useful for improving regional abdominal perfusion.

[Arterial pressure curve and fluid status.]

Fluid optimization is a major contributor to improved outcome in patients. Unfortunately, anesthesiologists are often in doubt whether an additional fluid bolus will improve the hemodynamics of the patient or not as excess fluid may even jeopardize the condition. This article discusses physiological concepts of liberal versus restrictive fluid management followed by a discussion on the respective capabilities of various monitors to predict fluid responsiveness. The parameter difference in pulse pressure (dPP), derived from heart-lung interaction in mechanically ventilated patients is discussed in detail. The dPP cutoff value of 13% to predict fluid responsiveness is presented together with several assessment techniques of dPP. Finally, confounding variables on dPP measurements, such as ventilation parameters, pneumoperitoneum and use of norepinephrine are also mentioned.

Effect of fluid resuscitation on mortality and organ function in experimental sepsis models

Introduction Several recent studies have shown that a positive fluid balance in critical illness is associated with worse outcome. We tested the effects of moderate vs. high-volume resuscitation strategies on mortality, systemic and regional blood flows, mitochondrial respiration, and organ function in two experimental sepsis models. Methods 48 pigs were randomized to continuous endotoxin infusion, fecal peritonitis, and a control group (n = 16 each), and each group further to two different basal rates of volume supply for 24 hours [moderate-volume (10 ml/kg/h, Ringer's lactate, n = 8); high-volume (15 + 5 ml/kg/h, Ringer's lactate and hydroxyethyl starch (HES), n = 8)], both supplemented by additional volume boli, as guided by urinary output, filling pressures, and responses in stroke volume. Systemic and regional hemodynamics were measured and tissue specimens taken for mitochondrial function assessment and histological analysis. Results Mortality in high-volume groups was 87% (peritonitis), 75% (endotoxemia), and 13% (controls). In moderate-volume groups mortality was 50% (peritonitis), 13% (endotoxemia) and 0% (controls). Both septic groups became hyperdynamic. While neither sepsis nor volume resuscitation strategy was associated with altered hepatic or muscle mitochondrial complex I- and II-dependent respiration, non-survivors had lower hepatic complex II-dependent respiratory control ratios (2.6 +/- 0.7, vs. 3.3 +/- 0.9 in survivors; P = 0.01). Histology revealed moderate damage in all organs, colloid plaques in lung tissue of high-volume groups, and severe kidney damage in endotoxin high-volume animals. Conclusions High-volume resuscitation including HES in experimental peritonitis and endotoxemia increased mortality despite better initial hemodynamic stability. This suggests that the strategy of early fluid management influences outcome in sepsis. The high mortality was not associated with reduced mitochondrial complex I- or II-dependent muscle and hepatic respiration.

Low Hematocrit Levels Increase Intracranial Pressure in an Animal Model of Cryogenic Brain Injury

Background: Brain injury is responsible for significant morbidity and mortality in trauma patients, but controversy still exists over optimal fluid management for these patients. This study aimed to investigate the effects of acute hemodilution with hydroxyethyl starch (HES) or lactated Ringer`s solution (LR) in intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in dogs submitted to a cryogenic brain injury model. Methods: Design-Prospective laboratory animal study. Setting-Research laboratory in a teaching hospital. Subjects-Thirty-five male mongrel dogs. Interventions-Animals were enrolled to five groups: control, hemodilution with LR or HES 6% to an hematocrit target of 27% or 35%. Results: ICP and CPP levels were measured after cryogenic brain injury. Hemodilution promotes an increment of ICP levels, which decreases CPP when hematocrit target was estimated in 27.% after hemodilution. However, no differences were observed regarding crystalloid or colloid solution used for hemodilution in ICP and CPP levels. Conclusions: Hemodilution to a low hematocrit level increases ICP and decreases CPP scores in dogs submitted to a cryogenic brain injury. These results suggest that excessive hemodilution to a hematocrit below 30% should be avoided in traumatic brain injury patients.

Hypervolemia induces and potentiates lung damage after recruitment maneuver in a model of sepsis-induced acute lung injury

Introduction: Recruitment maneuvers (RMs) seem to be more effective in extrapulmonary acute lung injury (ALI), caused mainly by sepsis, than in pulmonary ALI. Nevertheless, the maintenance of adequate volemic status is particularly challenging in sepsis. Since the interaction between volemic status and RMs is not well established, we investigated the effects of RMs on lung and distal organs in the presence of hypovolemia, normovolemia, and hypervolemia in a model of extrapulmonary lung injury induced by sepsis. Methods: ALI was induced by cecal ligation and puncture surgery in 66 Wistar rats. After 48 h, animals were anesthetized, mechanically ventilated and randomly assigned to 3 volemic status (n = 22/group): 1) hypovolemia induced by blood drainage at mean arterial pressure (MAP)approximate to 70 mmHg; 2) normovolemia (MAP approximate to 100 mmHg), and 3) hypervolemia with colloid administration to achieve a MAP approximate to 130 mmHg. In each group, animals were further randomized to be recruited (CPAP = 40 cm H(2)O for 40 s) or not (NR) (n = 11/group), followed by 1 h of protective mechanical ventilation. Echocardiography, arterial blood gases, static lung elastance (Est, L), histology (light and electron microscopy), lung wet-to-dry (W/D) ratio, interleukin (IL)-6, IL-1 beta, caspase-3, type III procollagen (PCIII), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) mRNA expressions in lung tissue, as well as lung and distal organ epithelial cell apoptosis were analyzed. Results: We observed that: 1) hypervolemia increased lung W/D ratio with impairment of oxygenation and Est, L, and was associated with alveolar and endothelial cell damage and increased IL-6, VCAM-1, and ICAM-1 mRNA expressions; and 2) RM reduced alveolar collapse independent of volemic status. In hypervolemic animals, RM improved oxygenation above the levels observed with the use of positive-end expiratory pressure (PEEP), but increased lung injury and led to higher inflammatory and fibrogenetic responses. Conclusions: Volemic status should be taken into account during RMs, since in this sepsis-induced ALI model hypervolemia promoted and potentiated lung injury compared to hypo-and normovolemia.

Avaliação ecocardiográfica da influência do jejum na resposta a um aumento reversível da pré-carga

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular - Ramo de especialização: Ultrassonografia Cardiovascular