Colloid vs. crystalloid infusions in gastrointestinal surgery and their different impact on the healing of intestinal anastomoses

Goal-directed therapy with bolus albumin 5% is not superior to bolus ringer acetate in maintaining systemic and mesenteric oxygen delivery in major upper abdominal surgery: A randomised controlled trial

BACKGROUND

Goal-directed therapy (GDT) is increasingly used in abdominal surgery. Whether crystalloids can exert the same effect as colloid, and how this may affect perfusion, is still unclear. The effect of GDT on the systemic oxygen delivery index (sDO2I) and the mesenteric oxygen delivery index (mDO2I) can be quantified by measuring cardiac index and flow in the superior mesenteric artery, respectively.

OBJECTIVE

The aim of this study was to test the hypothesis that intra-operative GDT with bolus human albumin 5% is superior to GDT with bolus ringer acetate in maintaining sDO2I and mDO2I in elective major upper gastrointestinal cancer surgery.

DESIGN

Randomised controlled double blinded trial.

SETTING

Odense University Hospital, Denmark, from May 2014 to June 2015.

PATIENTS

A total of 89 adults scheduled for elective major upper gastrointestinal cancer surgery were randomised and data from 60 were analysed.

EXCLUSION CRITERIA

contraindications for using the LiDCOplus system, known allergy to albumin, pre-operative renal failure, pancreatic cancer and pre-operative down staging using chemotherapy and/or radiation therapy, pregnancy.

INTERVENTIONS

Patients were randomised to intra-operative GDT with either bolus human albumin or ringer acetate 250 ml, guided by pulse pressure variation and stroke volume.

MAIN OUTCOME MEASURES

Changes in sDO2I and mDO2I. Secondary outcomes were changes in other haemodynamic variables, fluid balance, blood transfusions, fluid-related complications and length of stay (LOS) in ICU and hospital.

RESULTS

Median [IQR] sDO2I was 522 [420 to 665] ml min m in the ringer acetate group and 490 [363 to 676] ml min m in the human albumin group, P = 0.36. Median [IQR] mDO2I was 12.1 [5.8 to 28.7] ml min m in the ringer acetate group and 17.0 [7.6 to 27.5] ml min m in the human albumin group, P = 0.17. Other haemodynamic comparisons did not differ significantly. More trial fluid was administered in the ringer acetate group. We found no significant difference in transfusions, complications or LOS.

CONCLUSION

Bolus human albumin 5% was not superior to bolus ringer acetate in maintaining systemic or mesenteric oxygen delivery in elective major upper gastrointestinal cancer surgery, despite the administration of larger volumes of trial fluid in the ringer acetate group. No significant difference was seen in fluid-related complications or LOS.

TRIAL REGISTRATION

https://eudract.ema.europa.eu/ Identifier: 2013-002217-36.

Intraoperative Intravascular Effect of Lactated Ringer's Solution and Hyperoncotic Albumin During Hemorrhage in Cystectomy Patients

BACKGROUND

The intraoperative effect of 20% albumin on plasma volume during surgery involving major blood loss has not been explored extensively due to methodological difficulties. Crystalloids poorly expand the plasma volume, and using a colloid might then be a way to avoid fluid overload. As doubts have been raised about synthetic colloids, albumin solutions are currently used more extensively. This study presents a methodological development showing how plasma volume expansion can be studied in surgical settings with the coinfusion of 20% albumin and lactated Ringer's solution.

METHODS

In this single-arm, single-center feasibility study, an intravenous (i.v.) infusion of 3 mL·kg·BW-1 of 20% albumin was administered over 30 minutes to 23 cystectomy patients during the bleeding phase in addition to lactated Ringer's solution to correct blood loss. Blood samples were measured at regular intervals over a period of 300 minutes to estimate the blood volume expansion resulting from simultaneous infusions of lactated Ringer's and 20% albumin solutions, using a regression equation and the area under the volume-time curve method.

RESULTS

Mean hemorrhage was 974 mL (standard deviation [SD] ± 381). The regression method showed strong correlation (r2 = 0.58) between blood loss minus blood volume expansion and the independent effects of the infused volume of lactated Ringer's and 20% albumin solutions. The mean plasma volume expansion attributable to the infusion of lactated Ringer's solution amounted to 0.38 (95% confidence interval [CI], 0.31-0.49) of the infused volume; for the 20% albumin, it was 1.94 mL/mL (95% CI, 1.41-2.46 mL/mL) over 5 hours on average (regression method). The mean within-patient change was 0.20 mL/mL (± 0.06 mL/mL) for the lactated Ringer's solution and 2.20 mL/mL (±1.31 mL/mL) for the 20% albumin using the area under the volume-time curve method.

CONCLUSIONS

Blood volume expansion averaged 1.9-2.2 times the infused volume of 20% albumin during surgery associated with hemorrhage of around 1000 mL. This effect was long standing and approximately 5 times stronger than for the lactated Ringer's solution. Twenty percent albumin boosts the plasma volume expansion of lactated Ringer's solution to as high as 40% of the infused volume on the average, which is an effect that lasts at least 5 hours.

Initial Evaluation and Care of the Patient with New-Onset Intestinal Failure

A total parenteral nutrition (TPN) formula needs to be correctly compounded with the help of a pharmacist and patients cycled to ensure they are tolerating the TPN volume. Selection of and close working relationship with a home infusion company needs to be arranged prior to hospital discharge and can be coordinated with the help of a hospital case manager. For Medicare patients, a certificate of medical necessity must be completed and signed prior to hospital discharge. Patients should undergo education regarding catheter care, infusion pump programming, and preparation of the TPN solution with additives, such as multivitamins and trace elements.

Effect of restrictive fluid therapy with hydroxyethyl starch during esophagectomy on postoperative outcomes: a retrospective cohort study

BACKGROUND

To improve prognosis after esophageal surgery, intraoperative fluid optimization is important. Herein, we hypothesized that hydroxyethyl starch administration during esophagectomy reduce the total amount of fluid infused and it could have a positive effect on postoperative complication occurrence and mortality.

METHODS

All consecutive adult patients who underwent elective esophageal surgery for cancer were studied. The primary outcome was the development of composite complications including death, cardio-cerebrovascular complications, respiratory complications, renal complications, gastrointestinal complications, sepsis, empyema or abscess, and multi-organ failure. The relationship between perioperative variables and composite complication was evaluated using multivariable logistic regression.

RESULTS

Of 892 patients analyzed, composite complications developed in 271 (30.4%). The higher hydroxyethyl starch ratio in total fluid had a negative relationship with the total fluid infusion amount (r = - 0.256, P <  0.001). In multivariable analysis, intraoperatively administered total fluid per weight per hour (odds ratio, 1.248; 95% CI, 1.153-1.351; P <  0.001) and HES-to-crystalloid ratio (odds ratio, 2.125; 95% CI, 1.521-2.969; P <  0.001) were associated with increased risks of postoperative composite outcomes.

CONCLUSIONS

Although hydroxyethyl starch administration reduces the total fluid infusion amount during esophageal surgery for cancer, intravenous hydroxyethyl starch infusion is associated with an increasing risk of postoperative composite complications.

Postoperative fluid overload is a risk factor for adverse surgical outcome in patients undergoing esophagectomy for esophageal cancer: a retrospective study in 335 patients

Background

Restrictive intraoperative fluid management is increasingly recommended for patients undergoing esophagectomy. Controversy still exists about the impact of postoperative fluid management on perioperative outcome.

Methods

We retrospectively examined 335 patients who had undergone esophagectomy for esophageal cancer at the University Hospital Freiburg between 1996 and 2014 to investigate the relation between intra- and postoperative fluid management and postoperative morbidity after esophagectomy.

Results

Perioperative morbidity was 75%, the in-hospital mortality 8%. A fluid balance above average on the operation day was strongly associated with a higher rate of postoperative mortality (21% vs 3%, p < 0.001) and morbidity (83% vs 66%, p = 0.001). Univariate analysis for risk factors for adverse surgical outcome (Clavien ≥ III) identified ASA-score (p = 0.002), smoking (p = 0.036), reconstruction by colonic interposition (p = 0.036), cervical anastomosis (p = 0.017), blood transfusion (p = 0.038) and total fluid balance on the operation day and on POD 4 (p = 0.001) as risk factors.

Multivariate analysis confirmed only ASA-score (p = 0.001) and total fluid balance (p = 0.001) as independent predictors of adverse surgical outcome.

Conclusion

Intra- and postoperative fluid overload is strongly associated with increased postoperative morbidity. Our results suggest restrictive intra- and especially postoperative fluid management to optimize the outcome after esophagectomy.

Impact of a Potassium-enriched, Chloride-depleted 5% Glucose Solution on Gastrointestinal Function after Major Abdominopelvic Surgery

Background

Gastrointestinal (GI) complications often delay recovery after radical cystectomy with urinary diversion. The authors investigated if perioperative administration of a potassium-enriched, chloride-depleted 5% glucose solution (G5K) accelerates recovery of GI function.

Methods

This randomized, parallel-group, single-center double-blind trial included 44 consecutive patients undergoing radical cystectomy and pelvic lymph node dissection with urinary diversion. Patients were randomized to receive either a G5K (G5K group) solution or a Ringer’s maleate solution (control group). Fluid management aimed for a zero fluid balance. Primary endpoint was time to first defecation. Secondary endpoints were time to normal GI function, need for electrolyte substitution, and renal dysfunction.

Results

Time to first defecation was not significantly different between groups (G5K group, 93 h [19 to 168 h] and control group, 120 h [43 to 241 h]); estimator of the group difference, −16 (95% CI, −38 to 6); P = 0.173. Return of normal GI function occurred faster in the G5K group than in the control group (median, 138 h [range, 54 to 262 h] vs. 169 h [108 to 318 h]); estimator of the group difference, −38 (95% CI, −74 to −12); P = 0.004. Potassium and magnesium were less frequently substituted in the G5K group (13.6 vs. 54.5% [P = 0.010] and 18.2 vs. 77.3% [P &lt; 0.001]), respectively. The incidence of renal dysfunction (Risk, Injury, Failure, Loss and End-stage kidney disease stage “risk”) at discharge was 9.1% in the G5K group and 4.5% in the control group; P = 1.000.

Conclusions

Perioperative administration of a G5K did not enhance first defecation, but may accelerate recovery of normal GI function, and reduces potassium and magnesium substitution after radical cystectomy and urinary diversion.

Perioperative trends in plasma colloid osmotic pressure in horses undergoing surgery

OBJECTIVE

To compare perioperative trends in plasma colloid osmotic pressure (COP) between horses undergoing orthopedic and colic surgery.

DESIGN

Prospective clinical study September 2009-January 2011.

SETTING

Veterinary university teaching hospital.

ANIMALS

Thirty-three healthy, client-owned horses presenting for orthopedic surgery (non-GI) and 85 client-owned horses presenting for emergency exploratory celiotomy (GI, gastrointestinal).

INTERVENTIONS

None.

MEASUREMENTS

Data relating to the horse's parameters on presentation, surgical lesion, post-operative management and survival were extracted from computerized clinical records. Heparinized blood samples were taken on presentation (PreOp, pre-operative), on recovery from anesthesia (T0), at 12 (T12) and 24 (T24) hours post recovery. COP was measured within 4 hours of collection.

RESULTS

There was no significant difference in PreOp or T0 COP between groups. Both groups had a significant decrease in COP during anesthesia. When compared to their respective pre-operative values, horses in the non-GI group had significantly increased COP at T12, whereas those in the GI group had significantly reduced COP. This trend was continued at T24. Horses in the GI group placed on intravenous crystalloid isotonic fluids post-operatively had a significantly lower COP at T12 and T24. Horses in the GI group that did not survive had significantly lower post-operative COP values at T24.

CONCLUSIONS

Horses undergoing exploratory celiotomy had significantly lower COP post-operatively than those horses undergoing orthopedic surgery. This difference was more marked in those horses receiving isotonic crystalloid intravenous fluid therapy post-operatively and in those that did not survive to discharge. In the non-GI group an increase in COP post-operatively was common.

Crystalloid administration among patients undergoing liver surgery: Defining patient- and provider-level variation

BACKGROUND

Fluid administration among patients undergoing liver resection is a key aspect of perioperative care. We sought to examine practice patterns of crystalloid administration, as well as potential factors associated with receipt of crystalloid fluids.

METHOD

Patients who underwent liver resection between 2010 and 2014 were identified. Data on clinicopathologic variables, operative details, and perioperative fluid administration were collected and analyzed using univariable and multivariable analyses; variation in practice of crystalloid administration was presented as coefficient of variation (COV).

RESULTS

Among 487 patients, median crystalloid administered at the time of surgery was 4,000 mL. After adjusting for body size and operative duration, median corrected crystalloid was 30.0 mL kg(-1) m(2) h(-1), corresponding with a COV of 35%. Patients who received <30 mL kg(-1) m(2) h(-1) crystalloids were more likely to be younger (58 vs 60 years), white (79% vs 74%), and have a higher body mass index (BMI; 28.2 vs 25.4 kg/m(2); all P < .001). On multivariable analysis, increasing Charlson comorbidity index, BMI, estimated blood loss, and each additional hour of surgery were all associated with increased crystalloid administration (all P < .05). Corrected crystalloid administration varied among providers with a corrected COV ranging from 14% to 61%. When overall variation in crystalloid administration was assessed, 80% of the variation occurred at the patient level, and 20% occurred at the provider level (surgeon, 3% vs anesthesiologist, 17%).

CONCLUSION

There was wide variability in crystalloid administration among patients undergoing liver resection. Although the majority of variation was attributable to patient factors, a large amount of residual variation was attributable to provider-level differences.

Postoperative fluid management

Postoperative care units are run by an anesthesiologist or a surgeon, or a team formed of both. Management of postoperative fluid therapy should be done considering both patients’ status and intraoperative events. Types of the fluids, amount of the fluid given and timing of the administration are the main topics that determine the fluid management strategy. The main goal of fluid resuscitation is to provide adequate tissue perfusion without harming the patient. The endothelial glycocalyx dysfunction and fluid shift to extracellular compartment should be considered wisely. Fluid management must be done based on patient’s body fluid status. Patients who are responsive to fluids can benefit from fluid resuscitation, whereas patients who are not fluid responsive are more likely to suffer complications of over-hydration. Therefore, common use of central venous pressure measurement, which is proved to be inefficient to predict fluid responsiveness, should be avoided. Goal directed strategy is the most rational approach to assess the patient and maintain optimum fluid balance. However, accessible and applicable monitoring tools for determining patient’s actual fluid need should be further studied and universalized. The debate around colloids and crystalloids should also be considered with goal directed therapies. Advantages and disadvantages of each solution must be evaluated with the patient’s specific condition.

Impact of intraoperative fluid administration on outcome in patients undergoing robotic-assisted laparoscopic prostatectomy--a retrospective analysis

Background

Robotic-assisted laparoscopic prostatectomy (RALP) gained much popularity during the last decade. Although the influence of intraoperative fluid management on patients’ outcome has been largely discussed in general, its impact on perioperative complications and length of hospitalization in patients undergoing RALP has not been examined so far. We hypothesized that a more restrictive fluid management might lead to a shortened length of hospitalization and a decreased rate of complications in our patients.

Methods

Retrospective analysis of data of 182 patients undergoing RALP at an University Hospital (first series of RALP performed at the center).

Results

The amount of fluid administered was initially normalized for body mass index of the patient and the duration of the operation and additionally corrected for age and the interaction of these variables. The application of crystalloids (multiple linear regression model, estimate = -0.044, p = 0.734) had no effect on the length of hospitalization, whereas a negative effect was found for colloids (estimate = -8.317, p = 0.021). Additionally, a significant interaction term between age and the amount of colloid applied (estimate = 0.129, p = 0.028) was calculated. Evaluation of the influence of intraoperative fluid administration using multiple logistic regression models corrected for body mass index, duration of the surgery and additionally for age revealed a negative effect of crystalloids on the incidence of an anastomotic leak between bladder and urethra (estimate = -23.860, p = 0.017), with a significant interaction term between age and the amount of crystalloids (estimate = 0.396, p = 0.0134). Colloids had no significant effect on this particular complication (estimate = 1.887, p = 0.524). Intraoperative blood loss did not alter the incidence of an anastomotic leak (estimate = 0.001, p = 0.086), nor did it affect the length of hospitalization (estimate = 0.0001, p = 0.351).

Conclusions

In accordance to the findings of our study, we suggest that a standardized, more restrictive fluid management might be beneficial in patients undergoing RALP. In older patients this measure would be able to shorten the length of hospitalization and to decrease the incidence of anastomosis leakage as a major complication.

A randomised prospective trial of intra-operative oesophageal Doppler-guided fluid administration in major gynaecological surgery

Intra-operative oesophageal Doppler monitor-guided fluid management has been associated with improved postoperative length of hospital stay and morbidity in gastrointestinal and orthopaedic surgery. We designed a randomised controlled trial to test the hypothesis that this approach to intra-operative fluid management in major elective open gynaecological surgery would shorten the length of postoperative stay, defined as time to readiness for hospital discharge. Postoperative morbidity was evaluated as a secondary outcome. The oesophageal Doppler monitor group underwent intra-operative fluid management using an oesophageal Doppler-guided stroke volume optimisation algorithm. Control group (conventional fluid therapy) intra-operative fluid management was based on conventional haemodynamic indices. In a single centre, 102 patients were randomly assigned: 51 to the oesophageal Doppler monitor group (51 analysed) and 51 to the control group (50 analysed). Evaluators who were blinded to patient assignment collected postoperative outcome data. There was no difference in the length of postoperative hospital stay between the groups: median (IQR [range]) number of days until ready for discharge was 6 (5-8 [4-25]) days in the oesophageal Doppler monitor group compared with 7 (5-9 [4-42]) days in the control group, p = 0.5. There was no difference between the groups in postoperative morbidity survey scores on postoperative days 1, 3 or 5. Seven patients in the oesophageal Doppler monitor group and 11 in the control group experienced postoperative complications (p = 0.41). These findings question whether intra-operative oesophageal Doppler-guided fluid therapy is of benefit in patients undergoing open gynaecological surgery.

Intraoperative crystalloid overload leads to substantial inflammatory infiltration of intestinal anastomoses-a histomorphological analysis

BACKGROUND

It has been shown that crystalloid fluid-overload promotes anastomotic instability. As physiologic anastomotic healing requires the sequential infiltration of different cells, we hypothesized this to be altered by liberal fluid regimes and performed a histomorphological analysis.

METHODS

36 Wistar rats were randomized into 4 groups (n=8-10 rats/group) and treated with either liberal (+) or restrictive (-) perioperative crystalline (Jonosteril = Cry) or colloidal fluid (Voluven = Col). Anastomotic samples were obtained on postoperative day 4, routinely stained and histophathologically reviewed. Anastomotic healing was assessed using a semiquantitative score, assessing inflammatory cells, anastomotic repair and collagenase activity.

RESULTS

Overall, the crystalloid overload group (Cry (+)) showed the worst healing score (P < 0.01). A substantial increase of lymphocytes and macrophages was found in this group compared to the other three (P < 0.01). Both groups that received colloidal fluid (Col (+) and Col (-)) as well as the group that received restricted crystalloid fluid resuscitation (Cry (-)) had better intestinal healing. Collagenase activity was significantly higher in the Cry (+) group.

CONCLUSION

Intraoperative infusion of high-volume crystalloid fluid leads to a pathological anastomotic inflammatory response with a marked infiltration of leukocytes and macrophages resulting in accelerated collagenolysis.

The effect of fluid overload in the presence of an epidural on the strength of colonic anastomoses

BACKGROUND

Despite the beneficial effects of epidurals in intra-abdominal surgery, the incidence of anastomotic leak remains controversial when used. Moreover, studies have also shown that fluid overload may be deleterious to anastomoses. The purpose of this paper is to evaluate the effects of varying intraoperative fluid protocols, in the presence of an epidural, on the burst pressure strength of colonic anastomoses.

METHODS

An epidural was installed in 18 rabbits, divided into three groups. Group 1 received 30 mL/kg/h Ringer's lactate, Group 2 received 100 mL/kg/h Ringer's lactate, and Group 3 received 30 mL/kg/h Pentaspan. Two colo-colonic anastomoses were performed per rabbit. On postoperative day 7 the anastomoses were resected and their burst pressures measured as a surrogate for anastomotic leak.

RESULTS

When comparing the average burst pressures of all three groups, there was a significant difference (P = 0.04). The anastomoses in the 100 mL/kg/h Ringer's lactate group were shown to be the weakest, with 64% of the anastomoses having burst under 120 mm Hg. The rabbits hydrated with Pentaspan had the highest strength, with no anastomoses bursting under 120 mm Hg. This translated into significant burst pressure differences (P = 0.02) between Group 2 and Group 3.

CONCLUSION

These results suggest that fluid overload with a crystalloid, in the presence of an epidural, may be deleterious to the healing of colonic anastomoses, creating a higher risk of anastomotic leak. Intraoperative resuscitation should thus focus on goal-directed euvolemia with appropriate amounts of colloids and/or crystalloids to prevent the risk of weakening anastomoses, especially in patients with epidurals.

Anesthetic management for esophageal resection

Surgical resection remains a standard treatment option for localized esophageal cancer. Surgical approaches to esophagectomy include transhiatal and transthoracic techniques as well as minimally invasive techniques that have been developed to reduce the morbidities associated with laparotomy and thoracotomy incisions. The perioperative mortality for esophagectomy remains high with cardiopulmonary and anastomotic complications as the most frequent and serious morbidities. This article reviews the management of patients presenting for esophagectomy, with a focus on evidence-based anesthetic and perioperative approaches for improving outcomes.

Intraoperative fluid management in open gastrointestinal surgery: goal-directed versus restrictive

OBJECTIVE

The optimal strategy for fluid management during gastrointestinal surgery remains unclear. Minimizing the variation in arterial pulse pressure, which is induced by mechanical ventilation, is a potential strategy to improve postoperative outcomes. We tested this hypothesis in a prospective, randomized study with lactated Ringer's solution and 6% hydroxyethyl starch solution.

METHOD

A total of 60 patients who were undergoing gastrointestinal surgery were randomized into a restrictive lactated Ringer's group (n = 20), a goal-directed lactated Ringer's group (n = 20) and a goal-directed hydroxyethyl starch group (n = 20). The goal-directed fluid treatment was guided by pulse pressure variation, which was recorded during surgery using a simple manual method with a Datex Ohmeda S/5 Monitor and minimized to 11% or less by volume loading with either lactated Ringer's solution or 6% hydroxyethyl starch solution (130/0.4). The postoperative flatus time, the length of hospital stay and the incidence of complications were recorded as endpoints.

RESULTS

The goal-directed lactated Ringer's group received the greatest amount of total operative fluid compared with the two other groups. The flatus time and the length of hospital stay in the goal-directed hydroxyethyl starch group were shorter than those in the goal-directed lactated Ringer's group and the restrictive lactated Ringer's group. No significant differences were found in the postoperative complications among the three groups.

CONCLUSION

Monitoring and minimizing pulse pressure variation by 6% hydroxyethyl starch solution (130/0.4) loading during gastrointestinal surgery improves postoperative outcomes and decreases the discharge time of patients who are graded American Society of Anesthesiologists physical status I/II.

An observational study fluid balance and patient outcomes in the Randomized Evaluation of Normal vs. Augmented Level of Replacement Therapy trial

OBJECTIVE

To examine associations between mean daily fluid balance during intensive care unit study enrollment and clinical outcomes in patients enrolled in the Randomized Evaluation of Normal vs. Augmented Level (RENAL) replacement therapy study.

DESIGN

Statistical analysis of data from multicenter, randomized, controlled trials.

SETTING

Thirty-five intensive care units in Australia and New Zealand.

PATIENTS

Cohort of 1453 patients enrolled in the RENAL study.

INTERVENTIONS

We analyzed the association between daily fluid balance on clinical outcomes using multivariable logistic regression, Cox proportional hazards, time-dependent analysis, and repeated measure analysis models.

MEASUREMENTS AND MAIN RESULTS

During intensive care unit stay, mean daily fluid balance among survivors was -234 mL/day compared with +560 mL/day among nonsurvivors (p < .0001). Mean cumulative fluid balance over the same period was -1941 vs. +1755 mL (p = .0003). A negative mean daily fluid balance during study treatment was independently associated with a decreased risk of death at 90 days (odds ratio 0.318; 95% confidence interval 0.24-0.43; p < .000.1) and with increased survival time (p < .0001). In addition, a negative mean daily fluid balance was associated with significantly increased renal replacement-free days (p = .0017), intensive care unit-free days (p < .0001), and hospital-free days (p = .01). These findings were unaltered after the application of different statistical models.

CONCLUSIONS

In the RENAL study, a negative mean daily fluid balance was consistently associated with improved clinical outcomes. Fluid balance may be a target for specific manipulation in future interventional trials of critically ill patients receiving renal replacement therapy.

[Volume replacement in intensive care medicine]

Volume substitution represents an essential component of intensive care medicine. The amount of fluid administered, the composition and the timing of volume replacement seem to affect the morbidity and mortality of critically ill patients. Although restrictive volume strategies bear the risk of tissue hypoperfusion and tissue hypoxia in hemodynamically unstable patients liberal strategies favour the development of avoidable hypervolemia with edema and resultant organ dysfunction. However, neither strategy has shown a consistent benefit. In order to account for the heavily varying oxygen demand of critically ill patients, a goal-directed, demand-adapted volume strategy is proposed. Using this strategy, volume replacement should be aligned to the need to restore tissue perfusion and the evidence of volume responsiveness. As the efficiency of volume resuscitation for correction of tissue hypoxia is time-dependent, preload optimization should be completed in the very first hours. Whether colloids or crystalloids are more suitable for this purpose is still controversially discussed. Nevertheless, a temporally limited use of colloids during the initial stage of tissue hypoperfusion appears to represent a strategy which uses the greater volume effect during hypovolemia while minimizing the risks for adverse reactions.

Fluids and gastrointestinal function

PURPOSE OF REVIEW

To highlight recent developments relating perioperative fluid therapy to gastrointestinal function by reviewing clinically pertinent English language articles mainly from January 2010 to March 2011.

RECENT FINDINGS

The control of fluid and electrolyte balance involves multiple processes in which the gastrointestinal tract plays an integral role. Diseases affecting the gastrointestinal tract commonly cause fluid and electrolyte disturbance. Similarly, intravenous fluid therapy in the perioperative period can affect gastrointestinal function and have a bearing on postoperative outcome. Striking a balance, in terms of both fluid composition and volume, is likely to reduce the morbidity associated with interstitial edema, a frequently observed occurrence with contemporary perioperative fluid regimens. This balance may be best achieved using individualized and goal-directed approaches to fluid therapy, in order to provide fluid when it is needed and in the correct quantities.

SUMMARY

In planning strategies of fluid therapy, the possibility of adverse effects on the gastrointestinal tract should be considered, as this is likely to have an impact on fluid and electrolyte balance and postoperative outcome.

Impact of remote ischemic preconditioning on wound healing in small bowel anastomoses

AIM: To investigate the influence of remote ischemic preconditioning (RIPC) on anastomotic integrity.

METHODS: Sixty male Wistar rats were randomized to six groups. The control group (n = 10) had an end-to-end ileal anastomosis without RIPC. The preconditioned groups (n = 34) varied in time of ischemia and time of reperfusion. One group received the amino acid L-arginine before constructing the anastomosis (n = 9). On postoperative day 4, the rats were re-laparotomized, and bursting pressure, hydroxyproline concentration, intra-abdominal adhesions, and a histological score concerning the mucosal ischemic injury were collected. The data are given as median (range).

RESULTS: On postoperative day 4, median bursting pressure was 124 mmHg (60-146 mmHg) in the control group. The experimental groups did not show a statistically significant difference (P > 0.05). Regarding the hydroxyproline concentration, we did not find any significant variation in the experimental groups. We detected significantly less mucosal injury in the RIPC groups. Furthermore, we assessed more extensive intra-abdominal adhesions in the preconditioned groups than in the control group.

CONCLUSION: RIPC directly before performing small bowel anastomosis does not affect anastomotic stability in the early period, as seen in ischemic preconditioning.