Patients Receiving Fluid Therapy Research Articles

Effect of subclavian vein diameter combined with perioperative fluid therapy on preventing post-induction hypotension in patients with ASA status I or II

BackgroundPerioperative hypotension is frequently observed following the initiation of general anesthesia administration, often associated with adverse outcomes. This study assessed the effect of subclavian vein (SCV) diameter combined with perioperative fluid therapy on preventing post-induction hypotension (PIH) in patients with lower ASA status.MethodsThis two-part study included patients aged 18 to 65 years, classified as ASA physical status I or II, and scheduled for elective surgery. The first part (Part I) included 146 adult patients, where maximum SCV diameter (dSCVmax), minimum SCV diameter (dSCVmin), SCV collapsibility index (SCVCI) and SCV variability (SCVvariability) assessed using ultrasound. PIH was determined by reduction in mean arterial pressure (MAP) exceeding 30% from baseline measurement or any instance of MAP < falling below 65 mmHg for ≥ a duration of at least 1 min during the period from induction to 10 min after intubation. Receiver Operating Characteristic (ROC) curve analysis was employed to determine the predictive values of subclavian vein diameter and other relevant parameters. The second part comprised 124 adult patients, where patients with SCV diameter above the optimal cutoff value, as determined in Part I study, received 6 ml/kg of colloid solution within 20 min before induction. The study evaluated the impact of subclavian vein diameter combined with perioperative fluid therapy by comparing the observed incidence of PIH after induction of anesthesia.ResultsThe areas under the curves (with 95% confidence intervals) for SCVCI and SCVvariability were both 0.819 (0.744–0.893). The optimal cutoff values were determined to be 45.4% and 14.7% (with sensitivity of 76.1% and specificity of 86.7%), respectively. Logistic regression analysis, after adjusting for confounding factors, demonstrated that both SCVCI and SCVvariability were significant predictors of PIH. A threshold of 45.4% for SCVCI was chosen as the grouping criterion. The incidence of PIH in patients receiving fluid therapy was significantly lower in the SCVCI ≥ 45.4% group compared to the SCVCI < 45.4% group.ConclusionsBoth SCVCI and SCVvariability are noninvasive parameters capable of predicting PIH, and their combination with perioperative fluid therapy can reduce the incidence of PIH.

Prolonged Exposure to Intestinal Edemagenic Stress Decreases Mesenteric Lymphatic Contractility

Mesenteric lymphatic vessels (MLVs) are the primary route for removal of excess intestinal interstitial fluid. Lymphatic pumping, the virtue of the intrinsic contractility of lymphatic muscle, is necessary for active lymph transport to the venous circulation and thus resolution of interstitial edema. Acute exposure to edemagenic stress has been reported to increase contractility and pumping of MLVs. However, our recent studies revealed that when exposure to edemagenic stress is prolonged, lymphatic contraction frequency decreases and pump failure ensues. It is unknown how the ability of lymphatic muscle to generate active tension is affected in these maladapted MLVs. Therefore, the purpose of the present study was to evaluate our hypothesis that prolonged exposure to edemagenic stress decreases lymphatic muscle contractility.Male Sprague Dawley rats underwent midline laparotomy with 3‐day exposure to either venous hypertension (VHT; induced by coarctation of superior mesenteric vein), fluid overload (HD; induced by daily IV infusion of 80 ml/kg lactated Ringer’s saline), or neither (SHAM; no additional intervention). In isometric biomechanics studies, MLVs were mounted on a wire myograph and perfused with warm APSS. Vessel rings were incrementally stretched, stimulated with substance P (1 µM) in 60 mM K+‐APSS (SP K‐APSS), followed by wash out with APSS. This sequence was repeated and the following steady state tensions were recorded at each level of stretch: unstimulated total tension (passive stretch, in APSS), stimulated total tension (SP K‐APSS), and passive tension (Ca++‐free APSS, at the end of the experiment). The circumferential length at the level of stretch yielding optimal delta tension (= stimulated total tension ‐ unstimulated total tension) for each vessel was identified as Lmax. Additionally, unstimulated active tension (= unstimulated total tension ‐ passive tension) and stimulated active tension (= stimulated total tension ‐ passive tension) were calculated.Vessels from VHT and SHAM groups yielded nearly identical length‐tension relationships. However, compared to SHAM and VHT vessels, HD vessels generated significantly lower tension across all indices: unstimulated total tension, stimulated total tension, passive tension, unstimulated active tension, and stimulated active tension. At optimal stretch (Lmax), the delta tension was lower in HD vessels than SHAM or VHT vessels.Consistent with findings of the previous studies, prolonged exposure to intestinal edemagenic stress induced mesenteric lymphatic pump failure in VHT and HD vessels. However, lymphatic muscle contractility was reduced only in HD vessels. Taken together, these findings suggest that peri‐ and post‐oprative fluid therapy in major surgery patients receiving fluid therapy may lead to mesenteric lymphatic maladaptation. The consequential decrease in intestinal lymph drainage would then contribute to delayed resolution of intestinal edema, increased morbidity and extended hospital stays.

Helicopter emergency medical services in East Azerbaijan province: assessment of patients’ outcome

In this study, we aimed to evaluate the outcomes of patients transported by Helicopter Emergency Medical Services in East Azerbaijan Province. This retrospective cross-sectional study was conducted on patients transported by the HEMS centre of Tabriz from August 2014 to March 2017. Records of the centre were used to collect data. Statistical analysis was performed by SPSS software version 20; the statistical significance level was considered below 0.05. In this study, 268 patients were transferred to Tabriz hospitals by 167 missions performed. The mean age of patients was 34.26±19.43, and 173 (65%) patients were male. The most common reason for call-out was the need for professional care (91.4%). The target of the majority of missions was on countryside routes. The mean distance of destinations was about 99.13±35.9 Kms, with a mean transference time of 54.68±14.17 minutes, while the mean estimated ground route time was 86.38±26.26 minutes. The most prevalent diagnosis was trauma; The Glasgow Coma Scale (GCS) and vital signs of the majority of patients were above 13 and stable, respectively. About 98 percent of patients received fluid therapy, and 71 percent were immobilized, and only 6 percent needed intubation. Also, 28 percent of patients needed Intensive Care Unit (ICU), 56 percent of whom passed away later. Our results suggest that Tabriz HEMS missions have reduced the patient transport time and also made the mortality rate closer to international standards.

Maintenance fluid therapy in a tertiary hospital: A prevalence study

Abstract Objective To assess the types of maintenance fluids used in our hospital, comparing their volume and composition to the standards recommended by the guidelines. Material and methods Observational, cross-sectional study. Volume and type of fluid therapy administered during 24 h to patients admitted to various hospital departments were recorded. Patients receiving fluid therapy because of water-electrolyte imbalance were excluded. Results Out of 198 patients registered, 74 (37.4%) were excluded because they did not meet the criteria for inclusion. Mean administered volume was 2500 cc/day. Mean daily glucose dose was 36 g per 24 h (SD: 31.4). The most frequent combination included normal saline solution (NSS) and glucose 5% (64.4%). Mean daily dose of sodium and chlorine was, respectively, 173 mEq (SD: 74.8) and 168 mEq (SD: 75), representing a surplus daily dose of +87.4 mEq and +85 mEq. Potassium, magnesium and calcium daily deficit was, respectively, −50 mEq, −22 mEq and −21 mEq per day. Buffer administration was exceptional, bicarbonate (2.29%), acetate (1.29%), lactate (1.15%) and gluconate (1.10%) being the buffering agents most frequently used. Conclusion NNS is the most frequently used solution. In contrast to excess doses of sodium and chlorine, there is a great deficit of other ions, buffering agents and caloric intake in the fluid therapy regimens that are usually prescribed.

Fluidoterapia de mantenimiento administrada en un hospital terciario: estudio de prevalencia

ObjectiveTo assess the types of maintenance fluids used in our hospital, comparing their volume and composition to the standards recommended by the guidelines. Material and methodsObservational, cross-sectional study. Volume and type of fluid therapy administered during 24h to patients admitted to various hospital departments were recorded. Patients receiving fluid therapy because of water-electrolyte imbalance were excluded. ResultsOut of 198 patients registered, 74 (37.4%) were excluded because they did not meet the criteria for inclusion. Mean administered volume was 2,500cc/day. Mean daily glucose dose was 36g per 24h (SD: 31.4). The most frequent combination included normal saline solution (NSS) and glucose 5% (64.4%). Mean daily dose of sodium and chlorine was, respectively, 173mEq (SD: 74.8) and 168mEq (SD: 75), representing a surplus daily dose of +87.4mEq and +85mEq. Potassium, magnesium and calcium daily deficit was, respectively, –50mEq, –22mEq and –21mEq per day. Buffer administration was exceptional, bicarbonate (2.29%), acetate (1.29%), lactate (1.15%) and gluconate (1.10%) being the buffering agents most frequently used. ConclusionNNS is the most frequently used solution. In contrast to excess doses of sodium and chlorine, there is a great deficit of other ions, buffering agents and caloric intake in the fluid therapy regimens that are usually prescribed.

Fluid Therapy Management in Hospitalized Patients: Results From a Cross-sectional Study

PurposeIntravenous (IV) fluid therapy is widely used in hospitalized patients. It has been internationally studied in surgical patients, but little attention to date has been dedicated to medical patients within the Italian context. The aims of the present study were to describe the prevalence of fluid therapy and associated factors among Italian patients admitted to medical and surgical units, describe the methods used to manage fluid therapy, and analyze the monitoring of patients by clinical staff. MethodsIn this cross-sectional study of 7 hospitals in northern Italy, data on individual and monitoring variables were collected, and their associations with in-hospital fluid therapy were analyzed by using logistic regression analysis. Patients aged ≥18 years who were admitted to medical and surgical units were included. Patients who received at least 500 mL of continuous fluids were included in the fluid therapy group. FindingsIn total, 785 (median age, 72 years; women, 52%) patients were included in the study, and 293 (37.3%) received fluid therapy. Maintenance was the most frequent reason for prescribing IV fluid therapy (59%). The mean (SD) volume delivered was 1177 (624) mL/d, and the highest volume was infused for replacement therapy (1660 [931] mL/d). The mean volume infused was 19.55 (13) mL/kg/d. The most commonly used fluid solutions were 0.9% sodium chloride (65.7%) and balanced crystalloid without glucose (32.9%). The proportion of patients assessed for urine output (52.6% vs 36.8%; P < 0.001), serum electrolyte concentrations (74.4% vs 65.0%; P = 0.005), and renal function (70.0% vs 58.7%; P = 0.002) was significantly higher in patients who did receive fluid therapy versus those who did not. In contrast, the use of weight and fluid assessments was not significantly different between the 2 groups (P = 0.216 and 0.256, respectively). Patients admitted for gastrointestinal disorders (odds ratio [OR], 3.5 [95% CI, 1.8–7.05) and for fluid/electrolyte imbalances (OR, 3.35 [95% CI, 1.06–10.52) were more likely to receive fluids. However, the likelihood of receiving fluids was lower for patients admitted to a surgical unit (OR, 0.36 [95% CI, 0.22–0.59]) and with cardiovascular diseases (OR, 0.37 [95% CI, 0.17–0.79). ImplicationsOnly one third of the study patients received fluid therapy. Crystalloid fluids, are the fluids of choice for maintaining plasma volume. During fluid therapy, measurement of the serum electrolyte concentrations, renal function, and urine output was largely used while weight and fluid balance were rarely assessed.

ROLES OF SO2 INDEX FOR PREDICTING OF FLUID RESPONSIVENESS IN HIGH RISK CARDIAC SURGICAL PATIENTS

Purpose: (1) Study the change in SO2 value in fluid therapy in patients after cardiac surgery; (2) Evaluate the role of SO2 monitoring in serving as an indicator of fluid responsiveness in patients after cardiac surgery. Methods: This was a prospective study reported earlier on critically ill patients with clinical hypovolemia after cardiac surgery. Fluid therapy was guided by changes in pulmonary artery wedge pressure or central venous pressure. Fluid responsiveness was defined as ≥15% increase in cardiac index. Hemodynamics, including left ventricular ejection fraction, cardiac index, and oxygen delivery were measured when SO2 blood samples taken. Results: There was 110 patients receiving fluid therapy in postoperative period. The SO2 increased in 104 patients responding to fluid loading (≥15% in cardiac index in n=107) versus those not responding (n=6). The increase in ejection fraction, cardiac index and oxygen delivery was also greater in responders (p=0.005). The area under the receiver operating characteristic curve for fluid responsiveness of changes in SO2 was 0.78 (p=0.05), with an optimal cutoff of 2%. The value of SO2 increased to reflect cardiac index increases with fluid loading was in 66.7% of patients. Conclusions: An increase in SO2 ≥ 2% can thus be used as an indicator of fluid responsiveness in clinically hypovolemic patients after cardiac surgery, particularly in those with systolic cardiac dysfunction. Fluid responsiveness concurs with increased tissue oxygen delivery. Key words: mixed venous oxygen saturation (SO2); oxygen delivery (DO2); oxygen consumption (VO2); central venous pressure (CVP), pulmonary artery wedge pressure (PAWP); cardiac index (CI); hypovolemia; fluid therapy.

Circulating tumour necrosis factor receptors 1 and 2 predict contrast-induced nephropathy and progressive renal dysfunction: a prospective cohort study.

Contrast-induced nephropathy (CIN) is an important cause of hospital-acquired acute kidney injury. An accurate understanding of the pathogenesis of CIN is crucial. The aim of this study was to evaluate the clinical role of circulating tumour necrosis factor receptors (cTNFRs) in CIN. From May 2013 to February 2014, 262 patients who underwent coronary angiography and/or percutaneous coronary intervention at Seoul National University Boramae Medical Center were enrolled. CIN was defined as either an increase in serum creatinine ≥ 22.1 μmol/L or ≥ 25% within 48 h after the procedure. Diabetes and chronic kidney disease accounted for 27.5% and 17.6% of the patients, respectively, and the mean age was 65 years. All patients received fluid therapy, and 36.3% underwent percutaneous coronary intervention. A total of 4.2% of the patients developed CIN; younger age, underlying diseases (e.g., stroke and chronic kidney disease), the use of N-acetylcysteine, and elevated concentrations of ln(cTNFRs) were associated with development of CIN. Increased values of ln(cTNFR1) (OR 6.32, 95% CI 2.46-16.28, P < 0.001) and ln(cTNFR2) (OR 3.24, 95% CI 1.26-8.31, P = 0.015) were significantly associated with CIN after adjusting for other risk factors, including baseline renal function. Moreover, an increase of cTNFRs levels was independently correlated with the deterioration of renal function. Markedly elevated concentrations of circulating TNFRs were correlated with the occurrence of CIN and significantly associated with prolonged renal dysfunction regardless of the development of CIN.

Four phases of intravenous fluid therapy: a conceptual model

I.V. fluid therapy plays a fundamental role in the management of hospitalized patients. While the correct use of i.v. fluids can be lifesaving, recent literature demonstrates that fluid therapy is not without risks. Indeed, the use of certain types and volumes of fluid can increase the risk of harm, and even death, in some patient groups. Data from a recent audit show us that the inappropriate use of fluids may occur in up to 20% of patients receiving fluid therapy. The delegates of the 12th Acute Dialysis Quality Initiative (ADQI) Conference sought to obtain consensus on the use of i.v. fluids with the aim of producing guidance for their use. In this article, we review a recently proposed model for fluid therapy in severe sepsis and propose a framework by which it could be adopted for use in most situations where fluid management is required. Considering the dose-effect relationship and side-effects of fluids, fluid therapy should be regarded similar to other drug therapy with specific indications and tailored recommendations for the type and dose of fluid. By emphasizing the necessity to individualize fluid therapy, we hope to reduce the risk to our patients and improve their outcome.

Impact of real-time electronic alerting of acute kidney injury on therapeutic intervention and progression of RIFLE class*

To evaluate whether a real-time electronic alert system or "AKI sniffer," which is based on the RIFLE classification criteria (Risk, Injury and Failure), would have an impact on therapeutic interventions and acute kidney injury progression. Prospective intervention study. Surgical and medical intensive care unit in a tertiary care hospital. A total of 951 patients having in total 1,079 admission episodes were admitted during the study period (prealert control group: 227, alert group: 616, and postalert control group: 236). Three study phases were compared: A 1.5-month prealert control phase in which physicians were blinded for the acute kidney injury sniffer and a 3-month intervention phase with real-time alerting of worsening RIFLE class through the Digital Enhanced Cordless Technology telephone system followed by a second 1.5-month postalert control phase. A total of 2593 acute kidney injury alerts were recorded with a balanced distribution over all study phases. Most acute kidney injury alerts were RIFLE class risk (59.8%) followed by RIFLE class injury (34.1%) and failure (6.1%). A higher percentage of patients in the alert group received therapeutic intervention within 60 mins after the acute kidney injury alert (28.7% in alert group vs. 7.9% and 10.4% in the pre- and postalert control groups, respectively, p μ .001). In the alert group, more patients received fluid therapy (23.0% vs. 4.9% and 9.2%, p μ .01), diuretics (4.2% vs. 2.6% and 0.8%, p μ .001), or vasopressors (3.9% vs. 1.1% and 0.8%, p μ .001). Furthermore, these patients had a shorter time to intervention (p μ .001). A higher proportion of patients in the alert group showed return to a baseline kidney function within 8 hrs after an acute kidney injury alert "from normal to risk" compared with patients in the control group (p = .048). The real-time alerting of every worsening RIFLE class by the acute kidney injury sniffer increased the number and timeliness of early therapeutic interventions. The borderline significant improvement of short-term renal outcome in the RIFLE class risk patients needs to be confirmed in a large multicenter trial.

Abstract 222: Administration of Intravenous Fluids in Patients Hospitalized with Heart Failure

Administration of Intravenous Fluids in Patients Hospitalized with Heart Failure Background: Administration of intravenous (IV) fluids to patients with acute decompensated heart failure (HF) may worsen pulmonary congestion or hemodynamic status. However, little is known about the use of IV fluids in clinical practice. We examined the frequency and volume with which commonly used IV fluid preparations are used among inpatients with HF as well as the association of these treatment patterns with diuretic use and length of stay (LOS). Methods: We identified all hospitalizations in 2009-2010 with a principal discharge diagnosis of heart failure from the Premier, Inc. hospitals. In order to capture inappropriate therapy with intravenous fluids, we limited our study period to the initial two days, a period during which most HF patients undergo diuresis for fluid overload. We excluded patients with a potential indication for fluid resuscitation (concomitant therapy with vasopressors or inotropes, undergoing invasive procedures, or having secondary diagnosis of bleeding, sepsis or anaphylaxis). We also excluded hospitalizations with age &lt; 18 yrs, &lt; 3 day LOS, transfer-ins, and hospitals with &lt; 25 HF cases. We calculated the administration frequency and volume of commonly used IV fluids (normal saline, half normal saline, 5% dextrose, and Lactated Ringer’s), the percentage of patients receiving concomitant therapy with loop diuretics, and the average LOS associated with administration of each of the four fluids. Results: Among 195,652 hospitalizations, 25% (48,611) were administered at least one of the four IV fluids. Normal saline was the most commonly administered fluid (19.4% of hospitalizations), followed by 5% dextrose (6%), half normal saline (2.2%), and Lactated Ringer’s (0.2%). The median volume of fluid administration over the first two days was 1,000 ml (IQR: 250, 1250). Eighty-nine percent of patients receiving fluid therapy received concomitant loop diuretics. Increasing median LOS was noted with increasing fluid volumes across all four individual IV fluid categories (see Table). Conclusion: A substantial proportion of patients hospitalized with HF receive a considerable volume of intravenous fluid during their first 2 hospital days; normal saline was the most commonly administered formulation. Loop diuretic use was very common in those receiving IV fluids. Greater understanding of the concomitant use of intravenous fluids and diuretics and their relation to length of stay may provide an opportunity to improve quality of care.

Early goal-directed therapy in severe acute pancreatitis

Objective To study the difference in outcomes between two treatment regimens of goal-directed fluid therapy in patients with severe acute pancreatitis. Methods From January 2000 to January 2010, 80 patients with severe acute pancreatitis were assigned into 2 groups. In group A,patients received fluid therapy aiming at the following goals in 24 hours: (1) Blood pressure >90/60 mm Hg;(2) CVP between 8-12 mm Hg;(3) Urine output >0. 5 ml · kg-1 · h-1. In group B, patients received fluid therapy aiming at the following goals in 6 hours (according to SSC guideline,2004): (1) mean arterial blood pressure >65 mm Hg;(2) CVP between 8-12 mm Hg;(3) Urine output >0. 5 ml · kg-1 · h-1 ;(4) central venous oxygen saturation >70%. After therapy for 3 days we measured the Marshall score, APACHE Ⅱ score, and the peri-pancreatic infection and mortality rates. Results The Marshall score was 6. 82±4. 69 and 4. 48±3. 78 in group A and B, respectively (P=0. 02). The APACHE Ⅱ score was 11. 35±5. 96 and 8. 22±4. 53 in group A and B, respectively (P=0. 01). The peri-pancreatic infection rate was 44% and 37% in group A and B, respectively, and there was no significant difference between the 2 groups (P = 0. 65). The mortality rate was 24% and 17% in group A and B. There was no significant difference between the 2 groups(P=0. 57). Conclusion Goal-directed fluid therapy in patients with severe acute pancreatitis according to the SSC guideline improved organ function but it did not reduce peri-pancreatic infection and mortality rates. Key words: Severe acute pancreatitis; Fluid therapy; Early goal-directed therapy; Marshall score; APACHE Ⅱ score

Does Central Venous Oxygen Saturation-directed Fluid Therapy Affect Postoperative Morbidity after Colorectal Surgery?

The optimal amount and method for monitoring intravenous fluid in surgical patients is unresolved. Central venous oxygen saturation (Scvo2) has been used to guide therapy and predict outcome in high-risk and intensive-care patients. The aim of this prospective, randomized trial was to compare the rate of postoperative complications in patients receiving fluid therapy guided by Scvo2 and those treated with a traditional effluent fluid scheme. Patients undergoing open colorectal and lower intestinal surgery (n = 241) were randomized to the Scvo2 group or the control group. The Scvo2 group received perioperatively crystalloid infusion 100 ml/h. When Scvo2 was less than 75%, a bolus of 3 ml/kg hydroxyethyl starch was given. The bolus was repeated if Scvo2 increased by 1 percentage point or more. The control group was maintained with crystalloid 800 ml/h and given extra fluid if there were clinical signs of hypovolemia. The participating surgeon, unaware of the group allocation, registered complications within day 30. Until 8:00 am on the first postoperative day, the Scvo2 group had received 3,869 ± 992 ml (mean ± SD) intravenous fluid compared with 6,491 ± 1,649 ml in the control group. Increase in weight was 0.8 ± 1.8 kg and 2.5 ± 1.6 kg in the two groups, respectively. The postoperative complication rate was 42% in both groups. Clinical outcomes among patients receiving Scvo2-guided perioperative fluid therapy were similar to those for patients treated with a traditional fluid regimen. Limitations in study design prevent full interpretation of these findings, and further large trials of this treatment algorithm are still required.

Correlation between Central Venous - Arterial Carbon Dioxide Tension Gradient and Oxygen Delivery Changes Following Fluid Therapy

Background: Central venous-arterial carbon dioxide (CVA-CO2) tension gradient was related to low cardiac output after coronary surgery. The objective of this study was to assess the correlation between CVA-CO2 tension gradient and oxygen delivery (DO2) changes following fluid therapy in coronary surgery. Methods: A prospective interventional study was conducted in a cardiac surgery intensive care unit. Forty consecutive sedated and mechanically ventilated adult patients, with a cardiac index < 2.3 L/min/m² and a pulmonary artery occlusion pressure ≤ 12 mmHg following coronary surgery, were included. All patients received a 500 ml bolus of an isotonic crystalloid solution over 20 min. Concomitant hemodynamic parameters, arterial and central venous blood gases were measured before (T0) and after (T1) volume loading. Means were compared by Student’s test and correlations by Spearmen coefficient”. P ≤ 0.05 was considered to be significant. Results: CVA-CO2 gradient decreased (12.6 ± 3.0 vs 10.2 ± 3.7 mmHg; p = 0.01) and DO2 increased (312 ± 57 vs 357 ± 81 l/min/m²; p = 0.001) significantly from T0 to T1. The correlation between CVA-CO2 gradient changes and DO2 changes was negative and statistically significant (r = -0.38; p=0.015). Conclusion: CVA-CO2 gradient and DO2 changes were inversely and significantly correlated in patients receiving fluid therapy following coronary surgery. In this context, CVA-CO2 gradient changes could be used as an indicator to guide volume loading and to assess its effect on DO2.

Correlation between central venous oxygen saturation and oxygen delivery changes following fluid therapy

The rationale for using central venous oxygen saturation (ScvO(2)) in various clinical scenarios is that it reflects the balance between oxygen delivery (DO(2)) and demands. In this study, we evaluated the correlation between ScvO(2) and DO(2) changes (Delta Do(2), DeltaScvO(2)) in patients receiving fluid therapy following coronary surgery. We also correlated the changes of mean arterial pressure (Delta MAP) and central venous pressure (Delta CVP), with Delta DO(2). Sixty consecutive sedated and mechanically ventilated adult patients, with cardiac index <or=2.3 L/min/m(2) and a pulmonary artery occlusion pressure <or=12 mmHg following coronary surgery, were included. Concomitant hemodynamic parameters, arterial and venous blood gases were measured before (T0) and after (T1) administration of a 500 ml bolus of an isotonic crystalloid solution over 30 min. The correlations between Delta DO(2) and DeltaScvO(2), Delta MAP or Delta CVP were evaluated by linear regression analysis and Pearson test. Cardiac index (1.9+/-0.2 vs 2.3+/-0.5 ml/min/m(2)), MAP (83+/-11 vs 94+/-13 mm Hg) and CVP (5.7+/-3 vs 7.1+/-3 mmHg) were significantly higher at T1 compared with T0. The correlation of Delta DO(2) with DeltaScvO(2) was positive, significant (r=0.41; P=0.004) and superior to its correlation with Delta MAP (r=0.30; P=0.01) or Delta CVP (r=0.03; P=0.78). A significant correlation between ScvO(2) and DO(2) changes was found in patients receiving fluid therapy following coronary surgery. ScvO(2) could be used as an indicator to track DO(2) and to guide volume loading.

Critically-ill patients receiving total parenteral nutrition show altered amikacin pharmacokinetics

The purpose of this clinical study was to characterise the kinetic behavior ofamikacin in the parenterally-fed critically-ill adult patient. 22 critically-ill adult patients treated with amikacin (15.5 ± 7.9 mg/kg/day) for severe gram-negative infections were enrolled into a nonrandomised control trial. Malnourished patients were administered total parenteral nutrition (TPN, n = 11), while well-nourished patients received fluid therapy (FT, n = 11). Amikacin pharmacokinetic parameters were estimated by non-linear regression analysis, assuming a one-compartment model and central first-order elimination. Patients receiving TPN showed an expanded amikacin distribution volume (0.403 ± 0.0961/kg vs. FT 0.298 ± 0.083 l/kg, p < 0.05), and a tendency towards increased total body clearance (0.089 ± 0.029 l/kg/h vs. FT 0.069 ± 0.0201/kg/h, p = 0.09). TPN produced lower peak concentrations (19.3 ± 3.1 mcg/ml vs. 23.1 ± 3.5 mcg/ml, p < 0.05), but had no significant influence on trough concentrations (p = 0.56). Patients on TPN also showed increased body temperature (p < 0.05) and fluid intake (p < 0.05), and decreased hematocrit (p < 0.05). Stress, malnutrition, parenteral nutrition itself, fluid and osmotic overload, and fever often occur concurrently in parenterally-fed patients and appear to produce lower amikacin serum levels. Consequently, critically-ill patients receiving TPN need higher amikacin doses and individualised treatment by monitoring serum concentrations, to ensure optimal therapeutic response.