Volume Of Fluid Administration Research Articles

Bioimpedance spectroscopy for assessment of volume status in patients before and after general anaesthesia.

BackgroundTechnically assisted assessment of volume status before surgery may be useful to direct intraoperative fluid administration. We therefore tested a recently developed whole-body bioimpedance spectroscopy device to determine pre- to postoperative fluid distribution.MethodsUsing a three-compartment physiologic tissue model, the body composition monitor (BCM, Fresenius Medical Care, Germany) measures total body fluid volume, extracellular volume, intracellular volume and fluid overload as surplus or deficit of ‘normal’ extracellular volume. BCM-measurements were performed before and after standardized general anaesthesia for gynaecological procedures (laparotomies, laparoscopies and vaginal surgeries). BCM results were blinded to the attending anaesthesiologist and data analysed using the 2-sided, paired Student’s t-test and multiple linear regression.ResultsIn 71 females aged 45±15 years with body weight 67±13 kg and duration of anaesthesia 154±68 min, pre- to postoperative fluid overload increased from −0.7±1.1 L to 0.1±1.0 L, corresponding to −5.1±7.5% and 0.8±6.7% of normal extracellular volume, respectively (both p<0.001), after patients had received 1.9±0.9 L intravenous crystalloid fluid. Perioperative urinary excretion was 0.4±0.3 L. The increase in extracellular volume was paralleled by an increase in total body fluid volume, while intracellular volume increased only slightly and without reaching statistical significance (p = 0.15). Net perioperative fluid balance (administered fluid volume minus urinary excretion) was significantly associated with change in extracellular volume (r2 = 0.65), but was not associated with change in intracellular volume (r2 = 0.01).ConclusionsRoutine intraoperative fluid administration results in a significant, and clinically meaningful increase in the extracellular compartment. BCM-measurements yielded plausible results and may become useful to guide intraoperative fluid therapy in future studies.

Fluid Restriction for Treatment of “Fluid Creep” after Acute Burn Resuscitation

Objective Fluid creep in patients recovering from acute burns still exists, despite the use of a more treatment conservative approach. Most of our severe burn patients develop fluid overload and body weight increase after acute fluid resuscitation. How to quickly return patients to their pre-injury body weight is an important issue. Methods Right after acute fluid resuscitation, we applied a “total fluid requirement” volume (usually 1/2 to 2/3 of initial 24 hour volume) and strictly monitored patients' hourly urine (between 0.5-1 ml/kg/hr). Patients' responses (body weight, enteric feeding amount, pulmonary condition, etc.) were also closely monitored and frequent adjustments of fluid volume administration were performed simultaneously. Results Most patients regained their pre-injury body weight within 2-3 weeks. Enteric feeding also improved markedly. No patients had severe oedema-related complications. Conclusions Stricter fluid administration after acute burn fluid resuscitation is advised for allowing patients to reduce body weight to their pre-injury weight or at least close to it. We use pre-injury body weight, enteric feeding and urine output as our guides. (Hong Kong j.emerg.med. 2014;21:222-229)

Subcutaneous Administration of Monoclonal Antibodies in Oncology.

Treatment with monoclonal antibodies (mabs) has become an established component of oncological therapy. The monoclonal antibodies available for this purpose are mainly administered intravenously in individually adapted doses according to body weight over longer treatment times. For other chronic diseases such as, for example, diabetes mellitus, the subcutaneous administration of drugs is an established therapy option. For the subcutaneous administration of larger volumes as needed for mab solutions the extracellular matrix of the subcutaneous tissue represents a problem. The co-formulation with recombinant human hyaluronidase makes the relatively pain-free administration of larger fluid volumes and thus the subcutaneous administration of monoclonal antibodies possible, as illustrated by the development of a subcutaneous formulation of trastuzumab. This constitutes a less invasive, time-optimised and flexible form of administration for patients with HER2-positive breast cancer that, with its fixed dosing possibilities, contributes to therapeutic safety. The example of trastuzumab shows that the subcutaneous administration of monoclonal antibodies can simplify oncological long-term therapy not only for the patients but also for the medical personnel.

The Effect of Intraoperative Fluid Volume Administration on Pancreatic Fistulas after Pancreaticoduodenectomy

ABSTRACTBackground: Fluid therapy may be one of the most controversial topics in perioperative management. However, data concerning the influence of perioperative fluid administration on complications after pancreaticoduodenectomy are sparse. Methods: A group of 147 patients underwent pancreaticoduodenectomy for benign or malignant pathology of the pancreas or the periampullary region between 2005 and 2009. Clinical data, overall morbidity, and long-term outcomes were recorded. Results: We categorized the patients into two groups according to intraoperative fluid volume administration: a low fluid volume group (LFVG, <8.2 ml kg−1 hr−1, n = 90) group, and a high fluid volume group (HFVG, ≥8.2 ml kg−1 hr−1, n = 57). In terms of colloid administration, the high fluid volume group received significantly more colloid both during the intraoperative period and 0–12 hr after surgery (p < .001 and p < .007, respectively). Pancreatic fistula rates were significantly greater in the high fluid volume group (p = .035). However, the long-term survival rate was not different between the two groups. Conclusions: High intraoperative fluid volume administration is associated with an increased incidence of pancreatic fistulas after pancreaticoduodenectomy.

Goal-directed fluid optimization based on stroke volume variation and cardiac index during one-lung ventilation in patients undergoing thoracoscopy lobectomy operations: a pilot study

OBJECTIVES:This pilot study was designed to utilize stroke volume variation and cardiac index to ensure fluid optimization during one-lung ventilation in patients undergoing thoracoscopic lobectomies.METHODS:Eighty patients undergoing thoracoscopic lobectomy were randomized into either a goal-directed therapy group or a control group. In the goal-directed therapy group, the stroke volume variation was controlled at 10%±1%, and the cardiac index was controlled at a minimum of 2.5 L.min-1.m-2. In the control group, the MAP was maintained at between 65 mm Hg and 90 mm Hg, heart rate was maintained at between 60 BPM and 100 BPM, and urinary output was greater than 0.5 mL/kg-1/h-1. The hemodynamic variables, arterial blood gas analyses, total administered fluid volume and side effects were recorded.RESULTS:The PaO2/FiO2-ratio before the end of one-lung ventilation in the goal-directed therapy group was significantly higher than that of the control group, but there were no differences between the goal-directed therapy group and the control group for the PaO2/FiO2-ratio or other arterial blood gas analysis indices prior to anesthesia. The extubation time was significantly earlier in the goal-directed therapy group, but there was no difference in the length of hospital stay. Patients in the control group had greater urine volumes, and they were given greater colloid and overall fluid volumes. Nausea and vomiting were significantly reduced in the goal-directed therapy group.CONCLUSION:The results of this study demonstrated that an optimization protocol, based on stroke volume variation and cardiac index obtained with a FloTrac/Vigileo device, increased the PaO2/FiO2-ratio and reduced the overall fluid volume, intubation time and postoperative complications (nausea and vomiting) in thoracic surgery patients requiring one-lung ventilation.

Perioperative fluid therapy in elective colectomy in an enhanced recovery programme

Although intraoperative fluid restriction is thought to provide clinical benefits, it may not be suitable for patients with significant co-morbidities, who may ultimately require greater amounts of intravenous fluid (IVF) post-operatively. This study investigates whether intraoperative fluid restriction can be implemented uniformly in patients undergoing elective colectomy within an Enhanced Recovery after Surgery (ERAS) protocol and investigates the association between fluid administration and clinical outcomes. A retrospective review of prospectively collected data was conducted for all patients who underwent elective colectomy from September 2006 to 2010 within our ERAS programme. Patients received intraoperative fluid restriction with post-operative fluid administered as per clinical indications. Demographic data, American Society of Anaesthesiology (ASA) status, IVF administered and clinical outcomes were recorded. There were 227 patients (ASA 1: 47; ASA 2: 108; ASA 3: 72) with a median age of 71 years. Patients received a median of 2000 mL of crystalloid intraoperatively. There were no statistically significant differences between post-operative IVF amounts. Patients who experienced complications received significantly greater amounts of IVF post-operatively (5000 mL versus 2000 mL; P < 0.01) and post-operative IVF administration was the strongest predictor of complications in a logistic regression model. There was a trend suggesting higher median post-operative IVF prior to patients experiencing major complications (3000 mL versus 2000 mL; P= 0.07). Intraoperative fluid restriction can be employed uniformly in ASA 1-3 patients undergoing colectomy. Post-operative administration of greater fluid volumes was associated with adverse outcomes.

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.

The Alfred pre-hospital fluid formula for major burns

Background The Alfred pre-hospital fluid isotonic crystalloid resuscitation formula for major burns (body weight (kg) × %TBSA burnt = mls in the first 2 h) was adopted by Ambulance Victoria in 2007 for the early and consistent correction of fluid deficit in major burns patients. The aim of this study was to evaluate the associated change in pre-hospital fluid administration. Methods A retrospective explicit chart review of patient records was conducted of all patients with major burns presenting to The Alfred Emergency & Trauma Centre over a 10 year period. Patient demographics, fluid resuscitation and outcomes in the period before the introduction of the new formula were compared to those in the post-introduction period. Results There were 126 patients with major burns (≥20% total body surface area burnt) included in the study. The median fluid volume administration pre-hospital after introduction of The Alfred formula was 0.35 (0.22–0.44) mL/kg/%TBSA burnt, which was significantly higher than 0.14 (0.04–0.26) mL/kg/%TBSA administered in the prior period ( p = 0.013). There was no significant change in physiological endpoints associated with the increased volume. At 24 h, the volume of fluid administered in patients when The Alfred formula was used was 4.9 ± 1.6 mL/kg/%TBSA, which was not significantly higher than the volume administered before 2007 of 4.8 ± 2.2 mL/%TBSA/kg ( p = 0.802). Discussion The Alfred pre-hospital fluid formula has resulted in patients receiving significantly more fluids early, although still below volumes suggested by the Parkland formula. There were no adverse effects of this increased volume detected over the study period. The Alfred pre-hospital fluid formula appears to be safe and more effective in delivering fluid volumes predicted by the current ‘gold standard’.

Burn Resuscitation

Fluid resuscitation following burn injury must support organ perfusion with the least amount of fluid necessary and the least physiological cost. Under resuscitation may lead to organ failure and death. With adoption of weight and injury size-based formulas for resuscitation, multiple organ dysfunction and inadequate resuscitation have become uncommon. Instead, administration of fluid volumes well in excess of historic guidelines has been reported. A number of strategies including greater use of colloids and vasoactive drugs are now under investigation to optimize preservation of end organ function while avoiding complications which can include respiratory failure and compartment syndromes. Adjuncts to resuscitation, such as antioxidants, are also being investigated along with parameters beyond urine output and vital signs to identify endpoints of therapy. Here we briefly review the state-of-the-art and provide a sample of protocols now under investigation in North American burn centers.

Controlled Hypotension in Patients Suspected of a Ruptured Abdominal Aortic Aneurysm: Feasibility during Transport by Ambulance Services and Possible Harm

Objective To evaluate a controlled hypotension protocol for patients suspected of a ruptured aneurysm of the abdominal aorta (RAAA) and to identify possible harm to patients with a final diagnosis other than RAAA. Design Retrospective analysis of patients suspected of RAAA and transported by Amsterdam ambulance services between January 2006 and October 2007. Patients and methods Protocol was assessed by reviewing systolic blood pressure (<80 mmHg, 80–100 mmHg or >100 mmHg), administered fluid volume and verbal responsiveness during transport. Patients who could possibly have been harmed by controlled hypotension were identified by final diagnoses. Results Fluid administration was according to protocol in 220 of 266 patients analysed for protocol adherence. The remaining patients received too much (21 patients) or too little fluid (25 patients). Data were missing in 29 patients. A RAAA was diagnosed in 81 (27%) of all 295 patients analysed for final diagnosis. Controlled hypotension was achieved in 10% of all patients and in 17% of patients with RAAA. Three patients (1%) with diagnosis other than RAAA were possibly at risk by implementing controlled hypotension. Conclusions Protocol was followed in 83% and protocol violations occurred in 17% of patients. The risk of implementing controlled hypotension for all patients suspected of an RAAA by the ambulance staff was low.

Neurogenic Bladder

We describe the case of a 73-year-old woman with a history of chronic low back pain and 2 previous lumbar fusions who presented with complaints of worsening back and leg pain. Having previously undergone multiple interventions, physical therapy, and oral analgesics with limited pain relief, the patient opted for endoscopic lysis of adhesions for severe scarring of the epidural space. Subsequently, the patient developed a neurogenic bladder with urinary retention. Three years later, she experienced resolution of the neurogenic bladder symptoms that coincided with the use of the antibiotic nitrofurantoin. Upon discontinuation of the antibiotic, the patient noted that she was unable to void spontaneously. With reinstitution of nitrofurantoin, the patient was once again able to void effectively and has been maintained on nitrofurantoin for >3 years.

Glucose as a Marker of Fluid Absorption in Bipolar Transurethral Surgery

Historically, a reduced serum sodium concentration has been used to diagnose absorption of electrolyte-free irrigating fluid during transurethral resection of the prostate (TURP). In bipolar TURP, the irrigating solution contains electrolytes, thus invalidating the serum sodium method. In this study, we investigated whether glucose can be used to diagnose the absorption of irrigating fluid during TURP procedures. The serum glucose and sodium concentrations were measured in 250 patients undergoing monopolar TURP using either 1.5% glycine or 5% glucose for urinary bladder irrigation. The glucose kinetics was analyzed in 10 volunteers receiving a 30-min infusion of 20 mL/kg of acetated Ringer's solution with 1% glucose. These data were then used in computer simulations of different absorption patterns that were summarized in a nomogram for the relationship between the glucose level and administered fluid volume. There was a statistically significant inverse linear relationship between the decrease in serum sodium and the increase in glucose levels after absorption of 5% glucose during TURP (r(2) = 0.80). The glucose concentration increased, from 4.6 (sd 0.4) to 8.3 (0.9) mmol/L, during the experimental infusions. Regardless of the absorption pattern, all simulations indicated that the uptake of 1 L of fluid containing 1% glucose corresponded to an increase in the glucose level of 3.7 (sd 1.6) mmol/L at the end of surgery, whereas 2 L yielded an increase of 6.9 (1.7) mmol/L. In bipolar TURP, the addition of glucose to a concentration of 1% in the electrolyte-containing irrigation fluid can be used as a tracer of absorption that is comparable with measuring serum sodium after monopolar TURP.

Administration of large fluid volumes decreases the incidence of postoperative nausea and vomiting as effectively as ondansetron.

The possibility that large fluid volumes reduce postoperative nausea and vomiting (PONV) remains unclear due to conflicting data. We examined if administering large fluid volumes to high risk patients would decrease the incidence of PONV and compared the results with ondansetron administration. Ninety ASA I, II patients who presented for laparoscopic cholecystectomy were randomized to 1 of 3 groups. They received either (group I) 5 ml/kg/hr of Hartmann's solution, (group II) 30 ml/kg/hr of Hartmann's solution or (group III) 4 mg of ondansetron and 5 ml/kg/hr of Hartmann's solution. The incidence of PONV and severity of pain were assessed at 1, 12 and 24 hours postoperatively. The number of PONV episodes was significantly reduced in group II and III compared to group I during the 1-12 hr postoperative period and for total incidence. However, there was no significant difference between group II and III. There were no differences among groups regarding the severity of pain. Intraoperative correction of intravascular volume deficits with 30 ml/kg/hr of Hartmann's solution decreases the incidence of PONV as effectively as administration of ondansetron.

Is Fluid Therapy Associated With Cerebral Edema in Children With Diabetic Ketoacidosis?

Diabetic ketoacidosis is the most common cause of morbidity and mortality in children with type I diabetes mellitus, and cerebral edema is the leading cause of pediatric diabetic ketoacidosis death. Excessive intravenous fluid administration has been implicated as a cause of cerebral edema. We perform an evidence-based emergency medicine review assessing the association of intravenous fluid hydration and cerebral edema. We searched MEDLINE and EMBASE for comparative studies. Because of the low incidence of cerebral edema, we included observational studies in our review. We sought studies including patients younger than 18 years and with diabetic ketoacidosis. We defined cerebral edema, using clinical, radiographic, pathologic criteria, or treatment for intracranial pressure. Three studies met criteria for this review, of which 2 used fluid volume/body weight per unit of time, and the third measured cumulative total volume during hourly periods. The first 2 studies showed no statistically significant association between intravenous fluid administration and cerebral edema. The third study showed a significant association (odds ratio 6.55; 95% confidence interval 1.38 to 30.97) between the total volume (uncorrected for body weight) of infused fluid and the risk of cerebral edema. Accepting the inherent limitations of observational studies, we found a lack of strong or consistent results implicating rate or volume of fluid administration as a precipitant cause of cerebral edema in patients with diabetic ketoacidosis.

Management of Fluid Balance in Continuous Renal Replacement Therapy: Technical Evaluation in the Pediatric Setting

Fluid overload control and fluid balance management represent very important factors in critically ill children requiring renal replacement therapy. A relatively high fluid volume administration in children and neonates is often necessary to deliver adequate amounts of blood derivatives, vasopressors, antibiotics, and parenteral nutrition. Fluid balance errors during pediatric continuous renal replacement therapy (CRRT) might significantly impact therapy delivery and have been described as potentially lethal. The aim of this study was to evaluate the accuracy of delivered vs. prescribed net ultrafiltration (UF) during CRRT applied to 2 neonates and 2 small children, either as dialytic treatment alone or during extracorporeal membrane oxygenation (ECMO). In accordance with an Acute Dialysis Quality Initiative workgroup statement, net UF was defined as the ""overall amount of fluid extracted from the patient in a given time"". Mean prescribed net UF was 18.5 ml/h (SD=6.7) during neonatal treatments and 70.3 ml/h (SD=22.5) during CRRT in small children. Daily net UF ranged from 200 mL to about 600 mL in the 2 neonates and from 1,200 to 1800 mL in the 2 children. The percentage error of delivered net UF ranged from -1.6% to 5.8% of the prescribed level. The mean error of the ECMO/CRRT patients was 3.024 ml/h vs. 0.45 m/h for the CRRT patients (p<0.001). The same difference was not evident when the 2 neonates were compared with the 2 small children (without considering the presence of ECMO). CRRT and net UF delivery appeared to be accurate, safe, and effective in this small cohort of high-risk pediatric patients.

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

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. 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. 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. 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.

Nitrous oxide for monitoring fluid absorption in volunteers

We studied whether nitrous oxide (N(2)O) added to a fluid allows the infused volume to be quantified by measuring N(2)O in the expired air during normal breathing. If so, N(2)O might serve as a tracer of fluid absorption during endoscopic surgery. Twelve male volunteers received continuous and intermittent i.v. infusions (5-45 min) of fluid containing 40 ml litre(-1) of N(2)O. Breath N(2)O and CO(2) concentrations were measured every second via a flared nasal cannula, a standard nasal cannula, or a Hudson mask. An expression for the amount of infused fluid was obtained by calculating the area under the N(2)O concentration-time curve for samples representative for exhalation (CO(2)>median) and then dividing this area by the median CO(2) for the remaining samples. The N(2)O method then estimated fluid volumes of between 50 and 1400 ml within a 95% prediction interval of +/-200 ml. There were differences of up to 14% in results between the airway devices tested, but the volunteers preferred the flared nasal cannula. N(2)O showed a distinctly higher 3 min variability during intermittent infusion, which could indicate whether fluid absorption is directly intravascular or extravascular. No adverse effects were seen. N(2)O method does not require forced end-expiratory breath sampling but still predicts an administered fluid volume with high precision. N(2)O variability can probably be used to distinguish immediately between intravascular and perivesical fluid absorption during surgery.

Anti-Xa activity after subcutaneous administration of dalteparin in ICU patients with and without subcutaneous oedema: a pilot study

IntroductionIntensive care unit (ICU) patients often suffer from subcutaneous oedema, due to administration of large fluid volumes and the underlying pathophysiological condition. It is unknown whether the presence of subcutaneous oedema impairs the absorption of dalteparin, a low molecular weight heparin, when it is given by subcutaneous administration for venous thromboembolism prophylaxis. The objective of this study is to compare the anti-Xa activity of dalteparin after subcutaneous administration in ICU patients with and without subcutaneous oedema.MethodsThis non-randomized open parallel group follow-up pilot study was conducted in two mixed medical-surgical intensive care units at two teaching hospitals. Seven ICU patients with subcutaneous oedema (index group) and seven ICU patients without subcutaneous oedema (reference group) were studied. Anti-Xa activity was determined at 0, 3, 4, 6, 8, 12 and 24 hours after subcutaneous administration of 2,500 IU dalteparin. Plasma concentrations of factor anti-Xa activity were measured using a chromogenic factor Xa inhibition assay.ResultsThe characteristics of the index group were: age, 58 years; male/female ratio, 5/2; body mass index at admission, 23.4 kg/m2 (at study day, 30.6 kg/m2). The characteristics of the reference group were: age, 49 years; male/female ratio, 6/1; body mass index at admission, 24.8 kg/m2 (at study day, 25.0 kg/m2). In the index group, creatinine clearance was lower compared to the reference group (71 versus 131 ml/minute, p = 0.003). Sequential organ failure assessment score did not differ between index and reference groups (4 versus 5). Mean arterial pressure was comparable between index and reference groups (91 versus 95 mmHg) and within the normal range. The mean Cmax value was not different between ICU patients with and without subcutaneous oedema (0.15 ± 0.02 versus 0.14 ± 0.02 IU/ml, p = 0.34). In the index group, the mean AUC(0–24 h) value was slightly higher compared with the reference group (1.50 ± 0.31 versus 1.15 ± 0.25 h·IU/ml, p = 0.31). This difference was not significant.ConclusionIn this pilot study, there was no clinically relevant difference in anti-Xa activity after subcutaneous administration of 2,500 IU dalteparin for venous thromboembolism prophylaxis between ICU patients with and without subcutaneous oedema. Critically ill patients seem to have lower anti-Xa activity levels than healthy volunteers.

CVP and PAoP Measurements Are Discordant During Fluid Therapy After Traumatic Brain Injury

The objective of the study was to compare measurements of central venous pressure (CVP) and pulmonary artery occlusion pressures (PAoP) as estimates of intravascular volume during the first 96 hours of fluid therapy after traumatic brain injury (TBI). One thousand five hundred ten simultaneous CVP and PAoP measurements from 31 patients entered into the National Acute Brain Injury Study: Hypothermia (NABISH:H) protocol were retrospectively compared. The effect of fluid administration and body temperature upon the paired measurements was statistically assessed. Agreement between CVP and PAoP values was poor. The CVP and PAoP were equal in only 11% of paired values. The CVP was always higher than PAoP in 1 patient, whereas PAoP always exceeded the CVP in 5 others. In 74% of the pairs, the PAoP was higher than the CVP, whereas in 15%, CVP was greater than PAoP. For any CVP measurement, the PAoP was either 3 mm Hg above or below the CVP in 67% of the pairs and at least 5 mm Hg above or below the CVP in 21% of the pairs. In 21 (68%) patients, PAoP was > or = 5 mm Hg above CVP in more than 4 readings, a clinically important difference. Discordance was not attributed to the fluid administered or to the temperature protocol. Neurological outcome appears affected by the volume of fluid administration. However, during initial therapy, estimates of intravascular volume provided by the CVP and PAoP are discordant. Although documented in other clinical conditions, the disparity noted here after TBI has not been previously reported. Assessment of intravascular volume to avoid hypovolemia should utilize other measurement techniques.

Acute Deafness After Spinal Anesthesia

We report a case of acute deafness after spinal anesthesia. CASE REPORT A seventy six year old patient received for a total knee replacement a combined spinal and epidural lumbar anesthesia at the height L 3⁄4. She got 3,5 ml bupivacaine 0,5% intrathecal; the epidural catheter was put in 15 cm from skin level. Neurological diseases or hearing defects weren't listed in case history. Within two hours the surgery was practiced without difficulties. Following the surgery a Patient Control Analgesia (PCA) – pump administering 4 ml ropivacaine 0,2%/h was connected to the epidural catheter. Additionally, the patient was able to receive boli of 5 ml ropivacaine 0,2% all 30 minutes at most. Due to the above mentioned therapy the patient was painless and no complications took place. After an increased mobilization out of bed starting at the 4 th postoperative day the patient suddenly complained about severe unilateral deafness. 15 hours later she also complained about a headache reinforcing in upright position. Due to frequent bolus requirements of app. 10 ml ropivacaine 0,2% (20 mg) by the patient during several days the unilateral deafness was explained as a central sign of overdosing the ropivacaine. As a result the PCA – pump was taken away. During four days the patient got app. 400 mg of ropivacaine a day up until that point of time. The thought of a possible complication concerning the spinal anesthesia wasn't taken into account until a position – related headache appeared. Within five days the hearing ability recovered very well and on account of the administration of dipyrone the headache vanished after two days. DISCUSSION In medical literature temporary unilateral deafness of the inner ear is discussed as a controversial complication following spinal anesthesia. Thus, Panning [4] sees no need for a patient to be routinely enlightened about the risk of temporary deafness prior to spinal anesthesia due to the low incidence of that particular complication. Dreyer, however, conducted a prospective study which projects an incidence rate of 16% a frequency which would make patient enlightenment about potential postoperative deafness mandatory. The unilateral deafness described in Dreyer`s publication appeared on the second day after spinal anesthesia and disappeared three days later without any therapy. The unilateral deafness, which usually concerns typically the low and the medium frequencies, is attributed to a decreased pressure in the subarachnoid space due to a loss of liquor [2]. This results in a modification of the endolymphatic pressure difference and therefore triggers a change in the oscillatory characteristics of the basilar membrane. Another study-group examined the incidence of temporary deafness following general and spinal anesthesia. They concluded that the intraoperatively administered fluid volume played a key role whereas the anesthesiological procedure itself could not be established as a contributing factor []. Constantinidis [1] et al. present a case with unilateral cochlear dysfunction and sensorineural hearing loss after inguinal hernia operation under controlled anesthesia. Acute Deafness After Spinal Anesthesia 2 of 3 According to Constantinidis [] at al., however, spinal anesthesia seems to generate a higher incidence of acute unilateral deafness. In that respective case, unilateral deafness did not appear until the fourth postoperative day. As a consequence, the physicians in charge did not instantly attribute this symptom to the spinal puncture. They rather considered it to be a side effect of the continuously administered local anesthetic. It was not until the onset of a typical postspinal headache and the persistence of unilateral deafness after discontinuation of the local anesthetic that a loss of liquor was considered as a potential cause. The fact that the symptoms occurred four days after surgery can be explained by the protracted immobilization of the patient, which made it impossible for the patient to assume an upright position to sit or walk. Our case indicates that the possibility of a loss of liquor has to be taken into account even in a case of delayed postoperative partial deafness. Another interesting point is, that hearing loss developing after spinal anesthesia is more frequent and severe in the young than in the elderly patients [3]. In this study it is again hypothesized that the cerebrospinal fluid leakage after dural puncture plays an important role regarding the developing of a hearing loss after spinal anesthesia. Additionally, it has to be emphasized that temporary unilateral deafness can be regarded a not uncommon complication few doctors seem to be aware of. Further studies need to answer the following question: Is unilateral deafness only a result of spinal anesthesia or can this complication also be attributed to general anesthesia? Divergent opinions regarding this issue seem to prevail in current medical literature. CORRESPONDENCE TO Peter Lierz, M.D, Department of Anesthesiology, Pain Control and Critical Care Medicine Marienkrankenhaus Soest Widumgasse 5 D-59494 Soest Soest, Germany, Europe Tel: +49-2921-3911201 Fax: +49-2921-3911209 Email: dr.lierz@marienkrankenhaus-soest.de