Ringer's Acetate Solution Research Articles

The ideal crystalloid – what is ‘balanced’?

This review explores the contemporary definition of the term 'balanced crystalloid' and outlines optimal design features and their underlying rationale. Crystalloid interstitial expansion is unavoidable, but also occurs with colloids when there is endothelial glycocalyx dysfunction. Reduced chloride exposure may lessen kidney dysfunction and injury with a possible mortality benefit. Exact balance from an acid-base perspective is achieved with a crystalloid strong ion difference of 24 mEq/l. This can be done simply by replacing 24 mEq/l of chloride in 0.9% sodium chloride with bicarbonate or organic anion bicarbonate substitutes. Potassium, calcium and magnesium additives are probably unnecessary. Large volumes of mildly hypotonic crystalloids such as lactated Ringer's solution reduce extracellular tonicity in volunteers and increase intracranial pressure in nonbrain-injured experimental animals. A total cation concentration of 154 mmol/l with accompanying anions provides isotonicity. Of the commercial crystalloids, Ringer's acetate solution is close to balanced from both acid-base and tonicity perspectives, and there is little current evidence of acetate toxicity in the context of volume loading, in contrast to renal replacement. The case for balanced crystalloids is growing but unproven. A large randomized controlled trial of balanced crystalloids versus 0.9% sodium chloride is the next step.

Preoperative oral rehydration solution intake volume does not affect relative change of mean arterial blood pressure and crystalloid redistribution during general anesthesia in low-risk patients: an observational cohort study

Despite the implementation of liberal preoperative fasting routines, it is unclear whether preoperative oral rehydration solution intake volume affects blood pressure during general anesthesia. We enrolled 60 patients (American Society of Anesthesiologists status I/II) undergoing tympanoplasty. Patients drank 200-1,000 ml oral rehydration solution until 2-3 h before anesthesia induction. Anesthesia was induced by propofol and maintained with sevoflurane and remifentanil. Coinciding with anesthesia induction, 15 ml/kg Ringer's acetate solution was administered intravenously over 60 min followed by 1 ml/kg Ringer's acetate solution over the next 30 min. Mean arterial blood pressure (MAP) and whole-body bioelectrical resistance for extracellular fluid (R e) during anesthesia were compared between retrospectively classified intake groups of oral rehydration solution. There were no differences in mean MAP during the 30-90 min period relative to baseline [0.67 (0.60-0.74), 0.65 (0.61-0.76), 0.64 (0.60-0.70), P = 0.96] and relative R e at 90 min [0.945 (0.018), 0.944 (0.021), 0.943 (0.021), P = 0.95] between the small (n = 14), intermediate (n = 29), and large (n = 17) intake groups. The intake volume of preoperative oral rehydration solution does not affect the magnitude of hypotension during general anesthesia in low-risk patients undergoing minor surgery.

Unusual clinical course of preeclampsia heralded by generalized edema

Preeclampsia monitored by the amount of proteinuria usually does not show amelioration during pregnancy. A 37-year-old nulliparous woman was admitted to our hospital at gestational week (GW) 24(-1/7) due to rapid weight gain (6.2 kg/4 weeks) and oligohydramnios. Hypertension (151/91 mmHg) appeared at GW 25(-0/7) and proteinuria not detected at GW 24(-0/7) became significant (0.55 g/day) at GW 25(-2/7) . During the 2 successive weeks after administration of betamethasone at 12 mg twice and transabdominal amnioinfusion with 250 mL of Ringer's acetate solution at GW 25(-3/7) , generalized edema, proteinuria and thrombocytopenia markedly improved: bodyweight, 78.0 to 69.0 kg; proteinuria, from 7.1 to 1.3 g/day; and platelet count, from 111 to 230 × 10(9) /L. However, intrauterine infection accompanied by non-reassuring fetal status necessitated emergency cesarean section at GW 28(-3/7) . Extraordinary bodyweight gain can herald the occurrence of preeclampsia and this weight gain together with signs of preeclampsia can ameliorate even during pregnancy, although its mechanism is unclear.

Comparison Between D901 Lilliput 1 and Kids D100 Neonatal Oxygenators: Toward Bypass Circuit Miniaturization

Progress in biomaterial technology and improvements in surgical and perfusion strategy ameliorated morbidity and mortality in pediatric cardiac surgery. In this study, we describe our clinical experience comparing performance of two neonatal oxygenators. From January 2002 to March 2011, 159 infants with less than 5 kg body weight underwent heart surgery. Ninety-four patients received a D901 Lilliput 1 oxygenator with standard bypass circuit (group A), while 65 received a D100 Kids with miniaturized bypass circuit (group B). Miniaturization consisted in shortened arterial, venous, cardioplegia, and pump-master lines. Priming composition consisted in Ringer's acetate solution with addition of albumin and blood, with target hematocrit of 24% or greater. In group B cardiopulmonary bypass (CPB) was vacuum-assisted and started with an empty venous line. Modified ultrafiltration and Cell-Saver blood infusion was routinely applied in both groups. Average ± standard deviation (SD) age at repair was 37 ± 38 days in group A and 59 ± 60 days in group B (P = 0.005). Average ± SD weight, height, and body surface area were 3.5 ± 0.7 kg, 52 ± 4 cm, and 0.22 ± 0.03 m(2) , respectively, in group A, and 3.7 ± 1 kg, 53 ± 5 cm, and 0.23 ± 0.02 m(2) , respectively, in group B (P = not significant [NS]). Male sex was predominant (55 vs. 58%, P = NS). Priming volume was 524 ± 67 mL (group A) and 337 ± 53 mL (group B) (P = 0.001). There were no statistical differences in hemoglobin at the start, during, and at the end of CPB, but group A required higher blood volume added to the prime (111 ± 33 vs. 93 ± 31 mL, P = 0.001). In group B, two surgical procedures were completed in total hemodilution. In group B, CPB time and aortic cross-clamp time were shorter than in group A (106 ± 52 vs. 142 ± 78 min and 44 ± 31 vs. 64 ± 31 min, respectively, P = 0.001). There were 16 hospital deaths in group A and 4 in group B (P = 0.04). Durations of mechanical ventilation and intensive care unit stay were 5.3 ± 3.2 vs. 4.1 ± 3.2 days (P = 0.02) and 6.5 ± 4.9 vs. 5.1 ± 3 days (P = 0.03), respectively. There were significant differences in inotropic score (1083 ± 1175 vs. 682 ± 938, P = 0.04) and blood postoperative transfusion (153 ± 226 vs. 90 ± 61 mL, P = 0.04). Twenty-seven patients in group A and 10 in group B presented with major adverse postoperative complications (P = 0.04). Use of neonatal oxygenators with low priming volume, associated with a miniaturized bypass circuit, seems to be a favorable strategy to decrease postoperative morbidity after cardiac surgery in neonates and infants.

重炭酸リンゲル液を用いた血小板製剤の洗浄と保存

血小板製剤（PC）輸血時の非溶血性副作用発生頻度を低下させるためには，血漿の大部分を洗浄保存液に置換した洗浄血小板（WPC）が有効である．現在，日本では承認された洗浄保存液が無いため，市販の酢酸リンゲル液，重炭酸ナトリウム，硫酸マグネシウムなどの混液が使用されている．近年，アルカリ化剤として重炭酸塩が用いられた重炭酸リンゲル液（BRS）が開発された．本研究では，BRSが洗浄保存液として使用できるかどうか検討した． BRS 500mlにACD-A液25mlを添加し，その混液を除菌フィルターで処理して洗浄保存液（BRS-A）を調製した．BRS-Aで調製したWPC（血漿残存率5％未満）を7日間保存し，その機能を非洗浄PC（血漿浮遊）と比較した． 7日間保存中，洗浄血小板のpH，低浸透圧性ショック回復率，グルコース消費割合，乳酸産生割合，スワーリング，CD62P・CD42b発現率は非洗浄PCと同等かそれ以上に優れていた． 国内で認可されている2つの輸液を混合することにより，血小板機能を良好に維持する洗浄保存液を調製できた．今回の結果から，BRS-AはPCの洗浄保存液として有用であることが示された．

Comparative in vitro evaluation of apheresis platelets stored with 100% plasma versus bicarbonated Ringer's solution with less than 5% plasma

The major strategy for reducing the frequency of adverse reactions to platelet (PLT) transfusions is PLT washing with PLT additive solutions (PASs). In Japan, a mixture of medical infusion solutions such as acetate Ringer's solution, sodium bicarbonate, magnesium sulfate, and ACD-A is currently used as a PAS because none of the common types of PASs are officially permitted for clinical use. Recently, a bicarbonated Ringer's solution (BRS) was developed using bicarbonate as an alkaline agent. The aim of this study was to evaluate whether a BRS can effectively be utilized as a PAS for clinical use. The washing and storage solution was prepared by adding 25 mL ACD-A to 500 mL of BRS (BRS-A), consisting of 95.2 mmol/L NaCl, 3.8 mmol/L KCl, 0.9 mmol/L MgCl2 ,1.4 mmol/L CaCl2 , 26.6 mmol/L NaHCO3 , 5.8 mmol/L glucose, 4.2 mmol/L trisodium citrate, and 1.8 mmol/L citric acid. The in vitro properties of apheresis PLTs suspended in BRS-A with low concentration of plasma (<5%) were compared with those suspended in 100% plasma during 7-day storage. The in vitro properties of pH, hypotonic shock response, glucose consumption rate, lactate production rate, swirling, CD62P, and CD42b expression in PLTs suspended in BRS-A were comparable or superior to those suspended in 100% plasma during 7-day storage. BRS-A, prepared by mixing the only two solutions permitted for clinical use in Japan, has a positive capability to maintain PLT function. These results indicate that PLT washing and storage with BRS-A is feasible.

A comparison of Ringer's lactate and acetate solutions and resuscitative effects on splanchnic dysoxia in patients with extensive burns

A comparison of Ringer's lactate and acetate solutions and resuscitative effects on splanchnic dysoxia in patients with extensive burns

Cyclic Deformation of Newly Developed Magnesium Cast Alloys in Corrosive Environment

The moderate corrosion rate exhibits by Mg-RE alloys make it candidate material for biodegradable implant. Owing to the operating environment, implants are subjected to stochastic cyclic load and chemical condition. The alloys response to the subjected condition determines its degree of applicability. This work studies the cyclic deformation of newly developed Mg10GdxNd alloys both in air and under corrosive environment. The corrosion fatigue test was carried out in Ringer-Acetate solution and was evaluated using mechanical hysteresis and pH-value measurements. The microstructural changes in correlation to the deformation parameters and fracture surfaces were characterized using SEM. Results show that alloying Mg10Gd with Neodymium improved its fatigue live both in air and corrosive medium. Chilled casted Mg10Gd and Mg10GdxNd were found to undergo brittle fracture in both media. Loading in Ringer-Acetate was found to reduce the fatigue life of the investigated alloys due to the interaction of corrosion and fatigue processes on the microstructure of the alloys. EDX analysis suggests that the improved fatigue life observed on the Mg10GdxNd is connected to the new ternary Mg-Gd-Nd phase observed in the microstructure.

Experience of peripheral angioscopy in Scandinavia

Since we introduced angioscopy in autumn 1991 byin situ vein bypass operations we have used four different angioscopes with outer diameters of 2.2, 2.3, 2.8, and 2.9 mm. The 2.2 mm model was steerable, and collateral irrigation through a separate irrigation catheter was used. The other scopes had a built-in irrigation channel. Irrigation fluid was provided by a pressure cuff device placed around a liter of Ringer's acetate solution in plastic bag and inflated to between 200 and 300 mmHg. Recently we have used a roller pump that provides adjustment of the flow rate with a constant pressure of 200 mmHg. A Mills valve cutter was tested in the initial phase, but later the Insitucath proved more suitable. Valve disruption has been safe and confident. In addition, the angioscopy has been used as an adjuvant method in carotid endartectomies, thromboembolectomies, aortobifemoral reconstructions, iliacofemoral endarterectomies, in vascular access surgery, and percutaneous stent application. The visualization has been excellent or good and there have not been any significant complications due to the angioscopes. The use of angioscopy is well established in our arterial procedures and in the near future it will be introduced in venous surgery. The need for further studies concerning the significance of intraluminal findings is obvious.

Anesthesia for Bariatric Surgery

Bariatric surgery has a lot of problems in anesthesia. We retrospectively compared anesthesia for bariatric surgery in yellow race with that in normal weight patients. Twenty patients who received bariatric surgery and 20 normal body weight patients who received abdominal surgery in Japan were enrolled. Induction condition, depth of epidural space, dose of anesthetics, duration of the effects of muscle relaxants, ventilation, and fluid management in bariatric surgery were analyzed and compared with those in normal body weight patients. An epidural catheterization was successful under ultrasound guide in the bariatric group. The depth epidural space was significantly larger in the bariatric group. Cormack and Lehane classification and the number of intubation attempt were not different between the two groups, while one bariatric case was once awakened to intubate blindly. Pressure-controlled ventilation was used in the bariatric group. Four bariatric patients were continuously ventilated after surgery. The doses of anesthetics and fluid infusion rate were not different between the two groups when calculated by ideal body weight in the bariatric group. The duration of the effects of rocuronium and pancuronium were shorter in the bariatric group. For anesthesia of yellow race patients undergoing bariatric surgery, intravenous anesthetics and acetate Ringer's solution with 1% glucose could be administered per ideal body weight, the effects of muscle relaxants lasted shorter, pressure-controlled ventilation could keep oxygenation with adequate carbon dioxide, and ultrasound assist was useful in epidural catheterization in the bariatric patients.

Hydration Status After Overnight Fasting as Measured by Urine Osmolality Does Not Alter the Magnitude of Hypotension During General Anesthesia in Low Risk Patients

The increased distribution of crystalloid solution into the interstitial space may decrease the effectiveness of intravascular volume loading in patients. We investigated whether preoperative hydration status after overnight fasting affects interstitial fluid redistribution and thus the magnitude of hypotension during general anesthesia. Sixty ASA physical status I/II patients undergoing tympanoplasty fasted from midnight. Anesthesia was induced by fentanyl and propofol and maintained with sevoflurane and remifentanil. Coinciding with the induction of anesthesia, 15 mL/kg acetated Ringer solution was infused IV over 60 minutes followed by 1 mL/kg acetated Ringer solution over the next 30 minutes. Urine osmolalities after induction of anesthesia and during the study period (pre-U(osm), post-U(osm)) and percent decreases of whole-body bioelectrical resistance for extracellular fluid relative to baseline at the end of the study period (ΔR(e)) were measured. Patients with a pre-U(osm) < the 25th percentile or with a pre-U(osm) > the 75th percentile of pre-U(osm) were categorized in the hydrated or the dehydrated group, respectively. A range of variables, including mean arterial blood pressure during the 30- to 90-minute period relative to baseline, and ΔR(e), were compared between the groups. The dehydrated group (pre-U(osm) >759.5 mOsm/kg, n = 15) had a lower age (44 vs 52 years, P = 0.049) and had a higher post-U(osm) (181 vs 55 mOsm/kg, P = 0.001) compared with the hydrated group (pre-U(osm) <378.5 mOsm/kg, n = 15). Mean arterial blood pressure during the 30- to 90-minute period relative to baseline (0.67 vs 0.67, P = 0.85) with 95% confidence interval for the difference of means (-0.070 to 0.084) and ΔR(e) (5.6% vs 6.0%, P = 0.58) with 95% confidence interval for the difference of means (-1.85% to 1.06%) were similar for the hydrated and dehydrated groups. Preoperative dehydration after overnight fasting as measured by urine osmolality did not alter the magnitude of hypotension during general anesthesia. This finding suggests that intravascular volume loading with crystalloid solution to prevent hypotension during general anesthesia is an unfounded practice for low risk patients after overnight fasting.

Intravenous Lipid Emulsion Sequesters Amiodarone in Plasma and Eliminates Its Hypotensive Action in Pigs

Our objective is to investigate to what extent amiodarone is sequestered by intravenously administered lipid emulsion in plasma of pigs and whether the lipid emulsion inhibits amiodarone-induced hypotension. Twenty anesthetized pigs received randomly 1.5 mL/kg bolus injection of olive/soybean oil-based 20% lipid emulsion (lipid group, n=10) or Ringer's acetate solution (control group, n=10) in 1 minute, followed by a continuous infusion of either solution for 30 minutes at 0.25 mL/kg per minute. Simultaneously with these continuous infusions, amiodarone hydrochloride was infused for 20 minutes at 1 mg/kg per minute in both groups. Plasma amiodarone concentration and mean arterial blood pressure were evaluated at predetermined intervals. Plasma amiodarone concentration in the lipid group increased more steeply during the amiodarone infusion than in the control group, at 20 minutes being a median 96.8 mg/L (interquartile range [IQR] 85.4, 102.0 mg/L) in the lipid group and median 21.5 mg/L (IQR 18.9, 22.3 mg/L) in the control group (difference 75.3 mg/L; 95% confidence interval [CI] 65.3 to 85.3 mg/L). After the separation of lipids from plasma by differential centrifugation, less amiodarone was contained in the lipid-poor aqueous fraction. At 20 minutes, the median was 13.3 mg/L (IQR 12.0, 13.7 mg/L), and the difference compared with the total plasma amiodarone concentration was -83.6 mg/L (95% CI -93.3 to -73.8 mg/L). In the lipid group, mean arterial blood pressure was not altered during the continuous amiodarone infusion. In the control group, mean arterial blood pressure decreased from baseline at 11 minutes, and the median was 52 mm Hg (IQR 51, 80 mm Hg) and the difference from baseline was 26 mm Hg (95% CI 9 to 43 mm Hg). Mean arterial blood pressure at 21 minutes also remained below the baseline, and the median was 57 mm Hg (IQR 50, 68 mm Hg) and the difference from baseline was 21 mm Hg (95% CI 9 to 33 mm Hg). Amiodarone was sequestered to a great extent by the intravenously administered lipids in plasma, which completely prevented the decrease in arterial blood pressure caused by amiodarone infusion. Further studies are needed to evaluate the clinical usefulness of intravenous lipid emulsion as an antidote in amiodarone overdoses.

A comparison of Ringer's lactate and acetate solutions and resuscitative effects on splanchnic dysoxia in patients with extensive burns

We compared the effects of Ringer's lactate (RL) and acetate (RA) solutions on parameters of splanchnic dysoxia such as PgCO 2 (PCO 2 of gastric mucosa) and pH i (pH of gastric mucosa) using a gastric tonometer, in addition to blood markers such as the serum arterial level of lactate, base excess, ketone body ratio, and antithrombin during the first 72 h of the resuscitation period in patients with burns covering 30% or more of their body surface. A prospective study was conducted in the university tertiary referral centers. There were no significant differences in the average age, TBSA (total burn surface area), and resuscitative fluid volume during the first and second 24 h between the two groups. In the RA group, PCO 2 gap values calculated employing the formula: PgCO 2 − PaCO 2 (arterial PCO 2), and pH gap calculated by: pH a (arterial pH) − pH i, improved to the normal ranges at 24 h postburn, which was significantly faster than in the RL group. On the other hand, there were no significant differences in blood parameters between the two groups over the course. These results suggest that fluid resuscitation with RA may more rapidly ameliorate splanchnic dysoxia, as evidenced by gastric tonometry, compared to that with RL.

Infusions of albumin increase free fraction of naproxen in healthy volunteers: a randomized crossover study

In vitro and in vivo studies have indicated that stabilizers present in pharmaceutical-grade albumin influence the albumin-binding capacity for highly protein-bound drugs. However, the half-life of the stabilizers and the quantitative effect have been difficult to determine. A randomized crossover study including six healthy volunteers was performed. The study subjects received 750 mg of oral naproxen 2 h before the study. They were randomized to receive either 100 ml of 20% albumin or 100 ml of Ringer's acetate solution intravenously. Frequent blood samples were obtained. The experiment was repeated 4 weeks later with the alternate solution. The serum samples were analysed to determine the concentrations of albumin, N-acetyl-DL-tryptophan, caprylate, and naproxen. The free fraction of naproxen increased significantly after the infusion of albumin (P<0.05). The increase was concurrent with the appearance of N-acetyl-DL-tryptophan and caprylate in serum. The free fraction of naproxen declined rapidly after the albumin infusion was completed. N-acetyl-DL-tryptophan had a half-life of approximately 30 min. The half-life of caprylate was <15 min. A transfusion of albumin results in an increase in the free fraction of naproxen. The transient increase in free-fraction naproxen decreased together with the detectable levels of the stabilizers N-acetyl-DL-tryptophan and caprylate. N-acetyl-DL-tryptophan and caprylate have a short half-life in serum.

Effects of balanced and unbalanced colloid and crystalloid solutions on renal oxygenation in a rat model of hemorrhagic shock and resuscitation

Hydroxyethyl starch (HES, 130 kD) dissolved either in saline (Voluven®) or in a balanced Ringer's acetate solution (PlasmaVolume Redibag®, PVR) and Ringer's acetate (RA) and 0.9% NaCl (NaCl) were investigated as regards their efficacy in restoring renal oxygenation in a rat model of hemorrhagic shock and resuscitation.

Is high diuresis an important prerequisite for successful SWL-disintegration of ureteral stones?

A randomised comparison was made between high and normal diuresis during the primary session of extracorporeal shock wave lithotripsy (SWL) for removal of ureteral stones. High diuresis was accomplished by pressure infusion of approximately 1 L of Ringer acetate solution together with 20 mg of furosemide during the 30-40 min treatment session (Group D). These patients also had a bladder catheter. Patients in Group 0 had a normal diuresis and no bladder catheter. The mean (SD) number of treatment sessions for the 65 patients in Group D were 1.26 (0.51) and for the 60 patients from Group 0 1.35 (0.84) [p > 0.10]. 51 (78%) and 46 (77%) patients in Group D and Group 0, respectively, required only one SWL session. Stones were located in the proximal, mid and distal ureter in 22, 9, and 29 of the patients in Group D and in 22, 5, and 38 in Group 0. No difference in treatment outcome was observed with regard to stone localisation. The stone treatment index (STI(GR)) calculated for Group D and Group 0 were 4.77 and 4.70, respectively. In conclusion there was no obvious advantage of using a forced diuresis during the primary SWL-session for treating patients with ureteral stones. Although a high diuresis and bladder catheter might be beneficial in certain complicated cases, in most situations it seems appropriate to omit this step.

Effect of administration of pre-warmed intravenous fluids on the frequency of hypothermia following spinal anesthesia for Cesarean delivery

Study Objective To determine whether administration of pre-warmed colloid followed by pre-warmed crystalloid solution prevents the development of hypothermia in patients undergoing Cesarean delivery. Design Randomized, double-blind, placebo-controlled study. Patients 30 parturients scheduled to undergo elective Cesarean delivery during spinal anesthesia. Interventions Patients assigned to the warmed fluid group (n=15) received pre-warmed colloid with average molecular weight of 70,000 daltons and substitution ratio of 0.55, followed by pre-warmed crystalloid (kept in warmed storage maintained at 41 °C) during surgery. Patients assigned to the unwarmed fluid group (n=15) received non-warmed infusion. All patients received 400 mL before spinal anesthesia followed by another 300 mL before delivery of the newborn. After completion of a 1,000 mL infusion of colloid fluid, acetate Ringer's solution was infused. Measurements Core temperature measured at the tympanic membrane, and forearm and fingertip skin temperatures were recorded just after arrival at the operating room (baseline), after administration of spinal anesthesia (spinal ), at incision (incision), at delivery of the newborn (delivery), and at 15, 30, and 45 minutes after delivery. Rectal temperature of the baby, Apgar scores at one and 5 minutes after delivery, and umbilical artery pH were evaluated. Main Results Core temperature was significantly higher in the warmed fluid group from the time of delivery to 45 minutes after delivery. Apgar scores at one minute after delivery and umbilical arterial pH were significantly higher in the warmed fluid group. Conclusion Administration of pre-warmed intravenous colloid followed by crystalloids maintained core temperature during Cesarean delivery and induced higher Apgar scores and umbilical arterial pH.

Intrakranieller Druck und hypotone Infusionslösungen

The physiological osmolality of plasma is 288+/-5 mosmol/kgH2O when measured by freezing-point depression. The theoretical osmolarity (290 mosmol/l) calculated from composition, osmotic coefficient (0.93) and water content (0.94) is practically identical. Saline (0.9% NaCl) has an osmolarity of 308 mosmol/l and an osmolality of 286 mosmol/kgH2O (water content ca. 1.0). The osmolality in vivo is more important than that measured in vitro. A 5% dextrose solution in water (D5W) is isotonic in vitro, but the in vivo effect is that of pure water because the glucose is rapidly metabolized. Every infusion fluid should be isotonic (290+/-10 mosmol/kgH2O). Hypotonic solutions must move water from the extracellular space to the intracellular space. Typical examples are Ringer's lactate and acetate solutions (256 instead of 290 mosmol/kgH2O). The brain (central nervous system, CNS) is the critical organ: The rigidly shaped skull contains three incompressible compartments, only blood and cerebrospinal fluid (CSF) can be partially, but limitedly shifted outside the skull. The consequence of a volume load is an increasing intracranial pressure (ICP). A decrease in plasma osmolality by only 3% produces an increase in ICP of about 15 mmHg. Therefore, infusion of larger volumes of hypotonic solutions should be avoided at all costs.

Comparison of the Alkalizing Effects of Bicarbonate Precursors in Calves with Experimentally Induced Metabolic Acidosis

The aims of this study were to confirm whether commercial acetated Ringer's solution, which contains 28 mM of sodium acetate, is superior to commercial lactated Ringer's solution in alkalizing effects in calves with experimentally induced metabolic acidosis. Twenty calves with experimentally induced mild acidosis were intravenously administered isotonic saline, DL-lactated, L-lactated or acetated Ringer's solution at a dose of 80 ml/kg body weight (BW). The acetated Ringer's solution induced a significantly greater increase in venous HCO(3)(-) and base excess concentrations than the other fluids during the early phases of extracellular fluid replacement in mild metabolic acidosis. Therefore, the alkalizing effect of commercial acetated Ringer's solution is superior to commercial DL- and L-lactated Ringer's solution in treatment of mild metabolic acidosis in calves.

A case of severe postoperative airway edema induced by hyperflexion of the neck

To the editor: We encountered a patient in whom severe air- way edema occurred after a relatively short duration of gen- eral anesthesia, with post-surgical mechanical ventilation being necessary. Reduction of local venous circulation in the surgical position (hyperfl exion of the neck) may have been the main cause of the edema. The patient was an 83-year-old woman (150 cm; 62 kg; body mass index (BMI), 27.6) scheduled to undergo excision of a right parotid tumor. The patient had a previous medical his- tory of hypertension, treated with a calcium channel blocker (nifedipine). She was also being treated with nitroglycerin for negative T wave on ECG, but she had no subjective symp- toms, such as chest pain, nor were there any symptoms of heart failure or a cold, such as pharyngeal pain or cough. No anesthetic premedication was administered. Anesthesia was induced with 100 mg propofol, 100 μg fentanyl, and 6 mg vecuronium, and maintained with oxygen, nitrous oxide, and sevofl urane (0.5%-2%). After oropharyngeal intubation with a tracheal tube (6.5 mm in diameter), 6 ml of air was infused into the cuff until air leakage from the tube disappeared. No abnormalities, such as fl are or swelling, were noted with laryngoscopy. The tracheal tube was easily inserted. After a central venous catheter was inserted into the femo- ral vein, nitroglycerin was continuously administered at 0.5 μg·kg −1 ·min −1 , and central venous pressure was measured. The operator placed the patient's neck in a left fl exion position to turn the affected side upward; the left side of the operation table was inclined to about 10°; and surgery was initiated. Surgery was performed without any problem. The tumor was localized in the parotid gland, without tracheal invasion. The operation time was 157 min, the duration of anesthesia was 200 min, the infused volume of Ringer's acetate solution was 1100 ml, the blood loss was 50 ml, urinary volume was 400 ml, and intraoperative central venous pressure was 3- 5 mmHg. When the patient's head was returned to the median position after the completion of surgery, edema was noted in the eyelid and conjunctiva on the unaffected side. No edema was noted macroscopically in the neck. No leakage was con- Fig. 1. Image of bronchofi berscopy, performed through the tracheal tube, just after the surgery. Edema was present in the entire circumference of the trachea, and the membranous re- gion bulged homogeneously