Two-stage laparoscopic transversus abdominis plane block as an equivalent alternative to thoracic epidural anaesthesia in bowel resection-an explorative cohort study.

PURPOSE: We evaluated the effect of the two-stage laparoscopic transversus abdominis plane block (TS-L-TAPB) in comparison to thoracic epidural anaesthesia (TEA) and a one-stage L-TAPB (OS-L-TAPB) in patients who underwent elective laparoscopic bowel resection. METHODS: We compared a TS-L-TAPB (266 mg bupivacaine), which was performed bilaterally at the beginning and end of surgery, with two retrospective cohorts. These were patients who had undergone a TEA (ropivacaine/sufentanil) or an OS-L-TAPB (200 mg ropivacaine) at the beginning of surgery. Oral and i.v. opiate requirements were documented over the first 3 postoperative days (POD). RESULTS: Patients were divided into three groups TEA (n = 23), OS-L-TAPB (n = 75), and TS-L-TAPB (n = 49). By the evening of the third POD, patients with a TEA had a higher cumulative opiate requirement with a median of 45.625 mg [0; 202.5] than patients in the OS-L-TAPB group at 10 mg [0; 245.625] and the TS-L-TAPB group at 5.625 mg [0; 215.625] (p = 0.1438). One hour after arrival in the recovery room, significantly more patients in the TEA group (100%) did not need oral and i.v. opioids than in the TS-L-TAPB (78%) and OS-L-TAPB groups (68%) (p = 0.0067).This was without clinical relevance however as the median in all groups was 0 mg. On the third POD, patients in the TEA group had a significantly higher median oral and i.v. opioid dose at 40 mg [0; 80] than the TS-L-TAPB and OS-L-TAPB groups, both at 0 mg [0; 80] (p = 0.0009). CONCLUSION: The TS-L-TAP showed statistically significant and clinically meaningful benefits over TEA and OS-L-TAP in reducing postoperative opiate requirements.

Mutation frequency of NS5A in patients vertically infected with HCV genotype 1 predicts sustained virological response to peginterferon alfa-2b and ribavirin combination therapy.

Viral genome analyses performed in adult HCV-patients yielded very inconsistent results and are not transferable to children who are often infected vertically during a state of high immune tolerance. We analysed the mutational frequency in the PKR-binding domain (PKR-BD) of NS5A and PePHD of E2 protein pre- and post-treatment with peginterferon-alfa-2b and ribavirin in children chronically infected with HCV genotype 1. Amino acid sequences of NS5A (2 209-2 274) and E2 (618-681) were determined in serum samples using standard PCR procedures. Concerning the PKR-BD a significant higher number of mutations was observed in vertically compared to horizontally infected patients (2.14 vs 1.24, P-value = 0.03). This difference was exclusively based on the increased number of mutations in responders vs non-responders in vertically infected patients (2.95 vs 1.33; P-value = 0.02). While all patients with at least four mutations (n = 3) did respond to therapy, no other predictive parameters could be identified. In the PePHD no differences could be observed between either of these groups. These findings support the idea that viral properties, mode and therewith time of infection in terms of immune tolerance are equally important factors for predicting SVR in children. However given the low number of cases further studies are required to confirm this hypothesis.

[Exact measurement of the volume effect of 6% hydoxyethyl starch 130/0.4 (Voluven) during acute preoperative normovolemic hemodilution]. / Exakte Messung des Volumeneffektes von 6%iger Hydroxyethylstärke 130/0.4 (Voluven) während präoperativer akuter normovolämer Hämodilution.

BACKGROUND: What is the effect of preoperative acute normovolemic hemodilution (ANH) with 6% hydroxyethyl starch (HES) 130/0.4 (Voluven) on blood volume? METHODS: In 10 patients undergoing radical hysterectomy, ANH was performed to a hematocrit of 21% using 6% HES 130/0.4 (Voluven) whereby a replacement of blood with 115% of colloid was planned. Plasma volume (indocyanine green dilution technique) and hematocrit were determined before, 30 and 60 min after ANH. Red cell volume (labelling erythrocytes with fluorescein) was determined before and 30 min after ANH. RESULTS: After removal of 1,431+/-388 ml of blood and simultaneous replacement with 1,686+/-437 ml of colloid, blood volumes were 218+/-174 ml higher than before (at 105+/-4%). The volume effect was 98+/-12%, 30 min after ANH. Even 60 min after ANH, mean blood volumes were with 4,228+/-986 ml slightly higher than before ANH (102+/-5%). The hematocrit decreased disproportionally in relation to the residual intravascular volume. Consequently, estimating the volume effect from the changes in hematocrit led to an overestimation (about +30%). CONCLUSION: Double label measurements of blood volume demonstrated that the volume effect of 6% HES 130/0.4 (Voluven) is about 100% in the course of ANH. The reason for the disproportionally large decrease in hematocrits could be the mobilization of a fraction of the plasma volume which was retained within the endothelial glycocalyx.

Changes in blood volume and hematocrit during acute preoperative volume loading with 5% albumin or 6% hetastarch solutions in patients before radical hysterectomy.

BACKGROUND: The impact of acute preoperative volume loading with colloids on blood volume has not been investigated sufficiently. METHODS: Before surgery, in 20 patients undergoing major gynecologic procedures, volume loading was performed during anesthesia by infusing approximately 20 ml/kg of colloid at a rate of 90 ml/min (group I: 5% albumin solution; group II: 6% hetastarch solution; n = 10 each). Plasma volume (indocyanine green dilution technique), erythrocyte volume (labeling erythrocytes with fluorescein), hematocrit, total protein, and hetastarch plasma concentrations (group II) were measured before and 30 min after the end of infusion. RESULTS: More than 1,350 ml of colloid (approximately 50% of the baseline plasma volume) were infused within 15 min. Thirty minutes after the infusion had been completed, blood volume was only 524 +/- 328 ml (group I) and 603 +/- 314 ml (group II) higher than before volume loading. The large vessel hematocrit (measured by centrifugation) dropped more than the whole body hematocrit, which was derived from double-label measurements of blood volume. CONCLUSIONS: The double-label measurements of blood volume performed showed that 30 min after the infusion of approximately 20 ml/kg of 5% albumin or 6% hetastarch solution (within 15 min), only mean 38 +/- 21% and 43 +/- 26%, respectively, of the volume applied remained in the intravascular space. Different, i.e., earlier or later, measuring points, different infusion volumes, infusion rates, plasma substitutes, or possibly different tracers for plasma volume measurement might lead to different results concerning the kinetics of fluid or colloid extravasation.

[The measurement of blood volume--state-of-the-art]. / Die Messung des Blutvolumens--aktueller Stand.

The term blood volume (BV) measurement can be understood as the exact volumetric definition of both components of blood, the red cell volume (RCV) and the plasma volume (PV) using tracer dilution methods. The tracer used to measure the RCV must be bound to the erythrocytes and for the PV to plasma proteins, in order to label the distribution space of each carrier (i.e. erythrocytes and albumin molecules). To differentiate this there are indirect methods to estimate the BV, such as measurement of the diastolic pressure or transoesophageal echocardiography, which will not be discussed here. Alterations in the RCV and PV cannot be routinely measured, or at most only roughly estimated by means of the haematocrit (Hc) or haemoglobin (Hb) concentration which can lead to serious errors when large changes have occurred. At present measurements of the RCV and PV are not carried out in routine clinical practice. The introduction of nonradioactive tracers with a faster elimination now renders possible a relatively exact measurement of both volumes under certain clinical situations, albeit with a high technical outlay. The RCV is measured using the tracer sodium fluorescein (SoF) and the PV with the dye indocyanine green (ICG). The RCV measurement seems to be suitable for certain clinical situations, such as characterization of the preoperative condition of a patient or quantification of surgical blood loss after an operation, because it is less invasive and has a high precision. However, the results of the RCV measurement can only be delivered after 1 h which makes it more suitable for clinically stable situations. In contrast the PV estimation is based on the measurement of the ICG concentration in the arterial bloodstream after a bolus injection of the dye in the central veins and is used more in intensive care because of the invasivity. The results can be obtained 5 min after injection of the dye and therefore even rapid changes in the PV can be monitored.

[Changes in blood volume during acute normovolemic hemodilution with 5% albumin or 6% hydroxyethylstarch and intraoperative retransfusion]. / Veränderungen des Blutvolumens während akuter normovolämer Hämodilution mit 5% Albumin oder 6% Hydroxyäthylstärke und intraoperativer Retransfusion.

QUESTION: What is the impact of acute preoperative normovolemic hemodilution (ANH) on blood volume, intravascular colloid, and loss of red cells in the perioperative period? METHODS: In 20 patients undergoing radical hysterectomy, preoperative ANH was performed to a hematocrit of 22% using 5% albumin (albumin group; n = 10) or 6% hydroxyethylstarch solution (HES group; n = 10). Intraoperative retransfusion of ANH blood was started at a hematocrit of 18%. Plasma volume (indocyanine green-dilution technique), hematocrit, and plasma protein concentration were measured before and after ANH, before retransfusion, and postoperatively. Red cell volume (labelling erythrocytes with fluorescein) was determined before and after ANH and postoperatively. In the HES group hydroxyethylstarch concentrations were measured in plasma and urine. RESULTS: After removal of about 1,500 ml of blood and replacement with 15% more colloid solution, the blood volume was maintained in both groups after ANH. After a mean blood loss of about 1,800 ml, an average of 150 ml of red cells were saved due to ANH in both groups. CONCLUSIONS: Double label measurements of blood volume demonstrated that with the colloids used a surplus of 15% of colloid infusion in relation to blood removal was necessary to generate isovolemia after ANH.

[Acute "normovolemic" hemodilution with 3.5% polygel (Haemaccel) for patients in the Wertheim-Meigs-operation. Blood loss of 87% blood volume without perioperative blood transfusion]. / Akute "normovoläme" Hämodilution mit 3,5% Polygelin (Haemaccel) bei einer Patientin vor Wertheim-Meigs-Operation. Blutverlust von 87% des Blutvolumens ohne perioperative Fremdbluttransfusion.

QUESTION: Is polygeline (Haemaccel) a suitable colloid to perform preoperative acute normovolemic hemodilution (ANH) and to replace a large intraoperative blood loss? METHODS: In a sixty-eight-year-old patient undergoing radical hysterectomy preoperative ANH was performed to a hematocrit of 23% using 3.5% polygeline (Haemaccel). Intraoperative retransfusion of ANH blood was started at a hematocrit of 13%. Plasma volume (indocyanine green-dilution technique) and hematocrit were measured before and after ANH, 3 times intraoperatively (once before retransfusion) and postoperatively. Red cell volume (by labelling erythrocytes with fluorescein) was determined before and after ANH, before retransfusion, and postoperatively. RESULTS: After removal of 1,940 ml of blood and replacement with 15% more of colloid, blood volume decreased by 760 ml. After a mean blood loss of 4,600 ml, 290 ml and 260 ml of red cells were saved due to ANH and use of a cell saver, respectively. CONCLUSIONS: The exact double label measurements of blood volume demonstrated that polygeline, which has a volume effect of only 50%, cannot be considered to be a suitable colloidal substitute during ANH.

Acid-base changes caused by 5% albumin versus 6% hydroxyethyl starch solution in patients undergoing acute normovolemic hemodilution: a randomized prospective study.

BACKGROUND: Preoperative acute normovolemic hemodilution (ANH) is an excellent model for evaluating the effects of different colloid solutions that are free of bicarbonate but have large chloride concentrations on acid-base equilibrium. METHODS: In 20 patients undergoing gynecologic surgery, ANH to a hematocrit of 22% was performed. Two groups of 10 patients each were randomly assigned to receive either 5% albumin or 6% hydroxyethyl starch solutions containing chloride concentrations of 150 and 154 mm, respectively, during ANH. Blood volume (double label measurement of plasma and red cell volumes), pH, Paco2, and serum concentrations of sodium, potassium, chloride, lactate, ionized calcium, phosphate, albumin, and total protein were measured before and 20 min after completion of ANH. Strong ion difference was calculated as serum sodium plus serum potassium minus serum chloride minus serum lactate. The amount of weak plasma acid was calculated using a computer program. RESULTS: After ANH, blood volume was well maintained in both groups. ANH caused slight metabolic acidosis with hyperchloremia and a concomitant decrease in strong ion difference. Plasma albumin concentration decreased after hemodilution with 6% hydroxyethyl starch solution and increased after hemodilution with 5% albumin solution. Despite a three-times larger decrease in strong ion difference after ANH with 6% hydroxyethyl starch solution, the decrease in pH was nearly the same in both groups. CONCLUSIONS: ANH with 5% albumin or 6% hydroxyethyl starch solutions led to metabolic acidosis. A dilution of extracellular bicarbonate or changes in strong ion difference and albumin concentration offer explanations for this type of acidosis.

Changes in intravascular volume during acute normovolemic hemodilution and intraoperative retransfusion in patients with radical hysterectomy.

BACKGROUND: Changes in blood volume during acute normovolemic hemodilution (ANH) and their consequences for the perioperative period have not been investigated sufficiently. METHODS: In 15 patients undergoing radical hysterectomy, preoperative ANH to a hematocrit of 24% was performed using 5% albumin solution. Intraoperatively, saline 0.9% solution was used for volume substitution, and intraoperative retransfusion was started at a hematocrit of 20%. Plasma volume (indocyanine green dilution technique), hematocrit, and plasma protein concentration were measured before and after ANH, before retransfusion, and postoperatively. Red cell volume (labeling erythrocytes with fluorescein) was determined before and after ANH and postoperatively. RESULTS: Mean normal plasma volumes (1,514 +/- 143 ml/m2) and reduced red cell volumes (707 +/- 79 ml/m2) were measured preoperatively. Blood (1,150 +/- 196 ml) was removed and replaced with 1,333 +/- 204 ml of colloid. Blood volume before and after ANH was equal and amounted to 3,740 ml. Intraoperatively, plasma volume did not increase until retransfusion despite infusing 3,389 +/- 1,021 ml of crystalloid (corrected for urine output) to compensate for an estimated surgical blood loss of 727 +/- 726 mi. Postoperatively, after retransfusion of all autologous blood, blood volume was 255 +/- 424 ml higher than preoperatively before ANH. Despite mean calculated blood loss of 1,256 +/- 892 ml, only one patient received allogeneic blood. CONCLUSIONS: During ANH, normovolemia was exactly maintained. After surgical blood loss of 1,256 +/- 892 ml, crystalloid and colloid supplies of 5,752 +/- 1,462 ml and 1,667 +/- 548 ml, respectively, and complete intraoperative retransfusions of autologous blood in every patient, mean blood volume was 250 ml higher than preoperatively before ANH.

First clinical implications of perioperative red cell volume measurement with a nonradioactive marker (sodium fluorescein).

UNLABELLED: We measured red cell volume (RCV) with the nonradioactive marker sodium fluorescein (SoF) in 30 patients undergoing gynecological operations. Sixteen patients underwent preoperative isovolemic hemodilution (PIHD). RCV measurements were performed before and after PIHD and at the end of the operation. All RCVs were related to corresponding hematocrit (hct) levels. We report a simplified method for its clinical application by reducing the number of blood samples required. To validate our method, we compared RCV within the PIHD bags (bag RCV) with the difference of the patients' RCV before and after PIHD. Bag RCV obtained during PIHD (mean 399+/-81 mL) was measured with a precision of 4.2% by using SoF. There was a significant difference (mean 286+/-401 mL; P < 0.05) between intraoperatively estimated and measured blood loss. The blood loss tended to be underestimated and, in some cases, was underestimated or overestimated substantially. Preoperative and postoperative hct values only offered an imprecise estimation of the patients' RCV. We conclude that RCV measurement using SoF is a precise method for monitoring changes in RCV during PIHD and surgical operation. IMPLICATIONS: We measured red cell volume changes of 30 patients with the nonradioactive marker sodium fluorescein before and after hemodilution and postoperatively with a high precision. We frequently found large differences between intraoperatively estimated and measured blood loss. Preoperative hematocrit values offered an imprecise estimation of the patients' red cell volume.

Operon fusions in the nitrate reductase operon and study of the control gene nir R in Escherichia coli.

Strains carrying operon fusions between the promotor of the chl I gene and the lac structural genes were constructed. From these strains in which the expression of the lac genes is under the control of both nitrate and oxygen, spontaneous regulatory mutants were selected: (i) mutants which synthesize beta-galactosidase constitutively in anaerobiosis; (ii) mutants in which beta-galactosidase synthesis is no longer repressed by oxygen. Introduction of the nir R mutated allele into strains carrying these fusions resulted in the total loss of beta-galactosidase synthesis, confirming that nir R is a regulatory gene controlling the expression of the biosynthesis of the nitrate reductase.

Nitrate reductase and cytochrome bnitrate reductase structural genes as parts of the nitrate reductase operon.

The existence of a nitrate-reductase operon in the tryptophane region was deduced from the effects of prophage insertion in each of chlI and chlC genes and from transposition of the Mu-mediated host DNA fragments of F-prime. This operon appears to be polarized from chlC to chlI and the gene order in the region is trp -- chlI -- chlC -- purB.

A mutant defective in electron transfer to nitrate in Escherichia coli K12.

A mutant of Escherichia coli K12 is described which is unable to reduce nitrate with a variety of physiological electron donors but which retains nitrate reductase activity with the artificial electron donor benzyl viologen. It is suggested that the affected gene, chlI, located close to chlC, encodes the cytochrome bNR apoprotein.