Accuracy, Precision, and Trending Ability of Electrical Cardiometry Cardiac Index versus Continuous Pulmonary Artery Thermodilution Method: A Prospective, Observational Study.

INTRODUCTION: Evaluation of accuracy, precision, and trending ability of cardiac index (CI) measurements using the Aesculon™ bioimpedance electrical cardiometry (Aesc) compared to the continuous pulmonary artery thermodilution catheter (PAC) technique before, during, and after cardiac surgery. METHODS: A prospective observational study with fifty patients with ASA 3-4. At six time points (T), measurements of CI simultaneously by continuous cardiac output pulmonary thermodilution and thoracic bioimpedance and standard hemodynamics were performed. Analysis was performed using Bland-Altman, four-quadrant plot, and polar plot methodology. RESULTS: CI obtained with pulmonary artery thermodilution and thoracic bioimpedance ranged from 1.00 to 6.75 L min-1 and 0.93 to 7.25 L min-1, respectively. Bland-Altman analysis showed a bias between CIBIO and CIPAC of 0.52 liters min-1 m-2, with LOA of [-2.2; 1.1] liters min-1 m-2. Percentage error between the two techniques was above 30% at every time point. Polar plot methodology and 4-quadrant analysis showed poor trending ability. Skin incision had no effect on the results. CONCLUSION: CI obtained by continuous PAC and CI obtained by Aesculon bioimpedance are not interchangeable in cardiac surgical patients. No effects of skin incision were found. International clinical trial registration number is ISRCTN26732484.

Routine labour epidural analgesia versus labour analgesia on request: a randomised non-inferiority trial.

OBJECTIVE: To assess the effect on mode of delivery of the routine use of labour epidural analgesia (EA) compared with analgesia on request. DESIGN: Randomised non-inferiority trial. SETTING: One university and one non-university teaching hospital in The Netherlands. POPULATION: Women with a singleton pregnancy in cephalic presentation beyond 36 + 0 weeks' gestation. METHODS: Participants were randomly allocated to receive either routine EA or analgesia on request. Intention-to-treat (ITT) and per-protocol (PP) analyses were performed, with confidence intervals (CI) calculated for the differences in percentages or means. MAIN OUTCOME MEASURES: Rate of operative delivery (instrumental vaginal or caesarean), labour characteristics, and adverse labour and neonatal outcomes. RESULTS: A total of 488 women were randomly allocated to the routine EA (n = 233) or analgesia on request group (n = 255). In the routine EA group, 89.3% (208/233) received EA. According to ITT analysis, 34.8% (81/233) women in the routine EA group had an operative delivery, compared with 26.7% (68/255) in the analgesia on request group (difference 8.1%, 95% CI -0.1 to 16.3). The difference in rate of operative deliveries according to the PP analysis was statistically significant (difference 8.9%, 95% CI 0.4 to 17.4). Inferiority of EA could not be rejected, as in both analyses the upper bound of the confidence interval exceeded the pre-specified inferiority criterion of +10%. Women in the routine EA group had more adverse effects, including hypotension (difference 9.5%, 95% CI 4.2 to 14.9), and motor blockade (difference 6.8%, 95% CI 1.1 to 12.5). CONCLUSION: Non-inferiority of routine EA could not be demonstrated in this trial. Routine EA use is likely to lead to more operative deliveries and more maternal adverse effects. The results of our study do not justify routine use of EA.

Additive roles of platelets and fibrinogen in whole-blood fibrin clot formation upon dilution as assessed by thromboelastometry.

Blood dilution after transfusion fluids leads to diminished coagulant activity monitored by rotational thromboelastometry, assessing elastic fibrin clot formation, or by thrombin generation testing. We aimed to determine the contributions of blood cells (platelets, red blood cells) and plasma factors (fibrinogen, prothrombin complex concentrate) to fibrin clot formation under conditions of haemodilution in vitro or in vivo.Whole blood or plasma diluted in vitro was supplemented with platelets, red cells, fibrinogen or prothrombin complex concentrate (PCC). Thromboelastometry was measured in whole blood as well as plasma; thrombin generation was determined in parallel. Similar tests were performed with blood from 48 patients, obtained before and after massive fluid infusion during cardiothoracic surgery.Addition of platelets or fibrinogen, in additive and independent ways, reversed the impaired fibrin clot formation (thromboelastometry) in diluted whole blood. In contrast, supplementation of red blood cells or prothrombin complex concentrate was ineffective. Platelets and fibrinogen independently restored clot formation in diluted plasma, resulting in thromboelastometry curves approaching those in whole blood. In whole blood from patients undergoing dilution during surgery, elastic clot formation was determined by both the platelet count and the fibrinogen level. Thrombin generation in diluted (patient) plasma was not changed by fibrinogen, but improved markedly by prothrombin complex concentrate. In conclusion, in dilutional coagulopathy, platelets and fibrinogen, but not red blood cells or vitamin K-dependent coagulation factors, independently determine thromboelastometry parameters measured in whole blood and plasma. Clinical decisions for transfusion based on thromboelastometry should take into account the platelet concentration.

Perioperative dilutional coagulopathy treated with fresh frozen plasma and fibrinogen concentrate: a prospective randomized intervention trial.

BACKGROUND AND OBJECTIVES: Treatment of dilutional coagulopathy by transfusing fresh frozen plasma (FFP) remains sub-optimal. We hypothesized that partial replacement of transfused FFP by fibrinogen concentrate results in improved coagulant activity and haemostasis. This was tested in a controlled clinical intervention trial with patients experiencing massive bleeding during major surgery. METHODS: Patients undergoing major elective surgery were treated according to current protocols. When transfusion with FFP was required, patients were randomized as follows: group A received 4 units FFP and group B received 2 units FFP plus 2 g fibrinogen concentrate. Blood samples were taken before and after the intervention. Analysts were blinded to the treatment type. RESULTS: Group A (B) consisted of 21 (22) patients, in 16 (17) of whom bleeding stopped after intervention. Plasma fibrinogen increased significantly more in group B (0·57 g/l) than in group A (0·05 g/l). However, levels of prothrombin and factors VIII, IX and X increased more in group A than in group B. Rotational thromboelastometry (ROTEM) of whole blood and plasma revealed improved fibrin clot formation in group B but not in group A. Thrombin generation [calibrated automated thrombogram (CAT)] in plasma increased more in group A. Principal parameters determining whole-blood thromboelastometry were the fibrinogen level and platelet count. In vitro addition of fibrinogen and prothrombin complex concentrate to pre-intervention samples restored both ROTEM and CAT parameters. CONCLUSIONS: Partial replacement of transfused FFP by fibrinogen increases fibrin clot formation at the expense of less improved thrombin generation. Coagulation factors other than fibrinogen alone are required for full restoration of haemostasis.

Platelet concentrate transport in pneumatic tube systems--does it work?

Blood sample transport via pneumatic tube systems (PTS) reduces the turnaround time of laboratories, but it might influence analysis results. Its effect on platelet concentrates (PCs) is not known. Platelet function was investigated after single and multiple PTS transport in comparison with storage and irradiation. Optical and impedance aggregation, CD-62, and microparticles changed as a result of storage, but not due to transport. Irradiation lowered platelet function independently. Multiple transport impaired thrombin receptor-activating peptide-induced aggregation. This investigation demonstrates the feasibility of PTS transport. As platelet function depends on storage, it may be more important to transfuse fresh PCs.

Endotracheal intubation using videolaryngoscopy causes less cardiovascular response compared to classic direct laryngoscopy, in cardiac patients according a standard hospital protocol.

INTRODUCTION: Previous studies comparing Glidescope and classic direct laryngoscopy did not show an attenuation of CV responses to endotracheal intubation. In the present study, we hypothesize that indirect videolaryngoscopy can attenuate cardiovascular responses to endotracheal intubation. METHODS: In a randomized cross-over study, eighty adults (ASA PS II-III) were included. Both direct and indirect videolaryngoscopies were used in a random order, in the same patient. Cardiovascular responses to intubation were recorded as a relative change in rate pressure product (RPP = systolic blood pressure times heart rate) from baseline values. A linear mixed model was used to study the association between the outcome variable RPP and the type of laryngoscope used. RESULTS: The relative increase of the RPP at intubation was significantly smaller (i.e. 27%, P < 0.001) using videolaryngoscopy compared to the classic direct laryngoscopy. Cardiovascular responses were blunted by an additional 10.2% (P = 0.029), when the patient was on beta blockade. CONCLUSIONS: Our study shows less hemodynamic responses during endotracheal intubation using indirect videolaryngoscopy compared to classic direct laryngoscopy.

Transplacental transfer of remifentanil in the pregnant ewe.

BACKGROUND AND PURPOSE: While remifentanil can be used either during labour or fetal surgery, more should be known about the transplacental transfer of this opioid. The aim of this study was to investigate the placental transfer and haemodynamic effects of remifentanil after i.v. administration to pregnant ewes. EXPERIMENTAL APPROACH: Seven pregnant ewes received a continuous infusion of remifentanil (0.33 µg·kg⁻¹·min⁻¹) for 1 h, and maternal and fetal arterial blood samples were drawn at regular intervals during and up to 1 h after the discontinuation of the infusion. Haemodynamic parameters were monitored continuously. Blood gas samples were drawn at baseline and once during the infusion. KEY RESULTS: Peak maternal remifentanil plasma levels of 4.0 ± 0.9 ng·mL⁻¹ (mean ± SD) and peak fetal plasma levels of 0.4 ± 0.3 ng·mL⁻¹ were obtained. Remifentanil plasma levels dropped rapidly after the discontinuation of the infusion. The continuous infusion of remifentanil did not result in significant maternal or fetal haemodynamic changes. CONCLUSIONS AND IMPLICATIONS: Remifentanil rapidly passes through the placenta of pregnant ewes and although remifentanil concentrations stay significantly lower in the fetus compared with those in the mother, remifentanil can be detected in significant amounts in the fetus.

Predictors of physical and emotional recovery 6 and 12 months after surgery.

BACKGROUND: A proportion of patients do not recover fully from surgery or they develop chronic postsurgical pain. The aim of this study was to examine the incidence and predictors of unfavourable long-term outcome after surgery using a prospective cohort design. METHODS: Some 401 patients undergoing various elective surgical procedures filled in the RAND 36-item Health Survey 1.0 health-related quality-of-life questionnaire before operation and at 6 and 12 months of follow-up to assess changes in pain, physical functioning, mental health and vitality. Preoperative psychological assessment was obtained. RESULTS: Most patients showed improvement in the various aspects of health-related quality of life after surgery, but a considerable proportion (14-24 per cent) still showed deterioration at 6 and 12 months. Multivariable linear regression analysis identified acute postoperative pain, duration of the operation and preoperative physical condition as the most important predictors of long-term pain and physical functioning. Preoperative surgical fear also had a small but significant contribution. The main predictors of mental health and vitality were physical condition before surgery, surgical fear and optimism. CONCLUSION: Up to a quarter of patients experienced suboptimal recovery after surgery. Both somatic and psychological factors were associated with the long-term outcome. Optimal recovery could be promoted by effective interventions on malleable factors.

Systemic but not local administration of retinoic acid reduces early transcript levels of pro-inflammatory cytokines after experimental spinal cord injury.

Early rises of pro-inflammatory cytokines play a key role in tissue damage and has detrimental consequences for functional outcome after spinal cord injury (SCI). All-trans retinoic acid (RA) has been shown to be a therapeutic agent reducing cytokine expression in vitro, but its use may be limited due to adverse side effects associated with systemic delivery. Local delivery of RA may circumvent adverse side effects, but may simultaneously reduce the therapeutic benefits of the therapy. Here, we investigated whether local or systemic RA treatment differentially affected pro-inflammatory cytokine expression early after rat SCI. Pro-inflammatory cytokines IL-1ß, IL-6 and TNFα were investigated at 6h after moderate contusion injury of the thoracic (T9) spinal cord, when mRNA levels are known to peak. Rats were either treated with intrathecal RA (0, 2.5, 10, or 100ng) or received an intraperitoneal injection of RA (15mg/kg bodyweight). Surprisingly intrathecal RA up to amounts of 100ng did not attenuate SCI-induced increases in gene-expression of pro-inflammatory cytokines. In contrast, intraperitoneal RA rendered a 60%, 35% and 58% reduction of IL-1ß, IL-6 and TNFα mRNA levels, respectively. Although local doses higher than 100ng RA may reduce pro-inflammatory cytokine gene-expression, such doses precipitate and possibly increase risks of adverse side effects. We conclude that in contrast to systemic delivery, intrathecal administration of RA up to doses of 100ng is ineffective in reducing early pro-inflammatory cytokine gene-expression. Future studies are required to investigate the effects of single intraperitoneal RA treatment on long-term SCI outcome.

Spinal anesthesia for a parturient with the triad of Currarino.

The triad of Currarino, also known as Currarino syndrome or complex, is a rare hereditary syndrome involving a bony sacral defect, an anorectal malformation and a presacral mass. Thus far, only 250 cases have been reported, but milder cases may not be recognized, and many cases may not be published. In addition to disorders of the gastrointestinal and urogenital tracts, sensory and motor deficits may be present. Currently, there are no reports of women with the triad of Currarino undergoing cesarean delivery with the use of neuraxial anesthesia. Neuraxial anesthesia in patients with congenital malformations of the spine may be complicated or contraindicated, depending on the level and severity of the anatomic abnormality. We present the case of a pregnant woman at 36 weeks of gestation who underwent uncomplicated neuraxial anesthesia for cesarean delivery. When neuraxial anesthesia is contemplated in such patients, they should first receive careful neurologic and radiologic evaluation.

Maternal cardiac arrest in early pregnancy.

A primigravid woman suffered a prolonged cardiac arrest at 18 weeks of gestation. Dilated ischemic cardiomyopathy was diagnosed. After recovery, the patient received an implantable cardioverter-defibrillator. At 38 weeks of gestation she had an elective caesarean delivery. Both mother and child had a favourable outcome. The effect of pregnancy on underlying cardiac disease and the management of maternal cardiac arrest with a pre-viable fetus are discussed. The importance of a multidisciplinary approach is emphasized. Continued neurodevelopmental assessment of the newborn is necessary to detect the long-term effects of fetal hypoxia in early pregnancy.

The prevalence of postoperative pain in a sample of 1490 surgical inpatients.

BACKGROUND AND OBJECTIVE: To measure the prevalence of postoperative pain, an assessment was made of 1490 surgical inpatients who were receiving postoperative pain treatment according to an acute pain protocol. METHODS: Measurements of pain (scores from 0 to 100 on a visual analogue scale) were obtained three times a day on the day before surgery and on days 0-4 postoperatively; mean pain intensity scores were calculated. Patients were classified as having no pain (score 0-5), mild pain (score 6-40), moderate pain (score 41-74) or severe pain (score 75-100). RESULTS: Moderate or severe pain was reported by 41% of the patients on day 0, 30% on days 1 and 19%, 16% and 14% on days 2, 3 and 4. The prevalence of moderate or severe pain in the abdominal surgery group was high on postoperative days 0-1 (30-55%). A high prevalence of moderate or severe pain was found during the whole of days 1-4 in the extremity surgery group (20-71%) and in the back/spinal surgery group (30-64%). CONCLUSION: We conclude that despite an acute pain protocol, postoperative pain treatment was unsatisfactory, especially after intermediate and major surgical procedures on an extremity or on the spine.

Evaluation of two different epidural catheters in clinical practice. narrowing down the incidence of paresthesia!

Although epidural anesthesia is considered safe, several complications may occur during puncture and insertion of a catheter. Incidences of paresthesia vary between 0.2 and 56%. A prospective, open, cohort-controlled pilot study was conducted in 188 patients, ASA I-III, age 19-87 years, scheduled for elective surgery and epidural anesthesia. We evaluated a 20 G polyamide (standard) catheter and a 20 G combined polyurethane-polyamide (new) catheter. Spontaneous reactions upon catheter-insertion, paresthesia on questioning, inadvertent dural or intravascular puncture, and reasons for early catheter removal were recorded. The incidence of paresthesia reported spontaneously was 21.3% with the standard catheter and 16.7% with the new catheter. Systematically asking for paresthesia almost doubled the paraesthesia rate. Intravascular cannulation occurred in 5%. No accidental dural punctures occurred. An overall incidence of 13.3% of technical problems led to early catheter removal. The new catheter was at least equivalent to the standard regarding epidural success rate and safety : rate of paresthesia, intravascular and dural cannulation.

The CatWalk method: a detailed analysis of behavioral changes after acute inflammatory pain in the rat.

Experimental pain research is often complicated by the absence of an objective and detailed method to analyze behavioral changes. In the present study, acute pain was induced into the right knee of the rat (n=15) through the injection of 2mg carrageenan (CAR) in saline. A control group received vehicle injection into the knee (n=15). With the use of an automated quantitative gait analysis system, the CatWalk, it was possible to quantitatively analyze behavioral changes at post-injection time 2.5, 4, 24 and 48h. The CatWalk analysis of individual paw parameters like the intensity of the paw print or the time contact with the floor showed a significant effect after CAR injection into the knee. These CatWalk parameters were highly correlated with von Frey data and thus representative for the development of mechanical allodynia. Furthermore, detailed CatWalk analysis of the gait (i.e. coordinated interaction between left and right hindlimb) showed very fine, accurate and significant coordination changes in the experimental rats from 4h post-injection. In conclusion, the CatWalk method allows an objective and detailed detection of both pain-induced gait adaptations as well as the development of mechanical allodynia in an acute inflammatory pain model.

Effects of cafedrine/theodrenaline, etilefrine and ephedrine on uterine blood flow during epidural-induced hypotension in pregnant sheep.

INTRODUCTION: Maternal hypotension is a major concern in obstetric anesthesia, and concerns have been raised about standard vasopressor therapy with ephedrine. Therefore, we evaluated the maternal and fetal hemodynamic effects of two potential alternatives to ephedrine. METHODS: Hypotension was induced by epidural administration of lidocaine in 6 chronically instrumented pregnant ewes (at 118-122 days of gestation, term 145 days). Three treatments were studied: 25 mg ephedrine, 5 mg etilefrine and 100 mg cafedrine/5 mg theodrenaline (C/T) intravenously. Mean fetal and maternal blood pressure and heart rate, uterine blood flow, as well as fetal and maternal arterial blood gases were recorded for 60 min. RESULTS: All three vasopressors increased maternal blood pressure, accompanied by a significant increase in uterine blood flow. C/T caused marked maternal tachycardia, whereas ephedrine decreased maternal heart rate. Maternal and fetal blood gases did not change during any of the three treatment regimens. CONCLUSION: All three vasopressors restored maternal blood pressure and uterine blood flow after epidurally induced maternal hypotension. However, restoration of uterine perfusion was delayed and less pronounced with C/T.

Assessment of volume preload on uteroplacental blood flow during epidural anaesthesia for Caesarean section.

BACKGROUND AND OBJECTIVE: Epidural and spinal anaesthesia are the preferred mode of anaesthesia for Caesarean section. Volume preloading is recommended to prevent maternal hypotension and a reduction in uteroplacental blood flow, although positive effects of volume preloading on maternal cardiac output and arterial pressure are debatable. Doppler measurements of the umbilical artery beyond deriving pulsatility indices are not routinely performed. METHODS: After Institutional Review Board approval and written informed consent, 14 consecutiVe women with epidural anaesthesia for Caesarean section received either hydroxyethyl starch 500 mL or gelatine 500 mL. Haemodynamic variables monitored were maternal arterial pressure, maximal blood flow velocity and pulsatility indices of the uterine artery derived from Doppler measurements. CONCLUSIONS: Maternal arterial pressure and pulsatility indices in both groups did not change from baseline after intravenous colloid infusion. However, uterine blood flow increased significantly in both groups. The effectiveness of volume preloading may therefore be better described by changes in maximum uterine blood flow velocity than by pulsatility indices or maternal arterial pressure.

Epidural local anesthetics: a novel treatment for fetal growth retardation?

BACKGROUND: Chronically compromised uterine perfusion may lead to placental insufficiency and subsequent intrauterine growth restriction (IUGR). Various therapeutic approaches (e.g. vasodilators, low-dose aspirin, intravenous glucose infusion, and hemodilution) are often of limited efficacy. Local anesthetics have been shown to improve placental blood flow in pre-eclamptic women. We hypothesized that epidural administration of local anesthetics might improve outcome in IUGR independent of the underlying cause. In preparation for a clinical trial to test this hypothesis, we performed a pilot study in 10 patients. METHODS: After approval of the study protocol, 10 pregnant women presenting with oligohydramnios and IUGR were included in the study. In addition to our standard protocol (magnesium, glucose, betamethasone), each patient received an epidural catheter (T10/T12) with continuous infusion of bupivacaine 0.175% at a rate of 5 ml/h. Uteroplacental circulation was monitored by Doppler sonography and the amount of amniotic fluid was estimated daily. RESULTS: Epidural insertion and infusion was performed without complications. Four patients continued to deteriorate rapidly, amniotic fluid volume did not change and uterine artery pulsatility index (PI) tended to increase. In the remaining 6 patients the clinical status stabilized, amniotic fluid volume tended to increase and uterine artery PI tended to decrease during treatment. This improvement was associated with a prolonged interval to cesarean section and increased infant birth weight. CONCLUSION: Our data suggest that, even if the underlying cause of IUGR is not pre-eclampsia, epidural local anesthetic administration might improve placental blood flow and be beneficial in a subgroup of patients. A clinical trial to test this hypothesis appears warranted.

Clinical efficacy of postoperative autologous transfusion of filtered shed blood in hip and knee arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) or total hip arthroplasty (THA) regularly results in postoperative requirement of blood transfusion. Because of the disadvantages of allogeneic blood transfusion (ABT) such as the risk of transfusion-associated infections, incompatibility-related transfusion fatalities, or immunomodulatory effects, a continuing effort to reduce allogeneic blood transfusion is important. For this purpose, the effect of reinfusion of drain blood, via a postoperative wound drainage and reinfusion system, on the need for allogeneic blood transfusion was evaluated. STUDY DESIGN AND METHODS: Using a prospective observational quality assessment design, we compared 135 patients scheduled for TKA or THA with a historic group of 96 patients. In the study group the Bellovac ABT autotransfusion system was used. The shed blood was returned either when 500 mL were collected or at most 6 hours after surgery. Compared were the preoperative, postoperative, and discharge hemoglobin, as well as the number of allogeneic blood transfusions. RESULTS: There were no statistical differences between preoperative, postoperative, and discharge hemoglobin levels. Autologous transfusion reduced the number of patients receiving ABT overall from 35 percent (control) to 22 percent (study). The decrease of allogeneic transfusion requirement was most significant after TKA: from 18 percent to 6 percent (p < 0.001). CONCLUSION: We conclude that the Bellovac ABT device reduces allogeneic blood transfusions in TKA and THA.