Preoperative acute hypervolemic hemodilution with hydroxyethylstarch: an alternative to acute normovolemic hemodilution?

Jehovah's Witness Needing Critical Care: A Narrative Review on the Expanding Arsenal

Present day Jehovah's Witness (JW) religion accounts for 8.5 million followers. A tenant feature of the JW faith is religious objection to transfusions of blood and blood products. Interpatient variability, as it pertains to blood and blood products may occur; hence, a confidential interview will determine which products individual may consent to (Marsh and Bevan, 2002). This belief and practice place great restrictions on treating medical professionals in scenarios of life-threatening anaemia and active haemorrhage. The review to follow explores the physiological and pathophysiological consequences of severe anaemia. Non-blood transfusion practices are explored, many of which are potentially lifesaving. Particular attention is drawn to the evolving science involving artificial oxygen carriers and their use in emergency situations. A greater safety profile ensures its future use amongst religious objectors to be greatly beneficial. Intravenous iron supplementation has enjoyed a lively debate within the critical care community. A review of recent systematic and meta-analysis supports its use in the ICU; however, more investigation is needed into the complementary use of hepcidin.

Perioperative management including dual cell salvage in a Jehovah's Witness patient undergoing major urological surgery

Complex surgery associated with major hemorrhage presents particular risks for Jehovah's Witnesses who do not accept transfusion of blood products. Intraoperative use of two cell saver machines simultaneously can maximize the yield of salvaged blood from both the operative field and from washed surgical swabs and can potentially be life-saving.

Effect of acute hypervolemic hemodilution of 6% hydroxyethyl starch 130/0.4 on the EC50 of propofol at two clinical endpoints in patients

Preoperative acute hypervolemic hemodilution (AHHD) is a technique used in anesthesia to reduce the number of blood cells lost during intraoperative bleeding. The aim of the present study was to evaluate the effect of the hypervolemic hemodilution of 6% hydroxyethyl starch 130/0.4 on the EC₅₀ of propofol at two clinical endpoints. A total of 20 patients undergoing AHHD following epidural anesthesia were studied, and 20 patients who did not receive hemodilution were used as a control group. All patients were American Society of Anesthesiologists grade I, aged 20-40 years and undergoing hip arthroplasty surgery. In the AHHD group, 10 ml/kg lactated Ringer's solution was infused over 20 min at the same time as the epidural test dose. The infusion was followed by the infusion of 6% hydroxyethyl starch 130/0.4 over 30 min. Patients in the control group received 10 ml/kg Ringer's solution over 50 min. Propofol was then delivered by a Diprifusor target-controlled infusion. The predicted blood and effect-site propofol concentrations were recorded at loss of consciousness (LOC) and return of consciousness (ROC). Probit analysis was used to estimate the values for predicted blood and effect-site concentrations at the two clinical endpoints. The results showed that the potency of propofol was decreased during AHHD. Compared with the controls, the predicted blood and effect-site concentrations of propofol at LOC were higher in patients of the hemodilution group, resulting in higher EC₅₀ values (P=0.001 and 0.025, respectively). At ROC, the effect-site EC₅₀ was 2.9 µg/ml [95% confidence interval (CI), 2.8-3.0] in hemodilution patients and 2.5 µg/ml (95% CI, 2.2-2.6) in control patients (P=0.001). With AHHD, the LOC time was significantly longer and the propofol dose was higher, while ROC times were comparable. In conclusion, AHHD increases the requirement for propofol at LOC and prolongs LOC time. Patients with AHHD recovered consciousness at higher effect-site concentrations of propofol. Thus, the induction dose of propofol should be increased during AHHD.

Prolonged hypervolemic hemodilution decreases functional capillary density of ileal mucosa in pigs revealed by sidestream dark-field imaging

OBJECTIVE

Hemodilution changes the physical properties of blood by reducing its hematocrit and blood viscosity. We tested whether prolonged hypervolemic hemodilution (HHD) impairs functional capillary density (FCD) of ileal mucosa in healthy mechanically-ventilated pigs and if there is any correlation between changes in FCD of ileal and sublingual mucosas during HHD.

METHODS

Sixteen domestic female pigs were anesthetized, mechanically-ventilated, and randomly assigned to the HHD (20 ml/(kg∙h) Hartmann's solution for 3 h) or fluid restrictive (5 ml/(kg∙h) Hartmann's solution for 3 h) group. Microcirculations of sublingual and ileal mucosas via ileostomy were visualized using sidestream dark-field (SDF) imaging at baseline conditions (t=0 h) and at selected time intervals of fluid therapy (t=1, 2, and 3 h).

RESULTS

A significant decrease of ileal FCD (285 (278-292) cm/cm(2)) in the HHD group was observed after the third hour of HHD when compared to the baseline (360 (350-370) cm/cm(2)) (P<0.01). This trend was not observed in the restrictive group, where the ileal mucosa FCD was significantly higher after the third hour of fluid therapy as compared to the HHD group (P<0.01). No correlation between microhemodynamic parameters obtained from sublingual and ileal mucosas was found throughout the study.

CONCLUSIONS

Prolonged HHD established by crystalloid solution significantly decreased ileal villus FCD when compared to restrictive fluid regimen. An inappropriate degree of HHD can be harmful during uncomplicated abdominal surgery.

Pharmacokinetics of propofol in patients undergoing total hip replacement : effect of acute hypervolemic hemodilution

OBJECTIVE

The aim of the study was to investigate the effects of acute hypervolemic hemodilution (HHD) on the pharmacokinetics of propofol in patients undergoing total hip replacement.

METHODS

A total of 16 patients undergoing elective surgery for total hip replacement under general anesthesia in combination with epidural analgesia were randomly assigned to 2 groups: the control group (n = 8) or the HHD group (n = 8). All patients in both groups received lactated Ringer's solution before induction of general anesthesia. In the control group the conventional fluid replacement protocol was used. In the HHD group 4% succinylated gelatin was infused at the rate of 20 ml•kg(-1)BW•h(-1 )with a targeted hematocrit of 30. Anesthesia was induced with midazolam 0.04 mg•kg(-1), fentanyl 4 µg•kg(-1) and propofol 1.5 mg•kg(-1). Tracheal intubation was facilitated by infusion of succinylcholine 2 mg•kg(-1). Anesthesia was maintained with isoflurane, fentanyl, vecuronium and epidural analgesia. Electrocardiogram (ECG), blood pressure (BP), blood oxygen saturation (SpO(2)), partial pressure of end-tidal carbon dioxide (P(ET)CO(2)) and central venous pressure (CVP) were monitored continuously. Blood samples were taken at 1, 2, 4, 6, 10, 15, 30, 45, 60, 75, 90, 120, 150, 180, 240, 300 and 360 min after propofol administration to determine plasma concentrations of propofol by high performance liquid chromatography (HPLC).

RESULTS

Plasma propofol concentrations were significantly lower in the HHD group than in the control group at 1, 2, 4, 6 and 10 min after propofol administration (p < 0.01) while there were no significant differences in plasma propofol levels 15-360 min after administration of propofol (p > 0.05). In the HHD group the volume of distribution of the central compartment (V(C)) increased significantly, elimination half-life (T(1/2) (γ)) was significantly prolonged, the elimination rate constant (K(10)) and the whole-body clearance (CL) were significantly decreased compared with the control group (p < 0.01 or 0.05). There were no significant differences of the half-life of the fast distribution phase (T(1/2) (α)), half-life of the slower distribution phase (T(1/2) (β)), K(12), K(21), K(13), K(31) and the area under the curve (AUC) (p > 0.05). The pharmacokinetic profile of propofol is best described by a three-compartment model in both groups using minimal Akaike information criteria (AIC).

CONCLUSION

Acute HHD increases V(C), prolongs the T(1/2) (γ), and decreases K(10) and CL, which suggests that care must be taken when propofol is used in patients undergoing HHD. The induction dose should be increased, but the maintenance dose should be decreased. The time to emergency from anesthesia will likely be prolonged, especially in patients receiving prolonged continuous infusions.

The influence of perioperative blood transfusion on intrahepatic recurrence after curative resection of hepatocellular carcinoma

OBJECTIVE

This study retrospectively evaluated the association between perioperative blood transfusion and intrahepatic recurrence in patients with hepatocellular carcinoma (HCC) who had undergone curative hepatic resections.

METHODS

Hepatic resection was performed with curative intent in 195 patients with primary HCC between 1985 and 1996. Patients who had received perioperative blood transfusion (transfused group: n = 117) and those who had no perioperative blood transfusion (nontransfused group: n = 78) were compared in terms of conventional prognostic variables and cancer-free survival by the univariate and multivariate analyses.

RESULTS

The 1-, 3-, and 5-yr cancer-free survival rates in the nontransfused and transfused groups were 83.4% and 67.9%, 43.0% and 36.7%, and 23.1% and 24.6%, respectively (p = 0.175). Multivariate analysis of prognostic factors in all patients revealed that vascular invasion, tumor size (> or =5 cm), and Child's class were independent factors for intrahepatic recurrence. Further analyses in various stratified groups showed that perioperative blood transfusion was an independent predictor of prognosis in HCC patients with portal vein invasion (RR: 2.8, p = 0.0038). The 1-, 3-, and 5-yr survival rates in the nontransfused and transfused groups with portal vein invasion were 71.9% and 41.6%, 54.5% and 10.9%, and 26% and 0%, respectively (p = 0.0003).

CONCLUSIONS

We conclude that perioperative blood transfusions enhance the risk of intrahepatic recurrence of HCC in patients with portal vein invasion. As well, the more difficult surgery and the increased manipulation of the liver that occur in these cases create a greater possibility of tumor dissemination.