Blood Products, Crystalloids, and Rapid Infusion: An Experimental Study With Magnesium.

OBJECTIVES: Calcium and magnesium are concentration-dependent pro- and anticoagulant cofactors, and magnesium behaves similarly to calcium in the presence of citrate. The authors hypothesized that magnesium can cause clot formation (primary objective) when mixed with coagulation factor-containing blood products diluted with different crystalloids in a rapid- infuser reservoir. A secondary objective was the observation of any infuser alarms and stops in the event of clotting. DESIGN: An experimental in vitro study with blood products, crystalloids, magnesium, and calcium in a rapid infuser with a reservoir using a closed-loop system. SETTING: Anesthesia research laboratory at an urban academic tertiary medical center PARTICIPANTS: Not applicable. INTERVENTIONS: Exposure of fresh frozen plasma (FFP) and packed red blood cells alone (control) or in combination with either normal saline (NS), lactated Ringer's solution (LR), or Plasma-Lyte A (PL) to increasing concentrations of magnesium sulphate (MgSO4) up to 1 g. After each incremental MgSO4 change, the authors applied a specific pump-flow sequence in a closed-loop system with a rapid-infuser reservoir, and if no clot was observed, the authors incrementally added calcium chloride (CaCl2) up to 1 g. MEASUREMENTS AND MAIN RESULTS: Observation of macroscopic clot and time to event, as well as occurrence and type of any pump alarms or stops. LR experiments resulted in clot observation in the reservoir by a dedicated observer after MgSO4 275 ± 206 mg (95% confidence interval [CI], 9-541). Adding MgSO4 1 g in the NS, PL, or the control experiments did not result in clot observation. Only when CaCl2 166.7 ± 51.64 mg (95% CI, 112.0-22.01) was added to the combination of blood products alone or mixed with NS and PL, clotting occurred. The mean FFP volume was 281 ± 48.6 mL (range, 204-340 mL) and was not different between groups (p = 0.44). Pump alarms and stops were inconsistent. CONCLUSIONS: The addition of magnesium to a combination of LR with coagulation factor- containing blood products consistently resulted in a visible blood clot in the rapid-infuser reservoir in the authors' experimental setup. In addition to MgSO4 1 g in the control, NS, and PL experiments, CaCl2 is needed before a clot can be observed.

The Impact of Rapid Infuser Use on the Platelet Count, Platelet Function, and Hemostatic Potential of Whole Blood.

BACKGROUND: Rapid infusion pumps employing filters, roller pumps, and heat exchangers for the administration of blood products are not approved for platelets or cryoprecipitate. This technology may decrease platelet count and degrade coagulation proteins. The effect of rapid infusers on the hemostatic potential of whole blood is unknown. METHODS: Five units of low titer O+ whole blood were obtained from anonymous donors. Each unit was subjected to infusion by five different techniques: (1) gravity infusion without a filter, (2) gravity infusion with a filter, (3) Belmont rapid infuser at 70 mL/min, (4) Belmont at 100 mL/min, and (5) pressurized infusion with a pneumatic pressure bag and filter. After infusion, platelet count, platelet function, thrombin generation, and hemostatic potential were measured for each aliquot. Infusion techniques were compared, using gravity infusion without a filter as the control. RESULTS: There was a significant decrease in platelet count from baseline (168,000) in the BELMONT70 (97,000) and BELMONT100 (94,000) groups (P < 0.05). However, there were no differences in platelet function (all P > 0.20). While there were no differences in thromboelastography parameters between control and infusion models (all P > 0.20), there were significant increases in thrombin generation parameters by CAT in both the BELMONT70 and BELMONT100 groups (all P < 0.05). CONCLUSIONS: The use of a rapid infuser decreases the platelet count of WB but does not decrease platelet function or overall hemostatic potential. In fact, thrombin generation and thrombin potential are actually increased. Rapid infusers are safe for the transfusion of WB.

Postpartum hemorrhage: Anesthesia management.

As major stakeholders in the labor and delivery suite, obstetric anesthesiologists are frequently called upon to provide their unique skill sets and expertise to the management of postpartum hemorrhage, whether anticipated or not. Essential contributions of the anesthesia team ideally begin in the antenatal period with referral of women at high risk of postpartum hemorrhage to an outpatient obstetric anesthesia clinic where a tailored plan for both urgent or scheduled delivery for women with an anticipated complex delivery can be formulated. Maternal safety can be greatly improved if comorbidities are identified early and strategies to address these issues are proposed and known by the obstetric anesthesia team. Participation of the obstetric anesthesiology team is crucial in the development of systematic approaches that are customized to each institution and should comprise the creation and dissemination of algorithms and guidelines that are anesthesia specific, including detailed protocols for the labor and delivery unit and operating rooms, at large. Because management of postpartum hemorrhage requires a coordinated team effort, and may not always be planned, the anesthesia team should be prepared at all times to provide the appropriate anesthetic management and advanced cardiovascular support. The involvement of the anesthesia team should not only be limited to the immediate intrapartum period, but should also extend to the postpartum period where adequate anesthetic/analgesic plans will enhance maternal safety and recovery.

Significant air embolism: A possibility even with collapsible intravenous fluid containers when used with rapid infuser system.

Significant venous air embolism may develop acutely during the perioperative period due to a number of causes such as during head and neck surgery, spinal surgery, improper central venous and haemodialysis catheter handling, etc. The current trend of using self collapsible intravenous (IV) infusion bags instead of the conventional glass or plastic bottles has several advantages, one of thaem being protection against air embolism. We present a 56-year-old man undergoing kidney transplantation, who developed a near fatal venous air embolism during volume resuscitation with normal saline in collapsible IV bags used with rapid infuser system. To our knowledge, this problem with collapsible infusion bags has not been reported earlier.