William C. Oliver

Efficacy of a simple intraoperative transfusion algorithm for nonerythrocyte component utilization after cardiopulmonary bypass.

Background Abnormal bleeding after cardiopulmonary bypass (CPB) is a common complication of cardiac surgery, with important health and economic consequences. Coagulation test–based algorithms may reduce transfusion of non-erythrocyte allogeneic blood in patients with abnormal bleeding. Methods The authors performed a randomized prospective trial comparing allogeneic transfusion practices in 92 adult patients with abnormal bleeding after CPB. Patients with abnormal bleeding were randomized to one of two groups: a control group following individual anesthesiologist’s transfusion practices and a protocol group using a transfusion algorithm guided by coagulation tests. Results Among 836 eligible patients having all types of elective cardiac surgery requiring CPB, 92 patients developed abnormal bleeding after CPB (incidence, 11%). The transfusion algorithm group received less allogeneic fresh frozen plasma in the operating room after CPB (median, 0 units; range, 0–7 units) than the control group (median, 3 units; range, 0–10 units) (P = 0.0002). The median number of platelet units transfused in the operating room after CPB was 4 (range, 0–12) in the algorithm group compared with 6 (range, 0–18) in the control group (P = 0.0001). Intensive care unit (ICU) mediastinal blood loss was significantly less in the algorithm group. Multivariate analysis demonstrated that transfusion algorithm use resulted in reduced ICU blood loss. The control group also had a significantly greater incidence of surgical reoperation of the mediastinum for bleeding (11.8%vs. 0%;P = 0.032). Conclusions Use of a coagulation test–based transfusion algorithm in cardiac surgery patients with abnormal bleeding after CPB reduced non-erythrocyte allogeneic transfusions in the operating room and ICU blood loss.

Cardiac Risk of Noncardiac Surgery after Percutaneous Coronary Intervention with Drug-eluting Stents

Background:The American College of Cardiology released a scientific advisory that included a recommendation to delay elective of noncardiac surgery (NCS) for 1 yr after percutaneous coronary intervention (PCI) with a drug-eluting stent (DES). Methods:This single-center, retrospective study examined the risk for complications of NCS performed within 2 yr after DES placement and examined whether this risk changed based on the time between procedures. The primary endpoint was major adverse cardiac events (MACEs) during the hospitalization for NCS. Bleeding events were analyzed as a secondary endpoint. Results:From April 22, 2003, to December 31, 2006, a total of 520 patients underwent NCS within 2 yr after PCI with a DES at Mayo Clinic. The majority, 84%, of the DES placed were Cypher stents. The frequency of MACE was not found to be significantly associated with the time between PCI and NCS (rate of MACEs 6.4, 5.7, 5.9, and 3.3% at 0–90, 91–180, 181–365, and 366–730 days after PCI with DES, respectively; P = 0.727 for comparison across groups). Characteristics found to be associated with MACEs in univariate analysis were advanced age (P = 0.031), emergent NCS (P = 0.006), shock at time of PCI (P = 0.035), previous history of myocardial infarction (P = 0.046), and continuation of a thienopyridine (ticlopidine or clopidogrel) into the preoperative period (P = 0.040). The rate of transfusion did not seem to be associated with antiplatelet therapy use. Conclusions:The risk of MACEs with NCS after DES placement was not significantly associated with time from stenting to surgery, but observed rates of MACEs were lowest after 1 yr.

Time and cardiac risk of surgery after bare-metal stent percutaneous coronary intervention

Background:The duration of time that elective noncardiac surgery (NCS) should be delayed after percutaneous coronary intervention (PCI) with bare metal stents (BMSs) is unknown. Methods:This large, single-center, retrospective study examined the relation between complication rate in patients with BMSs undergoing NCS and the duration of time between PCI and NCS. Primary endpoints included in-hospital major adverse cardiac events (death, myocardial infarction, stent thrombosis, or repeat revascularization with either coronary artery bypass grafting or PCI of the target vessel) and bleeding events. The relation between the events and the timing of noncardiac surgery after PCI with BMS was assessed using univariate analysis and multiple logistic regression. Results:From January 1, 1990, to January 1, 2005, a total of 899 patients were identified. The frequency of major adverse cardiac events was 10.5% when NCS was performed less than 30 days after PCI with BMS, 3.8% when NCS was performed between 31 and 90 days after PCI with BMS, and 2.8% when NCS was performed more than 90 days after PCI with BMS. In univariate and multivariate analyses, a shorter time interval between PCI with BMS and noncardiac surgery was significantly associated with increased incidence of major adverse cardiac events (univariate: P < 0.001; odds ratio = 4.0; 95% confidence interval, 2.0–8.3; multivariate: P = 0.006; odds ratio = 3.2; 95% confidence interval, 1.5–6.9). Bleeding events were not associated with time between PCI with BMS and NCS or with the use of antiplatelet therapy in the week before NCS. Conclusions:The incidence of major adverse cardiac events is lowest when NCS is performed at least 90 days after PCI with BMS.

Predictors of blood transfusions in spinal instrumentation and fusion surgery

STUDY DESIGN A retrospective review of 244 adult spine instrumentation and fusion surgery cases (1994-1995) from one institution. OBJECTIVES To ascertain the predictors of blood transfusions for adult patients undergoing different types of multilevel spine surgery. SUMMARY OF BACKGROUND DATA Blood loss and transfusion requirements during and after multilevel spine surgeries have always been perceived as great. Identifying the predictors of blood transfusion with this type of surgery may aid in reducing the amount of blood loss and the transfusion requirements. METHODS The charts of 244 adult patients who underwent multilevel spine surgery from January 1994 to July 1995 were retrospectively reviewed. RESULTS A large percentage of patients required blood transfusion. The significant determinants for increased amounts of allogeneic red blood cell units transfused on the day of surgery using linear multiple regression modeling were low preoperative hemoglobin concentration, tumor surgery, increased number of posterior levels surgically fused, history of pulmonary disease, decreased amount of autologous blood available, and no use of the Jackson table (R2 = 0. 63). The significant determinants for an increased amount of autologous red blood cell units transfused on the day of surgery using linear multiple regression modeling were increased autologous red blood cells available, low preoperative hemoglobin concentration, and increased number of posterior levels surgically fused (R2 = 0. 60). CONCLUSION The need for transfusion is associated with multiple factors, suggesting that a multifaceted, integrated approach may be necessary to reduce this risk.

Outcome Following Posterior Fossa Craniectomy in Patients in the Sitting or Horizontal Positions

Controversy continues to surround the use of the sitting position for neurosurgical procedures. This retrospective review of 579 posterior fossa craniectomies performed over a 4-yr period from 1981 through 1984 examines outcome following these procedures performed with the patients in cither the sitting (n = 333) or horizontal (supine, prone, lateral, park bench) (n = 246) position. Multiple preoperative, intraoperative, and postoperative variables were analyzed. Venous air embolism occurred significantly more often in patients in the sitting position (45% versus 12%). However, no morbidity or mortality was attributed to venous air embolism. The incidence of hypotension with positioning was not different by position (19% in the sitting patients and 24% in the horizontal patients). Average blood replacement was significantly lower in the sitting patients (359 ml versus 507 ml), and the incidence of transfusion of greater than two units of blood was significantly higher in the horizontal patients (13% versus 3%). Postoperative cranial nerve function was significantly better in patients in the sitting group as compared to those in the horizontal group. The incidence of perioperative cardiopulmonary complications was not different between groups. These outcome data suggest that there are potential advantages and disadvantages of both the sitting and horizontal positions without supporting a significantly increased morbidity or mortality associated with either position.

Plasma Tranexamic Acid Concentrations During Cardiopulmonary Bypass

Although tranexamic acid is used to reduce bleeding after cardiac surgery, there is large variation in the recommended dose, and few studies of plasma concentrations of the drug during cardiopulmonary bypass (CPB) have been performed. The plasma tranexamic acid concentration reported to inhibit fibrinolysis in vitro is 10 &mgr;g/mL. Twenty-one patients received an initial dose of 10 mg/kg given over 20 min followed by an infusion of 1 mg · kg−1 · h−1 via a central venous catheter. Two patients were removed from the study secondary to protocol violation. Perioperative plasma tranexamic acid concentrations were measured with high-performance liquid chromatography. Plasma tranexamic acid concentrations (&mgr;g/mL; mean ± sd [95% confidence interval]) were 37.4 ± 16.9 (45.5, 29.3) after bolus, 27.6 ± 7.9 (31.4, 23.8) after 5 min on CPB, 31.4 ± 12.1 (37.2, 25.6) after 30 min on CPB, 29.2 ± 9.0 (34.6, 23.8) after 60 min on CPB, 25.6 ± 18.6 (35.1, 16.1) at discontinuation of tranexamic acid infusion, and 17.7 ± 13.1 (24.1, 11.1) 1 h after discontinuation of tranexamic acid infusion. Four patients with renal insufficiency had increased concentrations of tranexamic acid at discontinuation of the drug. Repeated-measures analysis revealed a significant main effect of abnormal creatinine concentration (P = 0.02) and time (P < 0.001) on plasma tranexamic acid concentration and a significant time × creatinine concentration interaction (P < 0.001).

A prospective, randomized comparison of cerebral venous oxygen saturation during normothermic and hypothermic cardiopulmonary bypass.

Recent reports have described cerebral venous oxygen desaturation during and after rewarming from hypothermic cardiopulmonary bypass. Additionally, patients undergoing normothermic cardiopulmonary bypass may be at higher risk for neurologic injury. This study was designed to determine whether patients undergoing normothermic cardiopulmonary bypass are at increased risk for sustained cerebral desaturation. Fifty-two patients undergoing first-time coronary artery bypass grafting were randomized to receive normothermic (37 degrees C, n = 26) or hypothermic (27 degrees C, n = 26) cardiopulmonary bypass. The anesthetic was standardized and alpha-stat pH management was used. A 4F oximetric catheter was placed in the jugular bulb and cerebral venous and radial arterial blood were sampled. Oxygen partial pressure and saturation were measured at six intervals from cerebral venous blood and from radial arterial blood. Patients receiving normothermic cardiopulmonary bypass had lesser values of oxygen partial pressure and saturation in cerebral venous blood than patients subjected to hypothermia during the first 40 minutes of bypass. Cerebral venous desaturation (oxygen saturation in cerebral venous blood of 50% or less) was observed in 54% of patients in the normothermic group and 12% of patients in the hypothermic group during cardiopulmonary bypass. In the normothermic group, cerebral desaturation occurred primarily in early bypass (14 of 26). The three episodes of desaturation in the hypothermic group occurred during rewarming. During cardiopulmonary bypass, the arteriovenous oxygen content difference was greater in the normothermic group than in that in the hypothermic group, suggesting higher oxygen consumption. Differences in glucose utilization during early cardiopulmonary bypass between the groups was also detected. One patient in the hypothermic group had an embolic stroke and subsequently died. There were no other perioperative strokes or deaths in the study population. The present study demonstrates that patients undergoing normothermic cardiopulmonary bypass are at greater risk for cerebral desaturation. Because it is a global assessment, cerebral venous oxygen saturation may be insensitive to focal ischemic events. It remains to be seen whether these differences in cerebral physiologic states translate into differences in clinical outcome.

Does Low-dose Droperidol Administration Increase the Risk of Drug-induced QT Prolongation and Torsade de Pointes in the General Surgical Population?

Background:The US Food and Drug Administration issued a black box warning regarding the use of droperidol and the potential for torsade de pointes (TdP). Methods:The primary objective of this retrospective study was to determine whether low-dose droperidol administration increased the incidence of TdP in the general surgical population during a 3-yr time period before and after the Food and Drug Administration black box warning. A random sample of 150 surgical patients during each time interval was selected to estimate the droperidol use for each time period. Results:During the time period before the black box warning (July 1, 1998 to June 30, 2001), 2,321/139,932 patients (1.66%) had QT prolongation, TdP, or death within 48 h after surgery. We could identify no patients who clearly developed TdP before the black box warning. There was one patient for whom the cause of death could not positively be ruled out as due to TdP. In the time period after the black box warning (July 1, 2002 to June 30, 2005), 2,207 patients (1.46%) had documented QT prolongation, TdP, or death within 48 h after surgery, including only two cases (<0.1%) of TdP. The incidence of droperidol exposure was approximately 12% (exact 95% confidence interval, 7.3–18.3%) before the black box warning and 0% after placement of the black box warning on droperidol. Therefore, we estimate that approximately 16,791 patients (95% confidence interval, 10,173–25,607) were exposed to droperidol, none of whom experienced documented TdP. Conclusions:This indicates that the Food and Drug Administration black box warning for low dose droperidol is excessive and unnecessary.

Morbidity and Mortality in the Use of Electroconvulsive Therapy

There are a few large studies of the morbidity and mortality of electroconvulsive therapy (ECT). To add data to this literature, we performed a retrospective review of all the patients who underwent ECT at our institution between January 1, 1988, through December 31, 2001. We identified 2,279 patients who were given 17,394 ECT treatments during their first series. The median number of treatments received per patient was 7. Twenty-one patients (0.92%) experienced a complication at some time during their first series of ECT treatments. Cardiac complications, mostly arrhythmias, constituted the majority. However, none of the complications caused permanent injury, and none of the patients died during or immediately after ECT. There were 18 deaths within 30 days of the final treatment, none related to ECT. These data are concordant with those of other published large series, and we conclude that ECT is an extremely safe procedure.

Comparison of Blood-conservation Strategies in Cardiac Surgery Patients at High Risk for Bleeding

Background: Aprotinin and tranexamic acid are routinely used to reduce bleeding in cardiac surgery. There is a large difference in agent price and perhaps in efficacy. Methods: In a prospective, randomized, partially blinded study, 168 cardiac surgery patients at high risk for bleeding received either a full-dose aprotinin infusion, tranexamic acid (10-mg/kg load, 1-mg · kg−1 · h−1 infusion), tranexamic acid with pre–cardiopulmonary bypass autologous whole-blood collection (12.5% blood volume) and reinfusion after cardiopulmonary bypass (combined therapy), or saline infusion (placebo group). Results: There were complete data in 160 patients. The aprotinin (n = 40) and combined therapy (n = 32) groups (data are median [range]) had similar reductions in blood loss in the first 4 h in the intensive care unit (225 [40–761] and 163 [25–760] ml, respectively;P = 0.014), erythrocyte transfusion requirements in the first 24 h in the intensive care unit (0 [0–3] and 0 [0–3] U, respectively;P = 0.004), and durations of time from end of cardiopulmonary bypass to discharge from the operating room (92 [57–215] and 94 [37, 186] min, respectively;P = 0.01) compared with the placebo group (n = 43). Ten patients in the combined therapy group (30.3%) required transfusion of the autologous blood during cardiopulmonary bypass for anemia. Conclusions: The combination therapy of tranexamic acid and intraoperative autologous blood collection provided similar reduction in blood loss and transfusion requirements as aprotinin. Cost analyses revealed that combined therapy and tranexamic acid therapy were the least costly therapies.