Swen N. Piper

The Influence of Allogeneic Red Blood Cell Transfusion Compared with 100% Oxygen Ventilation on Systemic Oxygen Transport and Skeletal Muscle Oxygen Tension After Cardiac Surgery: Retracted

In this study we investigated the effects of allogeneic red blood cell (RBC) transfusion on tissue oxygenation compared with those of 100% oxygen ventilation by using systemic oxygen transport variables and skeletal muscle oxygen tension (PtiO2). Fifty-one volume-resuscitated, mechanically ventilated patients with a nadir hemoglobin concentration in the range from 7.5 to 8.5 g/dL after elective coronary artery bypass grafting were allocated randomly to receive 1 unit (transfusion 1; n = 17) or 2 units (transfusion 2; n = 17) of allogeneic RBCs and ventilation with 40% oxygen or pure oxygen ventilation (100% oxygen; n = 17) and no allogeneic blood for 3 hours. Invasive arterial and pulmonary artery pressures and calculations of oxygen delivery (oxygen delivery index) and consumption indices (oxygen consumption index) were documented at 30-min intervals. PtiO2 was measured continuously by using implantable polarographic microprobes. Systemic oxygen transport variables and PtiO2 were similar between groups at baseline. The oxygen delivery index increased significantly with transfusion of allogeneic RBCs and 100% oxygen ventilation, whereas the oxygen consumption index remained unchanged. Oxygen 100% ventilation increased PtiO2 significantly (from 24.0 +/- 5.1 mm Hg to 34.2 +/- 6.2 mm Hg), whereas no change was found after transfusion of allogeneic RBCs. Peak PtiO2 values were 25.2 +/- 5.2 mm Hg and 26.3 +/- 6.5 mm Hg in the transfusion 1 and 2 groups, respectively. Transfusion of stored allogeneic RBCs was effective only in improving systemic oxygen delivery index, whereas 100% oxygen ventilation improved systemic oxygen transport and PtiO2. This improved oxygenation status was most likely due to an increase in convective oxygen transport with a large driving gradient for diffusion of plasma-dissolved oxygen into the tissue.

Unexpected return of spontaneous circulation after cessation of resuscitation (Lazarus phenomenon)

Since 1982, more than 20 patients with return of spontaneous circulation after cessation of cardiopulmonary resuscitation (Lazarus phenomenon) have been published. We report on another case here. Such cases are probably underreported due to medicolegal concerns. After cessation of resuscitation, each patient should be further monitored for at least 10 min to detect a possible Lazarus phenomenon.

Influence of prophylactic use of pentoxifylline on postoperative organ function in elderly cardiac surgery patients.

ObjectiveTo study the effects of pretreatment with pentoxifylline before cardiac surgery on postoperative organ function in elderly patients (>80 yrs) undergoing cardiac surgery. DesignProspective, randomized, placebo-controlled study. SettingTwo-day clinical investigation in an intensive care unit of a university-affiliated hospital. PatientsForty elderly patients (age >80 yrs) undergoing first-time elective aortocoronary bypass grafting. InterventionsIn 20 patients, pentoxifylline (loading bolus of 300 mg followed by a continuous infusion of 1.5 mg·kg−1·hr−1 until the second postoperative day) was given after induction of anesthesia; another 20 patients received saline solution as placebo. Measurements and Main Results Concentrations of soluble adhesion molecules (soluble E-selectin, soluble vascular cell adhesion molecule-1, and soluble intercellular adhesion molecules) were measured to assess endothelial function. Liver function was evaluated by monoethylglycinexylidide test and by measuring &agr;-glutathione S-transferase plasma concentrations. Renal function was assessed by measuring serum creatinine and urine concentrations of &agr;-1-microglobulin. Splanchnic perfusion was assessed by monitoring intramucosal pH by using continuous tonometry. All measurements were performed before pentoxifylline infusion (T0), at the end of surgery (T1), 5 hrs after surgery (T2), and at the morning of the first (T3) and second (T4) postoperative day. Postoperative concentrations of all measured soluble adhesion molecules were significantly higher in the nontreated controls than in the pentoxifylline-treated patients. Monoethylglycinexylidide serum concentrations were significantly lower and abnormal (<50 ng/mL) postoperatively only in the untreated control patients. &agr;-Glutathione S-transferase increased in both groups with a significantly higher increase in the control group (from 3.2 ± 1.2 to 24.1 ± 4.2 ng/mL) than in the pentoxifylline-treated patients (from 3.8 ± 1.9 to 11.5 ± 2.1 ng/mL). Serum creatinine was unchanged in both groups, whereas &agr;-1-microglobulin increased significantly more in the control group than in the pentoxifylline-treated group. Intramucosal pH remained almost unchanged in the pentoxifylline patients (>7.35) but decreased significantly in the control group (5 hrs after surgery, intramucosal pH 7.29 ± 0.13). ConclusionsPretreatment of patients aged >80 yrs undergoing cardiac surgery with pentoxifylline attenuated deterioration of endothelial, renal, and liver function as seen in an untreated control group. Splanchnic perfusion also appears to be improved in the pentoxifylline-treated group. Whether pretreatment with pentoxifylline will improve outcome in this patient population remains to be elucidated.

Diltiazem may preserve renal tubular integrity after cardiac surgery.

PURPOSE To evaluate the influence of dopamine and diltiazem on renal function and markers for acute renal failure, including urinary alpha-glutathion s-transferase (alpha-GST), alpha-1-microglobulin (alpha(1)-MG) and N-acetyl-ss-glucosaminidase (ss-NAG) after extracorporeal circulation. METHODS In a randomized, placebo-controlled, double-blind trial we evaluated the efficacy of dopamine (2.5 micro g x kg(-1) x min(-1)), diltiazem (2 micro g x kg(-1) x min(-1)) or placebo administered over 48 hr postoperatively to maintain renal tubular integrity in 60 elective cardiac surgery patients. alpha-GST, alpha(1)-MG, ss-NAG, and creatinine clearance were measured from urine collected during surgery (T0), the first four hours (T1), 24 hr (T2) and 48 hr (T3) postoperatively. RESULTS Cumulative urine output in the diltiazem group (9.0 +/- 2.8 L) increased significantly compared with placebo (7.0 +/- 1.6 L), but not compared with dopamine (7.8 +/- 1.8 L). Creatinine clearance showed no significant intergroup differences. In all groups alpha(1)-MG increased from T0 to T3, but we found no significant intergroup differences. alpha-GST increased significantly from T0 to T3 in the placebo (2.1 +/- 1.8 to 11.4 +/- 8.6 micro g x L(-1)) and in the dopamine groups (2.7 +/- 1.8 to 13.6 +/- 14.9 micro g x L(-1)), but not in the diltiazem group (1.8 +/- 1.4 to 3.2 +/- 3.2 micro g x L(-1)). Forty-eight hours postoperatively alpha-GST was significantly lower in the diltiazem group than in both other groups. CONCLUSIONS Diltiazem stimulates urine output, reduces excretion of alpha-GST and ss-NAG and may be useful to maintain tubular integrity after cardiac surgery.

A comparison of urapidil, clonidine, meperidine and placebo in preventing postanesthetic Shivering

UNLABELLED This placebo-controlled study was performed to evaluate the efficacy of urapidil compared with clonidine and meperidine in preventing postanesthetic shivering, which is common after anesthesia administration and may be very distressing. We studied 120 patients undergoing elective abdominal or orthopedic surgery under standardized general anesthesia. After surgery, patients were randomly assigned to one of four groups (each group n = 30) using a double-blinded protocol: Group A received 0.2 mg/kg urapidil; Group B, 3 microg/kg clonidine; Group C, 0.4 mg/kg meperidine; and Group D, saline 0.9% as placebo. Postanesthetic shivering was scored by using a five-point scale. Clonidine and meperidine significantly reduced the incidence and the severity of shivering in comparison with placebo, whereas there were no significant differences between the urapidil and placebo groups. Both clonidine and meperidine caused a significantly prolonged emergence time (13.4 +/- 5.8 and 13. 3 +/- 5.0 min, respectively) compared with placebo (10.4 +/- 5.3 min) and urapidil (11.4 +/- 2.9 min). We confirmed that both clonidine and meperidine are effective in preventing postanesthetic shivering, whereas urapidil, in our setting and dosage, was not effective. Patients who received clonidine or meperidine had a prolonged emergence time. In the dosage used, urapidil seems to be unable to prevent postanesthetic shivering. IMPLICATIONS Shivering (irregular muscle activity) is common after surgery and anesthesia. This study compared urapidil (an antihypertensive drug) as a prophylaxis with two established antishivering drugs (meperidine and clonidine) and placebo. In the dosage used, we were unable to show a significant benefit of urapidil.

Hepatocellular integrity after parenteral nutrition: comparison of a fish-oil-containing lipid emulsion with an olive-soybean oil-based lipid emulsion

Background and objective Parenteral nutrition including lipids might be associated with liver disease. The cause leading to parenteral nutrition-related liver dysfunction remains largely unknown but is likely to be multifactorial. The study was performed to assess the effects of a lipid emulsion based on soybean oil, medium-chain triglycerides, olive and fish oil (SMOFlipid20%) compared with a lipid emulsion based on olive and soybean oil on hepatic integrity. Methods In a prospective, randomized, double-blinded trial, 44 postoperative patients with an indication for parenteral nutrition were allocated to one of two regimens: group A (n = 22) received SMOFlipid, group B (n = 22) a lipid emulsion based on olive and soybean oil for 5 days. Aspartate aminotransferase, alanin-aminotransferase, and serum alpha-glutathion S-transferase were measured before the start of parenteral nutrition (d0), at day 2 (d2), and day 5 (d5) after the start of parenteral nutrition. The significance level was defined at a P value of less than 0.05. Results There was no significant difference at d0, but at d2 and d5, significantly lower aspartate aminotransferase (d2: group A: 27 ± 13 vs. group B: 47 ± 36 U l−1; d5: A: 31 ± 14 vs. B: 56 ± 45 U l−1), alanin-aminotransferase (d2: A: 20 ± 12 vs. B: 42 ± 39 U l−1; d5: A: 26 ± 15 vs. B: 49 ± 44 U l−1), and α-glutathion S-transferase levels (d2: A: 5 ± 6 vs. B: 17 ± 21 U l−1; d5: A: 6 ± 7 vs. B: 24 ± 27 μg l−1) were found in soybean oil, medium-chain triglycerides, olive and fish oil group compared with the control group. Conclusion Hepatic integrity was well retained with the administration of SMOFlipid whereas in patients receiving a lipid emulsion based on olive and soybean oil liver enzymes were elevated indicating a lower liver tolerability.

RETRACTED: Evaluation of a New Platelet Function Analyzer in Cardiac Surgery: A Comparison of Modified Thromboelastography and Whole-Blood Aggregometry

OBJECTIVES Impaired hemostasis of multiple etiologies are often present in patients undergoing cardiopulmonary bypass (CPB) surgery. Platelet dysfunction is considered to be important in the early postoperative period. Therefore, a new whole-blood platelet function analyzer was compared with thromboelastography in predicting postoperative hemostatic outcomes as measured by blood loss and blood product use. DESIGN Prospective study. SETTING Teaching hospital. PARTICIPANTS The study enrolled 54 patients scheduled for coronary artery bypass surgery with CPB. INTERVENTIONS Coagulation and platelet function were assessed preoperatively, after CPB, at 3 hours, and at 24 hours after surgery by using thromboelastography and impedance aggregometry. Patients were divided into a transfused and nontransfused group on the basis of postoperative transfusion requirements. Postoperative blood loss and requirements of blood transfusions were documented until 24 hours postoperatively. MEASUREMENTS AND MAIN RESULTS Twenty-five patients (46%) received postoperative blood transfusions. Impaired hemostasis occurred after CPB detected by thromboelastography (p < 0.01) and impedance aggregometry (p < 0.01). In contrast to thromboelastography, preoperative adenosine diphosphate-mediated aggregometry correlated with postoperative requirements for blood transfusion (Spearman r = -0.302, p < 0.05) and was significantly lower in patients receiving allogeneic blood transfusion compared with nontransfused patients (p < 0.05). Neither aggregometry nor thromboelastography was correlated with postoperative blood loss. CONCLUSION Impedance aggregometry as well as thromboelastography are able to detect impaired hemostasis after CPB. In contrast to thromboelastography, aggregometry using a new whole-blood aggregometer identified patients with a reduced risk for postoperative transfusion requirements.

RETRACTED: Influence of prolonged cardiopulmonary bypass times on splanchnic perfusion and markers of splanchnic organ function

BACKGROUND Cardiopulmonary bypass (CPB) is known to have considerable negative impact on perfusion and organ function. The effects of the duration of CPB on markers of splanchnic organ function was studied. METHODS Consecutive patients undergoing elective aorto-coronary bypass grafting with CPB times (CPBT) of either less than 70 minutes (n = 15) or more than 80 minutes (n = 15) were prospectively studied. Splanchnic perfusion was assessed by measuring arterial and gastric mucosal PCO2 and calculating PCO2gap. Hepatic function was evaluated by monoethylglycinexylidide (MEGX) test and by measuring alpha-glutathione S-transferase (alpha-GST). Concentration of pancreatitis-associated protein was measured to assess pancreatic integrity. Measurements were performed after induction of anesthesia, at the end of surgery, 4 hours after arrival in the intensive care unit, and on postoperative day 1. RESULTS The mean (+/- standard deviation) CPBT were 54 +/- 12 minutes and 99 +/- 16 minutes, respectively. PCO2gap increased significantly more in the group with CPBT of more than 80 minutes than in that with CPBT of less than 70 minutes, at +15 +/- 4 mm Hg versus +8 +/- 3 mm Hg, respectively, indicating reduction in splanchnic perfusion by longer CPBTs. Postoperative MEGX concentrations were significantly lower and postoperative alpha-GST concentrations were significantly higher in the group with CPBT of more than 80 minutes than in that with CPBT of less than 70 minutes. Plasma levels of pancreatitis-associated protein remained similar in both groups throughout the study period. CONCLUSIONS In our patients with CPBT of more than 80 minutes, splanchnic perfusion and hepatocelluar integrity were moderately affected, whereas pancreatic function remained almost unchanged. Studies including a larger patient population are necessary to assess whether protective approaches would be helpful in patients undergoing complex cardiac surgery with very long CPBT.

Renal Integrity in Sevoflurane Sedation in the Intensive Care Unit with the Anesthetic-Conserving Device: A Comparison with Intravenous Propofol Sedation

BACKGROUND: Increased inorganic fluoride levels after methoxyflurane exposure in the 1970s and prolonged intraoperative sevoflurane use have been suggested to be potentially nephrotoxic. In the intensive care unit we evaluated the effect on renal integrity of short-term inhaled postoperative sedation with sevoflurane using the Anesthetic Conserving Device (ACD) compared with propofol. METHODS: In this prospective, randomized, single-blinded study, after major abdominal, vascular or thoracic surgery 125 patients were allocated to receive either sevoflurane (n = 64) via the ACD (end-tidal 0.5–1 vol%) or IV propofol (n = 61) for postoperative sedation up to 24 h. Urinary &agr;-glutathione-s-transferase as primary outcome variable, urinary N-acetyl-glucosaminidase, serum creatinine, and inorganic fluoride concentrations, urine output and fluid management were measured preoperatively, at the end of surgery, and at 24 and 48 h postoperatively. RESULTS: The sedation time in the intensive care unit was comparable between the sevoflurane (9.2 ± 4.3 h) and the propofol (9.3 ± 4.7 h) group. Alpha-glutathione-s-transferase levels were significantly increased at 24 and 48 h postoperatively compared with preoperative values in both groups, without significant differences between the groups. N-acetyl-glucosaminidase and serum creatinine remained unchanged in both study groups, and urine output and creatinine clearance were comparable between the groups throughout the study period. Inorganic fluoride levels increased significantly (P < 0.001) at 24 h after sevoflurane exposure (39 ± 25 &mgr;mol/L) compared with propofol (3 ± 6 &mgr;mol/L) and remained elevated 48 h later (33 ± 26 vs 3 ± 5 &mgr;mol/L). One patient in each group suffered from renal insufficiency, requiring intensive diuretic therapy, but not dialysis, during hospital stay. CONCLUSIONS: Short-term sedation with either sevoflurane using ACD or propofol did not negatively affect renal function postoperatively. Although inorganic fluoride levels were elevated after sevoflurane exposure, glomerular and tubular renal integrity were preserved throughout the hospital stay.

Bispectral index in patients with target-controlled or manually-controlled infusion of propofol

UNLABELLED In this prospective, randomized study we compared bispectral index (BIS), hemodynamics, time to extubation, and the costs of target-controlled infusion (TCI) and manually-controlled infusion (MCI) of propofol. Forty patients undergoing first-time implantation of a cardioverter-defibrillator were included. Anesthesia was performed with remifentanil (0.2-0.3 micro g. kg(-1). min(-1)) and propofol. Propofol was used as TCI (plasma target concentration, 2.5-3.5 micro g/mL; n = 20) or MCI (3.0-4.0 mg. kg(-1). h(-1); n = 20). BIS, heart rate, and arterial blood pressure were measured at six data points: T1, before anesthesia; T2, after intubation; T3, after skin incision; T4, after first defibrillation; T5, after third defibrillation; and T6, after extubation. There were no significant hemodynamic differences between the two groups. BIS was significantly lower at T3 and T4 in the TCI group than in the MCI group. The mean dose of propofol was larger in TCI patients (5.8 +/- 1.4 mg. kg(-1). h(-1)) than in the MCI patients (3.7 +/- 0.6 mg. kg(-1). h(-1)) (P < 0.05), whereas doses of remifentanil did not differ. Time to extubation did not differ between the two groups (TCI, 13.7 +/- 5.3 min; MCI, 12.3 +/- 3.5 min). One patient in the MCI group had signs of intraoperative awareness without explicit memory after first defibrillation (BIS before shock, 49; after shock, 83). Costs were significantly less in the MCI group (34.83 US dollars) than in the TCI group (39.73 US dollars). BIS failed to predict the adequacy of anesthesia for the next painful stimulus. IMPLICATIONS In this prospective, randomized study, bispectral index (BIS), hemodynamics, time to extubation, and costs of target-controlled infusion (TCI) and manually-controlled infusion of propofol were compared. TCI increased the amount of propofol used. BIS failed to predict the adequacy of anesthesia for the next painful stimulus.