A randomized, double-blind, controlled study evaluating the effects of two facial serums on skin aging.

BACKGROUND: Skin aging is a natural process that occurs because of oxidative stress. Facial skin aging is often concerning for individuals due to the exposure of the face. OBJECTIVES: To assess and compare the effects of two anti-aging facial serums on the following characteristics associated with facial skin aging: fine lines/wrinkles, age spots, firmness, elasticity, texture, radiance, tone, lifting, clarity, and complexion. METHODS: A 24-week, double-blind controlled study was conducted on 130 participants who were randomized into two groups: facial serum with Liposomal Blend and facial serum without Liposomal Blend. Clinical evaluations (Visual Analog Scale) and instrumental evaluations (Cutometer, SIAscope, and Clarity Pro image analysis) were performed at weeks 0 (baseline), 2, 4, 8, 12, and 24 to assess for changes in skin aging characteristics. RESULTS: A total of 123 participants completed the study; participants that used the facial serum with Liposomal Blend had significantly greater improvements in skin aging characteristics compared to those that used the facial serum without Liposomal Blend. This study shows that Liposomal Blend is a vehicle with the ability to enhance the anti-aging properties of the ingredients within the facial serum by facilitating its delivery into the underlying layers of the skin. Higher concentration of ingredients at the site of action could potentially lead to greater damage repair and improvements in signs of facial skin aging. CONCLUSION: By using Liposomal Blend, practitioners and pharmacists could potentially improve the delivery of the ingredients within their formulations into the skin, which may lead to increased treatment efficacy.

Zeaxanthin-based dietary supplement and topical serum improve hydration and reduce wrinkle count in female subjects.

BACKGROUND: Dietary modification, through supplementation and elimination diets, has become an area of interest to help slow skin aging, reduce symptom severity or prevent reoccurrence of certain dermatologic conditions [Clinical Dermatology vol. 31 (2013) 677-700]. Free radical components (reactive oxygen species or ROS) or lipid peroxide (LPO) is involved in the pathogenesis and progression of accelerated skin aging when prolonged oxidative stress occurs. The use of antioxidant-related therapies such as nutraceuticals is of particular interest in restoring skin homeostasis. Antioxidant carotenoid zeaxanthin is concentrated in the eye and skin tissue and believed to decrease the formation of ROS associated with UV light exposure. With zeaxanthin, phytoceramides, and botanical extracts an oral and topical test product (with zeaxanthin, algae extracts, peptides, hyaluronate) have been developed to improve the appearance and condition of skin when used as directed. METHODS: Subjects were divided into three groups: two tests (skin formula 1 - oral product alone (ZO-1), skin formula 2- oral product with topical product (ZO-2 + ZT)), and one placebo control. The study consisted of a washout visit, baseline (randomization), week two (2), week four (4), week six (6), week eight (8), and week twelve (12). Key parameters measured were as follows: fine lines, deep lines, total wrinkles, wrinkle severity, radiance/skin color (L, a*, b*), discolorations, and skin pigment homogeneity. RESULTS: Thirty-one subjects completed the twelve-week study; no adverse events were recorded during the study. Statistically significant improvements from baseline mean hydration score were observed in active groups at weeks 2, 6, and 8. A statistically significant difference was observed between mean differences from baseline scores for total wrinkle count at week 4 for the combination active groups compared to placebo. A statistically significant difference from baseline scores for fine lines count was also observed at the week 4 visit compared to placebo for both active groups. Statistically significant differences from baseline scores for average wrinkles severity were seen for week 12 visit for both active groups compared to placebo. CONCLUSION: We have shown that the combination of zeaxanthin-based dietary supplement plus a topical formulation produces superior hydration to that of placebo. Additionally, we have shown that the combination of oral and topical combination vs. oral alone has superior abilities to improve parameters associated with facial lines and wrinkles compared to placebo, although the dietary supplement alone proved most effective in reducing wrinkle count and severity.

General anesthesia and methylenetetrahydrofolate reductase deficiency.

Methylenetetrahydrofolate reductase (MTHFR) deficiency is an autosomal recessive disorder with a spectrum of manifestations including neurological symptoms, premature arteriosclerosis, and venous and arterial thrombosis. Most patients are heterozygous for multiple MTHFR substitutions; small minorities are homozygous for mutations at this locus. Among these mutations, the C677T polymorphism is the most deleterious. Nitrous oxide use in anesthesia leads to significant increases in plasma homocysteine. We present a patient undergoing urgent surgery with a preoperative diagnosis of homozygous MTHFR deficiency.

The role of endogenous kallikrein inhibition in perioperative transfusion and adverse outcome in cardiac surgical patients.

OBJECTIVE: The goal of this study was to explore the relationship among endogenous plasma kallikrein inhibition (KI), perioperative bleeding, and adverse outcomes in cardiac surgery. DESIGN: A prospective, observational study. SETTING: University teaching hospitals. PARTICIPANTS: Cardiac surgical patients. INTERVENTIONS: Endogenous plasma KI levels (%) and kallikrein-like activity (KKA) were measured preoperatively, 30 minutes into cardiopulmonary bypass, and at the end of surgery. Patients were divided into quartiles of preoperative KI. Data including risk factors, blood loss, transfusion requirements, and postoperative outcomes were collected. MEASUREMENTS AND MAIN RESULTS: Preoperative endogenous KI ranged from 40% to 175%, where 100% represents the activity of pooled healthy volunteer plasma. The quartiles of KI levels were as follows: quartile 1, KI = 40% to 83.8% (n = 40); quartile 2, KI = 84% to 101.5% (n = 40); quartile 3, KI = 102% to 120% (n = 42); and quartile 4, KI = 121% to 175% (n = 38). The hematocrits on admission to the intensive care unit were as follows: quartile 1, 28% +/- 4%; quartile 2, 26% +/- 4%; quartile 3, 26% +/- 4%; and quartile 4, 24% +/- 4% (p = 0.009). Blood product use was similar among quartiles in the operating room. Quartiles 3 and 4 received more blood (p = 0.003) and platelet (p = 0.04) transfusions than quartiles 1 and 2 in the first 24 hours after surgery. More patients in quartile 4 were ventilated for more than 24 hours after surgery (p < 0.05). Hospital length of stay was longest in quartile 4 (p = 0.002). CONCLUSION: Contrary to expectation, higher endogenous KI levels were associated with more blood product transfusion, longer postoperative mechanical ventilation, and hospital length of stay. These findings raise questions as to the role of KI in postoperative outcomes.

Dexmedetomidine infusion is associated with enhanced renal function after thoracic surgery.

STUDY OBJECTIVE: To test the hypothesis that dexmedetomidine, a selective alpha-2 agonist, enhances urine flow rate and perioperative renal function, a post hoc analysis was conducted on a recently completed study of dexmedetomidine used as an adjunct to epidural analgesia after thoracotomy. DESIGN: Post hoc analysis of a randomized, placebo-controlled, double-blind clinical trial. SETTING: Tertiary-care university medical center. PATIENTS: 28 patients undergoing elective thoracotomy. INTERVENTIONS: Patients were prospectively randomized to receive a supplemental 24-hour intravenous infusion of either dexmedetomidine (0.4 microg kg(-1) h(-1), n = 14) or saline placebo (equivalent infusion rate, n = 14). MEASUREMENTS: Available renal parameters including urine output, calculated creatinine clearance (cCl(Cr)), daily serum creatinine level (S(Cr)), and the fractional change in S(Cr) level (DeltaS(Cr)%, [peak postoperative S(Cr) - baseline S(Cr)] / baseline S(Cr)) x 100) were recorded. MAIN RESULTS: Values are expressed as means +/- SD. There were no significant differences in baseline values between the groups. The dexmedetomidine group had significantly greater cumulative urine output at postoperative hour 4 (473 +/- 35 vs 290 +/- 122 mL, P = 0.001) and 12 (1033 +/- 240 vs 822 +/- 234 mL, P = 0.02), although only 14% of the group received diuretic agents, compared with 43% in the control group. The dexmedetomidine group had significantly better preserved perioperative renal function compared with the control group, as assessed by DeltaS(Cr)% (0.04% decrease vs 21% increase, P = 0.0007) and cCl(Cr) (75.3 +/- 13.2 vs 62.5 +/- 15.5 mL/min, P = 0.02). CONCLUSION: Dexmedetomidine infusion administered as a supplement to epidural analgesia induced diuresis in postthoracotomy patients with normal preoperative renal function and undergoing fluid restriction. Although this finding may represent simple reversal of a tubular antidiuresis, the lower DeltaS(Cr)% and preservation of cCl(Cr) suggest a beneficial effect on glomerular filtration compared with controls.

The association between duration of storage of transfused red blood cells and morbidity and mortality after reoperative cardiac surgery.

Red blood cells (RBCs) undergo numerous changes during storage; however, the clinical relevance of these storage "lesions" is unclear. We hypothesized that the duration of storage of transfused RBCs is associated with mortality after repeat sternotomy for cardiac surgery, because these patients are at high risk for both RBC transfusion and adverse outcome. We retrospectively analyzed 434 patients who underwent repeat median sternotomy for coronary artery bypass graft or valve surgery and who received allogeneic RBCs. Three-hundred-twenty-one (74%) patients met the criteria for eligibility. After adjusting for the effects of confounders and the total number of RBC transfusions, the duration of storage of the oldest RBC unit transfused was found to be associated with both in-hospital mortality (Cox proportional hazard ratio (HR) = 1.151; P < 0.0001) and out-of-hospital mortality (HR = 1.116; P < 0.0001). The mean duration of storage of transfused RBCs was also an independent predictor of in-hospital mortality (HR = 1.036; P < 0.0001). Independent associations between the duration of storage of transfused RBCs and acute renal dysfunction and intensive care unit and hospital length of stay were also observed. The duration of storage of RBCs is associated with adverse outcome after repeat sternotomy for cardiac surgery. The clinical significance of this finding should be investigated in a large, randomized, blinded clinical trial.

A randomized, double-blind, placebo-controlled study assessing the anti-inflammatory effects of ketamine in cardiac surgical patients.

OBJECTIVE: To determine whether ketamine administration affects markers of inflammation in cardiac surgery with cardiopulmonary bypass (CPB) and to investigate differences between 2 low-dose ketamine regimens. DESIGN: Prospective, randomized, placebo-controlled trial. SETTING: Single-center university hospital. PARTICIPANTS: Patients undergoing cardiac surgery with CPB. INTERVENTION: Patients (n = 50) were randomized to 1 of 3 groups: ketamine, 0.25 mg/kg (n = 15); ketamine, 0.5 mg/kg (n = 18);or placebo (n = 17) in a double-blind manner at the time of induction of general anesthesia. MEASUREMENTS AND MAIN RESULTS: Serum C-reactive protein (CRP) and interleukin (IL)-6, IL-8, and IL-10 were measured at baseline, on intensive care unit (ICU) arrival, and on the first postoperative day (POD 1). Both ketamine doses decreased the serum IL-6 response at ICU arrival and POD 1 compared with placebo (p < 0.05). CRP was lower in the 0.5-mg/kg group than placebo on POD 1 (p = 0.003). IL-10 was lower in the ketamine groups (p = 0.01) at POD 1 compared with placebo; IL-8 levels were not affected by ketamine. Mean arterial pressure and systemic vascular resistance were higher at the end of surgery, arrival in the ICU, and POD 1 in the ketamine groups (p < 0.05). CONCLUSION: Low-dose ketamine (0.5 mg/kg) attenuates increases in CRP, IL-6, and IL-10 while decreasing vasodilatation after CPB.

A prospective, double-blind, randomized, placebo-controlled study of dexmedetomidine as an adjunct to epidural analgesia after thoracic surgery.

OBJECTIVE: The purpose of this study was to test the hypothesis that after thoracic surgery, the supplementation of a low-dose thoracic epidural (ED) bupivacaine (0.125%) infusion by intravenous (IV) dexmedetomidine decreases analgesic requirement without causing respiratory depression. The primary endpoint was the need for additional ED bupivacaine administered through patient-controlled epidural analgesia (PCEA). Secondary endpoints included the requirement for supplemental opioids and the impact of dexmedetomidine on CO2 retention. DESIGN: A prospective, randomized, double-blinded study. SETTING: A major US tertiary care university hospital. PATIENTS: Twenty-eight patients scheduled to undergo elective thoracotomy for wedge resection, lobectomy, or pneumonectomy. INTERVENTIONS: On intensive care unit arrival, the thoracic ED catheter was loaded with 0.125% bupivacaine to a T4 sensory level and a continuous infusion of 0.125% bupivacaine without opioid was commenced at 4 mL/h. Patients were then randomized into 1 of 2 groups. The dexmedetomidine group received an IV loading dose of dexmedetomidine of 0.5 microg/kg over 20 minutes, followed by continuous IV infusion at 0.4 microg/kg/h. The placebo group received IV saline at the same calculated loading and infusion rates by volume. If necessary, supplemental analgesia (increased ED rate, ED fentanyl, ketorolac [IV]) was provided to ensure a visual analog scale (VAS) score of < or =3. MEASUREMENTS: The analgesic effect was monitored by the VAS, and the requirement for PCEA dosing and additional analgesics was recorded. Heart rate, blood pressure, and blood gases were also monitored. MAIN RESULTS: There was no significant difference in PCEA use and VAS score between the 2 groups, but requirement for supplemental ED fentanyl analgesia was significantly greater in the placebo group (66.1 +/- 95.6 v 5.3 +/- 17.1 microg, p = 0.039). Mean PaCO2 was also significantly greater in the placebo group (40.3 +/- 4.1 v 43.9 +/- 4.3 mmHg, p = 0.04). Patients in the dexmedetomidine group exhibited significantly decreased heart rate (1 patient required and responded to atropine) and blood pressure (4 patients required and readily responded to IV fluid) compared with the placebo group. CONCLUSION: The authors conclude that in postthoracotomy patients, IV dexmedetomidine is a potentially effective analgesic adjunct to thoracic ED bupivacaine infusion and may decrease the requirement for opioids and potential for respiratory depression.

Low-dose endotoxin elicits variability in the inflammatory response in healthy volunteers.

Endotoxin has been implicated as a cause of sepsis, inflammation and organ dysfunction after surgery. Patients differ in their response to endotoxin, and this may account for differences in outcome. The traditional human model of endotoxin challenge (2-4 ng/kg) is not associated with significant inter-individual variability in systemic inflammation and may not be suitable for studying variability in the inflammatory response. We examined whether low-dose regimens of endotoxin cause significant variability in inflammation. Volunteers (n = 30) were randomised in a double-blinded ('double-dummy') study to one of 6 dosing regimens: saline (placebo) or Escherichia coli O:113 endotoxin as a 4 ng/kg bolus (positive control), 0.25 ng/kg (bolus), 0.25 ng/kg (30 min infusion), 0.75 ng/kg (bolus) or 0.75 ng/kg (30 min infusion). Temperature, white cell count, platelet count, C-reactive protein and cytokine changes from baseline were measured. In contrast to subjects receiving placebo, those randomised to 4 ng/kg endotoxin exhibited significant systemic inflammation during the 10-h observation period. The four low-dose regimens elicited variability in most markers of inflammation. We conclude that low-dose endotoxin elicits inter-individual variability in inflammation and could be used to test factors that may affect the human response to endotoxin.

Thromboelastography maximum amplitude predicts postoperative thrombotic complications including myocardial infarction.

Postoperative thrombotic complications increase hospital length of stay and health care costs. Given the potential for thrombotic complications to result from hypercoagulable states, we sought to determine whether postoperative blood analysis using thromboelastography could predict the occurrence of thrombotic complications, including myocardial infarction (MI). We prospectively enrolled 240 patients undergoing a wide variety of surgical procedures. A cardiac risk score was assigned to each patient using the established revised Goldman risk index. Thromboelastography was performed immediately after surgery and maximum amplitude (MA), representing clot strength, was determined. Postoperative thrombotic complications requiring confirmation by a diagnostic test were assessed by a blinded observer. Ten patients (4.2%) suffered a total of 12 postoperative thrombotic complications. The incidence of thrombotic complications with increased MA (8 of 95 = 8.4%) was significantly (P = 0.0157) more frequent than that of patients with MA < or =68 (2 of 145 = 1.4%). Furthermore, the percentage suffering postoperative MI in the increased MA group (6 of 95 = 6.3%) was significantly larger than that in the MA < or =68 group (0 of 145 = 0%) (P = 0.0035). In a multivariate analysis, increased MA (P = 0.013; odds ratio, 1.16; 95% confidence interval, 1.03-1.20) and Goldman risk score (P = 0.046; odds ratio, 2.39; 95% confidence interval, 1.02-5.61) both independently predicted postoperative MI. A postoperative hypercoagulable state as determined by thromboelastography is associated with postoperative thrombotic complications, including MI, in a diverse group of surgical patients.

National survey regarding the management of an intraoperatively diagnosed patent foramen ovale during coronary artery bypass graft surgery.

OBJECTIVE: With the increased use of intraoperative transesophageal echocardiography (TEE), patent foramen ovale (PFO) has become a common finding during routine coronary artery bypass graft (CABG) surgery. This survey was designed to study potential differences in the management of intraoperatively diagnosed PFO. DESIGN: A written survey. SETTING: US university and community hospitals. PARTICIPANTS: The authors randomly selected 50% of US cardiac surgeons listed in the Cardiothoracic Surgery Network Database (n = 734). INTERVENTIONS: A written survey was mailed to the participants. The survey questions included respondents' use of TEE during CABG surgery, examination for a PFO with TEE, and management of intraoperatively diagnosed PFO in the CABG surgery. MEASUREMENTS AND MAIN RESULTS: Overall, 64% of individuals (468/734) responded to the survey request. TEE is available in the primary institution of 98.6% of respondents and used to search for a PFO in approximately one third of all CABG surgeries. During planned on-pump CABG surgery, 27.9% of respondents always close an intraoperatively diagnosed PFO, whereas 10.2% of respondents never close an intraoperatively diagnosed PFO. During planned off-pump CABG surgery, 27.6% of surgeons never change their plan, and 11% of respondents always convert the procedure to on-pump CABG to close the PFO. The majority of respondents decide whether to close a PFO based on the size of the PFO, the right atrial pressure, and a history of possible paradoxical embolism. CONCLUSIONS: In the United States, TEE is used extensively during CABG surgery. There is significant variability in how intraoperatively diagnosed PFO is managed during CABG surgery.

A randomized, double-blind comparison of lactated Ringer's solution and 0.9% NaCl during renal transplantation.

Normal saline (NS; 0.9% NaCl) is administered during kidney transplantation to avoid the risk of hyperkalemia associated with potassium-containing fluids. Recent evidence suggests that NS may be associated with adverse effects that are not seen with balanced-salt fluids, e.g., lactated Ringer's solution (LR). We hypothesized that NS is detrimental to renal function in kidney transplant recipients. Adults undergoing kidney transplantation were enrolled in a prospective, randomized, double-blind clinical trial of NS versus LR for intraoperative IV fluid therapy. The primary outcome measure was creatinine concentration on postoperative Day 3. The study was terminated for safety reasons after interim analysis of data from 51 patients. Forty-eight patients underwent living donor kidney transplants, and three patients underwent cadaveric donor transplants. Twenty-six patients received NS, and 25 patients received LR. There was no difference between groups in the primary outcome measure. Five (19%) patients in the NS group versus zero (0%) patients in the LR group had potassium concentrations >6 mEq/L and were treated for hyperkalemia (P = 0.05). Eight (31%) patients in the NS group versus zero (0%) patients in the LR group were treated for metabolic acidosis (P = 0.004). NS did not adversely affect renal function. LR was associated with less hyperkalemia and acidosis compared with NS. LR may be a safe choice for IV fluid therapy in patients undergoing kidney transplantation.

Abnormal gastric tonometric variables and vasoconstrictor use after left ventricular assist device insertion.

BACKGROUND: Abnormal gastric tonometric variables, a surrogate for splanchnic ischemia, occur in approximately 50% of patients at the end of routine cardiac operations and are associated with postoperative morbidity. We sought to determine whether gastric tonometric variables deteriorate after left ventricular assist device insertion and to explore the association between abnormal gastric tonometric variables and vasoconstrictor use. METHODS: Nineteen patients who had insertion of a left ventricular assist device were enrolled in a prospective, observational study. Automated air tonometry was used to determine the difference between gastric and arterial partial pressure of carbon dioxide (CO2 gap) at five time points perioperatively. RESULTS: Compared with baseline, systemic blood flow was significantly increased at the end of operation (1.9 +/- 0.6 versus 2.9 +/- 0.7 L x min(-1) x m(-2), p < 0.0001). Tonometric variables, which were normal at baseline, became abnormal in 90% of patients (baseline CO2 gap 4 +/- 2 mm Hg versus end of operation CO2 gap 24 +/- 15 mm Hg, p < 0.0001). Elevated CO2 gaps correlated with larger doses of norepinephrine (r = 0.69, p = 0.001) and vasopressin (r = 0.88, p < 0.0001). Abnormal gastric tonometric variables at the end of operation correlated with postoperative intensive care unit length of stay (r = 0.70, p = 0.0009) and multiple organ dysfunction score (r = 0.64, p = 0.0033). CONCLUSIONS: Despite a significant increase in systemic blood flow after left ventricular assist device implantation, abnormal gastric tonometric variables developed and were associated with larger vasoconstrictor dose. These data provide evidence that gastric ischemia can develop independently of changes in systemic blood flow and support the potential role of vasoconstrictors as a cause of splanchnic ischemia.

Gastric hypercarbia and adverse outcome after cardiac surgery.

OBJECTIVE: It has been postulated that splanchnic ischemia, as manifested by gastric hypercarbia, helps to trigger excessive systemic inflammation, which has been linked to the development of adverse postoperative outcome. This study examined whether gastric PCO(2) values are associated with adverse outcome in cardiac surgical patients. DESIGN AND SETTING: Prospective cohort study in a tertiary-care hospital. PATIENTS: 43 patients undergoing elective cardiac surgery. INTERVENTIONS: Simultaneous measurements of gastric PCO(2) (using automated air tonometry) and arterial PCO(2) were obtained at the beginning and end of surgery. The difference (gap) between regional PCO(2) and arterial PCO(2) (corrected for temperature) was calculated. Adverse outcome was defined as in-hospital death or prolonged (>10 days) postoperative hospitalization. MEASUREMENTS AND RESULTS: Fourteen patients fulfilled the predefined definition for adverse outcome. Postoperative ICU stay and postoperative hospital length of stay were significantly longer in these patients. At the end of surgery gastric minus arterial PCO(2) gap was significantly larger in patients with adverse outcome. Global hemodynamic and perfusion related variables were not associated with adverse outcome (cardiac index, mean arterial pressure, mixed venous oxygen saturation, arterial lactate, arterial base excess). CONCLUSIONS: Gastric minus arterial PCO(2) gap after surgery is larger in patients with adverse postoperative outcome, which supports the theory that gastrointestinal reduced perfusion is relevant to the pathogenesis of postoperative morbidity.

Stroke after cardiac surgery: a retrospective analysis of the effect of aprotinin dosing regimens.

BACKGROUND: Half-dose aprotinin (HDA) appears to be equivalent to full-dose aprotinin (FDA) in its ability to prevent bleeding. However, data regarding the potential effect of aprotinin use and dosage on other outcomes such as the occurrence of perioperative stroke are limited. It has been postulated that the higher level of kallikrein inhibition obtained with FDA dosing may be required for end-organ protection. Therefore, we performed a retrospective study in cardiac surgery patients at high risk for developing stroke to determine the relative effects of FDA and HDA regimens on the incidence of postoperative stroke. METHODS: Records of 1,524 patients undergoing cardiac surgery over a 15-month period were reviewed. Patients at high risk for stroke were selected if they met all of the following predefined criteria: age greater than 70 years, history of hypertension, history of diabetes mellitus, history of stroke or transient ischemic attack, and presence of aortic atheroma. A validated preoperative stroke risk index was calculated for each patient. Postoperative stroke required confirmation by computed tomography or magnetic resonance imaging. Patients were divided into three groups according to whether they were administered no aprotinin, HAD, or FDA. RESULTS: A total of 149 patients fulfilled the criteria for being at high risk for stroke. Stroke risk index was very similar (p = 0.56) in the three groups: those who received no aprotinin and served as a control group (124 +/- 15, n = 56), those who were given HDA (123 +/- 12, n = 67), and those who received FDA (122 +/- 11 n = 26). Preoperative and intraoperative characteristics were also similar between the three study groups. Overall, the incidence of stroke was 16% (24/149). The incidence of stroke differed (p < 0.05) among the three groups: no aprotinin 16% (9/56), HDA 22% (15/67), and FDA 0% (0/26). CONCLUSIONS: In this retrospective study of cardiac surgery patients at high risk for postoperative stroke, the administration of FDA but not HDA was associated with a lower incidence of stroke.

Differences in arterial and venous thromboelastography parameters: potential roles of shear stress and oxygen content.

OBJECTIVE: To investigate potential mechanisms for the differences in thromboelastography variables observed between arterial blood samples and venous blood samples. DESIGN: Prospective cohort study. SETTING: University hospital. PARTICIPANTS: Patients undergoing cardiac surgery (n = 33). INTERVENTIONS: After the withdrawal of 10 mL of discarded blood (>3 deadspace volumes), 3 blood samples were withdrawn simultaneously from the central venous port of the pulmonary artery catheter (CVP), the radial arterial catheter (ART), and the side port of the 9F sheath introducer (SI). MEASUREMENTS AND MAIN RESULTS: Thromboelastography was done simultaneously on each sample. All thromboelastography analyses were performed with 1% celite and heparinase according to the manufacturer's guidelines. A total of 80 ART, SI, and CVP comparisons were obtained. Mean hematocrit values were not different between sampling sites (27 +/- 4 v 27 +/- 4 v 27 +/- 3). Thromboelastography R time values (mean +/- SD) were CVP, 8 +/- 3; ART, 10 +/- 3; and SI, 13 +/- 5 (p = 0.004). Thromboelastography maximal amplitude (MA) values (mean +/- SD) were CVP, 60.4 +/- 11.7; ART, 56.2 +/- 11.4; and SI, 50.5 +/- 13.2 (p = 0.008). Calculated maximal shear stresses were CVP, 48 dyne/cm(2); ART, 36 dyne/cm(2); and SI, 0.3 dyne/cm(2). Blood samples obtained from the CVP (highest shear stress) resulted in faster (shorter R) and stronger (larger MA) coagulation compared with the arterial site (intermediate shear stress) and sheath introducer (lowest shear stress). CONCLUSION: These data show that differences exist in thromboelastography values between arterial and venous blood samples and, more importantly, show that the differences observed are not related to differences in oxygen content. These differences seem to be related to differences in catheter lumen diameter and, presumably, shear forces.

Preserved gastric tonometric variables in cardiac surgical patients administered intravenous perflubron emulsion.

UNLABELLED: Low gastric intramucosal pH (pHi) and an increased gastric-arterial PCO2 difference (CO2 gap) are markers of tissue hypoperfusion. Perfluorocarbons (PFCs) have a large oxygen-carrying capacity and release oxygen when encountering low tissue oxygen tension. Nine cardiac surgical patients instrumented for gastric tonometry were enrolled as part of a multicenter, randomized, single-blinded study of a PFC emulsion (perflubron emulsion [Oxygent]). Patients were randomized to receive PFC (n = 4) or placebo (n = 5) after intraoperative autologous blood harvesting by acute normovolemic hemodilution. At baseline there were no intergroup differences in tonometric-, hemodynamic-, or oxygen delivery-derived variables, e.g., Control group (pHi, 7.37 +/- 0.06; CO2 gap, 6.4 +/- 1.3 mm Hg) versus PFC group (pHi, 7.38 +/- 0.06; CO2 gap, 6.7 +/- 1.5 mm Hg). After acute normovolemic hemodilution, pHi was significantly lower (P < 0.01) in the Control group (7.22 +/- 0.25) than in the PFC group (7.44 +/- 0.25), and CO2 gap was significantly higher (P < 0.001) in the Control group (23.4 +/- 5.1 mm Hg) than in the PFC group (1.8 +/- 0.8 mm Hg). These differences in tonometric variables persisted during surgery. The PFC group showed a significantly (P < 0.007) shorter time to first bowel movement postoperatively (2.0 +/- 0.8 vs 5.4 +/- 1.6 days). Time to consumption of solid food was also shorter in the PFC group and almost achieved statistical significance (P = 0.056). IMPLICATIONS: This study suggests that the administration of perflubron emulsion prevents gastrointestinal tract ischemia in cardiac surgical patients and may preserve postoperative gastrointestinal tract function.