Plant essential oils synergize various pyrethroid insecticides and antagonize malathion in Aedes aegypti

Pyrethroid resistance is a significant threat to agricultural, urban and public health pest control activities. Because economic incentives for the production of novel active ingredients for the control of public health pests are lacking, this field is particularly affected by the potential failure of pyrethroid-based insecticides brought about by increasing pyrethroid resistance. As a result, innovative approaches are desperately needed to overcome insecticide resistance, particularly in mosquitoes that transmit deadly and debilitating pathogens. Numerous studies have demonstrated the potential of plant essential oils to enhance the efficacy of pyrethroids. The toxicity of pyrethroids combined with plant oils is significantly greater than the baseline toxicity of either oils or pyrethroids applied alone, which suggests there are synergistic interactions between components of these mixtures. The present study examined the potential of eight plant essential oils applied in one of two concentrations (1% and 5%) to enhance the toxicity of various pyrethroids (permethrin, natural pyrethrins, deltamethrin and β-cyfluthrin). The various plant essential oils enhanced the pyrethroids to differing degrees. The levels of enhancement provided by combinations of plant essential oils and pyrethroids in comparison with pyrethroids alone were calculated and synergistic outcomes characterized. Numerous plant essential oils significantly synergized a variety of pyrethroids; type I pyrethroids were synergized to a greater degree than type II pyrethroids. Eight plant essential oils significantly enhanced 24-h mortality rates provided by permethrin and six plant essential oils enhanced 24-h mortality rates obtained with natural pyrethrins. By contrast, only three plant essential plants significantly enhanced the toxicity of deltamethrin and β-cyfluthrin. Of the plant essential oils that enhanced the toxicity of these pyrethroids, some produced varying levels of synergism and antagonism. Geranium, patchouli and Texas cedarwood oils produced the highest levels of synergism, displaying co-toxicity factors of > 100 in some combinations. To assess the levels of enhancement and synergism of other classes of insecticide, malathion was also applied in combination with the plant oils. Significant antagonism was provided by a majority of the plant essential oils applied in combination with this insecticide, which suggests that plant essential oils may act to inhibit the oxidative activation processes within exposed adult mosquitoes.

Essential oils enhance the toxicity of permethrin against Aedes aegypti and Anopheles gambiae

Insecticide resistance and growing public concern over the safety and environmental impacts of some conventional insecticides have resulted in the need to discover alternative control tools. Naturally occurring botanically-based compounds are of increased interest to aid in the management of mosquitoes. Susceptible strains of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Anopheles gambiae (Meigen) (Diptera: Culicidae) were treated with permethrin, a common type-I synthetic pyrethroid, using a discriminate dose that resulted in less than 50% mortality. Piperonyl butoxide (PBO) and 35 essential oils were co-delivered with permethrin at two doses (2 and 10 µg) to determine if they could enhance the 1-h knockdown and the 24-h mortality of permethrin. Several of the tested essential oils enhanced the efficacy of permethrin equally and more effectively than piperonyl butoxide PBO, which is the commercial standard to synergize chemical insecticide like pyrethroids. PBO had a strikingly negative effect on the 1-h knockdown of permethrin against Ae. aegypti, which was not observed in An. gambiae. Botanical essential oils have the capability of increasing the efficacy of permethrin allowing for a natural alternative to classic chemical synergists, like PBO.

Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery

BACKGROUND

Improvement in patient outcome and reduced use of medical resources may result from using epidural anesthesia and analgesia as compared with general anesthesia and intravenous opioids, although the relative importance of intraoperative versus postoperative technique has not been studied. This prospective, double-masked, randomized clinical trial was designed to compare alternate combinations of intraoperative anesthesia and postoperative analgesia with respect to postoperative outcomes in patients undergoing surgery of the abdominal aorta.

METHODS

One hundred sixty-eight patients undergoing surgery of the abdominal aorta were randomly assigned to receive either thoracic epidural anesthesia combined with a light general anesthesia or general anesthesia alone intraoperatively and either intravenous or epidural patient-controlled analgesia postoperatively (four treatment groups). Patient-controlled analgesia was continued for at least 72 h. Protocols were used to standardize perioperative medical management and to preserve masking intraoperatively and postoperatively. A uniform surveillance strategy was used for the identification of prospectively defined postoperative complications. Outcome evaluation included postoperative hospital length of stay, direct medical costs, selected postoperative morbidities, and postoperative recovery milestones.

RESULTS

Length of stay and direct medical costs for patients surviving to discharge were similar among the four treatment groups. Postoperative outcomes were similar among the four treatment groups with respect to death, myocardial infarction, myocardial ischemia, reoperation, pneumonia, and renal failure. Epidural patient-controlled analgesia was associated with a significantly shorter time to extubation (P = 0.002). Times to intensive care unit discharge, ward admission, first bowel sounds, first flatus, tolerating clear liquids, tolerating regular diet, and independent ambulation were similar among the four treatment groups. Postoperative pain scores were also similar among the four treatment groups.

CONCLUSIONS

In patients undergoing surgery of the abdominal aorta, thoracic epidural anesthesia combined with a light general anesthesia and followed by either intravenous or epidural patient-controlled analgesia, offers no major advantage or disadvantage when compared with general anesthesia alone followed by either intravenous or epidural patient-controlled analgesia.

Mechanism of interference of a polymerized hemoglobin blood substitute in an alkaline phosphatase method

BACKGROUND

Hemoglobin-based oxygen carriers can cause profound interferences in many analytical procedures. We determined the mechanism of interference in the assay of alkaline phosphatase activity and identified approaches that might be used to correct for this interference.

METHODS

Interference of a polymerized hemoglobin blood substitute with the assay of alkaline phosphatase was examined with a Hitachi 917 analyzer and ultraviolet-visible spectrophotometry.

RESULTS

Hemoglobin-based oxygen carrier solutions had substantial absorbance at 415 nm, the wavelength of analysis used to measure the formation of 4-nitrophenol. In addition to offsetting the initial absorbance at the analytical wavelength, polymerized hemoglobin gave rise to a strong negative interference plot because of alkali denaturation of the substitute. The same interference mechanism was also observed for native hemoglobin (hemolysate), indicating that the interference was not derived from the polymerization process. The interference can be corrected by implementing a rate-correction procedure, or the interference can be avoided by measurement at 450 nm.

CONCLUSIONS

The interference of polymerized hemoglobin in the alkaline phosphatase assay is a result of an absorbance offset caused by alkali denaturation of hemoglobin. The interference can be corrected or avoided by modifying the calculation or the analytical wavelength. The correction strategy may also be applicable to improving the hemolysis index for this method.

The reduction of the allogenic transfusion requirement in aortic surgery with a hemoglobin-based solution

OBJECTIVE

Because of allogenic red blood cell (RBC) availability and infection problems, novel alternatives, including hemoglobin-based oxygen-carrying solutions (HBOC), are being explored to minimize the perioperative requirement of RBC transfusions. This study evaluated HBOC-201, a room-temperature stable, polymerized, bovine-HBOC, as a substitute for allogenic RBC transfusion in patients undergoing elective infrarenal aortic operations.

METHODS

In a single blind, multicenter trial, 72 patients were prospectively randomized two-to-one to HBOC (n = 48) or allogenic RBC (n = 24) at the time of the first transfusion decision, either during or after elective infrarenal aortic reconstruction. Patients randomized to the HBOC group received 60 g of HBOC for the initial transfusion and had the option to receive three more doses (30 g each) within 96 hours. In this group, any further blood requirement was met with allogenic RBCs. Patients randomized to the allogenic RBC group received only standard RBC transfusions. The efficacy analysis was a means of assessing the ability of HBOC to eliminate the requirement for any allogenic RBC transfusions from the time of randomization through 28 days. Safety was evaluated by means of standard clinical trial methods.

RESULTS

The two treatment groups were comparable for all baseline characteristics. Although all patients in the allogenic RBC group required at least one allogenic RBC transfusion, 13 of 48 patients (27%; 95% CI, 15% to 42%) in the HBOC group did not require any allogenic RBC transfusions. The only significant changes documented were a 15% increase in mean arterial pressure and a three-fold peak increase in serum urea nitrogen concentration after HBOC. The complications were similar in both groups, with no allergic reactions. There were two perioperative deaths (8%) in the allogenic RBC group and three perioperative deaths (6%) in the HBOC group (P = 1.0).

CONCLUSION

HBOC significantly eliminated the need for any allogenic RBC transfusion in 27% of patients undergoing infrarenal aortic reconstruction, but did not reduce the median allogenic RBC requirement. HBOC transfusion was well tolerated and did not influence morbidity or mortality rates.

Control of blood pressure and heart rate in patients randomized to epidural or general anesthesia for lower extremity vascular surgery. Perioperative Ischemia Randomized Anesthesia Trial (PIRAT) Study Group

STUDY OBJECTIVE

To examine the degree of success at maintaining patients randomized to epidural or general anesthesia for peripheral vascular surgery within predetermined blood pressure (BP) and heart rate (HR) limits. To investigate associations between such hemodynamic control and intraoperative myocardial ischemia and postoperative major cardiac morbidity.

DESIGN

Prospective randomized clinical trial.

SETTING

University-affiliated hospital.

PATIENTS

100 patients undergoing elective lower extremity revascularization for atherosclerotic peripheral vascular disease.

INTERVENTIONS

Patients were randomized to receive either epidural anesthesia or general anesthesia. Blood pressure and HR limits were determined prior to randomization. Hemodynamic monitoring and management of anesthesia was standardized. Myocardial ischemia and major cardiac morbidity were diagnosed by a blinded cardiologist, based on continuous ambulatory ECG monitoring, cardiac enzymes, and 12 lead ECGs. Intraoperative BP and HR date were analyzed by investigators masked to the type of anesthesia given.

MEASUREMENTS AND MAIN RESULTS

A greater percentage of patients randomized to general anesthesia had intraoperative BPs more above their limit (95% vs 72%, p = 0.002) and/or more rapid changes in HR (75% vs 48%, p = 0.008) or BP (100% vs 93%, p = 0.04) than those randomized to epidural anesthesia. Intraoperative ischemia and major cardiac morbidity were similar in the two anesthesia groups. Patients experiencing intraoperative ischemia, regardless of anesthetic type, more frequently had BPs greater than 10% above their upper limit (90% vs 60% p = 0.04) and/or more rapid HR changes (90% vs 58%, p = 0.03) compared with patients without ischemia. These vital sign abnormalities, however, were not necessarily temporally related to the ischemic episodes. Patients experiencing subsequent major cardiac morbidity were not different from other patients with respect to excursions out of BP on HR limits.

CONCLUSIONS

Prevention of elevated intraoperative BP and/on rapid changes in BP or HR may be more successful with epidural than with general anesthesia. Such vital sign abnormalities may occur more frequently in patients who have had intraoperative ischemia or are at risk for having it later in the procedure.

Catecholamine and cortisol responses to lower extremity revascularization: correlation with outcome variables. Perioperative Ischemia Randomized Anesthesia Trial Study Group

OBJECTIVE

To determine whether catecholamine and cortisol secretory responses to surgery contribute to postoperative complications.

DESIGN

Prospective, randomized, case series.

SETTING

A university hospital operating suite and surgical intensive care unit.

PATIENTS

Sixty patients undergoing lower extremity vascular surgery.

INTERVENTIONS

Patients were randomized to receive either epidural anesthesia/epidural opiate analgesia (regional anesthesia) or general anesthesia/intravenous patient-controlled analgesia (general anesthesia).

MEASUREMENTS AND MAIN RESULTS

Anesthesia was managed according to a prospectively designed protocol. Hemodynamic parameters and plasma catecholamine concentrations were determined at specific intraoperative and postoperative time points. Intraoperative and postoperative urine samples were collected and analyzed for free cortisol concentrations. Outcomes evaluated were cardiac (nonfatal myocardial infarction and cardiac death) and surgical (graft occlusion). Mean arterial pressure during emergence from anesthesia and in the early postoperative period correlated positively with plasma norepinephrine concentration (p < .01). In addition, plasma catecholamine concentrations were higher in patients with postoperative hypertension. Plasma norepinephrine concentrations at the time of emergence from anesthesia and postoperatively were also higher in patients requiring repeat surgery for graft revision, thrombectomy, or amputation (p < .05). Multivariate analysis indicated that the norepinephrine concentration at the time of emergence, but not type of anesthesia, correlated with reoperation for graft occlusion, suggesting that the previously reported beneficial effect of regional anesthesia may be due to modulation of the stress response. Myocardial infarction or cardiac death occurred in three patients. These patients had markedly increased catecholamine concentrations.

CONCLUSIONS

The catecholamine response to lower extremity vascular surgery contributes to the development of postoperative hypertension and may also be important in the development of thrombotic complications.

The influence of anesthetic method on infrainguinal bypass graft patency: a closer look

Although several studies have demonstrated a reduced incidence of postoperative deep venous thrombosis among patients who receive regional anesthesia, the influence of anesthetic method on early arterial bypass graft patency has not been well studied. The records of 78 consecutive patients undergoing elective femoro-popliteal (FP) or femoro-tibial (FT) bypass grafts, and who were randomized to receive general anesthesia and postoperative patient-controlled intravenous narcotic analgesia (GEN, n = 41), or epidural anesthesia and postoperative continuous epidural analgesia (EPI, n = 37), were retrospectively reviewed. The two groups were evenly matched with respect to demographic characteristics, risk factors, and vascular variables. There was one death in each group, yielding an operative mortality of 2.6 per cent, and leaving 76 patients available for further analysis. Graft occlusion occurred in 11 (14.5%) cases within the first 7 postoperative days, including 9 (22.5%) GEN and 2 (5.6%) EPI patients (P < 0.05). There were two (4.4%) FP occlusions, including two (8.7%) GEN and 0(0%) EPI cases; there were nine FT occlusions, including seven (41.2%) GEN and two (14.3%) EPI cases. Graft occlusion occurred in 11 (17.1%) of the 64 limb salvage cases, including nine (27.3%) GEN and two (6.5%) EPI cases (P < 0.05), and in seven (12.7%) of 55 greater saphenous vein grafts, including six (22.2%) GEN and 1 (3.6%) EPI cases (P < 0.05). By multivariate analysis, FT grafts, preoperative plasminogen activator inhibitor-1 (PAI-1) levels, and GEN were predictive of early graft occlusion (P < 0.05). Furthermore, the levels of circulating PAI-1 were higher 24 hours postoperatively among patients in the GEN group (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Determinants of catecholamine and cortisol responses to lower extremity revascularization. The PIRAT Study Group

BACKGROUND

Surgical trauma elicits diffuse changes in hormonal secretion and autonomic nervous system activity. Despite studies demonstrating modulation of the stress response by different anesthetic/analgesic regimens, little is known regarding the determinants of catecholamine and cortisol responses to surgery.

METHODS

Plasma catecholamines and cortisol secretion data were obtained from 60 patients undergoing lower extremity revascularization. Patients were randomized to receive either general anesthesia combined with patient-controlled intravenous morphine (GA) or epidural anesthesia combined with epidural fentanyl analgesia (RA). All aspects of intra- and postoperative clinical care were defined by written protocol. Plasma catecholamines were measured before induction, intraoperatively, and for the first 18 h postoperatively (by HPLC). Urine cortisol was measured intra- and postoperatively using RIA. Data were evaluated using univariate and multivariate analyses to evaluate demographic and perioperative variables as determinants of stress hormone secretion.

RESULTS

Plasma catecholamines increased during skin closure in the GA group, and remained higher relative to the RA group in the postoperative period. Multivariate analysis indicated that age and anesthetic regimen predicted increases in catecholamines during skin closure (P < 0.005), although duration of surgery, blood loss, and body temperature were not correlated. Early postoperative norepinephrine concentrations were correlated with pain score and duration of surgery (P < 0.004), but not with anesthetic management, blood loss, or body temperature. All postoperative norepinephrine levels were highly correlated (r = 0.7) with norepinephrine levels during skin closure. Cortisol excretion was higher postoperatively than intraoperatively. No patient or perioperative variable predicted cortisol excretion, and cortisol excretion was not correlated with catecholamine levels at any time.

CONCLUSIONS

These data indicate that patient factors, such as age and inherent sympathetic responsivity, are important determinants of the catecholamine response to surgery. Modulation of the norepinephrine response by regional anesthesia/analgesia appears to be related, in part, to superior analgesia. The lack of correlation between catecholamine and cortisol secretion indicates that the stress response may consist of discrete systems responding to different stimuli.

Perioperative morbidity in patients randomized to epidural or general anesthesia for lower extremity vascular surgery. Perioperative Ischemia Randomized Anesthesia Trial Study Group

BACKGROUND

Perioperative morbidity may be modifiable in high risk patients by the anesthesiologist's choice of either regional or general anesthesia. This clinical trial compared outcomes between epidural (EA) and general (GA) anesthesia/analgesia regimens in a group of patients at high risk for cardiac and other morbidity who were undergoing similarly stressful surgical procedures.

METHODS

One hundred patients scheduled for elective vascular reconstruction of the lower extremities were randomized to receive either EA for surgery followed by epidural analgesia, or GA for surgery followed by intravenous patient-controlled analgesia. Hemodynamic monitoring, blood pressure, and heart rate limits were determined prior to randomization. Management of anesthesia in the immediate postoperative period was standardized. The data collected included continuous electrocardiographic monitoring from the day before surgery through the third postoperative day, serial electrocardiograms, and cardiac enzymes. Cardiac ischemia, myocardial infarction, unstable angina, and cardiac death were identified by a cardiologist blinded to the type of anesthesia received. Other major morbidity was determined at the time of hospital discharge and at 1 and 6 months after surgery.

RESULTS

Eleven patients who received GA required regrafting or an embolectomy during their hospital stay, compared with two patients who received EA. This association of GA with reoperation remained significant after adjustment for baseline differences. Cardiac outcomes were similar in the two groups with respect to perioperative death (1 EA and 1 GA), death within 6 months (4 EA and 3 GA), nonfatal myocardial infarction within 7 days (2 EA and 2 GA), unstable angina (0 EA and 2 GA), and myocardial ischemia following randomization (17 EA and 23 GA). Rates of major infections in the two groups (1 EA and 2 GA), renal failure (3 EA and 3 GA), and pulmonary complications (3 EA and 7 GA) also were similar.

CONCLUSIONS

Carefully conducted epidural and general anesthesia appear to be associated with comparable rates of cardiac and most other morbidity in patients undergoing lower extremity vascular surgery. However, compared with general anesthesia, epidural anesthesia is associated with a lower incidence of reoperation for inadequate tissue perfusion and, therefore, may be advantageous for this surgical population.

The effects of different anesthetic regimens on fibrinolysis and the development of postoperative arterial thrombosis. Perioperative Ischemia Randomized Anesthesia Trial Study Group

BACKGROUND

The purpose of this clinical trial was to compare the effects of different anesthetic and analgesic regimens on hemostatic function and postoperative arterial thrombotic complications.

METHODS

Ninety-five patients scheduled for elective lower extremity vascular reconstruction were randomized to receive either epidural anesthesia followed by epidural fentanyl (RA) or general anesthesia followed by intravenous morphine (GA). Intraoperative and postoperative care were controlled by protocol using predetermined limits for heart rate, blood pressure, and other monitoring criteria. Data collection included serial physical examinations, electrocardiograms, and cardiac isoenzymes to detect arterial thrombosis (defined as unstable angina, myocardial infarction, or vascular graft occlusion requiring reoperation). Fibrinogen, plasminogen activator inhibitor-1 (PAI-1), and D-dimer levels were measured preoperatively and at 24 and 72 h postoperatively.

RESULTS

Preoperative fibrinogen levels were similar in both groups, remained unchanged after 24 h, and increased equally (45%) in the first 72 h postoperatively. PAI-1 levels in the GA group increased from 13.6 +/- 2.1 activity units (AU)/ml to 20.2 +/- 2.6 AU/ml at 24 h and returned to baseline at 72 h. In contrast, PAI-1 levels in the RA group remained unchanged over time. Twenty-two of 95 patients (23%) had postoperative arterial thrombosis, 17 of whom had received GA and 5 of whom, RA. Preoperative PAI-1 levels were higher in patients who developed postoperative arterial thrombosis (20.5 +/- 3.6 AU/ml vs. 11.2 +/- 1.4 AU/ml). Multiple logistic regression analysis indicated that GA and preoperative PAI-1 levels were predictive of postoperative arterial thrombotic complications.

CONCLUSIONS

Impaired fibrinolysis may be related causally to postoperative arterial thrombosis. Because RA combined with epidural fentanyl analgesia appears to prevent postoperative inhibition of fibrinolysis, this form of perioperative management may decrease the risk of arterial thrombotic complications in patients undergoing lower extremity revascularization.

Unintentional hypothermia is associated with postoperative myocardial ischemia. The Perioperative Ischemia Randomized Anesthesia Trial Study Group

BACKGROUND

Hypothermia occurs commonly during surgery and can be associated with increased metabolic demands during rewarming in the postoperative period. Although cardiac complications remain the leading cause of morbidity after anesthesia and surgery, the relationship between unintentional hypothermia and myocardial ischemia during the perioperative period has not been studied.

METHODS

One hundred patients undergoing lower extremity vascular reconstruction received continuous Holter monitoring throughout the first 24 h postoperatively. Myocardial ischemia was determined by a cardiologist masked to clinical variables. The patient's sublingual temperature on arrival at the intensive care unit immediately after the surgical procedure was used to divide the patients into two groups: hypothermic (temperature, < 35 degrees C; n = 33) and normothermic (temperature, > or = 35 degrees C; n = 67). The relationship between intentional hypothermia and myocardial ischemia occurring during the first postoperative day was evaluated by univariate and multivariate analyses.

RESULTS

A greater percentage of patients had electrocardiographic changes consistent with myocardial ischemia in the hypothermic group (36%, 12 of 33) compared with those in the normothermic group (13%, 9 of 67, P = 0.008). Preoperative risk factors for perioperative cardiac morbidity were similar between the two groups, except for patient age. The mean age was 70 +/- 2 yr and 62 +/- 1 yr in the hypothermic and normothermic groups, respectively (P = 0.001). When subgroup and multivariate analyses were used to adjust for differences in age, temperature remained an independent predictor of ischemia (odds ratio, 1.82 per degree Celsius; 95% confidence interval, 1.09-3.02). The incidence of postoperative angina was greater in the hypothermic group (18%, 6 of 33) than in the normothermic group (1.5%, 1 of 67, P = 0.002). The incidence of PaO2 < 80 mmHg in the arterial blood was greater in the hypothermic group (52%, 17 of 33) than in the normothermic group (30%, 20 of 67, P = 0.03).

CONCLUSIONS

Unintentional hypothermia is associated with myocardial ischemia, angina, and PaO2 < 80 mmHg during the early postoperative period in patients undergoing lower extremity vascular surgery.

Breath ethane: a specific indicator of free-radical-mediated lipid peroxidation following reperfusion of the ischemic liver

A major component of the organ injury mediated by toxic oxidants, such as seen following reperfusion of the ischemic liver, is due to the peroxidation of polyunsaturated fatty acids, especially of cell membranes. We utilized the measurement of exhaled breath ethane, a metabolic product unique to oxidant-mediated lipid peroxidation, as a noninvasive indicator of this process in swine liver subjected to warm ischemia/reperfusion. Under rigorously controlled anesthesia conditions, pig livers were subjected to 2 h of warm total ischemia, followed by reperfusion in situ. Expired air was collected and its ethane content quantitated by a novel gas chromatographic technique. The time course of breath ethane generation correlated closely with the appearance of hepatocellular injury as measured by impairment of Factor VII generation and other measures of liver integrity. Moreover, the administration of the specific superoxide free radical scavenger, superoxide dismutase (SOD), significantly attenuated both the elaboration of ethane and the hepatocellular injury. These findings not only provide confirmation of the previously reported link between hepatocellular injury by free radicals generated at reperfusion, but also establish the use of expired breath ethane analysis as a sensitive, specific, and noninvasive indicator of the injury process in real time.

Epidural versus general anesthesia, ambient operating room temperature, and patient age as predictors of inadvertent hypothermia

To elucidate the multifactorial nature of perioperative changes in body temperature, the influence of several clinical variables, including anesthetic technique, ambient operating room temperature, and age, were evaluated. Perioperative oral sublingual temperatures were measured in 97 patients undergoing lower extremity vascular surgery randomized to receive either general (GA) or epidural (EA) anesthesia. Surgery and anesthesia were performed in operating rooms (OR) with a relatively warm mean ambient temperature (24.5 +/- 0.4 degrees C) (GA, n = 30; EA, n = 33) or relatively cold mean ambient temperature (21.3 +/- 0.3 degrees C) (GA, n = 21; EA, n = 13). Patients were 35-94 yr old, with a mean age of 64.5 +/- 1.1 yr. A regression analysis was performed to determine the variables that correlated with intraoperative decrease in temperature and postoperative rewarming rate. The major correlates of greater intraoperative decrease in temperature were 1) GA (P = 0.003); 2) cold ambient OR temperature (P = 0.07); and 3) advancing patient age (P = 0.03). There was significant interaction between ambient OR temperature and type of anesthesia (P = 0.03): there was a greater intraoperative decrease in temperature with GA compared to EA in a cold OR but a similar decrease with GA and EA in a warm OR. The data also suggest an interaction between type of anesthesia and patient age (P = 0.06), showing a greater decrease in temperature with GA compared to EA in the younger patients, but a similar decrease between GA and EA in older patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Right- and left-arm blood pressure discrepancies in vascular surgery patients

To identify a relationship between atherosclerotic vascular disease and differences in blood pressure between the right and left arms, blood pressure differences between arms were measured in patients with peripheral vascular disease (PVD, n = 58), in patients with coronary artery disease (CAD, n = 38), and in patients with no evidence of atherosclerotic disease, who served as a control group (n = 38). The incidence and magnitude of right and left arm pressure difference determined by the oscillometric technique were compared between the patient groups. The incidence of systolic pressure difference greater than or equal to 20 mmHg between arms in patients with PVD (21%) was greater than that in either those with CAD (3%) (P less than or equal to 0.05) or control subjects (0%) (P less than 0.01). The incidence of systolic pressure difference greater than or equal to 45 mmHg between arms in patients with PVD (10%) was greater than that in either those with CAD (0%) (P less than 0.05) or control subjects (0%) (P less than 0.05). Patients with PVD also had a greater incidence of right and left arm difference than did those with CAD or controls for mean and diastolic blood pressures. Of all patients with a systolic difference greater than 10 mmHg, neither the right nor the left arm blood pressure was consistently higher: 21 of 35 (60%) had a higher pressure in the right arm, and 14 of 35 (40%) had a higher pressure in the left arm (P = 0.33). Gender, diabetes, hypertension, smoking, and age were not associated with a difference in blood pressure between the right and left arms.(ABSTRACT TRUNCATED AT 250 WORDS)