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Biomedical subjects

S M Frank

Publications and source records attributed to S M Frank.

At least 37 records · Page 2Linked to original sources
PubMed1997

Changes in cerebrospinal fluid pressure and lactate concentrations during thoracoabdominal aortic aneurysm surgery.

BACKGROUND: Although ischemic injury to the spinal cord is a well-known complication of aortic surgery, no metabolic markers have been identified as predictors of an adverse outcome. This study evaluated the effect of cerebrospinal fluid (CSF) drainage, with and without distal femoral perfusion or moderate hypothermia on blood and CSF lactate concentrations and CSF pressure during thoracoabdominal aortic aneurysm surgery. METHODS: Three nonconcurrent groups of patients were studied prospectively: patients with normal body temperature (35 degrees C) but without distal femoral bypass (n = 6), patients with normal body temperature with bypass (n = 7), and patients with hypothermia (30 degrees C) and bypass (n = 8). In all patients, CSF pressure was recorded before, during, and after aortic cross-clamping. During the surgical repair, CSF drainage was performed using a 4-Fr intrathecal silicone catheter. Blood and CSF lactate concentrations were measured throughout the operation. RESULTS: Significant increases in blood (490%) and CSF (173%) lactate concentrations were observed during and after thoracic aortic occlusion in patients with normothermia and no bypass (P < 0.02 and 0.05, respectively). Distal perfusion attenuated the increase in both blood and CSF lactate (P < 0.01), and a further reduction was achieved with hypothermia of 30 degrees C (P < 0.001). Patients who became paraplegic showed a greater increase in CSF lactate concentrations after aortic clamp release compared with those who suffered no neurological damage (275% vs. 123% of baseline; P < 0.05). Increased CSF pressure of 42-60% (P < 0.005) was noted soon after thoracic aortic occlusion, both with and without distal femoral bypass. CONCLUSIONS: Incremental reductions in CSF lactate concentrations were achieved using distal femoral bypass and hypothermia. The reduction in CSF lactate correlated with the methods used to protect the spinal cord during thoracoabdominal aortic aneurysm surgery and was associated with better outcome. Decompression by distal bypass of the hemodynamic overload caused by aortic occlusion was insufficient to eliminate the acute increase in CSF pressure. Cerebrospinal fluid lactate measurements during high aortic surgery may accurately represent the spinal cord metabolic balance.

Adult↗
PubMed1997

Adrenergic, respiratory, and cardiovascular effects of core cooling in humans.

The adrenergic, respiratory, and cardiovascular responses to isolated core cooling were assessed in awake human subjects. Mild core hypothermia was induced by intravenous infusion of 30 or 40 ml/kg of cold saline (4 degrees C) on 2 separate days. A warm intravenous infusion (30 ml/kg, 37 degrees C) was given on a third day as a control treatment. Mean norepinephrine concentration increased 400% and total body oxygen consumption increased 30% when core temperature decreased 0.7 degrees C. Mean norepinephrine concentration increased 700% and total body oxygen consumption increased 112% when core temperature decreased 1.3 degrees C. Core cooling was associated with peripheral vasoconstriction and increased mean arterial blood pressure, whereas heart rate was unchanged. Plasma epinephrine and cortisol concentrations were unchanged during core cooling. There were no changes in any measured parameter with the warm infusion. These findings suggest that mild hypothermia induced by isolated core cooling is associated with an adrenergic response characterized by peripheral sympathetic nervous system activation without a significant adrenocortical or adrenomedullary response. The respiratory and cardiovascular responses to core cooling are characterized by a shivering-induced increase in metabolic rate, norepinephrine-mediated peripheral vasoconstriction, and increased arterial blood pressure.

Adolescent↗
PubMed1996

Single doses of intravenous protamine result in the formation of protamine-specific IgE and IgG antibodies.

BACKGROUND: Protamine reactions are a well-recognized and serious complication of intravenous protamine administration. IgE-mediated anaphylaxis occurs after initial sensitization and subsequent re-exposure to antigens. Subcutaneous protamine in insulin preparations is associated with protamine-specific IgE and IgG antibody production. In contrast, the influence of intravenous protamine administration on protamine-specific IgE and IgG antibody formation has never been investigated. METHODS: Sera from 93 patients were analyzed for protamine-specific IgE and IgG antibodies both before and 4 to 6 weeks after exposure to single doses of intravenous protamine. Specific clinical variables were assessed by univariate and multivariate analyses to determine independent predictors of protamine-specific antibody production. RESULTS: In patients who were previously seronegative, intravenous protamine administration resulted in protamine-specific IgE and IgG antibody production in 17 of 93 (18%) and 15 of 93 (16%) patients, respectively. As determined by multivariate analysis, male gender (p = 0.06) and insulin-dependent diabetes mellitus (p = 0.002) were associated with protamine-specific IgG but not IgE antibody production. CONCLUSION: Single-dose intravenous protamine resulted in protamine-specific IgE and/or IgG antibody production in 26 of 93 (28%) of patients. Seroconversion was associated with male gender and insulin-dependent diabetes mellitus. Patients responding immunologically to protamine may be at increased risk for experiencing reactions on subsequent exposure.

Aged↗
PubMed1996

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.

Aged↗
PubMed1996

Thermoregulation and heart rate variability.

1. Heart rate variability is modulated by multiple control systems, including autonomic and hormonal systems. Long-term variability, i.e. the very low-frequency band of the power spectra, has been postulated to reflect thermoregulatory vasomotor control, based upon thermal entrainment experiments. However, the relationship between thermoregulatory responses (vasoconstriction and shivering) and heart rate variability has not been studied. 2. We performed two distinct protocols in a series of human subjects. In the first protocol, core temperature was reduced by intravenous infusion of cold saline, while skin temperature was unchanged. The second protocol involved skin-surface warming and cooling until shivering developed. Power spectral analysis was performed using a fast Fourier transformation, and the area in three distinct band-widths was determined. 3. Very low-frequency power (0.0039-0.04 Hz) increased significantly in response to core cooling, peripheral vasoconstriction and shivering, while both very low- and low- (0.04-0.15 Hz) frequency power increased in response to skin-surface cooling. Heart rate decreased during core cooling-induced vasoconstriction, suggesting a direct thermal response, and increased in relation to the metabolic demands associated with shivering. 4. Our results suggest that very low-frequency power is modulated by thermal stimuli which result in core hypothermia and thermoregulatory activity, while skin-surface cooling without core hypothermia does not selectively modulate this frequency band.

Adult↗
PubMed1996

alpha-Adrenoceptor mechanisms of thermoregulation during cold challenge in humans.

1. Previous studies on the thermoregulatory effects of alpha-adrenoceptor antagonists have been performed primarily in animals and the findings have been inconsistent. There is evidence for thermoregulatory impairment by alpha-adrenergic antagonists in humans not exposed to cold, but the effects of alpha-adrenergic blockade during cold challenge have not been investigated. 2. Fourteen healthy human volunteers (seven elderly, aged 55-68 years and seven young, aged 19-27 years) were studied on three separate days and received three randomly assigned treatments; (i) control (no drug), (ii) low-dose phentolamine and (iii) high-dose phentolamine. On each day cold intravenous saline (4 degrees C) was given until both vasoconstriction and shivering were triggered or a maximum fluid volume (40 ml/kg) was delivered. Core temperature, peripheral vasoconstriction and metabolic heat production were measured. 3. The alpha-adrenoceptor antagonist caused a dose-dependent inhibition of vasoconstriction in the elderly but did not impair vasoconstriction in the young subjects at the doses that were given. Shivering and metabolic heat production were unaffected by alpha-adrenergic blockade in the elderly or in the young. 4. These findings illustrate the selective inhibition of vasoconstriction (but not shivering) by alpha-adrenoceptor antagonism in elderly individuals. Compared with the young, the elderly are more sensitive to the effects of alpha-antagonists, perhaps due to downregulation of the alpha-adrenoceptor. These findings lead us to conclude that thermoregulatory vasoconstriction is alpha-adrenergically mediated, and this response is attenuated by alpha-adrenoceptor blockade in elderly humans.

Adrenergic alpha-Antagonists↗
PubMed1995

Intraoperative blood loss during radical retropubic prostatectomy: epidural versus general anesthesia.

OBJECTIVES: There are conflicting reports on the influence of different anesthetic techniques, such as regional versus general anesthesia, on intraoperative blood loss. The purpose of this study was to elucidate the effects of anesthetic technique on intraoperative blood loss in men undergoing radical retropubic prostatectomy (RRP). METHODS: One hundred patients undergoing RRP for prostate cancer were randomly assigned to receive either epidural anesthesia (EA), combined epidural and general anesthesia (EG), or general anesthesia alone (GA). Intraoperative blood loss was calculated by using a formula that accounted for the volume and hematocrit of the fluid suctioned from the surgical field, blood absorbed on surgical pads, and the patient's hematocrit. RESULTS: Mean blood loss in the EA group (1490 +/- 90 mL; mean +/- SEM) was significantly less than mean blood loss in both the EG group (1810 +/- 100 mL) and the GA group (1940 +/- 130 mL) (P = 0.01). Blood loss was not different between the EG and the GA groups (P = 0.7). Significantly less blood was transfused during surgery in the EA group (730 +/- 50 mL) compared with the EG (960 +/- 60 mL) and GA (950 +/- 70 mL) groups (P = 0.02). CONCLUSIONS: Similar blood loss in patients receiving general anesthesia, either alone or when combined with epidural anesthesia, implies that epidural anesthesia did not reduce bleeding, but, rather, that general anesthesia increased blood loss.

Anesthesia, Epidural↗
PubMed1995

Role of alpha-adrenoceptors in the maintenance of core temperature in humans.

1. Although alpha-adrenoceptor antagonists have been shown to induce core hypothermia in animals, it is unclear whether the primary mechanism is increased heat loss or decreased heat production. Furthermore, studies have not been performed in humans to determine the role of alpha-adrenoceptors in the maintenance of core temperature. 2. alpha-Adrenoceptor blockade was achieved with three doses of phentolamine given by random assignment on three different study days in five male and five female healthy subjects. Core temperature, mean skin-surface temperature, fingertip capillary blood flow and metabolic heat production were measured. Dose-response curves were plotted for all measured variables, and males and females were compared to identify potential gender differences. 3. Core temperature decreased with all doses of phentolamine. At the completion of the phentolamine infusion, the decrease in core temperature was more significant with high-dose (0.3 +/- 0.1 degrees C, P = 0.03) and with medium-dose (0.2 +/- 0.0 degrees C, P = 0.05) phentolamine than with low-dose phentolamine (0.1 +/- 0.0 degrees C). The maximum core temperature decrease during the study was more significant with high dose (0.6 +/- 1 degrees C) than with medium (0.3 +/- 1 degrees C, P = 0.04) or low (0.3 +/- 1 degrees C, P = 0.005) doses. Mean skin-surface temperature was increased with all doses. Fingertip blood flow was increased (approximately 60% above baseline) with the medium and high doses, but was unchanged with the low dose. Total body oxygen consumption was unchanged regardless of dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1995

The catecholamine, cortisol, and hemodynamic responses to mild perioperative hypothermia. A randomized clinical trial.

BACKGROUND: Unintended hypothermia occurs frequently during surgery and may have adverse effects on the cardiovascular system. Although the mechanisms responsible for the cardiovascular manifestations of hypothermia are unclear, it is possible that they are sympathetically mediated. In this prospective study, relationships between body temperature, the neuroendocrine response, and hemodynamic changes in the perioperative period were examined. METHODS: Seventy-four elderly patients, undergoing abdominal, thoracic, or lower extremity vascular surgical procedures, were randomly assigned to either "routine care" (n = 37) or "forced-air warming" (n = 37) groups. Throughout the intraoperative and early postoperative periods, the routine care group received standard thermal care, and the forced-air warming group received forced-air skin-surface warming. Core temperature, forearm minus fingertip skin-surface temperature gradient, and plasma concentrations of epinephrine, norepinephrine, and cortisol were measured throughout the perioperative period, and the two groups were compared. In addition, heart rate and arterial blood pressure were compared between groups. RESULTS: The routine care and forced-air warming groups did not differ with regard to age, sex, type of surgical procedures, anesthetic techniques, or postoperative analgesia. Mean core temperature was lower in the routine care group on admission to the postanesthetic care unit (routine care, 35.3 +/- 0.1 degree C; forced-air warming, 36.7 +/- 0.1 degree C; P = 0.0001) and remained lower during the early postoperative period. Forearm minus fingertip skin-surface temperature gradient (an index of peripheral vasoconstriction) was greater in the routine care group in the early postoperative period. The mean norepinephrine concentration (pcg/ml) was greater in the routine care group immediately after surgery (480 +/- 70 vs. 330 +/- 30, P = 0.02) and at 60 min (530 +/- 50 vs. 340 +/- 30, P = 0.002) and 180 min (500 +/- 80 vs. 320 +/- 30, P = 0.004) postoperatively. Mean epinephrine concentrations were not significantly different between groups. Mean cortisol concentrations were increased in both groups during the early postoperative period (P < 0.01), but the differences between groups were not significant. Systolic, mean, and diastolic arterial blood pressures were significantly higher in the routine care group. CONCLUSIONS: Compared with patients in the forced-air warming group, patients receiving routine thermal care had lower core temperatures, a greater degree of peripheral vasoconstriction, higher norepinephrine concentrations, and higher arterial blood pressures in the early postoperative period. These findings suggest a possible mechanism for hypothermia-related cardiovascular morbidity in the perioperative period.

Aged↗
PubMed1995

Multivariate determinants of early postoperative oxygen consumption in elderly patients. Effects of shivering, body temperature, and gender.

BACKGROUND: Previous investigators have proposed that postoperative shivering may be poorly tolerated by patients with cardiopulmonary disease because of the associated significant increase in total-body oxygen consumption. However, the often-quoted 300-400% increase in oxygen consumption with shivering was derived from relatively few studies performed in a small number of younger persons specifically selected on the basis of clinically recognizable shivering. We hypothesized that the average elderly postoperative patient has a shivering response that is associated with a relatively small increase in total-body oxygen consumption. METHODS: One hundred eleven elderly patients (age > 60 yr) undergoing surgery were studied to assess the determinants of shivering and total-body oxygen consumption in the early postoperative period. Anesthetic technique, postoperative analgesia, and thermal management were controlled by protocol. The clinical variables associated with shivering and increased total-body oxygen consumption were determined by univariate and multivariate analyses. RESULTS: Mean total-body oxygen consumption in shivering patients was 38% greater than in nonshivering patients. Regardless of whether data from shivering patients were included in the analysis, oxygen consumption was directly proportional to mean body temperature. Despite similar core temperatures, men had a greater incidence of clinically recognizable shivering and greater total-body oxygen consumption than did women. CONCLUSIONS: The metabolic demands associated with postoperative shivering in elderly patients are less than those reported previously in younger persons. These findings suggest that if hypothermia predisposes to cardiovascular complications in the postoperative period, these complications are not likely to be mediated by shivering and increased metabolism.

Aged↗
PubMed1995

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.

Adult↗
PubMed1995

Forced-air warming versus routine thermal care and core temperature measurement sites.

Hypothermia occurs commonly during the perioperative period and is preventable with proper warming measures and body temperature monitoring. Using a prospective, randomized study design, we compared forced-air warming (Warm Touch, Mallinckrodt Medical, Inc, St Louis, MO) (n = 15) with routine thermal care (n = 14) during the intraoperative and early postoperative periods. The results show that compared with routine thermal care, forced-air warming resulted in higher core temperatures both intraoperatively and postoperatively. The incidence of shivering was lower and thermal comfort scores were higher in the warming group. A secondary focus in this study was to assess the correlation between body temperatures measured at the urinary bladder, oral cavity, rectum, and tympanic membrane. The results indicated that the sites most highly correlated with tympanic temperature (listed in order of most to least correlated) were the bladder, rectum, and oral cavity. Assuming tympanic temperature is most representative of "core" temperature, oral measurements were likely to underestimate core temperature, whereas bladder and rectal temperatures overestimated core temperature. The relationship between body temperatures measured at commonly used monitoring sites must be recognized by nurses to account for the tendency to overestimate or underestimate core temperature. This knowledge can be applied in the management of patients in the operating room or PACU and specifically in the evaluation of PACU patients before discharge.

Aged↗
PubMed1994

Reflex cutaneous vasoconstriction during cold pressor test is mediated through alpha-adrenoceptors.

The effects of the cold pressor test on the coronary circulation have been clearly defined but the effects on the peripheral vasculature are less well understood. To measure the peripheral vasomotor response during cold pressor test perfusion in the upper extremity contralateral to the cold immersion was assessed by laser Doppler flowmetry and skin-surface temperature gradients. To identify the mechanism of vasoconstriction, cold pressor test was performed before and after the administration of phentolamine, an alpha-adrenoceptor antagonist. Vasoconstriction during cold pressor test was demonstrated by both skin-surface temperature gradients and by laser Doppler flowmetry. This vasoconstrictor response was significantly attenuated by the administration of phentolamine. The results demonstrate that the cold pressor test induces an alpha-adrenoceptor mediated vasoconstriction in the peripheral vasculature.

Adult↗
PubMed1994

A new percutaneous technique for establishing venous bypass access in orthotopic liver transplantation.

Partial veno-venous bypass (VVB) is commonly used in orthotopic liver transplantation (OLT). Venous access for blood return during VVB classically uses a surgical cutdown on the left axillary vein (LAV), which may prolong operating time and can be associated with significant complications. The authors have developed an alternative means of establishing venous access whereby the anesthesia team places 8.5F venous cannulae preoperatively in one or two vessels (internal jugular, antecubital, or subclavian) percutaneously using the Seldinger technique. These cannulae then serve to accept venous return from below the diaphragm via a centrifugal pump. The aim fo the present study was to compare the hemodynamic profiles obtained during the anhepatic phase of OLT in patients in whom either a conventional LAV catheter (group 1) or percutaneous catheters (group 2) were used for return flow from a centrifugal pump. There were no identifiable complications related to venous access in either group of patients. Total operating room time was 800 +/- 30 minutes in group 1 and 720 +/- 40 minutes in group 2 (P = 0.17). Hemodynamic parameters were determined from continuous strip chart recordings of arterial, right atrial, and inferior vena caval (IVCP) pressures. Cardiac output (CO) was measured by thermodilution whereas pump flow was determined by an electromagnetic probe. Renal perfusion pressure (RPP) was calculated as the difference between mean arterial pressure (MAP) and IVCP. Bypass pump flow was greater, but not significantly different between group 1 (3.0 +/- 0.2 L/min) and group 2 (2.4 +/- 0.2 L/min) (P = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Axillary Vein↗
PubMed1994

Postoperative morbidity is similar in patients anesthetized with epidural and general anesthesia for radical prostatectomy.

OBJECTIVES: To compare the effect of epidural and general anesthesia on the postoperative course and complication rate in patients undergoing radical prostatectomy. METHODS: Ninety-eight men scheduled for radical retropubic prostatectomy (RRP) were randomly assigned to receive epidural anesthesia only (EA, n = 34), combined epidural and general anesthesia (EG, n = 33) or general anesthesia only (GA, n = 31). In the EA group, epidural anesthesia was induced and maintained with bupivacaine. In the EG group, patients received epidural bupivacaine after the induction of general anesthesia. In the GA group, anesthesia was induced with morphine and maintained with isoflurane. In the postoperative period, epidural patient-controlled analgesia (PCA) was maintained in all patients for 3 to 5 days. Patients were evaluated throughout the hospitalization period and at 3, 6, and 12 weeks following surgery. RESULTS: The three groups did not differ with regard to postoperative pain, bleeding, urine output, fever, length of paralytic ileus, or length of hospitalization. No major cardiovascular, pulmonary, or neurologic complications occurred in any of the patients either perioperatively or in the first 3 months postoperatively. CONCLUSIONS: Intraoperative anesthetic technique was not associated with a different postoperative complication rate in patients undergoing RRP. The very low incidence of complications and the uniform postoperative analgesic regimen may have contributed to the similarity between groups.

Analgesia, Patient-Controlled↗
PubMed1994

Moderate hypothermia, with partial bypass and segmental sequential repair for thoracoabdominal aortic aneurysm.

PURPOSE: Ischemic injury to the spinal cord, kidneys, and viscera occurs in a significant number of patients undergoing surgical repair of thoracoabdominal aortic aneurysms. Partial bypass has been used to perfuse the arterial system distal to the cross-clamp, but the primary determinant of ischemic morbidity remains the duration of aortic cross-clamping. Hypothermia may favorably affect outcome during these procedures, but moderate or deep hypothermia has traditionally required full cardiopulmonary bypass with cardiac arrest. METHODS: In a series of patients undergoing thoracoabdominal (n = 14) or thoracic (n = 4) aneurysm repair, we used moderate hypothermia (30 degrees C) and partial bypass (aortofemoral or atriofemoral) while maintaining an intrinsic cardiac rhythm. Body temperature was controlled with a heat exchanger in the bypass circuit, which allowed for rapid cooling and rewarming. In addition to hypothermia and bypass, a segmental sequential surgical repair was used to minimize the duration of ischemia to any given vascular bed. RESULTS: All patients survived the surgical procedure, and 16 patients survived until discharge from the hospital. None of the 18 patients had paraplegia or significant renal dysfunction. The only complication related to hypothermia was atrial fibrillation, which occurred in three patients and was amenable to therapeutic measures. CONCLUSIONS: We conclude that moderate hypothermia, partial bypass, and segmental sequential repair may reduce ischemic injury. This combination of adjuncts was not associated with significant complications in this series of patients.

Aged↗
PubMed1994

The effect of epidural versus general anesthesia on postoperative pain and analgesic requirements in patients undergoing radical prostatectomy.

BACKGROUND: Although preemptive analgesia has been shown to decrease postinjury pain in animals, studies in humans have provided controversial results. The authors studied whether surgical epidural anesthesia with local anesthetics could affect postoperative pain and analgesic demands, when compared with general anesthesia. METHODS: Male patients scheduled for radical retropubic prostatectomy were randomly assigned to receive epidural anesthesia only (EA, n = 34), combined epidural and general anesthesia (EG, n = 32), or general anesthesia only (GA, n = 30). A lumbar epidural catheter was inserted and tested in all patients. In the EA group, an induction dose of 0.25 ml/kg epidural bupivacaine (0.5%) was followed during surgery by a continuous infusion of 0.1 ml.kg-1.h-1 0.125% bupivacaine. In the EG group, 0.2 ml/kg epidural bupivacaine (0.5%) was injected after induction of general anesthesia but before surgery, followed by epidural infusion of 0.1 ml.kg-1.h-1 0.125% bupivacaine. In the GA group, anesthesia was maintained with morphine, isoflurane, and N2O. Epidural patient-controlled analgesia (PCA) was provided with bupivacaine and fentanyl for all patients in the postoperative period. Postoperative pain scores and analgesic requirements were examined and compared between groups every 4-8 h for 3-5 postoperative days. RESULTS: Intraoperatively, EA patients received significantly more epidural bupivacaine than EG patients (129 +/- 6 mg vs. 98 +/- 6 mg, respectively. Recovery room median residual sensory level in EA patients (T6 +/- 2) was significantly higher than in EG patients (T10 +/- 2). PCA demand was greater in the GA and EG groups when compared with the EA group in postoperative days 2 (126 +/- 9 ml, 112 +/- 9 ml, 90 +/- 6 ml, respectively; P = 0.01) and 3 (89 +/- 10 ml, 83 +/- 9 ml, 48 +/- 5 respectively; P = 0.005). There was no difference in PCA demand between the GA and EG groups in the postoperative period. No significant clinical differences in postoperative mean pain scores were recorded in the first 5 days after surgery in the three anesthetic groups (range 0-2/10). CONCLUSIONS: In patients undergoing lower abdominal surgery, the neuraxial blockade and surgical anesthesia achieved by epidural local anesthetics was associated with decreased postoperative analgesic demands. Lower postoperative analgesic requirements in the EA group, when compared with both the EG and GA groups, indicate that: (1) EA patients had less postoperative pain, and (2) an efficient intraoperative blockade of noxious afferent signals to the central nervous system is fundamental in reducing postoperative pain.

Analgesia, Patient-Controlled↗