The blocking effect of epidural analgesia on the adrenocortical and hyperglycemic responses to surgery

Indoleamine-2,3-Dioxygenase as a Perioperative Marker of the Immune System

Indoleamine-2,3-dioxygenase (IDO) is the “rate-limiting” enzyme in the kynurenine (Kyn) pathway of the tryptophan (Trp) catabolism. By its immune-modulatory effect, IDO initiates changes to the physiologically balanced immune state and plays a key role in the pathogenesis of various diseases, as well as in the perioperative setting during surgery. In autoimmune processes, highly malignant cancers such as glioblastoma or organ transplantation, IDO’s involvement has been studied extensively. However, in severe systemic infections, as present in sepsis, it is not yet completely understood. Hereafter, in this narrative review, we present the current knowledge of IDO’s implication on such complex immune-related processes. Moreover, we address the role of IDO as a predictive biomarker as well as a therapeutic target for immune-mediated diseases. Finally, we discuss IDO in the setting of surgical trauma-induced stress and highlight its promising use as a biomarker in the pre-operative setting for all disciplines involved in the decision-making process and treatment of patients undergoing surgery.

The influence of anesthesia type on perioperative maternal glycemic-stress response during elective cesarean section: A prospective cohort study

BACKGROUND

It has been known that the type of anesthesia can affect the stress response to surgery in form of hyperglycemia. This study aims to evaluate and compare the influence of general anesthesia (GA) and spinal anesthesia (SA) on pregnant women who are scheduled to undergo cesarean section (CS) and to understand the impact of obstetrical factors on the maternal hyperglycemic-stress response during CS.

METHODS

Prospectively, we identified, assessed and followed those pregnant women who were scheduled to undergo elective CS surgery. The included group comprises any women who was scheduled to undergo an elective CS. The preoperative and postoperative blood glucose levels were measured and compared between both groups (GA and SA groups).

RESULTS

The study included 302 patients who satisfied the inclusion and exclusion criteria of the study. GA was more commonly utilized in cesarean sections (56.6%) compared with SA (43.4%). The average gestational age at time of delivery was 37.4 weeks. The post-operative readings were significantly higher in the GA group with a mean sugar level of 110.1 mg/dL and a mean sugar level in the SA group of 87.7 mg/dL (P = 0.00). After performing multiple regression analysis, it was revealed that the type of anesthesia is the most independent factor affecting the postoperative sugar level.

CONCLUSION

GA causes higher blood glucose concentrations than SA, which indicates that the impact of GA on hormonal stress response and metabolic hemostasis is greater than in SA.

Impact of Adrenal Function on Hemostasis/Endothelial Function in Patients Undergoing Surgery

Context

Glucocorticoids regulate hemostatic and endothelial function, and they are critical for adaptive functions during surgery. No data regarding the impact of adrenal function on hemostasis and endothelial function in the perioperative setting are available.

Objective

We assessed the association of adrenal response to adrenocorticotropic hormone (ACTH) and markers of endothelial/hemostatic function in surgical patients.

Methods

This prospective observational study, conducted at a tertiary care hospital, included 60 patients (35 male/25 female) undergoing abdominal surgery. Adrenal function was evaluated by low-dose ACTH stimulation test on the day before, during, and the day after surgery. According to their stimulated cortisol level (cutoff ≥ 500 nmol/L), patients were classified as having normal hypothalamic-pituitary-adrenal (HPA)-axis function (nHPA) or deficient HPA-axis function (dHPA). Parameters of endothelial function (soluble vascular cell adhesion molecule-1, thrombomodulin) and hemostasis (fibrinogen, von Willebrand factor antigen, factor VIII [FVIII]) were measured during surgery.

Results

Twenty-one patients had dHPA and 39 had nHPA. Compared with nHPA, patients with dHPA had significantly lower peak cortisol before (median 568 vs 425 nmol/L, P < 0.001) and during (693 vs 544 nmol/L, P < 0.001) surgery and lower postoperative hemoglobin levels (116 g/L vs 105 g/L, P = 0.049). FVIII was significantly reduced in patients with dHPA in uni- and multivariable analyses; other factors displayed no significant differences. Coagulation factors/endothelial markers changed progressively in relation to stimulated cortisol levels and showed a turning point at cortisol levels between 500 and 600 nmol/L.

Conclusions

Patients with dHPA undergoing abdominal surgery demonstrate impaired hemostasis which can translate into excessive blood loss.

Article Commentary: Defining New Directions for More Effective Management of Surgical Pain in the United States: Highlights of the Inaugural Surgical Pain Congress™

Despite advances in pharmacologic options for the management of surgical pain, there appears to have been little or no overall improvement over the last two decades in the level of pain experienced by patients. The importance of adequate and effective surgical pain management, however, is clear, because inadequate pain control 1) has a wide range of undesirable physiologic and immunologic effects; 2) is associated with poor surgical outcomes; 3) has increased probability of readmission; and 4) adversely affects the overall cost of care as well as patient satisfaction. There is a clear unmet need for a national surgical pain management consensus task force to raise awareness and develop best practice guidelines for improving surgical pain management, patient safety, patient satisfaction, rapid postsurgical recovery, and health economic outcomes. To comprehensively address this need, the multidisciplinary Surgical Pain Congress™ has been established. The inaugural meeting of this Congress (March 8 to 10, 2013, Celebration, Florida) evaluated the current surgical pain management paradigm and identified key components of best practices.

Effect of Spinal Anesthesia versus General Anesthesia on Blood Glucose Concentration in Patients Undergoing Elective Cesarean Section Surgery: A Prospective Comparative Study

Background

This prospective study compared the blood glucose concentration with spinal anesthesia or general anesthesia in patients undergoing elective cesarean section surgery.

Methods

In total, 58 pregnant women who underwent elective cesarean section surgery were included in this prospective comparative study. Group S (n = 35) included patients who chose spinal anesthesia, and group G (n = 23) included patients who chose general anesthesia. The patients were allocated to the groups upon patients' preference. For the group G, the blood glucose concentration (BGC) was obtained 5 minutes before induction, T1, and 5 minutes after induction T2. For the group S, the BGC was obtained immediately before the injection of the local anesthetic agent T1 and 5 minutes after the complete block T2. For both groups, BGC was measured 5 minutes before the end of surgery T3 and 30 minutes after the end of surgery T4. For BGC measurements, we used a blood glucose monitoring system with a lancet device to prick the finger.

Results

There was no statistically significant difference in the mean blood glucose concentration between the groups S and G in T1 (78.3 ± 18.2 vs. 74.3 ± 14.7, p > 0.05) and T2 (79.2 ± 18.3 vs. 84.9 ± 23.7, p > 0.05). The mean BGC was statistically significantly higher in group G in comparison to group S in the times 5 minutes before (80.2 ± 18.1 vs. 108.4 ± 16.7, p < 0.05) and 30 minutes after the end of surgery (80.9 ± 17.7 vs. 121.1 ± 17.4, p < 0.05).

Conclusion

There is a much lower increase in blood glucose concentration under spinal anesthesia than under general anesthesia. It is reasonable to suggest that the blood sugar concentration must be intraoperatively monitored in patients undergoing general anesthesia.

The Effects of Dexmedetomidine Administration on Postoperative Blood Glucose Levels in Diabetes Mellitus Patients Undergoing Spinal Anesthesia: A Pilot Study

Background

Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist with sedative and sympatholytic effects. It inhibits the stress response and insulin secretion. Therefore, postoperative changes to blood glucose levels were investigated when DEX was intraoperatively infused for sedation purposes in diabetic patients under spinal anesthesia.

Methods

Twenty diabetic patients were randomly allocated to two groups (n = 10). Group A patients were infused with DEX at a dose of 0.4 - 0.8 μg/kg/hour and group B (control) patients were infused with the same volume of normal saline. The blood glucose levels were measured preoperatively and at 1, 3, 6, 12, and 24 hours postoperatively.

Results

There was no statistically significant difference between the blood glucose levels in groups A and B up to 24 hours postoperatively (P = 0.088). A statistically significant difference in the blood glucose level was not demonstrated 24 hours after surgery in comparison with the baseline level in Group A. The blood glucose level significantly decreased at three hours in group B in comparison with the level at baseline (P = 0.007) and increased at 24 hours (P = 0.037).

Conclusions

An intraoperative DEX infusion maintains blood glucose levels at a constant level relative to baseline in diabetic patients within 24 hours postoperatively. The frequency of hyperglycemia was low in group A in the perioperative period compared with that in the control group (group B).

Epidural local anaesthetics versus opioid-based analgesic regimens for postoperative gastrointestinal paralysis, vomiting and pain after abdominal surgery

BACKGROUND

Gastrointestinal paralysis, nausea and vomiting and pain are major clinical problems following abdominal surgery. Anaesthetic and analgesic techniques that reduce pain and postoperative nausea and vomiting (PONV), while preventing or reducing postoperative ileus, may reduce postoperative morbidity, duration of hospitalization and hospital costs. This review was first published in 2001 and was updated by new review authors in 2016.

OBJECTIVES

To compare effects of postoperative epidural analgesia with local anaesthetics versus postoperative systemic or epidural opioids in terms of return of gastrointestinal transit, postoperative pain control, postoperative vomiting, incidence of anastomotic leak, length of hospital stay and costs after abdominal surgery.

SEARCH METHODS

We identified trials by conducting computerized searches of the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 12), MEDLINE (from 1950 to December 2014) and EMBASE (from 1974 to December 2014) and by checking the reference lists of trials retained. When we reran the search in February 2016, we added 16 potential new studies of interest to the list of 'Studies awaiting classification' and will incorporate these studies into formal review findings during the next review update.

SELECTION CRITERIA

We included parallel randomized controlled trials comparing effects of postoperative epidural local anaesthetic versus regimens based on systemic or epidural opioids.

DATA COLLECTION AND ANALYSIS

We rated the quality of studies by using the Cochrane 'Risk of bias' tool. Two review authors independently extracted data and judged the quality of evidence according to the GRADE (Grades of Recommendation, Assessment, Development and Evaluation Working Group) scale.

MAIN RESULTS

We included 128 trials with 8754 participants in the review, and 94 trials with 5846 participants in the analysis. Trials included in the review were funded as follows: charity (n = 19), departmental resources (n = 8), governmental sources (n = 15) and industry (in part or in total) (n = 15). The source of funding was not specified for the other studies.Results of 22 trials including 1138 participants show that an epidural containing a local anaesthetic will decrease the time required for return of gastrointestinal transit as measured by time to first flatus after an abdominal surgery (standardized mean difference (SMD) -1.28, 95% confidence interval (CI) -1.71 to -0.86; high quality of evidence; equivalent to 17.5 hours). The effect is proportionate to the concentration of local anaesthetic used. A total of 28 trials including 1559 participants reported a decrease in time to first faeces (stool) (SMD -0.67, 95% CI -0.86 to -0.47; low quality of evidence; equivalent to 22 hours). Thirty-five trials including 2731 participants found that pain on movement at 24 hours after surgery was also reduced (SMD -0.89, 95% CI -1.08 to -0.70; moderate quality of evidence; equivalent to 2.5 on scale from 0 to 10). From findings of 22 trials including 1154 participants we did not find a difference in the incidence of vomiting within 24 hours (risk ratio (RR) 0.84, 95% CI 0.57 to 1.23; low quality of evidence). From investigators in 17 trials including 848 participants we did not find a difference in the incidence of gastrointestinal anastomotic leak (RR 0.74, 95% CI 0.41 to 1.32; low quality of evidence). Researchers in 30 trials including 2598 participants noted that epidural analgesia reduced length of hospital stay for an open surgery (SMD -0.20, 95% CI -0.35 to -0.04; very low quality of evidence; equivalent to one day). Data on costs were very limited.

AUTHORS' CONCLUSIONS

An epidural containing a local anaesthetic, with or without the addition of an opioid, accelerates the return of gastrointestinal transit (high quality of evidence). An epidural containing a local anaesthetic with an opioid decreases pain after abdominal surgery (moderate quality of evidence). We did not find a difference in the incidence of vomiting or anastomotic leak (low quality of evidence). For open surgery, an epidural containing a local anaesthetic would reduce the length of hospital stay (very low quality of evidence).

Stress response in shoulder surgery under interscalene block, randomized controlled study comparing ultrasound guidance to nerve stimulation

Background:

Shoulder surgeries are known to cause moderate to severe pain. Many techniques have been used successfully to minimize that stress response including interscalene block. Ultrasound guided techniques are becoming widely spread and commonly used for regional anesthesia. The objective of the present randomized controlled study is to compare the ultrasound guidance with nerve stimulation for interscalene brachial plexus block (IBPB) regarding the effect on stress response.

Patients and Methods:

50 patients, American Society of Anesthesiologists physical status I, II, and III, undergoing shoulder surgery were enrolled in the current study. Group U patients (n = 25) received ultrasound guided IBPB and Group N patients (n = 25) received IBPB using nerve locator. IBPB was done under ultrasound guidance using the linear 13-6 MHz transducer of the SonoSite M-Turbo ultrasonic device. In both groups, venous blood samples to measure cortisol level and assess stress response as a primary outcome were collected.

Results:

The current study demonstrated that the stress response, as indicated by the cortisol level in blood, showed no significant difference in the preoperative blood level between Group U and Group N, as well as blood level after block and before skin incision. However, it differed significantly between the two groups postoperatively.

Conclusion:

The current study concluded that the use of ultrasound guidance for IBPB in shoulder surgeries offered a significant suppression of the stress response intraoperatively and postoperatively as indicated by the low cortisol level with less complications and easier technique compared to nerve location.

Chromogranin A and cortisol at intraoperative repeated noxious stimuli: Surgical stress in a dog model

Objectives:

Biomarkers representing sympathetic tone and the surgical stress response are measured to objectively evaluate surgical techniques and anaesthetic protocols. If a part of the intraoperative procedure is repeated on the contralateral organ, one animal may potentially serve as its own control and, if so, may minimize the problem of individual differences of the stress response to anaesthesia and surgery. This study aimed to investigate the use of chromogranin A for measurement of the intraoperative sympathetic tone. Additional aims were to investigate chromogranin A and cortisol as indicators of the intraoperative surgical stress response caused by repeated noxious stimuli in dogs subjected to ovariohysterectomy and thereby to investigate the possibility of one dog serving as its own control.

Methods:

Experiments were carried out on 10 dogs subjected to ovariohysterectomy. Perioperative blood samples (0–6) were collected after premedication, immediately before induction of anaesthesia (0), after induction of anaesthesia and before incision (1), before (2) and after (3) removal of the first ovary, after a 15-min pause before removal of the second ovary (4), after removal of the second ovary (5) and after closing the abdomen (6). Plasma chromogranin A and cortisol were analysed.

Results:

Plasma chromogranin A did not change. Plasma cortisol concentration did not change between before anaesthesia and opening of the abdomen. Plasma cortisol increased at removal of the first ovary. Cortisol did not change at removal of the second ovary but remained increased compared to initial sample.

Conclusion:

The results suggest chromogranin A is a poor indicator of intraoperative sympathetic tone during elective surgery in dogs. Cortisol measurement was useful for assessment of intraoperative noxious stimuli. However, at these test conditions, neither plasma chromogranin A nor plasma cortisol was useful for assessment of repeated intraoperative noxious stimuli where one dog served as its own control.

Cortisol and Insulin Levels during Major Gynaecological Operations: The influence of Two Anaesthetic Techniques

BACKGROUND: Metabolic and hormonal changes are noticed within the first few hours after surgical injury. These changes are influenced by the intensity, duration, type of injury, and the anaesthetic techniques.AIM: To investigate the effects of anaesthesia on cortisol, insulin and glucose concentrations during major gynaecological surgeries.METHODS: Forty patients were randomly allotted to receive either balanced general anaesthesia (n=20) or combined spinal epidural anaesthesia extending from T5 to S5 (n=20). Blood samples were collected for cortisol and glucose at preinduction, 1, 3 and 4 hours, and for insulin at preinduction and 24 hours after incision.RESULTS: The mean cortisol concentration was significantly lower 4 hours after incision with combined spinal epidural anaesthesia (19.96 ± 11.32) μg/dl than with balanced general anaesthesia (38.94 ± 10.6) μg/dl, p = 0.018. The mean insulin concentration, 24 hours after incision decreased with combined spinal epidural anaesthesia, but increased with balanced general anaesthesia p = 0.403. The mean glucose concentrations were significantly lower with combined spinal epidural anaesthesia than with balanced general anaesthesia during the 4 hour study period p ≤ 0.05.CONCLUSION: combined spinal epidural anaesthesia extending from T5 to S5 resulted in lower cortisol, insulin and glucose concentrations during major gynaecological surgeries. This may be of benefit in patients scheduled for surgical operations below the umbilicus.

Endocrinopathies in the cardiac ICU

The past several years have seen an increased appreciation of the potential role of the endocrine system in the recovery process following surgery for congenital heart disease. Many of the hormonal changes following cardiac surgery are adaptive and necessary, whereas activation of proinflammatory cytokine and chemokine responses and some of the metabolic changes following surgery are likely mediators leading to detrimental outcomes. Additionally, other hormonal perturbations may contribute to adverse outcomes. This review examines the pain and the stress response, thyroid function and hyperglycemia following cardiopulmonary bypass (CPB), and the potential role of corticosteroids in the pediatric cardiac critical care unit.

The anabolic effect of perioperative nutrition depends on the patient's catabolic state before surgery

OBJECTIVE

We tested the hypothesis that the anabolic effect of hypocaloric, isonitrogenous nutrition in patients undergoing colorectal surgery depends on the patient's preoperative catabolic state.

BACKGROUND

Although there is evidence to suggest that total parenteral nutrition more effectively spares protein in depleted than in nondepleted cancer patients, the influence of preoperative catabolism on the anabolic effects of hypocaloric nutrition in patients undergoing elective surgery is unknown.

METHODS

Seventeen patients undergoing colorectal surgery received intravenous infusion of glucose with amino acids. Feeding was administered over 72 hours, from 24 hours before until 48 hours after surgery. Glucose provided 50% of the patient's measured resting energy expenditure. Amino acids provided 20% of the resting energy expenditure. Whole-body leucine balance (difference between the incorporation of leucine into protein = protein synthesis and endogenous leucine release = proteolysis) was determined using L-[1-(13)C]leucine kinetics before and 2 days after surgery. We analyzed the association between the postoperative increase in leucine balance and the following factors: preoperative leucine balance, protein breakdown, weight loss, oxygen consumption, circulating concentrations of glucose, free fatty acids, insulin, glucagon, cortisol, albumin, age, duration of surgery, and blood loss.

RESULTS

Of 6 potentially relevant variables, 4 (weight loss, protein breakdown, albumin, and cortisol) were removed because they were not significant during the stepwise linear regression procedure. Leucine balance and age were the remaining 2 factors that remained with the final regression model: Δleucine balance = 19.1 - (0.20 × age [years]) - (0.58) × leucine balance(preOP)).

CONCLUSIONS

We demonstrate a significant association between the degree of preoperative catabolism, the patient's age, and the anabolic effect of hypocaloric nutrition (ClinicalTrials.gov registration ID: NCT01414946).

Continuous glucose monitoring in patients undergoing cardiac surgery

OBJECTIVES

Hyperglycemia is a prominent feature among patients exposed to major stress such as in cardiac surgery. The implementation of a continuous glucose monitoring system (CGMS) for glucose monitoring during cardiac surgery was assessed.

SUBJECTS AND METHODS

Fifty-nine consecutive patients who underwent cardiac surgery were monitored by CGMS. Patients' fluid glucose content, drug requirements, and hemodynamic and physiologic parameters were evaluated.

RESULTS

Of the 59 patients, 32 completed the monitoring with CGMS. Patients were divided into three groups: diabetes patients, patients without diabetes history who developed significant hyperglycemia perioperatively, and patients who did not develop hyperglycemia. Hyperglycemia was most frequently observed postoperatively. Hyperglycemic patients required significantly more insulin (81±40 vs. 34±37 units, P=0.005) and experienced an increased early complication rate, although this difference was not significant. CGMS erroneously detected late-phase operative and immediate postoperative hypoglycemia in approximately one-third of patients as reflected from venous blood sample measurements.

CONCLUSIONS

CGMS enables close monitoring and optimal control of blood glucose among patients undergoing major cardiac surgery, although its reliability is limited during the cardiac surgery phase and in the early postoperative period, because of incorrect hypoglycemic readings.

For patients undergoing pancreatoduodenectomy, epidural anesthesia and analgesia improves pain but increases rates of intensive care unit admissions and alterations in analgesics

OBJECTIVES

For some procedures, epidural anesthesia and analgesia (EAA) improves clinical outcomes. It is used during pancreatoduodenectomy (PD) to mitigate morbidities and shorten hospitalizations. Although widespread, the use of this practice has not been examined extensively. The objective of this study was to do so.

METHODS

A retrospective review of 42 patients who underwent PD was performed. Patients with and without EAA were compared. End points included intraoperative blood losses, perioperative fluid requirements, intensive care unit admissions, pain, bowel function, lengths of stay, morbidities, and mortalities.

RESULTS

Eighteen patients received EAA; 24 did not. Patients with EAA who reported less pain on postoperative day 2 (P = 0.03) were more likely to require intensive care unit admissions (P = 0.02) and required more frequent alterations of analgesics (P = 0.0001001). Epidural anesthesia and analgesia was associated with a nonsignificant increase in blood losses and fluid requirements. The groups did not differ in bowel function, lengths of stay, morbidities, or mortalities.

CONCLUSIONS

For patients undergoing PD, EAA was not associated with clinical benefits except for a modest reduction in postoperative pain, which was limited to a single day. Therefore, in this study, the clinical benefits of EAA seem underwhelming.

The effect of combined spinal-epidural anesthesia on stress responses during total knee replacement

BACKGROUND

Intraoperative stress may evoke various changes in hormonal secretion and autonomic nervous system activity. We designed this study to investigate the effect of combined spinal-epidural anesthesia on stress hormone responses.

METHODS

Thirty women more than 60 years of age, undergoing bilateral total knee replacement surgery were studied. Patients were randomized to receive either general anesthesia (group I), or combined spinal-epidural anesthesia (group II). Blood samples were obtained immediately before anesthesia induction, immediately after skin incision, after first knee prosthesis insertion, and end of operation, immediately for measurement of cortisol, epinephrine, and norepinephrine.

RESULTS

The plasma concentration of cortisol, epinephrine and norepinephrine were significantly lower in group II after the prosthesis insertion and at the end of operation, immediately. The plasma concentration of cortisol was significantly higher than basal values in both of two groups through the surgery.

CONCLUSIONS

Combined spinal-epidural anesthesia has the blocking effect of releasing catecholamine during total knee replacement surgery and immediately after the surgery. The effect of combined spinal-epidural anesthesia on stress responses during total knee replacement is better than that of general anesthesia.

Current perioperative treatment of patients with type 1 and type 2 diabetes

Diabetes mellitus is rapidly increasing, diabetic patients are likely to undergo surgical procedures more than non-diabetic patients, the hospital stay of diabetic patients is longer, and diabetic patients have increased mortality and morbidity. The correct treatment of diabetic patients in the perioperative period is crucial to improve clinical outcomes. Diabetic patients must be carefully evaluated for cardiovascular risk, keeping in mind micro- and macroangiopathic diabetic complications. Metabolic control deserves great attention because hyperglycemia is related to increased complications and worse outcomes. Insulin infusion regimens to achieve near normoglycemia must be implemented in surgical and critically ill patients.

Analgesia pós-operatória

JUSTIFICATIVAS E OBJETIVOS: A dor sempre foi uma das maiores preocupações do homem, entretanto, apesar dos progressos da ciência, ainda existem várias barreiras ao seu adequado tratamento, incluindo a falta de conhecimento por parte da equipe médica, sobre o mecanismo das diversas drogas e técnicas empregadas. O objetivo deste trabalho é abordar as principais drogas e técnicas empregadas no controle da dor pós-operatória, visando estimular o interesse sobre o assunto bem como aumentar a eficácia do tratamento dado aos pacientes. CONTEÚDO: Está ressaltada neste artigo, a importância da adequada analgesia pós-operatória, considerando as principais drogas e técnicas utilizadas no controle da dor, seus mecanismos de ação, posologias, vias de administração e efeitos colaterais, bem como a importância da integração de toda a equipe envolvida nos cuidados do paciente para o sucesso do tratamento. O tratamento inadequado da dor no pós-operatório não se justifica, pois há um arsenal considerável de drogas e técnicas analgésicas. O que se faz necessário, portanto, é que toda equipe, anestesistas, cirurgiões, e enfermeiros tenham conhecimento e estejam integrados na utilização deste arsenal.

Intrathecal morphine: effects on perioperative hemodynamics, postoperative analgesia, and stress response for total abdominal hysterectomy

Intrathecal opioids provide postoperative analgesia and hemodynamic stability by depressing the neuroendocrine response during the perioperative period. The effects of preoperative intrathecal morphine on perioperative hemodynamics, stress response, and postoperative analgesia were evaluated in patients undergoing abdominal hysterectomy with general anesthesia. A total of 24 patients were randomly assigned to the morphine group (n=12) or the control group (n=12). Patients in the morphine group were given intrathecal 5 microg/kg(-1) morphine before surgery. In all patients, general anesthesia was induced with 1 g/kg(-1) remifentanil, 2 mg/kg(-1) propofol, and 0.1 mg/kg(-1) vecuronium and was maintained with 1% to 2% sevoflurane-35% oxygen in N2O and remifentanil infusion. All patients received intravenous morphine patient-controlled analgesia after surgery. Postoperative pain was evaluated by means of a visual analogue scale. Blood samples were taken at 4 time points before and up to 4 hours after the start of surgery for assessment of plasma epinephrine, norepinephrine, and glucose. Mean arterial pressure (MAP), heart rate (HR), and adverse effects were recorded. Intraoperative hemodynamics was similar in both groups, but postoperative HR and MAP values at 4 h, 8 h, 12 h, and 20 h were significantly lower in the morphine group (P<.05). Postoperative VAS scores, total morphine consumption, and plasma epinephrine, norepinephrine, and glucose levels were significantly lower in the morphine group than in the control group (P<.05). Preoperative intrathecal morphine enhanced the quality of postoperative analgesia, decreased morphine consumption, and depressed the systemic stress response in patients undergoing total abdominal hysterectomy with general anesthesia.

[Adrenal cortex and steroids. Supplementary therapy in the perioperative phase]

Since the publication of two case reports that are considered to represent the first clinical demonstration of iatrogenic adrenal insufficiency, it has been the generally accepted practice to cover steroid-treated patients undergoing surgery with glucocorticoids in the perioperative period. Both the inclusion criteria for the patients and the extent of the substitution pattern have been selected on an empirical rather than on a rational basis. Scientific advances over the past 50 years in the knowledge of the hypothalamic-pituitary-adrenal system's physiology and the molecular mechanism of action of its biologically active components are, for the most part, not reflected in current clinical practice and instead seem to be ignored. Clinical and experimental evidence suggests, however, that even glucocorticoid-treated patients undergoing surgery do not require maximum stress doses of hydrocortisone, which should be reserved for the treatment of sepsis. With regard to the broad spectrum of efficacy of glucocorticoids and their side effects, revision and modification of the historical regimen appear prudent.

Randomized clinical trial of the anabolic effect of hypocaloric parenteral nutrition after abdominal surgery

BACKGROUND

The observed failure of hypocaloric nutrition to establish an anabolic state after surgery may reflect inadequate control for the type and quality of analgesia in the studies performed. This study was designed to test the hypothesis that hypocaloric nutrition induces anabolism in patients who receive effective segmental pain relief using perioperative epidural analgesia.

METHODS

Sixteen patients who underwent colorectal surgery and received epidural analgesia were randomly assigned to receive intravenous glucose either without (glucose only) or with amino acids (nutrition). Feeding was administered over 48 h from surgical skin incision until the second day after operation. Glucose provided 50 per cent of the patient's resting energy expenditure (REE). Amino acids were infused at rates that provided 20 per cent of REE. Leucine rate of appearance (Ra), leucine oxidation and non-oxidative leucine disposal (NOLD) were assessed by measuring L-[1-13C]leucine kinetics. A positive leucine balance, that is the difference between NOLD and leucine Ra, indicated anabolism.

RESULTS

After surgery, leucine Ra in the nutrition group was lower than that in the glucose only group (mean(s.d.) 88(25) versus 131(22) micromol per kg per h). The leucine balance remained negative in the glucose only group, whereas it became positive in the nutrition group (mean(s.d.) -24(3) versus 38(12) micromol per kg per h; P < 0.001).

CONCLUSION

Patients who receive hypocaloric parenteral nutrition can be rendered anabolic after colorectal surgery in the presence of epidural analgesia.

Comparison of the effects of clonidine and ketamine added to ropivacaine on stress hormone levels and the duration of caudal analgesia

BACKGROUND

The purpose of this study was to compare the analgesic quality and duration of ropivacaine 0.2% with the addition of clonidine (1 microg.kg(-1)) with that of ropivacaine 0.2% and the addition of ketamine (0.5 mg.kg(-1)) to that of ropivacaine 0.2% and also compare the postoperative cortisol, insulin and glucose concentrations, sampled after induction and 1 h later following caudal administration in children.

METHODS

According to the randomization, patients in the ropivacaine group (R; n = 25) received ropivacaine 0.2%, 0.75 ml.kg(-1); those in the clonidine group (RC; n = 25) received ropivacaine 0.2% 0.75 ml.kg(-1) plus clonidine 1 microg.kg(-1) and those in the ketamine/ropivacaine group (RK; n = 25) ropivacaine 0.2% 0.75 ml.kg(-1) plus ketamine 0.5 mg.kg(-1) (10 mg.ml(-1) concentration). Drugs were diluted in 0.9% saline (0.75 ml.kg(-1)) and prepared by a staff anesthesiologist not otherwise involved in the study. In all groups, the duration of analgesia, analgesic requirements, sedation and insulin, glucose, cortisol concentrations were recorded and statistically compared.

RESULTS

There were no significant differences among the three study groups with respect to age, weight or duration of surgery. Caudal administration of clonidine 1 microg.kg(-1) or ketamine 0.5 mg.kg(-1) induced a longer duration of analgesia (P < 0.05) compared with ropivacaine alone. Insulin levels were increased and cortisol reduced in all groups. Glucose concentration was increased in all groups and statistically significant (P < 0.05).

CONCLUSIONS

Addition of ketamine and clonidine to ropivacaine 0.2% 0.75 ml.kg(-1), when administered caudally in children, prolongs the duration of postoperative analgesia. The need for subsequent postoperative analgesic is also reduced. Caudal analgesia attenuates or allows partial changes to postoperative cortisol, insulin or blood glucose responses to surgery.

Strategies for managing the diabetic patient

Diabetes mellitus is now classified as either 'type 1' (failure of endogenous insulin production) or 'type 2' ('insulin resistance') and can be diagnosed if fasting blood glucose is >6.1 mmol/l (110mg/dl) on two separate occasions or there is unequivocal hyperglycaemia with acute metabolic decompensation or obvious symptoms. The prevalence of the disease is rising and may be as great as 12-14% in western populations aged over 40 years. Diabetes is complicated by micro- and macrovascular consequences of chronically elevated blood glucose concentrations, and diabetic patients are over-represented in hospital populations, particularly among patients requiring surgical interventions. It is associated with increased perioperative mortality and morbidity. Evidence is now accumulating that intensive glycaemic monitoring and the administration of insulin infusions to achieve tight glycaemic control are associated with an improvement of both perioperative mortality and morbidity.

Intensive Insulin Therapy for Critically III Patients

OBJECTIVE:

To evaluate the clinical outcomes of glycemic control of intensive insulin therapy and recommend its place in the management of critically ill patients.

DATA SOURCES:

Searches of MEDLINE (1966—March 2004) and Cochrane Library, as well as an extensive manual review of abstracts were performed using the key search terms hyperglycemia, insulin, intensive care unit, critically ill, outcomes, and guidelines and algorithms.

STUDY SELECTION AND DATA EXTRACTION:

All articles identified from the data sources were evaluated and deemed relevant if they included and assessed clinical outcomes.

DATA SYNTHESIS:

Mortality among patients with prolonged critical illness exceeds 20%, and most deaths are attributable to sepsis and multisystem organ failure. Hyperglycemia is common in critically ill patients, even in those with no history of diabetes mellitus. Maintaining normoglycemia with insulin in critically ill patients has been shown to improve neurologic, cardiovascular, and infectious outcomes. Most importantly, morbidity and mortality are reduced with aggressive insulin therapy. This information can be implemented into protocols to maintain strict control of glucose.

CONCLUSIONS:

Use of insulin protocols in critically ill patients improves blood glucose control and reduces morbidity and mortality in critically ill populations. Glucose levels in critically ill patients should be controlled through implementation of insulin protocols with the goal to achieve normoglycemia, regardless of a history of diabetes. Frequent monitoring is imperative to avoid hypoglycemia.

Vasoactive modulators during and after craniotomy: relation to postoperative hypertension

Hypertension after craniotomy is frequent. To establish an association between vasoactive modulators and postoperative hypertension, we followed the arterial blood pressure and plasma concentrations of selected substances in patients undergoing craniotomy. Twelve consecutive patients scheduled for operation of a supratentorial brain tumor were anesthetized with thiopental, fentanyl, isoflurane, and pancuronium. None of the patients had a history of arterial hypertension or were hypertensive before the operation. Arterial blood pressure and heart rate measurements were obtained preoperatively, after incision, during closure, and four times in the 50-minute interval after stopping isoflurane. At the same time, plasma concentrations of norepinephrine, epinephrine, renin, aldosterone, atrial natriuretic peptide, endothelin, and cortisol were measured. Data are given as mean +/- SD (range). The postoperative concentrations of these substances were significantly higher than the baseline concentrations measured preoperatively. Six of the patients developed postoperative hypertension defined as a mean arterial pressure (MAP) > 20% more than the baseline MAP (group H), and six had normal blood pressure postoperatively (group N). The mean value of the maximal postoperative MAPs measured in groups H and N, respectively, was 118 +/- 16 mm Hg (range: 96-132) and 103 +/- 9 mm Hg (range: 92-115) (P =.01). Only renin levels were higher intraoperatively in group H when compared to group N. However, postoperative levels of catecholamines, aldosterone, renin, and endothelin levels were higher in group H patients. The results suggest that in addition to an increased discharge of the sympathetic system, activation of the renin-angiotensin aldosterone system may also play an important role in the development of postoperative hypertension after craniotomy.

Local metabolic changes in subcutaneous adipose tissue during intravenous and epidural analgesia

BACKGROUND

This clinical study aimed at investigating the impact of postoperative thoracic epidural analgesia on extracellular glycerol concentration and glucose metabolism in subcutaneous adipose tissue, using the microdialysis technique. The sympathetic nervous activity, which can be attenuated by epidural anesthesia, influences lipolysis and the release of glycerol.

METHODS

Fourteen patients who underwent major abdominal or thoraco-abdominal surgery were studied postoperatively over 3 days. For postoperative analgesia the patients were prospectively randomized to receive either thoracic epidural analgesia with a bupivacaine/morphine infusion (EPI-group, n=6) or a continuous i.v. infusion of morphine (MO-group, n=8). The concentration of glycerol, glucose and lactate in the abdominal and deltoid subcutaneous adipose tissue were measured using a microdialysis technique.

RESULTS

The abdominal glycerol levels were equal in both groups. In the deltoid region of the EPI-group, glycerol concentrations started to increase on Day 2, and reached significantly higher levels on Day 3 compared with the MO-group. The glucose and lactate levels showed no differences between groups in the two regions.

CONCLUSION

The uniform glycerol levels in abdominal subcutaneous adipose tissue in conjunction with the difference in glycerol levels in the deltoid area indicate that the local lipolysis is different in the two study groups. This might be explained by a regional metabolic influence of thoracic epidural analgesia, possibly via the sympathetic nervous system.

Effect of epidural anesthesia and analgesia on perioperative outcome: a randomized, controlled Veterans Affairs cooperative study

OBJECTIVE

To test the hypothesis that epidural anesthesia and postoperative epidural analgesia decrease the incidence of death and major complications during and after four types of intraabdominal surgical procedures.

SUMMARY BACKGROUND DATA

Even though many beneficial aspects of epidural anesthesia have been reported, clinical trials of epidural anesthesia for outcome of surgical patients have shown conflicting results.

METHODS

The authors studied 1,021 patients who required anesthesia for one of the intraabdominal aortic, gastric, biliary, or colon operations. They were assigned randomly to receive either general anesthesia and postoperative analgesia with parenteral opioids (group 1) or epidural plus light general anesthesia and postoperative epidural morphine (group 2). The patients were monitored for death and major complications during and for 30 days after surgery, as well as for postoperative pain, time of ambulation, and length of hospital stay.

RESULTS

Overall, there was no significant difference in the incidence of death and major complications between the two groups. For abdominal aortic surgical patients, unlike the other three types of surgical patients, the overall incidence of death and major complications was significantly lower in group 2 patients (22%) than in group 1 patients (37%), stemming from differences in the incidence of new myocardial infarction, stroke, and respiratory failure between the two groups. Overall, group 2 patients received significantly less analgesic medication but had better pain relief than group 1 patients. In group 2 aortic patients, endotracheal intubation time was 13 hours shorter and surgical intensive care stay was 3.5 hours shorter.

CONCLUSIONS

The effect of anesthetic and postoperative analgesic techniques on perioperative outcome varies with the type of operation performed. Overall, epidural analgesia provides better postoperative pain relief. Epidural anesthesia and epidural analgesia improve the overall outcome and shorten the intubation time and intensive care stay in patients undergoing abdominal aortic operations.

Hormonal and metabolic stress responses after major surgery in children aged 0-3 years: a double-blind, randomized trial comparing the effects of continuous versus intermittent morphine

Children aged 0-3 yr were stratified for age and randomized to receive either continuous morphine (CM, 10 microg x kg(-1) x h(-1)) with three-hourly placebo boluses or intermittent morphine (IM, 30 microg x kg(-1) every 3 h) with a placebo infusion for postoperative analgesia. Plasma concentrations of epinephrine, norepinephrine, insulin, glucose and lactate were measured before and at the end of surgery and 6, 12 and 24 h after surgery. Pain was assessed with validated pain scales [the COMFORT scale and a visual analogue scale (VAS)] with the availability of additional morphine doses. Minor differences occurred between the randomized treatment groups, the oldest IM group (aged 1-3 yr) having a higher blood glucose concentration (P=0.003), mean arterial pressure (P=0.02) and COMFORT score (P=0.02) than the CM group. In the neonates, preoperative plasma concentrations of norepinephrine (P=0.01) and lactate (P<0.001) were significantly higher, while the postoperative plasma concentrations of epinephrine were significantly lower (P<0.001) and plasma concentrations of insulin significantly higher (P<0.005) than in the older age groups. Postoperative pain scores (P<0.003) and morphine consumption (P<0.001) were significantly lower in the neonates than in the older age groups. Our results show that continuous infusion of morphine does not provide any major advantages over intermittent morphine boluses for postoperative analgesia in neonates and infants.

Understanding the mechanisms by which isoflurane modifies the hyperglycemic response to surgery

We studied the effect of anesthesia on the kinetics of perioperative glucose metabolism by using stable isotope tracers. Twenty-three patients undergoing cystoprostatectomy were randomly assigned to receive epidural analgesia combined with general anesthesia (n = 8), fentanyl and midazolam anesthesia (n = 8), or inhaled anesthesia with isoflurane (n = 7). Whole-body glucose production and glucose clearance were measured before and during surgery. Glucose clearance significantly decreased during surgery independent of the type of anesthesia. Epidural analgesia caused a significant decrease in glucose production from 10.2 +/- 0.4 to 9.0 +/- 0.4 micromol. kg(-1). min(-1) (P < 0.05), whereas the plasma glucose concentration was not altered (before surgery, 5.0 +/- 0.2 mmol/L; during surgery, 5.2 +/- 0.1 mmol/L). Glucose production did not significantly change during fentanyl/midazolam anesthesia (before surgery, 10.5 +/- 0.5 micromol. kg(-1). min(-1); during surgery, 10.1 +/- 0.5 micromol. kg(-1). min(-1)), but plasma glucose concentration significantly increased from 4.8 +/- 0.1 mmol/L to 5.3 +/- 0.2 mmol/L during surgery (P < 0.05). Isoflurane anesthesia caused a significant increase in plasma glucose concentration (from 5.2 +/- 0.1 mmol/L to 7.2 +/- 0.5 mmol/L) and glucose production (from 10.8 +/- 0.5 micromol. kg(-1). min(-1) to 12.4 +/- 1.0 micromol. kg(-1). min(-1)) (P < 0.05). Epidural analgesia prevented the hyperglycemic response to surgery by a decrease in glucose production. The increased glucose plasma concentration during fentanyl/midazolam anesthesia was caused by a decrease in whole-body glucose clearance. The hyperglycemic response observed during isoflurane anesthesia was a consequence of both impaired glucose clearance and increased glucose production.

IMPLICATIONS

Epidural analgesia combined with general anesthesia prevented the hyperglycemic response to surgery by decreasing endogenous glucose production. The increased glucose plasma concentration in patients receiving fentanyl/midazolam anesthesia was caused by a decrease in whole-body glucose clearance. The hyperglycemic response observed during inhaled anesthesia with isoflurane was a consequence of both impaired glucose clearance and increased glucose production.

The effects of epidural block on the distribution of lymphocyte subsets and natural-killer cell activity in patients with and without pain

Although epidural anesthesia prevents immune suppression during surgery, no reports have elucidated how epidural block affects immune response in nonsurgical patients. We examined changes in proportion of lymphocyte subsets and in natural-killer (NK) cell activity in patients with and without pain. Fifteen patients with pain (Pain group) and 15 preoperative patients without pain (Preoperative group) received three different treatments in random order: epidural block with 7 mL 1% lidocaine, epidural injection of an identical volume of normal saline, and IV injection of 1 mg/kg lidocaine. Blood samples were drawn before and after 30, 60, and 120 min of treatment. During epidural block at 30 and 60 min, both groups showed significantly decreased epinephrine, norepinephrine, and cortisol levels, and the proportion of NK cells decreased, whereas the CD4+/CD8+ ratio increased significantly. NK cell activity in both groups decreased significantly at 30 and 60 min. At 120 min, the variables had all returned to preblock values. During treatments with saline and IV lidocaine, neither group showed significant changes in any of the above variables. We conclude that epidural block causes a transient and significant alteration of lymphocyte subsets and NK cell activity regardless of pain status.

Preoperative dextrose does not affect spinal-induced hypotension in elective Cesarean section

PURPOSE

To determine if preoperative intravenous dextrose affects the incidence and ease of treatment of spinal-induced hypotension in parturients having elective Cesarean section under spinal anesthesia.

METHODS

In this prospective, double-blind study, following informed consent, 119 ASA I, II parturients for elective Cesarean section were randomized to receive intravenously either dextrose 5% in normal saline (Group D) or normal saline (Group NS) at 125 ml x hr(-1) for two hours prior to delivery. Following a bolus of 15 ml x kg(-1) normal saline iv, spinal anesthesia was induced with hyperbaric bupivacaine 0.75%, fentanyl and morphine. Hypotension (systolic blood pressure <100 mm Hg or >20% decrease) was treated with fluids and/or vasopressor.

DATA COLLECTED

demographics, blood glucose concentrations (fasting, time of spinal, delivery), blood pressure (baseline, one minute intervals from spinal to delivery), neonatal Apgar scores, umbilical blood gas analyses, glucose and lactate concentrations.

RESULTS

There was no difference between the two groups in the rate of hypotension (P = 0.272). All parturients who experienced hypotension received fluids, and there was also no difference between the groups in vasopressor requirement [mean dose of ephedrine: Group D = 21.6 mg (95% CI 15.1-28.2), Group NS = 16 mg (95% CI 12.0-20.5)].

CONCLUSION

The routine administration of dextrose 5% at a rate of 5.22 g x hr(-1) preoperatively does not affect the hypotension rate, or make it easier to treat.

Spinal but not general anesthesia increases the ratio of T helper 1 to T helper 2 cell subsets in patients undergoing transurethral resection of the prostate

Surgical stress and anesthesia cause immunosuppression that may predispose patients to postoperative infections. T helper lymphocytes play a major role in the immune response by controlling cell-mediated and humoral immunity. The type of immune response generated is determined by the differentiation of precursor T helper cells into Th1 or Th2 cells. Each cell subset secretes a particular array of cytokines that further augment the differentiation into that subset. Th1 cells produce interferon gamma and are responsible for cell-mediated immunity. Th2 cells produce interleukin-4 and are more effective in inducing humoral immunity. Cytokine concentrations are altered during surgery and anesthesia, which may effect Th cell predominance and, therefore, subsequent immune responses. We determined Th1 to Th2 cell ratios in patients undergoing transurethral resection of the prostate (TURP) using either spinal or general anesthesia. Mononuclear cells were isolated before anesthesia, immediately after surgery, and after 24 h from patients undergoing TURP, 10 under general anesthesia and 9 under spinal anesthesia. T helper cell subsets were quantified by using flow cytometry, and the ratio of Th1 to Th2 cells was calculated. Th1 to Th2 ratios in patients receiving spinal anesthesia increased over the three time points studied (P = 0.029) but did not change in patients who had general anesthesia (P = 0.11). At 24 h, Th1 to Th2 ratios were significantly higher in the spinal group than in patients who received general anesthesia (P = 0.0157). Total T helper cell numbers remained constant. These data suggest that, from an immunological viewpoint, spinal anesthesia, but not general anesthesia, benefits the patient by maintaining Th1 cell numbers, thereby promoting cellular immunity.

IMPLICATIONS

Spinal anesthesia may result in less immunosuppression after surgery. We found that the ratio of T helper 1 to T helper 2 cells was higher in patients undergoing prostate surgery by spinal rather than general anesthesia. Th1 cells promote protective immune responses that may result in fewer postoperative infections.

[Benefit-risk and monitoring modalities of different techniques and methods of postoperative analgesia]

This review aimed to determine the benefits-risks ratio of postoperative analgesia. The various agents usually used for intravenous postoperative analgesia (paracetamol, NSAID's, opioids), and the techniques for postoperative analgesia (PCA, epidural, perinervous block) are analysed. The rules proposed for the monitoring of postoperative analgesia are considered.