The plasma ACTH, AVP, CRH and catecholamine responses to conventional and laparoscopic cholecystectomy

Is Preoperative Adrenal Insufficiency Screening Necessary for Cardiovascular Thoracic Surgery Patients?

Background: The association between adrenal insufficiency (AI) and the treatment outcomes of cardiothoracic surgery patients has been little reported. The aims of this study were to investigate the incidence of AI and to compare the post-surgical outcomes of patients with perioperatively treated AI and patients with a normal adrenal response. Methods: A 1.5-year prospective study was conducted in 98 patients scheduled for cardiothoracic surgery. Patients were categorized as either AI or normal-adrenal-response patients. Those with AI were treated with stress doses of glucocorticoid perioperatively. The post-surgical outcomes of patients with AI and of those with a normal adrenaline response were analyzed using multivariable analysis. Results: The overall incidence of AI was 34.7%. There were no statistically significant differences in post-surgical outcomes, including prolonged hospital stay, postoperative infection, prolonged inotropic drug use and relative AI, between the two groups. Only the rate of hyperglycemia requiring insulin infusion was significantly higher in the AI group than in the non-AI group (OR = 14.15, 95% CI = 1.44-138.60, p = 0.02). Conclusions: The proper diagnosis and management of AI can result in surgical outcomes in AI patients comparable to those of normal-adrenal-response patients. Non-life-threatening hyperglycemia requiring insulin infusion was found only in the AI group.

Cortisol secretory patterns in deep and moderate neuromuscular blockades in laparoscopic surgery under total intravenous anesthesia: A prospective, single-blinded, randomized controlled trial

BACKGROUND

Neuroendocrine stress response induces physiological changes depending on the type of surgery and anesthesia. Although the optimal depth of neuromuscular blockade for reducing this response remains unknown, deep neuromuscular blockade is known to improve the surgical environment. Therefore, we hypothesized that a patient's stress response would be lower in surgical procedures under deep neuromuscular blockade than under moderate neuromuscular blockade.

METHODS

This prospective, randomized, single-blind study enrolled 72 patients who underwent laparoscopic gynecological surgery under general anesthesia and were assigned to group D (deep blockade: target train-of-four 0 and posttetanic count ≥ 1) or group M (moderate blockade: target train-of-four count 1-3). The primary endpoints were changing patterns in cortisol and adrenocorticotrophic hormone levels; the secondary endpoints were patient outcomes, such as hemodynamic variables, serum glucose level, postoperative pain in the postanesthesia care unit, and hospital stay.

RESULTS

The baseline characteristics were comparable between the 67 patients included in the 2 groups (34 in group M and 33 in group D). Cortisol and adrenocorticotrophic hormone levels increased perioperatively in both groups but without significant intergroup differences. Serum glucose level increased perioperatively and decreased postoperatively, but without a significant intergroup difference. Postoperative pain, fentanyl requirement in the postanesthesia care unit, and hospital stay were also comparable.

CONCLUSIONS

Compared with moderate neuromuscular blockade, deep neuromuscular blockade improved the surgical environment without significant intergroup differences in the hormonal stress response.

Peri-operative steroid management in the paediatric population

BACKGROUND

Patients with adrenal insufficiency are at risk of adrenal crisis, a potentially life-threatening emergency in the peri-operative period due to their attenuated ability to mount a cortisol response. There is a lack of standardization regarding peri-operative stress-dose glucocorticoids in paediatric clinical practice with the absence of agreed protocols. For the individual patient, the risk of adrenal crisis must be weighed against the potential adverse clinical outcomes associated with unnecessary or supra-physiologic glucocorticoid dosing in susceptible patients. Specific clinical concerns in the paediatric population include osteopenia, growth restriction and increased risk of cardiovascular disease in adulthood. This review aimed to identify and evaluate available literature in the field of peri-operative stress-dose glucocorticoids.

METHODS

A comprehensive literature search was conducted to construct a narrative review.

RESULTS

The outcome of this review identified that paediatric patients, unlike adults, do not show a graded response to surgical stress with implications for glucocorticoid stress dose regimens for general anaesthesia and less invasive surgical procedures. The studies highlight a lack of information on physiological steroid responses to stress situations and differences in the approach to glucocorticoid replacement strategies in the paediatric population.

CONCLUSION

The review identified there is a lack of high-quality paediatric-specific studies evaluating appropriate stress-dose glucocorticoid regimens in paediatric patients with or at risk of adrenal insufficiency. Further research is needed to establish clear evidence-based clinical guidelines for paediatric peri-operative practice regarding steroid stress dosing in adrenal insufficiency. Current knowledge would suggest that a balanced view of risks and benefits should be taken appropriate to the clinical context, to dictate peri-operative stress-dose glucocorticoids use that permits safe perioperative management.

The relationship between early post-operative ACTH / cortisol following pituitary surgery and long-term glucocorticoid requirement - Do ultradian rhythms matter?

OBJECTIVE

To determine whether early (4-8h) post-operative ACTH after trans-sphenoidal surgery (TSS) predicts long-term hypothalamic-pituitary-adrenal (HPA) axis function and to investigate early morning day 1 ACTH/cortisol variability using rapid sampling.

DESIGN

Prospective observational study.

METHODS

Participants undergoing TSS were included; those treated with glucocorticoids pre-operatively received 100 mg intravenous hydrocortisone on anaesthetic induction. ACTH and cortisol were measured post-operatively at + 4h and + 8h after induction and on day 1 every 10 minutes between 0700h and 0900h.

PRIMARY OUTCOME

glucocorticoid requirement at 6 months.

RESULTS

Nineteen participants (10F, 9M): 6/19 (32%) were treated with replacement glucocorticoids pre-operatively; 4 had ceased by 6 weeks post-operatively. One patient developed new hypopituitarism post-operatively meaning 3/19 (16%) required glucocorticoids at 6 months. Post-operative + 4h ACTH < 14.3 pmol/L (65 ng/L) predicted secondary adrenal insufficiency (SAI) (sensitivity 100%, specificity 75%), whilst no participant with a post-operative + 4h ACTH ≥ 14.3 pmol/L (65 ng/L) required glucocorticoids at 6 months. Day 1 ACTH and cortisol showed a significant circadian fall between 0700h-0900h; ACTH 4.2 pmol/L (IQR 2.9-5.9) to 3.7 pmol/L (IQR 2.9-5.1) P = .006 and cortisol 549 nmol/L (IQR 337-618) to 439 nmol/L (IQR 315-606) P < .001, with clinically insignificant ultradian secretory pulses.

CONCLUSIONS

No participant with a post-operative + 4h ACTH ≥ 14.3 pmol/L (65 ng/L) required glucocorticoids at 6 months; however, given only 3/19 participants had the primary outcome of interest, this must be confirmed in a larger cohort. The timing of a day 1 morning cortisol between 0700h and 0900h influences the accuracy of a single cut-off to diagnose SAI after pituitary surgery.

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.

The Fluctuations of Melatonin and Copeptin Levels in Blood Serum During Surgical Stress Regarding the Pediatric Population

INTRODUCTION

Copeptin is known to be associated with heart damage, while melatonin is a regulatory hormone related to circadian rhythm and represents the levels of inflammation in the body.

METHODS AND PATIENTS

The aim of the study was to measure in different surgeries the levels of copeptin and melatonin at different times before and after surgery in 56 patients aged from 5 days to 13.6 years. We measured copeptin in 50-microL serum and plasma samples from patients before surgery, immediately after surgery, and 24 hours after surgery. The measured levels are aligned with the published GC / MS data, and the sensitivity of the analysis is such that serum and plasma levels can only be measured by rapid extraction. The measurement was made before surgery, immediately after surgery, and 24 hours after surgery.

RESULTS

The multifactorial statistical analysis revealed a statistically significant difference between the 24-hour postoperative copeptin values in group 1 (mild-moderate gravity surgery) and group 2 (severe surgery) of the severity of the surgery. Post-hoc tests with Tukey correction for age groups in multiple comparisons of the multifactorial analysis revealed a statistically significant difference (p <0.05) between 24-hour postoperative melatonin values in age groups 3 (3-6 years) and 5 (6-12 years old). The age group 3 showed significantly (p <0.05) lower 24 hours postoperative melatonin values compared to the age group 5 (6-12 years). Again, these 3-6-year-olds were more likely to have inflammation due to the severity of the surgery and the presence of inflammation after the surgery.

DISCUSSION

In summary, copeptin is a reliable biomarker for assessing a patient's health both preoperatively and postoperatively. Copeptin and melatonin are two independent agents and are not related to each other, and more studies will be needed with more patients of the same age and with the same underlying disease to assess their diagnostic value. Finally, melatonin could be considered an indicator of inflammation on its own and based on pre-and post-surgery values to determine a patient's health status and take appropriate actions.

Postoperative Copeptin as a Biomarker for Development of Diabetes Insipidus Following Hypothalamic-Pituitary Surgery

OBJECTIVE

Copeptin is a surrogate marker of arginine vasopressin release with better stability and simplicity of measurement. Postoperative copeptin levels may guide clinicians in stratifying patients who need close monitoring of fluid balance. The objective is to determine whether copeptin is a predictive marker of postoperative diabetes insipidus (DI).

METHODS

This is a prospective diagnostic study. Patients who underwent neurosurgical intervention of the sellar-suprasellar regions were recruited. Serum copeptin levels were measured before and after surgery, within 24 hours. Logistic regression analysis and diagnostic performance measures were calculated to determine the relationship between postoperative copeptin levels and DI.

RESULTS

Of 82 patients, 26 (31.7%) developed postoperative DI, with 7 patients (8.5%) having permanent DI. The samples for copeptin measurement were taken at 13 ± 2.1 hours postoperatively. From the receiver operating characteristic analysis, low postoperative copeptin levels (<2.5 pmol/L) demonstrated an acceptable ability to predict DI (area under the curve, 0.72; 95% CI, 0.60-0.84). Discriminative power was stronger in the permanent DI group (area under the curve, 0.82; 95% CI, 0.64-1.00). Postoperative copeptin levels <2.5 pmol/L were associated with DI (specificity > 91%). However, postoperative copeptin levels >20 pmol/L were rarely associated with DI, with a negative predictive value of 100%.

CONCLUSIONS

In patients undergoing sellar-suprasellar interventions, low postoperative copeptin levels within the first postoperative day predict postoperative DI, whereas high levels exclude it. Copeptin measurement should be applied in the clinical practice of postoperative care in patients following hypothalamic-pituitary surgery. This study may expand the potential use of copeptin, including in the Asian population.

The cortisol stress response induced by surgery: A systematic review and meta-analysis

OBJECTIVE

Surgery is a stressor that can be categorized by duration and severity and induces a systemic stress response that includes increased adrenal cortisol production. However, the precise impact of surgical stress on the cortisol response remains to be defined.

DESIGN

We performed a systematic review and meta-analysis to assess the cortisol stress response induced by surgery and to stratify this response according to different parameters.

METHODS

We conducted a comprehensive search in several databases from 1990 to 2016. Pairs of reviewers independently selected studies, extracted data and evaluated the risk of bias. Cortisol concentrations were standardized, pooled in meta-analysis and plotted over time.

RESULTS

We included 71 studies reporting peri-operative serum cortisol measurements in 2953 patients. The cortisol response differed substantially between moderately/highly invasive and minimally invasive surgical procedures. Minimally invasive procedures did not show a peri-operative cortisol peak, whereas more invasive surgeries caused a cortisol surge that was more pronounced in older subjects, women and patients undergoing open surgery and general anaesthesia. The duration of the procedure and the use of etomidate for induction of anaesthesia did not affect the cortisol response.

CONCLUSIONS

The peri-operative cortisol stress response is dynamic and influenced by patient-specific, surgical and anaesthetic features. However, the available evidence is derived from highly heterogeneous studies, with only two of 71 studies measuring cortisol by mass spectrometry, which currently prevents a precise and reproducible definition of this response.

Impact of Preoperative Exclusive Enteral Nutrition on Postoperative Complications and Recurrence After Bowel Resection in Patients with Active Crohn's Disease

BACKGROUND

The impact of preoperative enteral nutrition (EN) on postoperative complications and recurrence in Crohn's disease (CD) has not been investigated to date. The purpose of the present study was to determine the effect of preoperative exclusive EN on postoperative complications and recurrence after bowel resection in patients with active CD.

METHODS

Patient data were obtained from a prospectively maintained database. 81 patients who received bowel resection for ileal or ileocolonic CD were studied. Before operation, 42 CD patients received exclusive EN for 4 weeks, and the other patients had no nutritional therapy. All patients were followed up regularly for 2 years after surgery, and ileocolonoscopy was performed every 6 months after bowel resection.

RESULTS

Patients receiving exclusive EN had a dramatic improvement of nutritional (BMI, albumin, pre-albumin, and Hb) and inflammatory (CRP and CDAI) status compared with baseline after the EN therapy for 4 weeks (P < 0.05). Furthermore, significantly lower incidence of both infectious and non-infectious complications was observed in patients receiving exclusive EN compared with those received no nutritional therapy (P < 0.05). Exclusive EN therapy for 4 weeks significantly reduced endoscopic recurrence rates after resection for CD 6 months after operation. However, during the 2-year follow-up, incidence of clinical recurrence was similar in both groups (P > 0.05).

CONCLUSIONS

Preoperative exclusive EN therapy for 4 weeks reduced postoperative complications, which may be associated with improvement of nutritional and inflammatory status in patients with active CD.

The impact of peri-operative dexamethasone administration on the normal hypothalamic pituitary adrenal response to major surgical procedures

BACKGROUND

Surgical procedures are associated with activation of the hypothalamic-pituitary-adrenal axis (HPA). Studies examining HPA dynamics peri-operatively are limited and the modulating influence of peri-operatively administered glucocorticoids on that is not well established. This investigation examined alterations in HPA function and the impact of dexamethasone (DEX) administration during the peri-operative period.

METHODS

We examined HPA function in 297 patients with normal function who had surgical procedures including pituitary mass resection (n = 191), craniotomy (n = 17) and other thoracic/ abdominal/ pelvic surgeries (n = 89). HPA function was assessed by frequent measurements of parameters defining adrenal function: ACTH, cortisol, DHEA and DHEA-S levels for 48 h. DEX was administered as a single dose (2-10 mg) to 30 and as multiple doses (12-36 mg) to 21 patients. The data of DEX-treated subjects within each group were similar and were combined together.

RESULTS

Pre-operative data were similar for patients having different surgical procedures. Without DEX exposure, ACTH increased to 225 ± 100 ng/L at 2-4 h and gradually declined to baseline values by 36 h while cortisol levels peaked (39.2 ± 13.2 ug/dL) at 6-8 h declining gradually thereafter. Cortisol rise was paralleled by an equimolar increase in DHEA and a subsequent increase in DHEA-S levels. Single doses of DEX did not influence ACTH or cortisol secretion but suppressed the expected rise in DHEA and DHEA-S levels. Multiple doses of DEX suppressed ACTH and cortisol after the 15th postoperative hour and completely blocked the expected rise in DHEA and DHEA-S levels.

CONCLUSIONS

The data provide a detailed overview of HPA function in a large number of subjects who had major surgical procedures. Single and large doses of DEX did not suppress ACTH or cortisol secretion but suppressed adrenal androgen secretion. It took multiple doses of DEX to partially suppress ACTH and cortisol secretion in the peri-operative period.

The Relationship between Ghrelin and Copeptin Levels, and Anxiety and Depression Levels in Suicide Attempts

Objective

It was aimed to detect acylated ghrelin (AG), unacylated ghrelin (UG) and copeptin levels in patients with suicide attempts and to determine if these biomarkers are risk factors for suicide attempts.

Methods

Serum copeptin, AG and GU levels were screened in 128 patients who were admitted to emergency department with suicide attempts and 59 healthy controls. Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) were applied simultaneously, and the data were compared statistically.

Results

AG, UG and copeptin levels were higher in the patient group compared with the healthy control group. BAI scores of patients were found to be positively correlated with BDI scores. While there was a significant difference (p=0.0064) between psychiatric and non-psychiatric patients with suicide attempts in terms of BAI scores, there were no differences in BDI scores and levels of biomarkers. We found significantly increased BDI and BAI scores and increased levels of AG, UG and copeptin in psychiatric and non-psychiatric patients compared with healthy individuals. The specificities yielded by receiver operating characteristic curve analysis in patients with suicide attempts were as follows: 91.53% for AG, 72.88% for UG and 94.92% for copeptin.

Conclusion

Serum levels of AG, UG and copeptin increase with increasing anxiety and depression in patients with suicide attempts. Increased levels of AG, UG and copeptin could be considered a risk factor for suicide attempts.

Diagnosis and treatment of adrenal insufficiency including adrenal crisis: a Japan Endocrine Society clinical practice guideline [Opinion]

This clinical practice guideline of the diagnosis and treatment of adrenal insufficiency (AI) including adrenal crisis was produced on behalf of the Japan Endocrine Society. This evidence-based guideline was developed by a committee including all authors, and was reviewed by a subcommittee of the Japan Endocrine Society. The Japanese version has already been published, and the essential points have been summarized in this English language version. We recommend diagnostic tests, including measurement of basal cortisol and ACTH levels in combination with a rapid ACTH (250 μg corticotropin) test, the CRH test, and for particular situations the insulin tolerance test. Cut-off values in basal and peak cortisol levels after the rapid ACTH or CRH tests are proposed based on the assumption that a peak cortisol level ≥18 μg/dL in the insulin tolerance test indicates normal adrenal function. In adult AI patients, 15-25 mg hydrocortisone (HC) in 2-3 daily doses, depending on adrenal reserve and body weight, is a basic replacement regime for AI. In special situations such as sickness, operations, pregnancy and drug interactions, cautious HC dosing or the correct choice of glucocorticoids is necessary. From long-term treatment, optimal diurnal rhythm and concentration of serum cortisol are important for the prevention of cardiovascular disease and osteoporosis. In maintenance therapy during the growth period of patients with 21-hydroxylase deficiency, proper doses of HC should be used, and long-acting glucocorticoids should not be used. Education and carrying an emergency card are essential for the prevention and rapid treatment of adrenal crisis.

Perioperative Diastolic Dysfunction in Patients Undergoing Noncardiac Surgery Is an Independent Risk Factor for Cardiovascular Events

Background

The prognostic value of perioperative diastolic dysfunction (PDD) in patients undergoing noncardiac surgery remains uncertain, and the current guidelines do not recognize PDD as a perioperative risk factor. This systematic review aimed to investigate whether existing evidence supports PDD as an independent predictor of adverse events after noncardiac surgery.

Methods

Ovid MEDLINE, PubMed, EMBASE, the Cochrane Library, and Google search engine were searched for English-language citations in April 2015 investigating PDD as a risk factor for perioperative adverse events in adult patients undergoing noncardiac surgery. Two reviewers independently assessed the study risk of bias. Extracted data were verified. Random-effects model was used for meta-analysis, and reviewers’ certainty was graded.

Results

Seventeen studies met eligibility criteria; however, 13 contributed to evidence synthesis. The entire body of evidence addressing the research question was based on a total of 3,876 patients. PDD was significantly associated with pulmonary edema/congestive heart failure (odds ratio [OR], 3.90; 95% CI, 2.23 to 6.83; 3 studies; 996 patients), myocardial infarction (OR, 1.74; 95% CI, 1.14 to 2.67; 3 studies; 717 patients), and the composite outcome of major adverse cardiovascular events (OR, 2.03; 95% CI, 1.24 to 3.32; 4 studies; 1,814 patients). Evidence addressing other outcomes had low statistical power, but higher long-term cardiovascular mortality was observed in patients undergoing open vascular repair (OR, 3.00; 95% CI, 1.50 to 6.00). Reviewers’ overall certainty of the evidence was moderate.

Conclusion

Evidence of moderate certainty indicates that PDD is an independent risk factor for adverse cardiovascular outcomes after noncardiac surgery.

High-dose remifentanil suppresses stress response associated with pneumoperitoneum during laparoscopic colectomy

PURPOSE

Although laparoscopic surgery is minimally invasive, it produces stress responses to an extent similar to that of conventional laparotomy. Both epidural anesthesia and remifentanil intravenously (i.v.), combined with general anesthesia, provide stable hemodynamics during laparoscopic surgery. However, it has not been elucidated whether epidural anesthesia and remifentanil are associated with suppression of autonomic and neuroendocrine stress responses. This study aimed to clarify whether thoracic epidural anesthesia (TEA) or remifentanil suppresses stress responses during laparoscopic surgery.

METHODS

We assigned 60 patients undergoing laparoscopic colectomy to three groups anesthetized with 40 % oxygen-air-sevoflurane plus either TEA (TEA group), continuous infusion of remifentanil 0.25 μg/kg/min [low-dose (LD) group], or 1.0 μg/kg/min [high-dose (HD) group] (n = 20 each group). Plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol, antidiuretic hormone (ADH), and catecholamines were measured immediately before anesthesia induction, and 30 and 90 min after the start of pneumoperitoneum.

RESULTS

All groups showed no significant changes in hemodynamics during the course of anesthesia. Compared with TEA, both high-dose and low-dose remifentanil significantly suppressed increases in ACTH, ADH, and cortisol during pneumoperitoneum. Plasma adrenaline showed no significant changes during pneumoperitoneum in any group. Compared with TEA, low-dose remifentanil produced significantly higher plasma concentrations of noradrenaline and dopamine during pneumoperitoneum.

CONCLUSION

Notwithstanding similar hemodynamic responses in all groups, only high-dose remifentanil suppressed both sympathetic responses and the hypothalamus-pituitary-adrenal axis. This result indicates that of these three anesthesia regimens, high-dose remifentanil seems most suited for laparoscopic surgery.

The impact of acute mental stress on vascular endothelial function: evidence, mechanisms and importance

Cardiovascular disease is a principle cause of morbidity and mortality worldwide, and it has a complex etiology that involves lifestyle factors such as psychosocial stress. Recent evidence suggests that temporary impairments in vascular endothelial cell function may contribute to the relationship between stress and cardiovascular disease. Indeed, impaired endothelial function has been observed to occur transiently (lasting up to 1.5h) following mental stress, and such periods of impairment could accumulate to become clinically relevant over the long term. The finding of acute stress induced endothelial dysfunction is not universal however, and both physiological (e.g. sympathetic nervous system and hypothalamic-pituitary-adrenal axis reactivity), and methodological factors contribute to the conflicting results. A clear understanding of the interaction between stress response activation and endothelial function is critical to elucidating the complexities of the relationship between psychosocial stress and cardiovascular disease. Therefore, the purpose of this review is: 1) to briefly describe the importance of vascular endothelial function and how it is assessed, 2) to review the literature investigating the impact of acute mental stress on endothelial function in humans, identifying factors that may explain contradictory results, and 3) to summarize our current understanding of the mechanisms that may mediate an acute mental stress-endothelial function interaction.

Spinal-general anaesthesia decreases neuroendocrine stress response in laparoscopic cholecystectomy

OBJECTIVE

A randomized clinical study to compare the stress response to laparoscopic cholecystectomy during spinal-general anaesthesia and epidural- general anaesthesia.

METHODS

Women undergoing elective laparoscopic chole cystectomy were assigned to receive either spinal anaesthesia (SA group; n = 12) or epidural anaesthesia (EA group; n = 12), in addition to general anaesthesia. Plasma concentrations of cortisol, adrenocorticotrophic hormone (ACTH), noradrenaline, adrenaline and total catecholamines were measured pre- and intraoperatively.

RESULTS

Intraoperative cortisol, noradrenaline and total catecholamine levels were significantly lower in the SA group compared with the EA group. When pre- and intraoperative values were compared, the SA group showed a decrease in adrenaline, noradrenaline and total catecholamine levels, and the EA group showed an increase in ACTH and noradrenaline levels.

CONCLUSIONS

The type of regional anaesthesia significantly affected the stress response: spinal anaesthesia produced a more favourable endocrine response than epidural anaesthesia. Spinal-general anaesthesia may reduce postoperative morbidity in laparoscopic cholecystectomy.

Applications of Steroid in Clinical Practice: A Review

Steroids are perhaps one of the most widely used group of drugs in present day anaesthetic practice, sometimes with indication and sometimes without indications. Because of their diverse effects on various systems of the body, there has been renewed interest in the use of steroids in modern day anaesthetic practice. This paper focuses on the synthesis and functions of steroids and risks associated with their supplementation. This paper also highlights the recent trends, relevance, and consensus issues on the use of steroids as adjunct pharmacological agents in relation to anaesthetic practice and intensive care, along with emphasis on important clinical aspects of perioperative usefulness and supplementation.

Cushing's surgery: Role of the anesthesiologist

Cushing's syndrome is a clinical situation, caused by excessive glucocorticoid level, resulting in several features such as central obesity, supraclavicular fat, "moon face," "buffalo hump," hyperglycemia, metabolic alkalosis, hypokalemia, poor wound healing, easy bruising, hypertension, proximal muscle weakness, thin extremities, skin thinning, menstrual irregularities, and purple striae. In the perioperative period, the anesthesiologist must deal with difficult ventilation and intubation, hemodynamic disturbances, volume overload and hypokalemia, glucose intolerance, and diabetes, maintaining the blood cortisol level and preventing the glucocorticoid deficiency. This syndrome is quite rare and its features make these patients very difficult to the anesthesiologist.

Is Peri-Operative Isolated Systolic Hypertension (ISH) a Cardiac Risk Factor?

We are presenting a review of Isolated Systolic Hypertension (ISH) as a cardiovascular risk factor with emphasis on the perioperative period.

Isolated systolic hypertension is associated with aging and is the most frequent subtype (65%) among patients with uncontrolled hypertension. ISH is strongly associated with increased risks of cardiac and cerebrovascular events exceeding those in comparably aged individuals with diastolic hypertension. Patients with ISH show an increase in left ventricular (LV) mass and an increase in the prevalence of left ventricular hypertrophy (LVH). These LV changes increase cardiovascular events and frequently lead to diastolic dysfunction (DD). Treatment to reduce elevated systolic blood pressure has been shown to reduce the risk of cardiovascular events.

In the perioperative setting, essential hypertension has not been found to be a significant risk factor for cardiac complications. Most of the studies were based on the definition of essential hypertension and underpowered in sample size. The significance of perioperative ISH, however, is not well studied, partly due to its recognition only fairly recently as a cardiovascular risk factor in the non-surgical setting, and partly due to the evolving definition of ISH.

Perioperative cardiac complications remain a significant problem to the healthcare system and to the patient. Although the incidence of perioperative cardiac complications is prominent in high-risk patients as defined by the Revised Cardiac Risk Index (RCRI), the bulk of the cardiac complications actually occur in low-risk group. Currently, little understanding exists on the occurrence of perioperative cardiac complications in low- risk patients. A factor such as ISH, with its known pathophysiological changes, is a potential perioperative risk factor.

We believe ISH is an under-recognized perioperative risk factor and deserves further studying. Our research group has recently been funded by the Heart Stroke Foundation (HSF) to examine ISH as a perioperative risk factor (PROMISE Study).

Anti-Emetic Doses of Dexamethasone Suppress Cortisol Response in Laparoscopic Cholecystectomy

The efficacy of dexamethasone alone or in combination with a serotonergic antagonist to prevent nausea and vomiting in laparoscopic cholecystectomy is well established, but few data exist regarding its effects on perioperative cortisol and glucose levels.

Fourteen non-diabetic subjects having elective laparoscopic choleycystectomy and standardised general anaesthesia were randomised to receive 8 mg of intravenous dexamethasone and tropisetron or tropisetron alone. Plasma cortisol and glucose were measured preinduction, at five and 24 hours postoperatively. There was no difference in plasma cortisol at five hours postoperatively in patients who received dexamethasone, but by 24 hours there was marked suppression compared to the control group (P <0.005) to less than 5% of the preoperative value. There was a small but statistically significant elevation in blood glucose at 24 hours (P <0.01) in the dexamethasone-treated group.

In patients undergoing laparoscopic cholecystectomy, an anti-emetic dose of dexamethasone (8 mg) markedly suppresses plasma cortisol at 24 hours and causes a minor elevation in blood glucose.

The hemodynamic effects of CO2-induced pressure on the kidney in an isolated perfused rat kidney model

BACKGROUND

Variable mechanisms were suggested to mediate the changes in renal hemodynamics during pneumoperitoneum. To assess whether it can be pressure dependent only, we conduct a study in an isolated, pressurized, and perfused organ model.

METHODS

Seventy Wistar rat kidneys were perfused with oxygenated, 3% albumin-contained Krebs-Henseleit solution. Experiments took place within Plexiglass chamber that provided conditions for perfusion of organs, humidity, and maintenance of intracameral CO2 pressures [0 (control), 3, 5, 8, 12, 15, and 18 mm Hg]. All kidneys (10/group) were perfused for 60 minutes. One-half of the groups were perfused for an additional 30 minutes, during which the perfusion pressures were reduced to 0 mm Hg. pH of the perfusate was measured as well.

RESULTS

The perfusion pressure increased and the kidney flow decreased slightly, in proportion with the intrachamber pressure. Urine output decreased to a minimum of 40% in >or=8 mm Hg pressure conditions, compared with the control group. The pH values were below normal, during experimental pneumoperitoneum.

CONCLUSIONS

Pneumoperitoneal conditions are a direct cause of changes in renal urinary output. The increase in pCO2 pressure and consequently low intraorgan pH may contribute to a mild transient renal damage during pneumoperitoneum.

Management of disorders of sex development

Disorders of sex development comprise a group of diagnoses that represent significant and controversial management difficulties, such as those relating to gender assignment, genital surgery and risk of gonadal malignancy or future gender dysphoria. These issues arise on the background of a diagnosis that is often fraught with psychological trauma for patients and their families. There have been many changes in the medical approach to management in recent years; however, more research is required. This should focus on achieving accurate diagnosis in the first case, and on following outcomes to advise best practice. Finally, rational dialogue between multidisciplinary care providers, ethicists and patients and their families will only lead to improved care for these children.

Endocrine aspects of critical illness

Metabolic disorders and endocrine changes are common and relevant in critically ill patients. Thereby, endocrinopathies, electrolyte or metabolic derangements may either pre-exist or develop, and left unattended, may lead to significant morbidity and mortality. The homeostatic corrections which have emerged in the course of human evolution to cope with the catastrophic events during critical illness involve a complex multisystem endeavour, of which the endocrine contribution is an integral component. Although the repertoire of endocrine changes has been probed in some detail, discerning the vulnerabilities and failures of this system is far more challenging. The ensuing endocrine topics illustrate some of the current issues reflecting attempts to gain an improved insight and clinical outcome for critical illness. Disturbances in glucose and cortisol homeostasis during critical illness are two controversially debated topics in the current literature. The term "hormokine" encompasses the cytokine like behaviour of hormones during inflammation and infections. The concept is based on an ubiquitous expression of calcitonin peptides during sepsis. Adrenomedullin, another member of the calcitonin peptide superfamily, was shown to complement and improve the current prognostic assessment in lower respiratory tract infections. Procalcitonin is the protopye of "hormokine" mediators circulating procalcitonin levels increase several 10,000-fold during sepsis improve the clinical assessment especially of respiratory tract infections and sepsis safely and markedly reduces antibiotic usage in non-bacterial respiratory tract infections and meningitis. Adrenomedullin, another member of the calcitonin peptide superfamily, was shown to complement and improve the current prognostic assessment in lower respiratory tract infections. Hormokines are not only biomarkers of infection. Hormokines are also pivotal inflammatory mediators. Like all mediators, their role during systemic infections is basically beneficial, possibly to combat invading microbes. Yet, with increasing levels they can become harmful for their host. Multiple mechanisms of action were proposed. In several animal models the modulation and neutralization of hormokines during infection was shown to improve survival and thus might open new treatment options for severe infections, especially of the respiratory tract.

Helium gas pneumoperitoneum can improve the recovery of gastrointestinal motility after a laparoscopic operation

The use of laparoscopic surgery contributes to faster recovery of postoperative gastrointestinal motility. Several authors have demonstrated the benefits of laparoscopic surgery using carbon dioxide (CO2) pneumoperitoneum. However, there have been few investigations of the effects of other insufflation gases on gastrointestinal motility. The aim of this study was to investigate the effect of CO2 and helium pneumoperitoneum on the recovery of postoperative gastrointestinal motility. For this study, male Sprague-Dawley rats were divided into four groups: control, CO2 insufflation (10 mmHg), helium insufflation (10 mmHg) and open laparotomy for one hour. Arterial pH values and PaCO2 were measured after surgery. Gastrointestinal motility was evaluated by quantifying the distribution of markers placed into the stomach at the end of procedures until 24 hours after surgery. In the CO2 insufflation group, the arterial pH value was significantly lower than that of the helium insufflation group, and significant hypercapnia persisted until six hours after surgery. The gastric emptying and transit time was significantly prolonged in the CO2 group compared with the helium insufflation group. This study demonstrates that helium pneumoperitoneum can improve the recovery of postoperative gastrointestinal motility because of the reduction of hypercapnia and a tendency to suffer acidosis compared with CO2 pneumoperitoneum.

Measurement of serum free cortisol shows discordant responsivity to stress and dynamic evaluation

CONTEXT

Routinely available assays of adrenal function measure serum total cortisol (TC) and not the biologically active free cortisol (FC). However, there are few data on FC levels during surgical stress and in response to standard pharmacological tests.

OBJECTIVE

Our objective was to evaluate TC and FC levels in different states of physical stress.

DESIGN AND SETTING

We conducted a prospective observational study in a university hospital.

PARTICIPANTS AND MAIN OUTCOME MEASURES

We measured TC and FC levels in 64 patients: group A, 17 healthy controls without stress; group B, 23 medical patients with moderate stress; and group C, 24 surgical patients undergoing coronary bypass grafting. Cortisol levels in group C were measured basally and at several time points thereafter and were compared with responsivity to a pharmacological dose of ACTH. FC was measured using equilibrium dialysis.

RESULTS

In group C patients after extubation, the relative increase above basal FC was higher than the increase in TC levels (399 +/- 266 vs. 247 +/- 132% of initial values, respectively; mean +/- sd; P = 0.02) and then fell more markedly, FC levels falling to 67 +/- 49% and TC levels to 79 +/- 36% (P = 0.04). After ACTH stimulation, TC levels increased to 680 +/- 168 nmol/liter, which was similar to the increase with major stress (811 +/- 268 nmol/liter). In contrast, FC levels increased to 55 +/- 16 nmol/liter after ACTH stimulation but significantly greater with surgical stress to 108 +/- 56 nmol/liter (P < 0.001).

CONCLUSION

The more pronounced increase in FC seen during stress as compared with the ACTH test suggests that this test does not adequately anticipate the FC levels needed during severe stress.

The hypothalamic-pituitary-adrenal axis in critical illness

The hypothalamic-pituitary-adrenal response to stress is a dynamic process. The homeostatic corrections that have emerged in the course of human evolution to cope with the catastrophic events during critical illness involve a complex multisystem endeavor. Although the repertoire of endocrine changes has been probed in some detail, discerning the vulnerabilities and failures of this system is far more challenging. One of the most controversially debated topics in the current literature is the characterization and optimal treatment of allegedly inadequate adaptations of the hypothalamic-pituitary-adrenal axis during critical illness. This outline attempts to touch briefly some of the debated issues, stir the discussion, and thereby contribute to resolving the dispute.

Hypothalamic pituitary adrenal function during critical illness: limitations of current assessment methods

CONTEXT

Activation of the hypothalamic-pituitary-adrenal (HPA) axis represents one of several important responses to stressful events and critical illnesses. Despite a large volume of published data, several controversies continue to be debated, such as the definition of normal adrenal response, the concept of relative adrenal insufficiency, and the use of glucocorticoids in the setting of critical illness.

OBJECTIVES

The primary objective was to review some of the modulating factors and limitations of currently used methods of assessing HPA function during critical illness and provide alternative approaches in that setting.

DESIGN

This was a critical review of relevant data from the literature with inclusion of previously published as well as unpublished observations by the author. Data on HPA function during three different forms of critical illnesses were reviewed: experimental endotoxemia in healthy volunteers, the response to major surgical procedures in patients with normal HPA, and the spontaneous acute to subacute critical illnesses observed in patients treated in intensive care units.

SETTING

The study was conducted at an academic medical center.

PATIENTS/PARTICIPANTS

Participants were critically ill subjects.

INTERVENTION

There was no intervention.

MAIN OUTCOME MEASURE

The main measure was to provide data on the superiority of measuring serum free cortisol during critical illness as contrasted to those of total cortisol measurements.

RESULTS

Serum free cortisol measurement is the most reliable method to assess adrenal function in critically ill, hypoproteinemic patients. A random serum free cortisol is expected to be 1.8 microg/dl or more in most critically ill patients, irrespective of their serum binding proteins. Because the free cortisol assay is not currently available for routine clinical use, alternative approaches to estimate serum free cortisol can be used. These include calculated free cortisol (Coolens' method) and determining the free cortisol index (ratio of serum cortisol to transcortin concentrations). Preliminary data suggest that salivary cortisol measurements might be another alternative approach to estimating the free cortisol in the circulation. When serum binding proteins (albumin, transcortin) are near normal, measurements of total serum cortisol continue to provide reliable assessment of adrenal function in critically ill patients, in whom a random serum total cortisol would be expected to be 15 microg/dl or more in most patients. In hypoproteinemic critically ill subjects, a random serum total cortisol level is expected to be 9.5 microg/dl or more in most patients. Data on Cosyntropin-stimulated serum total and free cortisol levels should be interpreted with the understanding that the responses in critically ill subjects are higher than those of healthy ambulatory volunteers. The Cosyntropin-induced increment in serum total cortisol should not be used as a criterion for defining adrenal function, especially in critically ill patients.

CONCLUSIONS

The routine use of glucocorticoids during critical illness is not justified except in patients in whom adrenal insufficiency was properly diagnosed or others who are hypotensive, septic, and unresponsive to standard therapy. When glucocorticoids are used, hydrocortisone should be the drug of choice and should be given at the lowest dose and for the shortest duration possible. The hydrocortisone dose (50 mg every 6 h) that is mistakenly labeled as low-dose hydrocortisone leads to excessive elevation in serum cortisol to values severalfold greater than those achieved in patients with documented normal adrenal function. The latter data should call into question the current practice of using such doses of hydrocortisone even in the adrenally insufficient subjects.

Shorter PFA-100-closure times in laparoscopic versus conventional hysterectomy are not caused by increased vasopressin levels

BACKGROUND/OBJECTIVES

Bleeding problems during laparoscopic surgery are infrequent. We hypothesised that increased abdominal pressure during the application of the pneumoperitoneum would lead to an increased release of endogenous vasopressin which could then contribute to the hemostasis by increasing platelet reactivity, FVIII and von Willebrand-factor.

PATIENTS AND METHODS

We compared the vasopressin levels, the platelet function as measured by the PFA-100-test, aPTT and FVIII in 39 consecutive patients who underwent elective hysterectomy (20 with the laparoscopic and 19 with the conventional, "open" method). Blood was sampled the day before surgery and 2, 4 and 72 h after the induction of anaesthesia.

RESULTS

After two hours, the PFA-100 closure times with collagen/ADP decreased to lower levels in the laparoscopic group (from 93 +/- 22 to 82 +/- 20, mean +/- SD) and even further down to 65 +/- 13 s (compared to 82 +/- 20 s) (p = 0.024)) four hours after the beginning of surgery. Vasopressin levels and F VIII increased in both groups but there was no significant difference between the groups (21 vs. 17.8 pmol/l for vasopressin, differences of the mean). Bleeding was minimal, with a trend to lower Hb-levels in the laparotomy group.

CONCLUSIONS

The procedural difference of laparoscopic vs. open hysterectomy appears to enhance platelet reactivity by other mechanisms than increased vasopressin levels and may contribute to an enhanced hemostatic competence in laparoscopic surgery.

Management of adrenal insufficiency in different clinical settings

Adrenal insufficiency is a rare disease, but its prevalence is increasing. The most frequent cause of primary adrenal insufficiency in western countries is autoimmune adrenalitis, whereas secondary adrenal insufficiency is most often caused by pituitary tumours and their treatment (e.g., surgery). Chronic glucocorticoid replacement consists of hydrocortisone 15-25 mg/day in divided doses and dose monitoring is largely based on clinical judgement. Fludrocortisone 0.05-0.2 mg/day is given for substitution in mineralocorticoid deficiency aiming at normotension, normokalaemia and a plasma renin activity in the upper normal range. It has recently been shown that, despite adequate glucocorticoid and mineralocorticoid replacement well being in patients with adrenal insufficiency is still impaired. Several studies have demonstrated that dehydroepiandosterone 25-50 mg/day p.o. may improve mood, fatigue, well-being and, in women, also sexuality, suggesting that dehydroepiandosterone should become part of the standard treatment regime. However, large Phase III trials of dehydroepiandosterone for adrenal insufficiency are still lacking and it has not yet been approved for the treatment of this disease. Patients with adrenal insufficiency are at risk of adrenal crisis, usually precipitated by major stress, such as severe infection or surgery. Early dose adjustments are required to cover the increased glucocorticoid demand in stress. Careful and repeated education of patients and their partners is the best strategy to avoid this life-threatening emergency. Some recent studies suggest that during sepsis some patients with intact adrenal function may develop transient relative adrenal insufficiency and benefit from administration of hydrocortisone plus fludrocortisone. However, the pathophysiology and diagnosis criteria of relative adrenal insufficiency and its treatment remain unsettled issues.

Potential prophylactic measures against postoperative immunosuppression: could they reduce recurrence rates in oncological patients?

BACKGROUND

Removing the primary tumor is indispensable for eliminating the major pool of metastasizing cells, but the surgical procedure itself is suspected of promoting metastases. This adverse effect is attributed to several mechanisms acting in synergy, including mechanical release of tumor cells, enhanced angiogenesis, secretion of growth factors, and immunosuppression. Here we provide new insights into mechanisms of postoperative immunosuppression and assess the assumptions underlying the hypothesis that, by suppressing cell-mediated immunity (CMI), surgery may render the patient vulnerable to metastases that otherwise could have been controlled.

METHODS

An extensive review of relevant articles in English identified by using the MEDLINE database and cross-referencing.

RESULTS

Current literature suggests that (1) CMI can control minimal residual disease, especially if surgery is performed early; (2) major surgery transiently but markedly suppresses CMI through multiple mechanisms now better understood; (3) surgical stress promotes experimental metastasis through immunosuppression, but the clinical evidence remains indirect because of ethical limitations.

CONCLUSIONS

Minimizing postoperative immunosuppression seems feasible, may limit recurrence, and should be introduced into the broader array of considerations when planning oncological surgeries. In the short run, physicians could try to avoid immunosuppressive anesthetic approaches, inadvertent hypothermia, excessive blood transfusions, and untended postoperative pain. When feasible, minimally invasive surgery should be considered. In the long run, clinical trials should evaluate prophylactic measures, including perioperative immunostimulation and several antagonists to cytokines and hormones specified herein.

Catecholamine release during laparoscopic fundoplication with high and low doses of remifentanil

BACKGROUND

Reports on stress responses to laparoscopic surgery have been conflicting. Depth of anesthesia may influence the neuro-hormonal release, including catecholamines. Opioids depress general sympathetic activation in a dose-dependent manner. We investigated the hypothesis that remifentanil would depress the catecholamine response to pneumoperitoneum and laparoscopic surgery differently with a high dose (HD) compared with a low dose (LD).

METHODS

In a randomized, prospective study we investigated 18 ASA I-II patients undergoing laparoscopic fundoplication with an intra-abdominal pressure of 12 mmHg. The patients were randomized to receive either a LD (0.13 microg kg-1x min-1) or HD (0.39 microg kg-1 x min-1) of remifentanil with a target-controlled infusion (TCI) technique. Bispectral index of EEG (BIS) was maintained at 40-55 by propofol delivered by a TCI system. Arterial catecholamines were analyzed at different times during the procedure.

RESULTS

Norepinephrine increased equally in both groups during pneumoperitoneum and surgical intervention. Epinephrine stayed low in the HD-group, while increasing during surgery in the LD-group.

CONCLUSION

High dose of remifentanil depressed the epinephrine response to pneumoperitoneum and surgery, indicating no general activation of the sympathetic nervous system. Neither a LD nor HD of remifentanil depressed the norepinephrine response during pneumoperitoneum. This suggests a centrally independent release of norepinephrine.

Adrenal insufficiency in the critically ill: a new look at an old problem

Stress from many sources, including pain, fever, and hypotension, activates the hypothalamic-pituitary-adrenal (HPA) axis with the sustained secretion of corticotropin and cortisol. Increased glucocorticoid action is an essential component of the stress response, and even minor degrees of adrenal insufficiency can be fatal in the stressed host. HPA dysfunction is a common and underdiagnosed disorder in the critically ill. We review the risk factors, pathophysiology, diagnostic approach, and management of HPA dysfunction in the critically ill.

Effect of prolonged pneumoperitoneum on intraoperative urine output during laparoscopic gastric bypass

BACKGROUND

Intraoperative oliguria is common during laparoscopic operations. The objective of this study was to evaluate the effects of prolonged pneumoperitoneum during laparoscopic gastric bypass (GBP) on intraoperative urine output and renal function.

METHODS

104 patients with a body mass index between 40 and 60 kg/m2 were randomly assigned to laparoscopic (n = 54) or open (n = 50) GBP. Intraoperative urine output was recorded at 30-min intervals. Blood urea nitrogen and creatinine levels were measured at baseline and on postoperative days 1, 2, and 3. Levels of antidiuretic hormone, aldosterone, and plasma renin activity were also measured in a subset of laparoscopic (n = 22) and open (n = 24) GBP patients at baseline, 2 hours after surgical incision, and in the recovery room.

RESULTS

The laparoscopic and open groups were similar in age, gender, and body mass index. There was no significant difference in amount of intraoperative fluid administered between groups (5.4 +/- 1.6 L, laparoscopic versus 5.8 +/- 1.7 L, open), but operative time was longer in the laparoscopic group (232 min versus 200 min, p < 0.01). Urinary output during laparoscopic GBP was 64% lower than during open GBP at 1 hour after surgical incision (19 mL versus 55 mL, p < 0.01) and continued to remain lower than that of the open group by 31-50% throughout the operation. Postoperative blood urea nitrogen and creatinine levels remained within the normal range in both groups. Serum levels of antidiuretic hormone, aldosterone, and plasma renin activity peaked at 2 hours after surgical incision with no significant difference between the two groups.

CONCLUSION

Prolonged pneumoperitoneum during laparoscopic gastric bypass significantly reduced intraoperative urine output but did not adversely alter postoperative renal function.

Adrenal insufficiency in critically ill patients with human immunodeficiency virus

OBJECTIVE

The adrenal gland is the endocrine organ most commonly involved in patients infected with human immunodeficiency virus (HIV). It is important to recognize patients with adrenal insufficiency, because this disorder may be fatal if untreated. The incidence of adrenal insufficiency in critically ill HIV-infected patients is unclear, partly because different criteria are used to diagnose adrenal insufficiency. To help clarify the incidence of adrenal insufficiency in HIV-infected critically ill patients, we compared the incidence based on the stress cortisol concentration, low-dose corticotropin stimulation test, and high-dose corticotropin stimulation test.

SETTING

Medical intensive care unit.

PATIENTS

Twenty-eight critically ill patients with HIV, mean age 43 +/- 9 years; 20 were male; 54% died.

INTERVENTIONS

We performed a 1-microg (low-dose adrenocorticotropic hormone; LD-ACTH) and 249 microg (high-dose; HD-ACTH) corticotropin stimulation test in HIV-infected critically ill patients not receiving corticosteroids. According to results of the stress serum cortisol concentration and LD-ACTH and HD-ACTH tests, patients were classified as having adrenal insufficiency or as normal. The results of newly revised diagnostic criteria for adrenal insufficiency (i.e., stress cortisol concentration and cortisol response to LD-ACTH <25 microg/dL) were compared with the traditional criteria (i.e., stress cortisol level and response to HD-ACTH <18 microg/dL). In addition, the associations between adrenal insufficiency and the CD4 count, human cytomegalovirus antigenemia, and other risk factors for adrenal insufficiency were determined.

MEASUREMENTS AND MAIN RESULTS

When we used a stress cortisol concentration <18 microg/dL as the sole diagnostic threshold for diagnosis of adrenal insufficiency, 50% (14 of 28) of patients had adrenal insufficiency. The incidence was 75% (21 of 28) when we used a diagnostic threshold of <25 microg/dL for the stress cortisol concentration. When we used both the stress cortisol concentration and LD-ACTH test with a diagnostic cortisol threshold concentration <18 microg/dL, 21% (six of 28) had adrenal insufficiency. The incidence was 46% (13 of 28) when we used a cortisol diagnostic threshold concentration of <25 microg/dL. When we used both the stress cortisol concentration and the HD-ACTH stimulation test with a diagnostic cortisol threshold of <18 microg/dL, 7% (two of 28) had adrenal insufficiency. The incidence of adrenal insufficiency was 21% (six of 28) with a cortisol diagnostic threshold value of <25 microg/dL. Human cytomegalovirus antigenemia was the only variable assessed that was associated with adrenal insufficiency.

CONCLUSION

There is a high incidence of adrenal insufficiency in critically ill HIV-infected patients that varies with the criteria used to diagnose adrenal insufficiency. The LD-ACTH stimulation test is more sensitive than the high-dose test for diagnosing adrenal insufficiency in this population. Because of the high incidence of inadequate adrenal function, all critically ill HIV-infected patients should undergo an evaluation for adrenal insufficiency with the stress cortisol concentration and LD-ACTH stimulation tests.

Preserved CO(2) reactivity and increase in middle cerebral arterial blood flow velocity during laparoscopic surgery in children

In adult patients, the creation of pneumoperitoneum (PP) by means of carbon dioxide (CO(2)) insufflation leads to an increase in cerebral blood flow velocity (CBFV), which is thought to be caused by hypercapnia. We evaluated whether PP leads to an increase of CBFV in children, and whether this increase is directly related to PP. The effects of PP on middle cerebral artery blood flow velocity were investigated in 12 children (mean age 3 yr, range 15-63 mo) undergoing laparoscopic herniorrhaphy under general anesthesia with sevoflurane and nitrous oxide/oxygen. CBFV was measured by using transcranial Doppler ultrasonography. During CO(2) insufflation, the end-tidal CO(2) concentration was kept constant by adjustment of ventilation by increasing minute volume. The CBFV increased significantly at an intraabdominal pressure of 12 mm Hg compared with baseline from 68 +/- 11 cm/s to 81 +/- 12 cm/s (P < 0.05). CO(2) reactivity remained in the normal range (4.0% +/- 1.9%/mm Hg) during PP. We conclude that the induction of PP leads to an increase in middle cerebral artery blood flow velocity in young children independent from hypercapnia, whereas CO(2) reactivity remains normal.

IMPLICATIONS

Laparoscopic surgery is performed frequently in pediatric patients. Cerebral blood flow velocities increase during insufflation of the intraperitoneal cavity for minimally invasive surgery in children. The vasoreactivity as part of the cerebral autoregulation remains unaffected.

The utility of plasma CRH as a predictor of preterm delivery

It has been suggested that CRH is a placental clock that controls the duration of pregnancy and that the timing of the rise in CRH may permit prediction of the onset of labor. We have performed a prospective longitudinal study, in 297 women, to examine the utility of a single second-trimester plasma CRH measurement to predict preterm delivery. Venous blood samples were taken at 4-weekly intervals, beginning at 16-20 wk gestation, until delivery for CRH and its binding protein. A time point at which a single plasma CRH test might give optimal data to predict preterm delivery was determined. Thirty-one subjects delivered prematurely (10.4%). Sampling for plasma CRH at 26 wk gestation seemed the optimal time point to maximize sensitivity and specificity of the test. The mean (+/- SD) plasma CRH in women at this gestation who eventually delivered after spontaneous labor within 1 wk of their due date (39-41 wk, n = 127) was 34.7 +/- 27.0 pM. A plasma CRH of more than 90 pM at 26 wk gestation had a sensitivity of 45% and a specificity of 94% for prediction of preterm delivery. The positive predictive value was 46.7%. Calculation of free CRH did not improve these figures. In conclusion, a single measurement of plasma CRH, toward the end of the second trimester, may identify a group at risk for preterm delivery, but over 50% of such deliveries will be unpredicted. These data do not support the routine clinical use of plasma CRH as a predictor of preterm labor.

Hypothalamic-pituitary-adrenal insufficiency

Adrenal insufficiency is a common and underdiagnosed disorder that develops in critically ill patients. Most forms are acquired and will resolve with treatment of the underlying disease. Hypotension that is refractory to fluids and requires vasopressors is the most common presentation of adrenal insufficiency in the ICU. It is important to make the diagnosis of adrenal insufficiency, because current data suggest that treatment with glucocorticoids improves outcome. Diagnosis usually can be made on the basis of a stress cortisol level. Occasionally, when the level of stress is uncertain, the low-dose corticotropin stimulation test will be required for definitive diagnosis. A therapeutic trial with hydrocortisone should be started in patients with suspected adrenal insufficiency pending results of diagnostic testing.

Stress responses during laparoscopy with CO2 insufflation and with mechanical elevation of the abdominal wall

STUDY OBJECTIVE

To compare the intensity of stress responses caused by laparoscopy combined with CO2 insufflation (CI) with those caused by mechanical elevation of the abdominal wall (MEA).

DESIGN

Prospective study (Canadian Task Force classification I).

SETTING

Tertiary care university hospital.

PATIENTS

Thirty-one women. Intervention. Laparoscopy, 16 with CI and 15 with MEA.

MEASUREMENTS AND MAIN RESULTS

Circulating levels of norepinephrine, epinephrine, cortisol, and interleukin (IL)-6 were compared in the two groups. Arterial partial pressure of CO2 (PaCO2) did not increase during laparoscopy by either method. Plasma norepinephrine and epinephrine levels increased after extubation in the MEA group but not in the CI group. Circulating cortisol levels in both groups increased during laparoscopy; mean intraoperative levels were higher in the CI group. Serum IL-6 levels increased after extubation in the MEA but not the CI group. Mean heart rate increased during laparoscopy in both groups, whereas blood pressure increased only in the CI group. More patients in the MEA group required postoperative analgesia.

CONCLUSION

Laparoscopy with MEA caused more pronounced adrenosympathetic and cytokine responses than that with CI when PaCO2 was maintained within the range of normocapnia.

Plasma catecholamine responses during laparoscopic gynecologic surgery with CO(2) insufflation

STUDY OBJECTIVE

To compare adrenergic-sympathetic responses during pelvic laparoscopic surgery with CO(2) insufflation with those during laparotomy. DESIGN. Prospective study (Canadian Task Force classification II-1).

SETTING

Tertiary care university hospital.

PATIENTS

Twenty-one infertile women with a clinical diagnosis of endometriosis.

INTERVENTION

Plasma norepinephrine (NE) and epinephrine (E) levels were measured in patients undergoing laparoscopic or open pelvic surgery.

MEASUREMENTS AND MAIN RESULTS

During laparoscopic surgery, increases in NE and E levels were correlated with arterial tension of CO(2) (PaCO(2)) and were greater in patients with a larger increase in PaCO(2) than in those undergoing laparotomy. Hemodynamic changes were also more evident during laparoscopic surgery, with larger PaCO(2) increases.

CONCLUSION

The PaCO(2) increases due to CO(2) insufflation are associated with adrenergic-sympathetic activation and hemodynamic changes during laparoscopic pelvic surgery.

The relationship among carbon dioxide pneumoperitoneum, vasopressin release, and hemodynamic changes

We assessed the role of vasopressin (VP) for the hemodynamic response to pneumoperitoneum in pigs. Four groups of anesthetized pigs were investigated. Nine pigs were intraabdominally insufflated with CO2 and eight were intraabdominally insufflated with argon; eight pigs received an i.v. injection of 1 mg/kg SR 49059, a VP antagonist, before CO2 insufflation; and six pigs received SR 49059 alone. Hemodynamics, plasma concentrations of VP and vasoactive hormones, and Paco2 were measured. Data were analyzed by using analysis of variance, Student's t-test, and Mann-Whitney U-test. Five minutes after insufflation, changes in systemic vascular resistance (SVR) were significantly correlated with changes in VP (r = 0.72; P = 0.005) but not with changes in epinephrine, norepinephrine, renin activity, or Paco2. SVR increased during CO2 insufflation but not during argon insufflation or CO2 insufflation with a preceding infusion of SR 49059. The SR 49059 injection itself resulted in increases in heart rate and cardiac output and decreases in blood pressure and SVR. We conclude that, during CO2 pneumoperitoneum in pigs, absorbed CO2 initiates a pathophysiological process that stimulates VP release. Hence, VP most likely plays a key role in the hemodynamic response to a CO2-induced pneumoperitoneum.

IMPLICATIONS

Intraabdominal insufflation of CO2 is associated with hemodynamic and hormonal changes. Investigating CO2 and argon-insufflated pigs and using a vasopressin antagonist, we found that CO2 insufflation released vasopressin, which, in turn, induced hemodynamic perturbances.

Abdominal wall lift versus carbon dioxide insufflation for laparoscopic resection of ovarian tumors

STUDY OBJECTIVE

To evaluate and compare changes in pulmonary mechanics and stress hormone responses between abdominal wall lift (gasless) and carbon dioxide (CO2) insufflation laparoscopic surgery during controlled general anesthesia.

DESIGN

Prospective, randomized clinical study.

SETTING

Operating rooms at a university medical center.

PATIENTS

12 ASA physical status I and II female patients undergoing laparoscopic resection of ovarian tumors.

INTERVENTIONS

Patients were divided into two groups of six each: the abdominal wall lift group and the CO2 pneumoperitoneum laparoscopic group. Following induction of anesthesia, patients were paralyzed and the trachea was intubated. Anesthesia was maintained with isoflurane and nitrous oxide (N2O) in oxygen. Throughout the procedure, patients were mechanically ventilated with a tidal volume of 10 ml/kg and a respiratory rate of 10 breaths per minute.

MEASUREMENTS AND MAIN RESULTS

During the laparoscopic procedure, arterial blood gases, acid-base balance, pulmonary mechanics, stress-related hormones, and urine output were measured and recorded. In the CO2 pneumoperitoneum group, arterial CO2 tension increased (p < 0.01), dynamic pulmonary compliance decreased (p < 0.01), peak inspiratory airway pressure increased (p < 0.01), and plasma epinephrine (p < 0.05), norepinephrine (p < 0.05), dopamine (p < 0.01), and antidiuretic hormones (p < 0.05) increased significantly during the laparoscopic procedure as compared to the abdominal lift group. Adrenocorticotropic hormone and cortisol increased as compared to baseline value in both groups (p < 0.05). Urine output was significantly less (p < 0.01) in the CO2 pneumoperitoneum group than in the abdominal wall lift group.

CONCLUSIONS

Abdominal wall lift laparoscopic surgery is physiologically superior to CO2 pneumoperitoneum laparoscopic surgery as seen during the conditions of this study. Abdominal wall lift laparoscopic surgery provides normal acid-base balance and a lesser degree of hormonal stress responses, it maintains urine output, and it avoids derangement of pulmonary mechanics.