Tomas Corcoran

Perioperative fluid management strategies in major surgery: a stratified meta-analysis

BACKGROUND: Both “liberal” and “goal-directed” (GD) therapy use a large amount of perioperative fluid, but they appear to have very different effects on perioperative outcomes. We sought to determine whether one fluid management strategy was superior to the others. METHODS: We selected randomized controlled trials (RCTs) on the use of GD or restrictive versus liberal fluid therapy (LVR) in major adult surgery from MEDLINE, EMBASE, PubMed (1951 to April 2011), and Cochrane controlled trials register without language restrictions. Indirect comparison between the GD and LVR strata was performed. RESULTS: A total of 3861 patients from 23 GD RCTs (median sample size = 90, interquartile range [IQR] 57 to 109) and 1160 patients from 12 LVR RCTs (median sample size = 80, IQR36 to 151) were considered. Both liberal and GD therapy used more fluid compared to their respective comparative arm, but their effects on outcomes were very different. Patients in the liberal group of the LVR stratum had a higher risk of pneumonia (risk ratio [RR] 2.2, 95% confidence interval [CI] 1.0 to 4.5), pulmonary edema (RR 3.8, 95% CI 1.1 to 13), and a longer hospital stay than those in the restrictive group (mean difference [MD] 2 days, 95% CI 0.5 to 3.4). Using GD therapy also resulted in a lower risk of pneumonia (RR 0.7, 95% CI 0.6 to 0.9) and renal complications (0.7, 95% CI 0.5 to 0.9), and a shorter length of hospital stay (MD 2 days, 95% CI 1 to 3) compared to not using GD therapy. Liberal fluid therapy was associated with an increased length of hospital stay (4 days, 95% CI 3.4 to 4.4), time to first bowel movement (2 days, 95% CI 1.3 to 2.3), and risk of pneumonia (RR ratio 3, 95% CI 1.8 to 4.8) compared to GD therapy. CONCLUSION: Perioperative outcomes favored a GD therapy rather than liberal fluid therapy without hemodynamic goals. Whether GD therapy is superior to a restrictive fluid strategy remains uncertain.

The Retrospective Application of a Prediction Model to Patients Who Have Had a Decompressive Craniectomy for Trauma

There is currently a resurgence of interest in the use of decompressive craniectomy. As the procedure is used more frequently, there may be an increasing number of patients surviving a severe traumatic brain injury with severe neurological impairment. The aim of this study was to determine if we could predict those cases that fall into this category. We used the web-based prediction model prepared by the CRASH collaborators and applied it to a cohort of patients who had a decompressive craniectomy in 2006 and 2007 at the two major trauma hospitals in Western Australia. All clinical and radiological data were reviewed and entered into the model, and predicted outcome and actual outcome were compared. Our analysis indicated that a significant cut-off point appeared at which the model predicted a 75% risk of an unfavorable outcome at 6 months; 19 of 27 patients with CRASH scores <75% returned to work, whereas none of the 14 patients with higher scores achieved this degree of rehabilitation at 18 months. Statistical analysis of the outcomes in our cohort confirmed that the CRASH model reliably predicted unfavorable outcome. This study demonstrated that our ability to predict poor outcome has improved.

The quality of Internet-sourced information for patients with chronic pain is poor

BackgroundThe Internet is an increasingly popular information resource for patients. Patients with chronic pain are a subsection of the community who are likely to seek information about their condition, but previously little was known about the quality of information they may encounter during an Internet search. AimsThe aims of this study were to develop and validate a scoring system for assessing chronic pain websites and then use this to determine the quality of chronic pain information on the Internet, which a patient employing typical “surfer” behavior might encounter. MethodsA scoring system for assessing chronic pain websites was designed and validated. It comprised quality (design features) and technical (information) accuracy scores. Validity was assessed by intraclass correlation coefficients. The search term “chronic pain” was used on 5 popular search engines to identify websites. Only the first 10 sites retrieved were scored. ResultsThere were 23 websites duplicated across the search engines, leaving a total of 27 websites to be scored. The majority of websites were rated as either poor or fair across the 2 individual scores and the grand score. Two websites had a grand score classified as either very good or excellent. ConclusionsAlthough we cannot determine whether patients accurately interpret the quality of websites, our study confirms that good quality information about chronic pain is unlikely to be retrieved by our patients on the Internet.

Perioperative management of clopidogrel therapy: the effects on in-hospital cardiac morbidity in older patients with hip fractures

BACKGROUND Increasing numbers of older patients prescribed clopidogrel are presenting for urgent hip fracture surgery. Best practice for the management of clopidogrel therapy is unknown, although delays to surgery are associated with increased mortality. We investigated the influence of perioperative management of clopidogrel therapy on in-hospital cardiac morbidity and transfusion in this population. METHODS Retrospective review of all patients aged >60 yr, admitted to a single centre with hip fractures between June 2005 and November 2008. Acute coronary syndrome (ACS) was defined as a raised plasma troponin concentration >0.04 µg litre(-1) associated with chest pain, new ECG changes, or both. RESULTS Of 1381 patients admitted with hip fractures, 114 were receiving regular clopidogrel therapy with a median age of 83.7 (60-98) yr. Clopidogrel was withheld perioperatively in 111 (98%) of these patients. Twenty-three patients (20.2%) suffered an ACS. Risk peaked for ACS [odds ratio (OR) 6.7 (95% confidence interval, CI, 1.7-25.8)] (P=0.006) between days 4 and 8 after clopidogrel withdrawal. The OR for requiring a blood transfusion during or after surgery peaked at day 1 after clopidogrel withdrawal [OR 2.31 (95% CI, 1.02-5.21)] (P=0.044). CONCLUSIONS The length of withdrawal of clopidogrel therapy perioperatively was associated with a significantly increased incidence of ACS. An association between shorter withdrawal and increased blood transfusion requirements was also seen. The study emphasizes the cardiovascular risks of routinely interrupting clopidogrel therapy in this at-risk population and that a more considered, individualized, evidenced-based approach is needed.

Are isofurans and neuroprostanes increased after subarachnoid hemorrhage and traumatic brain injury

Current diagnostic tools to assess neurological injury after aneurysmal subarachnoid hemorrhage (aSAH) and traumatic brain injury (TBI) have poor discriminatory abilities. Free radicals are associated with the pathophysiology of secondary damage after brain trauma. We examined cerebrospinal fluid (CSF) lipid markers of oxidative stress, isofurans (IsoFs), F(4)-neuroprostanes (F(4)-NeuroPs), and F(2)-isoprostanes (F(2)-IsoPs), in two case-controlled studies in patients with aSAH or severe TBI. Patients with aSAH (n=18) or TBI (n=18) were age and gender matched with separate control groups. CSF samples were collected from patients within 24 h of the injury. CSF IsoFs and F(4)-NeuroPs were increased in aSAH patients compared with their controls. In TBI patients, IsoFs and F(4)-NeuroPs were increased compared with their controls. F(2)-IsoPs were increased in aSAH patients, but not in TBI patients, compared with their respective controls. CSF IsoFs and F(4)-NeuroPs are consistently increased after a catastrophic central nervous system injury. These results suggest their measurement may enhance the management of unconscious patients in neurological care.

A Pilot Study for a Prospective, Randomized, Double-blind Trial of the Influence of Anesthetic Depth on Long-term Outcome

BACKGROUND:Deep general anesthesia has been associated with increased mortality in 5 observational studies. The association may be causal or an epiphenomenon due to increased anesthetic sensitivity in high-risk patients. We conducted a pilot study to assess the feasibility of performing a definitive randomized controlled trial. The aims of the study were to determine whether anesthetic depth targeting in a high-risk group was feasible and to document anesthetic doses and arterial blood pressures associated with “deep” and “light” general anesthesia. METHODS:ASA physical status III and IV patients, aged ≥60 years, having surgery lasting ≥2 hours, with expected hospital stay ≥2 days, and receiving general anesthesia were randomly allocated to a Bispectral Index (BIS) or spectral entropy (SE) target of 35 (“low” group) or 50 (“high” group). The primary end point was mean BIS or SE. Secondary end points were postanesthesia care unit length of stay and pain scores, quality of recovery score, hospital length of stay, postoperative complications, and death. A composite end point of postoperative complications (pneumonia, myocardial infarction, stroke, pulmonary embolism, heart failure, and death) was determined at 1 year. RESULTS:One hundred twenty-five patients were recruited. The mean of the median BIS/SE values for each patient during the maintenance phase of anesthesia in the low and high groups was significantly different: 39 vs 48 (mean difference 8 [95% confidence interval {CI95}, 6 to 10], P < 0.001). There was also a significant difference in mean volatile anesthetic administration (minimum alveolar concentration): 0.98 vs 0.64 (mean difference −0.35 [CI95, −0.44 to −0.26], P < 0.001) and target propofol concentrations: 4.0 vs 3.1 &mgr;g/mL (mean difference −0.8 [CI95, −1.2 to −0.3], P = 0.004). Intraoperative mean arterial blood pressures were similar (85 vs 87 mm Hg; mean difference 2 [CI95, −2 to 6], P = 0.86), and there were no differences in short-term recovery characteristics or hospital length of stay. There was a significant difference in the incidence of wound infection at 30 days (13% vs 3%; risk difference −10% [CI95, −21 to −0.1], P = 0.04). At 1 year, the composite rates of complications in the low and high groups were 28% and 17% (risk difference −11 [CI95, −25 to 4], P = 0.15) and mortality rates were 12% and 9%, respectively (risk difference −2 [CI95, −14 to 9], P = 0.70). CONCLUSIONS:This pilot study demonstrated that depth of anesthesia targeting with BIS or SE was achievable in a high-risk population with adequate separation of processed electroencephalogram monitor targets. The expected incidence of postoperative complications and mortality occurred. We conclude that a large, multicenter, randomized controlled trial is feasible.

Effects of spinal or general anesthesia on F2-isoprostanes and isofurans during ischemia/reperfusion of the leg in patients undergoing knee replacement surgery

General and spinal anesthesia are used extensively in orthopedic surgery. However, these methods of anesthesia may result in different amounts of oxygen being delivered to the patient. Ischemia/reperfusion injury after release of the tourniquet initiates free radical-mediated oxidative stress. F₂-isoprostanes are reliable markers of in vivo lipid peroxidation. However, under conditions of high oxygen tension, isofurans are formed. We aimed to compare plasma isofurans and F₂-isoprostanes in spinal versus general anesthesia in patients undergoing knee-replacement surgery in a randomized, blinded study. Thirty-nine patients were randomized to spinal (SA; n = 19) or general anesthesia (GA; n = 20). Blood was collected before anesthesia, and a tourniquet was then applied to the limb during surgery. After release of the tourniquet, blood samples were collected at 30 min, 2 h, and 24 h for measurement of plasma F₂-isoprostanes and isofurans by gas chromatography-mass spectrometry. The two groups were comparable in age and body mass index. Plasma F₂-isoprostanes were significantly lower in the GA patients compared with the SA patients (p = 0.045). In contrast, the GA patients had significantly elevated plasma isofurans (p = 0.032). Increased isofurans during GA compared with SA are likely to reflect increased oxidative stress due to elevated oxygen concentrations during GA. Further studies are required to assess the implications of these findings on perioperative outcomes.

Safety of Perioperative Glucocorticoids in Elective Noncardiac Surgery: A Systematic Review and Meta-analysis

Background: Glucocorticoids are increasingly used perioperatively, principally to prevent nausea and vomiting. Safety concerns focus on the potential for hyperglycemia and increased infection. The authors hypothesized that glucocorticoids predispose to such adverse outcomes in a dose-dependent fashion after elective noncardiac surgery. Methods: The authors conducted a systematic literature search of the major medical databases from their inception to April 2016. Randomized glucocorticoid trials in adults specifically reporting on a safety outcome were included and meta-analyzed with Peto odds ratio method or the quality effects model. Subanalyses were performed according to a dexamethasone dose equivalent of low (less than 8 mg), medium (8 to 16 mg), and high (more than 16 mg). The primary endpoints of any wound infection and peak perioperative glucose concentrations were subject to meta-regression. Results: Fifty-six trials from 18 countries were identified, predominantly assessing dexamethasone. Glucocorticoids did not impact on any wound infection (odds ratio, 0.8; 95% CI, 0.6 to 1.2) but did result in a clinically unimportant increase in peak perioperative glucose concentration (weighted mean difference, 20.0 mg/dl; CI, 11.4 to 28.6; P < 0.001 or 1.1 mM; CI, 0.6 to 1.6). Glucocorticoids reduced peak postoperative C-reactive protein concentrations (weighted mean difference, −22.1 mg/l; CI, −31.7 to −12.5; P < 0.001), but other adverse outcomes and length of stay were unchanged. No dose–effect relationships were apparent. Conclusions: The evidence at present does not highlight any safety concerns with respect to the use of perioperative glucocorticoids and subsequent infection, hyperglycemia, or other adverse outcomes. Nevertheless, collated trials lacked sufficient surveillance and power to detect clinically important differences in complications such as wound infection.

Is there a role for isofurans and neuroprostanes in pre-eclampsia and normal pregnancy?

Pre-eclampsia is a complex disorder of pregnancy that adversely affects the mother and baby. Arachidonic acid and docosahexaenoic acid are essential for fetal development and can undergo free radical oxidation to F(2)-isoprostanes (F(2)-IsoPs) and isofurans (IsoFs); and F(4)-neuroprostanes (F(4)-NeuroPs), respectively. These metabolites may be relevant to pre-eclampsia and fetal development. We examined IsoFs, F(4)-NeuroPs, and F(2)-IsoPs in maternal plasma and cord blood plasma of 23 women with pre-eclampsia and 21 normal pregnancies. Women with pre-eclampsia had significantly elevated maternal IsoFs and F(4)-NeuroPs, but not F(2)-IsoPs. Cord blood F(4)-NeuroPs were elevated among neonates of women with pre-eclampsia. In women with pre-eclampsia, birth weight was predicted by gestation at delivery. The latter was also true in normal pregnancy, but birth weight was negatively related to maternal F(2)-IsoPs, IsoFs, and F(4)-NeuroPs. We have shown that in women with pre-eclampsia, IsoFs and F(4)-NeuroPs are elevated, and cord blood F(4)-NeuroPs are increased. The inverse relationship between maternal F(2)-IsoPs, IsoFs, and F(4)-NeuroPs and birth weight may be relevant as predictors of low birth weight in normal pregnancy. Future studies should examine whether these markers in maternal blood at early stages of pregnancy relate to subsequent maternal, fetal, and neonatal complications.

A survey of patients' use of the internet for chronic pain-related information.

OBJECTIVE To investigate the use of the Internet as a pain information seeking tool among a population of patients attending a chronic pain clinic. METHODS A bespoke self-completing questionnaire was given to 150 patients attending 17 consecutive chronic pain clinics at The Royal Perth Hospital during August and September 2007. RESULTS One hundred twenty-two completed surveys were received, a response rate of 81%. Only 23.8% of the patients had used the Internet to access pain-related health care information. There was no gender difference between those who did and did not access the Internet for information. Age group, highest educational level attained, and the availability of Internet access were all significantly associated with the use of the Internet to search for pain-related information. 41.4% described the information they found as useful, 6.9% found it frightening and 10.3% found it confusing. Forty-four percent wanted more information to be available on the Internet while only 6.9% planned to discuss their findings with their doctor. CONCLUSIONS When compared with other studies about patient information-seeking behavior, a smaller than expected percentage of patients attending chronic pain clinics in Perth used the Internet to search for information about pain. There are a variety of reasons for this that would suggest that health care professionals should not be complacent but seek to maximize the potential of the Internet to inform our patients by advising them how and where to look for relevant information.