Minimal fresh gas flow sevoflurane anesthesia and postoperative acute kidney injury in on-pump cardiac surgery: a randomized comparative trial

BACKGROUND

Compound A is generated by sevoflurane when it reacts with carbon dioxide absorbers with strong bases at minimal fresh gas flow (FGF) and is nephrotoxic in animals. No conclusive data has shown increased risk in humans. The aim of this study was to investigate if minimal FGF promotes an increase in the incidence of acute kidney injury (AKI) when compared to high FGF in patients undergoing on-pump cardiac surgery under sevoflurane anesthesia.

METHODS

Two hundred and four adult patients scheduled for on-pump cardiac surgery under sevoflurane anesthesia were randomly allocated to two groups differentiated by FGF: minimal FGF (0.5 L.min^-1) or high FGF (2.0 L.min^-1). Baseline creatinine measured before surgery was compared daily to values assayed on the first five postoperative days, and 24-hour urinary output was monitored, according to the KDIGO (Kidney Disease Improving Global Outcomes) guideline to define postoperative cardiac surgery-associated acute kidney injury (CSA-AKI). Creatinine measurements were also obtained 20 and 120 days after hospital discharge.

RESULTS

Postoperative AKI occurred in 55 patients, 26 patients (29.5%) in the minimal FGF group and 29 patients (31.5%) in the high FGF group (p = 0.774). Twenty days after discharge, 11 patients (6.1%) still had CSA-AKI and 120 days after discharge only 2 patients (1.6%) still had CSA-AKI.

CONCLUSIONS

When compared to high FGF, minimal FGF sevoflurane anesthesia during on-pump cardiac surgery is not associated with increased risk of postoperative AKI in this population at high risk for renal injury.

Effects of Plasma-Lyte® and 0.9% saline in renal function after deceased-donor kidney transplant: a randomized controlled trial

BACKGROUND

The influence of different crystalloid solutions infused during deceased-donor kidney transplant on the incidence of delayed graft function remains unclear. We investigated the influence of Plasma-Lyte® vs. 0.9% saline on the incidence of delayed graft function in deceased-donor kidney transplant recipients.

METHODS

We conducted a single-blind randomized controlled trial of 104 patients aged 18 to 65 years who underwent deceased-donor kidney transplant under general anesthesia. Patients were randomly assigned to receive either Plasma-Lyte® (n = 52) or 0.9% saline (n = 52), at the same infusion volume, for intraoperative fluid replacement. The primary outcome was the occurrence of delayed graft function. Secondary outcomes included metabolic and electrolytic changes at the end of surgery.

RESULTS

Two patients in the Plasma-Lyte® group and one in the 0.9% saline group died postoperatively and were not included for analysis. The incidence of delayed graft function in Plasma-Lyte® and 0.9% saline groups were 60.0% (95% Confidence Interval [95% CI 46.2-72.4]) and 74.5% (95% CI 61.1-84.4), respectively (p = 0.140). Mean (standard deviation) values of immediate postoperative pH and serum chloride levels in Plasma-Lyte® and 0.9% saline groups were 7.306 (0.071) and 7.273 (0.061) (p = 0.013), and 99.6 (4.2) mEq.L^-1 and 103.3 (5.6) mEq.L^-1, respectively (p < 0.001). All other postoperative metabolic and electrolyte variables were not statistically different at the immediate postoperative period (p > 0.05).

CONCLUSION

In deceased-donor kidney transplant recipients, the incidence of delayed graft function is not influenced by Plasma-Lyte® or 0.9% saline used for intraoperative fluid replacement.

Oxidative stress, DNA damage, inflammation and gene expression in occupationally exposed university hospital anesthesia providers

Considering the importance and lack of data of toxicogenomic approaches on occupational exposure to anesthetics, we evaluated possible associations between waste anesthetic gases (WAGs) exposure and biological effects including oxidative stress, DNA damage, inflammation, and transcriptional modulation. The exposed group was constituted by anesthesia providers who were mainly exposed to the anesthetics sevoflurane and isoflurane (10 ppm) and to a lesser degree to nitrous oxide (150 ppm), and the control group was constituted by physicians who had no exposure to WAGs. The oxidative stress markers included oxidized DNA bases (comet assay), malondialdehyde (high-performance liquid chromatography [HPLC]), nitric oxide metabolites (ozone-chemiluminescence), and antioxidative markers, including individual antioxidants (HPLC) and antioxidant defense marker (ferric reducing antioxidant power by spectrophotometry). The inflammatory markers included high-sensitivity C-reactive protein (chemiluminescent immunoassay) and the proinflammatory interleukins IL-6, IL-8 and IL-17A (flow cytometry). Telomere length and gene expression related to DNA repair (hOGG1 and XRCC1), antioxidant defense (NRF2) and inflammation (IL6, IL8 and IL17A) were evaluated by real-time quantitative polymerase chain reaction. No significant differences (p > .0025) between the groups were observed for any parameter evaluated. Thus, under the conditions of the study, the findings suggest that occupational exposure to WAGs is not associated with oxidative stress or inflammation when evaluated in serum/plasma, with DNA damage evaluated in lymphocytes and leucocytes or with molecular modulation assessed in peripheral blood cells in university anesthesia providers. However, it is prudent to reduce WAGs exposure and to increase biomonitoring of all occupationally exposed professionals.

Association between intra-operative cardiac arrest and country Human Development Index status: a systematic review with meta-regression analysis and meta-analysis of observational studies. Anaesthesia 2021;76:1259-1273. [PMID: 33512708 DOI: 10.1111/anae.15374]

Intra-operative cardiac arrests differ from most in-hospital cardiac arrests because they reflect not only the patient's condition but also the quality of surgery and anaesthesia care provided. We assessed the relationship between intra-operative cardiac arrest rates and country Human Development Index (HDI), and the changes occurring in these rates over time. We searched PubMed, EMBASE, Scopus, LILACS, Web of Science, CINAHL and SciELO from inception to 29 January 2020. For the global population, rates of intra-operative cardiac arrest and baseline ASA physical status were extracted. Intra-operative cardiac arrest rates were analysed by time, country HDI status and ASA physical status using meta-regression analysis. Proportional meta-analysis was performed to compare intra-operative cardiac arrest rates and ASA physical status in low- vs. high-HDI countries and in two time periods. Eighty-two studies from 25 countries with more than 29 million anaesthetic procedures were included. Intra-operative cardiac arrest rates were inversely correlated with country HDI (p = 0.0001); they decreased over time only in high-HDI countries (p = 0.040) and increased with increasing ASA physical status (p < 0.0001). Baseline ASA physical status did not change in high-HDI countries (p = 0.106), while it decreased over time in low-HDI countries (p = 0.040). In high-HDI countries, intra-operative cardiac arrest rates (per 10,000 anaesthetic procedures) decreased from 9.59 (95%CI 6.59-13.16) pre-1990 to 5.17 (95%CI 4.42-5.97) in 1990-2020 (p = 0.013). During the same time periods, no improvement was observed in the intra-operative cardiac arrest rates in low-HDI countries (p = 0.498). Odds ratios of intra-operative cardiac arrest rates in ASA 3-5 patients were 8.48 (95%CI 1.67-42.99) times higher in low-HDI countries than in high-HDI countries (p = 0.0098). Intra-operative cardiac arrest rates are related to country-HDI and decreased over time only in high-HDI countries. The widening gap in these rates between low- and high-HDI countries needs to be addressed globally.

Strategies to optimize MEDLINE and EMBASE search strategies for anesthesiology systematic reviews. An experimental study

BACKGROUND

A high-quality electronic search is essential for ensuring accuracy and comprehensiveness among the records retrieved when conducting systematic reviews. Therefore, we aimed to identify the most efficient method for searching in both MEDLINE (through PubMed) and EMBASE, covering search terms with variant spellings, direct and indirect orders, and associations with MeSH and EMTREE terms (or lack thereof).

DESIGN AND SETTING

Experimental study. UNESP, Brazil.

METHODS

We selected and analyzed 37 search strategies that had specifically been developed for the field of anesthesiology. These search strategies were adapted in order to cover all potentially relevant search terms, with regard to variant spellings and direct and indirect orders, in the most efficient manner.

RESULTS

When the strategies included variant spellings and direct and indirect orders, these adapted versions of the search strategies selected retrieved the same number of search results in MEDLINE (mean of 61.3%) and a higher number in EMBASE (mean of 63.9%) in the sample analyzed. The numbers of results retrieved through the searches analyzed here were not identical with and without associated use of MeSH and EMTREE terms. However, association of these terms from both controlled vocabularies retrieved a larger number of records than did the use of either one of them.

CONCLUSIONS

In view of these results, we recommend that the search terms used should include both preferred and non-preferred terms (i.e. variant spellings and direct/indirect order of the same term) and associated MeSH and EMTREE terms, in order to develop highly-sensitive search strategies for systematic reviews.

Total Spinal Anesthesia Failure: Have You Assessed the Sensory Anesthesia in Sacral Dermatomes?

Intrathecal local anesthetic maldistribution is a well-known cause of spinal anesthesia failure (SAF). This could potentially result in sensory blockade restricted to the sacral dermatomes. We sought to determine the overall incidence of SAF and the role of sacral dermatomes in differentiating between total and partial failures. Of the 3111 spinals prospectively examined, 194 (6.2%) were classified as failures. Of the 72 presumed total failures based on the initial assessment, evaluation of the sacral dermatomes revealed sensory blockade in 32 (44%; 95% confidence interval, 32.7%-56.6%). Sacral dermatome assessment after SAF may be important in safely guiding subsequent anesthetic management.

[Comparison of waste anesthetic gases in operating rooms with or without an scavenging system in a Brazilian University Hospital]

BACKGROUND AND OBJECTIVES

Occupational exposure to waste anesthetic gases in operating room (OR) without active scavenging system has been associated with adverse health effects. Thus, this study aimed to compare the trace concentrations of the inhaled anesthetics isoflurane and sevoflurane in OR with and without central scavenging system.

METHOD

Waste concentrations of isoflurane and sevoflurane were measured by infrared analyzer at different locations (near the respiratory area of the assistant nurse and anesthesiologist and near the anesthesia station) and at two times (30 and 120minutes after the start of surgery) in both OR types.

RESULTS

All isoflurane and sevoflurane concentrations in unscavenged OR were higher than the US recommended limit (2 parts per million), regardless of the location and time evaluated. In scavenged OR, the average concentrations of isoflurane were within the limit of exposure, except for the measurements near the anesthesia station, regardless of the measurement times. For sevoflurane, concentrations exceeded the limit value at all measurement locations and at both times.

CONCLUSIONS

The exposure to both anesthetics exceeded the international limit in unscavenged OR. In scavenged OR, the concentrations of sevoflurane, and to a lesser extent those of isoflurane, exceeded the recommended limit value. Thus, the OR scavenging system analyzed in the present study decreased the anesthetic concentrations, although not to the internationally recommended values.

The effects of tracheal tube cuffs filled with air, saline or alkalinised lidocaine on haemodynamic changes and laryngotracheal morbidity in children: a randomised, controlled trial

We studied the effects of tracheal tube cuffs filled with air, saline or alkalinised lidocaine on haemodynamic changes during tracheal extubation and postoperative laryngotracheal morbidity in children. We randomly allocated 164 children aged 3-13 years undergoing general anaesthesia to one of four groups; tracheal tube cuffs filled with air (n = 41); saline (n = 41); alkalinised lidocaine 0.5% (n = 41); or alkalinised lidocaine 1% (n = 41). Intracuff pressure was monitored and maintained below 20 cmH₂ O. The mean (SD) increases in systolic blood pressure after tracheal extubation compared with before extubation were 10.9 (10.8) mmHg, 7.3 (17.7) mmHg, 4.1 (10.5) mmHg and 1.9 (9.5) mmHg in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p = 0.021). The mean (SD) increases in diastolic blood pressure after tracheal extubation compared with before extubation were 3.9 (9.7) mmHg, 7.9 (14.6) mmHg, 0.7 (10.4) mmHg and 3.6 (6.9) mmHg in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p = 0.019). The mean (SD) increases in heart rate after tracheal extubation compared with before extubation were 14.2 (7.6) beats.min^-1 , 15.5 (13.1) beats.min^-1 , 5.2 (9.6) beats.min^-1 and 4.1 (6.6) beats.min^-1 in the air, saline, 0.5% and 1% alkalinised lidocaine groups, respectively (p < 0.001). The incidence of sore throat 8 h after tracheal extubation was 22.0% in the air-filled group, 9.8% in the saline group, 4.9% in the 0.5% alkalinised lidocaine group and 2.4% in the 1% alkalinised lidocaine group, p = 0.015. We conclude that filling the tracheal tube cuff with alkalinised lidocaine-filled reduces the haemodynamic response to tracheal extubation and postoperative laryngotracheal morbidity in children.

Serum concentrations and renal expressions of IL-1 and TNF-a early after hemorrhage in rats under the effect of glibenclamide

PURPOSE

To investigate changes in the serum concentration and renal expression of IL-1 and TNF-α cytokines in rats that received sevoflurane and glibenclamide prior to hemorrhage.

METHODS

Two groups of sevoflurane-anesthetized Wistar rats (n=10): G1 (control) and G2 (glibenclamide, 1 µg/g i.v.); hemorrhage of 30% blood volume (10% every 10 min), with replacement using Ringer solution, 5 ml/kg/h. Serum concentrations of IL-1 and TNF-α were studied in the first hemorrhage (T1) and 50 min later (T2), renal expression, at T2.

RESULTS

In serum, G1 TNF-α (pg/mL) was T1=178.6±33.5, T2=509.2±118.8 (p<0.05); IL-1 (pg/mL) was T1=148.8±31.3, T2=322.6±115.4 (p<0.05); in G2, TNF-α was T1=486.2±83.6, T2=261.8±79.5 (p<0.05); IL-1 was T1=347.0±72.0, T2= 327.3±90.9 (p>0.05). The expression of TNF-α and IL-1 in the glomerular and tubular cells was significantly higher in the G2 group.

CONCLUSIONS

Hemorrhage and glibenclamide elevated TNF-α and IL-1 concentrations in serum and kidneys. High levels of TNF-α already present before the hemorrhage in the glibenclamide group may have attenuated the damages found in the kidneys after the ischemia event.

Bedside tests to predict laryngoscopic difficulty in pediatric patients

BACKGROUND AND OBJECTIVES

Pediatric airway management is a priority during anesthesia, critical care and emergency medicine. The purpose of this study is to validate bedside tests that predict airway management difficulty in anesthetized children.

METHODS

Children under 12 years of age were recruited in a cross-sectional study to assess the value of some anthropometric measures as predictors of laryngoscopic difficulty. The patients were divided into three groups by age. Weight, height, neck circumference, BMI (body mass index), inter incisors distance thyromental distance, sternomental distance, frontal plane to chin distance (FPCD) and the Mallampati index were determined and were correlated with the CML (Cormack & Lehane classification).

RESULTS

The incidence of difficult laryngoscopy (CML 3 or 4) was 3.58%. Factors that were significantly associated with laryngoscopic difficulty included short inter incisors distance, high FPCD, thyromental distance, sternomental distance and the Mallampati index. The FPCD/weight index exhibited a higher area under the ROC curve than any other variable considered.

CONCLUSIONS

This study confirms that the FPCD and the FPCD/weight ratio are the most consistent predictors of laryngoscopic difficulty in pediatric patients. For patients over 6 months of age, the IID also correlated with laryngoscopic difficulty. For children who were capable of obeying simple orders, the Mallampati test correlated better with laryngoscopic difficulty than did the Mallampati test with phonation. Our results strongly suggest that skilled professionals should perform airway management in children, especially in patients with a high FPCD or a high FPCD/weight ratio.

Differences between the real and the desired worlds in the results of clinical trials

OBJECTIVE

We refer to the effectiveness (known as pragmatic or real world) and efficacy (known as explanatory or desired or ideal world) of interventions. However, these terms seem to be randomly chosen by investigators who design clinical trials and do not always reflect the true purpose of the study. A pragmatic-explanatory continuum indicator summary tool was thus developed with the aim of identifying the characteristics of clinical trials that distinguish between effectiveness and efficacy issues. We verified whether clinical trials used the criteria proposed by the indicator summary tool, and we categorized these clinical trials according to a new classification.

METHOD

A systematic survey of randomized clinical trials was performed. We added a score ranging from 0 (more efficacious) to 10 (more effective) to each domain of the indicator summary tool and proposed the following classifications: high efficacy (<25), moderate efficacy (25-50), moderate effectiveness (51-75), and high effectiveness (<75).

RESULTS

A total of 844 randomized trials were analyzed. No analyzed trials used the criteria proposed by the indicator summary tool. Approximately 44% of the trials were classified as having moderate effectiveness, and 43.82% were classified as having moderate efficacy.

CONCLUSIONS

Most clinical trials used the term "efficacy" to illustrate the application of results in clinical practice, but the majority of those were classified as having moderate effectiveness according to our proposed score. The classification based on the 0-100 score is still highly subjective and can be easily misunderstood in all domains based on each investigator's own experiences and knowledge.

Comparison of oxidative stress in ASA physical status I patients scheduled for minimally invasive surgery under balanced or intravenous anesthesia

BACKGROUND

The effects of anesthetics on inflammation and oxidative parameters, evaluated in patients without comorbidities undergoing minor surgery, remain unknown. The present study aimed to investigate the inflammatory and oxidative stress status in adult patients undergoing elective minimally invasive surgery, using different anesthetic techniques.

METHODS

Thirty patients classified as ASA physical status I, who were scheduled for minor surgeries (tympanoplasty or septoplasty), were randomly allocated into two groups: balanced (BAL) anesthesia maintained with isoflurane or total intravenous anesthesia (TIVA) with propofol. Blood samples were drawn prior to the induction of anesthesia (baseline), 120 min after the beginning of anesthesia and one day after surgery. The proinflammatory cytokine IL-6 was determined by flow cytometry; DNA oxidation was evaluated by the single cell gel electrophoresis assay, and plasma malondialdehyde (lipid peroxidation biomarker) and antioxidant status were determined through fluorometry.

RESULTS

Increased IL-6 was observed one day after surgery in both groups (P=0.0001). Malondialdehyde levels did not change among the time points assessed or between the groups (P>0.05). Whereas BAL anesthesia had no effect on acid nucleic and antioxidant status, TIVA decreased oxidized/alkylated purines (P=0.03) and increased antioxidant status (P=0.002) during anesthesia. The two groups did not differ significantly in DNA oxidation or antioxidant status (P>0.05).

CONCLUSION

BAL anesthesia maintained with isoflurane and TIVA maintained with propofol are safe by virtue of not causing oxidative stress status in ASA physical status I patients undergoing minimally invasive surgeries. Moreover, even in minor surgeries, TIVA with propofol produces an antioxidant effect in patients.

Systematic reviews showed insufficient evidence for clinical practice in 2004: what about in 2011? The next appeal for the evidence-based medicine age

RATIONALE AND AIM

The aims of the Cochrane systematic reviews are to make readily available and up-to-date information for clinical practice, offering consistent evidence and straightforward recommendations. In 2004, we evaluated the conclusions from Cochrane systematic reviews of randomized controlled trials in terms of their recommendations for clinical practice and found that 47.83% of them had insufficient evidence for use in clinical practice. We proposed to reanalyze the reviews to evaluate whether this percentage had significantly decreased.

METHODS

A cross-sectional study of systematic reviews published in the Cochrane Library (Issue 7, 2011) was conducted. We randomly selected reviews across all 52 Cochrane Collaborative Review Groups.

RESULTS

We analyzed 1128 completed systematic reviews. Of these, 45.30% concluded that the interventions studied were likely to be beneficial, of which only 2.04% recommended no further research. In total, 45.04% of the reviews reported that the evidence did not support either benefit or harm, of which 0.8% did not recommend further studies and 44.24% recommended additional studies; the latter has decreased from our previous study with a difference of 3.59%.

CONCLUSION

Only a small number of the Cochrane collaboration's systematic reviews support clinical interventions with no need for additional research. A larger number of high-quality randomized clinical trials are necessary to change the 'insufficient evidence' scenario for clinical practice illustrated by the Cochrane database. It is recommended that we should produce higher-quality primary studies in active collaboration and consultation with global scholars and societies so that this can represent a major component of methodological advance in this context.

[Hoarseness after tracheal intubation.]

BACKGROUND AND OBJECTIVES

To describe the main causes of hoarseness after undergoing tracheal intubation.

CONTENTS

Hoarseness is one of the most common postoperatory symptoms after tracheal intubation and the effects vary in terms of duration, depending on the factors that caused it and on how severe the damage to the laryngeal structures. This study performed a brief check-up of the anatomical structures of the larynx, describing the main traumatic lesions in the region following tracheal intubation. It also emphasized the importance of caring for the larynx, as well as undergoing early diagnosis and treatment.

CONCLUSIONS

Traumatic lesions of the laryngeal structures that occur during intubation are the most common causes of hoarseness. As such, it is important to perform an early diagnosis and adopt preventive measures.

Prevention of renal ischemia/reperfusion injury in rats using acetylcysteine after anesthesia with isoflurane

PURPOSE: To evaluate the effect of N-acetylcysteine, as a renoprotective agent, when administered early after anesthesia induction, against ischemia/reperfusion injury in rats anesthetized with isoflurane. METHODS: Eighteen male Wistar rats weighing > 300g were anesthetized with isoflurane. The internal jugular vein and the left carotid artery were dissected and cannulated. The animals were randomly divided into GAcetyl, receiving intravenous N-acetylcysteine, 300mg/kg, and GIsot, isotonic saline. After 30 minutes, right nephrectomy was performed and the left renal artery was clamped during 45 minutes. The animals were sacrificed after 48 hours and blood samples were taken after anesthetic induction and upon sacrificing of the animals to evaluate blood creatinine. The kidneys were sent for histological analysis. RESULTS: The variation in serum creatinine was 2.33mg/dL ± 2.21 in GAcetyl and 4.38mg/dL ± 2.13 in GIsot (p=0.074). Two animals presented intense tubular necrosis in GAcetyl, compared to 5 in GIsot. Only GAcetyl presented animals free of tubular necrosis (two) and tubular degeneration (one). CONCLUSION: After renal ischemia/reperfusion, the rats which were given N-acetylcysteine presented less variation in serum creatinine and milder kidney injuries than the control group.

Anesthesia-related mortality in pediatric patients: a systematic review

This systematic review of the Brazilian and worldwide literature aimed to evaluate the incidence and causes of perioperative and anesthesia-related mortality in pediatric patients. Studies were identified by searching EMBASE (1951-2011), PubMed (1966-2011), LILACS (1986-2011), and SciElo (1995-2011). Each paper was revised to identify the author(s), the data source, the time period, the number of patients, the time of death, and the perioperative and anesthesia-related mortality rates. Twenty trials were assessed. Studies from Brazil and developed countries worldwide documented similar total anesthesia-related mortality rates (<1 death per 10,000 anesthetics) and declines in anesthesia-related mortality rates in the past decade. Higher anesthesia-related mortality rates (2.4-3.3 per 10,000 anesthetics) were found in studies from developing countries over the same time period. Interestingly, pediatric perioperative mortality rates have increased over the past decade, and the rates are higher in Brazil (9.8 per 10,000 anesthetics) and other developing countries (10.7-15.9 per 10,000 anesthetics) compared with developed countries (0.41-6.8 per 10,000 anesthetics), with the exception of Australia (13.4 per 10,000 anesthetics). The major risk factors are being newborn or less than 1 year old, ASA III or worse physical status, and undergoing emergency surgery, general anesthesia, or cardiac surgery. The main causes of mortality were problems with airway management and cardiocirculatory events. Our systematic review of the literature shows that the pediatric anesthesia-related mortality rates in Brazil and in developed countries are similar, whereas the pediatric perioperative mortality rates are higher in Brazil compared with developed countries. Most cases of anesthesia-related mortality are associated with airway and cardiocirculatory events. The data regarding anesthesia-related and perioperative mortality rates may be useful in developing prevention strategies.

Genotoxicity, cytotoxicity and gene expression in patients undergoing elective surgery under isoflurane anaesthesia

There are numerous studies reporting on the effects of inhalation anaesthesia in cells of exposed individuals but not much is known about the ability of isoflurane (ISF) to induce oxidative DNA damage. However, surgery is often associated with a temporary perioperative immunological alteration, and some volatile anaesthetics seem to contribute to a transient lymphocytopenia after surgery. We conducted a study to evaluate a possible genotoxic effect, including oxidative DNA damage, and apoptosis in peripheral lymphocytes of 20 patients American Society of Anaesthesiologists physical status I undergoing minor elective surgery lasting at least 120 min, under anaesthesia with ISF. We also investigated the expression of several genes in blood cells. Blood samples were collected at three time points: before anaesthesia (T(1)), 2 h after the beginning of anaesthesia (T(2)) and on the first post-operative day (T(3)). General DNA damage and oxidised bases (Fpg and endo III-sites) in blood lymphocytes were evaluated using the comet assay. Lymphocytes were phenotyped and apoptosis was evaluated by flow cytometry. In addition, expressions of hOGG1 and XRCC1, genes involved in DNA repair, and BCL2, a gene related to apoptosis, were assessed by quantitative real-time polymerase chain reaction. Results showed no statistically significant difference in the level of DNA damage and oxidised bases among the three sampling times. Anaesthesia with ISF did not increase the percentage of cells in early or late apoptosis in cytotoxic or helper T lymphocytes. Lower hOGG1 and BCL2 expressions were detected at T(3) in comparison to the other two previous time points, and there was significantly lower expression of XRCC1 at T(3) in relation to T(2). In conclusion, the exposure to ISF did not result in genotoxicity and cytotoxicity in lymphocytes and in toxicogenomic effect in leukocytes, although DNA repair and apoptosis-related genes were down-regulated on the first post-operative day.

Enzyme biomarkers of renal tubular injury in arterial surgery patients

OBJECTIVE

The aim of this study was to verify whether preoperative diabetes, hypertension, and renal function had any relationship with postoperative tubule function in patients submitted to anesthesia for arterial surgery.

METHODS

Prospective observational study. One hundred and forty-four patients submitted to anesthesia for arterial surgery enrolled consecutively and divided into four groups: G1--diabetes and hypertension; G2--diabetes; G3--hypertension; and G4--without hypertension or diabetes. Urine was obtained for laboratory analysis of urinary creatinine (Ucr), alkaline phosphatase (AP), γ-glutamyltransferase (γGT), and blood for cystatin C and creatinine before the surgery (M1) and 24 h after the surgery (M2).

RESULTS

Values of γGT, γGT/Ucr, and AP × γGT/Ucr increased at M2 in G4. Patients without renal function compromise (GFR ≥90 mL/min/1.73 m(2)) presented increased γGT/Ucr and AP × γGT/Ucr values at M2 and those with slightly compromised renal function (60-89 mL/min/1.73 m(2)) presented increased γGT values at M2. There was no correlation between deltaCystatin C and deltaAP, deltaγGT, deltaγGT/Ucr, deltaAP/Ucr, and deltaAP × γGT/Ucr.

CONCLUSIONS

Diabetes, hypertension, and preoperative renal function seem to interfere in tubular enzymuria immediately after surgery in arteriopathic patients. However, when these markers do not increase in postoperative period, renal dysfunction cannot be discarded.

Mortality in anesthesia: a systematic review

This systematic review of the Brazilian and worldwide literature aims to evaluate the incidence and causes of perioperative and anesthesia-related mortality. Studies were identified by searching the Medline and Scielo databases, followed by a manual search for relevant articles. Our review includes studies published between 1954 and 2007. Each publication was reviewed to identify author(s), study period, data source, perioperative mortality rates, and anesthesia-related mortality rates. Thirty-three trials were assessed. Brazilian and worldwide studies demonstrated a similar decline in anesthesia-related mortality rates, which amounted to fewer than 1 death per 10,000 anesthetics in the past two decades. Perioperative mortality rates also decreased during this period, with fewer than 20 deaths per 10,000 anesthetics in developed countries. Brazilian studies showed higher perioperative mortality rates, from 19 to 51 deaths per 10,000 anesthetics. The majority of perioperative deaths occurred in neonates, children under one year, elderly patients, males, patients of ASA III physical status or poorer, emergency surgeries, during general anesthesia, and cardiac surgery followed by thoracic, vascular, gastroenterologic, pediatric and orthopedic surgeries. The main causes of anesthesia-related mortality were problems with airway management and cardiocirculatory events related to anesthesia and drug administration. Our systematic review of the literature shows that perioperative mortality rates are higher in Brazil than in developed countries, while anesthesia-related mortality rates are similar in Brazil and in developed countries. Most cases of anesthesia-related mortality are associated with cardiocirculatory and airway events. These data may be useful in developing strategies to prevent anesthesia-related deaths.

Postoperative renal function evaluation, through RIFLE criteria, of elderly patients who underwent femur fracture surgery under spinal anesthesia

INTRODUCTION

The postoperative acute renal failure (ARF) incidence in different kinds of surgery has rarely been studied. Age, cardiac dysfunction, previous renal dysfunction, intraoperative hypoperfusion, and use of nephrotoxic medications are mentioned as risk factors for ARF at the postoperative period. The postoperative ARF definition was based on the creatinine increase by the RIFLE classification (R = risk, I = injury, F = failure, L = loss, E = end stage), which corresponds to a 1.5 creatinine increase, two to three times, respectively, above the basal value. This study aimed to evaluate the postoperative ARF incidence in elderly patients who underwent femur fracture surgery under subarachnoid anesthesia and stratify it by the RIFLE criteria.

METHODS

Ninety patients older than 65 years under spinal anesthesia with fixed dosage of 15 mg of 0.5% isobaric bupivacaine associated with morphine 50 mug were studied. Immediate postoperative creatinine was considered basal and compared with maximal creatinine evaluated at 24, 48, and 72 postoperative hours.

RESULTS

The mean age of the patients was 80.27 years. ARF incidence was 24.44% and stratified this way: R = 21.11% and I = 3.33%.

CONCLUSIONS

In conclusion, the postoperative ARF incidence after femur fracture surgery in patients over 65 years was 24.44%. By analyzing the stratification based on the RIFLE classification, the incidence was categorized as Risk (R) = 21.11% and Injury (I) = 3.33%.

Emergence agitation in pediatric anesthesia: current features

OBJECTIVE

Postoperative agitation in children is a well-documented clinical phenomenon with incidence ranging from 10% to 67%. There is no definitive explanation for this agitation. Possible causes include rapid awakening in unfamiliar settings, pain (wounds, sore throat, bladder distension, etc.), stress during induction, hypoxemia, airway obstruction, noisy environment, anesthesia duration, child's personality, premedication and type of anesthesia. The purpose of this paper is to discuss the possible causes of postoperative agitation in children, providing a foundation for better methods of identifying and preventing this problem.

SOURCES

MEDLINE and PubMed were searched using the following words: emergence, agitation, incidence, etiology, diagnosis, treatment, children, pediatric, anesthesia.

SUMMARY OF THE FINDINGS

This study includes a review of potential agitation trigger factors and a proposal for a standardized diagnostic score system, in addition to measures to improve prevention and treatment.

CONCLUSION

No single factor can identified as the cause of postoperative agitation, which should therefore be considered a syndrome made up of biological, pharmacological, psychological and social components, and which anesthesiologists and pediatric intensive care specialists should be prepared to identify, prevent and intervene appropriately as necessary.

Preoperative warming combined with intraoperative skin-surface warming does not avoid hypothermia caused by spinal anesthesia in patients with midazolam premedication

CONTEXT AND OBJECTIVE

Inadvertent perioperative hypothermia is common during spinal anesthesia and after midazolam administration. The aim of this study was to evaluate the effects of intraoperative skin-surface warming with and without 45 minutes of preoperative warming in preventing intraoperative and postoperative hypothermia caused by spinal anesthesia in patients with midazolam premedication.

DESIGN AND SETTING

Prospective and randomized study at Hospital das Clínicas, Universidade Estadual Paulista, Botucatu.

METHODS

Thirty patients presenting American Society of Anesthesiologists (ASA) physical status I and II who were scheduled for elective lower abdominal surgery were utilized. The patients received midazolam premedication (7.5 mg by intramuscular injection) and standard spinal anesthesia. Ten patients (Gcontrol) received preoperative and intraoperative passive thermal insulation. Ten patients (Gpre+intra) underwent preoperative and intraoperative active warming. Ten patients (Gintra) were only warmed intraoperatively.

RESULTS

After 45 min of preoperative warming, the patients in Gpre+intra had significantly higher core temperatures than did the patients in the unwarmed groups (Gcontrol and Gintra) before the anesthesia (p < 0.05) but not at the beginning of surgery (p > 0.05). The patients who were warmed intraoperatively had significantly higher core temperatures than did the patients in Gcontrol at the end of surgery (p < 0.05). All the patients were hypothermic at admission to the recovery room (T CORE < 36 degrees C).

CONCLUSIONS

Forty-five minutes of preoperative warming combined with intraoperative skin-surface warming does not avoid but minimizes hypothermia caused by spinal anesthesia in patients with midazolam premedication.

Perioperative cardiac arrest and its mortality in children. A 9-year survey in a Brazilian tertiary teaching hospital

BACKGROUND

The incidence of perioperative cardiac arrest and mortality in children is higher than in adults. This survey evaluated the incidence, causes, and outcome of perioperative cardiac arrests in a pediatric surgical population in a tertiary teaching hospital between 1996 and 2004.

METHODS

The incidence of cardiac arrest during anesthesia was identified from an anesthesia database. During the study period, 15,253 anesthetics were performed in children. Data collected included patient demographics, surgical procedures (elective, urgent, or emergency), ASA physical status classification, anesthesia provider information, type of surgery, surgical areas, and outcome. All cardiac arrests were reviewed and grouped by the cause of arrest and death into one of four groups: totally anesthesia-related, partially anesthesia-related, totally surgery-related, or totally child disease or condition-related.

RESULTS

There were 35 cardiac arrests (22.9 : 10,000) and 15 deaths (9.8 : 10,000). Major risk factors for cardiac arrest were neonates and children under 1 year of age (P < 0.05) with ASA III or poorer physical status (P < 0.05), in emergency surgery (P < 0.05), and general anesthesia (P < 0.05). Child disease/condition was the major cause of cardiac arrest or death (P < 0.05). There were seven cardiac arrests because of anesthesia (4.58 : 10,000)--four totally (2.62 : 10,000) and three partially related to anesthesia (1.96 : 10,000). There were no anesthesia attributable deaths reported. The main causes of anesthesia attributable cardiac arrest were respiratory events (71.5%) and medication-related events (28.5%).

CONCLUSIONS

Perioperative cardiac arrests were relatively higher in neonates and infants than in older children with severe underlying disease and during emergency surgery. The fact that all anesthesia attributable cardiac arrests were related to airway management and medication administration is important in prevention strategies.

Perioperative cardiac arrest: a study of 53 718 anaesthetics over 9 yr from a Brazilian teaching hospital

BACKGROUND

Little information exists regarding factors influencing perioperative cardiac arrests and their outcome. This survey evaluated the incidence, causes and outcome of perioperative cardiac arrests in a Brazilian tertiary general teaching hospital between April 1996 and March 2005.

METHODS

The incidence of cardiac arrest during anaesthesia was prospectively identified from an anaesthesia database. There were 53,718 anaesthetics during the study period. Data collected included patient characteristics, surgical procedures (elective, urgent or emergency), ASA physical status classification, anaesthesia provider information, type of surgery, surgical areas and outcome. All cardiac arrests were retrospectively reviewed and grouped by cause of arrest and death into one of four groups: totally anaesthesia related, partially anaesthesia related, totally surgery related or totally patient disease or condition related.

RESULTS

One hundred and eighty-six cardiac arrests (34.6:10,000) and 118 deaths (21.97:10,000) were found. Major risk factors for cardiac arrest were neonates, children under 1 yr and the elderly (P<0.05), male patients with ASA III or poorer physical status (P<0.05), in emergency surgery (P<0.05) and under general anaesthesia (P<0.05). Patient disease/condition was the major cause of cardiac arrest or death (P<0.05). There were 18 anaesthesia-related cardiac arrests (3.35:10,000) -- 10 totally attributed (1.86:10,000) and 8 partially related to anaesthesia (1.49:10,000). There were 6 anaesthesia-related deaths (1.12:10,000) -- 3 totally attributable and 3 partially related to anaesthesia (0.56:10,000 in both cases). The main causes of anaesthesia-related cardiac arrest were respiratory events (55.5%) and medication-related events (44.5%).

CONCLUSIONS

Perioperative cardiac arrests were relatively higher in neonates, infants, the elderly and in males with severe underlying disease and under emergency surgery. All anaesthesia-related cardiac arrests were related to airway management and medication administration which is important for prevention strategies.

The Early Systemic and Gastrointestinal Oxygenation Effects of Hemorrhagic Shock Resuscitation with Hypertonic Saline and Hypertonic Saline 6% Dextran-70: A Comparative Study in Dogs

The smaller volemic state from hypertonic (7.5%) saline (HS) solution administration in hemorrhagic shock can determine lesser systemic oxygen delivery and tissue oxygenation than conventional plasma expanders. In a model of hemorrhagic shock in dogs, we studied the systemic and gastrointestinal oxygenation effects of HS and hyperoncotic (6%) dextran-70 in combination with HS (HSD) solutions in comparison with lactated Ringer's (LR) and (6%) hydroxyethyl starch (HES) solutions. Forty-eight mongrel dogs were anesthetized, mechanically ventilated, and subjected to splenectomy. A gastric air tonometer was placed in the stomach for intramucosal gastric CO(2) (Pgco(2)) determination and for the calculation of intramucosal pH (pHi): The dogs were hemorrhaged (42% of blood volume) to hold mean arterial blood pressure at 40-50 mm Hg over 30 min and were then resuscitated with LR (n = 12) in a 3:1 relation to removed blood volume; HS (n = 12), 6 mL/kg; HSD (n = 12), 6 mL/kg; and HES (mean molecular weight, 200 kDa; degree of substitution, 0.5) (n = 12) in a 1:1 relation to the removed blood volume. Hemodynamic, systemic, and gastric oxygenation variables were measured at baseline, after 30 min of hemorrhage, and 5, 60, and 120 min after intravascular fluid resuscitation. After fluid resuscitation, HS showed significantly lower arterial pH and mixed venous Po(2) and higher systemic oxygen uptake index and systemic oxygenation extraction than LR and HES (P < 0.05), whereas HSD showed significantly lower arterial pH than LR and HES (P < 0.05). Only HS and HSD did not return arterial pH and pHi to control levels (P < 0.05). In conclusion, all solutions improved systemic and gastrointestinal oxygenation after hemorrhagic shock in dogs. However, the HS solution showed the worst response in comparison to LR and HES solutions in relation to systemic oxygenation, whereas HSD showed intermediate values. HS and HSD solutions did not return regional oxygenation to control values.

Does sealing endotracheal tube cuff pressure diminish the frequency of postoperative laryngotracheal complaints after nitrous oxide anesthesia?

STUDY OBJECTIVES

To study endotracheal tube (ETT) cuff pressures during nitrous oxide (N2O) anesthesia when the cuffs are inflated with air to achieve sealing pressure, and to evaluate the frequency of postoperative laryngotracheal complaints.

DESIGN

Prospective, randomized, blind study.

SETTING

Metropolitan teaching hospital.

PATIENTS

50 ASA physical status I and II patients scheduled for elective abdominal surgery.

INTERVENTIONS

Patients received standard general anesthesia with 66% N2O in oxygen. In 25 patients, the ETT cuff was inflated with air to achieve a sealing pressure (Pseal group). In 25 patients, the ETT cuff was inflated with air to achieve a pressure of 25 cm H2O (P25 group).

MEASUREMENTS AND MAIN RESULTS

ETT intracuff pressures were recorded before (control) and at 30, 60, 90, 120, and 150 minutes during N2O administration. We investigated the frequency and intensity of sore throat, hoarseness, and dysphagia in patients in the Post-Anesthesia Care Unit (PACU) and 24 hours following tracheal extubation. The cuff pressures in the Pseal group were significantly lower than in the P25 group at all time points studied (p < 0.001), with a significant increase with time in both groups (p < 0.001). The cuff pressures exceeded the critical pressure of 30 cm H2O only after 90 minutes in the Pseal group and already by 30 minutes in the P25 group. The frequency and intensity of sore throat, hoarseness, and dysphagia were similar in both groups in the PACU and 24 hours after tracheal extubation (p > 0.05).

CONCLUSIONS

Minimum ETT sealing cuff pressure during N2O anesthesia did not prevent, but instead attenuated, the increase in cuff pressure and did not decrease postoperative laryngotracheal complaints.

Effects of clonidine associated to hyperbaric bupivacaine during high-level spinal anesthesia

BACKGROUND AND OBJECTIVES

Published data suggest that clonidine, an alpha2-adrenergic agonist, in association with bupivacaine, may increase the incidence of intraoperative hypotension and bradycardia during high-level spinal anesthesia. This study aimed at determining the synergistic potential of two clonidine doses (45 and 75 microg) and hyperbaric bupivacaine on characteristics and hemodynamic effects of high-level (T4) spinal anesthesia.

METHODS

Participated in this randomized double-blind study, 60 ASA I patients scheduled for lower abdominal and limb surgery. Spinal anesthesia was induced with 17.5 mg (3.5 ml) of 0.5% hyperbaric bupivacaine plus the association of the following drugs: Control group (n = 20) - 0.5 ml isotonic saline solution; Clon 45 group (n = 20) - 45 microg (0.3 ml) clonidine + 0.2 ml isotonic saline solution; and Clon 75 (n = 20) - 75 microg (0.5 ml) clonidine. Surgery was only started when high-level (T4) analgesia was consistently obtained.

RESULTS

Sensory and motor block onset did not significantly differ among groups (p > 0.05). Both clonidine doses significantly prolonged analgesic block at T8 and motor block level 3 duration (determined by modified Bromage scale) (p < 0.05). Intraoperative arterial hypotension was observed only in Clon 75 group as compared to Control group (p < 0.05), while Clon 45 group had intermediate incidence between both groups. There was no significant difference among groups in bradycardia (p > 0.05). Both clonidine doses prolonged postoperative analgesia (time from spinal block to first postoperative analgesic request) (p < 0.05).

CONCLUSIONS

High clonidine dose (75 microg) associated to hyperbaric bupivacaine during high-level spinal anesthesia (T4) induces a higher incidence of arterial hypotension but prolongs sensory block and postoperative analgesia similar to lower clonidine dose (45 microg) during upper spinal anesthesia.