Global anaesthesia-related cardiac arrest rates in children: a systematic review and meta-analysis.

BACKGROUND: Neonates and infants have a higher perioperative risk of cardiac arrest and mortality than adults. The Human Development Index (HDI) ranges from 0 to 1, representing the lowest and highest levels of development, respectively. The relation between anaesthesia safety and country HDI has been described previously. We examined the relationship among the anaesthesia-related cardiac arrest rate (ARCAR), country HDI, and time in a mixed paediatric patient population. METHODS: Electronic databases were searched up to July 2022 for studies reporting 24-h postoperative ARCARs in children. ARCARs (per 10,000 anaesthetic procedures) were analysed in low-HDI (HDI<0.8) vs high-HDI countries (HDI≥0.8) and over time (pre-2001 vs 2001-22). The magnitude of these associations was studied using systematic review methods with meta-regression analysis and meta-analysis. RESULTS: We included 38 studies with 5,493,489 anaesthetic procedures and 1001 anaesthesia-related cardiac arrests. ARCARs were inversely correlated with country HDI (P<0.0001) but were not correlated with time (P=0.82). ARCARs did not change between the periods in either high-HDI or low-HDI countries (P=0.71 and P=0.62, respectively), but were higher in low-HDI countries than in high-HDI countries (9.6 vs 2.0; P<0.0001) in 2001-22. ARCARs were higher in children aged <1 yr than in those ≥1 yr in high-HDI (10.69 vs 1.48; odds ratio [OR] 8.03, 95% confidence interval [CI] 5.96-10.81; P<0.0001) and low-HDI countries (36.02 vs 2.86; OR 7.32, 95% CI 3.48-15.39; P<0.0001) in 2001-22. CONCLUSIONS: The high and alarming anaesthesia-related cardiac arrest rates among children younger than 1 yr of age in high-HDI and low-HDI countries, respectively, reflect an ongoing challenge for anaesthesiologists. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42021229919.

Perioperative mortality in older patients: a systematic review with a meta-regression analysis and meta-analysis of observational studies.

STUDY OBJECTIVE: Older patients have a higher probability of developing major complications during the perioperative period than other adult patients. Perioperative mortality depends on not only on a patient condition but also on the quality of perioperative care provided. We tested the hypothesis that the perioperative mortality rate among older patients has decreased over time and is related to a country's Human Development Index (HDI) status. DESIGN: A systematic review with a meta-regression and meta-analysis of observational studies that reported perioperative mortality rates in patients aged ≥60 years was performed. We searched the PubMed, EMBASE, LILACS and SciELO databases from inception to December 30, 2019. SETTING: Mortality rates up to the seventh postoperative day were evaluated. MEASUREMENTS: We evaluated the quality of the included studies. Perioperative mortality rates were analysed by time, country HDI status and baseline American Society of Anesthesiologists (ASA) physical status using meta-regression. Perioperative mortality and ASA status were analysed in low- and high-HDI countries during two time periods using proportion meta-analysis. MAIN RESULTS: We included 25 studies, which reported 4,412,100 anaesthesia procedures and 3568 perioperative deaths from 12 countries. Perioperative mortality rates in high-HDI countries decreased over time (P = 0.042). When comparing pre-1990 to 1990-2019, in high-HDI countries, the perioperative mortality rates per 10,000 anaesthesia procedures decreased 7.8-fold from 100.85 (95% CI 43.36 to 181.72) in pre-1990 to 12.98 (95% CI 6.47 to 21.70) in 1990-2019 (P < 0.0001). There were no studies from low-HDI countries pre-1990. In the period from 1990 to 2019, perioperative mortality rates did not differ between low- and high-HDI countries (P = 0.395) but the limited number of patients in low-HDI countries impaired the result. Perioperative mortality rates increased with increasing ASA status (P < 0.0001). There were more ASA III-V patients in high-HDI countries than in low-HDI countries (P < 0.0001), and the perioperative mortality rate increased 24-fold in ASA III-V patients compared with ASA I-II patients (P < 0.0001). CONCLUSION: The perioperative mortality rates in older patients have declined over the past 60 years in high-DHI countries, highlighting that perioperative safety in this population is increasing in these countries. Since data prior to 1990 were lacking in low-HDI countries, the evolution of their mortality rates could not be analysed. The perioperative mortality rate was similar in low- and high-HDI countries in the post-1990 period, but the low number of patients in the low-HDI countries does not allow a definitive conclusion.

Perioperative and anesthesia-related cardiac arrest and mortality rates in Brazil: A systematic review and proportion meta-analysis.

INTRODUCTION: Studies have shown that both perioperative and anesthesia-related cardiac arrest (CA) and mortality rates are much higher in developing countries than in developed countries. This review aimed to compare the rates of perioperative and anesthesia-related CA and mortality during 2 time periods in Brazil. METHODS: A systematic review with meta-analysis of full-text Brazilian observational studies was conducted by searching the Medline, EMBASE, LILACS and SciELO databases up to January 29, 2020. The primary outcomes were perioperative CA and mortality rates and the secondary outcomes included anesthesia-related CA and mortality events rates up to 48 postoperative hours. RESULTS: Eleven studies including 719,273 anesthetic procedures, 962 perioperative CAs, 134 anesthesia-related CAs, 1,239 perioperative deaths and 29 anesthesia-related deaths were included. The event rates were evaluated in 2 time periods: pre-1990 and 1990-2020. Perioperative CA rates (per 10,000 anesthetics) decreased from 39.87 (95% confidence interval [CI]: 34.60-45.50) before 1990 to 17.61 (95% CI: 9.21-28.68) in 1990-2020 (P < 0.0001), while the perioperative mortality rate did not alter (from 19.25 [95% CI: 15.64-23.24] pre-1990 to 25.40 [95% CI: 13.01-41.86] in 1990-2020; P = 0.1984). Simultaneously, the anesthesia-related CA rate decreased from 14.39 (95% CI: 11.29-17.86) to 3.90 (95% CI: 2.93-5.01; P < 0.0001), while there was no significant difference in the anesthesia-related mortality rate (from 1.75 [95% CI: 0.76-3.11] to 0.67 [95% CI: 0.09-1.66; P = 0.5404). CONCLUSIONS: This review demonstrates an important reduction in the perioperative CA rate over time in Brazil, with a large and consistent decrease in the anesthesia-related CA rate; however, there were no significant differences in perioperative and anesthesia-related mortality rates between the assessed time periods.

Perioperative and anesthesia-related cardiac arrests in geriatric patients: a systematic review using meta-regression analysis.

The worldwide population is aging, and the number of surgeries performed in geriatric patients is increasing. This systematic review evaluated anesthetic procedures to assess global data on perioperative and anesthesia-related cardiac arrest (CA) rates in geriatric surgical patients. Available data on perioperative and anesthesia-related CA rates over time and by the country's Human Development Index (HDI) were evaluated by meta-regression, and a pooled analysis of proportions was used to compare perioperative and anesthesia-related CA rates by HDI and time period. The meta-regression showed that perioperative CA rates did not change significantly over time or by HDI, whereas anesthesia-related CA rates decreased over time (P = 0.04) and in high-HDI (P = 0.015). Perioperative and anesthesia-related CA rates per 10,000 anesthetic procedures declined in high-HDI, from 38.6 before the 1990s to 7.7 from 1990-2017 (P < 0.001) and from 9.2 before the 1990s to 1.3 from 1990-2017 (P < 0.001), respectively. The perioperative CA rate from 1990-2017 was higher in low-HDI than in high-HDI countries (P < 0.001). Hence, a reduction in anesthesia-related CA rates over time was observed. Both perioperative and anesthesia-related CA rates only decreased with a high-HDI between time periods, and perioperative CA rates during 1990-2017 were 4-fold higher with low- compared to high-HDI in geriatric patients.

Effects of different fresh gas flows with or without a heat and moisture exchanger on inhaled gas humidity in adults undergoing general anaesthesia: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: The minimum inhaled gas absolute humidity level is 20 mgH2O l for short-duration use in general anaesthesia and 30 mgH2O l for long-duration use in intensive care to avoid respiratory tract dehydration. OBJECTIVE: The aim is to compare the effects of different fresh gas flows (FGFs) through a circle rebreathing system with or without a heat and moisture exchanger (HME) on inhaled gas absolute humidity in adults undergoing general anaesthesia. DESIGN: Systematic review and meta-analyses of randomised controlled trials. We defined FGF (l min) as minimal (0.25 to 0.5), low (0.6 to 1.0) or high (≥2). We extracted the inhaled gas absolute humidity data at 60 and 120 min after connection of the patient to the breathing circuit. The effect size is expressed as the mean differences and corresponding 95% confidence intervals (CI). DATA SOURCES: PubMed, EMBASE, SciELO, LILACS and CENTRAL until January 2017. RESULTS: We included 10 studies. The inhaled gas absolute humidity was higher with minimal flow compared with low flow at 120 min [mean differences 2.51 (95%CI: 0.32 to 4.70); P = 0.02] but not at 60 min [mean differences 2.95 (95%CI: -0.95 to 6.84); P = 0.14], and higher with low flow compared with high flow at 120 min [mean differences 7.19 (95%CI: 4.53 to 9.86); P < 0.001]. An inhaled gas absolute humidity minimum of 20 mgH2O l was attained with minimal flow at all times but not with low or high flows. An HME increased the inhaled gas absolute humidity: with minimal flow at 120 min [mean differences 8.49 (95%CI: 1.15 to 15.84); P = 0.02]; with low flow at 60 min [mean differences 9.87 (95%CI: 3.18 to 16.57); P = 0.04] and 120 min [mean differences 7.19 (95%CI: 3.29 to 11.10); P = 0.003]; and with high flow of 2 l min at 60 min [mean differences 6.46 (95%CI: 4.05 to 8.86); P < 0.001] and of 3 l min at 120 min [mean differences 12.18 (95%CI: 6.89 to 17.47); P < 0.001]. The inhaled gas absolute humidity data attained or were near 30 mgH2O l when an HME was used at all FGFs and times. CONCLUSION: All intubated patients should receive a HME with low or high flows. With minimal flow, a HME adds cost and is not needed to achieve an appropriate inhaled gas absolute humidity.

Anesthesia-Related and Perioperative Cardiac Arrest in Low- and High-Income Countries: A Systematic Review With Meta-Regression and Proportional Meta-Analysis.

The anesthesia-related cardiac arrest (CA) rate is a quality indicator to improve patient safety in the perioperative period. A systematic review with meta-analysis of the worldwide literature related to anesthesia-related CA rate has not yet been performed.This study aimed to analyze global data on anesthesia-related and perioperative CA rates according to country's Human Development Index (HDI) and by time. In addition, we compared the anesthesia-related and perioperative CA rates in low- and high-income countries in 2 time periods.A systematic review was performed using electronic databases to identify studies in which patients underwent anesthesia with anesthesia-related and/or perioperative CA rates. Meta-regression and proportional meta-analysis were performed with 95% confidence intervals (CIs) to evaluate global data on anesthesia-related and perioperative CA rates according to country's HDI and by time, and to compare the anesthesia-related and perioperative CA rates by country's HDI status (low HDI vs high HDI) and by time period (pre-1990s vs 1990s-2010s), respectively.Fifty-three studies from 21 countries assessing 11.9 million anesthetic administrations were included. Meta-regression showed that anesthesia-related (slope: -3.5729; 95% CI: -6.6306 to -0.5152; P = 0.024) and perioperative (slope: -2.4071; 95% CI: -4.0482 to -0.7659; P = 0.005) CA rates decreased with increasing HDI, but not with time. Meta-analysis showed per 10,000 anesthetics that anesthesia-related and perioperative CA rates declined in high HDI (2.3 [95% CI: 1.2-3.7] before the 1990s to 0.7 [95% CI: 0.5-1.0] in the 1990s-2010s, P < 0.001; and 8.1 [95% CI: 5.1-11.9] before the 1990s to 6.2 [95% CI: 5.1-7.4] in the 1990s-2010s, P < 0.001, respectively). In low-HDI countries, anesthesia-related CA rates did not alter significantly (9.2 [95% CI: 2.0-21.7] before the 1990s to 4.5 [95% CI: 2.4-7.2] in the 1990s-2010s, P = 0.14), whereas perioperative CA rates increased significantly (16.4 [95% CI: 1.5-47.1] before the 1990s to 19.9 [95% CI: 10.9-31.7] in the 1990s-2010s, P = 0.03).Both anesthesia-related and perioperative CA rates decrease with increasing HDI but not with time. There is a clear and consistent reduction in anesthesia-related and perioperative CA rates in high-HDI countries, but an increase in perioperative CA rates without significant alteration in the anesthesia-related CA rates in low-HDI countries comparing the 2 time periods.

Isoflurane and Propofol Contribute to Increasing the Antioxidant Status of Patients During Minor Elective Surgery: A Randomized Clinical Study.

Isoflurane is a volatile halogenated anesthetic used especially for anesthesia maintenance whereas propofol is a venous anesthetic utilized for anesthesia induction and maintenance, and reportedly an antioxidant. However, there are still controversies related to isoflurane-induced oxidative stress and it remains unanswered whether the antioxidant effects occur in patients under propofol anesthesia.Taking into account the importance of better understanding the role of anesthetics on oxidative stress in anesthetized patients, the present study was designed to evaluate general anesthesia maintained with isoflurane or propofol on antioxidant status in patients who underwent minimally invasive surgeries.We conducted a prospective randomized trial in 30 adult patients without comorbidities who underwent elective minor surgery (septoplasty) lasting at least 2 h admitted to a Brazilian tertiary hospital.The patients were randomly allocated into 2 groups, according to anesthesia maintenance (isoflurane, n = 15 or propofol, n = 15). Peripheral blood samples were drawn before anesthesia (baseline) and 2-h after anesthesia induction.The primary outcomes were to investigate the effect of either isoflurane or propofol anesthesia on aqueous plasma oxidizability and total antioxidant performance (TAP) by fluorometry as well as several individual antioxidants by high-performance liquid chromatography. As secondary outcome, oxidized genetic damage (7,8-dihydro-8-oxoguanine, known as 8-oxo-Gua) was investigated by the comet assay.Both anesthesia techniques (isoflurane or propofol) for a 2-h period resulted in a significant decrease of plasma α-tocopherol, but not other antioxidants including uric acid, carotenoids, and retinol (P > 0.05). Propofol, in contrast to isoflurane anesthesia, significantly increased (P < 0.001) anti-inflammatory/antioxidant plasma γ-tocopherol concentration in patients. Both anesthesia types significantly enhanced hydrophilic antioxidant capacity and TAP, with no significant difference between them, and 8-oxo-Gua remained unchanged during anesthesia in both groups. In addition, both anesthetics showed antioxidant capacity in vitro.This study shows that anesthesia maintained with either propofol or isoflurane increase both hydrophilic and total antioxidant capacity in plasma, but only propofol anesthesia increases plasma γ-tocopherol concentration. Additionally, both types of anesthetics do not lead to oxidative DNA damage in patients without comorbidities undergoing minimally invasive surgery.

Dexmedetomidine on renal ischemia-reperfusion injury in rats: assessment by means of NGAL and histology.

BACKGROUND: Ischemic acute kidney injury is a common occurrence in the perioperative period and in critical patients admitted to intensive care units. The reestablishment of blood supply may worsen injury through the ischemia-reperfusion (I/R) mechanism. We investigated the effect of dexmedetomidine on the kidneys of rats subjected to an experimental I/R model. METHODS: 34 rats anesthetized with isoflurane was undergone right nephrectomy and randomly assigned to four groups: Control C (saline solution); Dexmedetomidine D (dexmedetomidine); Sham S (saline solution); Sham with Dexmedetomidine SD (dexmedetomidine). The serum levels of neutrophil gelatinase-associated lipocalin (NGAL) were measured at time-points T1 (following stabilization), T2 (ischemia), T3 (reperfusion), T4 (12 h after of I/R). The kidneys were subjected to histological examination. RESULTS: The NGAL levels were significantly higher at T4 compared with T1. Upon histological examination, the left kidneys in groups C and D exhibited a similar extent of cell injury. CONCLUSION: The levels of NGAL did not indicate either protection against or worsening of kidney injury. Histological examination for acute tubular necrosis showed that dexmedetomidine did not protect the kidneys from I/R.

Pediatric perioperative cardiac arrest and mortality: a study from a tertiary teaching hospital.

OBJECTIVES: A previous survey performed in our institution demonstrated perioperative pediatric cardiac arrest and mortality rates of 22.9 and 9.8 per 10,000 anesthetics, respectively, and an anesthesia-related cardiac arrest rate of 4.58 per 10,000 anesthetics. Changes in pediatric practices (i.e., safer anesthesia techniques and change in population) may have altered cardiac arrest rates. The aim of this investigation was to reexamine the perioperative and anesthesia-related cardiac arrest rates, causes, and outcomes in a Brazilian institution. DESIGN: Observational study. SETTING: Tertiary teaching hospital. PATIENTS: Children less than 18 years old, who were administered an anesthetic between January 1, 2005, and December 31, 2010, were included in this study. The cardiac arrest cases were identified from an anesthesia database. The data included children's characteristics, surgical procedures, American Society of Anesthesiologists physical status classification, surgical areas, and surgery type. The outcomes were perioperative cardiac arrest and mortality and anesthesia-related (totally or partially) cardiac arrest and mortality. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: There were 10,649 anesthetics during the study period, with 22 perioperative cardiac arrests and 11 deaths (20.65 and 10.32 per 10,000 anesthetics, respectively). A high incidence of perioperative cardiac arrest occurred in American Society of Anesthesiologists IV-V neonates and infants who underwent emergency surgery. There were no perioperative cardiac arrests in children aged 13 through 17, no anesthesia-related cardiac arrest in American Society of Anesthesiologists I-III children, and no totally anesthesia-related cardiac arrest. The anesthesia-related cardiac arrest rate was 2.81 per 10,000 anesthetics, with no anesthesia-related mortality. Respiratory events accounted for all of the anesthesia-related cardiac arrests. CONCLUSIONS: Despite the improvements achieved in the pediatric anesthesia safety in our institution, the perioperative cardiac arrest rates are still high and similar to the developing countries rates, with the child's disease or condition being the most important trigger for cardiac arrest. Airway management continues to be the greatest cause of anesthesia-related cardiac arrest.

Intraoperative and anesthesia-related cardiac arrest and its mortality in older patients: a 15-year survey in a tertiary teaching hospital.

BACKGROUND: Little information is known about factors that influence perioperative and anesthesia-related cardiac arrest (CA) in older patients. This study evaluated the incidence, causes and outcome of intraoperative and anesthesia-related CA in older patients in a Brazilian teaching hospital between 1996 and 2010. METHODS: During the study, older patients received 18,367 anesthetics. Data collected included patient characteristics, surgical procedures, American Society of Anesthesiologists (ASA) physical status, anesthesia type, medical specialty team and outcome. All CAs were categorized by cause into one of four groups: patient's disease/condition-related, surgery-related, totally anesthesia-related or partially anesthesia-related. RESULTS: All intraoperative CAs and deaths rates are shown per 10,000 anesthetics. There were 100 CAs (54.44; 95% confidence intervals [CI]: 44.68-64.20) and 68 deaths (37.02; 95% CI: 27.56-46.48). The majority of CAs were patient's disease-/condition-related (43.5; 95% CI: 13.44-73.68). There were six anesthesia-related CAs (3.26; 95% CI: 0.65-5.87) - 1 totally and 5 partially anesthesia-related, and three deaths, all partially anesthesia-related (1.63; 95% CI: 0.0-3.47). ASA I-II physical status patients presented no anesthesia-related CA. Anesthesia-related CA, absent in the last five years of the study, was due to medication-/airway-related causes. ASA physical status was the most important predictor of CA (odds ratio: 14.52; 95% CI: 4.48-47.08; P<0.001) followed by emergency surgery (odds ratio: 8.07; 95% CI: 5.14-12.68; P<0.001). CONCLUSIONS: The study identified high incidence of intraoperative CAs with high mortality in older patients. The large majority of CAs were caused by factors not anesthesia-related. Anesthesia-related CA and mortality rates were 3.26 and 1.63 per 10,000 anesthetics, with no anesthesia-related CA in the last five years of the study. Major predictors of intraoperative CAs were poorer ASA physical status and emergency surgery. All anesthesia-related CAs were medication-related or airway-related, which is important for prevention strategies.

The humidity in a Dräger Primus anesthesia workstation using low or high fresh gas flow and with or without a heat and moisture exchanger in pediatric patients.

BACKGROUND: An inhaled gas absolute humidity of 20 mg H2O·L is the value most considered as the threshold necessary for preventing the deleterious effects of dry gas on the epithelium of the airways during anesthesia. Because children have small minute ventilation, we hypothesized that the humidification of a circle breathing system is lower in children compared with adults. The Primus anesthesia workstation (Dräger Medical, Lübeck, Germany) has a built-in hotplate to heat the patient's exhaled gases. A heat and moisture exchanger (HME) is a device that can be used to further humidify and heat the inhaled gases during anesthesia. To evaluate the humidifying properties of this circle breathing system during pediatric anesthesia, we compared the temperature and humidity of inhaled gases under low or high fresh gas flow (FGF) conditions and with or without an HME. METHODS: Forty children were randomly allocated into 4 groups according to the ventilation of their lungs by a circle breathing system in a Dräger Primus anesthesia workstation with low (1 L·min) or high (3 L·min) FGF without an HME (1L and 3L groups) or with an HME (Pall BB25FS, Pall Biomedical, East Hills, NY; HME1L and HME3L groups). The temperature and absolute humidity of inhaled gases were measured at 10, 20, 40, 60, and 80 minutes after connecting the patient to the breathing circuit. RESULTS: The mean inhaled gas temperature was higher in HME groups (HME1L: 30.3°C ± 1.1°C; HME3L: 29.3°C ± 1.2°C) compared with no-HME groups (1L: 27.0°C ± 1.2°C; 3L: 27.1°C ± 1.5°C; P < 0.0001). The mean inhaled gas absolute humidity was higher in HME than no-HME groups and higher in low-flow than high-flow groups ([HME1L: 25 ± 1 mg H2O·L] > [HME3L: 23 ± 2 mg H2O·L] > [1L: 17 ± 1 mg H2O·L] > [3L: 14 ± 1 mg H2O·L]; P < 0.0001). CONCLUSIONS: In a pediatric circle breathing system, the use of neither high nor low FGF provides the minimum humidity level of the inhaled gases thought to reduce the risk of dehydration of airways. Insertion of an HME increases the humidity and temperature of the inhaled gases, bringing them closer to physiological values. The use of a low FGF enhances the HME efficiency and consequently increases the inhaled gas humidity values. Therefore, the association of an HME with low FGF in the breathing circuit is the most efficient way to conserve the heat and the moisture of the inhaled gas during pediatric anesthesia.

Intraoperative cardiac arrest and mortality in trauma patients. A 14-yr survey from a Brazilian tertiary teaching hospital.

BACKGROUND: Little information on the factors influencing intraoperative cardiac arrest and its outcomes in trauma patients is available. This survey evaluated the associated factors and outcomes of intraoperative cardiac arrest in trauma patients in a Brazilian teaching hospital between 1996 and 2009. METHODS: Cardiac arrest during anesthesia in trauma patients was identified from an anesthesia database. The data collected included patient demographics, ASA physical status classification, anesthesia provider information, type of surgery, surgical areas and outcome. All intraoperative cardiac arrests and deaths in trauma patients were reviewed and grouped by associated factors and also analyzed as totally anesthesia-related, partially anesthesia-related, totally surgery-related or totally trauma patient condition-related. FINDINGS: Fifty-one cardiac arrests and 42 deaths occurred during anesthesia in trauma patients. They were associated with male patients (P<0.001) and young adults (18-35 years) (P=0.04) with ASA physical status IV or V (P<0.001) undergoing gastroenterological or multiclinical surgeries (P<0.001). Motor vehicle crashes and violence were the main causes of trauma (P<0.001). Uncontrolled hemorrhage or head injury were the most significant associated factors of intraoperative cardiac arrest and mortality (P<0.001). All cardiac arrests and deaths reported were totally related to trauma patient condition. CONCLUSIONS: Intraoperative cardiac arrest and mortality incidence was highest in male trauma patients at a younger age with poor clinical condition, mainly related to uncontrolled hemorrhage and head injury, resulted from motor vehicle accidents and violence.

Lower levels of oxidative DNA damage and apoptosis in lymphocytes from patients undergoing surgery with propofol anesthesia.

Propofol, which is widely used as an intravenous anesthetic, has a phenolic structure similar to that of α-tocopherol with antioxidant properties that could prevent genotoxicity and cytotoxicity in lymphocytes of anesthetized patients. The aims of this study were to evaluate oxidative DNA damage and apoptosis in lymphocytes and the expression of DNA repair genes in blood cells from patients undergoing elective surgery under anesthesia with propofol. Twenty healthy adults of both genders (18-50 years old) who were scheduled for otorhinological surgery were enrolled in this study. Blood samples were collected before anesthesia induction (T1-baseline), 120 min after anesthesia induction (T2), and on the first postoperative day (T3). Oxidative DNA damage in peripheral lymphocytes was assessed using the comet assay. Lymphocytes were phenotyped as T helper or cytotoxic T cells, and apoptosis was evaluated using flow cytometry. The expression of DNA repair genes (hOGG1 and XRCC1) was assessed by quantitative polymerase chain reaction. A reduction in the level of oxidized purines in DNA (P < 0.01) was observed 120 min after anesthesia induction, and reduced apoptosis of T helper cells was observed 120 min after anesthesia induction and on the first postoperative day. Down-regulation of hOGG1 and XRCC1 gene expression was observed on the first postoperative day. In conclusion, patients undergoing non-invasive surgery under propofol anesthesia presented lower levels of oxidized purines and apoptosis of T helper lymphocytes. Furthermore, anesthesia with propofol did not directly influence the expression of the DNA repair genes hOGG1 and XRCC1 in blood cells.

DNA damage in patients who underwent minimally invasive surgery under inhalation or intravenous anesthesia.

Recent studies have demonstrated the genotoxicity of anesthetics in patients who have undergone surgery and in personnel who are occupationally exposed to anesthetics. However, these findings are controversial. Herein, we used the comet assay (single-cell gel electrophoresis) to investigate the genotoxic effects of two volatile compounds [isoflurane (ISF) and sevoflurane (SVF)] that are used in inhalation anesthesia, and of one intravenous (iv) anesthetic compound [propofol (PF)]. The groups consisted of 45 patients who underwent minimally invasive surgery that lasted at least 2h. Patients were classified as physical status I using the criteria of the American Society of Anesthesiologists (ASA) and were randomly allocated to receive ISF, SVF or PF anesthesia. Venous blood samples were collected at three time points as follows: before the premedication and the induction of anesthesia (T(0)); 2h after the beginning of anesthesia (T(1)); and on the day following surgery (T(2)). DNA damage (strand breaks and alkali-labile sites) was evaluated in peripheral blood lymphocytes. For each patient, one hundred nucleoids were analyzed per time point using a semi-automated image system. Patients did not differ with respect to their demographic characteristics, the duration of surgery, or the total doses of intraoperative drugs. The amount of DNA damage was not different among the three groups before anesthesia (T(0)). No statistically significant (p>0.05) increase in DNA damage was detected during (T(1)) or after anesthesia (T(2)) using three different protocols (ISF, SVF or PF). In conclusion, general anesthesia with inhaled ISF and SVF or iv PF did not induce DNA strand breaks or alkali-labile sites in peripheral lymphocytes. Therefore, our results show that the genotoxic risk of these anesthetics, for healthy patients undergoing minimally invasive otorhinological surgery, is low or even absent.

The temperature and humidity in a low-flow anesthesia workstation with and without a heat and moisture exchanger.

BACKGROUND: The Dräger Primus anesthesia workstation has a built-in hotplate to heat the patient's exhaled gas. The fresh gas flow is mixed with the heated exhaled gas as they pass through the soda lime canister. A heat and moisture exchanger (HME) may also be used to further heat and humidify the inhaled gas. In this study we measured the temperature and humidity of the inhaled gas coming from the Dräger Primus with or without a HME. METHODS: Thirty female patients were randomly divided into 2 groups and their lungs ventilated by the Primus Dräger anesthesia workstation with or without a HME. The humidity and temperature of the inhaled gas were measured 15, 30, 60, 90, and 120 minutes after connecting the patient to the breathing circuit. RESULTS: After 120 minutes of ventilation with a low-flow breathing circuit, the temperatures of inhaled gas were 25°C ± 1°C and 30°C ± 2°C without and with HME, respectively, with a statistically significant difference between groups (P < 0.001) with 95% confidence interval (CI) of 3.80°C to 6.40°C; and the absolute humidity values of the inhaled gas were 20.5 ± 3.6 mgH(2)O · L(-1) and 30 ± 2 mgH(2)O · L(-1) without and with HME, respectively, with a statistically significant difference between groups (P < 0.001) with 95% CI of 7.37°C to 13.03°C. CONCLUSIONS: The Primus anesthesia workstation partially humidifies the inspired gas when a low fresh gas flow is used. Insertion of an HME increases the humidity in inhaled gas, bringing it close to physiological values.

The effects of 6% hydroxyethyl starch-hypertonic saline in resuscitation of dogs with hemorrhagic shock.

BACKGROUND: Hemodynamic and global oxygen transport variables have failed to reflect splanchnic hypoperfusion, resulting in a failure to recognize inadequately treated hemorrhagic shock. Volemic expansion after fluid resuscitation is essential to improve global and regional oxygen in hemorrhagic shock. We hypothesized that, in contrast to conventional plasma expanders, the smaller volemic expansion from 7.5 NaCl/6% hydroxyethyl starch (HHES) solution administration in hemorrhagic shock may provide lesser systemic oxygen delivery and gastric perfusion. We used hemorrhaged dogs to compare intravascular volume expansion and the early systemic oxygenation and gastric perfusion effects of fixed fluid bolus administration, which are usually used in clinical situations with severe hemorrhage, of HHES, lactated Ringer (LR), and 6% hydroxyethyl starch (HES) solutions. METHODS: Thirty dogs were bled (30 mL · kg(-1)) to hold mean arterial blood pressure at 40 to 50 mm Hg over 45 minutes and were resuscitated in 3 groups: LR (n = 10) at 3:1 ratio to shed blood; HES (mean molecular weight 130 kDa, degree of substitution 0.4) (n = 10) at 1:1 to shed blood; and HHES (n = 10), 4 mL · kg(-1). Intravascular volume expansion (Evans blue and hemoglobin dilution), hemodynamic, systemic oxygenation, venous-to-arterial CO(2) gradient (Pv-aCO(2)), and gastric intramucosal-arterial PCO(2) gradient (PCO(2) gap) variables were measured at baseline, after 45 minutes of hemorrhage, and 5, 45, and 90 minutes after fluid resuscitation. RESULTS: HHES increased blood volume because of the high volume expansion efficiency, but intravascular volume expansion with this solution was the smallest of the solutions (P < 0.05). All 3 solutions induced a similar hemodynamic performance but HHES showed lower mixed venous PO(2) and higher systemic oxygenation extraction, Pv-aCO(2), and PCO(2) gap than LR and HES (P < 0.05). CONCLUSIONS: In dogs submitted to pressure-guided hemorrhagic shock and fixed-volume resuscitation, the smaller intravascular volume expansion from HHES solutions provides worse recovery of systemic oxygenation and gastric perfusion compared with LR and HES solutions despite its high volume expansion efficiency, which was limited by low infused volume.

A study of the effect of hemorrhage on the cardiorespiratory actions of halothane, isoflurane and sevoflurane in the dog.

OBJECTIVE: To compare the cardiorespiratory changes induced by equipotent concentrations of halothane (HAL), isoflurane (ISO) and sevoflurane (SEVO) before and after hemorrhage. STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: Twenty-four healthy adult dogs weighing 15.4 +/- 3.4 kg (mean +/- SD). METHODS: Animals were randomly allocated to one of three groups (n = 8 per group). In each group, anesthesia was maintained with 1.5 minimum alveolar concentration of HAL (1.3%), ISO (1.9%) and SEVO (3.5%) in oxygen. Controlled ventilation was performed to maintain eucapnia. Cardiorespiratory variables were evaluated at baseline (between 60 and 90 minutes after induction), immediately after and 30 minutes after the withdrawal of 32 mL kg(-1) of blood (40% of the estimated blood volume) over a 30-minute period. RESULTS: During baseline conditions, ISO and SEVO resulted in higher cardiac index (CI) than HAL. Heart rates were higher with SEVO at baseline, while mean arterial pressure (MAP) and mean pulmonary arterial pressure did not differ between groups. Although heart rate values were higher for ISO and SEVO after hemorrhage, only ISO resulted in a higher CI when compared with HAL. In ISO-anesthetized dogs, MAP was higher immediately after hemorrhage, and this was related to better maintenance of CI and to an increase in systemic vascular resistance index from baseline. CONCLUSIONS: Although the hemodynamic responses of ISO and SEVO are similar in normovolaemic dogs, ISO results in better maintenance of circulatory function during the early period following a massive blood loss. CLINICAL RELEVANCE: Inhaled anesthetics should be used judiciously in animals presented with blood loss. However, if an inhalational agent is to be used under these circumstances, ISO may provide better hemodynamic stability than SEVO or HAL.

Complicações das vias aéreas relacionadas à intubação endotraqueal / Airway complications associated with endotracheal intubation

Descrevemos as principais complicações das vias aéreas relacionadas à intubação endotraqueal, por meio de revisão da literatura e apresentação dos resultados de pesquisas clínicas e experimentais realizadas pelo nosso grupo de estudo. Procuramos alertar os profissionais de saúde quanto à alta incidência de complicações secundárias à intubação, as quais podem ser reduzidas com a adoção de medidas profiláticas simples e de cunho prático, estabelecidas após a compreensão da fisiopatologia das lesões.