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.

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.

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.

Comparison of peri-operative core temperature in obese and non-obese patients.

Our aim was to compare peri-operative core temperatures and the incidence of hypothermia in obese and non-obese women with active forced-air warming. Twenty female patients scheduled for abdominal surgery were allocated to two groups according to body mass index. Ten obese (30.0-34.9 kg.m(-2) ) and 10 non-obese (18.5-24.9 kg.m(-2) ) women received forced-air warming on their lower limbs. At the end of surgery, the mean (SD) core temperatures were 36.7 (0.5) °C in the obese group and 36.0 (0.6) °C in the non-obese group (p < 0.001). Only in the non-obese group was there a significant decrease in the intra-operative core temperature values (p < 0.001). The incidences of intra-operative hypothermia were lower in the obese group (10%) compared with non-obese group (60%; p = 0.019). In the postoperative recovery phase, the mean (SD) core temperature data were higher in the obese group than in the non-obese group (36.2 (0.4) vs 35.6 (0.5) °C, respectively (p < 0.001)). In conclusion, obese female patients have higher peri-operative core temperature and a lower incidence of hypothermia compared with non-obese female patients during abdominal surgery with active forced-air warming.

Remifentanil, isoflurane, and preconditioning attenuate renal ischemia/reperfusion injury in rats.

BACKGROUND: The purpose of this investigation was to examine the effect of isoflurane, remifentanil, and preconditioning in renal ischemia/reperfusion injury (IRI). METHODS: All 52 male Wistar rats were anesthetized with isoflurane, intubated and mechanically ventilated. The animals were randomly divided into: S group (sham; n = 11) that underwent only right nephrectomy; as well as the I group of right nephrectomy and ischemia for 45 minutes by clamping of left renal artery. (n = 11); the IP (n = 9), the R (n = 10), and the RP (n = 11) groups. In addition, the R and RP animals received remifentanil (2 microg.kg(-1).min(-1)) during the entire experiment. The IP and RP group underwent ischemic preconditioning (IPC = three cycles of 5 minutes). Serum creatinine values were determined before and after IRI, as well as 24 hours later. In addition to an Histological study, cells from the left kidney were evaluated for apoptosis by flow cytometry (FCM). RESULTS: The Creatinine value of 0.8 +/- 0.2 mg/dl in the S group was significantly lower at 24 hours than the I 3.9 +/- 1.5 mg/dl; IP 2.6 +/- 1.7 mg/dl; R 3.3 +/- 2.8 mg/dl; or RP 1.8 +/- 0.5 mg/dl groups. The RP group value was significantly lower than those of the I, IP, and R groups (p < 0.05). The S group showed less proximal tubular cell damage than the I, IP, R, and RP groups (p < 0.05). The percentages of apoptotic cells (FITC(+)/PI(-)) were: S group = 11.6 +/- 6.5; I = 16.7 +/- 7.3; IP = 37.0 +/- 28.4; R = 11.7 +/- 6.6, and RP = 8.8 +/- 1.5. The difference between the IP vs RP group was significant. Similar percentages of necrotic cells (FITC(+)/PI(+)) and intact cells (FITC(-)/PI(-)) were observed among the groups. CONCLUSIONS: Ischemic preconditioning showed no protective effect in the isoflurane group (IP) but when isoflurane was administered associated with remifentanil (RP), there was a beneficial effect on the kidney, as demonstrated by flow cytometry and serum creatinine values.

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.

High laryngeal mask airway pressures resulting from nitrous oxide do not increase pharyngeal mucosal injury in dogs.

PURPOSE: During general anesthesia, nitrous oxide (N2O) diffuses rapidly into the air-filled laryngeal mask airway (LMA) cuff, increasing intracuff pressure. There is no clear correlation between LMA intracuff pressure and pressure on the pharynx. We have studied the effects of high LMA intracuff pressures secondary to N2O on the pharyngeal mucosa of dogs. METHODS: Sixteen mongrel dogs were randomly allocated to two groups: G1 (intracuff volume, 30 mL; n=8) breathed a mixture of O2 (l L x min(-1)) and air (l L x min(-1)) and G2 (intracuff volume, 30 mL; n=8) a mixture of O2 (l L x min(-1)) and N2O (l L x min(-1)). Anesthesia was induced and maintained with pentobarbitone. LMA cuff pressure was measured at zero (control), 30, 60, 90 and 120 min after #4 LMA insertion. The dogs were sacrificed, and biopsy specimens from seven predetermined areas of the pharynx in contact with the LMA cuff were collected for light (LM) and scanning electron microscopic (SEM) examination by a blinded observer. RESULTS: LMA intracuff pressure decreased with time in G1 (P <0.001) and increased in G2 (P <0.001). There was a significant difference between the groups (P <0.001). In both groups, the LM study showed a normal epithelium covering the pharyngeal mucosa and mild congestion in the subepithelial layer. There were no differences between the groups (P >0.10) or among the areas sampled (P >0.05). In both groups, the SEM study showed a normal pharyngeal mucosa with mild superficial desquamation. Few specimens in G1 and G2 showed more intense epithelial desquamation. CONCLUSION: High LMA intracuff pressures produced by N2O do not increase pharyngeal mucosal injury in dogs.

Acute renal ischemia model in dogs: effects of metoprolol.

INTRODUCTION: To study the functional and histological alterations in dog kidneys submitted to total ischemia for thirty minutes and the possible metoprolol protective action. MATERIAL AND METHODS: Sixteen dogs anesthetized with sodium pentobarbital (SP) were studied and divided into two groups: G1-8 dogs submitted to left nephrectomy and right renal artery clamping for thirty minutes, and G2-8 dogs submitted to the same procedures of G1 and to the administration of 0.5 mg x kg(-1) metoprolol before ischemia. Attributes of renal function were studied. RESULTS: There was acute tubular necrosis and a decrease of renal blood flow and glomerular filtration, and a increase of renal vascular resistance in both groups. CONCLUSION: The thirty minute renal ischemia appears to have determined the alterations found in the renal function and histology in both groups. Metoprolol, used in G2, as to the time and dose applied didn't protect the kidney from the ischemic episode.

Effect of high laryngeal mask airway intracuff pressure on the laryngopharyngeal mucosa of dogs.

OBJECTIVES: To evaluate the effect of increased of laryngeal mask airway (LMA) intracuff pressures on the laryngopharyngeal mucosa. STUDY DESIGN: Animal model. METHODS: Sixteen mixed-breed dogs were randomly allocated to two groups, G1 (intracuff volume, 30 mL; n = 8) and G2 (intracuff volume, 54 mL; n = 8), to produce, respectively, high or very high intracuff pressures. Anesthesia was induced and maintained with pentobarbital. Intracuff pressures were measured immediately after insertion and inflation of a No. 4 laryngeal mask airway (LMA) and 30, 60, 90, and 120 minutes thereafter. The dogs were euthanized, and biopsy specimens from eight predetermined areas of the laryngopharynx in contact with LMA cuff were collected for light microscopic (LM) and scanning electron microscopic (SEM) examination. RESULTS: Initial LMA cuff inflation in G1 and G2 resulted in intracuff pressures of 119 mm Hg +/- 4 mm Hg and 235 mm Hg +/- 13 mm Hg, respectively. Over a 2-hour period, the intracuff pressure decreased significantly in G1 (P < .001) and G2 (P < .01), and there was a significant difference between the groups over time (P < .001). The LM study of laryngopharyngeal mucosa in both groups showed mild congestion in the subepithelial layer. There were no differences between the groups (P > .10) or among the areas sampled (P > .10). In some areas of G2, the SEM study showed epithelial desquamation that was more intense than that in G1. CONCLUSIONS: The increase in LMA intracuff pressure caused only mild alterations in the laryngopharyngeal mucosa of the dog.

Investigation into the use of the laryngeal mask airway in pentobarbital anesthetized dogs.

OBJECTIVE: To investigate the use of the laryngeal mask airway (LMA) in dogs. STUDY DESIGN: Prospective experimental study. ANIMALS: Eight healthy adult mixed breed dogs weighing from 15 to 20 kg. METHODS: The dogs were anesthetized with intravenous pentobarbital. An LMA was introduced after the induction of anesthesia and 1 L/min O2 plus 1 L/min air was delivered using a circle anesthetic system. Respiratory rate, tidal volume, arterial O2 saturation (pulse oximetry), end tidal CO2, inspired fraction of O2, pulse rate, and mean arterial blood pressure were measured after the insertion of the LMA and 30, 60, 90, and 120 minutes afterwards. RESULTS: There were no changes in respiratory rate, tidal volume, arterial O2 saturation, and pulse rate during anesthesia. End tidal CO2 decreased significantly by the end of anesthesia and ventilation appeared satisfactory. CONCLUSIONS: An LMA appeared to be an alternative option to maintain the patency of the airway in dogs. CLINICAL RELEVANCE: This device may allow safe maintenance of an airway in dogs when intubation is difficult or when it interferes with the procedure (eg, cervical myelography).

Tracheobronchial consequences of the use of heat and moisture exchangers in dogs.

PURPOSE: To determine the effect of heat and moisture exchange (HME) on the tracheobronchial tree (TBT) using a unidirectional anesthesic circuit with or without CO2 absorber and high or low fresh gas flow (FGF), in dogs. METHODS: Thirty-two dogs were randomly allocated to four groups: G1 (n=8) valvular circuit without CO2 absorber and high FGF (5 L x min(-1)); G2 (n=8) as G1 with HME; G3 (n=8) circuit with CO2 absorber with a low FGF (1 L x min(-1)); G4 (n=8) as G3 with HME. Anesthesia was induced and maintained with pentobarbital. Tympanic temperature (TT), inhaled gas temperature (IGT), relative (RH) and absolute humidity (AH) of inhaled gas were measured at 15 (control), 60, 120 and 180 min of controlled ventilation. Dogs were euthanized and biopsies in the areas of TBT were performed by scanning electron microscopy. RESULTS: The G2 and G4 groups showed the highest AH (>20 mgH2O x L(-1)) and G1 the lowest (< 10 mgH2O x L(-1)) and G3 was intermediate (< 20 mgH2O x L(-1)) (P < 0.01). There was no difference of TT and IGT among groups. Alterations of the mucociliary system were greatest in G1, least in G2 and G4, and intermediate in G3. CONCLUSION: In dogs, introduction of HME to a unidirectional anesthetic circuit with/without CO2 absorber and high or low FGF preserved humidity of inspired gases. HME attenuated but did not prevent alterations of the mucociliary system of the TBT.

Endotracheal tube cuff pressure: need for precise measurement.

CONTEXT: High compliance endotracheal tubes cuffs are used to prevent gas leak and also pulmonary aspiration in mechanically ventilated patients. However, the use of the usual cuff inflation volumes may cause tracheal damage. OBJECTIVE: We tested the hypothesis that endotracheal tube cuff pressures are routinely high (above 40 cmH2O) in the Post Anesthesia Care Unit (PACU) or Intensive Care Units (ICU). DESIGN: Cross-sectional study. SETTING: Post anesthesia care unit and intensive care unit. PARTICIPANTS: We measured endotracheal tubes cuff pressure in 85 adult patients, as follows: G1 (n = 31) patients from the ICU; G2 (n = 32) patients from the PACU, after anesthesia with nitrous oxide; G3 (n = 22) patients from the PACU, after anesthesia without nitrous oxide. Intracuff pressure was measured using a manometer (Mallinckrodt, USA). Gas was removed as necessary to adjust cuff pressure to 30 cmH2O. MAIN MEASUREMENTS: Endotracheal tube cuff pressure. RESULTS: High cuff pressure (> 40 cmH2O) was observed in 90.6% patients of G2, 54.8% of G1 and 45.4% of G3 (P < 0.001). The volume removed from the cuff in G2 was higher than G3 (P < 0.05). CONCLUSION: Endotracheal tubes cuff pressures in ICU and PACU are routinely high and significant higher when nitrous oxide is used. Endotracheal tubes cuff pressure should be routinely measured to minimize tracheal trauma.

Sympathetic hyperactivity, respiratory failure, pruritus, and anesthesia after unintentional epidural injection of potassium chloride: case report.

BACKGROUND AND OBJECTIVES: A combination of epidural and general anesthesia has been widely used to attenuate the surgical stress response and to provide postoperative analgesia. This case report illustrates the use of this anesthetic technique. Analgesia was induced with local anesthetic in the immediate postoperative period using unintentional 19.1% potassium chloride (KCl) as diluent. METHODS: An ASA I male patient was scheduled for surgical correction of idiopathic megaesophagus under continuous epidural anesthesia combined with general anesthesia. In the postoperative period, while preparing 10 mL 0.125% bupivacaine to be administered through the epidural catheter for pain control, 5 mL 19.1% KCl was unintentionally used as diluent, resulting in a 9.55% potassium solution concentration. RESULTS: The patient developed warmness of the lower limbs, tachycardia, hypertension, intense pruritus on the chest, agitation, exacerbation of sensory and motor blocks, and respiratory failure secondary to pulmonary edema, requiring ventilatory support. Total recovery was observed after 24 hours. CONCLUSIONS: Epidurally injected potassium leads to severe clinical manifestations caused by autonomic dysfunction, spinal cord irritation, and possible release of histamine. Despite continuous recommendations, ampule misidentification still happens in hospitals, frequently leading to serious accidents.

Effect of high-dose fentanyl on renal function in dogs.

Our objective was to determine the effects of high-dose fentanyl on canine renal function (RF). We anesthetized with sodium pentobarbital (SP) 16 dogs, randomly divided into 2 groups: in G1, SP was given alone, and in G2, combined with 0.05 mg.kg-1 fentanyl. All animals were ventilated artificially and had catheterized left and right femoral veins and left femoral artery for fluid infusion, drug administration, blood collection, and hemodynamic measurement. Urine was collected throughout the experiment. Attributes of RF were studied. SP did not alter RF, which was significantly altered by fentanyl. In G2, slower heart rates, mean arterial pressure, creatinine clearance, urinary output, osmolar clearance and fractional excretion of sodium and potassium were observed. G1 had a behavior attributed to extracellular volume expansion and no RF alterations. In G2, we observed significant decreases in RF due to opioid-induced hemodynamic changes, not discarding the possible action of aldosterone.