Longer Duration Of Anesthesia Research Articles

Post Cardiopulmonary Bypass Changes in Liver Function: Comment on "J Cardiovasc Thorac Res 2015;7:49-54".

This study examines abnormal LFT (mainly bilirubin) on postoperative day three as a predictor of open cardiac surgery mortality.1 Preoperative hyperbilirubinemia, high right atrial pressure, number of heart valves replaced and high blood transfusion requirements are risk factors predicting postoperative hyperbilirubinemia in 81% of all patients.2 This study strictly excluded high-risk conditions to cleverly evaluate the isolated and subtle liver injuries occurring post-cardiopulmonary bypass (CPB). As a result, 200 out of 400 patients originally enrolled were excluded which can lead to not sampling naturally distributed population. Most studies defined hyperbilirubinemia as total bilirubin >2 mg/dL for preoperative and >3 for postoperative whereas cut off was 1.5 mg/dl in this study.2,3 The effects of diabetes (which causes direct hyperbilirubinemia) and BMI status on liver function are unknown.4 The study examined excreting function of liver only (bilirubin), but neither synthetic (INR, albumin) nor metabolic (mono-ethyl glycine xylidide) markers of liver function were not measured.5 All CPB operations were on pump, with none-pulsatile perfusion, average amount of blood transfusion (no autologous blood) with systemic hypothermia of 28°C. Results showed minimal increase in TB by 0.2 mg/dl (mainly direct bilirubin), AST and ALP on postoperative day three. These changes mostly occurred in patients with preoperative hyperbilirubinemia, which was consistent with other studies.2 Transient benign increase in LFT can occur post CPB. Hyperbilirubinemia could be related to undetected RV failure, undetected preoperative hyperbilirubinemia and prolonged intraoperative hypotension (multiple etiologies possible). The study excluded patients with overt preoperative congestive heart failure, but did not measure intraoperative central filling pressures. Some patients had preoperative hyperbilirubinemia of unknown etiology. Prolonged intraoperative hypotension could occur due to multiple reasons including perioperative myocardial infarction, hypovolemia, low cardiac output, lower pump flow of non-pulsatile CPB and prolonged CPB time. Hyperbilirubinemia of 2.5 and >3.7 on post-op day two and seven, respectively, were predictors of the mortality in other studies.2,6 These studies included high-risk patients including cardiac valve replacement. Of four mortalities reported, two were due to liver failure with total bilirubin >24 on seventh postoperative day and two others died of multi-organ failure. Among the patients with cardiac transplant, the mortality was 25% in patients with postoperative total bilirubin > 2.8 mg/dL which was much greater than 4.3% in patients with a total bilirubin between 1.4 and 2.8 mg/dL. Additionally, two year post-CPB survival decreased by 1.7 fold vs. 3.8 fold with postoperative total bilirubin of 1.4-2.8 vs. >2.8, respectively.7 As the mortality data were not included, it was difficult to conclude whether hyperbilirubinemia on the third postoperative day could serve as the single strong predictor of jaundice-related mortality. A relatively lower incidence was reported for jaundice and that was probably probably due to healthy patient selection. Yet, the reported mortality due to liver failure among the jaundiced patients was significantly higher than that reported by others. Higher transfusion requirement (>6 units), possibility of infection along with the above mentioned factors could be contributing. Pump time was 100 minutes. Pump time >70 min associated with post-op hyperbilirubinemia; >120 minutes associated with high mortality.5,8 Hypothermia benefits were lost due to intraoperative hypotension and longer duration of anesthesia. Hyperbilirubinemia on post op day three should be aggressively investigated and treated. Anatomically suitable patients may benefit from off-pump cardiac surgery and coronary grafting.9

Effects of fondaparinux on pulmonary embolism following hemiarthroplasty for femoral neck fracture: a retrospective observational study using the Japanese Diagnosis Procedure Combination database

Pulmonary embolism (PE) is recognized as an important complication in patients undergoing hip fracture surgery. However, clinical evidence demonstrating the effectiveness of pharmacological thromboprophylaxis, including fondaparinux, is limited because the occurrence of postoperative PE after hemiarthroplasty is very low. The goal of this study was to analyze the effect of fondaparinux in reducing PE following hemiarthroplasty for femoral neck fracture using large-scale retrospective data. Employing data from the Japanese Diagnosis Procedure Combination database from July 1 to December 31 between 2007 and 2010, we retrospectively identified 22,776 patients who underwent hemiarthroplasty for femoral neck fracture; we included those who received mechanical prophylaxis alone (n = 17,984) and those who received both mechanical prophylaxis and pharmacological prophylaxis with fondaparinux (n = 4,792). Logistic regression analysis was performed to compare the occurrence of postoperative PE with adjustment for sex, age, comorbidities, and type and duration of anesthesia. The mean age of the patients was 79.5 ± 9.4 years. Overall, postoperative PE occurred in 189 (0.83%) patients. The rate of postoperative PE in the fondaparinux group (0.61%) was lower than in the control group (0.89%), although the difference was not significant in the univariate analysis (odds ratio [OR] 0.68; p = 0.055). In the multivariate analysis, the fondaparinux group showed a significantly lower rate of postoperative PE than the group receiving mechanical prophylaxis alone (OR 0.67; p = 0.047). General anesthesia and a longer duration of anesthesia were significant risk factors for postoperative PE. Fondaparinux combined with mechanical prophylaxis is more effective in preventing postoperative PE following hemiarthroplasty for femoral neck fracture than mechanical prophylaxis alone.

The incidence and risk factors of gastrointestinal complications after hepatectomy: a retrospective observational study of 1329 consecutive patients in a single center

BackgroundDespite of the importance of gastrointestinal (GI) complications in morbidity and mortality after major and moderate surgeries, it is not yet specifically studied in patients undergoing hepatectomy. This study was aimed to investigate the in-hospital incidence and potential risk factors of GI complications after open hepatectomy in our hospital. Subjects and methodsProspectively recorded perioperative data from 1329 patients undergoing elective hepatectomy were retrospectively reviewed. The in-hospital incidence of GI complications was investigated, and independent risk factors were analyzed by multiple logistic regression. ResultsGI complications occurrence was 46.4%. Univariate analysis showed that preoperative Child-Pugh score, total bilirubin, aspartate transaminase, anesthesia duration, operation duration, intraoperative blood loss, crystalloid and colloid infusion, blood transfusion, urine output, use of Pringle maneuver were statistically different between patients with and without GI complications (P < 0.05). Moreover, patients with GI complications had a more prolonged postoperative parenteral nutrient supporting time, hospital stay and ICU stay, and higher incidence of other complications than those without GI complications (P < 0.05). Multivariate regression indicated that long duration of anesthesia (odds ratio 2.51, P < 0.001) and use of Pringle maneuver (odds ratio 1.37, P = 0.007) were independent risk factors of GI complications after hepatectomy. ConclusionsThe incidence of GI complications after hepatectomy is high, which is related to an increase of other complications and a prolonged hospital stay. Avoidance of routinely use of Pringle maneuver and shortening the duration of anesthesia are important measures to reduce the postoperative GI complications.

Clinical features and outcome of super-refractory status epilepticus: A retrospective analysis in West China

PurposeData about super-refractory status epilepticus (SRSE) are scarce. This study aimed to assess the clinical features and outcome of patients with SRSE. MethodClinical features of all SRSE patients admitted to the Neurologic Intensive Care Unit (NICU)/Neurology Department of West China Hospital, Sichuan University, between January 2010 and August 2013, were retrospectively analyzed. Outcome at discharge, at the three-month and long-term follow-ups were evaluated using the Glasgow Outcome Scale (GOS). Possible predictors of mortality and outcome were also evaluated. ResultsThirteen patients with SRSE were included. Young patients with encephalitis accounted for the majority of the series (61.5%). In-hospital mortality was 15.4% (2/13), and the three-month mortality was 36.4% (4/11; two patients ceasing therapy were excluded). At the long-term follow-up, 18.2% of patients improved and 45.5% of patients recovered. Patients of older age and those with multiple complications had higher mortality compared with those of younger age and those with fewer complications. For survivors, functional outcome had significantly improved at three-month follow-up (GOS score=4.1±1.2) compared to that at discharge (GOS score=3.1±1.2, P<0.05). Long duration of anesthesia, etiology of encephalitis and positive neuroimaging findings tended to be associated with poor functional outcome. ConclusionWe conclude that the typical patient susceptible to development of SRSE in West China is a young patient with encephalitis. Older age and multiple complications increase the risk of death. Most patients can survive with aggressive therapy, and their functional outcome improves over time.

Incidence and risk factors of postoperative nausea and vomiting in patients with fentanyl-based intravenous patient-controlled analgesia and single antiemetic prophylaxis.

PurposeWe evaluated the incidence and risk factors of postoperative nausea and vomiting (PONV) in patients with fentanyl-based intravenous patient-controlled analgesia (IV-PCA) and single antiemetic prophylaxis of 5-hydroxytryptamine type 3 (5 HT3)-receptor antagonist after the general anesthesia.Materials and MethodsIn this retrospective study, incidence and risk factors for PONV were evaluated with fentanyl IV-PCA during postoperative 48 hours after various surgeries.ResultsFour hundred-forty patients (23%) of 1878 had showed PONV. PCA was discontinued temporarily in 268 patients (14%), mostly due to PONV (88% of 268 patients). In multivariate analysis, female, non-smoker, history of motion sickness or PONV, long duration of anesthesia (>180 min), use of desflurane and intraoperative remifentanil infusion were independent risk factors for PONV. If one, two, three, four, five, or six of these risk factors were present, the incidences of PONV were 18%, 19%, 22%, 31%, 42%, or 50%. Laparoscopic surgery and higher dose of fentanyl were not risk factors for PONV.ConclusionDespite antiemetic prophylaxis with 5 HT3-receptor antagonist, 23% of patients with fentanyl-based IV-PCA after general anesthesia showed PONV. Long duration of anesthesia and use of desflurane were identified as risk factors, in addition to risk factors of Apfel's score (female, non-smoker, history of motion sickness or PONV). Also, intraoperative remifentanil infusion was risk factor independent of postoperative opioid use. As the incidence of PONV was up to 50% according to the number of risk factors, risk-adapted, multimodal or combination therapy should be applied.

Factors affecting anesthetic complications in children undergoing congenital cardiac catheterization

Background Anesthetic complications are among the most common adverse effects in congenital cardiac catheterization. Although the presence of an expert pediatric anesthetist will markedly reduce these complications, other factors may contribute toward their development. Objectives To determine the factors associated with the development of anesthetic complications in children undergoing congenital cardiac catheterization. Materials and Methods We carried out a prospective study of 71 patients who underwent cardiac catheterization over a period of 6 months and analyzed the intracatheterization and postcatheterization anesthetic complications. Results The most common anesthetic complication was delayed recovery (11.3%). Other less common adverse events included postoperative vomiting (2.8%), sinus tachycardia (2.8%), postoperative agitation (1.4%), intraoperative arousal (1.4%), and intraoperative apnea (1.4%). Patients who had no anesthetic adverse events were significantly older and had higher body weight compared with those who had one or more anesthetic problems. In addition, patients who had anesthetic adverse events had significantly longer procedure time compared with those who had no anesthetic complications. Conclusion Factors that can contribute toward anesthetic adverse events in children undergoing cardiac catheterization include a longer procedure time, longer duration of anesthesia, and younger age.

The effects of subarachnoid administration of hyperbaric solutions of bupivacaine or ropivacaine in xylazine-sedated calves undergoing surgery

The aim of this study was to compare the effects of subarachnoid administration of hyperbaric solutions of bupivacaine or ropivacaine in xylazine-sedated calves undergoing surgery. Subarachnoid anaesthesia was performed with...

Acute anemia and cardiovascular events after vascular surgery

Introduction: Anemia is a risk factor for cardiovascular complications in vascular surgery and we believe that the acute loss of hemoglobin may be more important than the baseline level. The purpose of this study is to evaluate the relationship between perioperative hemoglobin values and Cardiovascular Events (CVE). Methods: Prospective data were collected from 285 patients scheduled for elective vascular surgery. Cardiac risk was estimated according to the American College of Physicians algorithm and patients were monitored for CVE during hospitalization, with daily troponin T, CKMB, hemoglobin and eletrocardiogram until the 3rd post-operative day, repeated as needed. The degree of acute anemia was measured as the lowest hemoglobin value after surgery (nadir Hb), post-operative Hb below 9g/dL and Hb delta (pre-operative – post-operative Hb) during the first week. Results: In total, 286 patients were submitted to the planned surgery (72% men, 66.8yrs) and 45 (15.7%) had an event: 12 myocardial infarctions, 2 unstable anginas, 15 isolated troponin elevations; 11 ischemic strokes and 5 cardiac deaths. Preoperative anemia was present in 25.5% but baseline hemoglobin level was not associated to CVE. In the univariate analysis we found that coronary artery disease, intraoperative haemodynamic instability, blood transfusion, longer duration of anesthesia and the degree of acute anemia, were all associated to CVE. In the logistic regression model, the degree of acute anemia persisted significantly associated to CVE and patients with a post-operative hemoglobin under 9g/dL had more than twice the risk of events when compared to patients with hemoglobin above or equal to 9g/dL (OR: 2.30; CI 1.07 – 4.96; P=0.03). The other independent predictors of CV event were intraoperative haemodynamic instability (OR 4.62; CI: 2.12- 10.06; P<.000) and coronary artery disease (OR 2.55; CI: 1.17 -5.52; P=0.018). When we performed the same multivariate model for the 202 patients that did not receive blood transfusion, the putative effect of acute anemia was even greater (OR 3.90; CI: 1.30 -11.71; P=0.015). We also found that in 78.9% of our patients who had myocardial infarction, unstable angina or CV death, the gap between the CV event and the nadir Hb value was lower than 24hrs. Conclusion: The degree of acute anemia appears to be more important than the isolated preoperative value toward the occurrence of CVE. Blood transfusion therapy should be individualized and considered a mitigating factor.

Kısırlaştırılmış Dişi Köpeklerde Fenilbutazon ve Thiopental Sodyum Etkileşimi: Anesteziden Çıkışa Etkisi

Summary Anesthesia often involves administration of several drugs from different classes. Drug–drug interactions may affect the duration of action of anesthetic agents. The purpose of this research was to investigate interaction between phenylbutazone and thiopental sodium in dogs. Twenty-six female stray dogs were randomly divided into two groups. Each group subdivided into two subgroups <18kg and ≥18kg. Equivalent doses of thiopental sodium were intravenously administered following the injection of 0.9% normal saline in control group and phenylbutazone via the same route in experimental group. After anesthesia, time intervals needed for the return of palpebral reflex, opening of eyes, tongue movement, stretching of limbs, head and neck movements, sitting position, trying to stand, imbalanced walking and normal walking were recorded. Results showed the average time periods in the experimental group were generally more than those in the control group. It was shown the duration of the above chronological parameters were significantly higher in heavier dogs compared to the lighter. Females generally have a larger proportion of body fat content than males. This may cause a higher volume of distribution and a longer elimination half-life for thiopental in female dogs. This interaction with phenylbutazone may be due to an increase in the unbound form of thiopental sodium and its quicker distribution into the brain and a longer duration of anesthesia.

Onset, duration and efficacy of four methods of local anesthesia of the horn bud in calves

ObjectiveTo determine the onset, duration and efficacy of four local anesthetic methods for the horn bud in calves. Study designCrossover study. AnimalsEight, 2 month-old Holstein Friesian bull calves. MethodsCalves were subjected to one of the four following treatments: 1) cornual nerve block (C), 2) ring block (R), 3) cornual nerve block using a percutaneous jet delivery technique (JET) all using 2% lidocaine with epinephrine (0.01 mg mL−1), and 4) topical eutectic mixture of local anesthetics (EMLA) cream. A peripheral nerve stimulator was used to assess cutaneous sensation over the horn bud using a graded response. Onset, duration and efficacy of anesthesia were determined. ResultsThe efficacy of the blocks was as follows: C 87.5%, R 100%, JET 37.5%, EMLA 0%. The median onset time and duration of anesthesia for C and R were: 2 (range 0.5–5) and 304 (range 107–512), and 3.25 (range 1–9) and 147 (range 62–299) minutes, respectively. Three of eight JET injections had a median onset and duration of 8 (range 0.5–9) and 132 (range 101–155) minutes, respectively. The duration of the C block was significantly longer than the R block (p= 0.047). Conclusions and clinical relevanceThe relatively rapid onset and long duration of anesthesia with C or R blocks using 2% lidocaine with epinephrine validates their practical use in dehorning calves while jet injection and EMLA cream provided insufficient analgesia to be clinically useful. The efficacy of the C block requires further study.

Comparative Study of 4% Articaine with 1:100,000 Adrenaline and 2% Lidocaine with 1:100,000 Adrenaline for Anesthetizing the Lingual, Oral and Labial Mucosas of the Mandible

Objetivo: Comparar a efetividade da Articaina e da Lidocaina em tecnica de anestesia infiltrativa supraperiostea em vestibulo bucal da mandibula em relacao a capacidade de insensibilizacao das mucosas lingual, jugal e labial. Metodo: O estudo foi classificado como duplo cego, cruzado e randomizado, onde foram selecionados 30 pacientes adultos, separados aleatoriamente por um primeiro examinador que marcou na ficha o numero 1 ou 2 correspondendo as solucoes anestesicas. O segundo examinador anestesiou de acordo com o numero e a seguir o terceiro examinador realizou os testes de sensibilidade atraves do teste pin-prick e a escala analogica visual de dor (EVA) nas mucosas lingual, jugal e labial. Apos anestesiado, a duracao da anestesia foi observada pelos mesmos testes no intervalo de 10 em 10 minutos. Na semana seguinte foram realizados os mesmos procedimentos com o outro anestesico de acordo com o grupo ao qual o paciente pertenceu. Os dados foram submetidos ao teste T-student (p<0,05). Resultados: Houve diferenca estatistica significante a favor da articaina em relacao a insensibilizacao das mucosas lingual e labial, assim como na duracao total de anestesia nas mucosas. Em relacao a mucosa jugal, nao houve diferenca estatistica significante entre as drogas Conclusao: A articaina apresentou melhores propriedades que a lidocaina, como melhor difusibilidade, menor tempo de latencia e maior duracao de anestesia. O estudo mostrou que pela infiltracao por bucal na mandibula, a articaina apresenta difusibilidade capaz de insensibilizar as mucosas lingual, jugal e labial, o que mostra ser possivel a realizacao de procedimentos localizados em pequenas regioes da mandibula pela tecnica infiltrativa.

Efficacy of tramadol as analgesic and mixed with ketamine, xylazine as anesthetic in rabbits

This study were performed to evaluate the efficacy of Tramadol as analgesic and efficacy of using Tramadol in combination with other drugs like Ketamine and Xylazine in anesthetic protocols in rabbits. 15 adult New Zealand white rabbits divided to 3 equal groups were anesthetized intramuscularly in one syringe, group 1 with Tramadol 15 mg/kg B.W, group 2 with Tramadol 15mg/Kg B.W and Ketamine 30mg/Kg B.W, group 3 with Tramadol 15mg/Kg B.W and Ketamine 30mg/Kg B.W and Xylazine 5mg/Kg B.W, physiologic parameters were evaluated including : body temperature, heart rate, respiratory rate, muscle relaxation, analgesia and stages of anesthesia ( Induction of anesthesia, surgical anesthesia and recovery time).The most significant changes were reported in G3 (T15K30X5) and this combination is useful regimen clinically for anesthetize rabbits due to the fast of induction anesthesia and the long surgical duration of anesthesia.

Fetal Anesthesia and Brain Development

Professor of Clinical Anesthesiology, Columbia University, New York, New York. Pdf3@columbia.eduPRECLINICAL studies in neonatal mice, rats, piglets, and primates have shown that exposure to a variety of clinically used general anesthetic and sedative drugs causes widespread age-dependent neurodegeneration that is associated with learning deficits. These findings have created enormous anxiety among anesthesiologists, parents, and other practitioners about the safety of general anesthesia for young children. Little is known about the long-term effects of general anesthesia on the fetus. In this issue of Anesthesiology, Palanisamy and colleagues show that exposure of fetal rats in utero to 4 h of isoflurane at gestational age 14 days (roughly equivalent to second trimester in humans) leads to impaired spatial memory acquisition and perhaps greater impulsivity in young adulthood.1Epidemiologic studies have not provided a clear picture as to whether toxicity seen after anesthetizing young mammals is relevant to human development.2,3Further studies are being designed and conducted using epidemiologic and case-control methodologies to determine whether a signal for harm can be detected in humans. Previous investigators have questioned whether the relatively long duration of anesthesia in animals studies are relevant to the human gestation; the same issues potentially apply to this study. In this study, the authors treated dams with isoflurane for 4 h. Four hours of isoflurane anesthesia accounts for a much larger portion of the gestation than a 4-h anesthetic administered to a human mother–fetus pair. Whereas frank neuronal apoptosis appears to take hours to develop in animal models, exposure of neonatal rodents to volatile anesthetics causes increases in dendritic spine density in as little as 30 min, that persist for up to 4 weeks.4It is not known whether these increases in spine density are translated into temporary or permanent behavioral deficits, but there is need for further study.Rats have relatively brief focused brain development, and it is hard to superimpose changes induced by a single anesthetic onto the long, more gradual development of the human brain. However, a previous study in guinea pigs,5an animal with more gradual brain development, has shown that a 4-h exposure to isoflurane at the period of peak synaptogenesis induces neuroapoptosis. Behavior was not evaluated in that study, and histopathology was not done in the current study. Studies that incorporate parallel measures of histopathology and behavior are particularly informative in this respect.These findings should concern but not alarm the obstetrical anesthesia community. The current study1and the previous study in guinea pigs5both used isoflurane as a test agent. However, this presumably is a class effect related to potentiation of γ-aminobutyric acid receptor activity, because all volatile anesthetics, propofol, and midazolam have been shown to be neurotoxic in studies on infant mammals. However, it is not clear which anesthetic technique might be least toxic, nor has any general anesthetic agent been convincingly shown to be more toxic. Elective surgery is not conducted during pregnancy. Most women who undergo general anesthesia during pregnancy do so to address a medical issue critical to their well-being or that of their fetus. Regional anesthesia has always been preferred during pregnancy predominantly because of concerns about the maternal airway and with the very theoretical consideration of exposing the fetus to fewer medications. Of course, it is not feasible to conduct some types of necessary surgery under regional anesthesia.Concern about anesthesia exposure at delivery is at least reduced by recent epidemiologic studies of mothers exposed to regional and general anesthesia during vaginal and cesarean delivery whose children did not show an increased incidence of learning disabilities compared with those unexposed.2,6,7However, the risk in nonhuman mammals is timing and exposure dependent. The possibility remains that longer exposures at different gestational ages might be more, or less, toxic. This question will be tricky to answer with epidemiologic studies, because it would not be surprising if fetuses that require surgery are at higher risk for learning disabilities than the general population or if severe maternal illness that requires surgery is a risk factor in development. Surgery itself causes inflammation that can induce changes in the central nervous system. These questions can not be ethically addressed with a randomized controlled trial. As we await clarity, certainly nonurgent surgery should continue to be postponed until after pregnancy. These concerns should be added to the other risks and benefits in determining anesthetic technique used in a pregnant woman. Consideration should be made to using regional anesthesia when possible.Professor of Clinical Anesthesiology, Columbia University, New York, New York. Pdf3@columbia.edu

Caudal epidural injection of lidocaine, tramadol, and lidocaine–tramadol for epidural anesthesia in cattle

Caudal epidural anesthesia is commonly utilized in veterinary medicine to allow diagnostic, obstetrical, and surgical intervention, in the perineal region of large animal. The aim of this study is to directly compare the time of onset and duration of analgesia produced by a tramadol and lidocaine-tramadol combination with that produced by lidocaine administration in the epidural space of Cattle. Five healthy adult Holstein dairy cows were selected to this study. Epidural anesthesia was produced in all cows by lidocaine, with 2 weeks intervals repeated by a combination of lidocaine-tramadol and tramadol. Time to onset and duration of analgesia were recorded. Heart rate, respiratory rate and body temperature were recorded at 0 min and at 5, 10, 15, 30, 60, and 75 min after the epidural administrations of each treatments. The tramadol produced a significant (P < 0.05) longer duration of analgesia (306.8 ± 8.58 min) than lidocaine (69.40 ± 8.96 min) alone and lidocaine-tramadol combination (174 ± 4.84 min). Also, lidocaine-tramadol combination produced a significant (P < 0.05) longer duration of analgesia than lidocaine alone. Complete analgesia began at 14.10 ± 1.57 min in the tramadol treatment, being more delayed than in the treatments with lidocaine-tramadol (4.84 ± 0.68 min) and lidocaine (3.90 ± 0.89 min). Body temperatures, heart rates, and respiratory rates were not significantly different in comparison with baseline values throughout the study in the all treatments. The combination of lidocaine-tramadol produced anesthesia of longer duration than lidocaine and the onset time was approximately same as for the lidocaine group. Utilizing this combination, long duration of anesthesia could commence relatively soon after epidural injection and might be used without re-administration of anesthetic agent in long-duration obstetrical and surgical procedures.

Anesthetic Efficacy of Articaine and Lidocaine for Incisive/Mental Nerve Block

Introduction The incisive/mental nerve block (IMNB) could be an alternative to the inferior alveolar nerve block in the mandibular anterior teeth. The effectiveness of articaine has not been tested in IMNB. Methods This prospective randomized double-blind crossover study compared the anesthetic efficacy of 0.6 mL 4% articaine and 2% lidocaine, both with 1:100.000 epinephrine administered as IMNB to 40 volunteers in two sessions. Pulpal anesthesia of lateral incisor through premolars was tested with an electric pulp tester. The injection and postoperative pain were evaluated by using visual analog scales. The onset (time from the end of injection to the absence of pulpal response) and duration of pulpal anesthesia (time recorded before two positive responses to the pulp tester) and the anesthesia success (two consecutive readings of 80 without response and onset ≤10 minutes) were measured. Results Articaine provided a higher success rate ( p < 0.001) of anesthesia than lidocaine for the lateral incisor (32.5%), the canine (55%), and the first (72.5%) and second (80%) premolars and a faster onset ( p < 0.05) for canine and increased duration ( p < 0.05) of anesthesia for premolars. The median duration of premolars anesthesia was 10 and 20 minutes, respectively, with lidocaine and articaine. There were no differences in pain scores between the solutions ( p > 0.05). Conclusions Articaine promoted higher anesthesia success and longer duration of anesthesia than lidocaine for most of the teeth after IMNB although anesthesia success could be considered clinically appropriated only for premolars. The volume of local anesthetic used in the present study may not be appropriate for procedures lasting longer than 10 minutes.

Risk factors for colic in horses after general anaesthesia for MRI or nonabdominal surgery: absence of evidence of effect from perianaesthetic morphine

Post anaesthetic colic is a recognised risk of general anaesthesia (GA), but causes are poorly understood. To identify risk factors for development of colic following GA for magnetic resonance imaging (MRI) or nonabdominal surgery and to test whether the use of perianaesthetic morphine was associated with an increased risk of post anaesthetic colic. A total of 553 anaesthetic and clinical records of 500 horses anaesthetised at the Animal Health Trust were analysed, 342 (62%) involved MRI and 211 (38%) nonabdominal, predominantly orthopaedic surgery. Multivariable logistic regression analysis was used to examine the association between post anaesthetic colic and explanatory variables, including use of perianaesthetic morphine. Twenty horses (3.6%) developed colic within 7 days of GA. A significantly larger (P = 0.001) proportion of the surgical cases developed post anaesthetic colic (7.1%) compared with MRI cases (1.5%). Having controlled for the effect of MRI/surgeon, there was evidence for a significantly increased risk of colic associated with maintenance of anaesthesia with isoflurane and administration of benzyl penicillin and/or ceftiofur. A reduction in risk of colic was associated with premedication with romifidine, longer duration of anaesthesia and sedation within 2 days of GA. Perianaesthetic morphine administration was not associated with increased risk. This study identified apparently novel risk factors for colic in horses following GA. Use of morphine was not found, after controlling for other MRI and surgery related risk factors, to be associated with an increased risk. The low prevalence of colic after GA and resulting low study power mean that further larger, multicentre collaborative studies are warranted to corroborate findings in this study. Better knowledge of risk factors should lead to achievable measures to reduce frequency of occurrence.

Perioperative Hypothermia in the Pediatric Population: Prevalence, Risk Factors and Outcomes

Background: Perioperative hypothermia has been associated with negative outcomes, and children may be at higher risk. This study describes the prevalence of pediatric perioperative hypothermia and evaluates its relationship to outcomes. Methods: This observational cohort study included the following electronically and prospectively recorded data from children fewer than 18 years of age undergoing general anesthesia: perioperative temperatures, warming interventions, patient characteristics, and surgical procedures, duration of anesthesia and perioperative outcomes. Intraoperative hypothermia was defi ned as temperature (T) < 36°C for at least fi ve minutes, and postoperative hypothermia as any T<36°C. Results: Of the 530 patients studied, 278 (52%) experienced intraoperative hypothermia. Invasive procedures and skin probe monitoring were associated with intraoperative hypothermia. In children with core T monitoring undergoing invasive procedures, older age, longer duration of anesthesia, greater blood loss and blood transfusion were associated with hypothermia. Warming interventions is used in most hypothermic children during operation, but in few in the post- anesthesia care unit (PACU). T was re-assessed in <6% of children who were hypothermic in the PACU. Conclusions: This study found a high prevalence of hypothermia and use of intraoperative warming techniques. Hypothermia was more common in older children and in those undergoing longer, invasive procedures and was associated with greater blood loss and blood transfusion.

Incidence of and risk factors for postoperative pneumonia in dogs anesthetized for diagnosis or treatment of intervertebral disk disease

To determine incidence of and risk factors for postoperative pneumonia in dogs anesthetized for diagnosis or treatment of intervertebral disk disease (IVDD). Retrospective case-control study. 707 dogs that underwent general anesthesia for the diagnosis or treatment of IVDD between 1992 and 1996 or between 2002 and 2006. Postoperative pneumonia was diagnosed if compatible clinical signs (cough or hypoxemia) and radiographic abnormalities (alveolar infiltrates) developed within 48 hours after anesthesia. To identify risk factors for postoperative pneumonia, findings for dogs that developed postoperative pneumonia between 2002 and 2006 were compared with findings for a randomly selected control group of unaffected dogs from the same population. There were no significant differences in age, breed, body weight, sex, location of IVDD, or survival rate between the 2 time periods, but there were significant differences in the use of magnetic resonance imaging, computed tomography, and hemilaminectomy and in the percentage of dogs that developed postoperative pneumonia in the later (4.6%) versus the earlier (0.6%) years. Significant risk factors for postoperative pneumonia included preanesthetic tetraparesis, cervical lesions, undergoing magnetic resonance imaging, undergoing > 1 anesthetic procedure, longer duration of anesthesia, and postanesthetic vomiting or regurgitation. Results suggested that at this institution, the incidence of postoperative pneumonia in dogs anesthetized for diagnosis or treatment of IVDD had increased in recent years.

Risk factors for severe postoperative nausea and vomiting in a randomized trial of nitrous oxide-based vs nitrous oxide-free anaesthesia

BackgroundRefractory postoperative nausea and vomiting (PONV) requiring repeated treatment with antiemetic drugs is a miserable experience for the patient that may substantially increase the cost of care. As risk stratification may aid in prophylaxis and treatment, we explored risk factors for severe PONV in patients enrolled in a large international, randomized controlled trial (the ENIGMA trial). MethodsTwo thousand and fifty patients, aged ≥18 yr and undergoing surgery anticipated to exceed 2 h in duration, were recruited. Patients were randomized to nitrous oxide (N2O)-based or N2O-free anaesthesia. Choice of other anaesthetic, analgesic, and antiemetic drugs was left to the discretion of the anaesthetist. Anaesthetic depth was adjusted according to clinical judgement and, if available, bispectral index (BIS) monitoring. Severe PONV was defined as: (i) two or more episodes of expulsion of gastric contents at least 6 h apart; (ii) received at least three doses of antiemetic medication for treatment of PONV, within 24 h of surgery; or both. We used logistic regression, and classification and regression tree analysis, to define risk factors for severe PONV. ResultsThree hundred and thirty-three (16.6%) patients experienced severe PONV. Age <55 yr, female sex, abdominal surgery, N2O administration, absence of BIS monitoring, and longer duration of anaesthesia were predictors of severe PONV [area under receiver operating characteristic curve=0.70 (95% confidence interval: 0.67–0.73)]. ConclusionsSevere PONV was common and risk factors for it were similar to those reported in other studies that included all patients reporting nausea, vomiting, or both.

Effect of nitrous oxide on plasma homocysteine and folate in patients undergoing major surgery

BackgroundNitrous oxide (N2O) inhibits methionine synthetase resulting in elevated plasma homocysteine (Hcy) concentration after surgery. In epidemiological studies, hyperhomocysteinaemia is associated with increased risk of cardiovascular disease and dementia. MethodsBlood samples were obtained to measure plasma folate and Hcy concentrations from two centres participating in a multicentre randomized trial investigating the effects of N2O on the outcome after major surgery. The effect of N2O and duration of anaesthesia on plasma Hcy, and the relationship between hyperhomocysteinaemia and outcomes were assessed. ResultsWe enrolled 394 patients. The N2O Group had an increase in plasma Hcy concentration after surgery when compared with the N2O-free Group: 11.1 (3.8) vs 8.5 (4.0) μmol litre−1, P<0.0005. Postoperative hyperhomocysteinaemia was associated with an increased risk of major complications: risk ratio (RR) 2.8 (95% CI: 1.4–5.4), P=0.002 and cardiovascular events, RR 5.1 (95% CI: 3.1–8.5), P<0.0005. There was a significant association between duration of anaesthesia and the relative change in plasma Hcy concentration, particularly in the N2O Group: r=0.42, P<0.001. ConclusionsN2O increases plasma Hcy concentration; this effect is greater with a longer duration of anaesthesia. Hyperhomocysteinaemia is a risk factor for major postoperative complications. N2O-induced increases in plasma Hcy concentration may be a cause of postoperative cardiovascular morbidity.