Longer Immediate Recovery Time After Anesthesia Increases Risk of Respiratory Complications After Laparotomy for Bariatric Surgery: a Randomized Clinical Trial and a Cohort Study.

BACKGROUND: We compared the effects of two anesthesia protocols in both immediate recovery time (IRT) and postoperative respiratory complications (PRCs) after laparotomy for bariatric surgery, and we determined the association between the longer IRT and the increase of PRC incidence. METHODS: We conducted the study in two stages: (i) in a randomized controlled trial (RCT), patients received either intervention (sevoflurane-remifentanil-rocuronium-ropivacaine) or control protocol (isoflurane-sufentanil-atracurium-levobupivacaine). All patients received general anesthesia plus continuous epidural anesthesia and analgesia. Treatment was masked for all, except the provider anesthesiologist. We defined IRT as time since anesthetics discontinuation until tracheal extubation. Primary outcomes were IRT and PRCs incidence within 15 days after surgery. We also analyzed post-anesthesia care unit (PACU) and hospital length of stays; (ii) after the end of the RCT, we used the available data in an extension cohort study to investigate IRT > 20 min as exposure factor for PRCs. RESULTS: Control protocol (n = 152) resulted in longer IRT (30.4 ± 7.9 vs 18.2 ± 9.6 min; p < 0.0001), higher incidence of PRCs (6.58 vs 2.5 %; p = 0.048), and longer PACU and hospital stays than intervention protocol (n = 200); PRC relative risk (RR) = 2.6. Patients with IRT > 20 min (n = 190) presented higher incidence of PRCs (7.37 vs 0.62 %; p < 0.0001); RR = 12.06. CONCLUSIONS: Intervention protocol, with short-acting anesthetics, was more beneficial and safe compared to control protocol, with long-acting drugs, regarding the reduction of IRT, PRCs, and PACU and hospital stays for laparotomy in bariatric patients. We identified a 4.5-fold increase in the relative risk of PRCs when morbid obese patients are exposed to an IRT > 20 min.

Ischemic Postconditioning and Subanesthetic S(+)-Ketamine Infusion: Effects on Renal Function and Histology in Rats.

BACKGROUND: Ischemic postconditioning (IP) in renal Ischemia reperfusion injury (IRI) models improves renal function after IRI. Ketamine affords significant benefits against IRI-induced acute kidney injury (AKI). The present study investigated the effects of IP and IP associated with subanesthetic S(+)-ketamine in ischemia-reperfusion-induced AKI. METHODS: Forty-one Wistar rats were randomized into four groups: CG (10), control; KG (10), S(+)-ketamine infusion; IPG (10), IP; and KIPG (11), S(+)-ketamine infusion + IP. All rats underwent right nephrectomy. IRI and IP were induced only in IPG and KIPG by left kidney arterial occlusion for 30 min followed by reperfusion for 24 h. Complete reperfusion was preceded by three cycles of 2 min of reocclusion followed by 2 min of reperfusion. Renal function was assessed by measuring serum neutrophil gelatinase-associated lipocalin (NGAL), creatinine, and blood urea nitrogen (BUN). Tubular damage was evaluated by renal histology. RESULTS: Creatinine and BUN were significantly increased. Severe tubular injury was only observed in the groups with IRI (IPG and KIPG), whereas no injury was observed in CG or KG. No significant differences were detected between IPG and KIPG. CONCLUSIONS: No synergic effect of the use of subanesthetic S(+)-ketamine and IP on AKI was observed in this rat model.

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.

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.

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.

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.

Efeitos do sulfato de magnésio na hemodinâmica cardiovascular de cåes anestesiados com pentobarbital sódico / Effects of magnesium sulphate on the cardiovascular hemodynamics of dogs anesthetized pentobarbitone

Background and Objectives - A controversy exists in the literature regarding the effects of the acute administration of magnesium on the cardiovascular system of animals and humans. The purpose of this study was to evaluate the effects of hypermagnesemia on the cardiovascular hemodynamics of dogs. Methods - Sixteen mongrel dogs were anesthtized with pentobarbitone 30mg.kg-1 and submitted to volume expansion with Ringer's solution (0.4ml.kg-1.min-1) and mechanical ventilation with room air. In this model, the hemodynamic repercussions of the following drugs and doses were studied: pentobarbitone 5mg,kg-1 - Group 1, control - and the association of pentobarbitone and magnesium sulphate (MS), at the dose of 140 mg.kg-1, injected in 15 minutes, followed by an infusion of 80 mg.kg-1.h-1 - Group 2. The parameters studied were: heart rate, blood pressure, inferior vena cava pressure, cardiac index, systolic index and peripheral resistance index, evaluated at 5 different moments: 15(M1), 30(M2), 60(M3) and 75(M4) minutes after the first supplementary dose of pentobarbitone and 15 minutes (M5) after the second supplementary dose. In group 2, the moments M3, M4, M5 corresponded to 15, 30 and 60 minutes after the priming dose of magnesium sulphate. Results - Group 1 animals exhibited tachycardia since the beginning of the experiment. There was a decrease in the cardiac index, in the systolic index and an increase in the inferior vena cava pressure. group 2 animals also exhibited tachycardia, but heart rate decreased after MS infusion. The blood pressure and the peripheralresitance index decreased. The systolic index increased and the cardiac index decresead only at he end of the experiment. Conclusions - The antiadrenergic effects of Ms could have been responsible for the decrease in heart rate. The vasodilating effects of the magnesium induced the decrease in the peripheral resistance index. The vasodilating effects of the magnesium induced the decrease in the peripheral resistance index. The systolic index increased, showing that myocardial depression did not occur.

Sufentanil intranasal como medicaçäo pré-anestésica em crianças / Intranasal sufentanil as preanesthetic medication in children

Justificativas e objetivos - Dentre as diferentes vias utilizadas para administracao da medicacao pre-anestesica (MPA), a via intranasal oferece a vantagem da rapida absorcao sistemica, alem de evitar as dolorosas injecoes intramuscular e nevosa. O presente estudo tem como objetivo avaliar a eficacia do sufentanil como MPA na reducao da ansiedade dos pacientes pediatricos, assim como no comportamento dos memos durante a inducao anestesica. Metodo - Participaram do estudo trinta pacientes com idade de 1 a 9 anos, ASA 1, submetidos a cirurgias eletivas, que receberam sufentanil (2 mug.kg(-1) por via intransal como MPA. Utilizando-se o grau de ansiedade em 3 momentos: T0 - chegada da crianca com os pais; T5 e T10, respectivamente, cinco e dez minutos apos a administracao da droga. Avaliou-se tambem o comportamento durante a inducao. Todas as inducoes anestesicas foram venosas, utilizando-se tiopental ou cetamina. Resultados - O grau de ansiedade nao diminuiu dez minutos apos a administracao do sufentanil e nao se observou melhora na qualidade da inducao anestesica. Conclusoes - O sufentanil intranasal, nas doses empregadas neste estudo, nao mostrou ser eficiente na reducao da ansiedade nem melhorou a qualidade da inducao anestesica, quando o tempo entre a administracao da droga e a separacao dos pais foi de apenas dez minutos.

Efeitos do fentanil sobre a adrenalina e noradrenalina plasmáticos e do miocárdio: estudo experimental no cäo / Effects of fentanyl on plasma adrenaline and noradrenaline and of the myocardium: experimental study in dogs

Estudou-se em 24 cäes os efeitos do pentobarbital sódico (30mg.kg*-1 de peso corpóreo) e do Fentanil (0,005; 0,05 e 0,1mg.kg*-1 de peso corpóreo) sobre as catecolaminas plasmáticas e do miocárdio. O estudo foi complementado com determinaçöes da pressäo arterial média, da freqüência cardíaca, da pressäo venosa da cava inferior, do hematócrito, da temperatura retal, do pHa, da PaO2 e da PaCO2. Os resultados obtidos demonstraram que 1) O pentobarbital sódico determinou boa estabilidade dos atributos cardiocirculatórios e sanguíneos estudados; 2) O Fentanil em pequenas doses (0,005mg.kg*-1) näo alterou os níveis da adrenalina plasmática e da noradrenalina miocárdica e determinou queda pouco acentuada da pressäo arterial média e da freqüência cardíaca; 3) O Fentanil em grandes doses (0,005 e 0,1mg.kg*-1) näo alterou os níveis da adrenalina e noradrenalina plasmática, mas diminuiu significativamente a pressäo arterial média e a freqüência cardíaca

Estudo comparativo do diazepam e do lorazepam, via oral, associados à meperidina na medicaçäo pré-anestésica / Comparative study of diazepam and lorazepam, oral way, associated to meperidine in pre-anesthetic medication

Os benzodiazepínicos säo muito empregados em medicaçäo pré-anestésica por serem sedativos e ansiolíticos, induzirem amnésia, produzirem boa estabilidade cardiovascular e poderem ser administrados por várias vias. Em estudo duplo cego, 50 adultos, submetidos a anestesia geral ou epidural, foram pré-medicados com diazepam, 10mg (25 pacientes) ou lorazepam, 2 mg (25 pacientes), por via oral, na noite precedente à anestesia e 120 minutos antes do início da mesma. Para potencializar sua sedaçäo e para fins analgésicos foi-lhes associada a meperidina. Assim, a ambos os grupos administraram-se 2mg.Kg**-1 de meperidina (nunca excedendo 100mg), por via intramuscular, 60 minutos antes do início da anestesia. Quando utilizados separadamente, os dois benzodiazepínicos evidenciaram a mesma capacidade de sedaçäo. A associaçäo com a meperidina aumentou a sedaçäo apenas do grupo do diazepam. No grupo que recebeu lorazepam, observou-se maior induçäo de amnésia anterógrada

Bloqueio subaracnóideo com bupivacaína pesada a 0,5%: efeitos da adiçäo de adrenalina / Subarachnoid block with 0,5% bupivacaine: effects of adrenaline addiction

Estudaram-se em 48 pacientes os efeitos da bupivacaína pesada a 0,5% (15mg) associada ou näo à adrenalina 1:1.000(0,2mg) no bloqueio subaracnóideo. Os atributos estudados foram tempo de início do bloqueio sensitivo, tempo de latência, altura do bloqueio analgésico, grau do bloqueio motor, grau do relaxamento muscular, tempos de início da regressäo do bloqueio motor e de regressäo do bloqueio analgésico em 2, 4 e 6 metâmeros. Os valores da pressäo arterial e da freqüência de pulso completaram o estudo. Os resultados obtidos com os bloqueios realizados com a associaçäo bupivacaína-adrenalina, em comparaçäo com os realizados apenas com a bupivacaína, mostraram diminuiçäo significante dos tempos de início do bloqueio sensitivo (47%) e de latência (20%) e aumento, também significativo, dos tempos de início da regressäo do bloqueio motor (50%) e do bloqueio analgésico em 2(15%), 4(17,5%) e 6 metâmeros (19%). Quanto aos demais atributos, näo houve diferença significativa nos grupos estudados

Estudo multicêntrico aberto, näo comparativo, com etomidato em procedimentos cirúrgicos de curta duraçäo / Open multicenter study, non-comparative, with etomidate in short-term surgical procedures

Realizou-se um estudo multicêntrico em 155 pacientes de ambos os sexos, ASA 1, 2, e 3, submetidos a anestesia venosa com etomidato (0,3 mg.k-1) para procedimentos cirúrgicos de curta duraçäo. Foram administrados, como medicaçäo pré-anestésica, 10 minutos antes da induçäo, 100 micron-grama de fentanil por via venosa. Ao final do procedimento anestésico, verificou-se aumento das pressöes sistólica e diastólica, enquanto que a freqüência cardíaca manteve-se estável. A freqüência respiratória apresentou aumento, porém sem significado clínico. Em 113 pacientes (72,9%) houve necessidade de se administrar doses complementares da droga. O tempo médio de perda da consciência foi de 48 + ou - 22s do início da injeçäo. O tempo de recuperaçäo da consciência foi de 8,26 + ou - 5,16 min. A média do tempo para possível alta hospitalar foi de 61,7 + ou - 30,5 min. Com relaçäo aos efeitos secundários observou-se que em 15 (9,7%) pacientes houve dor no local da injeçäo, em 79 (51%) surgiram mioclonias, na maioria das vezes de grau leve, e em 36 (23,2%) pacientes ocorreu ereçäo pilosa. Concluíram ser o etomidato uma droga adequada para uso venoso em procedimentos de curta duraçäo

Custo das anestesias em um hospital universitário / Anesthesia cost in an university hospital

Em 633 anestesias do tipo geral inalatória com respiraçäo assistida e controlada, geral venosa, raquianestesia, peridural lombar e epidural sacra, foi avaliado o custo médio/hora de anestesia. A peridural lombar e a raquianestesia evidenciaram-se como as técnicas anestésicas mais econômicas, seguidas pela epidural sacra, e pelas gerais inalatórias. A anestesia geral venosa foi a de maior custo

Efeitos da hipotensäo arterial induzida pelo nitroprussiato de sódio sobre o equilíbrio hidroeletrolítico em cäes / Effects of the arterial hypotension induced by sodium nitroprusside on hydroelectrolyte balance in dogs

A funçäo renal vista sob aspecto referente ao equilíbrio hidroelectrolítico foi estudada durante hipotensäo arterial induzida pelo nitroprussiato de sódio (NPS) em 12 cäes, anestesiados com pentobarbital sódico e submetidos a ventilaçäo controlada (RPPI) com ar ambiente. Os animais foram divididos em dois grupos experimentais a saber: G1 -controle e G2 -animais tratados com NPS. Cada parâmetro foi avaliado em quatro momentos. O momento inicial (M1) serviu como controle, o momento final (M4) teve o objetivo de verificar se o animal retornava às condiçöes iniciais do experimento e os momentos intermédios (M2 e M3) onde se analisaram os efeitos do tratamento imposto. Os parâmetros analisados foram: volume urinário (Uv), osmolaridade plasmática (Posm), osmolaridade urinária (Uosm), depuraçäo osmolar (Cosm), depuraçäo de água livre (CH2O), sódio plasmático (PNa+), sódio urinário (UNa+), excreçäo urinário de sódio (UNa + V), excreçäo fracionária de sódio (EFNa +), depuraçäo de sódio (CNa +), reabsorçäo de sódio (RNa +), potássio plasmático (PK +), potássio (UK +), excrevaçäo urinária de potássio (UK + V), excreçäo fracionária de potássio (EFK +) e depuraçäo de potássio (CK +). É discutida a fisiopatologia das alteraçöes observadas. Os autores concluem que a hipotensäo arterial conseqüente à infusäo de NPS causou alteraçöes muito importantes em praticamente todos os parâmetros estudados

Hipotensäo arterial induzida e equilíbrio ácido-básico: estudo experimental no cäo / Induced arterial hypotension and acid-base balance: experimental study in dogs

Foram estudados, em cäes, os efeitos da hipotensäo arterial induzida pelo nitroprussiato de sódio sobre o equilíbrio ácido-básico. Em 12 cäes foram analisados a pressäo arterial média, o bicarbonato plasmático, o bicarbonato urinário, a reabsorçäo de bicarbonato, o pH do sangue arterial e as pressöes parciais de O2 e CO2 na urina. Estes atributos foram estudados em 4 momentos correspondendo M1 ao período de controle inicial; M2 e M3, respectivamente, a 30 e 60 minutos após o início do tratamento e M4 a 30 minutos após a suspensäo do tratamento. Os resultados demonstraram alteraçöes significativas nos níveis de bicarbonato plasmático e urinário, na reabsorçäo de bicarbonato e no pH do sangue arterial, sendo evidente o agravamento das condiçöes do equilíbrio ácido-básico com o transcorrer do experimento. É ainda discutida a fisiopatologia das alteraçöes observvadas nos atributos analisados

O ensino de anestesiologia na Faculdade de Medicina de Botucatu - UNESP / The anesthesiology education in the Faculdade de Medicina de Botucatu - UNESP

Faz-se um pequeno histórico da evoluçäo do ensino de Anestesiologia para o Curso de Graduaçäo da Faculdade de Medicina de Botucatu. Discorre-se sobre os critérios estabelecidos para a formaçäo do médico generalista. É demonstrado de forma detalhada o plano de ensino com seu conteúdo programático, sua carga horária e seus critérios de avaliaçäo

Efeitos do óxido nitroso em normoxia e hiperoxia sobre e funçäo renal do cäo / Effects of hyperoxic and normoxic nitrous oxide on renal function in the dog

Em 18 cäes, com anestesia de base pelo pentobarbital sódico (30 mg. kg-1) e submetidos à expansäo do volume extracelular (18 ml. kg-1 h-1), foi estudada a açäo do óxido nitroso em concentraçöes a 50 e 66% com o oxigênio (hiperoxia) e a 80% com o oxigênio (normoxia), sobre a funçäo renal. Foram analisados os seguintes parâmetros: fluxo plasmático efetivo renal, filtraçäo glomerular, depuraçäo osmolar, fraçäo de filtraçäo, fluxo sangüíneo renal, resistência vascular renal, volume urinário, osmolaridade urinária e excreçöes urinárias e fracionária de sódio. O estudo foi complementado com determinaçöes das pressöes arterial média e venosa da cava caudal da freqüência cardíaca do pHa e da PaO2 e PaCO2. O óxido nitroso em hiperoxia diminuiu significantemente os fluxos plasmáticos e sangüíneo renais, a filtraçäo glomerular, a excreçäo urinária de sódio e aumentou significantemente a resistência vascular renal e a pressäo arterial média. Em normoxia, o óxido nitroso näo alterou as depuraçöes de PAH e creatinina, o fluxo sangüíneo renal e as excreçöes urinárias e fracionárias de sódio, apesar de aumentar a pressäo arterial média e elevar, näo significantemente, a resistência vascular renal. Com base nos resultados obtidos, conclui-se que o óxido nitroso a 50 ou 60% com o oxigênio (hiperoxia) apresenta comportamento que o inclui entre os anestésicos que determinam alteraçöes renais importantes. Quando em normoxia, óxido nitroso a 80%, as alteraçöes renais foram menores, mostrando que muitas das alteraçöes provocadas pela associaçäo óxido-nitroso-oxigênio devem ser imputadas também ao próprio oxigênio (hiperoxia) e näo somente ao óxido nitroso