Cláudia Regina Fernandes

The Effects of Abdominal Opening on Respiratory Mechanics During General Anesthesia in Normal and Morbidly Obese Patients: A Comparative Study

Morbid obesity has a profound effect on respiratory mechanics and gas exchange. However, most studies were performed in morbidly obese patients before or after anesthesia. We tested the hypothesis that anesthesia and abdominal opening could modify the elastic and resistive properties of the respiratory system. Eleven morbidly obese and eight normal-weight patients scheduled for gastric binding and cancer treatment, respectively, under laparotomy were studied. Respiratory mechanics, partitioned into its lung and chest wall components, were investigated during surgery by means of the end-inspiratory inflation occlusion method and esophageal balloon at five time points. Static respiratory and lung compliance were markedly reduced in obese patients; on the contrary, static compliance of chest wall presented comparable values in both groups. Obese patients also presented higher resistances of the total respiratory system, lung and chest wall, as well as “additional” lung resistance. Mainly in obese patients, laparotomy provoked a significant increase in lung compliance and decrease in “additional” lung resistance 1 h after the peritoneum was opened, which returned to original values after the peritoneum had been closed (P < 0.005). In obese patients, low respiratory compliance and higher airway resistance were mainly determined by the lung component.

O sistema respiratório e o idoso: implicações anestésicas

BACKGROUND AND OBJECTIVES Respiratory complications are responsible for a major number of elderly deaths after surgical procedures. Aging entails an important decrease in respiratory system functional reserves, while an increasing number of elderly people are being submitted to increasingly complex procedures. This study is a review of the respiratory system during aging and of anesthesia-induced changes in the elderly, emphasizing preoperative evaluation of respiratory function, postoperative pulmonary complications and details of anesthetic management. CONTENTS Physiologic respiratory changes due to aging are presented, with emphasis in pulmonary volume and capacity abnormalities, respiratory mechanics and gas exchange provided by anesthesia. Perioperative pulmonary mortality and morbidity in elderly patients are addressed, emphasizing the importance of appropriate preoperative evaluation, from stress tests to specific tests, to quantify pulmonary functional reserves. Appropriate anesthetic techniques for the elderly are discussed. CONCLUSIONS Aging brings about several respiratory system changes. Evidences have shown that, even in the absence of pulmonary disease, advanced age is a risk factor for postoperative pulmonary complications. It is necessary a thorough evaluation of preoperative respiratory function, adequate anesthetic management and specific postoperative care.JUSTIFICATIVA E OBJETIVOS: As complicacoes respiratorias sao responsaveis por grande parte dos obitos apos procedimentos cirurgicos que ocorrem na populacao geriatrica. O envelhecimento causa importante diminuicao da reserva funcional do sistema respiratorio, e um numero crescente de pacientes idosos esta sendo submetido a procedimentos cada vez mais complexos. O objetivo deste trabalho e revisar o sistema respiratorio durante o processo de envelhecimento, as alteracoes causadas pela anestesia no idoso, enfatizando a avaliacao pre-operatoria da funcao respiratoria, complicacoes pulmonares pos-operatorias e detalhes do manuseio anestesico. CONTEUDO: Sao apresentadas as alteracoes respiratorias fisiologicas do envelhecimento. Sao enfatizadas as alteracoes de volume e capacidades pulmonares, da mecânica respiratoria e de trocas gasosas proporcionadas pela anestesia. Sao abordados aspectos relativos a morbimortalidade pulmonar pos-operatoria em geriatria, destacando-se a importância da adequada avaliacao pre-operatoria, considerando-se desde testes de esforco ate testes especificos que quantificam a reserva funcional pulmonar. Sao discutidas tecnicas anestesicas apropriadas em idosos. CONCLUSOES: O envelhecimento e acompanhado de alteracoes no sistema respiratorio. Evidencias demonstram que mesmo na ausencia de pneumopatia, a idade avancada constitui fator de risco para complicacoes pulmonares no pos-operatorio. Deve haver preocupacao com adequada avaliacao pre-operatoria da funcao respiratoria, apropriado manuseio anestesico e cuidados pos-operatorios especificos.

A importância da pressão pleural na avaliação da mecânica respiratória

JUSTIFICATIVA E OBJETIVOS: Para a particao das medidas de mecânica do sistema respiratorio em seus componentes pulmao e parede toracica, faz-se necessario o conhecimento da pressao pleural. A finalidade desta revisao foi discutir sobre medidas alternativas a obtencao da pressao pleural para o calculo da mecânica pulmonar, relatar as peculiaridades do metodo do balao esofagico para obtencao indireta da pressao pleural, as particularidades da obtencao da medida da pressao esofagica em pacientes sedados ou anestesiados, discorrer sobre a medida direta da pressao pleural e sua correlacao com a pressao esofagica, assim como relatar sobre o reflexo da PEEP nas pressoes pleural e esofagica. CONTEUDO: A variacao da pressao intra-esofagica reflete a variacao da pressao intrapleural, podendo ser usada como medida alternativa a pressao pleural direta, no estudo da mecânica dos componentes pulmao e parede do sistema respiratorio. A medida da pressao esofagica pode ser realizada por meio de um delicado balao posicionado no interior do esofago. O metodo e a tecnica foram observados e validados em seres humanos e animais em diferentes condicoes e posturas corporais. O emprego da PEEP em pacientes sob ventilacao controlada mecânica esta consolidado; no entanto, existem controversias da correlacao proxima entre a pressao esofagica e a pressao pleural em pacientes ventilados com PEEP, o que pode resultar em erros de calculo de mecânica respiratoria considerando a pressao esofagica. CONCLUSOES: O metodo do balao esofagico e o mais utilizado para a obtencao da medida indireta da pressao pleural. Em pacientes sedados ou anestesiados sem alteracoes significativas da complacencia respiratoria, a variacao da pressao esofagica corresponde a variacao da pressao pleural quando a PEEP e aplicada.BACKGROUND AND OBJECTIVES Pleural pressure has to be known for the partitioning of respiratory system mechanical measurements into their lung and chest wall components. This review aimed at discussing alternative methods to obtain pleural pressure to calculate pulmonary mechanics, at reporting peculiarities of the esophageal balloon method for obtaining indirect pleural pressure, peculiarities of esophageal pressure measurement in sedated or anesthetized patients, at discussing direct pleural pressure and its correlation with esophageal pressure, in addition to reporting on the impact of PEEP on pleural and esophageal pressures. CONTENTS Esophageal pressure variation reflects pleural pressure variation and may be used as alternative to direct pleural pressure in the study of lungs and chest wall mechanics. Esophageal pressure may be obtained with a delicate balloon placed inside the esophagus. Method and technique were observed and validated in humans and animals in different conditions and body positions. PEEP is a consolidated method for patients under mechanically controlled ventilation, however there are controversies about the close correlation between esophageal and pleural pressure in patients ventilated with PEEP, which may result in wrong respiratory mechanics calculation based on the esophageal pressure. CONCLUSIONS The esophageal balloon is the most common method to obtain indirect pleural pressure. In sedated or anesthetized patients without major respiratory compliance changes, esophageal pressure variation corresponds to pleural pressure variation when PEEP is applied.

[The respiratory system and the elderly: anesthetic implications.].

BACKGROUND AND OBJECTIVES Respiratory complications are responsible for a major number of elderly deaths after surgical procedures. Aging entails an important decrease in respiratory system functional reserves, while an increasing number of elderly people are being submitted to increasingly complex procedures. This study is a review of the respiratory system during aging and of anesthesia-induced changes in the elderly, emphasizing preoperative evaluation of respiratory function, postoperative pulmonary complications and details of anesthetic management. CONTENTS Physiologic respiratory changes due to aging are presented, with emphasis in pulmonary volume and capacity abnormalities, respiratory mechanics and gas exchange provided by anesthesia. Perioperative pulmonary mortality and morbidity in elderly patients are addressed, emphasizing the importance of appropriate preoperative evaluation, from stress tests to specific tests, to quantify pulmonary functional reserves. Appropriate anesthetic techniques for the elderly are discussed. CONCLUSIONS Aging brings about several respiratory system changes. Evidences have shown that, even in the absence of pulmonary disease, advanced age is a risk factor for postoperative pulmonary complications. It is necessary a thorough evaluation of preoperative respiratory function, adequate anesthetic management and specific postoperative care.JUSTIFICATIVA E OBJETIVOS: As complicacoes respiratorias sao responsaveis por grande parte dos obitos apos procedimentos cirurgicos que ocorrem na populacao geriatrica. O envelhecimento causa importante diminuicao da reserva funcional do sistema respiratorio, e um numero crescente de pacientes idosos esta sendo submetido a procedimentos cada vez mais complexos. O objetivo deste trabalho e revisar o sistema respiratorio durante o processo de envelhecimento, as alteracoes causadas pela anestesia no idoso, enfatizando a avaliacao pre-operatoria da funcao respiratoria, complicacoes pulmonares pos-operatorias e detalhes do manuseio anestesico. CONTEUDO: Sao apresentadas as alteracoes respiratorias fisiologicas do envelhecimento. Sao enfatizadas as alteracoes de volume e capacidades pulmonares, da mecânica respiratoria e de trocas gasosas proporcionadas pela anestesia. Sao abordados aspectos relativos a morbimortalidade pulmonar pos-operatoria em geriatria, destacando-se a importância da adequada avaliacao pre-operatoria, considerando-se desde testes de esforco ate testes especificos que quantificam a reserva funcional pulmonar. Sao discutidas tecnicas anestesicas apropriadas em idosos. CONCLUSOES: O envelhecimento e acompanhado de alteracoes no sistema respiratorio. Evidencias demonstram que mesmo na ausencia de pneumopatia, a idade avancada constitui fator de risco para complicacoes pulmonares no pos-operatorio. Deve haver preocupacao com adequada avaliacao pre-operatoria da funcao respiratoria, apropriado manuseio anestesico e cuidados pos-operatorios especificos.

Currículo baseado em competências na residência médica

Competency was defined as a synthesis of knowledge, skills and attitudes that, when integrated, provide the individual with the integrated use of cognitive and technical resources to diagnose, treat and provide more benefits and less morbidity to the patient and reduce cost to the institutions. This definition was subsequently broadened, adding that it is context-dependent, demands experience and the capacity to reflect and continue learning. The aim of this study is to describe the curriculum implemented in the Anesthesiology Residency Program of the Walter Cantidio University Hospital (HUWC) at the Federal University of Ceara, which was based on six main competencies: communication, documentation, pre-operative care, intra-operative care, post-operative care, quality management and perioperative safety. The assessment tools used for the curriculum are also presented: cognitive testing, Direct Observation of Procedural Skills (DOPS), logbook, Multiple Source Feedback (MSF) and resident evaluation of the preceptors. The implementation of the curriculum andassessment processes aimed to broaden the qualification of both the anesthesiology resident sand the preceptors who train thes especialists.

Recomendações da Sociedade Brasileira de Anestesiologia para segurança em anestesia regional

Foram realizadas buscas em múltiplas bases de dados (Medline de 1965 a 2011, Cochrane Library, e LILACS) e em referências cruzadas com o material levantado para identificação de artigos com melhor desenho metodológico. Após estas buscas, seguiu-se avaliação crítica de seu conteúdo e classificação de acordo com a força da evidência. As buscas foram realizadas entre dezembro de 2010 e abril de 2011. Para buscas no PubMed, foram utilizadas as seguintes estratégias de pesquisa:

Brazilian Society of Anesthesiology Recommendations for safety in regional anesthesia

1. MD, PhD, Anesthesiologist; Professor at the Medical School of Universidade de Fortaleza (UNIFOR); Responsible for the Centro de Ensino e Treinamento (CET/MEC/SBA) at Hospital Universitario Walter Cantidio, Universidade Federal do Ceara (UFC); President of the Perioperatative Medicine Committee of SBA 2. MD, PhD, Anesthesiologist; Professor at the Anesthesiology Department of Faculdade de Medicina da Universidade Federal de Uberlândia (FMUFU); Responsible for the CET/SBA at FMUFU 3. MD, Anesthesiologist at Instituto Nacional do Câncer (INCA); Co-responsible for the CET/SBA at Hospital Universitario Pedro Ernesto (HUPE), Universidade do Estado do Rio de Janeiro (UERJ); Instructor at the Curso Suporte Avancado de Vida em Anestesia – SAVA/SBA 4. MD, Anesthesiologist; Coordinator of the Anesthesiology Service at Instituto do Câncer de Sao Paulo (ICESP); Member of the SBA Malignant Hyperthermia Committee 5. MD, Anesthesiologist at Hospital Universitario Oswaldo Cruz, Universidade Estadual de Pernambuco (UPE); Co-responsible for the CET/SBA of Hospital da Restauracao, Hospital Getulio Vargas and Hospital Oswaldo Cruz, UPE; President of the Brazilian Society of Anesthesiology, 2011

Importance of pleural pressure for the evaluation of respiratory mechanics

JUSTIFICATIVA E OBJETIVOS: Para a particao das medidas de mecânica do sistema respiratorio em seus componentes pulmao e parede toracica, faz-se necessario o conhecimento da pressao pleural. A finalidade desta revisao foi discutir sobre medidas alternativas a obtencao da pressao pleural para o calculo da mecânica pulmonar, relatar as peculiaridades do metodo do balao esofagico para obtencao indireta da pressao pleural, as particularidades da obtencao da medida da pressao esofagica em pacientes sedados ou anestesiados, discorrer sobre a medida direta da pressao pleural e sua correlacao com a pressao esofagica, assim como relatar sobre o reflexo da PEEP nas pressoes pleural e esofagica. CONTEUDO: A variacao da pressao intra-esofagica reflete a variacao da pressao intrapleural, podendo ser usada como medida alternativa a pressao pleural direta, no estudo da mecânica dos componentes pulmao e parede do sistema respiratorio. A medida da pressao esofagica pode ser realizada por meio de um delicado balao posicionado no interior do esofago. O metodo e a tecnica foram observados e validados em seres humanos e animais em diferentes condicoes e posturas corporais. O emprego da PEEP em pacientes sob ventilacao controlada mecânica esta consolidado; no entanto, existem controversias da correlacao proxima entre a pressao esofagica e a pressao pleural em pacientes ventilados com PEEP, o que pode resultar em erros de calculo de mecânica respiratoria considerando a pressao esofagica. CONCLUSOES: O metodo do balao esofagico e o mais utilizado para a obtencao da medida indireta da pressao pleural. Em pacientes sedados ou anestesiados sem alteracoes significativas da complacencia respiratoria, a variacao da pressao esofagica corresponde a variacao da pressao pleural quando a PEEP e aplicada.BACKGROUND AND OBJECTIVES Pleural pressure has to be known for the partitioning of respiratory system mechanical measurements into their lung and chest wall components. This review aimed at discussing alternative methods to obtain pleural pressure to calculate pulmonary mechanics, at reporting peculiarities of the esophageal balloon method for obtaining indirect pleural pressure, peculiarities of esophageal pressure measurement in sedated or anesthetized patients, at discussing direct pleural pressure and its correlation with esophageal pressure, in addition to reporting on the impact of PEEP on pleural and esophageal pressures. CONTENTS Esophageal pressure variation reflects pleural pressure variation and may be used as alternative to direct pleural pressure in the study of lungs and chest wall mechanics. Esophageal pressure may be obtained with a delicate balloon placed inside the esophagus. Method and technique were observed and validated in humans and animals in different conditions and body positions. PEEP is a consolidated method for patients under mechanically controlled ventilation, however there are controversies about the close correlation between esophageal and pleural pressure in patients ventilated with PEEP, which may result in wrong respiratory mechanics calculation based on the esophageal pressure. CONCLUSIONS The esophageal balloon is the most common method to obtain indirect pleural pressure. In sedated or anesthetized patients without major respiratory compliance changes, esophageal pressure variation corresponds to pleural pressure variation when PEEP is applied.

Fatal Recrudescence of Malignant Hyperthermia in an Infant with Moebius Syndrome

BACKGROUND AND OBJECTIVES Malignant hyperthermia (MH) is a pharmacogenetic skeletal muscle disorder characterized by a hypermetabolic state after anesthesia with succinylcholine and/ or volatile anesthetics. Various neuromuscular syndromes are associated with susceptibility; however, Moebius syndrome has not been reported. Dantrolene is the drug of choice for treatment. Recurrence may occur in up to 20% of cases after the initial event treatment. CASE REPORT Male infant, fi rst twin, 7 months old, weighing 6.5kg and presenting with Moebius syndrome was admitted for clubfoot repair. The patient had MH after exposure to sevoflurane and succinylcholine, which was readily reversed with dantrolene maintained for 24 hours. Ten hours after dantrolene discontinuation, there was recrudescence of MH that did not respond satisfactorily to treatment, and the patient died. DISCUSSION Musculoskeletal disorders in children are associated with increased risk of developing MH, although Moebius syndrome has not yet been reported. Dantrolene is the drug of choice for treating this syndrome; prophylaxis is indicated during the fi rst 24-48 hours of the episode onset. The main risk factors for recurrence are muscular type, long latency after anesthetic exposure, and increased temperature. The child had only one risk factor. This case leads us to reflect on how we must be attentive to children with musculoskeletal disease and maintain treatment for 48 hours.

Malignant Hyperthermia in Liver Transplantation

MH produces rapid increase in body temperature (by as much as 1oC in five minutes) and extreme acidosis. These are a result of acute loss of control of intracellular calcium levels and compensatory uncontrolled increases in skeletal muscle metabolism, which may progress to severe rhabdomyolysis. Critical worldwide attention to MH began in 1960 with the reports of Denborough and Lovell. They described MH in a young man who had a history of several deaths of relatives during anesthesia. He developed tachycardia, hot and sweaty skin, peripheral mottling and cyanosis during general anesthesia using halothane. After prompt symptomatic treatment, the episode was aborted5-6. The term malignant hyperthermia was first quoted by Wilson and colleagues in 19677. In this same year, Dantrolene Sodium, a hydantoin derivative (1-[5-(4-nitrophenyl)-2-furanyl]methylene]imino]-2,4imidazolidinedione), was first used because of its possible muscle-relaxing properties8. Shortly thereafter, dantrolene was shown to alleviate muscle spasticity effectively in animals9 and humans10. Later, it was shown that dantrolene uncoupled the excitationcontraction process during skeletal muscle stimulation11. A few years later, an association between MH and porcine stress syndrome was proposed, providing an animal model for MH12-13. Because malignant hyperthermia was thought to result from continuous muscle contraction, perhaps through an abnormality in the excitation-contraction coupling mechanism, the compound was tested as a treatment for this condition14.