Comparison of C-reactive protein and serum amyloid a protein in septic shock patients.

Septic shock is a severe inflammatory state caused by an infectious agent. Our purpose was to investigate serum amyloid A (SAA) protein and C-reactive protein (CRP) as inflammatory markers of septic shock patients. Here we evaluate 29 patients in postoperative period, with septic shock, in a prospective study developed in a surgical intensive care unit. All eligible patients were monitored over a 7-day period by sequential organ failure assessment (SOFA) score, daily CRP, SAA, and lactate measurements. CRP and SAA strongly correlated up to the fifth day of observation but were not good predictors of mortality in septic shock.

Incidence and prophylaxis of nausea and vomiting in post-anesthetic recovery in a tertiary teaching hospital.

BACKGROUND AND OBJECTIVES: Postoperative nausea and vomiting (PONV) is frequent and potentially a severe complication that increases the length of anesthetic recovery and causes patient dissatisfaction. The evaluation of the risk of PONV and institution of prophylactic measures aiming the well-being of patients and cost reduction are frequent in the medical literature. This observational study evaluated the incidence, risk factors, and adjustment and effectivity of the prophylaxis of PONV in the recovery room of a tertiary teaching school. METHODS: Information obtained from patients' records and questionnaires answered by patients included age, major predictive factors for PONV (female gender, history, absence of smoking, and postoperative use of opioids), prophylactic drugs administered, development of PONV type of surgery and anesthesia, use of nitrous oxide, clinical status, and length of stay in the recovery room. RESULTS: An incidence of 18.5% of nausea and 8.5% of vomiting in the immediate postoperative period was observed. A correlation between major risk factors and the development of PONV was also observed. A correlation between those factors and prophylactic anti-emetic drugs, as well as between their use and the development of PONV, was not observed. However, a tendency to administer prophylactic medication to young female patients was observed. CONCLUSIONS: The concerns of the anesthesiologists of the institution with PONV were evident. However, the absence of correlation between risk and prophylaxis suggests an empirical and ineffective procedure. Factors that were not evaluated were suggested by the absence between PONV and the use of antiemetic drugs. The orientation for anesthesiologists regarding more effective prophylactic measures can improve care of the population assisted.

[Surgery is unlikely to be enough for a patient to stop smoking 24h prior to hospital admission]. / É improvável que a cirurgia seja suficiente para que o paciente pare de fumar 24 horas antes da internação hospitalar.

INTRODUCTION: The need for surgery can be a decisive factor for long-term smoking cessation. On the other hand, situations that precipitate stress could precipitate smoking relapse. The authors decided to study the impact of a surgery on the patient's effort to cease smoking for, at least, 24h before hospital admission and possible relapse on the last 24h before hospital admission for ex-smokers. METHODS: Smoker, ex-smokers and non-smokers adults, either from pre-anesthetic clinic or recently hospital admitted for scheduled elective surgeries that were, at most, 6h inside the hospital buildings were included in the study. The patients answered a questionnaire at the ward or at the entrance of the operating room (Admitted group) or at the beginning of the first pre-anesthetic consultation (Clinic group) and performed CO measurements. RESULTS: 241 patients were included, being 52 ex-smokers and 109 never smokers and 80 non-smokers. Smokers had higher levels of expired carbon monoxide than non-smokers and ex-smokers (9.97±6.50 vs. 2.26±1.65 vs. 2.98±2.69; p=0.02). Among the smokers, the Clinic group had CO levels not statistically different of those on the Admitted group (10.93±7.5 vs. 8.65±4.56; p=0.21). The ex-smokers presented with no significant differences for the carbon monoxide levels between the Clinic and Admitted groups (2.9±2.3 vs. 2.82±2.15; p=0.45). CONCLUSION: A medical condition, such as a surgery, without proper assistance is unlikely to be enough for a patient to stop smoking for, at least, 24h prior to admission. The proximity of a surgery was not associated with smoking relapse 24h before the procedure.

Early dexamethasone treatment for septic shock patients: a prospective randomized clinical trial.

CONTEXT AND OBJECTIVE: Sepsis and septic shock are very common conditions among critically ill patients that lead to multiple organ dysfunction syndrome (MODS) and death. Our purpose was to investigate the efficacy of early administration of dexamethasone for patients with septic shock, with the aim of halting the progression towards MODS and death. DESIGN AND SETTING: Prospective, randomized, double-blind, single-center study, developed in a surgical intensive care unit at Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo. METHODS: The study involved 29 patients with septic shock. All eligible patients were prospectively randomized to receive either a dose of 0.2 mg/kg of dexamethasone (group D) or placebo (group P), given three times at intervals of 36 hours. The patients were monitored over a seven-day period by means of the sequential organ failure assessment score. RESULTS: Patients treated with dexamethasone did not require vasopressor therapy for as much time over the seven-day period as did the placebo group (p = 0.043). Seven-day mortality was 67% in group P (10 out of 15) and 21% in group D (3 out of 14) (relative risk = 0.31, 95% confidence interval 0.11 to 0.88). Dexamethasone enhanced the effects of vasopressor drugs. CONCLUSIONS: Early treatment with dexamethasone reduced the seven-day mortality among septic shock patients and showed a trend towards reduction of 28-day mortality.

Thoracic sympathetic block reduces respiratory system compliance.

CONTEXT AND OBJECTIVE: Thoracic epidural anesthesia (TEA) following thoracic surgery presents known analgesic and respiratory benefits. However, intraoperative thoracic sympathetic block may trigger airway hyperreactivity. This study weighed up these beneficial and undesirable effects on intraoperative respiratory mechanics. DESIGN AND SETTING: Randomized, double-blind clinical study at a tertiary public hospital. METHODS: Nineteen patients scheduled for partial lung resection were distributed using a random number table into groups receiving active TEA (15 ml 0.5% bupivacaine, n = 9) or placebo (15 ml 0.9% saline, n = 10) solutions that also contained 1:200,000 epinephrine and 2 mg morphine. Under general anesthesia, flows and airway and esophageal pressures were recorded. Pressure-volume curves, lower inflection points (LIP), resistance and compliance at 10 ml/kg tidal volume were established for respiratory system, chest wall and lungs. Students t test was performed, including confidence intervals (CI). RESULTS: Bupivacaine rose 5 +/- 1 dermatomes upwards and 6 +/- 1 downwards. LIP was higher in the bupivacaine group (6.2 +/- 2.3 versus 3.6 +/- 0.6 cmH2O, p = 0.016, CI = -3.4 to -1.8). Respiratory system and lung compliance were higher in the placebo group (respectively 73.3 +/- 10.6 versus 51.9 +/- 15.5, p = 0.003, CI = 19.1 to 23.7; 127.2 +/- 31.7 versus 70.2 +/- 23.1 ml/cmH2O, p < 0.001, CI = 61 to 53). Resistance and chest wall compliance showed no difference. CONCLUSION: TEA decreased respiratory system compliance by reducing its lung component. Resistance was unaffected. Under TEA, positive end-expiratory pressure and recruitment maneuvers are advisable.

Effects of single dose of dexamethasone on patients with systemic inflammatory response.

CONTEXT AND OBJECTIVE: Systemic inflammatory response syndrome (SIRS) is a very common condition among critically ill patients. SIRS, sepsis, septic shock and multiple organ dysfunction syndrome (MODS) can lead to death. Our aim was to investigate the efficacy of a single dose of dexamethasone for blocking the progression of systemic inflammatory response syndrome. DESIGN AND SETTING: Prospective, randomized, double-blind, single-center study in a postoperative intensive care unit (Surgical Support Unit) at Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo. METHODS: The study involved 29 patients with SIRS. All eligible patients were prospectively randomized to receive either a single dose of 0.2 mg/kg of dexamethasone or placebo, after SIRS was diagnosed. The patients were monitored over a seven-day period using Sequential Organ Failure Assessment score (SOFA). RESULTS: The respiratory system showed an improvement on the first day after dexamethasone was administered, demonstrated by the improved PaO2/FiO2 ratio (p < 0.05). The cardiovascular system of patients requiring vasopressor therapy also improved over the first two days, with a better evolution in the dexamethasone group (p < 0.05). Non-surviving patients presented higher lactate assays than did survivors (p < 0.05) during this period. CONCLUSIONS: Dexamethasone enhanced the effects of vasopressor drugs and evaluation of the respiratory system showed improvements (better PaO2/FiO2 ratio), one day after its administration. Despite these improvements, the single dose of dexamethasone did not block the evolution of SIRS.

Elevation of a patient's trunk and legs does not influence length of stay in the post-anesthesia care unit.

CONTEXT: Patient recovery time after anesthesia depends on problem-oriented monitoring and individual assessment. OBJECTIVE: To investigate the influence of patient positioning on post-anesthesia recovery time. TYPE OF STUDY: Retrospective. SETTING: Post-anesthesia care unit, Hospital das Clínicas, São Paulo. METHODS: Data were obtained from patients recovering from anesthesia in a supine horizontal position or with their trunk and legs elevated at 30 degrees. Data were recorded every 30 minutes. The start time was considered to be the admission to the unit, and the final measurement was taken with the patient reached an Aldrete-Kroulik index of 10. The length of time until discharge was recorded. RESULTS: 442 patients recovering after general (n = 274) or regional anesthesia (n = 168) were assigned to be kept in a supine position or with their trunk and legs elevated. There was no difference in the medians for non-parametric results, between supine position (75 min, n = 229) and trunk and legs elevated (70 min, n = 213); p = 0.729. Patients recovered faster from regional anesthesia with trunk and legs elevated (70 min) than in the supine position (84.5 min), although not significantly (p = 0.097). There was no difference between patients recovering from general anesthesia, no matter the positioning (70 min; p = 0.493). DISCUSSION: Elevated legs may supposedly improve venous return and cardiac output since spinal anesthesia blocks sympathetic system and considering leg-raising has been shown to improve cardiac output from hipovolemia. Our findings did not support this hypothesis. Some limitations included a retrospective collection of data that did not allow randomization for recovery position and the unregistered duration of the exposure to the anesthetic drugs. CONCLUSIONS: There was no difference in anesthesia recovery time in relation to positioning patients supinely or with trunk and legs elevated.

Surgery is unlikely to be enough for a patient to stop smoking 24 h prior to hospital admission / É improvável que a cirurgia seja suficiente para que o paciente pare de fumar 24 horas antes da internação hospitalar

Abstract Introduction The need for surgery can be a decisive factor for long-term smoking cessation. On the other hand, situations that precipitate stress could precipitate smoking relapse. The authors decided to study the impact of a surgery on the patient's effort to cease smoking for, at least, 24 h before hospital admission and possible relapse on the last 24 h before hospital admission for ex-smokers. Methods Smoker, ex-smokers and non-smokers adults, either from pre-anesthetic clinic or recently hospital admitted for scheduled elective surgeries that were, at most, 6 h inside the hospital buildings were included in the study. The patients answered a questionnaire at the ward or at the entrance of the operating room (Admitted group) or at the beginning of the first pre-anesthetic consultation (Clinic group) and performed CO measurements. Results 241 patients were included, being 52 ex-smokers and 109 never smokers and 80 non-smokers. Smokers had higher levels of expired carbon monoxide than non-smokers and ex-smokers (9.97 ± 6.50 vs. 2.26 ± 1.65 vs. 2.98 ± 2.69; p = 0.02). Among the smokers, the Clinic group had CO levels not statistically different of those on the Admitted group (10.93 ± 7.5 vs. 8.65 ± 4.56; p = 0.21). The ex-smokers presented with no significant differences for the carbon monoxide levels between the Clinic and Admitted groups (2.9 ± 2.3 vs. 2.82 ± 2.15; p = 0.45). Conclusion A medical condition, such as a surgery, without proper assistance is unlikely to be enough for a patient to stop smoking for, at least, 24 h prior to admission. The proximity of a surgery was not associated with smoking relapse 24 h before the procedure.

Resumo Introdução A necessidade de cirurgia pode ser um fator decisivo para a cessação do tabagismo em longo prazo. Por outro lado, situações que precipitam o estresse podem precipitar a recaída do tabagismo. Decidimos avaliar o impacto de uma cirurgia no esforço do paciente para deixar de fumar durante pelo menos 24 horas antes da internação hospitalar e a possível recaída nas últimas 24 horas anteriores à internação em ex-fumantes. Métodos Fumantes, ex-fumantes e não fumantes adultos, quer de clínica pré-anestésica ou recentemente internados para cirurgias eletivas programadas que ficariam, no máximo, seis horas dentro das unidades hospitalares, foram incluídos no estudo. Os pacientes responderam um questionário na enfermaria ou na entrada da sala de operação (Grupo Internação) ou no início da primeira consulta pré-anestesia (Grupo Clínico) e fizeram mensurações dos níveis de CO. Resultados No total, 241 pacientes foram incluídos: 52 ex-fumantes, 109 que nunca fumaram e 80 não fumantes. Os fumantes apresentaram níveis mais elevados de monóxido de carbono expirado que os não fumantes e ex-fumantes (9,97 ± 6,50 vs. 2,26 ± 1,65 vs. 2,98 ± 2,69;p = 0,02). Entre os fumantes, o Grupo Clínico apresentou níveis de CO não estatisticamente diferentes daqueles do Grupo Internação (10,93 ± 7,5 vs. 8,65 ± 4,56; p = 0,21). Os ex-fumantes não apresentaram diferenças significativas entre os grupos Clínico e Internação para os níveis de monóxido de carbono (2,9 ± 2,3 vs. 2,82 ± 2,15; p = 0,45). Conclusão É improvável que uma condição médica, como uma cirurgia, sem assistência adequada seja suficiente para que um paciente pare de fumar, pelo menos, 24 horas antes da internação. A proximidade de uma cirurgia não foi associada à recaída do tabagismo nas 24 horas anteriores ao procedimento.

El efecto del flumazenil sobre la recuperación de anestesia general con isoflurano: una prueba aleatoria controlada / Effect of flumazenil on recovery from general anesthesia with isoflurane: A randomized controlled trial

Background and objectives: The inhalational anesthetic isoflurane is widely used in general anesthetics. Its mechanism of action involves interaction with the receptor of gamma-aminobutyric acid (GABA), which is also the binding site for benzodiazepines. Flumazenil, benzodiazepine antagonist, reverses the effects of these drugs in GABA receptors and could therefore also reverse the effect of isoflurane. In anesthesia practice, extubation and early anesthetic recovery reduce morbidity and incidence of complications. The objective of this trial is to determine whether the use of lumazenil may contribute to faster recovery from anesthesia. Methods: Forty patients scheduled to undergo general anesthesia with isolurane were enrolled in this prospective, double-blind, randomized trial. Patients were randomized to receive, at the end of anesthesia, lumazenil or placebo as allocated into two groups. The anesthetic technique was standardized. The groups were compared concerning values of cerebral state index (CSI), heart rate, blood pressure and oxygen saturation from the application of flumazenil or placebo until 30 min after injection. Data regarding time to extubation, time to reach 10 points in the Aldrete-Kroulic score (AK = 10) and Vigilance score (VS = 10) was also collected. ANOVA test was applied to analyze the results, considering p < 0.05. Results:Patients receiving flumazenil achieved faster extubation than the control (p = 0.033). No differences were observed in values of CSI, the time until AK = 10 and until VS = 10. Conclusions: Administration of lumazenil at the end of isolurane general anesthesia resulted in earlier extubation in studied patients.

Introducción y objetivos: El isoflurano es un anestésico inhalatorio ampliamente utilizado en anestesia general. Su mecanismo de acción involucra el receptor del ácido gamma-aminobutírico. Dicho receptor es también el sitio de acción de las benzodiazepinas. El flumazenil, antagonista benzodiazepínico, podría revertir los efectos del isoflurano. En la práctica, la extubación y recuperación anestésica tempranas reducen la morbilidad e incidencia de complicaciones. El objetivo del estudio es determinar la contribución del uso del flumazenil en la recuperación anestésica. Métodos: Se realizó un estudio doble ciego, prospectivo, aleatorio de 40 pacientes bajo anestesia general con isoflurano que recibieron flumazenil o placebo según aleatorización previa. La técnica anestésica fue estandarizada. Los parámetros comparados en los 2 grupos fueron frecuencia cardiaca, tensión arterial, saturación de oxígeno y niveles del Índice Biespectral, desde la aplicación del flumazenil y durante los 30 minutos posteriores. El tiempo transcurrido entre la inyección del medicamento y la extubación, así como el tiempo requerido para alcanzar 10 puntos en la Escala de Aldrete-Kroulic y la Escala de Vigilancia, también fueron contabilizados. El análisis de la varianza fue aplicado para comparar los datos, considerando p<0.05. Resultados: Los pacientes que recibieron flumazenil fueron extubados en menor tiempo que los del grupo placebo (P = 0.033). No se observaron diferencias entre los valores del Índice Biespectral y el tiempo necesario para alcanzar 10 puntos en la Escala de Aldrete-Kroulic y la Escala de Vigilancia. Conclusiones: La administración de flumazenil al final de la anestesia general con isoflurano disminuyó el tiempo a la extubación.

A sigmoidal fit for pressure-volume curves of idiopathic pulmonary fibrosis patients on mechanical ventilation: clinical implications.

OBJECTIVE: Respiratory pressure-volume curves fitted to exponential equations have been used to assess disease severity and prognosis in spontaneously breathing patients with idiopathic pulmonary fibrosis. Sigmoidal equations have been used to fit pressure-volume curves for mechanically ventilated patients but not for idiopathic pulmonary fibrosis patients. We compared a sigmoidal model and an exponential model to fit pressure-volume curves from mechanically ventilated patients with idiopathic pulmonary fibrosis. METHODS: Six idiopathic pulmonary fibrosis patients and five controls underwent inflation pressure-volume curves using the constant-flow technique during general anesthesia prior to open lung biopsy or thymectomy. We identified the lower and upper inflection points and fit the curves with an exponential equation, V = A-B.e-k.P, and a sigmoid equation, V = a+b/(1+e-(P-c)/d). RESULTS: The mean lower inflection point for idiopathic pulmonary fibrosis patients was significantly higher (10.5 ± 5.7 cm H2O) than that of controls (3.6 ± 2.4 cm H2O). The sigmoidal equation fit the pressure-volume curves of the fibrotic and control patients well, but the exponential equation fit the data well only when points below 50% of the inspiratory capacity were excluded. CONCLUSION: The elevated lower inflection point and the sigmoidal shape of the pressure-volume curves suggest that respiratory system compliance is decreased close to end-expiratory lung volume in idiopathic pulmonary fibrosis patients under general anesthesia and mechanical ventilation. The sigmoidal fit was superior to the exponential fit for inflation pressure-volume curves of anesthetized patients with idiopathic pulmonary fibrosis and could be useful for guiding mechanical ventilation during general anesthesia in this condition.

C-reactive protein is not a useful indicator for infection in surgical intensive care units.

CONTEXT AND OBJECTIVE: C-reactive protein (CRP) is commonly used as a marker for inflammatory states and for early identification of infection. This study aimed to investigate CRP as a marker for infection in patients with postoperative septic shock. DESIGN AND SETTING: Prospective, single-center study, developed in a surgical intensive care unit at Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo. METHODS: This study evaluated 54 patients in the postoperative period, of whom 29 had septic shock (SS group) and 25 had systemic inflammatory response syndrome (SIRS group). All of the patients were monitored over a seven-day period using the Sequential Organ Failure Assessment (SOFA) score and daily CRP and lactate measurements. RESULTS: The daily CRP measurements did not differ between the groups. There was no correlation between CRP and lactate levels and the SOFA score in the groups. We observed that the plasma CRP concentrations were high in almost all of the patients. The patients presented an inflammatory state postoperatively in response to surgical aggression. This could explain the elevated CRP measurements, regardless of whether the patient was infected or not. CONCLUSIONS: This study did not show any correlation between CRP and infection among patients with SIRS and septic shock during the early postoperative period.

Incidencia de complicaciones neurológicas y cefalea pospunción dural luego de anestesia regional en la práctica obstétrica: un estudio retrospectivo de 2399 pacientes / Incidence of neurological complications and post-dural puncture headache after regional anesthesia in obstetric practice: A retrospective study of 2399 patients

Introducción y objetivos: La anestesia regional brinda una excelente anestesia y analgesia en pacientes obstétricas, pero existe el potencial de complicaciones tales como la cefalea pospunción dural y lesión neurológica permanente o transitoria. El presente estudio pretende describir la incidencia de la cefalea pospunción dural y daño neurológico en la población obstétrica de un hospital universitario que fue tratada con bloqueo neuroaxial, en comparación con la literatura mundial e identificar los factores de riesgo. Material y métodos: Se hizo una cohorte retrospectiva incluyendo los datos recolectados a partir de los registros de consultas posanestesia durante el año 2010. El análisis central se hizo en función de las quejas de déficit neurológico periférico y cefaleas reportadas por los pacientes, el tipo de anestesia y el procedimiento quirúrgico realizado. Se aplicó un análisis de regresión múltiple para investigar la relación entre el inicio de parestesias de las extremidades inferiores y el tiempo en que permanecieron estas pacientes en posición ginecológica y otras variables. Resultados: Se evaluaron en total 2399 pacientes embarazadas tratadas con bloqueo neuroaxial. Las complicaciones neurológicas que se presentaron en estas pacientes se dividieron en parestesias de las extremidades inferiores (0,3%), irritación radicular transitoria (0,1%) y cefalea pospunción dural (3%). Las pacientes que permanecieron más de 60 min en posición ginecológica mostraron un índice de probabilidades (odds ratio) de evolución con parestesia de las extremidades inferiores de 1,75, y las pacientes que estuvieron más de 120 min mostraron un índice de probabilidades de 2,1, pero sin significación estadística. Conclusiones: Las pacientes que se sometieron a bloqueo neuroaxial y se colocaron en posición ginecológica tenían mayores probabilidades de evolucionar con parestesias de las extremidades inferiores por el tiempo que permanecieron en esta posición.

Introduction and objectives: Regional anesthesia provides excellent anesthesia and analgesia in obstetric patients, but has potential for complications such as post-dural puncture headache and permanent or transient nerve damage. This study aimed to describe the incidence of post-dural puncture headache and nerve damage in the obstetric population of auniversity hospital that was submitted to neuraxial blockades, comparing with the world literature, and identify risk factors. Materials and methods: A retrospective cohort was performed including data collected in the records of post-anesthetic consults conducted during the year 2010. The main analysis was performed on the complaints of peripheral neurological deficits and headaches reported by patients, type of anesthesia and performed surgical procedures. A multiple regression analysis was performed to investigate the association between the onset of lower limb paresthesias and the length of stay of these patients in the gynecological position and other variables. Results: A total of 2399 pregnant patients who had undergone neuraxial blockade were eva-luated. Neurologic complications that occurred in these patients were divided into lower limb paresthesias (0.3%), transient radicular irritation (0.1%), and post-dural puncture headache (3%). The patients who stayed more than 60 min in gynecological position showed an odds ratio of evolution with lower limb paresthesias of 1.75 and patients who stayed more than 120 min showed an odds ratio of 2.1, but without statistical significance. Conclusions: Patients submitted to neuraxial blockades and placed in gynecological position were more likely to evolve with lower limb paresthesias related to duration of this position.

[Lactate as a predictor of mortality and multiple organ failure in patients with the systemic inflammatory response syndrome.]. / Lactato como prognóstico de mortalidade e falência orgânica em pacientes com síndrome da resposta inflamatória sistêmica.

BACKGROUND AND OBJECTIVES: The systemic inflammatory response syndrome (SIRS) is common in the postoperative period of critically ill patients. The objective of this study was to investigate the correlation between lactate level, multiple organ dysfunction, and mortality in patients with SIRS. METHODS: This prospective study evaluated 24 patients with a postoperative diagnosis of SIRS (American College of Chest Physicians/Society of Critical Care Medicine) in the surgical ICU. Lactate levels were determined in the first 24 hours after the diagnosis of SIRS and daily, for 7 days. Patients were divided in 2 groups: LE Group (lactate > 2 mmol.L-1) and LN Group (lactate < 2 mmol.L-1). Multiple organ failure was evaluated by the SOFA (Sequential Organ Failure Assessment) score daily, for 7 days. After the 7-day follow-up period patients were followed for up to 28 days, until discharge from the hospital or death. RESULTS: Thirteen patients were included in the LE Group after the diagnosis of SIRS and 11 patients in the LN Group. The relative risk (RR) of death in 7 days for the LE Group was 4.23 (CI 95% 2.25-7.95) times greater than in the LN Group in the first day of the study. The RR of death in 28 days was 1.7 times greater for the LE Group (CI 95% 0.84-3.46). The SOFA score was similar in both groups. CONCLUSIONS: Patients with elevated lactate in the first 24 hours after the diagnosis of SIRS did not have more organic dysfunction than patients with normal lactate levels, but they had an increased risk of death in 7 days.

A sigmoidal fit for pressure-volume curves of idiopathic pulmonary fibrosis patients on mechanical ventilation: clinical implications

OBJECTIVE: Respiratory pressure-volume curves fitted to exponential equations have been used to assess disease severity and prognosis in spontaneously breathing patients with idiopathic pulmonary fibrosis. Sigmoidal equations have been used to fit pressure-volume curves for mechanically ventilated patients but not for idiopathic pulmonary fibrosis patients. We compared a sigmoidal model and an exponential model to fit pressure-volume curves from mechanically ventilated patients with idiopathic pulmonary fibrosis. METHODS: Six idiopathic pulmonary fibrosis patients and five controls underwent inflation pressure-volume curves using the constant-flow technique during general anesthesia prior to open lung biopsy or thymectomy. We identified the lower and upper inflection points and fit the curves with an exponential equation, V = A-B.e-k.P, and a sigmoid equation, V = a+b/(1+e-(P-c)/d). RESULTS: The mean lower inflection point for idiopathic pulmonary fibrosis patients was significantly higher (10.5 ± 5.7 cm H2O) than that of controls (3.6 ± 2.4 cm H2O). The sigmoidal equation fit the pressure-volume curves of the fibrotic and control patients well, but the exponential equation fit the data well only when points below 50 percent of the inspiratory capacity were excluded. CONCLUSION: The elevated lower inflection point and the sigmoidal shape of the pressure-volume curves suggest that respiratory system compliance is decreased close to end-expiratory lung volume in idiopathic pulmonary fibrosis patients under general anesthesia and mechanical ventilation. The sigmoidal fit was superior to the exponential fit for inflation pressure-volume curves of anesthetized patients with idiopathic pulmonary fibrosis and could be useful for guiding mechanical ventilation during general anesthesia in this condition.

[Importance of critical events training for anesthesiology residents: experience with computer simulator.]. / Importância do treinamento de residentes em eventos adversos durante anestesia: experiência com o uso do simulador computadorizado.

BACKGROUND AND OBJECTIVES: Because of monitoring and drugs evolution, there has been a decrease in the incidence of critical events during anesthetic procedures. Despite this low frequency, critical event training for Anesthesiology residents remains important. This study aimed at evaluating Anesthesiology residents' critical care skills during computer-simulated anesthesia. METHODS: Seventeen anesthesiology residents (first and second year) and 5 anesthesiology instructors were evaluated. Using the Anesthesia Simulator Consultant (2.0 - 1995/Anesoft) simulations of ventricular fibrillation (VF) and anaphylactic reaction (AR) were performed. After simulation, results of each participant were printed and approaches to solve predetermined critical events were evaluated and scored. Participants have evaluated the simulator by filling out a questionnaire. RESULTS: There were no significant differences in means obtained by groups, but there has been a trend toward better performance of second year residents and Anesthesiology instructors during VF simulation. There has been a trend toward better performance of Anesthesiology instructors during AR simulation. CONCLUSIONS: Critical events management training should be the focus during residents and anesthesiologists training. Computer simulation could be a way to carry out such training.

Sedation and analgesia in intensive care.

BACKGROUND AND OBJECTIVES: Pain and anxiety may cause major discomfort, increase the risk for postoperative complications in surgical patients and may even prolong their hospital stay. This study aimed at reviewing concepts of sedation and analgesia in intensive care, updating knowledge and reviewing information available in the literature as well as already published consensus. CONTENTS: Sedation and analgesia are presented in separate, reviewing each group of available drugs, their major characteristics and side-effects. We have included some protocols used in our ICU for analgesia and sedation as well as the conclusions of the latest consensus of the American College of Critical Care Medicine and the Society of Critical Care Medicine. CONCLUSIONS: In spite of the therapeutic armamentarium available, there is a lack of understanding about major characteristics of drugs used for sedation and analgesia in Intensive Care. Developed consensus try to explain qualities and side-effects of most popular drugs, normalizing their use for ICU analgesia and sedation to benefit and faster recover patients.

[P ET CO2 and SpO2 allow adequate ventilatory adjustment in morbidly obese patients.]. / P ET CO2 e SpO2 permitem ajuste ventilatório adequado em pacientes obesos mórbidos.

BACKGROUND AND OBJECTIVES: Ventilation strategies for anesthesia in morbidly obese patients have been investigated, but an agreement has not been achieved yet. This study aimed at clinically evaluating ventilation adjustments based on oximetry and capnography readings in these patients during anesthesia. METHODS: Consent was obtained from the Institutional Ethics Committee and from patients. Smokers and respiratory or cardiac disease patients were excluded. Eleven patients with Body Mass Index (BMI) of 59.2 +/- 8.3 undergoing gastroplasty under general anesthesia were studied (Group O), with a control group (NO) composed of 8 non-obese patients (BMI 20.2 +/- 3.9) submitted to gastrectomy. Ventilator was adjusted to keep P ET CO2 below 40 mmHg and SpO2 above 95%. PEEP was not used. Through a CO2SMO Plus respiratory monitor, airway, alveolar and physiologic dead spaces (respectively VD aw, VD phy and VD alv), as well as alveolar tidal volume (TV alv) were measured. Arterial and central venous blood samples were used to calculate PaO2/FIO2 and VD phy/TV relationships. Data were compared and evaluated by ANOVA (p < 0.05). RESULTS: Tidal volume was 4.2 +/- 0.4 mL.kg-1 in Group O and 7.9 +/- 2.3 mL.kg-1 in Group NO for measured weight, and 11.5 +/- 1.8 mL.kg-1 in Group O and 6.6 +/- 1.1 mL.kg-1 in Group NO for ideal weight. PaO2 was lower and TV alv was higher in Group O (p < 0.008 and 0.0001, respectively). No difference was found in PaCO2, VD phy, VD alv and VD aw. CONCLUSIONS: SpO2 and P ET CO2 seem to assure adequate ventilation, which can be achieved in morbidly obese patients with tidal volumes adjusted to ideal weight.

[Airflow resistance of double-lumen tracheal tubes.]. / Resistência ao fluxo de gases através das cânulas de intubação de dupla luz.

UNLABELLED: BACKGROUNG AND OBJECTIVES: Double lumen tubes may determine different flow resistances. This disparity may result in non-homogeneous ventilation. This study aimed at comparing the resistive pressure of 37 FR double lumen tubes to distinct flows as compared to conventional adult tracheal tubes. METHODS: Tracheal tubes with internal diameters of 7; 7.5; 8 and 8.5 millimeters (mm) and 37 FR double lumen tubes were tested. Flows were generated and maintained by a conventional anesthesia ventilator. Resistive pressure generated in the tubes was measured by a variable inlet pneumotachograph and converted to a digital system. Resistances were obtained by dividing measured pressures by flows. Data were submitted to analysis of variance (ANOVA) and Tukeys test. RESULTS: Five independent measurements were obtained. All tubes were opened to the environment. Resistances are shown in cmH2O.L-1.s-1. Resistance is linearly increased with increased flow. The 37 FR tube had a resistive pattern similar to the 7.5 mm tracheal tube. The occlusion of any double lumen branch significantly increases flow resistance. Flows set at 0.1 L.s-1 to 0.2 L.s-1 resulted in similar resistive pressures for all tubes, except for the 7 mm or the occluded 37 FR tube (p < 0.001). CONCLUSIONS: Resistive patterns of 37 FR and 7,5 mm tubes were very similar. Any double lumen branch occlusion significantly increases resistance, however in a similar way for both branches for flows below 0.5 L.s-1. These results suggest the use of low inspiratory flow to minimize ventilatory system resistive pressure when any branch of a double-lumen tube is occluded.

Guidelines for inspiratory flow setting when measuring the pressure-volume relationship.

UNLABELLED: Acquisition of pressure-volume (PV) curves to improve ventilation strategy is time consuming when using static methods. Low-flow techniques use less time, but compliance values can be decreased by the resistance to flow in airways and tracheal tube (P-t). In this study, we determined the impact of three flows on the resistive component of airway pressure during anesthesia. We studied 10 ASA status P1/P2 patients with normal respiratory function. Airway and esophageal pressures were measured while volume-control ventilated with 6, 12, and 30 L/min continuous flows. PV curves, lower inflection point, respiratory system, and chest wall compliances at 250, 500, 750, and 1000 mL tidal volume were established before and after removing P-t. Data were submitted to analysis of variance. The inflection point was lower for the lower flow when comparing 6 and 12 with 30 L/min (P < 0.001). No difference was found between 6 and 12 L/min. Removal of P-t showed a difference only for 30 L/min (P = 0.004). Higher flows generated lower compliances. P-t subtraction reduced compliances only for 30 L/min. Chest wall compliances showed no difference between flows. We concluded that flows < or =12 L/min minimize P-t during intraoperative PV curves acquisition. Compliances suggest 6 L/min as the most adequate flow. IMPLICATIONS: We suggest guidelines for inspiratory flow setting when measuring the pressure-volume relationship during anesthesia based on the comparison among three different continuous flow values, aiming at better intraoperative respiratory settings in patients with normal respiratory function.

[Airflow resistance of shortened tracheal tubes.]. / Resistência ao fluxo de gases em cânulas de intubação traqueal com comprimento padrão diminuído.

BACKGROUND AND OBJECTIVES: Tracheal tube length may be shortened just after the cuff probably without noxious influence on airflow resistance. This study aimed at determining the effects of such shortening under different inspiratory flows. METHODS: Flow resistance was measured in tubes with internal diameters of 7; 7.5; 8; 8.5; 9 and 9.5 millimeters. Measurements were undertaken on standard tubes and on those shortened just after the cuff level. Flows were 0.07 liters per second (L.s-1), 0.1; 0.2; 0.33; 0.5 and 1 L.s-1. RESULTS: Resistances were progressively lower for larger internal diameters, but were higher for a same diameter under higher flow, both, in standard and shortened tubes. Shortened tubes showed lower or equal flow resistance as compared to standard tubes with the same diameter. CONCLUSIONS: Resistance has been lower or comparable on shortened tubes as compared to standard tubes.