Carta al editor: Manual de práctica clínica basado en la evidencia: preparación del paciente para el acto quirúrgico y traslado al quirófano / Letter to the Editor: Evidence based clinical practice manual: Patient preparation for surgery and transfer to the operating room

Letter to the Editor

Comparison of two protective lung ventilatory regimes on oxygenation during one-lung ventilation: a randomized controlled trial.

BACKGROUND: The efficacy of protective ventilation in acute lung injury has validated its use in the operating room for patients undergoing thoracic surgery with one-lung ventilation (OLV). The purpose of this study was to investigate the effects of two different modes of ventilation using low tidal volumes: pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on oxygenation and airway pressures during OLV. METHODS: We studied 41 patients scheduled for thoracoscopy surgery. After initial two-lung ventilation with VCV patients were randomly assigned to one of two groups. In one group OLV was started with VCV (tidal volume 6 mL/kg, PEEP 5) and after 30 minutes ventilation was switched to PCV (inspiratory pressure to provide a tidal volume of 6 mL/kg, PEEP 5) for the same time period. In the second group, ventilation modes were performed in reverse order. Airway pressures and blood gases were obtained at the end of each ventilatory mode. RESULTS: PaO2, PaCO2 and alveolar-arterial oxygen difference did not differ between PCV and VCV. Peak airway pressure was significantly lower in PCV compared with VCV (19.9 ± 3.8 cmH2O vs 23.1 ± 4.3 cmH2O; p < 0.001) without any significant differences in mean and plateau pressures. CONCLUSIONS: In patients with good preoperative pulmonary function undergoing thoracoscopy surgery, the use of a protective lung ventilation strategy with VCV or PCV does not affect the oxygenation. PCV was associated with lower peak airway pressures.

Intubación orotraqueal sin relajante muscular: propofol o etomidato en combinación con remifentanilo / Orotracheal Intubation without the use of muscle relaxant: propofol or etomidate in combination with remifentanil

Introducción. El remifentanilo en combinación con propofol provee adecuadas condiciones para la intubación orotraqueal sin relajante neuromuscular. Otros agentes inductores no han sido adecuadamente evaluados. El propósito del estudio fue evaluar las condiciones de intubación y los cambios hemodinámicos tras la inducción anestésica con remifentanilo-propofol o remifentanilo- etomidato. Métodos. En este estudio prospectivo, doble ciego y aleatorio, participaron 90 pacientes con clasificación ASA I/II. Recibieron 0,03 mg/kg de midazolam y 7 ml/kg de lactato de Ringer, y posteriormente, 3 mg/kg de remifentanilo seguidos de 1 mg/kg de lidocaína. A continuación, se distribuyeron en forma aleatoria en los siguientes grupos de pacientes: los que recibieron 2 mg/kg de propofol (grupo propofol, n=29), 0,3 mg/ kg de etomidato (grupo etomidato 3, n=31) o 0,4 mg/kg de etomidato (grupo etomidato 4, n=30). Después se realizó laringoscopia e intubación orotraqueal. Las condiciones para la intubación se evaluaron utilizando un sistema cualitativo de puntaje. Se registraron la presión arterial media y la frecuencia cardiaca previa a la inducción, posterior a la inducción, inmediatamente después de la intubación y cada minuto hasta 5 minutos después de la intubación. Resultados. Tres pacientes del grupo etomidato 3 y dos del grupo etomidato 4 no pudieron ser intubados en el primer intento. Se alcanzaron condiciones clínicamente aceptables de intubación en 100%, 74% y 80%, en los grupo propofol, etomidato 3 y etomidato 4, respectivamente (p=0,016). El descenso en la presión arterial media fue significativamente mayor en el grupo propofol comparado con el grupo etomidato 3. Conclusiones. Para la intubación orotraqueal sin relajante neuromuscular, el uso de remifentanilo-propofol es superior al de remifentanilo-etomidato, 0,3 mg/kg o 0,4 mg/kg. Con 0,3 mg/kg de etomidato se obtiene un mejor perfil hemodinámico.

Introduction: Remifentanil followed by propofol provides adequate conditions for tracheal intubation without using muscle relaxants. Other hypnotic drugs have not been thoroughly evaluated in this regard. The purpose of this study was to assess intubating conditions and cardiovascular changes after induction of anesthesia with remifentanil-propofol or. Methods: 90 ASA I/II patients were enrolled in this random, prospective, double-blind study. Subjects received 0.03 mg/kg of midazolam followed by a 7 ml/kg infusion of RingerLs lactate. After that, 3 ƒÊg/kg of remifentanil were injected followed by lydocaine, 1 mg/kg. Then, patients received either propofol (2 mg/ kg) (Propofol Group, n= 29), or etomidate (0.3 mg/kg) (Etomidate 3 Group, n=31) or etomidate (0.4 mg/kg) (Etomidate 4 Group, n=30). Subsequent laryngoscope and intubation were performed. Intubating conditions were assessed using a quality scoring system. Mean arterial pressure and heart rates pre-induction, post-induction were recorded immediately after intubation and every 1 to 5 minutes after intubation. Results: Three patients in the etomidate 3 Group and two patients in the etomidate 4 Group were not able to beintubated in the first attempt. Clinically acceptable intubating conditions were observed in 100%, 74%, 80% in the Propofol, Etomidate 3 and etomodate 4 groups, respectively (p=0.01 6). The decrease in mean arterial pressure was significantly higher in the propofol group as compared to the etomidate 3 group (p<0.05). Conclusions: The use of lydocaine-remifentanil-propofol for tracheal intubation without muscle relaxants is superior to 0.3 or 0.4 mg/kg lydocaine-remifentanil plus etomidate. However, etomidate 0.3 mg/kg produces a better hemodynamic profile when compared to propofol.

Disfunción renal en postoperatorio de cirugía cardíaca pediátrica con circulación extracorpórea / Renal dysfunction in postoperative of pediatric heart surgery with circulation extracorpórea

Objetivos: La disfunción renal en el postoperatorio de la cirugía cardiaca continúa aumentando la morbilidad, mortalidad y costos. Aunque se han realizado múltiples estudios, los factores asociados a esta no están claros en el grupo pediátrico. El propósito del estudio es determinar la incidencia de disfunción renal postoperatoria, factores de riesgo para su desarrollo, su asociación a la mortalidad y las estancias hospitalarias. Métodos: Se estudiaron de forma prospectiva 236 pacientes, menores de 12 años de llevados a cirugía cardiaca con circulación extracorpórea entre el 1 de mayo del 2000 y el 31 de julio del 2003. Fueron excluidos los pacientes llevados a cierre de CIA y los que fallecieron en las primeras 24 horas. Se evaluó la asociación de las variables pre, trans y postoperatorias al desarrollo de disfunción o falla renal por medio de análisis univariado y multivariado. Se definió disfunción como valores anormales de depuración de creatinina para la edad, aumento del 25 por ciento de la creatinina basal u oliguria y falla como el requerimiento de diálisis. Resultados: De los 236 pacientes el 72 por ciento presento disfunción renal y 4,2 por ciento desarrolló falla renal. La única variable asociada al desarrollo de disfunción renal fue el hematocrito postoperatorio con una relación positiva: P = 0.001. Conclusiones: La disfunción renal esta asociada de forma independiente con la mortalidad postoperatoria de estos pacientes y con el aumento de las estancias en UCI y la estancia hospitalaria...

Endotracheal intubation with a lightwand or a laryngoscope results in similar hemodynamic variations in patients with coronary artery disease.

PURPOSE: To asses the cardiovascular changes after either lightwand or conventional laryngoscopic endotracheal intubation (EI) in patients with coronary artery disease. METHODS: Following Institutional approval and informed consent, 80 consecutive patients undergoing elective coronary artery bypass grafting were enrolled in this prospective, controlled, single-blinded study. General anesthesia was induced with fentanyl 5 micro x kg(-1) and thiopental 5 mg x kg(-1) followed by pancuronium 0.1 mg x kg(-1). After loss-of-eyelash reflex the lungs were manually ventilated with 2% isoflurane in oxygen for five minutes. Patients were then randomly allocated to receive either the lightwand (lightwand group, n = 41) or direct-vision laryngoscopy (laryngoscopy group, n = 39). Heart rate (HR) and direct blood pressure were recorded before induction, after induction but before EI, during EI, immediately after EI and at ten-second intervals for the following five minutes. Hemodynamic management during induction was standardized. Hypotension was treated with volume replacement, ephedrine, or phenylephrine as indicated; hypertension was treated with iv nitroglycerin; tachycardia was treated with boluses of esmolol; and, bradycardia was treated with atropine or ephedrine. RESULTS: In both groups, mean arterial blood pressures and HR increased significantly after EI. There was a tendency for the lightwand group to have lower arterial blood pressures and slower HR. However, the differences between the two groups did not reach statistical significance. Requirements for drugs to control HR and mean arterial pressure were similar in both groups. CONCLUSION: In patients with coronary artery disease using a lightwand intubation technique does not modify the hemodynamic response associated with EI as compared with standard direct-vision laryngoscopy.

Comparacion de las estrategias tradicionales y la teoria de Stewart en la interpretacion de las alteraciones acido-basicas en pacientes pediatricos con disfuncion multiorganica en el postoperatorio de cirugia cardiaca / Comparison of the traditional strategy of acid-basic analysis with the novel Steward's theory in pediatric patients with multiorganic dysfunction undergoing cardiac surgery

Objetivo: Comparar las estrategias tradicionales del análisis ácido-básico con la teoría de Stewart en pacientes pediátricos con disfunción multiorgánica en postoperatorio de cirugía cardiaca. Materiales y métodos: Estudio observacional analítico de cohorte concurrente, realizado en 66 pacientes pediátricos sometidos a circulación extracorporea (CEC) con una técnica estándar. En el postoperatorio inmediato se tomo muestra arterial para realizar el análisis ácido-básico tradicional y según Stewart; se aplicó diariamente la escala SOFA de disfunción orgánica durante tres días y se obtuvieron los valores mas altos. Los pacientes se dividieron en dos grupos de acuerdo a quienes presentaron falla orgánica (SOFA > 7; 20 pacientes) y sin falla orgánica (SOFA < 7; 46 pacientes). Resultados y conclusiones: El análisis tradicional en los pacientes que no desarrollaron falla mostró acidosis metabólica (pH 7.36 +/- 0.08, HCO3 16.6 +/- 2.6, BE -6.03 +/- 3.5). Los pacientes que desarrollaron falla mostraron resultados normales (pH 7.39 +/-0.08, HCO3 17.9+/-2.1, BE-4.8+/-2.6). El análisis de Stewart evidenció una mayor aparición de aniones anormales en los pacientes que desarrollaron falla (-4.2 vs -2.6), además sugiere que la acidosis evidenciada en los pacientes sin falla se explica por los cambios en la concentración de cloro y sodio producidos por la CEC

Comparison of total intravenous anesthesia and sevoflurane-fentanyl anesthesia for outpatient otorhinolaryngeal surgery.

STUDY OBJECTIVE: To compare the recovery characteristics of two widely used anesthetic techniques: remifentanyl-propofol and sevoflurane-fentanyl in a standardized ambulatory population. DESIGN: Randomized, single-blinded study. SETTING: University-affiliated medical center. PATIENTS: 50 ASA physical status I and II patients undergoing elective ambulatory otorhinolaryngeal surgery. INTERVENTIONS: Patients were randomized two groups to receive total intravenous anesthesia (TIVA group) with remifentanil and propofol or sevoflurane-fentanyl (SF group). TIVA patients received induction with propofol 1.5 mg/kg intravenously (IV) and remifentanil 0.5 microg/kg IV. The anesthesia was continued with a continuous infusion of propofol 100 microg/kg/min and remifentanil 0.0625-0.25 microg/kg/min. The SF group received, at induction, fentanyl 2 microg/kg followed by propofol 1.5 mg/kg IV. Maintenance was obtained with 1 to 1.5 minimum alveolar concentration of sevoflurane and bolus of fentanyl 1 microg/kg IV as needed. MEASUREMENTS AND MAIN RESULTS: Early recovery times (eye opening, response to commands, extubation, orientation, operating room stay after surgery, and Aldrete score > or =9) and patient satisfaction were similar between the two groups. Postanesthetic discharge scoring system (PADSS) > or = 9 was significantly shorter for the TIVA group (135.9 +/- 51 vs. 103 +/- 32 min) (p < 0.01) but this difference was not associated with a shorter postanesthesia care unit (PACU) length of stay. CONCLUSION: Early recovery times are comparable between total intravenous anesthesia and sevoflurane-based anesthesia. Even though patients in the TIVA group achieved home readiness criteria in a significantly shorter time, this technique does not shorten PACU length of stay, which depends instead on multiple nonmedical and administrative issues.

Cirugía cardíaca en un Paciente sospechoso de hipertermia maligna

Presentamos el manejo de anestésico de un paciente sospechoso de hipertermia maligna que requirió circulación extracorpórea para revascularización miocárdica. Descubrimos la preparación preoperatoria de la máquina de anestesia, la bomba de circulación extracorpórea y la controversia de la profilaxis con dantrolene en este caso específico. Otros aspectos controvertidos son el uso de inotrópicos y el manejo hemodinámico