PEEP-ZEEP technique: cardiorespiratory repercussions in mechanically ventilated patients submitted to a coronary artery bypass graft surgery

<p>Abstract</p> <p>Background</p> <p>The PEEP-ZEEP technique is previously described as a lung inflation through a positive pressure enhancement at the end of expiration (PEEP), followed by rapid lung deflation with an abrupt reduction in the PEEP to 0 cmH₂O (ZEEP), associated to a manual bilateral thoracic compression.</p> <p>Aim</p> <p>To analyze PEEP-ZEEP technique's repercussions on the cardio-respiratory system in immediate postoperative artery graft bypass patients.</p> <p>Methods</p> <p>15 patients submitted to a coronary artery bypass graft surgery (CABG) were enrolled prospectively, before, 10 minutes and 30 minutes after the technique. Patients were curarized, intubated, and mechanically ventilated. To perform PEEP-ZEEP technique, saline solution was instilled into their orotracheal tube than the patient was reconnected to the ventilator. Afterwards, the PEEP was increased to 15 cmH₂O throughout 5 ventilatory cycles and than the PEEP was rapidly reduced to 0 cmH₂O along with manual bilateral thoracic compression. At the end of the procedure, tracheal suction was accomplished.</p> <p>Results</p> <p>The inspiratory peak and plateau pressures increased during the procedure (p < 0.001) compared with other pressures during the assessment periods; however, they were within lung safe limits. The expiratory flow before the procedure were 33 ± 7.87 L/min, increasing significantly during the procedure to 60 ± 6.54 L/min (p < 0.001), diminishing to 35 ± 8.17 L/min at 10 minutes and to 36 ± 8.48 L/min at 30 minutes. Hemodynamic and oxygenation variables were not altered.</p> <p>Conclusion</p> <p>The PEEP-ZEEP technique seems to be safe, without alterations on hemodynamic variables, produces elevated expiratory flow and seems to be an alternative technique for the removal of bronchial secretions in patients submitted to a CABG.</p

Propensity score matching comparison of laparoscopic versus open surgery for rectal cancer in a middle-income country: short-term outcomes and cost analysis

Daiane Oliveira Tayar,1 Ulysses Ribeiro Jr,2 Ivan Cecconello,2 Tiago M Magalh&atilde;es,3 Claudia M Sim&otilde;es,4 Jos&eacute; Ot&aacute;vio C Auler Jr1 1Department of Anesthesia and Critical Care, University of S&atilde;o Paulo, Faculty of Medicine, S&atilde;o Paulo, Brazil; 2Department of Gastroenterology, University of S&atilde;o Paulo, Faculty of Medicine, S&atilde;o Paulo, Brazil; 3Department of Statistics, Institute of Exact Sciences, Federal University of Juiz de Fora, Juiz de Fora, Brazil; 4Department of Anesthesia and Critical Care, Cancer Institute of the State of S&atilde;o Paulo, S&atilde;o Paulo, Brazil Background: Laparoscopic surgery for rectal cancer is associated with improved postoperative outcomes compared to open surgery; however, economic studies have yielded contradictory results. The aim of this study was to compare the clinical and economic outcomes of laparoscopic versus open surgery for patients with rectal cancer.Methods: Propensity score matching analysis was performed in a retrospective cohort of patients who underwent elective low anterior resection for rectal cancer treatment by laparoscopic and open surgery in a single Brazilian cancer center. Matched covariates included age, gender, body mass index, pTNM stage, American Society of Anesthesiologists score, type of anesthesia, neoadjuvant chemoradiotherapy, and interval between neoadjuvant chemoradiotherapy and index surgery. The clinical and economic outcomes were evaluated. The follow-up period was within 30 days of the index procedure. The clinical outcomes were reoperation, postoperative complications, operative time, length of stay in the intensive care unit, and postoperative hospital stay. For economic outcomes, a cost analysis was used to compare the costs.Results: Initially, 220 patients were evaluated. After propensity score matching, 100 patients were included in the analysis (50 patients in the open surgery group and 50 patients in the laparoscopic surgery group). There were no differences in patients&rsquo; baseline characteristics. Operative time was longer for laparoscopic surgery (247 minutes vs 285 minutes, P=0.006). There were no significant differences in other clinical outcomes. The hospital costs were similar between the two groups (Brazilian reais 21,233.15 vs Brazilian reais 21,529.28, P=0.115), although the intraoperative costs were higher for laparoscopic surgery, mainly owing to the surgical devices and the theater-related costs. The postoperative costs were lower for laparoscopic surgery, owing to lower intensive care unit, ward, and reoperation costs.Conclusion: Laparoscopic surgery for rectal cancer is not costlier than open surgery from the health care provider&rsquo;s perspective, since the intraoperative costs were offset by lower postoperative costs. Open surgery tends to have a longer length of stay. Keywords: rectal cancer, laparoscopy, open surgery, propensity score matching, health care costs, cost analysi

The effects of positive end-expiratory pressure on respiratory system mechanics and hemodynamics in postoperative cardiac surgery patients

We prospectively evaluated the effects of positive end-expiratory pressure (PEEP) on the respiratory mechanical properties and hemodynamics of 10 postoperative adult cardiac patients undergoing mechanical ventilation while still anesthetized and paralyzed. The respiratory mechanics was evaluated by the inflation inspiratory occlusion method and hemodynamics by conventional methods. Each patient was randomized to a different level of PEEP (5, 10 and 15 cmH2O), while zero end-expiratory pressure (ZEEP) was established as control. PEEP of 15-min duration was applied at 20-min intervals. The frequency dependence of resistance and the viscoelastic properties and elastance of the respiratory system were evaluated together with hemodynamic and respiratory indexes. We observed a significant decrease in total airway resistance (13.12 ± 0.79 cmH2O l-1 s-1 at ZEEP, 11.94 ± 0.55 cmH2O l-1 s-1 (P<0.0197) at 5 cmH2O of PEEP, 11.42 ± 0.71 cmH2O l-1 s-1 (P<0.0255) at 10 cmH2O of PEEP, and 10.32 ± 0.57 cmH2O l-1 s-1 (P<0.0002) at 15 cmH2O of PEEP). The elastance (Ers; cmH2O/l) was not significantly modified by PEEP from zero (23.49 ± 1.21) to 5 cmH2O (21.89 ± 0.70). However, a significant decrease (P<0.0003) at 10 cmH2O PEEP (18.86 ± 1.13), as well as (P<0.0001) at 15 cmH2O (18.41 ± 0.82) was observed after PEEP application. Volume dependence of viscoelastic properties showed a slight but not significant tendency to increase with PEEP. The significant decreases in cardiac index (l min-1 m-2) due to PEEP increments (3.90 ± 0.22 at ZEEP, 3.43 ± 0.17 (P<0.0260) at 5 cmH2O of PEEP, 3.31 ± 0.22 (P<0.0260) at 10 cmH2O of PEEP, and 3.10 ± 0.22 (P<0.0113) at 15 cmH2O of PEEP) were compensated for by an increase in arterial oxygen content owing to shunt fraction reduction (%) from 22.26 ± 2.28 at ZEEP to 11.66 ± 1.24 at PEEP of 15 cmH2O (P<0.0007). We conclude that increments in PEEP resulted in a reduction of both airway resistance and respiratory elastance. These results could reflect improvement in respiratory mechanics. However, due to possible hemodynamic instability, PEEP should be carefully applied to postoperative cardiac patients

Videolaparoscopic cholecystectomy. Analysis of the clinical and functional aspects of mechanical lifting of the abdominal wall Colecistectomia videolaparoscópica. Análise de aspectos clínicos e funcionais da suspensão mecânica da parede abdominal

Background - Mechanical lifting of the abdominal wall, a method based on traction and consequent elevation of the abdominal wall, is an alternative procedure to create enough intra-abdominal space necessary for videolaparoscopic surgery, dispensing the need for intraperitoneal gas insufflation. Objective - This study aims to evaluate the technical feasibilility of this procedure to carry out a videolaparoscopic cholecystectomy, while analyzing the clinical and functional aspects of this technique. Patients and Methods - In the Digestive Tract Surgery Discipline of the Medical School at the University of São Paulo, São Paulo, SP, Brazil, was created the equipment to perform videolaparoscopic surgery using this method. The equipment has two sections: an external part which consisted of a frame attached to the operating table, inside which there is a sliding steel cable, moved by a ratched which is located at the lower end of one of the frame rods; the internal rod, the support, has an "L" shape, and its horizontal branch is made up of three turning rods and which is connected to the steel cable after insertion into the abdominal cavity. Ten patients underwent videolaparoscopic cholecystectomy using this equipment. The time taken to install the equipment, the operating area characteristics, the interference from the lifting equipment on surgical movements and on the intra-operative cholangiography, the measurements made of the force used during traction and extension of the abdominal wall elevation, and the medication required for post-operative analgesia were all evaluated. Results - There were no intra-operative complications, and in none of the cases was it found necessary to convert to open surgery. We considered the insertion a safe and uncomplicated procedure, and the traction system efficient. Apart from the elevation of the abdominal wall, the distribution of the viscera inside the abdominal cavity is fundamental for the operating area. Depending on the position of the epigastric trocar, the lifting equipment can interfere with the surgical instruments mobility. It may be necessary to reposition the support to perform the intra-operative cholangiography. The tensional force applied to the peritoneal surface by the lifting rods is small, and no additional post-operative pain was observed using this procedure. Conclusion - These results show that using the equipment described in this study, mechanical lifting of the abdominal wall is a feasible alternative for undertaking videolaparoscopic cholecystectomy.<br>Racional - A suspensão mecânica da parede abdominal, método baseado no mecanismo de tração e conseqüente elevação da parede abdominal, é procedimento alternativo para a criação de adequado espaço intra-abdominal necessário à cirurgia videolaparoscópica, prescindindo-se da insuflação gasosa intra-peritonial. Objetivo - Avaliar a viabilidade técnica desse procedimento para realização da colecistectomia videolaparoscópica, com a análise de aspectos clínicos e funcionais da suspensão mecânica da parede abdominal. Pacientes e Métodos - Na Disciplina de Cirurgia do Aparelho Digestivo da Faculdade de Medicina da Universidade de São Paulo foi criado equipamento para realização de cirurgia videolaparoscópica por esse método, constituído de duas partes: a externa consiste em um pórtico acoplado à mesa operatória, no interior do qual desliza um cabo de aço que é tracionado por um sistema de catraca presente na extremidade inferior de uma das hastes do pórtico; a interna, o dispositivo suspensor, tem o formato em "L", cujo ramo horizontal é constituído de três hastes giratórias, o qual é conectado ao cabo de aço após introdução na cavidade abdominal. Com esse equipamento 10 pacientes foram submetidos a colecistectomia videolaparoscópica; em um deles foi associada hiatoplastia e fundoplicatura. Foram avaliados o tempo de instalação do equipamento, as características do campo operatório, a interferência provocada pela presença do equipamento de suspensão nos movimentos operatórios e nas imagens da colangiografia intra-operatória; foram medidas a força aplicada na tração e a extensão da elevação da parede abdominal e, por fim, a necessidade de medicação para analgesia pós-operatória. Resultados - Não houve qualquer complicação intra-operatória, não sendo necessária conversão para cirurgia aberta em nenhum caso. Observou-se facilidade e segurança na introdução do suspensor, bem como eficácia do sistema de tração. No campo operatório, além da elevação da parede abdominal, desempenha papel fundamental o nível de distribuição das vísceras no interior da cavidade. Dependendo da posição do trocarte epigástrico, a presença do equipamento de suspensão pode interferir na movimentação dos instrumentos. Para realização da colangiografia intra-operatória pode ser necessário o reposicionamento do suspensor. É pequena a força tensional aplicada na superfície peritoneal pelas hastes do suspensor, não se observando qualquer indicativo de maior dor pós-operatória com esse procedimento. Conclusão - Em face desses resultados, a suspensão mecânica da parede abdominal, realizada com o equipamento descrito nesse trabalho, é alternativa viável para realização da colecistectomia videolaparoscópica