scholarly journals VENTILAÇÃO CONTROLADA COM PRESSÃO EXPIRATÓRIA FINAL POSITIVA EM SUÍNOS ANESTESIADOS COM ISOFLURANO OU HALOTANO E SUBMETIDOS A PNEUMOPERITÔNIO OU PNEUMOTÓRAX COM CO2

2002 ◽  
Vol 7 (2) ◽  
Author(s):  
A. F. CUNHA ◽  
C. C. NATALINI ◽  
S. D. L ALVES ◽  
S. BOPP ◽  
J. F. FERREIRA ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Intrathoracic Pressure ◽  
Minute Volume ◽  
Abdominal Pressure ◽  
Positive End Expiratory Pressure ◽  
Controlled Ventilation ◽  
End Tidal Carbon Dioxide ◽  
Peep Ventilation ◽  
End Tidal ◽  
Mean Heart Rate

A homeostase hemodinâmica e respiratória nas vídeo cirurgias onde se emprega insuflação abdominal ou torácica requer métodos especiais de ventilação como a pressão expiratória final positiva (PEEP). Este experimento teve por objetivo avaliar a hemodinâmica e a oxigenação de suínos submetidos anestesia geral com isoflurano ou halotano onde foi realizado pneumoperitôneo a uma pressão constante de 15 mmHg ou pneumotórax de 5 mmHg com CO2 e ventilados com pressão expiratória zero ou 10 cm de H2O. Foram estudadas as variáveis pressão arterial (sistólica, média e diastólica), freqüência cardíaca e respiratória, saturação de oxigênio na hemoglobina (SpO2), volume corrente e minuto, eletrocardiografia e ainda pressão parcial de dióxido de carbono expirado. Onde foram observados valores de SpO2 mais elevados nos grupos submetidos a PEEP e maior hipotensão nos suínos anestesiados com halotano, nos permitindo concluir que quando comparado com o grupo que recebeu pressão expiratória final zero o uso de 10 cm de água de PEEP melhora a SpO2 e o isoflurano é superior ao halotano na manutenção da função cardiovascular de suínos submetidos à insuflação intra-abdominal ou intratorácica com CO2. Controlled ventilation with Positive End-Expiratory Pressure in isoflurane or halotane anesthetized pigs submitted to pneumoperitoneum or pneumothorax with CO2 Abstract Hemodynamic and respiratory homeostasy in the video surgeries need special ventilatory methods as positive end-expiratory pressure (PEEP). This study aimed to investigate the hemodynamic and oxygenation effects in isoflurane or halotane anesthetized pigs, submitted to constant 15 mm Hg CO2 abdominal pressure or 5 mm Hg CO2 intrathoracic pressure of 10 cm of H2O of PEEP or 0 cm of H2O (ZEEP). Variables studied were arterial pressure (systolic, diastolic and mean) heart rate, respiratory rate, SpO2, tidal volume, minute volume, electrocardiogram and expiratory end-tidal carbon dioxide. Were observed improved in SpO2 with 10 cm of H2O PEEP and more hypotension in the halotane anesthetized group. We conclude that when compared to ZEEP group, 10 cm of H2O PEEP ventilation improves SPO2, while isoflurane is better to maintain the cardiovascular function to anesthetized pigs submitted to 15 mm Hg intra-abdominal and 5 mm Hg intratoracic pressure insufflations with CO2.

scholarly journals The Influence of CO2 Production and Physiological Deadspace on End-Tidal CO2 During Controlled Ventilation: A Study Using a Mechanical Model

1989 ◽  
Vol 17 (4) ◽  
pp. 482-486 ◽  
Author(s):  
M. A. Stockwell ◽  
W. Bruce ◽  
N. Soni
Keyword(s):  
Carbon Dioxide ◽  
Mechanical Model ◽  
Carbon Dioxide Production ◽  
Lung Model ◽  
Co2 Production ◽  
Controlled Ventilation ◽  
End Tidal Carbon Dioxide ◽  
Carbon Dioxide Levels ◽  
End Tidal ◽  
End Tidal Co2

A mechanical lung model was used to investigate the effect of varying carbon dioxide production and deadspace on the end-tidal carbon dioxide levels achieved during mechanical ventilation when using the Bain, Humphrey ADE, and circle systems. Both factors had significant influence on end-tidal cardon dioxide concentration and could result in values in excess of those considered acceptable in clinical practice. The implications of the results are discussed.

scholarly journals Effects of PEEP on Hemodynamic Variables of Pigs Submitted to Volume-controlled Ventilation under Pneumoperitoneum associated to Cephalodeclive

2021 ◽  
Vol 49 ◽  
Author(s):  
Cléber Kazuo Ido ◽  
Newton Nunes
Keyword(s):  
Mechanical Ventilation ◽  
Cardiac Output ◽  
Intrathoracic Pressure ◽  
The Other ◽  
Abdominal Pressure ◽  
Positive End Expiratory Pressure ◽  
Controlled Ventilation ◽  
Hemodynamic Variables ◽  
Volume Controlled Ventilation ◽  
Volume Controlled

Background: Videolaparoscopic procedures have gained prominence due to their low invasiveness, causing less surgical trauma and better post-surgical recovery. However, the increase in intra-abdominal pressure due to the institution of pneumoperitoneum can alter the patient's homeostasis. Therefore, volume-controlled ventilation, associated with positive end-expiratory pressure (PEEP), improves arterial oxygenation and prevents pulmonary collapse, but it can lead to important hemodynamic changes. The aim of this study was to evaluate, comparatively, the effects of positive end expiratory-pressure (PEEP) on hemodynamic variables of pigs submitted to volume-controlled ventilation, during pneumoperitoneum and maintained in head-down tilt and determine which PEEP value promotes greater stability on hemodynamic variables. Materials, Methods & Results: Twenty-four pigs were used, between 55 and 65-day-old, weighing between 15 and 25 kg, randomly divided into 3 distinct groups differentiated by positive end-expiratory pressure: PEEP 0 (volume-controlled ventilation and PEEP of 0 cmH2O), PEEP 5 (volume-controlled ventilation and PEEP of 5 cmH2O) and PEEP 10 (volume-controlled ventilation and PEEP of 10 cmH2O). Volume-controlled ventilation was adjusted to 8 mL/kg of tidal volume and a respiratory rate of 25 movements per min. Anesthesia was maintained with continuous infusion of propofol (0.2 mg/kg/min) and midazolam (1 mg/kg/h). Pneumoperitoneum was performed with carbon dioxide (CO2), keeping the intra-abdominal pressure at 15 mmHg and the animals were positioned on a 30° head-down tilt. The evaluations of hemodynamic variables started 30 min after induction of anesthesia (M0), followed by measurements at 15-min intervals (from M15 to M90), completing a total of 7 evaluations. The variables of interest were collected over 90 min and submitted to analysis of variance followed by Tukey´s post-hoc test, with P < 0.05. The PEEP 10 group had higher values of CVP and mCPP, while the PEEP 5 group, mPAP and PVR were higher. The PEEP 0 group, on the other hand, had higher means of CI. Regarding the moments, there were differences in HR, SAP, DAP, MAP, CO, IC and TPR.Discussion: According to the literature, important hemodynamic effects due to pneumoperitoneum are reported, which can be caused by the pressure used in abdominal insufflation, CO2 accumulation, duration of the surgical procedure, hydration status and patient positioning. Mechanical ventilation associated with PEEP can also cause an increase in intrathoracic pressure and, therefore, reduce cardiac output. Cardiovascular changes are proportional to the PEEP used. Central venous pressure (PVC) measure the patient's preload, and intrathoracic pressure can interfere with this parameter. The peak pressure values in the PEEP 10 group were higher than the other groups, demonstrating that the increase in intrathoracic pressure results in higher PVC values. Regarding PAPm and PCPm, these variables can be influenced according to the PEEP values and the patient's position. In relation to CI, the increase in PEEP may reflect on intrathoracic pressure, resulting in greater compression of the heart, with a consequent reduction in cardiac output and cardiac index. Therefore, it is concluded that the PEEP effects of 0 cmH2O and 5 cmH2O on hemodynamics are discrete, under the proposed conditions. Keywords: mechanical ventilation, PEEP, head-down tilt, VCV, swine. Descritores: ventilação mecânica, PEEP, posição de Trendelenburg, suínos. 

scholarly journals Effect of positive end-expiratory pressure value on change in end-tidal carbon dioxide as a predictor of fluid responsiveness in Patients Undergoing Passive Leg Raising Maneuver

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Lutfi Nur Farid ◽  
Hardiono Hardiono ◽  
Pesta Parulian Maurid Edwar
Keyword(s):  
Carbon Dioxide ◽  
Cardiac Output ◽  
Fluid Responsiveness ◽  
Passive Leg Raising ◽  
Positive End Expiratory Pressure ◽  
Mechanically Ventilated ◽  
Resuscitation Room ◽  
End Tidal Carbon Dioxide ◽  
Before And After ◽  
End Tidal

Abstract  Identification of patients’ fluid status in the emergency room should be made before giving fluid therapy. This study aimed to determine the effect of positive end-expiratory pressure on change in end-tidal carbon dioxide during passive leg raising maneuver to predict fluid responsiveness. Thirty subjects aged 18-65 years in the resuscitation room, all on the ventilator, were divided into three groups according to their positive end-expiratory pressure value: low (0-5 cmH2O), moderate (6-10 cmH2O), and high (>10 cmH2O). Every subject underwent passive leg raising to simulate fluid administration. Values of blood pressure, heart rate, cardiac output, and end-tidal carbon dioxide were recorded before and after the maneuver. Analysis of the three groups found a significant correlation between change in end-tidal carbon dioxide with a cut-off value of 5% and 1 mmHg with fluid responsiveness of subjects in the low (p = 0.028) and moderate (p = 0.013) but not in the high positive end-expiratory pressure group (p = 0.333). In conclusion, change in end-tidal carbon dioxide in mechanically ventilated patients undergoing passive leg raising maneuvers can be used as a predictor of fluid responsiveness, but this method cannot be used on patients with high positive end-expiratory pressure (> 10 cmH2O) Keywords             : change in end tidal carbon dioxide, fluid responsiveness, positive end-expiratory pressure, passive leg raising, cardiac output surrogateCorrespondence   : [email protected]

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