General anesthesia, even in patients in good health, impairs gas exchanges and ventilatory mechanics. These effects result primarily from atelectasis formation. They occur in 85-90% of healthy patients in the minutes following the induction when a positive end expiratory pressure (PEEP) is not used. The functional residual capacity (FRC) of obese patients during general anesthesia is even smaller than the one of healthy patients. There is a direct relationship between the body mass index and the decrease of the functional residual capacity. Obese patients have therefore more atelectasis. The increased abdominal pressure during the pneumoperitoneum will increase the decrease of the CRF, and thus aggravate the formation of these atelectasis. Atelectasis affect the peroperative gas exchanges and are likely to be involved in the worsening of postoperative hypoxemia episodes. In addition, atelectasis alter the clearance of secretions and the lymph flow, which predispose to lung infections.Taking all these factors into account, it is logical to think that the atelectasis presence can lead to an increase of the postsurgical morbidity (respiratory distress, infections). That is why actively fighting against the formation of these atelectasis is important. There is a lack of scientific evidence to say that the strategies against atelectasis as PEEP have a significant impact on the patient's postoperative status. The expected clinical benefits balance (reduction of respiratory distress episodes, infections and mortality) versus the risks linked to the maneuvers done to reduce the development of atelectasis (barotraumas, cardiac complications) remains to be determined. The primary goal of this study is to evaluate the impact of two different alveolar recruitment strategies on the incidence of postoperative hypoxemia in obese patients after bariatric surgery. The secondary objectives of this study are to compare the number of recruitment maneuvers, the Pa02 / FI02 ratio (ratio of arterial oxygen partial pressure to fractional inspired oxygen), the dynamic compliance, the anatomic dead space and intraoperative PaCO2-EtCO2 gradient (arterial and end tidal gradient) between two alveolar recruitment strategies applied in obese patients during laparoscopic bariatric surgery (gastric bypass or sleeve gastrectomy). The tertiary objectives of this study are to report the number of respiratory complications and postoperative wound infections at the 30th postoperative day.
General anesthesia, even in patients in good health, impairs gas exchanges and ventilatory mechanics. These effects result primarily from atelectasis formation. They occur in 85-90% of healthy patients in the minutes following the induction when a positive end expiratory pressure (PEEP) is not used. These atelectasis are formed on one hand by the reduction of the functional residual capacity (FRC) following a compression mechanism (loss of the inspiratory muscle tone, which is accompanied by a chest wall configuration change and a diaphragm cephalic movement) and on the other hand by a denitrogenation absorption process (ventilation at high Fi02 (oxygen inspired fraction) causing complete absorption of O2 with lack of support for the alveolus, which then collapses). The FRC of obese patients during general anesthesia is even smaller than the one of healthy patients. There is a direct relationship between the body mass index and the decrease of the functional residual capacity. Obese patients have therefore more atelectasis. The increased abdominal pressure during the pneumoperitoneum will increase the decrease of the CRF, and thus aggravate the formation of these atelectasis. Atelectasis affect the peroperative gas exchanges and are likely to be involved in the worsening of postoperative hypoxemia episodes. In addition, atelectasis alter the clearance of secretions and the lymph flow, which predispose to lung infections.Taking all these factors into account, it is logical to think that the atelectasis presence can lead to an increase of the postsurgical morbidity (respiratory distress, infections). That is why actively fighting against the formation of these atelectasis is important. Several strategies have been studied in order to improve respiratory mechanics and reduce impaired gas exchange during laparoscopic surgery in obese patients. The position called "chair", mechanical ventilation with PEEP, recruitment maneuvers followed by the PEEP, and spontaneous ventilation with CPAP before extubation, are all strategies that have proven effective to decrease development these atelectasis. Currently, the scientific community agrees on the fact that PEEP improves intraoperative respiratory function (improved compliance, oxygenation) especially in conjunction with recruitment maneuvers. But there is a lack of scientific evidence to say that the strategies against atelectasis as PEEP have a significant impact on the patient's postoperative status. The expected clinical benefits balance (reduction of respiratory distress episodes, infections and mortality) versus the risks linked to the maneuvers done to reduce the development of atelectasis (barotraumas, cardiac complications) remains to be determined. The primary goal of this study is to evaluate the impact of two different alveolar recruitment strategies on the incidence of postoperative hypoxemia in obese patients after bariatric surgery. The secondary objectives of this study are to compare the number of recruitment maneuvers, the Pa02 / FI02 ratio, the dynamic compliance, the anatomic dead space and intraoperative PaCO2-EtCO2 gradient between two alveolar recruitment strategies applied in obese patients during laparoscopic bariatric surgery (gastric bypass or sleeve gastrectomy). The tertiary objectives of this study are to report the number of respiratory complications and postoperative wound infections at the 30th postoperative day.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
100
CHU Brugmann
Brussels, Belgium
Number of hypoxemia episodes (Sp02<90%)
This will be monitored by a portable saturometer (OxyTrue A, Bluepoint, Germany). This saturometer will allow the investigators to count the number of hypoxemia episodes (Sp02\<90%) and their duration in obese patients, in the postoperative period.
Time frame: continuously during 48h after surgery
Number of hypoxemia episodes (Sp02<95%)
This will be monitored by a portable saturometer (OxyTrue A, Bluepoint, Germany). This saturometer will allow the investigators to count the number of hypoxemia episodes (Sp02\<95%) and their duration in obese patients, in the postoperative period.
Time frame: continuously during 48h after surgery
Number of recruitment manoeuvers
Recruitment manoeuver are performed if patient saturation drops below 95%.
Time frame: From the beginning of the surgery till moment 1 (after induction/intubation, patient laying flat, without pneumoperitoneum)
Number of recruitment manoeuvers
Recruitment manoeuver are performed if patient saturation drops below 95%.
Time frame: From moment 1 till moment 2 (after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation)
Number of recruitment manoeuvers
Recruitment manoeuver are performed if patient saturation drops below 95%.
Time frame: From moment 2 till moment 3 (after pneumoperitoneum exsufflation - patient lying flat)
Number of recruitment manoeuvers
Recruitment manoeuver are performed if patient saturation drops below 95%.
Time frame: From moment 3 till the end of the surgery (patient leaving the theater)
Pulmonary dynamic compliance (Cd) - preoperative
This will be determined by the following formula: Cd = Vt/P(peak)-PEEP and expressed in mL/cmH2O
Time frame: Just before surgery, at ambient air contact
Pulmonary dynamic compliance (Cd) - moment 1
This will be determined by the following formula: Cd = Vt/P(peak)-PEEP and expressed in mL/cmH2O
Time frame: just after the anesthesia induction/intubation, patient laying flat, without pneumoperitory
Pulmonary dynamic compliance (Cd) -moment 2
This will be determined by the following formula: Cd = Vt/P(peak)-PEEP and expressed in mL/cmH2O
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Pulmonary dynamic compliance (Cd) -moment 3
This will be determined by the following formula: Cd = Vt/P(peak)-PEEP and expressed in mL/cmH2O
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Pulmonary dynamic compliance (Cd) -if recruitment manoeuvers
This will be determined by the following formula: Cd = Vt/P(peak)-PEEP and expressed in mL/cmH2O
Time frame: Five minutes after any recruitment manoeuver
Anatomic dead space - preoperative
This will be determined by this formula: VD = VT (1-PEtCO2/PaC02)
Time frame: Just before surgery, at ambient air contact
Anatomic dead space -moment 1
This will be determined by this formula: VD = VT (1-PEtCO2/PaC02)
Time frame: just after the anesthesia induction/intubation, patient laying flat, without pneumoperitory
Anatomic dead space -moment 2
This will be determined by this formula: VD = VT (1-PEtCO2/PaC02)
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Anatomic dead space -moment 3
This will be determined by this formula: VD = VT (1-PEtCO2/PaC02)
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Anatomic dead space -if recruitment manoeuvers
This will be determined by this formula: VD = VT (1-PEtCO2/PaC02)
Time frame: Five minutes after any recruitment manoeuver
PaO2/FiO2 ratio - preoperative
Arterial oxygen partial pressure to fractional inspired oxygen ratio
Time frame: Just before surgery, at ambient air contact
PaO2/FiO2 ratio - moment 1
Arterial oxygen partial pressure to fractional inspired oxygen ratio
Time frame: just after the anesthesia induction/intubation, patient laying flat, without pneumoperitory
PaO2/FiO2 ratio - moment 2
Arterial oxygen partial pressure to fractional inspired oxygen ratio
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
PaO2/FiO2 ratio - moment 3
Arterial oxygen partial pressure to fractional inspired oxygen ratio
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
PaO2/FiO2 ratio - if recruitment manoeuvers
Arterial oxygen partial pressure to fractional inspired oxygen ratio
Time frame: Five minutes after any recruitment manoeuver
PaCO2-EtCO2 gradient - preoperative
The gradient between the partial pressure of carbon dioxide in the arterial blood (PaCO2) and the CO2 end-tidal partial pressure (EtCO2) is used to evaluate the effectiveness of alveolar recruitment.
Time frame: Just before surgery, at ambient air contact
PaCO2-EtCO2 gradient - moment 1
The gradient between the partial pressure of carbon dioxide in the arterial blood (PaCO2) and the CO2 end-tidal partial pressure (EtCO2) is used to evaluate the effectiveness of alveolar recruitment.
Time frame: just after the anesthesia induction/intubation, patient laying flat, without pneumoperitory
PaCO2-EtCO2 gradient - moment 2
The gradient between the partial pressure of carbon dioxide in the arterial blood (PaCO2) and the CO2 end-tidal partial pressure (EtCO2) is used to evaluate the effectiveness of alveolar recruitment.
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
PaCO2-EtCO2 gradient - moment 3
The gradient between the partial pressure of carbon dioxide in the arterial blood (PaCO2) and the CO2 end-tidal partial pressure (EtCO2) is used to evaluate the effectiveness of alveolar recruitment.
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
PaCO2-EtCO2 gradient - if recruitment manoeuvers
The gradient between the partial pressure of carbon dioxide in the arterial blood (PaCO2) and the CO2 end-tidal partial pressure (EtCO2) is used to evaluate the effectiveness of alveolar recruitment.
Time frame: Five minutes after any recruitment manoeuver
Number of respiratory complications
Number of hospitalisations due to respiratory complications within 30 days after surgery.
Time frame: 30 days after surgery
Number of postoperative wound infections
All patients are seen at the surgical consultation on day 30 after surgery. The anamnesis performed during that consultation enables the investigators to identify patients with wound infections (defined as a need for local or oral antibiotics, additional hospitalisation or abnormal cicatrisation).
Time frame: 30 days after surgery
Pre-operative physiologic measures: cardiac frequency (FC)
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: Just before surgery, at ambient air contact
Pre-operative physiologic measures: Arterial tension (TA)
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: Just before surgery, at ambient air contact
Pre-operative physiologic measures: pH
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: Just before surgery, at ambient air contact
Pre-operative physiologic measures: partial pressure of carbon dioxide in the arterial blood (PaCO2)
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens).
Time frame: Just before surgery, at ambient air contact
Operative physiologic measures - moment 1: FC
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 1: PAM (Average arterial pressure)
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 1: pH
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 1: PaCO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 1: CO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 2: FC
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 2: PAM
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 2: pH
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 2: PaCO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 2: CO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 3: FC
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Operative physiologic measures - moment 3: PAM
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Operative physiologic measures - moment 3: pH
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Operative physiologic measures - moment 3: CO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Operative physiologic measures - moment 3: PaCO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Operative physiologic measures - if recruitment manoeuvers occurs: FC
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: Five minutes after any recruitment manoeuver
Operative physiologic measures - if recruitment manoeuvers occurs: PAM
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: Five minutes after any recruitment manoeuver
Operative physiologic measures - if recruitment manoeuvers occurs: SpO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: Five minutes after any recruitment manoeuver
Operative physiologic measures - if recruitment manoeuvers occurs: pH
The hemodynamic and respiratory parameters of the patient are measured by means of a Datex-Ohmeda Acertys machine (Aisys type).
Time frame: Five minutes after any recruitment manoeuver
Operative physiologic measures - if recruitment manoeuvers occurs: PaCO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: Five minutes after any recruitment manoeuver
Operative physiologic measures - if recruitment manoeuvers occurs: PaO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: Five minutes after any recruitment manoeuver
Operative physiologic measures - if recruitment manoeuvers occurs: CO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: Five minutes after any recruitment manoeuver
Pre-operative physiologic measures: partial pressure of oxygen in the arterial blood (PaO2)
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: Just before surgery, at ambient air contact
Operative physiologic measures - moment 1: PaO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 2: PaO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 3: PaO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
Pre-operative physiologic measures: Oxygen Pulsated Saturation (SpO2)
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: Just before surgery, at ambient air contact
Operative physiologic measures - moment 1: SpO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after induction/intubation, patient laying flat, without pneumoperitoneum
Operative physiologic measures - moment 2: SpO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after peritoneal insufflation and anti-trendenlenbourg (anti-trent) implementation
Operative physiologic measures - moment 3: SpO2
The gasometric parameters of the patient are analyzed with a Rapidlab 1265 machine (Siemens)
Time frame: just after pneumoperitoneum exsufflation - patient lying flat
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