Pneumoperitoneum and Cerebral Oxygenation
Condition: Laparoscopic Nephrectomy; Cerebral Oxygen Saturation
MeSH terms: Pneumoperitoneum
Study type: Interventional

Summary: 
      In this study, the changes in cerebral oxygen saturation due to low and high pressure
      pneumoperitoneum implementation were measured in patients who underwent laparoscopic
      nephrectomy. This prospective, double-blind study included 62 American Society of
      Anesthesiologists (ASA) PS class I-III patients aged 18-65 years who underwent laparoscopic
      nephrectomy (simple, partial, or radical). Patients were randomly classified into 2 groups:
      Group LP (n = 31) included patients who were treated with low pressure pneumoperitoneum (8
      mmHg) and Group SP (n = 31) included patients who were treated with standard pressure (14
      mmHg). A standard anesthesia protocol was used in both groups. Bilateral rSO2 values were
      recorded at baseline, at 1 minute after induction, and then every 5 minutes until the patient
      went to the recovery unit. Data for mean arterial pressure (MAP), peak heart rate (HR),
      peripheral oxgen saturation (SpO2), and end-tidal carbon dioxide (ETCO2) were also recorded
      at the same time intervals. Arterial blood gas was analyzed in the 5th minute after induction
      (t1) while the patient was in the supine position, in the 5th and 30th minutes after
      insufflation (t2, t3) while the patient was in the lateral semi-oblique position, and again
      10 minutes after desufflation (t4) while the patient was in the supine position. Patient
      demographic data, duration of anesthesia, duration of surgery, lateral position time,
      pneumoperitoneum time, and recovery time were also recorded. used in both groups. Bilateral
      rSO2 values were recorded at baseline, at 1 minute after induction, and then every 5 minutes
      until the patient went to the recovery unit. Data for mean arterial pressure (MAP), peak
      heart rate (HR), SpO2, and ETCO2 were also recorded at the same time intervals. Arterial
      blood gas was analyzed in the 5th minute after induction (t1) while the patient was in the
      supine position, in the 5th and 30th minutes after insufflation (t2, t3) while the patient
      was in the lateral semi-oblique position, and again 10 minutes after desufflation (t4) while
      the patient was in the supine position. Patient demographic data, duration of anesthesia,
      duration of surgery, lateral position time, pneumoperitoneum time, and recovery time were
      also recorded.
    

Detailed description: 
      A total of 62 American Society of Anesthesiologists (ASA) PS class I-III patients between the
      ages of 18 and 65 years who were scheduled for elective laparoscopic nephrectomy (simple,
      partial, or radical) were included in the study.

      A standard anesthesia protocol was used in both groups. Patients did not receive any sedative
      premedication. Upon entering the operating room, they underwent electrocardiogram,
      non-invasive blood pressure, peripheral oxygen saturation (SpO2), rSO2 (INVOS TM 5100C
      oximeter; Covidien), and neuromuscular monitoring (TOF-WatchTM SX; Organon, Dublin, Ireland).
      Subsequently, anesthesia was induced with propofol (1.5-2.5 mg/kg) and remifentanil (1 mcg/kg
      IV bolus for 30-60 seconds, then 0.25 mcg/kg/min), and rocuronium (1.2 mg/kg). Anesthesia was
      maintained with O2/Air (fraction of inspired oxygen of 0.40; inspiratory fresh gas flow of 2
      L/min), sevoflurane (1 minimum alveolar concentration), and remifentanil IV infusion
      (0.1-0.25 mcg/kg/min). Radial arterial cannulation was also applied for arterial blood gas
      analysis and continuous blood pressure measurement. A mechanical ventilator (Draeger FabiusTM
      Plus anesthesia Workstation, Draeger Medical, Lübeck, Germany) was used at settings of tidal
      volume 7-8 mL/kg, inspirium/exprium expiratory ratio 1:2, and positive end-expiratory
      pressure of 5 cmH2O. With these settings, pre-insufflation Sp02 values were maintained at
      >96%, while the respiratory rate was determined with end-tidal CO2 (ETCO2) of 32-37 mmHg.
      These ventilator settings were maintained throughout the operation.

      CO2 insufflation was performed using the closed Veress needle technique with electronic
      laparoflators in the patients who were placed in lateral semi-oblique (60°) and some flexion
      (jackknife) positions before the surgery was started. Intra-abdominal pressure was maintained
      at 8 mmHg in Group LS and at 14 mmHg in Group SP throughout the surgery.

      During the operation, a neuromuscular blockade was achieved with rocuronium infusion (0.3-0.4
      mg/kg/hour) with a post-tetanic count of zero. At the end of the case, extubation was
      provided by decurarizing the rocuronium with a combination of 0.02mg/kg atropine and 0.04
      mg/kg neostigmine. All patients were followed up with nasopharyngeal temperature monitoring
      and were actively warmed using a forced-air warming system to ensure normothermia throughout
      the surgery. Patients were followed up in the recovery unit at the end of the surgery until
      their modified Aldrete score reached ≤9.

      Hemodynamics The data of mean arterial pressure (MAP), peak heart rate (HR), SpO2, and ETCO2
      were recorded at baseline, at 1 minute after induction, and then every 5 minutes until the
      patient went to the recovery unit. MAP and HR values were kept at ±20% of preoperative values
      by changing the remifentanil infusion rate. Hypotension MAP was defined as <60 mmHg and
      bradycardia HR as 45 beats/minute, and these were treated with noradrenaline 4-8 mcg,
      atropine 0.5 mg. Patients who required noradrenaline or atropine more than twice were
      excluded from the study.
    

Intervention name(s): Standart pressure pneumoperitoneum; Low pressure pneumoperitoneum
Intervention type(s): Procedure; Procedure
Intervention description(s): CO2 insufflation pressure was kept at 14 mmHg throughout the surgery.; CO2 insufflation pressure was kept at 8 mmHg throughout the surgery.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The patients were randomly classified into 2 groups. The patients given the low-pressure pneumoperitoneum (8 mmHg) treatment were called Group LP (n = 30), and the patients given the standard pressure treatment (14 mmHg) were called Group SP (n = 30). Each patient and the anesthesiologist responsible for that patient's anesthesia management were blinded to the group assignments.
Masking: Double (Participant, Care Provider)
Primary purpose: Supportive Care
Keywords: Pneumoperitoneum; Spectroscopy; Near-infrared; Oximetry; Brain; Nephrectomy; Surgery; Laparoscopic