Protective Ventilation in Neurosurgery, a Pilot Study
Condition: Nervous System Neoplasms
MeSH terms: Nervous System Neoplasms
Study type: Interventional

Summary: 
      The purpose of this study is to assess the effect size and variability of dural tension
      measured as intracranial pressure (ICP) below the dura of the surgical field in patients
      undergoing elective supra-tentorial surgery for brain neoplasms in patients alternatively
      ventilated with traditional high-volume-no-PEEP ventilation and protective
      low-volume-low-PEEP ventilation.
    

Detailed description: 
      The role of mechanical ventilation in patients undergoing general anesthesia is worldwide
      well known but it has been associated with dangerous effects such as pulmonary complications,
      increasing postoperative morbidity and mortality. Lung-protective ventilation using low tidal
      volume and positive end-expiratory pressure (PEEP), can reduce morbidity and mortality in
      patients with acute respiratory distress syndrome and is now considered a strong
      recommendation in patients undergoing general anesthesia. At the moment there are no
      guidelines that define which kind of ventilation should be used.

      Patients without acute lung injury are still ventilated with large -and perhaps too large-
      tidal volumes. A recent multicenter randomized controlled trial has concluded that the use of
      a lung-protective ventilation strategy in intermediate-risk and high-risk patients undergoing
      major abdominal surgery was associated with improved clinical outcomes and reduced health
      care utilization . A multicentre randomized controlled trial on mechanical ventilation during
      general anesthesia for open abdominal surgery has concluded that an intraoperative protective
      ventilation strategy should include a low tidal volume and low PEEP, without recruitment
      maneuvers. In 52 patients undergoing general anesthesia for open thoracic surgery lung
      protective ventilation was associated with better intraoperative and postoperative
      oxygenation, and shorter duration of postoperative mechanical ventilation from ICU admission
      to its withdrawal.

      In conclusion protective ventilation, with low tidal volumes and low PEEP, seems to be the
      gold standard for intra-operative mechanical ventilation during general anesthesia.

      Mechanical ventilation represents an important tool to obtain cerebral de-bulking during
      neurosurgery by maintaining moderate hypocapnia and positive intra-thoracic pressure the
      lowest possible. For these reasons the application of PEEP with high tidal volume has been
      historically seen as unfavourable by neuro-anesthesiologists and neurosurgeons fearing
      transmission to intracranial compartment of high venous pressure values with consequent brain
      swelling and eventually cerebral perfusion pressure reduction.

      Nevertheless, recent studies suggested that in patients with traumatic brain injury (TBI)
      PEEP seems to be well tolerated without deleterious intracranial effect and its role in the
      context of a protective ventilation protocol associated with low tidal volume, so with low
      expected intra-thoracic pressures, has never been studied in patients undergoing to general
      anesthesia for intracranial surgery of neoplasms.

      The traditional high-volume-no-PEEP ventilation strategy, called this way because it consists
      of an higher tidal volumes than protective ventilation and no PEEP, in neurosurgery should be
      compared with the recently proposed protective ventilation in order to eventually assess
      possible differences on respiratory and neurological outcomes. At this purpose a pilot study
      is needed to determine the effect size and variability of possible differences in dural
      tension between the two ventilation strategies.

      Null hypothesis: Shifting from traditional ventilation protocol to a protective one during
      general anesthesia does not change levels of dural tension in patients undergone to elective
      neurosurgery for brain neoplasms.

      To determine the effect size and variability of dural tension differences in patients
      undergoing intracranial neurosurgery and ventilated with either traditional or protective
      ventilation.

      Mono-centric, double blind, 1:1 randomized, 2x2 crossover clinical trial. Patients will be
      randomized to receive either traditional or protective ventilation as the first ventilation.
      Randomization will be performed by a computer generated sequence. The results of the
      randomization will be transferred in sealed envelopes, one for each patient. When the patient
      will be randomized in the study, the envelop will be open and the piece of information about
      the randomization present in the envelop will be followed by the operating room
      anesthesiologist.
    

Intervention name(s): Traditional to protective ventilation; Protective to traditional ventilation
Intervention type(s): Procedure; Procedure
Intervention description(s): Traditional ventilation will be set with 9 ml/kg with predicted body weight of tidal volumes and no PEEP and switched to protective ventilation after intracranial pressure measurement.; Protective ventilation will be set with 7 ml/kg tidal volume, 5 cm H2O PEEP, and 0.4 inspired O2 fraction (FiO2), and switched to traditional ventilation after intracranial pressure measurement.
Other intervention name(s): Traditional to protective
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Prevention