Incidence of Postoperative Delirium in Cancer Patients After Laparoscopic Surgery in Trendelenburg Position

Patients will be allocated sequentially in 2 groups. Sequential allocation will be used in order to control age as a possible confounding factor for the outcome of interest.

These patients will be monitored intraoperatively with electrocardiogram (ECG), noninvasive pressure, pulse oximetry, capnography, BIS, monitor of neuromuscular blocker (TOF), esophageal temperature and Trendelenburg angle.

The measured moments will be patient entry in the operating room, after pre-anesthetic medication, anesthetic pre-induction, after anesthetic induction, after surgical incision, after pneumoperitoneum infusion, after Trendelenburg position, every 15 minutes until the end of the procedure and after extubation.

All patients will receive morphine 50 mcg via the spinal route. All patients will receive intravenous pre-anesthetic medication midazolam 0.03 mg / kg for comfort during spinal anesthesia and 500 ml of crystalloid solution prior to blockade associated with 4 ml / kg / hour of crystalloid solution plus volume to be depended of clinical parameters.

Subarachnoid block will be performed in the seated position, antisepsis / asepsis with alcoholic chlorhexidine, location of the L3 / L4 space, needle puncture with whitacre 27 G, barbotation of 0.5 ml and injection lasting 5 to 7 seconds.

Spinal morphine will be performed with the same anesthetic technique described in the subarachnoid block.

A general anesthetic with pre-oxygenation 8 liters / minute for 5 minutes + fentanyl 3 mcg / kg + propofol 2 mg / kg + rocuronium 0.6 mg / kg will be performed. Patients will be ventilated with a mixture of oxygen and air through an inspired fraction of 40% oxygen and maintaining an expired concentration of carbon dioxide between 35 and 45 mmHg. Anesthesia will be maintained with remifentanil (ng / ml) through Minto's pharmacokinetic model (BBraun infusion syringe - Perfusor® Space model) and desflurane (Fe%).

Hypnosis will be guided by maintaining BIS between 40 and 60 and the dose of remifentanil will be adjusted by vital signs.

Patients with medium arterial pressure with values lower than 60 mmHg will be medicated with vasopressors depending on heart rate. If heart rate is greater than 60 beats per minute (bpm) metaraminol 0.5 mg will be used and 5 mg ephedrine will be used if heart rate less than 60 bpm.

In both groups, the patients will be kept warm with a thermal blanket and will have their esophageal temperature measured (40 cm from the incisor teeth).

After the surgical procedure, neuromuscular blockade will be antagonized with suggamadex, according to the monitoring of neuromuscular blockade through TOF.

- Deep block (at least 1 to 2 responses in PTC, but prior to the appearance of T2, ie the second response to TOF): 4 mg / kg.

- Moderate block (after onset of T2): 2mg / kg.

- 16 mg / kg is recommended if there is a clinical condition requiring rapid reversal (approximately 3 minutes) following the single dose of rocuronium at 1.2 mg / kg.

After 5 minutes of extubation, vital signs (blood pressure, heart rate, saturation) will be collected and the patient will be evaluated for the presence of delirium. Dipyrone 2 grams and parecoxib 40 mg will be performed without contraindication for postoperative analgesia.

Patients will then be referred to the anesthetic recovery room, where they will continue to be monitored with ECG, noninvasive pressure and pulse oximeters. They will also be evaluated for pain in the numerical estimate scale (NRS) (0 = no pain, up to 10 = maximum pain), on arrival and every 30 minutes until the time of discharge into the room. Those who present pain with NRS greater than 4 in PACU will be treated with morphine 1 mg every 10 minutes. Those with nausea / vomiting will be given alizapride 50 mg.

Patients will be assessed with regard to the appearance of delirium by means of CAM (Confusion Assemption Method) in association with the Richmond Agitation Sedation Scale (RASS) scale.

CAM is a simple screening method based on the following four questions, with Criteria 1 and 2 plus 3 or 4 being present:

1. Acute onset: Is there evidence of acute change in the patient's underlying mental state?

2. Attention Disorder: Has the patient had difficulty focusing on his or her attention, for example, was easily distracted or had difficulty following what was being said?

3. Disorganized thinking: Was the patient's thinking disorganized or incoherent, with dispersive or irrelevant conversion, unclear or illogical flow of ideas, or unpredictable change of subject?

4. Changes in level of consciousness: Does the patient present altered level of consciousness such as lethargy, torporous, comatose? The RASS, was developed with the purpose of characterizing the level of consciousness and agitation. Signs of hyperactive delirium are defined as scores ranging from +1 (anxious patient), +2 (frequent uncoordinated unintentional movements, fight against ventilation), +3 (aggressive) to +4 (very aggressive). Signs of hypoactive delirium are defined as RASS ranging from - 5 (patient does not respond), - 4 (no response to voice sound), -3 (movements or ocular opening to voice sound), -2 (awakens briefly), - 1 (not completely alert) to 0 (patient calm or sleepy).

This evaluation will be performed by nurses, previously trained, on arrival at PACU every 30 minutes until discharge from the post-anesthetic recovery room and 24 hours after the patient's discharge from the hospital. In cases where the patient has an episode of persistent delirium for more than 1 hour, the evaluation of a psychiatrist will be requested for follow-up and treatment.