Question

A 45-year-old, 6-foot tall man presented to the emergency room with a two day history of fever and cough productive of brown sputum. He was hemodynamically stable at the time with a blood pressure of 130/87. His chest x-ray showed a right middle lobe infiltrate and his room air ABG showed: pH 7.32, PCO₂ 32, PO₂ 78, HCO₃ - 18. He was started on antibiotics and admitted to the floor. Four hours later, the nurse calls because she is concerned that he is doing worse. On your arrival in the room, his blood pressure is 85/60, his pulse is 120 beats/minute and his oxygen saturation, which had been 97% on 2L oxygen by nasal cannula, is now 78% on a nonrebreather mask. The patient is obviously laboring to breathe with use of accessory muscles and is less responsive than he was on admission. He is diaphoretic and cannot talk in full sentences. On lung exam, he has crackles throughout the bilateral lung fields. You obtain a chest x-ray which shows increasing bilateral, diffuse lung opacities. An ABG is done while he is on the non-rebreather mask and shows: pH 7.17, PCO₂ 45, PO₂ 58, HCO₃ - 14.

What should you do now? Is there a role for CPAP or Bi-level positive airway pressure in managing his hypoxemia?

A decision is made to intubate the patient and initiate mechanical ventilation for worsening respiratory failure. The intubation proceeds without difficulty. The tube position is confirmed and the anesthesiologist leaves the room. The respiratory therapist has secured the endotracheal tube. She turns to you and asks what settings you would like to use for the ventilator?

What information do you need to provide to the respiratory therapist?

The respiratory therapist suggests you use the volume-targeted Assist Control (AC) mode of mechanical ventilation. How does this work? How does it differ from Synchronized Intermittent Mandatory Ventilation (SIMV) or Pressure Control (PC)? Which mode is better for your patient?

Suppose you put the patient on a volume-targeted Assist Control mode of mechanical ventilation. How do you choose the tidal volume?

What respiratory rate should you choose for the patient?

What should the FiO₂ and PEEP be set at?

Answer 1

There is no role of CPAP or Bi PAP for this patient.At present i should take the help of Rapid Response Team to intubate the patient and to treat his hypoxemia.There is no role for CPAP and Bi PAP as these are the remedies to support the patient ventillation in sleep apnoea.BiPAP is use for the patient who require the breathing support in inhalation and exhalation.This include various respiratory disorders including sleep apnoea,COPD etc.Here the patient has the respiratory failure.Which cannot be corrected with CPAP or BiPAP

Should provide the ABG value and the chest xray which had taken just before intuvationg the patient.

In volume-targeted Assist Control (AC) mode of ventillation the volume is set already.That means the tidal volume is set already.And the ventillator deliver the same amount of volume during each breath.This is mainly used in patients with acute respiratory failure.The repiratory system of the patient or the machiene cause to deliver the preset tidal volume.To be in detail when the patient or the machiene does not take the ventillation the machiene will sense the trigger threshold which is preset already and it deliver the ventilation.

SIMV is prefered for the patient who takes breath rapidly in assist control mode.In SIMV the sponateous breath of the patient is happening.In assist control mode the volume of delivered by the machiene is constant thet means which is set by the user.But in SIMV the volume of air isdetemined by the patient in terms of spontaneous breath.In this patient takes small volume of air in the initial stage but if the volume is goos for the spontanous breath that means the patient is ready to be weaned out.For a patient withn acute respiratory failure it is better to keep the patient in assisi control mode because the SIMV mide can lead to decrease in the cardiac out put.

In pressue controled mode of ventilation the volume may vary in each breath according to the condition but the pressure is preset one according to the user.

It is better to keep pressure regulated volume control for my patient as the patients xray shows right middle lobe infiltrate and the increasing opacities in bilaterly in the next xray.

The normal tidal volume is the 7ml /kg body weight is set for a patient with normal body weight.If not for lean personality it is kept as 10ml / kg of body weight in assist control mode..Tidal volume means the volume of air the patient inhales when ther is no extra effort is applied.

Arespiratory rate of 15 -18 bpm can be set for this patient as it is the normal breaths per minute for an adult patient.

At the initial stage of intubation the FIO2 can be set at 100% withy PEEP with PEEP at 4 - 5 cm of water.Because the patient has low blood pressure and the use of drugs during intubation could even more bring down the blood pressure.If we keep high peep it can lead to increse in the intrathorasic pressure and the blood pressure will come down.Now in this situation we have kept FIO2 at 100% this will be sufficient to keep maintain the oxygen level.