Ventilator Setup and Troubleshooting Guide

Ventilator Management Summary

Initial Assessment

Begin with manual ventilation
Assess chest compliance
Check for respiratory obstruction

Initial Settings

FiO₂: 1.0 initially
Vt: 6-8 mL/kg (500 mL adult)
RR: 12-15 breaths/min
PEEP: 5 cmH₂O
I:E ratio: 1:2

Monitoring

Check ABG at initiation
Repeat ABG after 20 minutes
Adjust settings based on results

Troubleshooting (POPES)

P: Position of tube
O: Obstruction
P: Patient issues
E: Equipment failure
S: Splinting issues

Emergency Response

Switch to hand ventilation
Systematically check equipment
Assess patient condition

Basic Principles

Initially the patient's lungs are ventilated manually, which enables an assessment of chest compliance and assists in the detection of any respiratory obstruction.

If possible, the patient's lungs are then ventilated with a portable ventilator; this gives constant ventilatory support and helps achieve a steady state
Check arterial blood gases when mechanical ventilation is commenced and 20 minutes later to guide adjustment of ventilator settings
Patients with very stiff lungs (e.g. pulmonary oedema or severe asthma) may need hand ventilation until a ventilator of higher specification is available
In some modes of ventilation, the ventilator does not interact with a patient's efforts to breathe (continuous mandatory ventilation, CMV), whilst in others it detects and interacts with those efforts (synchronised intermittent mandatory ventilation, SIMV)
SIMV is useful if neuromuscular blocking drugs haven't been given, if the patient has recovered from neuromuscular blockade, or if weaning and assessing the presence of respiratory effort; where a patient does not initiate breaths, the set SIMV breath rate is delivered in the same way as CMV (giving a backup minute volume)
Regular suction of secretions is also important
Use of positive end expiratory pressure (PEEP) is recommended in most patients; this will improve oxygenation and decrease the FiO2 required, primarily through recruitment of alveoli (in the hypotensive patient, use of high PEEP values will increase intrathoracic pressure and reduced venous return to the heart which may exacerbate hypotension)

Initial Ventilator Settings

Pre-connection Check

Before attaching to the patient, perform a quick ventilator check to ensure proper functioning and prevent complications.

Connect O2 supply via a Schrader valve to the wall supply or cylinder and turn the ventilator on.

For a 'standard' adult set FiO2 to 1.0.

Set the mode to intermittent positive pressure ventilation (IPPV).

Set a tidal volume (VT) of 6 - 8 mL/kg (500 mL for a 'standard' adult) and an appropriate respiratory rate (RR) to achieve a minute volume (MV) of 100 mL/kg (15 breaths/minute for a 'standard' adult).

Set the peak airway pressure (Pmax) to 40 cmH2O.

Set the positive end expiratory pressure (PEEP) to 5 cmH2O.

Set inspiratory:expiratory (I:E) ratio to 1:2.

Connect to a test 'lung' (or use the reservoir bag of an anaesthetic breathing system).

Check that the 'lung' inflates and deflates.

Squeeze the 'lung' to simulate obstruction or increasing airway pressures and check that the P极ax alarm sounds.

Disconnect the circuit and check that the disconnect alarm sounds.

Connect to the patient.

Adjust VT according to clinical chest expansion and peak airway pressures (< 20 cmH2O with normal lungs).

Ventilator Troubleshooting

Immediate Action

It is safest to switch to hand ventilation whilst solving a ventilation problem. If you can adequately hand ventilate the patient then systematically check for ventilatory or circuit issues.

POPES Mnemonic for Ventilation Failure

P: Position of tube

Oesophageal or bronchial intubation
Tube out of trachea
Tube displacement

O: Obstruction

Tubing obstruction
Tracheal/bronchial obstruction
Bronchoconstriction
Secretions blocking airway

P: Patient

Pneumothorax

Pulmonary embolism
Pulmonary oedema

Atelectasis

Bronchospasm

E: Equipment

Incorrect kit
Connection/equipment failure
Inadequate gas flow
Power failure
Leaks in the system

S: Splinting

Abdominal distension including stomach distension
Poor paralysis
Patient-ventilator asynchrony
Inadequate sedation

Common Problems and Solutions

Problem	Solution
Not ventilating: no noise or pressure generated	Check on/off switch Check O2 source/connections Check power supply
Not ventilating: noise but no pressure generated	Check for disconnections Check ventilation valve Check for tracheal cuff leak Check circuit integrity极li>
Not ventilating: noise and pressure generated	Check for tubing kinks or obstruction Patient may be fighting the ventilator May have stiff lungs Possible tension pneumothorax
Hypoxaemia	Check clinical air entry Increase FiO2 Increase PEEP Consider tracheal suction Check tube position
Hypercapnoea	Increase MV by increasing RR Increase tidal volume if possible Check for increased dead space
Hypocapnoea	Decrease MV by decreasing RR Decrease tidal volume if appropriate Consider patient's metabolic needs

Other Considerations

Tube Position Verification

Obtain chest x-ray to check position of tracheal and nasogastric tubes. Clinical assessment alone is not sufficient to confirm proper placement.

Gastric Decompression

Insertion of a nasogastric or orogastric tube into the stomach enables deflation of a dilated stomach and removal of stomach contents; this helps to reduce the potential for aspiration and may sometimes enable lower ventilation pressures.

Chest Drain Consideration

Consider prophylactic chest drains in chest trauma, particularly if the patient is about to be transported or undergo a lengthy procedure where the chest will not be immediately accessible.

Ongoing Management

Continuous monitoring of ventilator parameters, patient response, and regular arterial blood gas analysis is essential for optimal ventilator management. Adjust settings based on clinical response and laboratory results.