Clearing the Airway

Rapidly clearing the airway to improve ventilation or facilitate breathing is a critical element of airway management. Suctioning in the prehospital environment involves mechanical aspiration of blood, vomitus and pulmonary secretions from the patient's airway. Safe suctioning requires a core knowledge of equipment, techniques, patient preparation and the complications that may occur during the procedure.

Role of Suction in Airway Management

A patent airway is crucial to patient survival. Removal of accumulated secretions, blood and vomit increases respiratory efficiency, decreases the risk of complete airway obstruction and improves visualization of the trachea for intubation.1

Awareness of the risks involved is the first step toward developing a plan for prehospital suction of the critically ill patient. Together with appropriate use of equipment, this enables provision of the best possible patient care during suctioning.2

Working under local policies and procedures, the EMS provider must determine the most appropriate method for suction, taking into consideration issues of patient safety, time requirements, the suction source and patient comfort. Suctioning is not a benign technique. Providers must also have plans for resolving problems that may occur during suctioning. Tracheal trauma, suctioning-induced hypoxemia, hypertension, cardiac dysrhythmias and raised intracranial pressure have all been associated with suctioning. Several studies also note the need for psychological support for the conscious patient.3

Suction Equipment Check

Today's suction units offer easy-to-use testing to quickly confirm that all functions are in working order: occlusion check, vacuum buildup efficiency, maximum achievable vacuum level and air leakage status. Large dials and single-control units are easier to operate with gloves and in the often-constrained environments of EMS operations. Check all of your unit's suction equipment at the beginning of each shift and after each use, following the manufacturer's recommendations. Portable and wall-mounted suction devices within the ambulance commonly have variable vacuum settings of 0 mmHg-

500 mmHg. Suction pressure in mechanical, battery-operated units and Venturi systems can be regulated with adjustment of a control knob or valve.

Suction systems incorporate some form of check valve to prevent liquid or particulate matter entering the suction line to the pump. Never connect the suction tubing directly to the suction source. Bypassing the trap could result in contamination of the pump and associated tubing, degradation of pump performance or complete pump failure.

Suctioning Equipment

Suction can be delivered pneumatically by oxygen, manually by hand or foot, or through an electric pump powered by the vehicle's power supply or a battery. Increasing the rate of aspiration significantly makes it possible to remove large foreign material from the airway. This suction technique requires large suction tips. Ensure all connections are secure during the vehicle check-out at the beginning of each shift. The tubing must be connected to the proper suction tip for optimal suctioning.

Battery-Driven Suction Devices

Battery-powered suction devices are ideal for emergency and field situations. When properly maintained, the devices deliver consistent and reliable suction for EMS operations. These devices do not require a gas source, manual operation or close proximity to the ambulance. The battery-driven portable suction unit must be small, lightweight, have a high-capacity battery and provide for the easy, safe and rapid removal of any contaminated supplies.

Ambulance-Mounted Suction Units

The ambulance pump servicing the suction system should include a controllable suction regulator, system alarms, if needed, a vacuum gauge and a suction outlet. Particle traps, or some system to collect an overflow of suctioned material, should be placed between the collection reservoir and the suction pump. The trap should be visible to the operator.

Venturi Suction Systems

Venturi suction systems operate using a compressed gas source to produce suction as the gas is released and passes through a small orifice, the Venturi. The compressed gas leaves the Venturi at high speed, drawing with it approximately the same volume of the gas to be scavenged. Negative pressures generated can be adjusted by varying the Venturi flow rate. Should the outlet from the Venturi become obstructed, driving gas will pressurize the system and whatever is connected to it, including the patient if connected directly. All Venturi suction systems should have a positive pressure relief valve.

Venturi systems require large volumes of high-pressure gas. Venturi systems do not require electricity and are beneficial where emergency electrical power is unavailable.

Manually Driven Suction Units

Manually driven suction units are simple, yet efficient for all EMS systems. These units require no batteries, no power connections, and are lightweight and easy to store. Manually operated units typically work with one hand or are driven by a foot-pumping action, allowing the other hand to perform additional patient care tasks and control the suction catheter.

The reusable components of manually driven suction systems are immersible for cleaning and disinfection. Refer to manufacturer's recommendations for proper cleaning process. No vacuum buildup time is required and there are no batteries to service.

Patient Preparation

Suctioning is a component of bronchial hygiene that involves mechanical aspiration of secretions from the nasopharynx, oropharynx and trachea. The airway may be in its natural state or artificial (such as an endotracheal tube). The patient may or may not be receiving mechanical ventilation. The procedure includes patient preparation, the actual suctioning event, and follow-up care and observation of the patient.5

To prepare the conscious patient for suctioning, the patient must be pre-oxygenated with 100% oxygen for at least 30 seconds prior to the suctioning event. Some patients' condition may preclude the use of pre-oxygenation techniques, as the airway may be obstructed, preventing oxygenation. Suctioning of the airway may be indicated to allow for oxygenation.

Pre-oxygenation may be accomplished by use of a temporary oxygen enrichment with a high-flow non-rebreathing mask in the spontaneously breathing patient, a mechanical ventilator, manual ventilation with a bag-valve-mask and a FiO2 of 100. In preparation for the suctioning event, the patient may be hyperventilated by delivery of an increased rate and/or tidal volume. Provide for an adequate expiratory time to allow for complete exhalation of the delivered tidal volume. Place the patient on a pulse oximeter to assess oxygenation during and following the procedure.

Positioning the patient properly for ventilation, airway management and suctioning can assist the EMS provider in avoiding unnecessary intubation. The conscious patient will resist lying supine while in need of suctioning or at any time in respiratory distress. Position the patient on his/her side while providing access to the airway and controlling patient movement on the cot. Patients can also be left in an upright position for suctioning.

The conscious patient, especially one with a chronic problem, may recognize the need for suctioning and be capable of self-suctioning. Allow the patient to use the suction catheter to clear his or her own airway. This will assist in avoiding painful stimulation of airway tissues.

Many patients with artificial airways, like tracheostomy tubes, require effective suctioning. Calls to EMS may be initiated due to problems related to suctioning in the home- care patient. The patient's cannula may be clogged with mucus or other dried material, making suctioning difficult. Communicate with the conscious patient the need for suctioning and the mechanics of the procedure. These patients are often comfortable with the suctioning procedure but require assistance due to a problem.

Sterile technique should be employed during placement of a suction catheter through the endotracheal tube into the trachea and application of negative pressure as the catheter is being withdrawn. Each pass of the suction catheter into the artificial airway is considered a suctioning event. The duration of each suctioning event should be approximately 10 seconds. Suction pressure should be set as low as possible to still effectively clear secretions. Experimental data to support an appropriate maximum suction level are lacking. Some textbooks cite maximum safe limits of 100-150 mmHg but do not reference their recommendations.6

Monitoring During Suctioning

The patient requiring suctioning of the airway is often critically ill or injured and will require intensive monitoring and assessment.

• EKG: The EKG monitors the patient for dysrhythmias, ischemia and rate changes due to suctioning.
• An automated noninvasive blood pressure measurement system can be invaluable during suctioning. The patient's hemodynamics can change significantly during suctioning and management of a difficult airway. The monitor can provide frequent and repeated blood pressure measurements, even in a high noise environment.
• Pulse oximetry: An invaluable monitor for all EMS situations, the pulse oximeter is used nearly universally in critically ill patients. The patient requiring urgent suction may be at significant risk for hypoxia. In addition to monitoring the concentration of saturated hemoglobin, a pulse oximeter also provides clinical data on pulse rate and peripheral perfusion.
• Capnography: The end-tidal CO2 monitor provides prehospital clinicians information on the adequacy of ventilation following suctioning. Ventilation and gas exchange should improve following suctioning.
• Defibrillator: Combined with all of the above monitoring parameters, a defibrillator should be immediately available.

Results and observations related to suctioning should be documented to inform and alert other prehospital clinicians and upon arrival at the hospital.

Infection Control

All prehospital clinicians should practice infection control procedures appropriate to the EMS environment. To the extent feasible, patients should be protected from active viral and bacterial infections that are airborne or spread by direct contact. Standard PPE precautions must be used in each instance of suctioning.

Clean, disinfect and replace all suction equipment and supplies, beginning with thorough mechanical cleaning of the suction device with an approved detergent and water approved by your local policies and procedures. The use of single-patient supplies eliminates the need for extensive cleaning and sterilization of equipment after each patient. Suction catheter wrappers that are damaged or soiled during storage may be contaminated.

Suction-Related Problems

The most common problem related to suction is not having it available when you need it on scene.7 Suction should always accompany EMS providers to the patient's side. Suction must be immediately available and working for any rapid sequence intubation, difficult airway, trauma or other situation involving airway management.

Other suction issues include:

• Catheter problems, including post-resuscitation infection, mechanical trauma to teeth or mucosa, breakage of rigid flexible catheters, airway disconnection during suction, hypoxia and patient discomfort.
• Excessive suction, producing hypoxia and subsequent tachycardia with an increase in myocardial oxygen demand. Properly administered suctioning will avoid the potential for hypoxia.
• Infectious hazard to individuals cleaning suction apparatus, filters and traps.

Post-Suction Care

Following the suctioning event, the patient should be monitored for adverse reactions such as hypoxia, coughing, increased airway pressure (difficult to ventilate using the same technique), tachycardia or patient discomfort. The patient in whom pre-procedure hyperventilation was indicated should be treated by the same method(s) post-procedure.

Contraindications to Suctioning

Most contraindications are relative to the patient's risk of developing adverse reactions or worsening clinical condition as a result of the procedure. When indicated, there is no absolute contraindication to endotracheal suctioning. Abstaining from suctioning in order to avoid a possible adverse reaction may, in fact, be lethal.

Dislodgement and introduction of bacteria into the lower airway through the tracheal tube have been demonstrated. Trauma to the airways is also possible. In general, however, deterioration in respiratory, cardiovascular and other physiological systems are potential complications of any suctioning procedure. Examples of these adverse events during suctioning include plugged or dislodged endotracheal tubes, loss of ventilation, hypoxia and patient discomfort. Pediatric patients are particularly prone to preventable complications during suctioning. The risks to pediatric patients during suctioning include airway trauma, hypoxemia and migration of the endotracheal tube.

Time Limitations of Suctioning

Endotracheal suctioning is not a benign procedure, and the EMS provider should remain sensitive to possible complications, taking all necessary precautions to ensure patient safety. Secretions in the peripheral or distal airways cannot be removed by suctioning, even at high negative pressures for prolonged periods. Doubling the duration of the suction period could also double the decrease in SpO2 levels. The incidence of tracheal lesions found has been directly related to several factors, including the length of time the vacuum was applied during suctioning. Expert opinion suggests that suction duration times of less than 10-15 seconds decrease the risk of trauma, hypoxia and other side effects.

The effectiveness of any pre-oxygenation technique can be influenced by individual patient condition, duration of suctioning, negative suction pressure, suction flow and size ratio between the suction catheter diameter and the diameter of airway lumen. Combining hyperventilation and limiting the duration of suction has been identified as a technique for potentially minimizing suctioning-induced hypoxemia.8

Conclusion

Suctioning has no absolute contraindications in the patient requiring airway clearance. Hyperventilation prior to suctioning, if indicated, can potentially minimize suctioning-induced hypoxemia. Monitor the patient for hypoxemia during the procedure. Secure the endotracheal tube in place and occlude the catheter for 10 seconds. Avoid oversuctioning to decrease potential damage to the patient's airway.

References

1. Doran JV, Tortella BJ, Drivet WJ, Lavery RF. Factors influencing successful intubation in the prehospital setting. Prehosp Disas Med 10(4):259-264, Oct-Dec 1995.
2. Vandenberg JT, Vinson DR. The inadequacies of contemporary oropharyngeal suction. Am J Emerg Med 17(6):611-613, Oct 1999.
3. van de Leur JP, Zwaveling JH, Loef BG, van der Schans CP. Patient recollection of airway suctioning in the ICU: Routine versus a minimally invasive procedure. Intensive Care Med 29(3):433-436, Mar 2003. Epub 2003 Feb 08.
4. Sole ML, Poalillo FE, Byers JF, Ludy JE. Bacterial growth in secretions and on suctioning equipment of orally intubated patients: A pilot study. Am J Crit Care 11(2):141-149, Mar 2002.
5. Day T, Farnell S, Wilson-Barnett J. Suctioning: A review of current research recommendations. Intensive Crit Care Nurs 18(2):79-89, Apr 2002.
6. Sole ML, Byers JF, Ludy JE, et al. A multisite survey of suctioning techniques and airway management practices. Am J Crit Care 12(3):220-230, May 2003; quiz 231-232.
7. Kozak RJ, Ginther BE, Bean WS. Difficulties with portable suction equipment used for prehospital advanced airway procedures. Prehosp Emerg Care 1(2):91-95, Apr-Jun 1997.
8. Maggiore SM, Lellouche F, Pigeot J, et al. Prevention of endotracheal suctioning-induced alveolar derecruitment in acute lung injury. Am J Respir Crit Care Med 1;167(9):1215-1224, May 2003. Epub 2003 Feb 13.