Practical critical care techniques (Proceedings)
Emergency and critical care medicine is one of the fastest growing fields within veterinary medicine. The standards and quality of care continue to rise and the pet owning community is expecting state of the art care for their pets. This driving force has led to 24 hour care centers and emergency care centers providing excellent patient care all over the USA and Canada. Many of these facilities are performing advanced diagnostic and therapeutic techniques and not simply acting as triage and stabilization units.
Until recently, many procedures that should and could be performed on critically ill patients were not included in the core curriculum at most veterinary schools. With this in mind, the following presentation will review some basic procedures that may aid in management of the critically ill patient.
Nasal oxygen supplementationNasal oxygen supplementation is a safe and effective technique for providing oxygen supplementation for the critically ill patient. There are numerous clinical indications for oxygen therapy and variable techniques to provide oxygen support. If there is doubt whether a patient requires oxygen, a therapeutic trial is suggested. The advantages of nasal oxygen supplementation include; ease of administration, ease of patient monitoring, non-invasive technique and no special equipment requirements. The disadvantages of this technique include; lack of patient tolerance, epistaxis, aerophagia and the inability to know the exact fraction of inspired oxygen.
The technique is quite simple and requires minimal equipment. Any type of flexible tube sizes 3.5-8.0 F can be used. Urinary catheters and pediatric feeding tubes work well. The nasal mucosa should be desensitized with topical anesthetic (lidocaine or proparacaine), which should be allowed to take effect over several minutes. The anatomic landmarks utilized are the external naris and the vertical ramus of the mandible. The tube is passed into the ventral nasal meatus to the vertical mandibular ramus. The tube can be attached via cyanoacrylate (super glue) and or sutures to the external naris and the muzzle over the frontal sinus. An E-collar may be used for patients that will not tolerate this technique to prevent dislodgement. If used for extended periods of time, the oxygen should be humidified.
The use of an intraosseous or intramedullary catheter is valuable in the critically ill animal when venous access is not available. Fluid therapy as well as emergency drugs can be administered via this route. There are several anatomical sites that can be utilized. These sites include the greater tubercle of the humerus , the trochanteric fossa of the femur, as well as the medial aspect of the proximal tibia. Purpose made intraosseous catheters are available or any standard bone marrow needle can be used. In young animals hypodermic or styletted spinal needles may be used. In most cases these catheters can be placed with light sedation and infiltration with local anesthesia. The area where the catheter is to be placed is shaved and aseptically prepared. The region should be infiltrated with lidocaine making sure to infiltrate the periosteum. A small stab incision is made in the skin with a scalpel and the bone marrow needle is driven into the bone using a screw like motion. The size of the needle can vary depending on the size of the patient. Usually 16-18 gauge needles work best. To avoid a cortical bone plug it is important to keep the stylet in place if using a styletted needle. Once placed, aspiration can be performed to check placement and saline can be infused. This area can be covered with 4" x 4" gauze with antiseptic or antibiotic ointment and bandaged.
Recently a new technique has been introduced for rapid introsseous catheter placement. The EZ-IO® infusion system uses a slow speed, hand held, battery operated drill that places a purpose made bone marrow catheter.