HBOT Safety/Review Questions #8
You receive by referral a middle aged F/S Schnauzer with severe pancreatitis.
The patient's primary care veterinarian has specifically directed the client to your hospital for adjuvant HBOT along with traditional supportive treatment. The owner writes in the "previous illness" area of the admitting information form that this patient had a pacemaker implanted 2 years ago to treat "sick sinus syndrome." Is this patient a candidate for HBOT? Please discuss your response.
ANSWER: In terms of the pacemaker itself, there should be no concerns with HBOT and pressure issues. Pacemakers produced after the 1960's are routinely tested at pressure (Reference Kindwall and Whelan, Hyperbaric Medical Practice, Second Edition, Best, 2004, page 88). Consultation with the manufacturer on this testing can be obtained to reassure an owner. It is advisable to take a current thoracic radiograph to rule out occult pneumomediastimum / pneumothorax in these patients prior to HBOT.
You are treating a canine patient for sepsis with adjuvant HBOT.
The technician supervising the session notes that the acrylic window (or porthole in the case of a metal chamber) is fogging heavily during the session. Please discuss the potential cause(s), and how to proceed.
ANSWER: Excessive fogging of the acrylic tube, treatment module, or porthole may signal that the oxygen flow rate of the chamber is too low, or that the patient is overheated. Close attention to the patient's respiratory rate and demeanor is indicated. Check the oxygen sensor to assure that the oxygen percentage in the chamber is in the mid to high 90's. Increase the flow rate of the chamber and see if that will reduce or clear the fogging. If there is any suggestion that the patient is uncomfortable or the respirations are inappropriately increased, start an early, normal decompression at a high flow rate and notify the attending doctor. Take the rectal temperature of the patient immediately upon exit from the chamber and report this to the doctor. Have the oxygen delivery system and "in-line" filters inspected.
If a seizure is observed while a patient is in the chamber it is advisable to reduce treatment pressure AFTER the major motor activity ends, and to notify the attending doctor.
Please explain another option if your chamber has an alternative supply of "medical breathing air."
ANSWER: If your chamber has a supply of "medical breathing air" (in addition to oxygen), you may switch over to this supply immediately if a seizure occurs during an HBOT session, WITHOUT reducing the treatment pressure. The effect will be to reduce the percentage of oxygen in the chamber, and thus in the brain of the patient being treated, without immediately reducing the chamber pressure. This can be done as soon as a seizure is recognized by opening the supply of medical breathing air (images below) and closing the supply of 100% oxygen. The attending doctor should be immediately consulted as to the plan for the remainder of the treatment session. After the seizure ends it is possible to continue the treatment session at a lower pressure and resume the 100% oxygen supply, or to gradually and normally terminate the treatment session using medical breathing air or 100% oxygen.
Which of the following should be performed on a daily basis on your hyperbaric chamber?
Clean the hair and dander from the bottom of the chamber.
Calibrate the oxygen monitor.
Check the connections on all grounding plates.
Clean all treatment modules and the chamber itself with a soapy water solution and dry with a 100% cotton towel.
All of the above.
ANSWER: 5. All of the above
The chamber must be clean and free of all sources of combustible materials like hair and dander, which tend to accumulate on the bottom, below the gurney or tray (image). The grounding accessories are necessary to inhibit static electricity development and discharge, and the oxygen monitor assures effective and safe therapy.
You are about to place a gastric feeding tube in a cat with severe thermal burns.
You plan to treat this cat with adjuvant HBOT to speed healing of its wounds and assist in pain management. Which type stomach tube should you NOT select to use if the patient will be treated with HBOT, and why?
ANSWER: You can add another layer of 100% cotton stockinette over the tube. This will effectively cover the polyethylene or silicon tube with a layer of cotton (see image below). Remember, the rule of thumb: Anything other than the patient itself shall be covered with 100% cotton. The adjuvant HBOT modulates the genetic inflammatory response, shifting it toward the anti-inflammatory expression. This is especially useful in clinical processes such as "Triaditis". Measurements of human tissue cultures in vitro demonstrate changes in MRNA levels of inflammatory genes after HBOT (Reference, Kendall et al, UHM 2013, Volume 40, number 2, GPS. 115-123, Different oxygen treatment pressures alter inflammatory gene expression in human endothelial cells).
You have two patients in separate modules during an HBOT session.
Which circumstance below is an absolute indication for beginning a normal, gradual, but premature conclusion to the treatment session?
One patient, a cat, pulls off the ground wire connection on the grounding plate in his module and continues to chew on the wire without stopping.
One patient urinates in the module.
One patient defecates in the module.
One patient vomits in the module.
None of the above.
ANSWER: 1. One patient, a cat, pulls off the ground wire connection on the grounding plate in his module and continues to chew on the wire without stopping.
A gradual decompression should be started if a patient begins to act in a manner which may cause self harm or injury. In this case, we do not want the cat to swallow a piece or pieces of the wire and create a GI foreign body, or injure his mouth on the wire. The other answer options are not absolute indications for premature termination of a treatment session, and can usually be cleaned up after the session.
You are treating a canine with complete global ischemia secondary to cardiopulmonary arrest.
He is known to be a well-controlled idiopathic epileptic. His body temperature is below normal. Will the low body temperature increase or decrease the chance for CNS oxygen toxicity and seizures during an HBOT session?
ANSWER: A patient with a low body temperature will have a reduced chance for oxygen toxicity and thus oxygen induced seizures (Reference Kindwall and Whelan, Hyperbaric Medicine Practice, Second Edition Revised, Best, 2004, page 76). Conversely, elevated body temperature increases the possibility of oxygen toxicity.