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Veterinarian Technician June 2013 (Vol 34, No 6)

Case Report: A Pug With Dyspnea: Stuck Between a Rock and a Hard Place

by Erica Mattox, CVT, VTS (ECC)

    Eleanor—a 19-lb, 11-month-old, spayed pug—presented to the emergency hospital in the evening, with the owners stating that she had been choking on something. Eleanor seemed to be doing better but was still breathing noisily. Radiographs of her thorax and abdomen were obtained, revealing clear lung fields and a mineral-density foreign body (consistent with a rock) in the stomach. An oral examination revealed no foreign body but some irritation. The owners said that Eleanor and a canine housemate ate rocks and sometimes produced stools consisting of nothing but rocks. Because the rocks had always passed, the owners were not concerned about the gastric foreign body and opted to take Eleanor home.

    Physical Examination

    Later the same night, Eleanor returned to the emergency hospital. On my emergency assessment examination, I recognized that Eleanor was alert and responsive but was in severe respiratory distress. The owners stated that Eleanor had fainted several times at home and seemed to stop breathing after the fainting episodes. The owners gave Eleanor a small amount of Benadryl out of concern that she may have been stung by a bee. I immediately took Eleanor to the treatment area and gave her supplemental flow-by oxygen. On examination, Eleanor had a heart rate of 180 bpm (normal: 70 to 120 bpm) and a respiratory rate of 100 breaths/min (normal: 18 to 34 breaths/min), with sudden coughing and pauses in respiration. During auscultation, I noted that her lungs sounded clear but her upper airway sounded raspy. Her heart rhythm was normal. Her temperature was 102.5°F (normal: 100.2°F to 102.5°F), and her mucous membranes were cyanotic. When Eleanor coughed, the dyspnea worsened. I placed an 18-gauge intravenous (IV) catheter in the right cephalic vein and obtained more thoracic radiographs, which revealed a mineral-density foreign body in the trachea, caudal to the thoracic inlet. When the original radiographs were obtained, the foreign body was more cranial and therefore not apparent. Because of Eleanor’s history, the foreign body was believed to be a rock. The emergency doctor informed the owner and our surgeon of Eleanor’s diagnosis. I collected blood from the left cephalic vein. The results of a complete blood count were within normal limits. A chemistry panel revealed a blood urea nitrogen level of 38 mg/dL (normal: 10 to 29 mg/dL), a creatinine level of 1.1 mg/dL (normal: 0.6 to 1.6 mg/dL), a total protein level of 5.9 g/dL (normal: 5.5 to 7.5 g/dL), a glucose level of 200 mg/dL (normal: 65 to 120 mg/dL), an alanine aminotransferase level of >1000 IU/L (normal: 10 to 120 IU/L), and an alkaline phosphatase level of 92 IU/L (normal: 0 to 140 IU/L). An increase in the alanine aminotransferase, blood urea nitrogen, and glucose levels without increases in other values likely indicated stress and increased protein catabolism due to increased respiration. Eleanor’s electrolyte levels were within normal limits.

    Transport for Emergency Surgery

    I transported Eleanor in our critical pet ambulance to our other location to meet the surgeon for emergency surgery. I administered flow-by oxygen during the transport. I was concerned about the need to intubate Eleanor if dyspnea caused decompensation. I worried that intubation (1) would move the foreign body farther into the lungs or (2) would not be possible because of the obstruction. I took a stocked crash cart with endotracheal tubes in case emergency measures were needed. Fortunately, Eleanor did well during the transfer to our main hospital.

    Surgical Intervention

    On arrival at the hospital, Eleanor was examined by our board-certified surgeon. I immediately attached Eleanor to a pulse oximeter, a blood pressure (BP) monitor, and an electrocardiograph (ECG) and began monitoring her heart rate, respiratory rate, mucous membranes, and capillary refill time. On careful palpation of her trachea, Eleanor began to cough, experienced increased dyspnea, and began to decompensate. Eleanor’s heart rate increased to ~200 bpm. The pulse oximetry reading dropped to 90% (normal: >98%) on flow-by oxygen and continued to fall. The end-tidal carbon dioxide (ETCO2) level increased to 80 mm Hg (normal: 35 to 45 mm Hg in dogs). Eleanor’s airway was completely blocked. Her body could not receive oxygen or get rid of CO2. Her heart rate was increasing due to anxiety and her heart’s attempts to get more oxygen to tissues. The doctors attempted to externally move the foreign body to allow breathing, but this was unsuccessful. I titrated a small dose of IV propofol and gently placed an endotracheal tube to provide some oxygen support. I was concerned, as was the surgeon, about pushing the foreign body into the lungs, but Eleanor needed oxygen support. I placed the endotracheal tube slightly past the epiglottis, hoping to allow us more time for a tracheostomy. I also started IV Normosol-R (Hospira) at a surgical rate of 95 mL/h. Eleanor was quickly prepared for surgery, and a ventral cervical approach was used. A tracheostomy was immediately performed, allowing Eleanor to breathe easier. Her heart rate remained high at 200 bpm, but her pulse oximetry reading improved to around 97% and her ETCO2 decreased to 50 mm Hg. The endotracheal tube was placed through the tracheostomy site to supply oxygen and gas anesthesia using isoflurane. Radiographs showed that the foreign body had moved into the right bronchus. During transport from surgery to radiology, Eleanor’s pulse oximetry reading dropped and ETCO2 increased.

    Eleanor was prepared for surgery, and a right-lateral, fifth intercostal space thoracotomy was performed. Entry into the chest cavity removes negative pressure, preventing the lungs from inflating on their own. Therefore, I supplied manual positive-pressure ventilation until the ventilator was set up. Then Eleanor’s respirations were maintained using a bellows ventilator. It was not used before entry into the chest cavity because of concern that extensive pressure on the foreign body would further damage the lungs. Thoracic exploration revealed a stone lodged in a bronchiole of the right middle lung lobe. An incision was made in the right bronchus, and an alligator forceps was used to retrieve the stone. I continued to provide anesthesia via the tracheostomy tube and monitored pulse oximetry, the heart rate, and the ETCO2 level, which all quickly returned to normal after the stone was removed. I also continued to monitor BP (normal systolic: 100 to 160 mm Hg) and the ECG reading, which both remained normal. I had been updating the surgeon on Eleanor’s anesthetic state; because Eleanor’s vital signs were normal, I obtained approval to start pain control. We were initially concerned about administering pain medication because some opioids cause respiratory depression. A fentanyl constant-rate infusion (CRI) was started at 3 µg/kg/h.

    With the doctor’s approval, I administered cefoxitin (190 mg IV). The antibiotics would fight a secondary infection due to extraction of a nonsterile foreign body from the thorax. The bronchus was closed with 4-0 polydioxanone in a simple interrupted suture pattern. A 12-French thoracotomy tube was placed to allow postoperative removal of air and fluid from the thoracic cavity. The thorax was lavaged and suctioned. The thorax and cervical region were closed.

    After the thoracotomy, endoscopy was used to try to retrieve the stone from the stomach. I continued to provide gas anesthesia using isoflurane and to monitor the heart rate, respiratory rate, BP, ETCO2 level, pulse oximetry value, and ECG reading. All these parameters had remained stable. Administration of IV fluid (90 mL/h) and the fentanyl CRI were continued. Attempts to remove the gastric foreign body were unsuccessful due to a large amount of ingesta and phlegm. I was concerned about the amount of time Eleanor had been under anesthesia. She was maintaining well, but the risk of hypothermia and hypotension increases with prolonged anesthesia. The surgeon consulted the owners about performing a gastrotomy at this time, but they declined, saying they were sure that the rock would pass.

    Postsurgical Care

    After anesthesia, I noticed that Eleanor was hypothermic (97°F; normal: 100.2°F to 102.5°F), so I used a commercial patient warmer to warm her. Her breathing was comfortable: her lungs sounded clear on auscultation, and respiratory effort was minimal. Her mucous membranes stayed pink. Her pulse oximetry reading remained at 97% off of oxygen. I was concerned about extubation because of Eleanor’s brachycephaly as well as tracheal and lung insults from the invasive procedures. I made sure that she was fully awake and alert before extubation. Surgical recovery went well.

    I observed a small amount of brown debris from both nostrils about an hour after anesthesia. I noted that the pulse oximetry reading had decreased to 95%, and I suspected nasal congestion. I applied warm compresses to Eleanor’s nose and tried to clear the debris. I alerted the doctor and placed Eleanor in an oxygen cage, where her respiratory effort improved. Eleanor rested comfortably the rest of the night. She was maintained on crystalloid fluid (25 mL/h) and fentanyl (3 µg/kg/h CRI) for postoperative pain. She also received famotidine (4 mg IV) to prevent gastric ulcers. To prevent systemic infection, cefoxitin (190 mg IV q8h) was ordered. Eleanor continued to rest well. The incision sites were intact, with no swelling, bruising, or discharge. The chest tube remained patent and intact. Later that night, I drained the chest tube manually, removing 5 mL of fluid, which was normal for initial postoperative drainage. Administration of crystalloid fluid (25 mL/h) continued. Eleanor became more comfortable, so we began weaning her off of the fentanyl CRI by reducing the rate from 3 µg/kg/h to 2 µg/kg/h. Cefoxitin was replaced with enrofloxacin (86 mg IV) and ampicillin (190 mg IV q24h).

    At 2:00 am, I drained the chest tube manually, removing 4 mL of fluid. Early in the morning, Eleanor was interested in food, so with the doctor’s approval, I offered her small amounts, which she immediately regurgitated. She continued to have nasal discharge and occasional coughing but no respiratory distress.

    I alerted the doctor after each regurgitation episode and expressed my concern that the gastric foreign body might be causing obstruction. I was instructed to repeat the abdominal radiography, which showed that the foreign body was still in the stomach. Due to recent surgery and Eleanor’s nonpainful abdomen, the surgeons decided to discontinue feeding and to schedule endoscopy with our internal medicine specialist; if unsuccessful, abdominal exploration was a possibility. We hoped that time had allowed most of the ingesta to pass from the stomach into the small intestine to allow better endoscopic visualization of the foreign body and easier removal.

    The next day, Eleanor was recovering well. She was breathing well but continued to regurgitate. Endoscopic removal of the stone was unsuccessful. A ventral midline celiotomy was performed, and a large stone was palpated in the stomach. A gastrotomy was performed, and the stone was removed without complications. Recovery from anesthesia was uneventful. Eleanor’s chest tube remained patent, with a small amount of fluid aspirated. A few hours after gastrotomy, Eleanor was removed from the oxygen cage and her pulse oximetry reading remained normal (97%) off of oxygen.

    By the evening, Eleanor was doing well. She was not returned to the oxygen cage, and her pulse oximetry reading was 97%. Her vital signs and the ECG and BP readings remained normal. She was alert, comfortable, and interested in food. I started giving her small amounts of food after informing the doctor of her interest. She did not vomit after eating. We began administering morphine (15 mg PO) and Clavamox (Pfizer; 125 mg PO) twice daily. One hour later, we discontinued the fentanyl CRI and the injectable antibiotics. I attempted to manually drain her chest tube but aspirated only about 0.5 mL of blood-tinged fluid, which I reported to the doctor. I removed the chest tube and placed a light bandage around the entry wound per the doctor’s orders. Eleanor remained in the hospital over the next 12 hours, continued to do well, and was released to her owners.

    NEXT: Direct Blood Pressure Monitoring: Simple and Inexpensive

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