Tratamento de tromboembolismo e preparo para implantação de prótese osteointegrada com oxigenioterapia hiperbárica em uma gata / Treatment of tromboembolism and preparation for an osseointegrated prothesis fixation with hyperbaric oxygen therapy in a kitten

Background: Ischemic neuromyopathy is the most common reason for amputation in cats. In veterinary medicine, the use of prosthetic limbs is not widespread; therefore, in most cases total limb amputation is indicated. However, hyperbaric oxygen therapy (HBOT) is an alternative with several benefits for the treatment of vascular disorders with reperfusion, ischemia, and infection. Therefore, this study aimed to report the positive effects of HBOT on the treatment of ischemic neuromyopathy secondary to arterial thromboembolism on the patient's clinical improvement, and on the preparation of the patient for insertion of an osseointegrated prosthesis. Case: A 6-month-old mixed-breed kitten returned for treatment after undergoing surgery seven days earlier for reduction of traumatic diaphragmatic hernia, during which it suffered a cardiorespiratory arrest. The patient presented with acute pelvic limb paralysis with 24-h evolution, absent femoral pulse, plantar cushions and dorsal part of the limbs cold and pale. After supportive therapy and diagnosis of aortic thromboembolism by arterial Doppler, the patient started adjunctive treatment with HBOT from the first day of hospitalization. Sessions took place in an exclusive hyperbaric chamber for animals and lasted 60 min at a pressure of 2.5 absolute atmospheres and 100% oxygen, initially every 12 h. However, during the first 5 days of hospitalization, the distal region of both pelvic limbs began to show tissue devitalization and edema, and hematologic parameters showed changes on the 7th day. The right pelvic limb (RPL) showed more involvement of superficial tissues, extending to the tarsometatarsal joint region. After 8 days of hospitalization, the devitalized tissue was debrided. The RPL had an extensive devitalized area with exposed bone in the phalanges and necrosis in the pads. The left pelvic limb (LPL) suffered minor complications, with involvement of the phalangeal region. After 12 days, with HBOT every 48 h, exuberant granulation tissue was observed. After 17 days, the patient was discharged, and HBOT sessions were performed weekly. Gangrene of the midfoot and lack of proprioception were observed in RPL, while LPL showed bone divulsion of the 1st, 3rd, and 4th phalanges. Because of the poor prognosis for limb viability, the RPL was partially amputated, and a self-threaded intraosseous prosthesis was inserted. Discussion: The cardiorespiratory arrest that occurred during the surgical procedure to reduce the diaphragmatic hernia without thromboprophylaxis may have contributed to the peripheral ischemia. HBOT was proposed for the adjuvant treatment of ischemic injury because it is especially indicated for cases of ischemia-reperfusion injury. The main hematological parameters were evaluated at an average interval of 7 days. While the platelet count and hematocrit increased, the leukocytosis decreased. This demonstrates the benefit of oxygen therapy in the reported patient. The use of HBOT in orthopedic injuries is known to result mainly in stimulation of osteoblasts, promoting osseointegration of the prosthesis. We conclude that the adjuvant treatment with HBOT helped to preserve a large segment of both pelvic limbs, prevent the progression of necrosis, and provide a healthy bed for fixation of an osseointegrated prosthesis in the RPL, resulting in clinical improvement of the patient.

Analgesia perioperatória de gatas submetidas a ovariohisterectomia eletiva - uso preemptivo de carprofeno ou grapiprant / Perioperative analgesia in cats undergoing elective ovariohysterectomy - preemptive use of carprofen or grapiprant

Background: The nonsteroidal anti-inflammatory drugs (NSAIDs) exert their analgesic effect through peripheral inhibition of prostaglandin synthesis and a variety of other peripheral and central mechanisms. However, NSAIDs are associated with some adverse effects, mainly related to the gastrointestinal, renal, and hepatic systems, highlighting the need for research to develop safer drugs. Therefore, the aim of this study was to evaluate the efficacy of preoperative oral administration of carprofen or grapiprant in female cats submitted to elective ovariohysterectomy on the quality of perioperative analgesia and the need for hypnotic and analgesic drugs. Materials, Methods & Results: Thirty-three adult female cats were selected, without defined breed and healthy based on physical examination, routine laboratory analyses (complete blood count, total protein, Heinz body investigation and serum quantification of alanine transaminase [ALT], aspartate transaminase [AST], gamma glutamyl transpeptidase [GGT], alkaline phosphatase [ALP], urea, frutosamine, and glucose) and negative tests for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). After 3 days of adaptation, they were submitted to ovariohysterectomy by celiotomy and randomly allocated into 2 groups according to the preoperative drug used: GCAR [carprofen - 4 mg/kg, VO, 2 h before surgery; n = 11] and GGRA (grapiprant - 2 mg/kg IV, 2 h before surgery; n = 21]. The cats were pre-medicated with acepromazine 0.05 mg/ kg IV and later submitted to general anesthesia with propofol intravenously. Anesthesia was maintained with isoflurane in 100% oxygen. After anesthetic induction, a continuous infusion of remifentanil at a rate of 10 µg/kg/h was initiated. During the transanesthetic period, the parameters of heart rate; respiratory rate; systolic, mean, and diastolic arterial pressure using the oscillometric method; electrocardiogram; rectal temperature; partial pressure of CO2 at the end of expiration: and partial saturation of O2 in hemoglobin were continuously monitored. The evaluation of nociception was based on the changes in the aforementioned physiological parameters. The rate of remifentanil used did not change over time with the use of carprofen. However, animals that received grapiprant required a lower remifentanil dose at 20, 25, and 30 min during the procedure. The female cats that received carprofen showed an increase in mean heart rate at 30 min compared to that at 20 and 25 min. In the Grapiprant group, the heart rate at 35 min was higher only than that observed at 25 min. Discussion: The remifentanil rate did not differ between the groups, even between the times for GCAR. However, the remifentanil rate was lower from 20 min of the procedure for GGRA. This decrease may be related to a decrease in the need for anesthetics and analgesics by decreasing temperature, which causes decreases in metabolism and surgical stimulation. The increase in systolic, mean, diastolic, and heart rate arterial pressure parameters observed in both treatments after 15 min of anesthesia is related to the nociceptive stimulus resulting from traction and ligation of the ovarian pedicles and maneuvers for exteriorization of the uterus. These are considered the moments of greater surgical stimulus during ovariohysterectomy, evidenced by the greater release of cortisol and increase in physiological parameters. The results of this study show that the administration of carprofen or grapiprant was clinically similar when used preemptively for perioperative analgesia in cats submitted to elective ovariohysterectomy.

Systolic blood pressure in anesthetized bitches measured with photoplethysmography

Background: Photoplethysmography is widely used in human medicine, with few studies on its use in veterinary medicine. Its sensor detects fluctuations in blood volume at the site, providing direct readings of cardiac pulse and peripheral oxygen saturation, as well as estimating cardiac output, respiratory rate and blood pressure. This study aimed to evaluate the use of photoplethysmography and compare it to vascular Doppler ultrasound as an indirect method of measuring systolic blood pressure in bitches undergoing elective ovariohysterectomy, using the invasive assessment of systolic blood pressure as a reference. Materials, Methods and Results: After clinical and laboratory evaluation, 34 healthy bitches were selected to undergo elective ovariohysterectomy. After food and water fasting, patients received pethidine hydrochloride intramuscularly as pre-anesthetic medication, followed by anesthetic induction with fentanyl citrate and propofol intravenously. General anesthesia was maintained by inhalation with isoflurane diluted in 100% oxygen. Intraoperative analgesia consisted of continuous infusion of fentanyl citrate intravenously. The animals were randomly divided into 2 groups, the thoracic limb group (TLG) and the pelvic limb group (PLG). In each patient, non-invasive blood pressure measurement was obtained simultaneously with Doppler (DOP) and photoplethysmography (PPG). The sensors of both devices were placed on the end of the same limb. The PPG sensor was positioned in the interdigital region. In patients belonging to the TLG, the Doppler sensor was placed in the ventral region of the thoracic limb, under the ulnar artery. In PLG patients, the Doppler sensor was placed in the dorsal region of the pelvic limb, over the dorsal artery of the foot. The sphygmomanometer was positioned close to the sensors. For systolic blood pressure (SBP) measurement, the cuff was inflated until the Doppler sound signal and the plethysmographic wave were lost. The cuff was then deflated until the Doppler pulse sound resumed and the photoplethysmography showed at least 2 continuous waves on a regular basis. The corresponding pressure value observed on the manometer consisted of the SBP. The same 2 evaluators performed all SBP measurements: 1 responsible for the DOP method and the other for the PPG method; both were blind to the other's findings, thus minimizing potential bias in the results. All animals underwent cannulation of the auricular artery for invasive measurement of systolic blood pressure, using a multiparameter monitor. All blood pressure measurements were performed at 5-min intervals, as well as obtaining additional parameters (heart and respiratory rate, esophageal temperature, partial tissue oxygen saturation, carbon dioxide concentration) and electrocardiographic monitoring. All parameters were documented for further statistical analysis. A strong correlation (r² = 0.95) was obtained between the DOP and PPG methods regardless of the limb on which the sensors were placed. There was a low correlation between the invasive method of measuring systolic blood pressure and the other methods. There was better agreement between the DOP and PPG methods (r2 = -0.0061; P = 0.85) when systolic blood pressure was measured in the TLG. Discussion: In the PLG, the values obtained with the DOP and PPG methods were significantly higher than those obtained with the invasive method, while the values obtained in the TLG differed slightly. It was found that the best measurement site by non-invasive methods was the thoracic limb. It was concluded that the non-invasive methods showed a low correlation with the invasive method; however, both methods had similar characteristics and photoplethysmography can be used to replace the vascular Doppler method.