PubMed Health⌕ Search

Biomedical subjects

R P Hackett

Publications and source records attributed to R P Hackett.

At least 37 records · Page 2Linked to original sources
PubMed1990

Pulmonary shunting by the bronchial artery in the anaesthetized horse.

In the quietly standing horse the bronchial arterial blood flow is low, 0.1-0.2% of the pulmonary arterial flow. In horses anaesthetized with halothane, the bronchial arterial flow is reduced by a greater fraction than that in the pulmonary artery. Thus the shunting through the bronchial circulation is decreased about 3-fold by anaesthesia, and cannot, therefore, contribute significantly to the increased alveolar-arterial gradient seen in dorsal recumbency. The results indicate bronchial vasoconstriction under anaesthesia.

Anesthesia↗
PubMed1990

Clinical evaluation of laryngeal sensation in horses.

Sensory innervation of the larynx was examined by tactile stimulation with a blunt biopsy forceps passed through a flexible videoendoscope. Twenty horses with no evidence of laryngeal motor deficit were stimulated on 10 sites by touch with the forceps. Unilateral neurectomies of the internal branch of the left cranial laryngeal nerve were performed on 5 other horses. These horses were stimulated by touch on the same sites preoperatively and up to 1 week postoperatively. In all 25 horses the motor response of the larynx was recorded on videotape and evaluated by 2 observers blind as to treatment and time of evaluation. Normal horses responded to touch by adduction of both arytenoid cartilages, swallowing or both. This response was not altered by sedation with xylazine hydrochloride. Left cranial laryngeal neurectomized horses failed to respond to tactile stimulation of the left side, while adduction of both cartilages, swallowing or both was observed following stimulation on the right side. Laryngeal stimulation by touch with a biopsy forceps was accurate in identifying horses with complete deficits of the internal branch of the cranial laryngeal nerve.

Animals↗
PubMed1989

Chronic ileocecal intussusception in horses.

Ten young horses with signs of simple partial obstruction of the small intestine were found upon surgical exploration of the abdomen to have chronic intussusception of the distal ileum into the cecum. Poor general physical condition, intermittent or continual abdominal pain of varying degree, depression, and poor appetite were consistent clinical findings. Rectal palpation in eight animals was suggestive of an incomplete or intermittent obstruction of the small intestine. Laboratory determinations were not helpful in making a diagnosis. Dilatation and hypertrophy of the distal jejunum and ileum were associated surgical findings indicating chronicity of the problem. Surgical correction utilizing an end-to-side or a side-to-side anastomosis of small intestine to cecum resulted in recovery in 7 of 8 cases which could be followed long term. Failure to resect the abnormal segment of small intestine did not affect the outcome.

Animals↗
PubMed1986

Nasal obstruction caused by cystic nasal conchae in cattle.

Four Holstein heifers were found to have partial nasal obstruction caused by bilateral cystic conchae. Three of the heifers (age range, 4 to 6 months) had a history of progressive nasal obstruction since near birth, were affected severely, and required surgical management. Each of 2 surgical procedures, a bilateral dorsolateral nasal flap approach and a dorsal nasal flap approach, was used successfully. The fourth heifer, which was 15 months old, had signs of nasal obstruction since shortly after birth, but was affected only mildly and was not treated. Follow-up information obtained 10 to 37 months later revealed that all cattle were considered normal and had no signs of nasal obstruction. In each case, a developmental problem or malformation of the ventral nasal concha resulting in cystic enlargement was suspected. The onset of clinical signs early in life and the bilateral nature suggested that the defect was of congenital origin.

Airway Obstruction↗
PubMed1985

Tracheal rupture in two horses.

Two horses were admitted for evaluation of diffuse SC emphysema. Diagnosis of ruptured trachea was made by tracheoscopy and radiography. The tracheal cartilages were not involved in either case. One of the defects was small and responded to medical management. The other defect was large and was apposed surgically. Both horses recovered without complications.

Animals↗
PubMed1985

Neoplasia of the equine urinary bladder as a cause of hematuria.

In 6 horses with urinary bladder neoplasms, common clinical findings included a palpable mass in the bladder, anemia, hematuria, and/or proteinuria. Squamous cell carcinoma was found in 4 horses and appears to be the most common bladder tumor in the horse. Single cases of transitional cell carcinoma and fibromatous polyp also were identified. All horses except one were over 10 years of age. In one mare, treatment with 5-fluorouracil intracystically resulted in decreased bleeding from the bladder mass and apparent stabilization of the mass size. The mare ultimately died because of abdominal metastasis. Although rare, neoplasia of the urinary bladder should be considered when evaluating horses with hematuria.

Animals↗
PubMed1983

Nonstrangulated colonic displacement in horses.

Nonstrangulated colonic displacement was diagnosed by exploratory celiotomy in 32 horses with acute abdominal pain. Clinical signs progressed slowly and included evidence of mild to moderate abdominal pain, good cardiovascular status, reduced intestinal sounds, and normal peritoneal fluid, and resembled those of colonic impaction. In most horses, rectal palpation supported a diagnosis of colonic obstruction but not a diagnosis of colonic impaction.

Animals↗
PubMed1981

Metabolic abnormalities associated with rupture of the urinary bladder in neonatal foals.

Rupture of the urinary bladder was diagnosed in 4 neonatal male foals. Marked hyponatremia, hypochloremia, and hyperkalemia developed in all 4 cases, and the electrolyte abnormalities were considered to be of potential diagnostic value. Blood urea nitrogen concentration was normal or only slightly higher than normal in 3 of 4 cases and therefore was not a reliable diagnostic test.

Animals↗
PubMed1981

Identification of cartilage wear fragments in synovial fluid from equine joints.

Synovial fluids from 72 equine joints were examined for the presence of cartilage debris, and these findings were compared to findings from visual inspection of the articular cartilage surfaces at necropsy. Synovial fluids from 25 joints with visual cartilage damage contained one or more large particles of articular cartilage. Cartilage fragments were not found in synovial fluids from 42 of the 47 apparently normal joints; thus, a correlation may exist between cartilage debris in the synovial fluid and lesions of the articular surfaces.

Animals↗
PubMed1980

Avulsion fractures of the origin of the suspensory ligament of the horse.

Five horses with avulsion fractures of the proximal origin of the suspensory ligament were examined for lameness. The horses in the series each had lameness of acute onset; four were severely lame, and one was moderately lame. The condition was difficult to diagnose because commonly used local anesthetic blocks did not result in improvement during the routine examination. Local infiltration of the area with local anesthetic returned the horses to soundness. After a period of rest, varying from a few weeks in the acute injury to 6 months in the chronic injuries, the horses were returned to racing without lameness.

Animals↗
PubMedDate not supplied

An in vitro comparison of cordopexy, cordopexy and laryngoplasty, and laryngoplasty for treatment of equine laryngeal hemiplegia.

OBJECTIVE: To examine the effect of cordopexy, laryngoplasty, and cordopexy combined with a modified laryngoplasty on airway mechanics. STUDY DESIGN: Experimental airway mechanics were determined by subjecting equine cadaveric larynges to airflows similar to inspiratory airflow of exercising horses. ANIMALS OR SAMPLE POPULATION: Twenty equine larynges. METHODS: Using cadaveric larynges, we developed and tested a new technique of arytenoid cartilage abduction. All larynges had the right arytenoid cartilage abducted to mimic the degree of arytenoid abduction that occurs at maximal exertion in live horses. Three surgical techniques were used to stabilize the left arytenoid cartilage of treated larynges; the left arytenoid cartilage was not stabilized in control larynges. Technique 1: Cordopexy--a suture was placed between the vocal ligament and the lamina of the thyroid cartilage. Technique 2: Standard laryngoplasty--a suture was placed between the muscular process of the arytenoid cartilage and the caudomedial aspect of the cricoid cartilage. Technique 3: Cordopexy plus modified laryngoplasty--the cordopexy suture was placed with a second suture between the horizontal ridge rostral to the muscular process of the left arytenoid cartilage and the lamina of the thyroid cartilage. Translaryngeal impedances (TI) were determined for each surgical technique by subjecting the larynges to increasing airflows and measuring the translaryngeal pressure differences. The arytenoid right to left angle quotient (RLQ) and the glottic cross-sectional area (CSA) were also measured. RESULTS: At maximal airflow, the adjusted means for the arytenoid RLQ and the TI for the cordopexy plus modified laryngoplasty (1.48 +/- 0.04, 0.69 +/- 0.05 cm H2O/L/s) and the standard laryngoplasty (1.39 +/- 0.04, 0.78 cm H2O/L/s) were different (P < .05) from values obtained after cordopexy alone (2.74 +/- 0.37, 1.76 +/- 0.48 cm H2O/L/s) or in control larynges (3.66 +/- 0.54, 4.16 +/- 0.96 cm H2O/L/s). Overall, a cordopexy plus modified laryngoplasty (9.69 cm2), a standard laryngoplasty (9.34 cm2), and a cordopexy alone (9 cm2) resulted in an increased glottic CSA greater than that for control larynges (6.94 cm2; P = .0001). CONCLUSIONS: Cordopexy alone did not improve airflow in a left laryngeal hemiplegic model. Cordopexy plus modified laryngoplasty was as efficacious as the standard laryngoplasty in alleviating the effects of left laryngeal hemiplegia on TI, glottic CSA, and arytenoid RLQ. CLINICAL RELEVANCE: Fixation of the vocal cord (cordopexy) in addition to a laryngoplasty procedure may prove useful in the surgical treatment of equine laryngeal hemiplegia.

Animals↗
PubMedDate not supplied

Ileocolostomy. A technique for surgical management of equine cecal impaction.

Several surgical alternatives have been described for the management of cecal impaction in the horse, but none has met with consistently successful results. This study was done to evaluate a surgical bypass of the cecum by anastomosis of the ileum to the right ventral colon (ileocolostomy). A ventral midline celiotomy was performed on nine adult ponies (155-350 kg) and a mechanically stapled 10 cm side-to-side ileocolostomy was created. In five ponies a complete cecal bypass (CCB) was created by transecting the ileum distal to the anastomosis. In the other four, an incomplete cecal bypass (ICB) was created with no interruption of the ileum. Six horses with clinical cecal impaction also underwent cecal bypass procedures. Five had a CCB and one had an ICB. All the ponies maintained body weight, had no change in consistency of the feces and had no abdominal pain during the 6 month observation period. At necropsy, the lengths of the lateral cecal band, lateral free band of the colon, and the diameter of the anastomotic stoma were compared to measurements made at surgery. The lateral cecal band length decreased significantly more in the CCB ponies than in the ICB ponies (p = 0.008). The anastomotic stoma diameter was significantly larger in the ICB group than in the CCB group (p = 0.032). Five of the six clinical cases recovered and returned to their previous activity. CCB by an ileocolostomy resulted in removal of the cecum from the functional flow of ingesta without complication in the ponies, and was successful in five clinical cases of cecal impaction.

Anastomosis, Surgical↗