Comparison of two catheter withdrawal speeds during simultaneous urethral pressure profilometry in anesthetized bitches.

Maximal urethral closure pressure, functional profile length, and number of respiratory peaks on the resting urethral pressure profile, expressed as a percentage of those occurring on the bladder pressure recording, were compared at catheter withdrawal speeds of 1 and 3 mm/s in 30 anesthetized bitches. Significant (P less than 0.001) differences were found in maximal urethral closure pressure and percentage of transmission of respiratory peaks between the 2 speeds. Significant difference was not detected in functional profile length.     

The Immediate Effect of Colposuspension on Resting and Stressed Urethral Pressure Profiles in Anaesthetized Incontinent Bitches

The aim of this study was to document what changes in the resting and stressed urethral pressure profile occur in the incontinent bitch with urethral sphincter mechanism incompetence (SMI) immediately after colposuspension. Resting and stressed subtracted simultaneous urethral pressure profilometry was performed immediately pre- and postcolposuspension in 26 bitches diagnosed with SMI. All of the urethral pressure profiles were measured in anaesthetized bitches using a standard technique and two orientations of the catheter transducers (dorsal and left). Readable pre- and postoperative urethral pressure profiles were obtained in 20 of the 26 bitches. Subjective and objective evaluation of the profiles showed significant differences in the profiles pre- and postcolposuspension. Immediately postoperatively there were significant ( P < .05) increases in functional profile length, maximum urethral closure pressure (MUCP), and distance between the bladder neck and the first negative respiratory peak and stressed spike. There was a significant ( P < .001) decrease in the percentage of negative spikes extending below the resting intravesical pressure on the subtracted profile. The pressure transmission profiles were significantly ( P < .001) altered by surgery. The findings presented support the hypothesis that colposuspension may restore continence by increasing pressure transmission to the proximal urethra and bladder neck. The results also suggest that immediately after surgery functional urethral length and urethral resistance are increased.     

Comparison of the effect of propofol and sevoflurane on the urethral pressure profile in healthy female dogs

OBJECTIVE: To compare the effects of propofol and sevoflurane on the urethral pressure profile in female dogs. ANIMALS: 10 healthy female dogs. PROCEDURE: Urethral pressure profilometry was performed in awake dogs, during anesthesia with sevoflurane at 1.5, 2.0, and 3.0% end-tidal concentration, and during infusion of propofol at rates of 0.4, 0.8, and 1.2 mg/kg/min. A consistent plane of anesthesia was maintained for each anesthetic protocol. Maximum urethral pressure, maximum urethral closure pressure, functional profile length, and functional area were measured. RESULTS: Mean maximum urethral closure pressure of awake dogs was not significantly different than that of dogs anesthetized with propofol at all infusion rates or with sevoflurane at 1.5 and 2.0% end-tidal concentration. Functional area in awake dogs was significantly higher than in anesthetized dogs. Functional area of dogs during anesthesia with sevoflurane at 3.0% end-tidal concentration was significantly lower than functional area for other anesthetic protocols. Individual differences in the magnitude of effects of propofol and sevoflurane on urethral pressures were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Sevoflurane is an alternative to propofol for anesthesia in female dogs undergoing urethral pressure profilometry. Use of these anesthetics at appropriate administration rates should reliably distinguish normal from abnormal maximum urethral closure pressures and functional areas. Titration of anesthetic depth is a critical component of urodynamic testing.     

Electromyographic and urethral pressure evaluations: assessment of urethral function in female and ovariohysterectomized female cats

Urethral pressure and electromyographic evaluations were performed in 10 healthy, intact female cats and in 10 healthy, ovariohysterectomized (OVH) female cats. Mean maximum urethral closure pressure was 71.4 +/- 25 cm of water for intact cats and 77.5 +/- 31.3 cm of water for OVH cats. Mean maximum pressure of the proximal 60% of the urethral pressure profile length was 39.2 +/- 7.4 cm of water for intact cats and 32.1 +/- 11.6 cm of water for OVH cats. Mean maximum pressure of the distal 40% of the urethral pressure profile length was 76.2 +/- 27.4 cm of water in intact cats and 80.5 +/- 32.9 cm of water in OVH cats. Significant differences between intact and OVH cats were not found in mean maximum urethral closure pressure, proximal urethral sphincter pressure, or distal urethral sphincter pressure.     

Simultaneous urethral pressure profilometry using microtip transducer catheters in the bitch: A comparison of catheter material

Simultaneous urethral pressure profilometry using an 8FG polyurethane microtip transducer catheter in the bitch is subject to considerable variation, Marked differences occur in the parameters normally measured due to the orientation of the transducers and patient position. It has been suggested that a softer catheter may result in less variation. In this study, a comparison was made between 8FG polyurethane and silicone rubber microtip transducer catheters in 35 bitches. There were significant variations in both maximum urethral closure pressure and functional profile length due to catheter type (P < 0–001). Resting intravesical pressure varied with the recording transducer (P < 0–001) and there was a significant interaction between catheter type and recording transducer (P < 0–001). Radiographic measurements on 15 bitches suggested that variations in recorded intravesical pressure were probably related to the location of the transducers of the two catheters within the bladder. It is concluded that the use of a softer catheter material alone is insufficient to eliminate variations resulting from the orientation of the recording sensors within the urethra.     

Experimental study of urodynamic changes after ovariectomy in 10 dogs

The urodynamic changes in 10 bitches up to 18 months after they had undergone ovariectomy were investigated. There were significant decreases in the maximum urethral closure pressure, the functional urethral length and the total integrated pressure profile 18 months after spaying, resulting in a caudal shift of the urethral profile, and a deterioration of urethral closure function. Each urethral pressure profile was divided into three equal sections; the mean cranial and middle integrated pressure decreased significantly and consistently over the 18-month observation period whereas the caudal integrated pressure increased.     

Influence of the estrous cycle on urodynamic and morphometric measurements of the lower portion of the urogenital tract in dogs

OBJECTIVES: To compare the values of the urodynamic parameters of the lower portion of the urinary tract and vaginourethral measurements obtained during the phases of the estrous cycle in dogs and determine possible functional or anatomic modifications of the lower portion of the urinary tract associated with those phases. ANIMALS: 7 adult female Beagles. PROCEDURE: Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed in each dog during proestrus; estrus; early, mid, and late diestrus; and early and late anestrus. The maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP), urethral functional and anatomic profile lengths (UFPL and UAPL, respectively), integrated pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. RESULTS: For all measurements, significant interindividual variation was detected. Integrated and threshold pressures, APL, and each morphometric value significantly increased from late anestrus to proestrus. Compared with other phases, MUP, MUCP, and integrated pressure values were significantly lower in estrus and early diestrus; UAPL and UFPL values were significantly lower in late diestrus. At each cycle phase in old dogs, MUP, MUCP, threshold pressure, and vaginal length and width were significantly lower (except in proestrus for vaginal measurements) and threshold volume and compliance values were significantly higher, compared with middle-aged dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Urodynamic and morphometric measurements of the lower portion of the urogenital tract are affected by the changes in hormonal balance that occur during the estrous cycle. In sexually intact female dogs, estrous phase determination is important for the interpretation of urodynamic data.     

Urethral pressure profilometry in mares

A technique was developed for recording urethral pressure profiles (UPP) in mares. Profiles were obtained from 12 clinically normal mares and from 3 mares with urinary incontinence. Variables measured on the profile included intravesicular pressure and maximal urethral closure pressure. The mean maximal urethral closure pressure of the incontinent mares was significantly less (P less than or equal to 0.001) than that of the normal mares. The technique is simple and reliable for objectively evaluating urethral pressures in mares.     

Urethral pressure profilometry in the anaesthetised bitch: a comparison between double and single sensor recording

A comparison was made between urethral pressure profiles obtained using a single sensor and 'subtracted' urethral pressure profiles resulting from double sensor recordings in 50 bitches. There were small but significant differences in the functional profile lengths and maximum urethral closure pressures between the two types of recording. The differences were partially explained by a significant fall in the intravesical pressure recorded during profilometry and variations due to respiration. The profiles from single and double sensor recording were of equal significance in the diagnosis of sphincter mechanism incompetence.     

Clinical response and urethral pressure profile changes after phenylpropanolamine in dogs with primary sphincter incompetence

Based on clinical response, urethral pressure profile changes, and lack of side effects, phenylpropanolamine was effective and safe in treating dogs with primary sphincter incompetence. Primary sphincter incompetence was diagnosed in 11 female and 8 male dogs with urinary incontinence. Urodynamics of the dogs were assessed, using a combined urethral pressure profile and urethral sphincter electromyography. Male and female dogs had significantly (P less than 0.05) lower maximal urethral closure pressures, when compared with clinically normally dogs (36.91 +/- 8.20 cm of H2O vs 79.72 +/- 4.61 cm of H2O for female dogs and 48.63 +/- 8.68 cm of H2O vs 99.77 +/- 11.71 cm of H2O for male dogs). After treatment with phenylpropanolamine, there was a significant increase in maximal urethral closure pressure in both sexes to within normal range (77.73 +/- 8.70 cm of H2O in females and 92.50 +/- 14.60 cm of H2O in males). Electromyographic activity was normal before and after treatment. Urinary incontinence resolved clinically in all but 1 male and 1 female dog; however, the condition in these 2 dogs improved considerably. Minimal side effects were seen clinically. Mean arterial blood pressure was not altered by treatment. Plasma estrogen and testosterone concentrations in 8 female dogs were not different from those in continent female dogs. The incontinence in these dogs was considered a sphincter incompetence rather than estrogen responsive.     

Evaluation of the urodynamic and hemodynamic effects of orally administered phenylpropanolamine and ephedrine in female dogs

OBJECTIVE: To compare the urodynamic and hemodynamic effects of different dosages of phenylpropanolamine and ephedrine and determine effective dosages in increasing urethral resistance in female dogs. ANIMALS: 20 sexually intact female Beagles. PROCEDURE: Dogs were allocated into 4 groups and received phenylpropanolamine once, twice, or 3 times daily, or ephedrine twice daily, for 14 days. On days 0, 7, and 14, urethral pressure profiles were performed while dogs were anesthetized with propofol. Variables recorded included maximum urethral pressure, maximum urethral closure pressure, integrated pressure, functional profile length, anatomic profile length, plateau distance, distance before maximum urethral pressure, and maximum meatus pressure. Arterial and central venous pressures were measured before anesthetic induction and 10 and 35 minutes after induction. RESULTS: Administration of phenylpropanolamine once daily or ephedrine twice daily significantly increased maximum urethral pressure and maximum urethral closure pressure. Values for integrated pressure were significantly increased after 14 days of once-daily administration of phenylpropanolamine. Variables did not change significantly from day 7 to day 14. Diastolic and mean arterial blood pressures increased significantly during the treatment periods, and arterial pressure decreased during propofol infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of phenylpropanolamine once daily or ephedrine twice daily increased urethral resistance in clinically normal dogs and may be recommended for management of urethral sphincter mechanism incompetence. Treatment efficacy may be assessed after 1 week. Dogs with concurrent cardiovascular disease should be monitored for blood pressure while receiving alpha-adrenergic agents because of the effects on diastolic and mean arterial pressure.     

Urodynamic and morphologic changes in the lower portion of the urogenital tract after administration of estriol alone and in combination with phenylpropanolamine in sexually intact and spayed female dogs

OBJECTIVE: To compare the urodynamic and morphologic effects of the administration of estriol alone and in combination with phenylpropanolamine on the lower portion of the urogenital tract in female dogs. ANIMALS: 3 sexually intact and 3 spayed female Beagles without urinary incontinence. PROCEDURE: Dogs received estriol (2 mg, PO) once daily for 7 days followed by estriol (2 mg, PO) and phenylpropanolamine (1.5 mg/kg, PO) once daily for 7 days. Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed before treatment (day 0) and at days 7 and 14. The maximum urethral pressure (MUP) and closure pressure (MUCP), urethral functional and anatomic profile lengths, integrated pressure (IP), plateau, distance before MUP, maximum meatus pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. RESULTS: Before treatment, no urodynamic differences were observed between the 2 groups; however, vaginal length and width were significantly shorter in spayed dogs. Compared with day 0 values, estriol treatment significantly increased MUP, MUCP, and IP values at day 7, but at day 14, this effect decreased despite phenylpropanolamine administration. No morphologic changes from baseline were detected after either treatment in any dog. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggest that estriol mainly acts on the urethral sphincter mechanism by increasing urethral resistance in sexually intact and spayed female dogs without urinary incontinence. Administration of estriol and phenylpropanolamine did not increase the urethral resistance more than estriol alone. The urodynamic effects of estriol in female dogs with urinary incontinence remain to be elucidated.     

Immediate urodynamic and anatomic response to colposuspension in female Beagles

OBJECTIVE: To characterize urodynamic function and anatomy before and after colposuspension in anesthetized female Beagles. ANIMALS: 12 adult female Beagles. PROCEDURE; During general anesthesia (thiopental sodium induction and halothane maintenance), urethral pressure profiles, leak point pressure measurements with a 50-ml bladder volume, positive contrast cystograms, and retrograde vaginourethrocystograms were performed. A caudal midline laparotomy was used to perform colposuspension. Urodynamic and radiographic studies were repeated after surgery. RESULTS: Leak point pressures were increased (120 to 168.9 cm H2O), and maximum urethral closure pressures decreased (43.7 to 19.3 cm H2O ) after colposuspension. The urethra and bladder were moved cranially; the external urethral orifice was positioned closer to the pelvic cavity, and the neck of the bladder was positioned more cranially into the abdomen. Length of the urethra, as measured by use of vaginourethrocystograms, was increased by 3%. As measured by use of urethral pressure profiles, total profile length was increased by 19.9%, and functional profile length was increased by 19.2%. CONCLUSIONS AND CLINICAL RELEVANCE: Increased leak-point pressure correlated with the expected clinical improvement attributable to colposuspension. Increased exposure of the urethra to abdominal and pelvic cavity pressures may be the mechanism by which incontinent dogs become continent after colposuspension. Results of the leak-point pressure test may correlate with clinical behavior before and after colposuspension for treatment of incontinence.     

Effects of xylazine on the urethral pressure profile of healthy dogs

Thirteen healthy male dogs and 11 healthy female dogs were subjected to urodynamic assessment, using a simultaneous urethral pressure profile and urethral sphincter electromyogram (EMG). The study was done on the dogs in the nonsedated state and after xylazine sedation. Results showed a significant decrease in maximal urethral closure pressures in dogs of both sexes after they were given xylazine (from 79.79 cm of H2O to 23.00 cm of H2O in female dogs, and from 99.77 cm of H2O to 41.77 cm of H2O in male dogs). There was a significant reduction in EMG activities in dogs of both sexes after they were given xylazine. There was also little variability in measurements made on the same dog on consecutive days. Simultaneous intravesicular pressure and urethral pressure monitoring indicated that the effect of bladder distention on the urethral pressure profile was minimal and that there were no spontaneous detrusor contractions. This study indicates that xylazine produced a significant artifact in the simultaneous urethral pressure profile/EMG.     

Results of cystometry and urethral pressure profilometry in dogs sedated with medetomidine or xylazine

OBJECTIVE: To compare effects of medetomidine and xylazine hydrochloride on results of cystometry and micturition reflexes in healthy dogs and results of urethral pressure profilometry (UPP) in sedated and conscious dogs. ANIMALS: 20 dogs. PROCEDURES: Urodynamic testing was performed 6 times in each dog (3 times after administration of xylazine [1 mg/kg of body weight, IV] and 3 times after administration of medetomidine (30 microg/kg, IM). Before each episode of sedation, UPP was performed. Heart and respiratory rates and indirect blood pressures were recorded prior to and 5, 10, 20, and 30 minutes after injection of sedative. Cystometry measurements included threshold volume, threshold pressure, and tonus limb. The UPP measurements included maximal urethral closure pressure (MUCP), functional profile length, and, in male dogs, plateau pressure. RESULTS: Mean MUCP was decreased markedly in xylazine- and medetomidine-sedated dogs. Xylazine and medetomidine also decreased plateau pressure in male dogs. The MUCP measurements were consistent among days for conscious and xylazine-sedated dogs but were inconsistent for medetomidine-sedated female dogs. The proportion of valid cystometry measurements was greater for xylazine (39 of 60) than for medetomidine (27 of 60). Cystometry was considered invalid when bladder pressure reached 30 cm H2O without initiation of a micturition reflex. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine and xylazine have similar effects on measurement of UPP and cystometry. Medetomidine was less consistent among days for UPP in female dogs and produced fewer valid cystometry tests, compared with xylazine. For urodynamic evaluations, medetomidine administered IM cannot be substituted for xylazine administered IV.     

Validation and comparison of the use of diuresis cystometry and retrograde filling cystometry at various infusion rates in female Beagle dogs

OBJECTIVES: To compare retrograde filling cystometry at infusion rates of 5, 10, and 20 mL/min with diuresis cystometry for determination of an appropriate infusion rate and to confirm the reproducibility of measurements obtained by urethral pressure profilometry (UPP) and cystometry in female Beagles. ANIMALS: Adult female Beagles. PROCEDURE: Successive UPP and cystometry were performed by use of a water perfusion catheter on dogs anesthetized with propofol. Dogs randomly underwent each of the following at 1-week intervals: retrograde filling cystometry at 5, 10, and 20 mL/min, and diuresis cystometry. The maximum urethral pressure and closure pressure, functional and anatomic profile lengths, threshold pressure, threshold volume, and compliance were measured. RESULTS: For each UPP variable, significant differences were found among dogs, but no significant differences were found in intra- or interstudy measurements for individual dogs. For retrograde filling cystometry, threshold pressure was not significantly different between a 5 and 10 mL/min infusion rate. Threshold pressure was significantly higher during retrograde filling cystometry at 20 mL/min, compared with 5 and 10 mL/min, and was associated with bladder wall damages. Threshold pressure was significantly lower during diuresis cystometry, compared with retrograde filling cystometries. Threshold volume and compliance were not significantly different among retrograde filling cystometries but were significantly higher during diuresis cystometry. CONCLUSIONS AND CLINICAL RELEVANCE: Retrograde filling cystometry at 20 mL/min leads to unacceptable sudden increase in threshold bladder pressure. Retrograde filling cystometry at 10 mL/min can be recommended in a clinical setting, shortening the anesthesia time. However, diuresis cystometry approximates physiologic bladder filling most accurately.     

Comparison of incisional bursting strength of simple continuous and inverted cruciate suture patterns in the equine linea alba

OBJECTIVE: To determine the bursting strength of ventral median abdominal incisions closed by either simple continuous or inverted cruciate suture patterns. STUDY DESIGN: Experimental. ANIMAL OR SAMPLE POPULATION: Twelve equine cadavers. METHODS: A 25 cm ventral median incision was made through the linea alba and a 200 L polyurethane bladder was placed within the abdomen. Either a simple continuous or an inverted cruciate pattern using 3 polyglactin 910 with a bite size and suture interval of 1.5 cm was used to close linea incisions. Closure time was recorded for each pattern. The bladder was inflated with air at 40 L/min, and the pressure at body wall failure recorded. The length of suture used for wound closure and the wound failure modes were recorded. Deviation from the linea (cm), total suture length (cm), suture length to wound length ratio (SL:WL), closure time (min), bursting pressure (mm Hg), and failure modes were compared between groups using Welch-Aspin t-tests. The effects of independent subject variables were assessed for possible effects on bursting strength using analysis of covariance. RESULTS: Mean bursting pressure was significantly greater for the simple continuous pattern than for the inverted cruciate pattern (P = .01). Significantly less suture material (P = .0002) was required with the continuous pattern than with the inverted cruciate pattern. Mean closure time, SL:WL, deviation from the linea, and failure modes were not significantly different between groups. No significant effects were noted for independent variables in both groups on bursting strength. CONCLUSIONS: In this model, a simple continuous closure pattern for ventral median abdominal incisions was stronger than an inverted cruciate pattern. A simple continuous pattern leaves less foreign material in the wound, which may be of benefit in reducing incisional complications. CLINICAL RELEVANCE: Use of a continuous closure pattern for the linea alba may offer greater wound security during episodes of increased intra-abdominal pressure in horses.     

Use of fine-wire electrodes for electromyographic evaluation of the external urethral sphincter during urethral pressure profilometry in male cats

Evaluation of urethral pressure profilometry (UPP) with simultaneous fine-wire electromyography of the external urethral sphincter (EUS) was conducted in 11 healthy adult male cats sedated with xylazine and ketamine. A 3.5-F urethral catheter with a closed end and two 1-mm side-ports was infused with sterile 0.9% NaCl solution at a rate of 2 to 3 ml/min. A fine-wire electromyographic (EMG) electrode was placed percutaneously into or near the external urethral sphincter prior to the onset of the UPP. The maximal urethral pressure achieved and functional profile length were recorded from UPP. Setting both catheter withdrawal rate and paper speed at 5 mm/s enabled the measurement of actual urethral length directly from UPP. Sphincter EMG activity was rated as slight (+), moderate (+ +), or intense (+ + +). All recordings were replicated once during each trial for 8 cats and trials were replicated 5 to 7 days later in 4 cats. Before catheterization, EMG activity of the external urethral sphincter was rated slight (+), whereas intense (+ + +) activity accompanied insertion. The activity evoked by movement of the catheter subsided, but intense EMG activity of the external urethral sphincter was recorded from onset to completion of catheter withdrawal in all cats in both trials. The mean maximal urethral pressure was 93.1 +/- 13.29 cm H2O. The mean function urethral length was 8.1 +/- 0.93 cm. Maximal urethral pressure or function profile length did not differ significantly between recordings within trials or between trials. Simultaneous recording of EMG activity and UPP of the external urethral sphincter was shown to be a simple, noninvasive technique for assessing neuromuscular and anatomic urethral function.     

Cystometrography and urethral pressure profiles in healthy horse and pony mares

Cystometrography and urethral pressure evaluations were performed in 7 horse mares and 5 pony mares before and after sedation with xylazine. Before sedation, mean (+/- SD) maximal bladder contraction pressure was 91.4 +/- 16.5 cm of H2O in horses and was 86.0 +/- 14.4 cm of H2O in ponies, and maximal urethral closure pressure was 49.1 +/- 19.4 cm of H2O in horses and 37.7 +/- 14.4 cm of H2O in ponies. A significant difference was not found between values of nonsedated vs sedated animals. Only values for threshold volume were significantly different (P less than 0.05) between nonsedated horses (1,982 +/- 1,241 ml) and ponies (825 +/- 412 ml).