Baroreflex function in females: changes with the reproductive cycle and pregnancy.

This review briefly describes the changes in baroreflex function that occur during female reproductive life, specifically during the reproductive cycle and pregnancy. The sensitivity or gain of baroreflex control of heart rate and sympathetic activity fluctuates during the reproductive cycle, reaching a peak when gonadal hormone levels increase, during the follicular phase in women and proestrus in rats. The increase in baroreflex sensitivity (BRS) is likely mediated by estrogen because ovariectomy in rats eliminates the BRS increase, the cyclic profile of changes in BRS mirror the changes in estrogen, and estrogen acts in the brainstem to increase BRS.

Pregnancy impairs baroreflex control of heart rate in rats: role of insulin sensitivity.

Recent studies in rabbits suggest that insulin resistance and reduced brain insulin contribute to impaired baroreflex control of heart rate (HR) during pregnancy; however, the mechanisms are unknown. The rat model is ideal to investigate these mechanisms because much is known about rat brain baroreflex neurocircuitry and insulin receptor locations. However, it is unclear in rats whether pregnancy impairs the HR baroreflex or whether insulin resistance is involved.

Baroreflex sensitivity varies during the rat estrous cycle: role of gonadal steroids.

Baroreflex sensitivity (BRS) increases in women during the luteal phase of the menstrual cycle, when gonadal hormones are elevated, but whether a similar cycle-dependent variation in BRS occurs in rats is unknown. In addition, whether cyclic BRS changes depend on gonadal steroids has not been previously investigated. To test these hypotheses, BRS was determined in cycling female rats using two approaches: 1) baroreflex control of renal sympathetic nerve activity (RSNA) in anesthetized rats; 2) cardiovagal spontaneous BRS (sBRS) in conscious rats instrumented for continuous telemetric measurements of mean arterial pressure (MAP) and heart rate (HR).

Tracheostomy after anterior cervical spine fixation.

Background: Patients with cervical spine injury may require both anterior cervical spine fusion and tracheostomy, particularly in the setting of associated cervical spinal cord injury (SCI). Despite the close proximity of the two surgical incisions, we postulated that tracheostomy could be safely performed after anterior spine fixation. In addition, we postulated that the severity of motor deficits in patients with cervical spine injury would correlate with the need for tracheostomy.

Enterocutaneous fistula and ventral hernia after absorbable mesh prosthesis closure for trauma: the plain truth.

Hypothesis: The severity of abdominal injury is the determining factor for the development of enterocutaneous fistula and ventral hernia after absorbable mesh prosthesis closure (AMPC) for trauma.

Methods: We conducted a retrospective analysis of case series that included 140 consecutive trauma patients with AMPC surviving more than 48 hours from October 1, 1989, to March 31, 2000, at a Level I trauma center. The days until abdominal wall reconstruction was used as a measure of exposure of the viscera to the mesh.

Mechanism of acute ascites formation after trauma resuscitation.

Background: Severely injured patients have been observed to acutely develop ascites; however, the pathogenesis of this rare phenomenon is poorly understood.

Objectives: To report the factors common among severely injured patients developing ascites and to formulate a hypothesis regarding its origin.

Methods: Retrospective review of case series.

Medical management of abdominal compartment syndrome: case report and a caution.

We report the case of a 55 year old woman who developed abdominal compartment syndrome [ACS] following total gastrectomy for caustic ingestion. Contributing factors for the development of ACS included peritonitis and massive fluid resuscitation for cardiovascular support of septic shock. The adverse cardiovascular and pulmonary effects of intra-abdominal hypertension [IAH] were reversed with pharmacological neuromuscular blockade [NMB].

Tracheal stenosis after percutaneous dilational tracheotomy.

Objective: In many critical care units percutaneous dilational tracheotomy (PDT) has become an alternative to open tracheotomy. Although significant tracheal stenosis after PDT has been reported, the exact incidence is unknown. We report our findings on endoscopic laryngotracheoscopy for a group of patients who had undergone PDT more than 6 months before their examination.