Do standard monitoring sites reflect true brain temperature when profound hypothermia is rapidly induced and reversed?

BACKGROUND

Brain temperature is closely approximated by most body temperature measurements under normal anesthetic conditions. However, when thermal autoregulation is overridden, large temperature gradients may prevail. This study sought to determine which of the standard temperature monitoring sites best approximates brain temperature when deep hypothermia is rapidly induced and reversed during cardiopulmonary bypass.

METHODS

Twenty-seven patients underwent cardiopulmonary bypass and deep hypothermic circulatory arrest in order for each to have a giant cerebral aneurysm surgically clipped. Brain temperatures were measured directly with a thermocouple embedded in the cerebral cortex. Eight other body temperatures were monitored simultaneously with less invasive sensors at standard sites.

RESULTS

Brain temperature decreased from 32.6 +/- 1.4 degrees C (mean +/- SD) to 16.7 +/- 1.7 degrees C in 28 +/- 7 min, for an average cerebral cooling rate of 0.59 +/- 0.15 degrees C/min. Circulatory arrest lasted 24 +/- 15 min and was followed by 63 +/- 17 min of rewarming at 0.31 +/- 0.09 degrees C/min. None of the monitored sites tracked cerebral temperature well throughout the entire hypothermic period. During rapid temperature change, nasopharyngeal, esophageal, and pulmonary artery temperatures corresponded to brain temperature with smaller mean differences than did those of the tympanic membrane, bladder, rectum, axilla, and sole of the foot. At circulatory arrest, nasopharyngeal, esophageal, and pulmonary artery mean temperatures were within 1 degree C of brain temperature, even though individual patients frequently exhibited disparate values at those sites.

CONCLUSIONS

When profound hypothermia is rapidly induced and reversed, temperature measurements made at standard monitoring sites may not reflect cerebral temperature. Measurements from the nasopharynx, esophagus, and pulmonary artery tend to match brain temperature best but only with an array of data can one feel comfortable disregarding discordant readings.

Colonic and anorectal motility testing in clinical practice

Colonic and anorectal motor activity can be evaluated by a variety of diagnostic techniques. These include anorectal and colonic manometry, radiographic and scintigraphic studies of defecation and continence, colonic transit using radioopaque markers or radioisotopes, neurophysiological studies of pelvic floor striated muscles and pudendal nerves, and anal endosonography. This article reviews these techniques and assesses their value and limitations in evaluating patients with constipation, defecatory disorders, and fecal incontinence.

Cervical antibodies in patients with oral herpes simplex virus type 1 (HSV-1) infection: local anamnestic responses after genital HSV-2 infection

Herpes simplex virus (HSV)-specific immunoglobulin A, immunoglobulin G, and secretory-component-containing immunoglobulins were identified in cervical and salivary secretions from six subjects with oral HSV type 1 (HSV-1) infections. Anamnestic cervical and salivary antibody responses were detected in two HSV-1-seropositive women with newly acquired genital HSV-2 infections. These data implicate the common mucosal immune system in antibody responses to HSV.

Constipation in the elderly: influence of dietary, psychological, and physiological factors

OBJECTIVE

To identify dietary, psychological, and physiological characteristics of older individuals with chronic constipation, compared with a control group of individuals without constipation, and identify correlates of colonic transit time.

DESIGN

Cohort study.

SETTING

University hospital and affiliated clinics.

PARTICIPANTS

Eighteen constipated and 18 control subjects who were nondemented, ambulatory, community-dwelling outpatients over the age of 60 years.

MEASURES

Measures included a 1-week food diary, diet questionnaire, bowel diary, the Hopkins Symptom Checklist (SCL-90R), colonic transit study, and medical history, including queries about activity, medications, medical illnesses, and bowel symptoms.

MAIN RESULTS

Constipated subjects reported consuming fewer meals per day compared with control subjects (P < 0.01) and a tendency to consume fewer calories (P = 0.07). There were no differences between groups on fiber or fluid intake or any of the other dietary parameters. However, slow colonic transit was significantly related to low caloric intake (P < 0.0001), higher percent of protein in the diet (P < 0.05), low fluid intake (P < 0.05), and to psychological symptoms of somatization, obsessive-compulsiveness, depression, anxiety, and the global severity index (P < 0.05). Transit times were unrelated to crude or dietary fiber intake, activity level, or age.

CONCLUSIONS

The data suggest that constipation in this older population is related to caloric intake rather than fiber consumption or other dietary qualities. Psychological distress is associated with slowed colonic transit and should be investigated further as a possible etiologic factor in constipation.

Pathophysiology and management of fecal incontinence

The successful management of fecal incontinence requires an understanding of anorectal function, careful delineation of the disorder by a detailed history and physical examination, and specialized studies of anorectal and pelvic floor function in selected patients. These studies include anorectal manometry, dynamic radiographic studies of the anorectum, pelvic floor neurophysiologic tests and anal endosonography. Therapeutic options include dietary modifications, behavioral programs, pharmacologic agents and surgery. Currently available diagnostic tests should result in optimal management of these patients.

Clinical evaluation and treatment of constipation

Constipation is a symptom but can generally be defined as less than three bowel movements per week. The history and physical examination should be evaluated for stool size, frequency, and straining and discomfort on defecation. The influence of age, gender, and society should also be considered. The etiologies of constipation can be classified as 1. dietary; 2. drug induced; 3. metabolic; 4. neurologic; or 5. anatomic. If hard or small stools are part of the initial evaluation, then a dietary approach of increased dietary fiber intake can be used as a therapeutic trial. If it does not succeed or the history and physical evaluation indicate an etiology other than dietary, then barium-contrast enema, flexible sigmoidoscopy, colonoscopy, transit time, or anorectal manometry can be used selectively in further evaluation. Detailed methods of treatment are described, such as how to increase fiber intake by use of dietary history and recommendation of appropriate fiber, food, or supplement intake. Methods of using behavioral changes such as laxation and toilet-training programs are described. In selected situations pharmacologic therapy and, rarely, surgical intervention, can be useful.

A randomized, double-blind, comparative trial comparing high- and standard-dose oral acyclovir for first-episode genital herpes infections

Orally administered acyclovir ameliorates the clinical course and decreases the duration of viral shedding in patients with first-episode genital herpes infections. We investigated in a randomized, double-blind, comparative trial whether a higher (4 g) than standard (1 g) daily dose of oral acyclovir results in greater clinical benefit and influences the time to first recurrence. A total of 139 patients with first-episode genital herpes were randomized to receive orally 4 or 1 g of acyclovir daily. A total of 52 subjects were excluded from the efficacy analysis because most had recurrent disease. Of 87 eligible subjects, 28 (32%) had primary herpes simplex virus type 1 (HSV-1) infections, 48 (55%) had primary HSV-2 infections, and 11 (13%) had nonprimary HSV-2 infections. We did not find any statistically significant differences in the duration of symptoms or viral shedding between the two dose groups, nor did the median time to first recurrence differ between the two groups. Initiation of therapy with either dose within the first 3 days of the appearance of symptoms shortened the duration of the first episode. Adverse gastrointestinal effects developed in 8% of subjects receiving the higher dose, whereas no adverse reactions were observed among those receiving the standard dose (P = 0.10). We conclude that, in comparison with standard therapy, higher-dose oral acyclovir does not result in additional clinical benefit or modify the time to first recurrence. The present study may have implications for the development and efficacy of congeners of acyclovir which provide higher levels in blood than the standard dose of acyclovir.

Physiologic and psychologic characteristics of an elderly population with chronic constipation

OBJECTIVES

To characterize colorectal physiologic parameters and psychological profiles in subjects > or = 60 yr with chronic constipation who have not sought medical advice.

METHODS

Colorectal physiologic studies and psychologic profiles were obtained in 18 self-identified constipated subjects and 17 nonconstipated control subjects. Constipation was defined as two or fewer bowel movements/week and/or defecatory difficulty for at least 6 months. All subjects underwent colonic transit with radiopaque markers, anorectal manometry and completed a self rated inventory assessing psychological distress (SCL-90-R).

RESULTS

Slow colonic transit occurred in five constipated subjects. Pelvic floor dyssynergia and/or increased rectal compliance were found in nine subjects versus only two controls. One-third of constipated subjects scored in the top 10th percentile for global psychologic distress with higher scores for somatization, depression, and anxiety than control subjects. Neither physiologic nor psychologic abnormalities were predictable on the basis of patterns of bowel complaints.

CONCLUSIONS

Colorectal physiologic and psychologic dysfunctions are common in elderly constipated subjects who do not seek medical attention for bowel dysfunction.

Obesity and weight reduction do not influence gastric emptying and antral motility

A dual radioisotope technique was used to measure gastric emptying of a mixed solid and liquid meal in 30 obese (> 125% of ideal body weight) subjects and 23 age- and sex-matched nonobese control subjects. Gastroduodenal motility studies were also performed on seven obese and 10 nonobese subjects to compare postprandial antral motility. In addition, eight obese subjects underwent gastric emptying studies before and after substantial weight reduction (mean 8.3%). Gastric emptying of both solids and liquids was similar in obese and nonobese subjects, and antral motility indices did not differ between the groups. Gastric emptying rates before and after substantial weight reduction were similar. We conclude that neither gastric emptying nor antral motility appear to be abnormal in morbidly obese subjects; neither does gastric emptying appear to be affected by substantial acute weight reduction.

Constipation in elderly patients. Pathogenesis and management

The incidence of constipation appears to increase with increasing age, particularly after the age of 65. There are few data on the age-related physiological changes of colonic and anorectal function; however, anal sphincter pressures are decreased in elderly patients, while colonic transit time does not appear to be altered. The successful management of constipation in elderly patients requires an understanding of colorectal function, careful characterisation of the patient's complaint, and in selected patients, specialised studies of colonic and anorectal function. The cause of constipation in elderly patients is often multifactorial and may include inactivity, inappropriate diet, depression and confusion, certain medications, and neuromuscular disorders. The treatment of chronic constipation should be based on the nature of the complaint and the presumed pathophysiological mechanisms at work in each patient. Treatment will be based on one or more strategies including dietary changes, laxatives, and in carefully defined cases, surgery.

Scintigraphic studies of rectal emptying in patients with constipation and defecatory difficulty

We prospectively evaluated 38 adult patients with chronic constipation with and without defecatory difficulties using a newly described scintigraphic test to measure rectal emptying and compared them to 20 healthy controls. All patients underwent anorectal manometry, and 30 who complained of infrequent defecation underwent a colonic transit study using radiopaque markers. Control subjects promptly evacuated both 100 ml and 200 ml artificial stool in a characteristic fashion, but three evacuated none of the 100-ml volume and two had no evacuation of the 200-ml stool (inhibited controls). Constipated patients exhibited three patterns of emptying: (1) normal emptying of both volumes (47%); (2) poor emptying of both volumes or inhibited defecation (29%); and (3) normal emptying of the 200-ml but abnormal evacuation of the 100-ml volume (24%). An abnormal expulsion pattern during manometry occurred in 21% of patients and was strongly associated with the inhibited defecation pattern. However, defecation patterns could not be predicted on the basis of age, gender, symptoms, duration of complaints, colonic transit, or other rectal manometric parameters. Although rectal scintigraphy has potential advantages as a diagnostic test in terms of quantitation and decreased radiation exposure, the inability of the test to distinguish patients with slow transit constipation and defecatory complaints makes the potential utility of this test of uncertain value in clinical and investigative settings.

Psychological evaluation of patients with severe idiopathic constipation: which instrument to use

We prospectively evaluated 38 patients with chronic severe idiopathic constipation who failed to respond to conventional therapy. Colonic transit studies, the Hopkins Symptom Checklist (SCL-90-R), and the Minnesota Multiphasic Personality Inventory (MMPI) were completed. Colonic transit studies identified 23 patients with slow transit and 15 with normal transit. Patients with normal transit constipation scored higher than those with slow transit on every scale of both the SCL-90-R and MMPI, but the SCL-90-R appeared to detect greater differences between the two groups. We conclude that the SCL-90-R is the preferred psychological instrument to evaluate patients with chronic severe constipation who fail to respond to conventional therapy. It provides information similar to the MMPI with which to measure behavioral profiles of patients in an office setting, and it can be completed and scored more rapidly.

[Hemi-arthroplasty of the hip joint: concentric or positive eccentric (self-centering) dual head prosthesis? A retrospective comparison]

In femoral neck fractures in the elderly, the least traumatic operative treatment is hemiarthroplasty. In our Trauma Unit, from August 1986 to December 1986 we implanted 22 concentric bipolar cups. During follow-up this cup proved to be associated with an unjustifiably high failure rate: system-caused interprosthetic dislocation in 4 patients (18%), and extraprosthetic dislocation in a further 3 (13%). In one of the latter, interprosthetic disconnection occurred during closed reduction. In all of these, i.e., in 31% out of the 22 patients, conversion to a total hip arthroplasty became necessary. Since March 1987 we have used a positive eccentric, self-centering bipolar head. Up to September 1990 322 such prostheses were implanted. Bearing in mind the reduced general physical condition of the patients, the complication rate is considered to be low (dislocations 3.4%, conversion to total hip arthroplasty 0.9%, deep wound infections 3.1%).

Comparative studies of esophageal function in systemic sclerosis

Three modalities for assessing esophageal dysfunction in patients with systemic sclerosis were prospectively compared. Seventeen patients underwent (a) esophageal manometry with measurement of distal esophageal peak contraction pressure amplitude, percentage of peristaltic waves, and lower esophageal sphincter pressure; (b) cine-esophagography with scoring based on residual contrast and the character of visualized waves; and (c) esophageal transit scintigraphy with quantification of residual swallowed tracer. Highly significant correlations were found between scintigraphic residual and cine-esophagography score, between scintigraphic residual and manometric amplitude, and indeed between all pairs of measured esophageal function parameters except those involving lower esophageal sphincter pressure. In addition, scintigraphy and cine-esophagography showed comparable ability to discriminate between patients with abnormal and normal esophageal motor function. Symptoms did not significantly correlate with quantitative parameters, nor did they have diagnostic discriminating ability. Induction of Raynaud's phenomenon in a subgroup of patients had no detectable effect on esophageal function. It was concluded that these three diagnostic modalities are approximately equivalent in their ability to detect esophageal dysmotility in systemic sclerosis and measure its severity.

Evacuation proctography in normal volunteers

Constipated patients evaluated by evacuation proctography may be subjected to vigorous medical therapy or surgery, even colectomy, based on radiographic findings that have been called "abnormal" in the literature. Criteria for normal defecography are not uniformly established, nor has correlation of structural or functional findings with symptoms been clearly documented. We prospectively studied 21 asymptomatic volunteers to assess the frequency of findings in a control population, and to establish a quantitative measure of normal rectal emptying. Standard defecography technique demonstrated rectocele, intussusception, pelvic descent, or puborectalis spasm in 14/21 volunteers (67%). The range of rectal emptying was 12.5% to 100%, with four subjects (19%) evacuating less than or equal to 40% of the barium paste. There was no correlation between severity of radiographic findings and degree of evacuation. Defecography results in patients being considered for symptomatic intervention should be interpreted cautiously, given the wide range of normal variation in a control population.