Blood pressure monitoring: Automated oscillometric devices

An understanding of the principles of blood pressure measurement with automated oscillometric devices (e.g., Dinamap) allows a user to realize the purpose and level of accuracy for which the equipment is designed. Good technique calls for various actions: (1) using a cuff of proper size (too large a cuff will generally work acceptably, but too small a cuff will yield erroneously high readings); (2) squeezing all of the residual air out of the cuff before applying it to the arm or leg; (3) wrapping the cuff snugly around the arm or leg; (4) instructing the patient to refrain from talking or moving and letting nothing press against the cuff during measurement; (5) keeping the cuff and heart at the same horizontal level. (6) When instrument malfunction is suspected, first checking the status of the patient (not the status of the instrument) to be sure that a clinical emergency is not causing the suspected malfunction; (7) repeating a reading several times when it is suspicious and, if necessary, modifying the measurement conditions by using, for example, different limbs or different cuffs until the question is resolved; and (8) remembering that a leak in the cuff, hoses, or connection can cause an unexpected malfunction.     

Use of A Neonatal Blood Pressure Cuff to Monitor Blood Pressure In The Adult Finger – Comparison With A Standard Adult Arm Cuff

Background. There are few suitable methods for monitoring blood pressure continously (or intermittently) for research in adult stroke patients, who are ill but do not justify invasive intensive care monitoring. Method. We tested a neonatal arm blood pressure in adults by placing it on the forefinger (finger cuff). We compared the repeatability of the finger cuff with blood pressure measured by a standard adult arm cuff using the oscillometric technique in 168 ambulatory outpatients attending a cerebrovascular disease clinic. Results. The mean difference between sequential mean blood pressure readings with the finger cuff was 0.55 mm Hg (95% confidence interval (CI) –14.36 to 15.47 mm Hg), and for the arm cuff was 3.31 mm Hg (95% CI –23.33 to 16.71 mm Hg). Measurements made with the arm cuff were shown to affect subsequent arm cuff readings made within a few minutes of the first. The mean difference between the finger cuff and arm cuff mean blood pressure readings was 0.03 mm Hg (95% CI –26.07 to 26.14 mm Hg) and agreement was better when the blood pressure was measured with the finger cuff first rather than the arm cuff. However, although there was no difference in the mean blood pressure recordings both systolic and diastolic blood pressure measurements differed systematically between arm and finger cuff. Conclusion. The reproducibility of sequential blood pressure measurements made with the finger cuff was better than with the arm cuff. The performance of the finger cuff compared with that of the arm cuff was sufficiently good to encourage use of the finger cuff in research involving automatic intermittent monitoring to observe sequential blood pressures over time in stroke patients. However, measurements of systolic and diastolic pressure were not the same with the two cuffs and further work on calibration of the finger cuff would be useful.     

Severe low-pressure cuff tracheal injury in burn patients

Two cases are presented of severe tracheal damage secondary to low-pressure high-volume endotracheal tube cuffs monitored carefully against over-inflation. Our patients' findings suggest that in the presence of tracheal inhalation injury or severe tracheal infection strict monitoring of pressures, though essential, does not preclude tracheal trauma from a low-pressure cuff, trauma to a degree generally ascribed only to high-pressure stiff cuffs. There is probably no arbitrarily safe level of cuff pressure in these patients; any amount of pressure is likely to further harm the tracheal wall and must be weighed into the risk-benefit equation for prolonged intubation.Partly supported by National Institutes of Health Grant GM 21700     

Impact of Kendall,Hollon, Beck,Hammen, and Ingram (1987) on treatment of the continuity issue in “depression” research

The article, Issues and Recommendations Regarding Use of the Beck Depression Inventory (Kendall, Hollon, Beck, Hammen, & Ingram, 1987), has had a major impact on depression research. A majority of studies using only the BDI in nonclinical samples now refer to the construct measured as dysphoria rather than depression. This word change, however, is not always accompanied by other changes in research design and interpretation that would seem warranted by the concerns that initially prompted the dysphoria recommendation, such as the nonspecificity of high BDI scores to major depression. Researchers typically continue to derive hypotheses from depression theory, use only the BDI to measure dysphoria rather than purer markers of negative affectivity, cite as a limitation of their findings the danger of assuming continuity between subclinical and clinical depression, and sometimes lapse into depression terminology. Alternative suggestions are made for considering how the particular goals of a study might lead to various ways of handling the continuity issue.We are grateful to Tony Ahrens, Diane Arnkoff, and anonymous reviewers for feedback on earlier drafts.     

A clinical evaluation of rapid automatic noninvasive blood pressure determination with the Ohmeda 2120 “return-to-flow” method

Most commercial noninvasive blood pressure devices use the oscillometric method for determination of blood pressure. The Ohmeda 2120 noninvasive blood pressure monitor uses the oscillometric technique, but it also includes a Sys Stat mode for rapid determination of systolic blood pressure up to ten times per minute. This Sys Stat mode uses the return-to-flow method, in which the pressure on an upper arm cuff decreases in small steps until a finger sensor detects the first pulse of blood. Data from 16 patients monitored with the Ohmeda 2120 unit and with an arterial cannula were analyzed. The line of regression was Sys Stat = 0.85 (arterial) + 9.49. The Ohmeda 2120 monitor tended to under-estimate the arterial pressure, particularly at higher pressures. Several factors could have contributed to this underestimation. Even so, the accuracy is sufficient for clinical use under most circumstances. More importantly, in an urgent situation, the Sys Stat mode can provide a reading of systolic blood pressure within seconds.Supported by a grant from Ohmeda.Presented in part as a poster presentation at the annual meeting of the American Society of Anesthesiologists, San Francisco, October 1988.     

Optimizing outcomes with antimicrobial therapy through pharmacodynamic profiling

In patients with infection, improving the probability of positive treatment outcomes depends on optimizing the interactions between the host, pathogen, and drug. In this setting, optimal regimens must be utilized which not only maximize effectiveness in a specific patient, but also minimize the development of microbial resistance. The probability of achieving a specifically targeted antimicrobial exposure can be assessed using Monte Carlo simulation, a technique which integrates an agents in vitro potency distribution (i.e., minimum inhibitory concentrations [MICs]) with the pharmacokinetic profile. The targeted pharmacodynamic parameters assessed by this technique include the ratio of peak concentration (C_max) to MIC (C_max:MIC); the ratio of the area under the plasma concentration-time curve (AUC) to MIC (AUC:MIC), and the time the drug concentration exceeds the MIC (T MIC). Some antimicrobials, e.g., the aminoglycosides, are most effective/bactericidal when they have a high C_max:MIC ratio; others, e.g., the fluoroquinolones, are more effective when the AUC:MIC ratio is high. In both of these scenarios, organism eradication is concentration-dependent, and the therapeutic goal is to maximize drug exposure. Like the fluoroquinolones, the efficacy of telithromycin, a newly developed ketolide, is most related to the AUC:MIC ratio. Outcome for other agents, such as the -lactams, is best predicted by the T MIC; in this case, organism eradication is time-dependent, and the therapeutic goal is to optimize the duration of antimicrobial exposure. This article discusses how the use of currently available antimicrobials can be optimized through an appreciation of pharmacodynamic profiling.     

Obstructive and enteropathic syndromes after jejunoileal bypass surgery

Small bowel bypass procedures for morbid obesity have been associated with many postoperative complications. With the use of the Scott procedure, the bypassed or excluded small bowel segment has recently been the focus of 2 syndromes — bypass enteritis and defunctioned bowel syndrome. We describe these postoperative complications and present their significant radiologic features.     

Negative self-evaluations among dysphoric college students: A difference in degree or kind?

The tendency to engage in globally negative self-evaluations (i.e., overgeneralization) is quite prevalent in depression but the precise nature of this tendency is little understood. This research examined whether the self-evaluations of dysphoric individuals differed in degree or kind from those of nondysphoric individuals. Dysphoric and nondysphoric students imagined themselves in various hypothetical situations and rated how they would evaluate themselves on 49 trait dimensions that varied in globality. Subjects also rated how depressed or happy each situation would make them feel. Subjects then estimated how they would feel and evaluate themselves 3 days after the original negative events. Results showed that the self-evaluations of dysphoric and nondysphoric subjects differed in both degree and kind. That is, dysphoric subjects rated themselves more negatively than nondysphorics across both global and specific traits, but this negativity was particularly pronounced for global traits. Moreover, supporting the position that globally negative self-evaluations influence the persistence of a depressive episode, globally negative thinking by dysphoric subjects predicted their estimated mood 3 days after the imagined negative events, as well as predicting their actual recovery from depression over the course of a 5-week period. Results are discussed as supporting Teasdale's (1988) differential activation hypothesis regarding the onset and persistence of depression.     

Delayed carotid shunt occlusion detected by electroencephalographic monitoring

Little has been recorded in the anesthesia literature concerning the changes in the electroencephalogram (EEG) that may occur during carotid endarterectomy many minutes after shunt placement and restoration of flow and that may be attributed to delayed shunt occlusion or cerebral emboli. We describe a patient in whom EEG changes indicative of cerebral ischemia occurred at the time of carotid clamping. The changes resolved promptly after placement of a carotid shunt but recurred 11 minutes later. Because of the EEG changes, the carotid shunt was evaluated and found to have become occluded. EEG monitoring was crucial to the detection of shunt occlusion in the absence of other systemic changes or surgical difficulties. The rapidity and magnitude of the changes in the EEG suggest that, if the occlusion had not been discovered and the patency of the shunt restored, the patient would have been at increased risk for neurologic injury.     

Implications for Treatment of Sexual Offenders of the Ward and Hudson Model of Relapse

A group of 59 child abusers were classified as having either an avoidant (n = 15) or an approach (n = 44) goal regarding deviant sexual activity with children. Level of distorted beliefs about sexual activity with children (cognitive distortions) and distorted beliefs about their own victims (victim blaming attitudes) in both groups were measured before and after treatment. Results indicate that there was an overall reduction in the level of these distorted beliefs at the posttreatment stage in the approach group. Reductions were not found in the avoidant offenders as men in this group did not have distorted beliefs prior to treatment. Results are discussed in terms of appropriate targeting of treatment.     

Ultrasonic-enhanced gentamicin transport through colony biofilms of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis>

The hypothesis that ultrasound increases antibiotic transport through biofilms of Escherichia coli and Pseudomonas aeruginosa was investigated using colony biofilms. Biofilms grown on membrane filters were transferred to nutrient agar containing 50µg/ml gentamicin. A smaller filter was placed on top of the biofilm and a blank concentration disk was situated atop the filter. Diffusion of antibiotic through the biofilms was allowed for 15, 30, or 45min at 37°C. Some of these biofilms were exposed to 70-kHz ultrasound and others were not. Each concentration disk was then placed on a nutrient agar plate spread with a lawn of E. coli. The resulting zone of inhibition was used to calculate the amount of gentamicin that was transported through the biofilm into the disk. The E. coli and P. aeruginosa biofilms grown for 13 and 24h were exposed to two different ultrasonic power densities. Ultrasonication significantly increased the transport of gentamicin through the biofilm. Insonation of biofilms of E. coli for 45min more than doubled the amount of gentamicin compared to their noninsonated counterparts. For P. aeruginosa biofilms, no detectable gentamicin penetrated the biofilm within 45min without ultrasound; however, when insonated (1.5W/cm²) for 45min, the disks collected more than 0.45µg antibiotic. Ultrasonication significantly increased transport of gentamicin across biofilms that normally blocked or slowed gentamicin transport when not exposed to ultrasound. This enhanced transport may be partially responsible for the increased killing of biofilm bacteria exposed to combinations of antibiotic and ultrasound.     

Early evaluation of coagulase negative staphylococcus in blood samples of intensive care unit patients

Of 2160 intensive care unit patients, 36 patients with positive blood cultures had coagulasenegative staphylococcus in one blood bottle, whereas the organism was present in two or more bottles in 38 cases. The groups were not significantly different in 27 clinical variables, obtained at the time of their first positive blood culture. There was also no significant difference in the antimicrobial sensitivities. No initial clinical data supported the classification of coagulase-negative staphylococcus as either pathogen or contaminant.When the 74 patients with blood culture positive coagulase-negative staphylococcus were compared with three control groups (absent septicemia, probable septicemia and proven septicemia) they were not different from those with probable septicemia. A discriminant analysis was performed comparing patients with absent septicemia and with proven septicemia in an attempt to classify patients with isolates of coagulase-negative staphylococcus in one of these groups at an early stage. Patients with two or more positive blood cultures were not statistically classified more frequently as septicemic than patients with one blood bottle positive for this organism. However, patients categorized as septicemic had a significantly higher mortality (59%) than those classified as non-septicemic (35%) (p<0.05).     

The Use of “As Many As Can” Versus “Feel Like Continuing” Stop Rules During Worrying

Two studies are reported that investigated the processes involved in stopping worry. Study 1 found that the use of as many as can stop rules was significantly related to measures of trait worry and beliefs about the positive and negative consequences of worrying, and Study 2 demonstrated that the reported use of as many as can stop rules significantly predicted perseveration on behavioral measures of catastrophic worrying. Reported use of feel like continuing stop rules was unrelated to any measures of worry in both studies. These results indicate that the use of as many as can stop rules is a highly significant predictor of worry frequency and perseveration, and that beliefs about the positive and negative consequences of worry also independently predict the use of as many as can stop rules. These findings are consistent with (1) the view that the stop rules used by worriers are closely associated with, or directly derived from, the more stable, global beliefs that worriers hold about the utility of the worry process, and (2) predictions from the mood-as-input model of catastrophic worrying (H. M. Startup & G. C. L. Davey, 2001).     

Family functioning and psychological distress among Japanese breast cancer patients and families

Goals of work The purpose of this study was to develop a typology of family functioning in the families of breast cancer patients.Patients and methods Seventy-four families (189 individuals: 74 patients, 54 spouses, 46 offspring, and 15 other relatives) completed self-report questionnaires. Perception of family functioning was assessed using the family relationship index (FRI) and its three dimensions (cohesiveness, expressiveness, and conflict) and was classified into groups by a cluster analytic approach. Psychological distress was assessed using the Zung self-rating depression scale (SDS) and the Zung self-rating anxiety scale (SAS).Main results Cluster analysis yielded three groups of patients and their family members: one cluster with high cohesiveness, high expressiveness, and low conflict (supportive type: n=64); a second group with low cohesiveness, low expressiveness, and high conflict (conflictive type: n=65); and a third group with limited cohesiveness, limited expressiveness, and low conflict (intermediate type: n=60). Analysis of variance revealed that conflictive families manifested the highest level of depression and anxiety among these clusters.Conclusions Typology of family functioning can identify psychologically at-risk families. A family-focused approach can help to reduce psychological distress, especially in conflictive families.     

Self-efficacy expectancies versus outcome expectancies as determinants of performance deficits and depressive affect

To compare the depression etiologies specified by self-efficacy theory versus the revised learned helplessness theory, 108 male and female undergraduates were assigned randomly to either high, low, or no self response expectancy manipulations and high, low, or no response outcome expectancy manipulations. Expectancies were modified by combinations of easy or difficult anagrams and graphs showing that most or few students solved the anagrams. Males exhibited performance deficits and depressed affect following manipulations only if self response expectancy had been set low and other response expectancy had been set high. Contrary to revised learned helplessness theory, no performance deficit or depressive affect occurred when both self response and response outcome expectancies were low. Females' performance and affect were not changed by combined low self response and high response outcome manipulations. Repeated subject ratings of self response and response outcome expectancies during manipulations suggest that females set their self response expectancies low before manipulations to avoid depression. Expectancy ratings also showed that self response expectancies correlated more strongly with performance than did response outcome expectancies.We thank Katherine Acosta, Michael Davis, Larry McFarland, and Janine Tronolone for their assistance as experimenters.     

Effect of rational and irrational beliefs on intensity and “inappropriateness” of feelings: A test of rational—emotive theory

This study tested the central rational-emotive hypothesis that greater inappropriate emotional distress is caused by irrational rather than rational beliefs about undesirable situations. Ellis and Harper (1975) have suggested that inappropriate emotions (such as anger) differ qualitatively from appropriate emotions (such as annoyance). Previous research, however, indicates that irrational beliefs are associated with greater appropriate as well as inappropriate negative emotions. In this study, a 3 ×2 pretest—posttest factorial design was used, in which 10 undergraduates of either sex were randomly assigned to one of three treatments, which involved imagining being in a situation. The control condition comprised an emotionally neutral scene, while the two experimental treatments contained rational and irrational statements about being left alone by one's partner at a party. The experimental manipulation was successful, and both inappropriate and appropriate negative emotions were found to be greater in the irrational condition as compared to the neutral or rational condition. Thus irrational beliefs were shown to have an effect on emotions, but the emotions associated with irrational beliefs differed from those associated with rational beliefs in quantity rather than in quality.     

Percutaneous biopsy of periarterial soft tissue cuffs in the diagnosis of pancreatic carcinoma

Pancreatic cancer may present on computed tomography (CT) as an isolated cuff of tumor surrounding the superior mesenteric artery (SMA) or celiac trunk, without an identifiable pancreatic mass. We reviewed our experience with imaging-guided biopsy of the soft tissue cuff in this patient group. A retrospective review of our interventional database identified 163 patients referred for biopsy of suspected pancreatic carcinoma. Of these, eight patients underwent biopsy of an isolated cuff of soft tissue encasing the SMA (n = 6) or celiac trunk (n = 2). None of these eight patients had an identifiable pancreatic mass. The mean width of tissue cuff biopsied was 1.3 cm (range, 0.9â€2.0 cm). Nine imaging-guided biopsies were performed in eight patients. Five biopsies were performed with color Doppler ultrasound and four with CT fluoroscopy. There was a median of two needle passes per procedure (range, 1â€4). In six cases, a diagnosis of pancreatic adenocarcinoma was made at the first biopsy session. In one patient, ultrasound-guided biopsy was negative, but subsequent CT-guided biopsy was positive. In one additional patient with chronic pancreatitis, biopsy revealed benign fibrous tissue. There were no procedure-related complications. In patients with suspected pancreatic cancer (but without a focal parenchymal mass), imaging-guided biopsy of isolated periarterial tissue cuffs of tumor is accurate and safe.     

New aspects of pulmonary mechanics: ‘slowly” distensible compartments of the respiratory system,identified by a PEEP step maneuver

Objective The aims of the present study were 1) to evaluate a method for identification of slowly distensible compartments of the respiratory system (rs), which are characterized by long mechanical time constants (RC) and 2) to identify slowly distensible rs-compartments in mechanically ventilated patients.Design Prospective studyon a physical lung model.Setting Intensive Care Unit, University Hospital, Tübingen.Patients and participants 19 patients with severe lung injury (acute respiratory distress syndrome, ARDS) and on 10 patients with mild lung injury.Measurements and results Positive end-expiratory pressure (PEEP)-increasing and-decreasing steps of about 5 cmH₂O were applied and the breath-by-breath differences of inspiratory and expiratory volumes (V) were measured. The sequence of Vs were analyzed in terms of volume change in the fast compartment (V_fast), the slow compartment (V_slow), total change in lung volume (VL) and mechanical time constant of the slow compartment (RC_slow). Thirty-eight measurements in a lung model revealed a good correlation between the preset V_slow/VL and V_slow/VL measured: r²=0.91 The V_slow/VL measured amounted to 0.94±0.15 of V_slow/VL in the lung model. RC_slow measured was 0.92±0.43 of the RC_slow reference. Starting from a PEEP level of 11 cmH₂O PEEP-increasing and PEEP-decreasing steps were applied to the mechanically ventilated patients. Three out of ten patients with mild lung injury (30%) and 7/19 patients with ARDS (36.8%) revealed slowly distensible rscompartments in a PEEP-increasing step, whereas 15/19 ARDS patients and 1/10 patients with mild lung injury showed slowly distensible rs-compartments in a PEEP-decreasing step (78.9% vs 10%,P<0.002, chi-square test).Conclusions The gas distribution properties of the respiratory system can be easily studied by a PEEP-step maneuver. The relative contribution of the slow units to the total increase of lung volume following a PEEP step could be adequately assessed. Slowly distensible rs-compartments could be detected in patients with severe and mild lung injury, however significantly more ARDS patients revealed slow rs-compartments in PEEP-decreasing steps. The influence of slowly distensible rs-compartments on pulmonary gas exchange is unknown and has yet to be studied.The work was performed at the Klinik für Anaesthesiologie und Transfusionsmedizin der Universität Tübingen     

The effects of how and why thinking on perceptions of future negative events

Two alternative ways of thinking about future negative events are examined—thinking about how a negative event might come about versus thinking about the underlying reasons why it might happen. Subjects expected to participate in a get-acquainted conversation with a stranger. They were asked to describe the worst possible outcome for the upcoming conversation and explain either how that might happen or why it might happen. In free-form responses, how thinking subjects were more likely to present unstable causes for a bad outcome and to take responsibility for the outcome than were why thinking subjects. These findings are explained in terms of the advantages accruing from perceived control. The effects of how thinking were most pronounced among defensively pessimistic subjects, who typically focus on the possibility of negative outcomes as a way of preparing themselves for stressful situations. The relevance of how and why thinking to clinical techniques like problem solving or cognitive restructuring is discussed.The author would like to thank Nancy Cantor for her many thoughtful comments and suggestions, and Julie Norem for helpful discussions of these ideas.     

The “Torrstick”: A ruler calibrated in millimeters of mercury for measurement of hydrostatic pressure

We have designed and constructed a ruler (Torrstick) calibrated in millimeters of mercury for the measurement of hydrostatic pressure differences. Marks are placed on a measuring stick every 1.34 cm, to afford the best compromise between a column of 0.9% saline solution and a column of blood. Several uses for this ruler are proposed, including the measurement of central venous pressure.