Traditional Vital Signs Research Articles

Change in pulse transit time and pre-ejection period during head-up tilt-induced progressive central hypovolaemia

Traditional vital signs such as heart rate (HR) and blood pressure (BP) are often regarded as insensitive markers of mild to moderate blood loss. The present study investigated the feasibility of using pulse transit time (PTT) to track variations in pre-ejection period (PEP) during progressive central hypovolaemia induced by head-up tilt and evaluated the potential of PTT as an early non-invasive indicator of blood loss. About 11 healthy subjects underwent graded head-up tilt from 0 to 80 degrees . PTT and PEP were computed from the simultaneous measurement of electrocardiogram (ECG), finger photoplethysmographic pulse oximetry waveform (PPG-POW) and thoracic impedance plethysmogram (IPG). The response of PTT and PEP to tilt was compared with that of interbeat heart interval (RR) and BP. Least-squares linear regression analysis was carried out on an intra-subject basis between PTT and PEP and between various physiological variables and sine of the tilt angle (which is associated with the decrease in central blood volume) and the correlation coefficients (r) were computed. During graded tilt, PEP and PTT were strongly correlated in 10 out of 11 subjects (median r = 0.964) and had strong positive linear correlations with sine of the tilt angle (median r = 0.966 and 0.938 respectively). At a mild hypovolaemic state (20-30 degrees ), there was a significant increase in PTT and PEP compared with baseline (0 degrees ) but without a significant change in RR and BP. Gradient analysis showed that PTT was more responsive to central volume loss than RR during mild hypovolaemia (0-20 degrees ) but not moderate hypovolaemia (50-80 degrees ). PTT may reflect variation in PEP and central blood volume, and is potentially useful for early detection of non-hypotensive progressive central hypovolaemia. Joint interpretation of PTT and RR trends or responses may help to characterize the extent of blood volume loss in critical care patients.

Extreme leukocytosis in the emergency department

Extreme leukocytosis in the absence of haematological disease, is a topic about which little is known, although it may be associated with increased mortality among patients admitted to the intensive care department. The significance of extreme leukocytosis in patients presenting to hospital is uncertain. To study the correlates and prognostic significance of extreme leukocytosis, in patients admitted to an emergency department. Observational study. Consecutive adult patients with extreme leukocytosis (>25 x 10(9)/l, n=54) presenting to the emergency department of a university-affiliated hospital were compared to age-matched controls (+/-5 years) with moderate leukocytosis (12-25 x 10(9)/l, n=118) presenting to the same department. Data were collected on demographic features, emergency room findings and hospital course. Patients with extreme leukocytosis were more likely to suffer from infectious disease (74% vs. 48%, p<0.01), to be hospitalized (100% vs. 80%, p<0.001), and to die (32.1% vs. 12.7%, p<0.01), and had a longer median length of stay (7.5 vs. 4.0 days, p<0.005). There was no significant difference in vital signs between the two groups. In our patients, extreme leukocytosis appeared to be predominantly caused by infectious disease, and was associated with a high case fatality rate. The degree of leukocytosis may provide prognostic information beyond that reflected in traditional vital signs.

221: Impact of the Inclusion of Noninvasive Cardiac Output as a Vital Sign on Medical Decisionmaking in the Emergency Department

Adequate resuscitation of acutely ill patients requires knowledge of the circulatory condition. Traditional vital signs have been shown to be of limited value in the hemodynamic differentiation of patient presenting to the emergency department (ED). In this study we examine the impact on medical decisionmaking of adding noninvasive measures of cardiac output (NICO) by impedance cardiography (ICG) to the available vital signs in a population of ED patients.

The ability of traditional vital signs and shock index to identify ruptured ectopic pregnancy

Objective This study evaluated the correlation between vital signs and hemoperitoneum and the association between abnormal vital signs and tubal rupture. Study design With the use of a retrospective case-control design, the initial heart rate, systolic blood pressure, and heart rate/systolic blood pressure were correlated with respect to degree of hemoperitoneum; predictive values were calculated. Results Fifty-two patients were studied (25 ruptured pregnancies and 27 unruptured ectopic pregnancies). Correlation coefficients were heart rate ( r = 0.50; 95% CI, 0.26-0.68), systolic blood pressure ( r = −0.34; 95% CI, −0.56 to −0.08), and heart rate/systolic blood pressure ( r = 0.69; 95% CI, 0.51-0.81). The sensitivity for heart rate, systolic blood pressure, and heart rate/systolic blood pressure was 28%, 36%, and 72% respectively; the specificity was 96%, 96%, and 67%, respectively. Conclusion Normal vital signs alone are poor predictors of ruptured ectopic pregnancy; the heart rate/systolic blood pressure correlates best with the quantity of intraperitoneal hemorrhage.

Burn injuries

To summarize new advances and research findings that relate to the treatment of burn victims. Recent advances in burn resuscitation and critical care reflect a better understanding of the acute phase pathophysiology of severe burns. Aggressive management of the unstable burn airway is always the most important clinical priority. Emphasis has been placed on the early identification of inhalation injury and its impact on fluid resuscitation, as well as on a protective lung strategy to reduce the development of pulmonary edema, acute lung injury and pneumonia, and to reduce the risk of barotrauma. New blood markers, such as serum cholinesterase and inflammatory cytokines, have been introduced to assist in the prognosis of morbidity and mortality, beyond the traditional vital signs. At this time, however, these are available only for research purposes. Finally, early burn wound excision and coverage with new biodegradable materials results in less pain and more rapid healing for the patient. The combination of innovative approaches and a dedicated burn team is expected to continue to improve survival in the next few years even in the most severe cases.

Assessment of Stroke Index Using Impedance Cardiography: Comparison with Traditional Vital Signs for Detection of Moderate Acute Blood Loss in Healthy Volunteers

Abstract Objectives: Impedance cardiography has been used to detect early hemorrhagic shock, but, to the best of the authors' knowledge, no previous study has looked at the test characteristics of bioimpedance‐derived hemodynamic parameters for the detection of a measured loss of blood volume. The authors set out to investigate the effect of controlled hemorrhage on stroke index (SI) using impedance cardiography, and to evaluate the performance of this test for moderate blood loss in comparison with the performance of traditional vital signs. Methods: Supine and standing measurements of SI were made using a thoracic electrical bioimpedance monitor in 197 healthy, adult volunteers before and after donation of a standard unit (500 mL) of whole blood. Pre‐ and post‐donation means for supine SI, heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP), and for the postural changes in each of these measurements (▵SI, ▵HR, ▵SBP, ▵DBP), were compared using a paired‐sample, two‐tailed t‐test. For each term, receiver operating characteristic (ROC) curves were generated, treating pre‐ and post‐donation populations as independent. Areas under the ROC curves were compared using a method for correlated test result data. Results: Mean ± SD pre‐ and post‐donation values for SI were 47.0 ± 6.9 mL/m2 and 43.9 ± 7.3 mL/m2, respectively (p &lt; 0.0001). Mean pre‐ and post‐donation values for ▵SI were ‐7.7 ± 5.8 mL/m2 and ‐9.0 ± 8.2 mL/m2, respectively (p = 0.02). For discriminating between pre‐ and post‐donation status, the areas under the ROC curves for SI and ▵SI were 0.62 and 0.58, respectively. In comparison, the areas under the ROC curves for HR, SBP, DBP, ▵HR, ▵SBP, and ▵DBP were 0.49, 0.61, 0.56, 0.82, 0.53, and 0.50, respectively. The area under the ROC curve for ▵HR was significantly greater than the area under any of the other curves (p &lt; 0.0001). Conclusions: Moderate blood loss was associated with a decline in mean SI that was clearly detectable with impedance cardiography. However, as a test for moderate blood loss in this controlled setting, neither SI nor ▵SI performed better than traditional vital signs.

The effect of a dissociative dose of ketamine on the bispectral index (BIS) during propofol hypnosis

Study Objective: To compare the effect of a standardized stimulus during propofol-only hypnosis on the bispectral index (BIS) value with the effect of the injection of local anesthesia for surgery during ketamine plus propofol hypnosis (dissociative monitored anesthesia care). To determine whether ketamine increases the level of propofol hypnosis when used in dissociative doses. Design: Descriptive case study. Setting: Private practice office plastic surgery suites. Patients: 30 nonpremedicated ASA physical status I and II adult female (23) and male (7) patients scheduled for elective cosmetic surgery. Interventions: Hypnosis was induced via slow (60 to 80 drops [gtts]/min), dilute (5 mg/ml) propofol solution. Hypnosis was induced using the BIS monitor as an adjunct to traditional vital signs and verbal contact. Patients were engaged in conversation and note was taken of the BIS value when verbal contact was lost and when BIS appeared to stabilize (BIS 1). A standardized stimulus (0.3 ml 1% lidocaine plain via 30-gauge needle) was applied to the area of the supraorbital nerve. Note was taken of the highest BIS value (BIS 2) in the patient response. The BIS returned to baseline hypnosis (BIS 1) and a 50-mg dissociative dose (independent of body weight) of ketamine was administered. Two minutes were allowed to elapse and then the surgeon was allowed to inject the local anesthesia for the proposed surgery. Note was taken of the BIS value (BIS 3) in response to the surgeon’s injection. Measurements and Main Results: The average delta (BIS 2 − BIS 1) was 9.5 ± 6.9. Patients did not move in response to the surgeon’s injection: BIS 3 = BIS 1. When movement occurred, the injection was terminated and additional ketamine was given before resuming the injection. Sixteen patients received ketamine 50 mg, 12 received ketamine 100 mg, one received ketamine 150 mg, and one received ketamine 200 mg. Men required an average 19% less propofol than women in this group. Conclusion: This study demonstrated a positive BIS response to a standardized local anesthetic stimulus during propofol-only hypnosis and a zero response during ketamine plus propofol hypnosis (dissociative anesthesia). Ketamine administered in dissociative doses does not deepen the level of propofol hypnosis. Hypnosis alone does not imply general anesthesia. Patients move in response to inadequate local anesthesia. Because the ketamine analgesia is only transitory and the primary analgesia is not given intravenously, propofol-ketamine technique is not a total intravenous anesthetic technique (TIVA). Instead, propofol-ketamine technique may be classified as a form of monitored anesthesia care (MAC).

Smoking Status as the New Vital Sign: Effect on Assessment and Intervention in Patients Who Smoke

To assess the effect of expanding the vital signs to include smoking status. We prospectively conducted exit interviews with patients at a general internal medicine clinic in Madison, Wisconsin, during a 16-month period from 1991 to 1993. Patients were surveyed briefly before (N = 870) and after (N = 994) the implementation of a simple institutional change in clinical practice. This change involved training the staff in how to use progress notepaper with a vital sign stamp that included smoking status (current, former, or never) along with the traditional vital signs. Included in the survey were questions about whether the patient smoked, whether the patient was asked that day about smoking status (by a clinician or other staff), and, for smokers, whether they were urged to quit smoking and given specific advice on how to do so. After expansion of the vital signs, patients were much more likely to report inquiries about their smoking status on the day of a clinic visit (an increase from approximately 58% at baseline to 81% at intervention; P < 0.0001). The vital sign intervention was associated with significant increases in the percentage of smokers who reported that their clinician advised them that day to quit smoking (from approximately 49% at baseline to 70% during the intervention; P < 0.01) and in the percentage who reported that their clinician gave them specific advice that day on how to stop smoking (from approximately 24% at baseline to 43% during the intervention; P < 0.01). Expanding the vital signs to include smoking status was associated with a dramatic increase in the rate of identifying patients who smoke and of intervening to encourage and assist with smoking cessation. This simple, low-cost intervention may effectively prompt clinicians to inquire about use of tobacco and offer recommendations to smokers.