Reducing amount of contrast agent after compression of right brachial artery using a blood pressure cuff in computed tomography cerebrovascular angiography

OBJECTIVE

To invastgate feasibility of low-dose contrast agent in cerebral computed tomography angiography (CTA) to alleviate side effects.

METHOD

Siemens' Somatom Definition AS+CT scanner, Heine's blood pressure monitor G7-M237 (BP cuff) and Ultravist contrast agent (370 mg Iodine/ml) are used. CTA is acquired using following scan parameters including slice thickness of 1mm, image acquisition parameters of 128×0.6 mm, pitch size of 0.8 mm, 175 effective mAs, 120 kVp tube voltage, scan delay time of 3 seconds, and the scan time of 4 seconds. This study is conducted by securing the IV route in the left antecubital vein before injection of contrast agent, wrapping BP cuff around the branchial artery of the opposite right arm after setting the pressure to 200 mmHg. Then, the injection rate of the contrast agent is fixed at 4.5 cc/sec and contrast agent was injected in three different amounts (70, 80, and 100 cc). Bp cuff is released from this moment when HU value reachs 100.

RESULT

In this study, the mean HU values measured from common carotid artery are 412.45±5.89 when injecting 80cc contrast agent and using BP cuff and 399.64±5.51 when injecting 100 cc contrast agenet and not using BP cuff, respectively. In middle cerebral artery M1, the mean HU values are 325.23±38.29 when injecting 80cc contrast agent and using BP cuff and 325.00±30.63 when injecting 100cc contrast agent blood and not using pressure cuff, respectively. Difference of mean HU values is not statistically significant (p > 0.05) with and without using BP cuff.

CONCLUSION

This study demonstrates that reducing amount of contrast agent is possible when the right brachial artery is compressed using BP cuff. Study results indicate that reducing 20% injection of contrast agent in CT cerebrovascular angiography can still yield comparable imaging results with conventional contrast angent usage, which implies that less side effects are expected with a contrast agent injection. Thus, this study can serve as a reference for potential reducing side effect during CT cerebrovascular angiography.

Modulation of Pulse Propagation and Blood Flow via Cuff Inflation-New Distal Insights

In standard critical care practice, cuff sphygmomanometry is widely used for intermittent blood pressure (BP) measurements. However, cuff devices offer ample possibility of modulating blood flow and pulse propagation along the artery. We explore underutilized arrangements of sensors involving cuff devices which could be of use in critical care to reveal additional information on compensatory mechanisms. In our previous work, we analyzed the response of the vasculature to occlusion perturbations by means of observations obtained non-invasively. In this study, our aim is to (1) acquire additional insights by means of invasive measurements and (2) based on these insights, further develop cuff-based measurement strategies. Invasive BP experimental data is collected downstream from the cuff in two patients monitored in the OR. It is found that highly dynamic processes occur in the distal arm during cuff inflation. Mean arterial pressure increases in the distal artery by 20 mmHg, leading to a decrease in pulse transit time by 20 ms. Previous characterizations neglected such distal vasculature effects. A model is developed to reproduce the observed behaviors and to provide a possible explanation of the factors that influence the distal arm mechanisms. We apply the new findings to further develop measurement strategies aimed at acquiring information on pulse arrival time vs. BP calibration, artery compliance, peripheral resistance, artery-vein interaction.

Evaluation of pain susceptibility by taking blood pressure in patients with infections: A prospective comparative study

Pain sensitization leading to polyalgia can be observed during infectious diseases. The blood pressure cuff-evoked pain threshold (BPCEPT) has been used in previous studies as a screening tool for fibromyalgia.We aimed to use the BPCEPT as a screening test for detecting pain sensitization in patients suffering from infectious diseases. We also investigated whether specific factors were associated with pain sensitization.We performed a prospective comparative study including all patients of our infectious diseases center in a 1-year period. We created a positive control group of patients suffering from fibromyalgia and a negative control group of "apparently healthy" patients consulting for vaccination.The blood pressure (BP) cuff was inflated until the patient signaled that they experienced pain, and this pressure value was noted.A total of 2355 patients were included. The positive control group had significantly lower values of the BPCEPT than all other groups. Among hospitalized patients with infectious diseases, a low BPCEPT was significantly associated with high temperature (P < .0001), older age (P = .002), being a woman (P = .004), high serum glutamic-oxaloacetic transaminase (P = .007), and high C reactive protein levels (P = .02). Moreover, in multivariate analysis, respiratory infection, meningitis, urinary tract infection, febrile neutropenia, and Q fever were independently associated with a low BPCEPT. A significant negative dynamic correlation between the BPCEPT and temperature was also observed (P < .001).We demonstrated for the first time in a large sample of patients that the BPCEPT method can be used to detect pain susceptibility. We observed a significant dynamic correlation between pain sensitization and temperature. Additionally, pain sensitization was associated with some diseases, suggesting that they trigger pain sensitivity.

Perioperative Considerations in Osteogenesis Imperfecta: A 20-Year Experience with the Use of Blood Pressure Cuffs, Arterial Lines, and Tourniquets

Osteogenesis imperfecta (OI) is a rare genetic connective-tissue disorder with bone fragility. To avoid iatrogenic fractures, healthcare providers have traditionally avoided using non-invasive blood pressure (NIBP) cuffs and extremity tourniquets in the OI population in the perioperative setting. Here, we hypothesize that these procedures do not lead to iatrogenic fractures or other complications in patients with OI. A retrospective study of all children with OI who underwent surgery at a single tertiary care children’s hospital from 1998 to 2018 was performed. Patient positioning and the use of NIBP cuffs, arterial lines, and extremity tourniquets were documented. Fractures and other complications were recorded. Forty-nine patients with a median age of 7.9 years (range: 0.2–17.7) were identified. These patients underwent 273 procedures, of which 229 were orthopaedic operations. A total of 246 (90.1%) procedures included the use of an NIBP cuff, 61 (22.3%) an extremity tourniquet, and 40 (14.7%) an arterial line. Pediatric patients with OI did not experience any iatrogenic fractures related to hemodynamic monitoring or extremity tourniquet use during the 20-year period of this study. Given the benefits of continuous intra-operative hemodynamic monitoring and extremity tourniquets, we recommend that NIBP cuffs, arterial lines, and tourniquets be selectively considered for use in children with OI.

Efficacy of an Ethanol-Based Hand Sanitizer for the Disinfection of Blood Pressure Cuffs

Blood pressure cuffs (BP cuffs) have been implicated in some nosocomial outbreaks. We compared the efficacy of an ethanol-based hand sanitizer (EBHS) with a detergent/disinfectant for the disinfection of BP cuffs. The inner sides of 30 BP cuffs were sampled for bacterial culture. Then, the same area was divided into halves. One half was disinfected by a detergent/disinfectant and the other was disinfected by an EBHS. The bacterial count decreased significantly with both disinfectants (p < 0.0001 compared with before disinfection). The bacterial count decrease seemed greater with the EBHS compared with the detergent/disinfectant, but the difference was not significant. Therefore, within the limits of a single application, the EBHS was an efficacious means of BP cuff disinfection. However, the repeated exposure to emollients contained in EBHS may require further studies before validating these results.

Comparison of blood pressure measurements in the upper and lower extremities versus arterial blood pressure readings in children under general anesthesia

Purpose

To compare invasive blood pressure (IBP) readings obtained from an arterial cannula with non-invasive blood pressure (NIBP) measurements from oscillometric cuffs on the upper and lower extremities of infants and children under general anesthesia.

Patients and methods

Patients under 10 years of age were enrolled in our study if they were to receive general anesthesia with planned placement of a radial arterial cannula. At 5 mins intervals, IBP was measured using a fluid-coupled pressure transducer and NIBP was measured with two oscillometers with appropriately sized cuffs placed on the upper arm and lower leg, for 10 readings per patient.

Results

The study enrolled 18 boys and 12 girls, ranging in age from 0 to 8 years. Across 300 data points, the absolute difference between the arm and invasive mean arterial pressure (MAP) measurements was 7±7 mmHg (range: 0–52 mmHg). The absolute difference between the leg and invasive MAP measurements was 8±8 mmHg (range: 0–52 mmHg). Although both non-invasive measurement sites demonstrated frequent deviation from invasive measurement, large deviations were more common when BP was measured at the leg (81 of 298 observations (27%) deviating by >10 mmHg) compared to the arm (60 of 300 observations (20%) deviating by >10 mmHg).

Conclusion

The frequency of clinically significant NIBP deviation in children under general anesthesia supports the importance of IBP monitoring when hemodynamic fluctuations are likely and would be particularly detrimental. NIBP measured at the lower leg is more likely to result in clinically significant deviation from invasively measured MAP than NIBP values obtained from an upper arm.

Equivalence between invasive and oscillometric blood pressures at different anatomic locations in healthy normotensive anaesthetised horses

REASONS FOR PERFORMING STUDY

Accurate blood pressure measurement is essential for effective clinical assessment and appropriate interventions in anaesthetised horses. Information on the accuracy of oscillometry for blood pressure measurement on the appendages of mature horses is limited.

OBJECTIVES

To assess equivalence between invasive and oscillometric blood pressures at different anatomic locations in horses.

STUDY DESIGN

Prospective experimental study using 6 healthy mature horses.

METHODS

Blood pressure was measured invasively in the right transverse facial artery and noninvasively by oscillometry in nondependent limbs and tail of laterally recumbent sevoflurane- or desflurane-anaesthetised horses. Cuff widths of 5-12 cm were tested on the tail, metatarsus, metacarpus and distal radius/ulna. Equivalence between mean arterial pressure (MAP) oscillometric and MAP invasive was assessed using a linear mixed effects model with a significance level of P≤0.05.

RESULTS

Twenty paired measurements were obtained for each cuff size in each of the locations, totalling 340 measurements. There was only one location (tail) and one cuff width (6 cm; cuff width-to-tail circumference ratio of 0.25) that resulted in equivalence between MAP measured with the oscillometric and the invasive methods (P = 0.8). All other locations (metacarpus, radius/ulna, metatarsus) and cuff widths were not equivalent (P≤0.01).

CONCLUSIONS

A cuff width-to-tail circumference ratio of 0.25 is recommended for accurate oscillometric blood pressure measurement in mature, laterally recumbent anaesthetised normotensive horses. Studies with variable haemodynamics are warranted. Oscillometric measurements at other extremities and/or with other cuff sizes cannot be recommended for clinical use.

Preventing the collapse of a peripheral vein during cannulation: an evaluation of various tourniquet techniques on vein compressibility

BACKGROUND

Venous access can occasionally be difficult to obtain secondary to near-complete compressibility of peripheral veins in some patients.

OBJECTIVE

This study utilizes ultrasound to assess vein compressibility with different tourniquet techniques commonly available in the emergency department.

METHODS

After approval by the Institutional Review Board, a prospective single-center study was conducted assessing the compressibility of basilic veins with ultrasound. Compressibility was assessed at baseline, use of one proximal tourniquet, two tourniquets (one distal and one proximal), and a proximal blood pressure cuff inflated to 150 mm Hg. Vein compressibility was rated as complete, moderate, or mild after light pressure was applied with the ultrasound probe.

RESULTS

One hundred healthy patients were recruited into the study. Ninety-eight subjects had completely compressible basilic veins at baseline. When one tourniquet and two tourniquets were applied, 62 and 31 participants, respectively, demonstrated completely compressible veins. Fisher's exact test comparing one vs. two tourniquets revealed no difference between these two techniques (p = 0.4614). Only two participants continued to have a completely compressible vein after application of the blood pressure cuff with statistical significance by Fisher's exact test compared to both tourniquet groups (p < 0.0001).

CONCLUSIONS

Both tourniquets and blood pressure cuffs can decrease the compressibility of peripheral veins. Although no difference was identified between one and two tourniquets, utilization of blood pressure cuffs significantly decreased compressibility. The findings of this study can be utilized in the emergency department when attempting to obtain peripheral venous access, specifically supporting the use of blood pressure cuffs to decrease compressibility.