Perioperative arterial catheterization: A prospective evaluation of ultrasound, infection, and patient-focused outcomes

BACKGROUND

There is little information regarding complications of arterial catheterization in modern clinical care. We aimed to determine the incidence of abnormal duplex vascular ultrasound and catheter related infections following perioperative arterial catheterization.

METHODS

Patients requiring arterial catheterization for elective surgery were included and insertion details collected prospectively. Duplex ultrasound evaluation was performed 24 h after catheter removal. Symptomatic patients were identified by self-reported questionnaire. On Day 7, patients answered questions by telephone, related to the insertion site, pain, and function. Results of catheter tip and blood culture analyses were sought. Univariate associations of patient and surgical characteristics with abnormal ultrasound were assessed with p < 0.05 considered significant.

RESULTS

Of 339 catheterizations, 105 (40%) had ultrasound evaluation. Catheters were indwelling for median (IQR, range) duration of 6.0 h (4.4-8.2, 1.8-28) with no catheter-related infections. There were 16 (15.2%, 95% CI 9.0%-23.6%) abnormal results, including 14 radial artery thromboses, one radial artery dissection, and one radial vein thrombosis. Those with abnormal ultrasound results were more likely to have had Arrow catheters inserted (68.8% vs 27%, p = 0.023) and more than one skin puncture (37.5% vs 26.8%, p = 0.031). Two of the 16 (12.5%) patients with abnormal ultrasound results reported new symptoms related to the hand compared with nine of the 88 (10.2%) with normal results (p = 0.1). No patients required urgent referral for management.

CONCLUSIONS

Thrombosis was the most common abnormality and was usually asymptomatic. There were no infections, few post-operative symptoms, and minimal functional impairment following arterial catheterization.

Clinical Utility of Arterial Blood Gas Test in an Intensive Care Unit: An Observational Study

Background

Arterial blood gas (ABG) analysis is a common test ordered in critically ill patients. Often, it is performed very frequently without influencing patient care. Hence, we decided to check the utility of the ABG test in our intensive care unit (ICU).

Materials and methods

The data of the previous day ABGs were captured by reviewing the chart in an online pro forma which was filled by the authors. Data relating to patient's details, who ordered ABGs, reason for ordering ABGs, and did the ABG influence patient's management were entered. A total of 985 ABGs were performed in 173 patients for 2 months which was analyzed.

Results

Out of 985 ABGs, in 259 instances (26.29%), interventions were done after reviewing an ABG. The major interventions among these ABGs were ventilator settings adjustment in 134 ABGs (13.6%). A total of 790 ABGs were done routinely with no specific indication (80.20%), while doctors ordered one following an event for 195 ABGs (19.80%).

Conclusion

Our data suggest that 80% of ABG tests were ordered as part of a routine test.

How to cite this article

Chandran J, D'Silva C, Sriram S, Krishna B. Clinical Utility of Arterial Blood Gas Test in an Intensive Care Unit: An Observational Study. Indian J Crit Care Med 2021;25(2):172–175.

Evaluation of Two Femoral Arterial Cannulae With Conventional Non-Pulsatile and Alternative Pulsatile Flow in a Simulated Adult ECLS Circuit

The objective of this study is to evaluate the hemodynamic characteristics of two femoral arterial cannulae in terms of circuit pressure, pressure drop, and hemodynamic energy transmission under non-pulsatile and pulsatile modes in a simulated adult extracorporeal life support (ECLS) system. The ECLS circuit consisted of i-cor diagonal pump and console (Xenios AG, Heilbronn, Germany), an iLA membrane ventilator (Xenios AG), an 18 Fr or 16 Fr femoral arterial cannula (Xenios AG), and a 23/25 Fr Estech remote access perfusion (RAP) femoral venous cannula (San Ramon, CA, USA). The circuit was primed with lactated Ringer's solution and packed red blood cells to achieve a hematocrit of 35%. All trials were conducted at room temperature with flow rates of 1-4 L/min (1 L/min increments). The pulsatile flow settings were set at pulsatile frequency of 75 bpm and pulsatile amplitudes of 1000-4000 rpm (1000 rpm increments). Flow and pressure data were collected using a custom data acquisition system. Total hemodynamic energy (THE) is calculated by multiplying the ratio between the area under the hemodynamic power curve (∫flow × pressure dt) and the area under the pump flow curve (∫flow dt) by 1332. The pressure drop across the arterial cannula increased with increasing flow rate and decreasing cannula size. The pressure drops of 18 Fr and 16 Fr cannulae were 19.4-24.5 and 38.4-45.3 mm Hg at 1 L/min, 55.2-56.8 and 110.9-118.3 mm Hg at 2 L/min, 94.1-105.1 and 209.7-215.1 mm Hg at 3 L/min, and 169.2-172.6 and 376.4 mm Hg at 4 L/min, respectively. Pulsatile flow created more hemodynamic energy than non-pulsatile flow, especially at lower flow rates. The percentages of THE loss across 18 Fr and 16 Fr cannula were 16.0-18.7 and 27.5-30.8% at 1 L/min, 35.1-35.7 and 52.3-53.8% at 2 L/min, 48.3-50.3 and 67.3-68.4% at 3 L/min and 62.9-63.1 and 79.0% at 4 L/min. The hemodynamic performance of the arterial cannula should be evaluated before use in clinical practice. The pressure drops and percentages of THE loss across two cannulae tested using human blood were higher compared to the manufacturer's data tested using water. The cannula size should be chosen to match the expected flow rate. In addition, this novel i-cor ECLS system can provide non-pulsatile and ECG-synchronized pulsatile flow without significantly increasing the cannula pressure drop and hemodynamic energy loss.