Dorsalis pedis cannulation: An overlooked option—A case report

Introduction

The direct measurement of arterial blood pressure by an intraarterial catheter is commonly used in anesthesiology. Invasive arterial monitoring gives accurate blood pressures, ability to measure cardiac output, and frequent blood gas measurement. Hence, it can guide in fluid resuscitation. ¹

The common sites for arterial cannula placement are the radial, brachial, and femoral arteries. ²

The most favored artery for cannulation is the radial artery. The most important reason for radial artery selection is its location, the collateral circulation, and a low complication rate. ³ A case of difficult invasive cannulation in an elective surgical procedure is being reported here.

Case report

A 45-year-old female with no known comorbidities was planned for supratentorial craniotomy secondary to meningioma. After applying standard American Society of Anaesthesiology (ASA) monitoring, the patient was induced and intubated successfully. Invasive central venous pressure and intraarterial pressure monitoring were planned. Despite multiple ultrasound-guided attempts on radial, ulnar, brachial, and femoral arteries by five different consultant anesthesiologists, no one was able to get arterial access. Femoral vein was attempted for central venous access but was also not successful. After a discussion with the neurosurgeon, surgery was abandoned, and the patient awakened. This surgery was replanned after 2 days with a new anesthesia team, who attempted the dorsalis pedis artery for arterial cannulation and the internal jugular vein for central venous access. Both cannulations were done successfully on the first attempt, and surgery proceeded without any complications.

Discussion

The significance of intraarterial blood pressure measurement, especially in the setting of neurosurgical procedures cannot be over-emphasized. The continuous monitoring of blood pressure results in timely intervention as the sudden changes in patient’s condition can be easily picked up.

The radial artery is easily accessible as it is superficially located and has a low complication rate. ⁴ Despite these advantages, sometimes it is difficult to cannulate radial arteries due to anatomical deformities, upper extremity burns, and trauma.

The foot is mainly supplied by the posterior tibial and dorsalis pedis arteries. ⁵ These arteries can be considered alternatives to radial arteries for cannulation. The dorsalis pedis artery is the direct continuation of anterior tibial artery in front of the ankle joint. It passes midway between the medial and lateral malleoli till the proximal end of the first dorsal intermetatarsal space from where it continues inferiorly as deep plantar artery. ⁶

The dorsalis pedis artery is congenitally absent in around 3% of the population. ⁷ In the other 97% of individuals, the flow of the dorsalis pedis artery is excellent. It can be easily cannulated with the same risk of complications as that of posterior tibial artery.^8,9 However, it should be noted that the systolic pressure readings are 5–20 mmHg higher than those taken at the radial artery. ¹⁰

In a few cases, foot gangrene has been reported due to dorsalis pedis artery cannulation. ¹¹ The risk can be minimized by simulated training, knowing the anatomy, and adopting strict aseptic measures. It is imperative to monitor the site regularly for any bleeding and inflammation to minimize complications and remove the lines as soon as possible. There may be significant risks involved with repeated arterial cannulations, including vessel thrombosis, limb ischemia and, rarely, loss of the limb. ¹² Our patient was followed daily for a week, and there were no complications noted.

Distal radial artery cannulation is another evolving alternative site for blood pressure monitoring because it is relatively superficial at the anatomical snuffbox and receives collateral circulation from the superficial palmar branch and the ulnar artery. Due to its anatomy, it is considered to maintain the integrity of the forearm radial artery. ¹³

In our case, multiple attempts were made in the radial, brachial, femoral, and ulnar arteries, while the dorsal pedis approach was not considered. As anesthetists, we must be familiar with the dorsal pedis and new evolving approaches like distal radial arterial cannulation approach because it may be a reasonable, practical, and safe approach.

Conclusion

In summary, dorsalis pedis artery can be an option for arterial cannulation when radial artery cannulation is not possible. However, it must be kept in mind that the systolic pressures measured at dorsalis pedis are higher than at the radial artery whereas the mean arterial pressures are not clinically significant.