Is Peripheral Line Placement More Difficult in Obese Than in Lean Patients?

Insertion of a peripheral venous line is classically more difficult in obese patients (1,2). Thus, routine central venous access has been recommended for the perioperative management of these patients (3) despite the significant morbidity associated with its use (4). However, these assumptions have never been validated. We conducted a study to determine whether peripheral venous line insertion is more difficult in obese than in lean patients. Patients and Methods After IRB approval and informed patient consent, the ease of peripheral venous line insertion was prospectively compared in consecutive obese and lean patients scheduled for routine surgery. Exclusion criteria were shock, rheumatoid arthritis, IV infusion within the last 7 days, pregnancy, and history of chemotherapy or drug abuse. In the operating room, a tourniquet was placed, and insertion of an 18-gauge Protectiv® catheter into a peripheral vein (right or left upper limb) was attempted by a certified anesthesiologist or a certified nurse anesthetist with 2 yr or more experience. The ease of insertion was evaluated using a scale based on several variables: N1, the number of additional tourniquet placements; N2, the number of additional skin punctures; N3, the number of additional operators; N4, the number of additional puncture sites (right or left upper or lower limb and right or left external jugular vein); and N5, the number of additional catheters used. The venous line insertion score was the sum of N1 through N5. It yielded a score that could range from 0 (easy insertion) to infinity, with larger scores indicating more difficult insertion. A score of 0 indicates venous access performed on the first attempt by the first operator. A score of more than 0 indicates moderate to major difficulty. The need for central venous line insertion was recorded. Results were expressed as mean ± sd. The χ2 test with Yates correction was used for between-group comparisons. P < 0.05 was significant. Results Thirty-one lean (nine women, 50 ± 18 yr; 70 ± 12 kg; 172 ± 9 cm; body mass index, 23 ± 3 kg/m2) and 25 morbidly obese consecutive patients (16 women, 44 ± 11 yr; 126 ± 30 kg; 166 ± 8 cm; body mass index, 46 ± 12 kg/m2) were studied. Peripheral line placement was consistently successful in all patients. Central venous line insertion was not required in any patient. The line insertion score was 0 for 27 (87%) lean patients and 16 (64%) obese patients (P < 0.05). The highest score value was 5 in the lean group and 9 in the obese group (P < 0.05). Discussion This finding confirms that peripheral venous line insertion is more difficult in obese than in lean patients. Despite the limitations of this report (e.g., small sample size and lack of validation of the method used to compare the ease of peripheral line insertion), the observation that peripheral line placement was always successful also clearly demonstrates that the recommendation that a central venous line should be inserted routinely in obese patients is not valid (3). The difficulty of peripheral line insertion in obese patients emphasizes the importance of preserving the venous stock in such patients in anticipation of the potential demands of postoperative care (e.g., enteral nutrition or IV treatments).