Short Term Midline vs. PICC
Safety and Outcomes of Midline Catheters vs Peripherally Inserted Central Catheters for Patients With Short-term Indications: A Multicenter Study.
Swaminathan L, Flanders S, Horowitz J, Zhang Q, O’Malley M, Chopra V.
JAMA Intern Med. 2022 Jan 1;182(1):50-58. [Full text]
Peripherally inserted central catheters (PICCs) are inserted into peripheral veins with the tip ending near the cavoatrial junction (CAJ). That the catheter ends in a larger, great vessel is theoretically thought to reduce thrombosis risk. Midline catheters in comparison are inserted in peripheral veins and terminate at or below the axillary vein (in the brachial, basilic, or cephalic veins), distal to the shoulder. Many believe infections are lower in catheters that terminate much more proximal than a central catheter. Whether one is more safe or associated with complications such as thrombosis is unclear, with conflicting results coming from retrospective reviews [1, 2]. Because of this uncertainty, the authors of this study decided to evaluate a multihospital quality improvement registry to compare outcomes in patients who received PICCs to those who received midlines for short term indications.
Patient population and Design
Between December 2017 and January 2020 there were 5758 patients with PICCs and 5105 with midlines that were placed for the indications of difficult venous access or short-term (≤30 days) intravenous (IV) antibiotics. Those that were younger than 18, pregnant, not on a medical service or admitted under observation status were excluded. Patient demographic and data were extracted including device variables, including the number of insertion attempts, placement arm and vein of insertion, catheter gauge, and number of catheter lumens.
Outcomes
Complications were an outcome defined as the composite of symptomatic upper extremity DVT or pulmonary embolism (PE), central line–associated bloodstream infection (CLABSI) in the case of PICCs or catheter-related bloodstream infection (CRBSI), in the case of midlines, and catheter occlusion.
Of note, the distinction between a CLABSI and CRBSI is generally a clinical one, somewhat in contrast to how it is handled in this study. Generally a CRBSI is when the infection is more directly tied to the presence of a catheter rather than just associated with it. In this article, a CLABSI associated with a PICC was defined as a positive blood culture with the PICC in place for at least 48 hours, without or longer without another identified infection source, if the PICC tip culture was positive in the setting of clinically suspected catheter infection, or if documentation of bacteremia, sepsis, or CLABSI due to the PICC was found in the medical record. CRBSI here required the physician to document the bloodstream infection or line sepsis or line bacteremia associated with the midline, the midline was removed specifically for suspected infection, or no other source was identified.
Results
When reviewed, the PICC and midline patients had similar comorbidity burden (median Charlson score = 3 for both). In terms of indications, more midlines were inserted for the indication of difficult IV access than PICCs (72.4% vs 40.1%), while more PICCs were placed for the indication for short-term IV antibiotics (72.4% vs 40.1%). The median dwell time for PICCs was longer, 14 (7-27) days vs 6 (3-12) days for midlines.
Overall, 9.9% (n = 569) of patients with a PICC vs 3.9% (n = 200) of patients with a midline experienced a major complication, and when adjusted for comorbidities the risk of any complication was nearly double for PICCs (OR, 1.99; 95% CI, 1.61-2.47). The most prevalent of which was catheter occlusion, 7.0% (405) PICCs vs. 2.1% (105) midlines, adjusted OR, 2.24 (95% CI, 1.70-2.96). CLABSI in PICCs was more common than CRBSI in midlines, 1.6% vs. 0.4%, though both were generally rare, the adjusted risk was significant, OR 4.44 (95% CI, 2.52-7.82). DVT occurred with similar frequency in each, 1.5% PICC vs. 1.4% midlines (adjusted OR, 0.93; 95% CI, 0.63-1.37).
Since the dwell time of a PICC in the cohort was longer, a Cox proportional hazard model to adjust for that time was fitted to the data. The results for occlusion and infection were similar to above, favoring midlines. There was, however, a lower hazard of DVTs for PICCs vs midlines (HR, 0.53; 95% CI, 0.38-0.74) when accounting for this dwell time.
Discussion
This observational cohort found that all complications and particularly catheter occlusion and infection were less common in midlines for patients with an indication for a short-term midline or PICC. The Michigan Appropriateness Guide for Intravenous Catheters (MAGIC) recommends midlines in patients with difficult vascular access if treatment will likely exceed 6 days, and for infusions up to 14 days [3]. This practice is far from universal but the findings of this study, which seems to favor midlines in regard to occlusion and infection risk supports that recommendation. Of note, the DVT risk seems actually lower with PICCs, but may be related to the dwell time of the catheter, which could be potentially mitigated by shorter use.
The observational nature of this study leads to some obvious limitations, but at least patients have a similar degree of co-morbidity. But there was a major difference in patient selection, with those with difficult access more likely receiving a midline and long term antibiotics receiving a PICC. As the patients in this cohort with infections are more likely to to receive a PICC, it is at least possible that the same cohort would be more at risk for subsequent infection, i.e. CLABSI/CRBSI.
Also, the choice to compare CLABSI for PICC and CRBSI for midlines may have skewed the infection risk. CLABSI is generally thought to be an association, while a CRBSI clinically ties the catheter as the source of the infection. This could potentially inflate the PICC infection risk as potentially some of the associated infections were not truly as a result of the PICC line itself.
Catheter occlusion was considered a significant complication, but at least for a PICC this can be remedied with alteplase on many occasions. In fact, in this study, midlines were removed more often than PICCs owing to complications, speaking potentially to the fact that some complications can be managed without interrupting use.
In the end, because of this study, midlines should be at least considered when appropriate for short term use which is in congruence with MAGIC recommendations [3]. Patients should know that there is a potential small risk of infection with either type of catheter, and PICCs may have more risk than midlines. But similarly, PICCs may have less DVT risk than midlines, which should also be considered. A prospective randomized trial would be needed to make stronger recommendations favoring one catheter over another for short term use.
| F: Follow up | 30 days |
| R: Randomization | No, cohort |
| I: Intention to treat | N/A |
| S: Similar at baseline | Similar comorbidity index |
| B: Blinding | N/A |
| E: Equal treatment | N/A |
| S: Source (funding) | BCBSM and Blue Care Network as part of the BCBSM Value Partnerships program |
- Bahl A, Karabon P, Chu D. Comparison of Venous Thrombosis Complications in Midlines Versus Peripherally Inserted Central Catheters: Are Midlines the Safer Option? Clin Appl Thromb Hemost. 2019 Jan-Dec;25:1076029619839150.
- Hogle NJ, Balzer KM, Ross BG, et al. A comparison of the incidence of midline catheter-associated bloodstream infections to that of central line-associated bloodstream infections in 5 acute care hospitals. Am J Infect Control. 2020 Sep;48(9):1108-1110.
- Chopra V, Flanders SA, Saint S, et al.; Michigan Appropriateness Guide for Intravenouse Catheters (MAGIC) Panel. The Michigan Appropriateness Guide for Intravenous Catheters (MAGIC): Results From a Multispecialty Panel Using the RAND/UCLA Appropriateness Method. Ann Intern Med. 2015 Sep 15;163(6 Suppl):S1-40.
