Small gauge central venous catheters and right atrial catheters

In conclusion, the silastic catheters are viable alternatives to peripheral venous access in patients with impaired peripheral venous integrity secondary to prior chemotherapy, extravasation, circulatory impairment, and/or phlebitis. Careful planning in anticipation of the patient's long-term vascular access needs will enable earlier placement and may reduce complications secondary to chemotherapy administration via impaired peripheral veins.The oncology nurse has a primary role in the assessment of the patient's need for central venous access. Frequency of blood sampling, chemotherapy administration schedules, requirements for blood products and intravenous medications and fluids are all influencing factors. Providing information to the patient and family about the various vascular access devices is an important role of the oncology nurse as well. Assessment of the patient and family member's abilities to care for the catheter, the home environment, and follow-up needed will help plan later care. Early patient and family education, once a vascular access device is selected, will promote patient independence at home. Meticulous catheter care by the oncology nurse when the patient is hospitalized and careful follow-up of the patient's management of the catheter will help ensure the greatest longevity and lessen the incidence of complications. They are, in one patient's words, a “life-line,” and should always be respected. Oncology nurses are in the forefront of role-modeling this respect.     

Risk of colonization of central venous catheters: catheters for total parenteral nutrition vs other catheters.

BACKGROUND: Infected central venous catheters cause morbidity and mortality. OBJECTIVE: To compare the risk for colonization of central venous catheters used for total parenteral nutrition with that of catheters used for other purposes. METHODS: Retrospective review of prospectively acquired data on 260 patients with a stay in a surgical intensive care unit longer than 3 days. Single-lumen catheters used solely for total parenteral nutrition were inserted into the subclavian vein and cared for by a dedicated team. Catheters for other purposes were placed and cared for by other staff. Catheters were cultured if clinical findings suggested infection. RESULTS: Of 854 central venous catheters, 61 (7%) were used for total parenteral nutrition. During 4712 catheter days of observation, 89 catheters of all types were colonized. Risk factors for colonization included duration of catheterization (P < .001), having 3 or more lumens (hazard ratio, 1.7; 95% CI, 1.1-2.6), pulmonary artery catheterization (hazard ratio, 1.7; 95% CI, 1.1-2.7), and placement in the internal jugular vein (hazard ratio, 1.6; 95% CI, 1.1-2.5). Catheters used for total parenteral nutrition (hazard ratio, 0.14; 95% CI, 0.04-0.57) and those in the subclavian vein (hazard ratio, 0.51; 95% CI, 0.3-0.8) were at lower risk of colonization. In a multivariate Cox model, the only significant factor was a 5-fold lower risk of infection for catheters used for total parenteral nutrition (hazard ratio, 0.19; 95% CI, 0.04-0.83). CONCLUSION: Rates of colonization were lowest for catheters used solely for total parenteral nutrition, suggesting that a team approach improves patients' care.     

Indwelling urethral catheters

Lesley Simpson discusses the risks associated with indwelling urethral catheters and identifies how nurses can reduce them with proactive management.     

Standard-length catheters vs long catheters in ultrasound-guided peripheral vein cannulation

Purpose

Ultrasound (US) is a useful tool for peripheral vein cannulation in patients with difficult venous access. However, few data about the survival of US-guided peripheral catheters in acute care setting exist. Some studies showed that the survival rate of standard-length catheters (SC) is poor especially in obese patients. The use of longer than normal catheters could provide a solution to low survival rate. The aim of the present study was to compare US-guided peripheral SCs vs US-guided peripheral long catheters inserted with Seldinger technique (LC) in acute hospitalized patients with difficult venous access.

Methods

This was a prospective, randomized controlled trial. A total of 100 consecutively admitted subjects in an urban High Dependency Unit were randomized to obtain US-guided intravenous access using either SC or LC after 3 failed blind attempts. Primary outcome was catheter failure rate.

Results

Success rate was 86% in the SC groups and 84% in the LC group (P = .77). Time requested to positioning venous access resulted to be shorter for SC as opposed to LC (9.5 vs 16.8 minutes, respectively; P = .001). Catheter failure was observed in 45% of patients in the SC group and in 14% of patients in the LC group (relative risk, 3.2; P < .001).

Conclusions

Both SC and LC US-guided cannulations have a high success rate in patients with difficult venous access. Notwithstanding a higher time to cannulation, LC US-guided procedure is associated with a lower risk of catheter failure compared with SC US-guided procedure.     

Thrombogenicity of pulmonary-artery catheters

The thrombogenicity of heparin-bonded and non-heparin-bonded pulmonary-artery catheters was compared by means of pull-out phlebography in a prospective, randomized clinical study of 20 patients in an intensive care unit (ICU). The duration of catheterization averaged 47.4±4.1 h in the heparin-bonded group (10 patients) and 45.7±7.1 h in the non-heparin-bonded (10 patients). Age, clinical diagnosis, mean time required to obtain a stable wedge position, heparin dose administered and clotting indices were comparable between the groups. There was no statistically significant difference in the length of formed thrombi (2.3±1.89 vs 5.88±4.62 cm) or frequency of thrombus formation between the groups. The thrombi originated and propagated from the puncture site. They were mural proximally and formed sleeves in the superior vena cava. Several sleeves stripped off on withdrawal of the catheter. Protection from thrombosis offered by heparin bonding of pulmonary-artery catheters should, therefore, not be overstimated — at least not in long-therm catheterization of ICU patients.     

Possibilities of ultrasound catheters

Ultrasound catheters offer the possibility of various non-imaging applications. Some of these applications, now in different stages of development, have been studied and will be described here in some detail. Ultrasonically marked catheters have different applications. The catheter has a miniature marker transducer mounted at the tip or some other place of interest. Initially, this device was used to localize the pacing lead tip in the heart. Connected to a transponder of a passive type this device can generate a visible localization mark on the echograph screen. The basically same system can be used for early detection of cracking of the pacing lead insulation. In this case the marker transducer works as a high-frequency signal generator and detects characteristic capacitance changes better than other methods. The electronic circuit for measurement is built into the pacemaker. Other non-imaging applications have also been studied. The marker transducer can be used for echo ranging of the distance between a His bundle fulguration electrode and the structure to be destroyed. Such an automatic ‘proximity fuse’ can help to avoid the firing of energy at too great a distance from the His bundle. Technology of implantable defibrillators yields the possibility for a double transducer arrangement, one transducer mounted at the patch and the other being the marker transducer. Using on-line distance measurement this arrangement enables early detection of abnormal movement of the ventricle wall, thus detecting deterioration of the muscle function before it is electrically evident. The measurement was simulatedin-vitro. Measurement of axial blood flow using transit time methods, instead of Doppler, was also experimentally studied. The transit time method consists of measurement of the autocorrelation function of signals reflected from a perpendicular flow and gives a genuine measurement orthogonal to the Doppler method. Some of the feasibility studies will be discussed. Moreover, a waveguide catheter for uretral stone lithotripsy is reported which also has a potential for treatment of obstacles in other hollow organs. The system operates at 30 kHz/60W. Safety aspects of ultrasound catheters will be discussed, showing results of the measurement of shunt impedance at different frequencies, which sets the limit for the electrical safety design.     

Central venous pressure measurements: peripherally inserted catheters versus centrally inserted catheters

OBJECTIVE: To determine whether central venous pressure measurements taken from a peripherally inserted central catheter (PICC) correlate with those from a centrally inserted central catheter (CICC). DESIGN: A pilot bench study followed by a prospective, non-blinded, clinical comparison. SETTING: A 16-bed medical coronary intensive care unit and a 30-bed surgical intensive care unit at a university hospital. PATIENTS: Seven surgical intensive care unit patients and five medical coronary intensive care unit patients. INTERVENTIONS: During the bench study, a simple manometer system was set up to test the catheters. During the clinical study, measurements of central venous pressure were recorded from patients who had an indwelling CICC and PICC concomitantly. Positions of the catheter tips in the chest were verified by radiography. Paired central venous pressure measurements were taken from 19-gauge dual-lumen PICCs and from 7-Fr, 16-gauge, 18-gauge, and pulmonary artery catheter CICCs, all with continuous pressure infusion devices. MEASUREMENTS AND MAIN RESULTS: Bench work showed that PICCs, because of their longer length and narrower lumen, have a higher inherent resistance, which can be overcome with a continuous infusion device. During the clinical study, three to 12 paired, digital, central venous pressure measurements were recorded from each of 12 patients for a total of 77 data pairs. Measurements were recorded at end-expiration. Mean central venous pressure from the CICCs was 11 + 7 mm Hg, and from the PICCs was 12 + 7 mm Hg. PICC pressure versus CICC pressure correlated (r = 0.99) for all data pairs. Analysis by repeated measures showed PICC central venous pressure more than CICC central venous pressure by 1.0 + 3.2 mm Hg (p = 0.02). CONCLUSIONS: PICCs can be used to measure central venous pressure and to follow trends in a clinical setting when used with a pressure infusion device to overcome the natural resistance of the PICC. Central venous pressure recorded via PICCs is slightly higher, but the difference is clinically insignificant.     

Peripherally inserted central venous catheters and central venous catheters related thrombosis in post-critical patients

Background  

Peripherally inserted central venous catheters (PICC) have been proposed as an alternative to central venous catheters (CVC). The aim of this study was to determine the thrombosis rate in relation to PICC placement in patients discharged from the intensive care unit (ICU).