Ryszard Gawda

Associations between intracranial pressure, intraocular pressure and mean arterial pressure in patients with traumatic and non-traumatic brain injuries.

INTRODUCTION Anatomical proximity of the eye and the intracranial space is a fact but the existence of physiological and pathophysiological relationships between them is elusive. The objective of this study was to explore anatomical and pathophysiological interactions between the eye and the intracranial space and to assess clinical utility of intraocular pressure measurement in estimation of intracranial pressure in patients with brain injuries and to discover how haemodynamic instability could influence these interactions. Controversy surrounds the recent literature concerning this problem and the consensus has not been achieved. MATERIALS AND METHODS We evaluated the correlation between intracranial pressure and intraocular pressure, intracranial pressure and mean arterial pressure, intraocular pressure and mean arterial pressure in 40 patients with brain injuries initially comatose, admitted to our hospital. All patients required the intracranial pressure monitoring on clinical grounds. Simultaneous recordings of intracranial pressure, intraocular pressure and mean arterial pressure were performed. RESULTS We calculated both the linear correlation coefficient and the Spearman rank-order correlation coefficient for all three relations. We found significant correlation between intraocular pressure and mean arterial pressure in 63% of the tested population. When the power of the test was increased, by considering only patients with 11 or more observations, this ratio increased to 76%. However, the correlation between intraocular pressure and intracranial pressure, as well as, between intracranial pressure and mean arterial pressure was not significant. CONCLUSIONS There is no anatomical and pathophysiological basis for the statement that intraocular pressure can be used as an indirect estimator of intracranial pressure.

Supraclavicular approach is an easy and safe method of subclavian vein catheterization even in mechanically ventilated patients: analysis of 370 attempts.

Background:Central venous catheters are commonly inserted for hemodynamic monitoring, volume monitoring, administration of medications, long-term total parenteral nutrition, access for renal replacement therapy, cardiopulmonary resuscitation, and difficult peripheral catheterization. The primary outcome of this study was to define venipuncture, catheterization and entire procedure success rates, and finally complication rate of subclavian venous catheterization via the supraclavicular approach with special focus on mechanically ventilated patients. The secondary outcome was to potentially make recommendations regarding this technique of central venous catheterization in mechanically ventilated patients. Methods:The methodology of this prospective cohort study included subclavian venous catheterization via the supraclavicular approach. The technique of cannulation was the same for both the right and left sides, but the right claviculosternocleidomastoid angle was the preferred catheterization site. All procedures were performed by the first three authors, each of whom had different levels of experience. Each physician had performed at least 20 procedures before starting the study. Results:In the majority of patients, venipuncture occurred during the first attempt. In 362 patients, catheterization attempts were performed, in whom 311 catheterizations (85.6%) were successful during the first attempt. The overall subclavian venous catheterization via supraclavicular approach procedure complication rate reached 1.7% (95% confidence interval 0.6–3.6%). The overall subclavian venous catheterization via the supraclavicular approach procedure success rate reached 88.9% (95% confidence interval 85.1–91.9%, n = 359). Conclusions:Subclavian venous catheterization via the supraclavicular approach is an excellent method of central venous access in mechanically ventilated patients. The procedure success rate and the significant complication rate are comparable to other techniques of central venous catheterization.

Real-time ultrasound-guided infraclavicular axillary vein cannulation: A prospective study in mechanically ventilated critically ill patients

PURPOSE The main purpose of this study was to define the venipuncture and catheterization success rates and early mechanical complication rates of ultrasound-guided infraclavicular axillary vein cannulation. MATERIALS AND METHODS We performed in-plane, real-time, ultrasound-guided infraclavicular axillary vein catheterizations under emergency and nonemergency conditions in mechanically ventilated, critically ill patients. RESULTS We performed 202 cannulation attempts. One hundred and twenty-six procedures (62.4%) were performed under emergency conditions. The puncture of the axillary vein was successful in 98.5% of patients, and the entire procedure success rate was 95.1% (95% confidence interval, 91.1%-97.6%). For the majority of patients (84.1%; P<.001, exact test), the venipuncture occurred during the first attempt. We noted a 22.4% overall complication rate, and most of the complications were malpositions (13.4%). We observed 8.5% of cases with potentially serious complications (puncture of the axillary artery and needle contact with the brachial plexus) and 1 case (0.5%) of pneumothorax. The puncture of the axillary artery occurred in 5 (2.5%) patients. CONCLUSIONS In-plane, real-time, ultrasound-guided, infraclavicular axillary vein cannulation in mechanically ventilated, critically ill patients is a safe and reliable method of central venous cannulation and can be considered to be a reasonable alternative to other central venous catheterization techniques.

Real-time, ultrasound-guided infraclavicular axillary vein cannulation for renal replacement therapy in the critical care unit—A prospective intervention study

PURPOSE The cannulation of the axillary vein for renal replacement therapy is a rarely performed procedure in the critical care unit. We defined the venipuncture and catheterization success rates and early mechanical complication rates of this technique in critical care patients with acute kidney injury. MATERIALS AND METHODS Twenty-nine mechanically ventilated patients with clinical indications for insertion of temporary hemodialysis catheters enrolled in a registered trial (NCT01919528) as a pilot cohort. We performed 29 real-time, ultrasound-guided infraclavicular axillary vein cannulation attempts for renal replacement therapy. We defined the venipuncture and catheterization success rates and early mechanical complication rates for this technique. RESULTS The puncture of the axillary vein was successful in 28 (96.5%) patients. In 22 patients (75.9%), venipuncture occurred during the first attempt and in 6 patients during the second (20.7%). The overall cannulation success rate was 93.1% (95% confidence interval, 77%-99%). We noted 6.8% potentially serious complications rate, 10.3% minor complications rate, and 0% life-threatening early mechanical complications. We achieved an 89.6% renal replacement therapy success rate and low rate of catheters malfunction. CONCLUSIONS Real-time, ultrasound-guided, infraclavicular axillary vein cannulation for renal replacement therapy in the critical care unit is a reliable method of dual-lumen hemodialysis catheter insertion and can be considered a reasonable alternative to jugular and femoral routes in special clinical circumstances.

Vitamin D kinetics in the acute phase of critical illness: A prospective observational study

Purpose: The objective of this study was to assess the vitamin D kinetics in critically ill patients by performing periodic serum vitamin D measurements in short time intervals in the initial phase of a critical illness. Materials and methods: We performed vitamin D serum measurements: at admission and then in 12‐hour time intervals. The minimum number of vitamin D measurements was 4, and the maximum was 8 per patient. Results: A total of 363 patients were evaluated for participation, and 20 met the inclusion criteria. All patients had an initial serum vitamin D level between 10.6 and 39 ng/mL. Nineteen patients had vitamin D levels between 10 and 30 ng/mL, which means that they had vitamin D insufficiency or deficiency, and only one patient had a normal vitamin D serum plasma level. We observed that the median of the vitamin D level decreases until the fourth measurement then stabilizes around the 4th and 5th measurement and then appears to increase unevenly. The highest drop is at the very beginning. Conclusions: The vitamin D serum level is changeable in the initial phase of a critical illness. We hypothesize that the serum vitamin D concentration can mirror the severity of illness. Highlights:The vitamin D kinetics in critically ill patients was studied.The vitamin D serum level is changeable in the initial phase of a critical illness.The median of the vitamin D level decreases until the fourth measurement then stabilizes and finally increases unevenly.One of the most likely reasons for such an observation could be a hypothesis that the serum vitamin D concentration mirrors the severity of illness.

A systematic approach to ultrasound-guided central venous catheter placement—desirable modifications

With much interest we read the paper written by Saugel et al. [1] on a systemic approach to ultrasound-guided central vein catheterization. The article is comprehensive but some issues need discussing. The authors claim that the tip of the needle can be constantly identified while the needle is approaching the vein both in short-axis and long-axis views. This is inaccurate. The only approach where it is possible to constantly visualize the tip of the needle is the inplane technique. In the short-axis view, the needle is visible as a white dot, which also applies to the tip of the needle as with any part of the needle shaft [2, 3]. It means that the tip can be within the lumen of the vein or below the vessel when the second wall of the vein is punctured. The scheme created by the authors is similar to the one we recently published [4]. Unfortunately, their proposed systematic approach ignores several crucial steps in the procedure. Firstly, the needle is not always visualized perfectly. Therefore, before puncturing the vein, you need to check if the needle has not been positioned over the adjacent artery. How this is done depends on the technique used. It is simple in the short-axis view, when both vessels are constantly presented on the screen, but in the long-axis view, only the vein is visualized; thus, the angle needs to be changed between the ultrasound probe and the skin in order to visualize the adjacent artery. When the tip of the needle is not centrally positioned over the vein, the needle can miss the vein, also damaging the adjacent artery. The other important step is to test the introduction of the guidewire, i.e., to check whether the tip of the guidewire is not being introduced into the other central vein on the same side of the patient. This problem mostly concerns the jugular vein during axillary/subclavian vein catheterization and the axillary/subclavian vein during jugular vein catheterization. This step acts as a protection (but not completely) against introducing the catheter into an undesirable location. In our opinion ultrasound-guided central venous catheter placement is a slightly more complex procedure than the one proposed in the paper. It not only involves introducing the catheter into the vein but also controls all the steps in order to guarantee the safety of the patient.

Infraclavicular access to the axillary vein — new possibilities for the catheterization of the central veins in the intensive care unit

Central vein cannulation is one of the most commonly performed procedures in intensive care. Traditionally, the jugular and subclavian vein are recommended as the first choice option. Nevertheless, these attempts are not always obtainable for critically ill patients. For this reason, the axillary vein seems to be a rational alternative approach. In this narrative review, we evaluate the usefulness of the infraclavicular access to the axillary vein. The existing evidence suggests that infraclavicular approach to the axillary vein is a reliable method of central vein catheterization, especially when performed with ultrasound guidance.

A new infraclavicular landmark-based approach to the axillary vein as an alternative method of central venous cannulation

Purpose We developed the new technique of the axillary vein catheterization, which is connected with the determination of only two anatomical points of reference for puncture site identification. The primary outcome of this study was to determine the rate of successful catheterizations and the assessment of procedure success rate, depending on cannulation side as well as physician experience. The secondary objective was to evaluate the early complication rate and to determine whether this method can be used in clinical practice. Methods The methodology of this prospective, cohort study included catheterization of the axillary vein via the infraclavicular approach. All procedures were performed by the first two authors, each of whom had different levels of experience with the technique. The choice of the cannulation side was based on clinical factors, and the technique was identical on the right and left sides. Results The cannulation success rate reached 85.6% (N = 153). The correlation between physician experience and the procedure success rate as well as between cannulation side and procedure success rate were not significant. A common early complication was a puncture of axillary artery (14.4%) with the following proper cannulation in the majority of patients (77.3%, p<0.01, exact test). Conclusions The procedure success rate, 85.6% (95% CI [80.0, 91.2%]), is comparable to other landmark-based techniques of the central vein cannulation. The moderately high percentage of axillary artery puncture points out that the approach should be used only as an alternative method to the central vein catheterization.