A Five-Year Data Report of Long-Term Central Venous Catheters Focusing on Early Complications.

BACKGROUND: Long-term venous access has become the standard practice for the administration of chemotherapy, fluid therapy, antibiotics, and parenteral nutrition. The most commonly used methods are percutaneous puncture of the subclavian and internal jugular veins using the Seldinger technique or surgical cutdown of the cephalic vein. METHODS: This study is based on a quality registry including all long-term central venous catheter insertion procedures performed in patients >18 years at our department during a five-year period. The following data were registered: demographic data, main diagnosis and indications for the procedure, preoperative blood samples, type of catheter, the venous access used, and the procedure time. In addition, procedural and early postoperative complications were registered: unsuccessful procedures, malpositioned catheters, pneumothorax, hematoma complications, infections, nerve injuries, and wound ruptures. The Seldinger technique using anatomical landmarks at the left subclavian vein was the preferred access. Fluoroscopy was not used. RESULTS: One thousand one hundred and one procedures were performed. In eight (0.7%) cases, the insertion of a catheter was not possible, 23 (2.1%) catheters were incorrectly positioned, twelve (1.1%) patients developed pneumothorax, nine (0.8%) developed hematoma, and three (0.27%) developed infection postoperatively. One (0.1%) patient suffered nerve injury, which totally recovered. No wound ruptures were observed. CONCLUSIONS: We have a high success rate of first-attempt insertions compared with other published data, as well as an acceptable and low rate of pneumothorax, hematoma, and infections. However, the number of malpositioned catheters was relatively high. This could probably have been avoided with routine use of fluoroscopy during the procedure.

Transthoracic impedance changes as a tool to detect malpositioned tracheal tubes.

BACKGROUND: Undetected malpositioned or dislodged ventilation tubes during cardiac arrest have fatal consequences, and no single method can detect the tube position reliably during such low-flow states. We wanted to test the ability of impedance changes as measured across the chest via the standard defibrillation pads to distinguish between oesophageal and tracheal ventilations in non-circulated patients. MATERIALS AND METHODS: After the end of futile resuscitation transthoracic impedance was measured with a prototype defibrillator, and ventilation variables were collected with a spirometer-capnography unit during tracheal ventilations and after repositioning of the tube; during oesophageal ventilations for paired comparisons. RESULTS: We registered 123 oesophageal and 178 tracheal ventilations in nine patients. Transthoracic impedance changes associated with ventilations were always larger during tracheal than oesophageal ventilations (mean difference 1.3 ohms (95% CI 1.0, 1.5), P<0.001), and all such changes above 1.2 ohms were associated with tracheal ventilations, while changes below 0.4 ohms always were associated with oesophageal ventilations. By subtracting 0.5 ohms from the individual mean transthoracic change associated with tracheal ventilations, tube position was predicted with sensitivity 0.99 and specificity 0.97. CONCLUSION: Transthoracic impedance changes may be used to detect malpositioned and dislodged tubes also during situations without spontaneous circulation. Our predictive values must be retested in another population.

Arterial blood gases during basic life support of human cardiac arrest victims.

BACKGROUND: Ventilation with tidal volumes sufficient to raise the victim's chest is an integral part of guidelines for lay-rescuer basic life support, but optimal tidal volume, frequency and ratio to chest compressions are not known. METHODS: Adults with non-traumatic, out-of-hospital cardiac arrest, who were not successfully resuscitated following advanced life support by the staff of a physician-manned ambulance, were included. Advanced life support comprised tracheal intubation and mechanical ventilation with tidal volume of 700 ml and 100% oxygen, 12 times per min. An arterial blood sample was drawn at the end of the resuscitation attempt and analysed on the scene. After the victim was declared dead, basic life support was initiated with chest compressions and mouth-to-mask or mouth-to-tracheal tube ventilation (15:2), with volumes sufficient to make the chest rise. The tracheal tube was equipped with an impedance valve to avoid passive ventilation secondary to chest compressions. Arterial blood samples were drawn after 7-8 min of basic life support and analysed on the scene. RESULTS: Six men and two women, median (range) age 72 (32-86) years, were included in the study. Four of these received mouth-to-mask ventilation and four mouth-to-tracheal tube ventilation. Mean (S.D.) arterial blood carbon dioxide and oxygen tension during advanced life support were 6.4 (1.4)kPa and 22 (15)kPa, respectively. Similar values during basic life support were 9.6 (1.9)kPa and 8.5 (1.6)kPa, respectively, with no differences between the ventilation methods. CONCLUSION: Ventilation during basic life support performed according to international guidelines (2000) resulted in arterial hypercapnia and hypoxia.

Dispatcher-assisted cardiopulmonary resuscitation. An evaluation of efficacy amongst elderly.

Bystander cardiopulmonary resuscitation (CPR) increases survival rates. The largest group of cardiac arrest patients are men over the age of 60 in the home, and the most probable potential CPR provider is an older woman who is not likely to have received CPR training. One method to increase the percentage of bystander-initiated CPR in this setting is for CPR instruction to be provided by nurse dispatchers via telephone. Two male and 18 female volunteers with a median age of 78 years and no previous CPR experience performed 9 min of telephone assisted CPR on a manikin. They were randomised to receive telephone instructions in chest compressions alone or standard CPR including mouth-to-mouth ventilation. Variables were registered by a recording manikin, visual observations, and video and audiotape recordings. The median period from dispatcher contact until continuous CPR was significantly longer for standard instructions than for compression only, 4.9 versus 3.4 min, and fewer chest compressions were provided during the 9 min test period, median 124 versus 334 compressions. In both groups the overall CPR performance was of very poor quality, and unlikely to have affected outcome in a real situation. Other telephone assisted CPR scripts should be tested in this potential bystander group.

Evaluation of a defibrillator-basic cardiopulmonary resuscitation programme for non medical personnel.

To improve the outcome for out-of-hospital patients with ventricular fibrillation/pulseless ventricular tachycardia (VF/VT), the use of automated external defibrillators (AEDs) by first responders including non-medical personnel with a duty to respond to an emergency is recommended. A special CPR-AED course has been developed. We wanted to test the results (quality and speed of operating an AED and CPR) after completion of such a course and retention after approximately 1-year. At the same time we wanted to see if personnel could use an AED after receiving written information without having attended the course. Study subjects were divided randomly into groups, and tested pre-course (n=54), post-course (n=50), and unannounced 10+/-3 months after the course (retention group, n=61). For statistical analysis two sample tests for binomial proportions and Wilcoxon-Mann-Whitney test was used as appropriate. Fifteen of the 27 pairs (56%) in the pre-course group with no previous exposure to an AED decided to use it. There was no difference between the groups in electrode pad positioning, and all stayed clear of the manikin during the process of AED charging and shock delivery. The post-course group had a higher rate of checking for responsiveness (vs. pre-course), not to check for a pulse (vs. both other groups), the shortest time interval from arrival on scene to start of CPR and shock delivery, and in parallel the shortest hands-off interval (without chest compressions and ventilations) before shock delivery. The quality of chest compressions was improved by the course but decreased to a similar standard as in the pre-course when tested 10+/-3 months later, except for correct depth which was similar to post course. Most ventilation attempts in all groups were scored as incorrect due to the high incidence of excessively rapid inflations. The retention group had a lower frequency of correct inflations than the pre-course group, and the post-course group the highest number of correct ventilations per minute. These findings suggest that use of an AED by untrained laypersons may be feasible and that complex and time-consuming training programmes may not be necessary. The present study also supports the need for annual training and recertification.

Mechanical chest compressions with trapezoidal waveform improve haemodynamics during cardiac arrest.

BACKGROUND: During manual chest compressions for cardiac arrest the waveforms of chest compressions are generally sinusoidal, whereas mechanical chest compression devices can have different waveforms, including trapezoidal. We studied the haemodynamic differences of such waveforms in a porcine model of cardiac arrest. METHODS: Eight domestic pigs (weight 31±3kg) were anaesthetised and instrumented to continuously monitor aortic (AP) and right atrial pressure (RAP), carotid (CF) and cerebral cortical microcirculation blood flow (CCF). Coronary perfusion pressure (CPP) was calculated as the maximal difference between AP and RAP during diastole or decompression phase. After 4 min of electrically induced ventricular fibrillation, mechanical chest compressions were performed with four different waveforms in a factorial design, and in randomized sequence for 3 min each. Resulting differences are presented as mean with 95% confidence intervals. RESULTS: Mean AP and RAP were higher with trapezoid than sinusoid chest compressions, difference 5.7 (0.7, 11) and 6.3 (2.1, 11)mmHg, respectively. Flow measured as CF and CCF was also improved with trapezoidal waveform, difference 14 (2.8, 26)ml/min and 11 (5.6, 17)% of baseline, respectively, with a parallel, non-significant (P=0.08) trend for CPP. Active vs. passive decompression to zero level improved CF, but without even a trend for CPP. CONCLUSION: Trapezoid chest compressions and active decompression to zero level improved blood flow to the brain. The compression waveform is an additional factor to consider when comparing mechanical and manual chest compressions and when comparing different compression devices.

Manikins with human-like chest properties--a new tool for chest compression research.

Commercially available training manikins for cardiopulmonary resuscitation (CPR) do not accurately mimic the mechanical properties of human chests. This may limit the usefulness of CPR research performed on such manikins. This paper presents the construction of manikins with chest properties matching those measured in patients during an ongoing CPR. The chest stiffness and damping of 59 cardiac arrest patients was measured during out-of-hospital CPR, using a defibrillator with a compression sensor with built-in force sensor and accelerometer. A manikin with eight interchangeable chest force-depth profiles, representing the measured range of chest stiffness and the average damping of these patients, was then specified and constructed. The stiffness and damping of the manikins were verified using the same equipment and method as was used during data collection. Between 30 and 50 mm compression depth, the force-depth relationship of all eight manikins were found to be within +/-30 N of force or +/-2 mm of depth from the reference specifications derived from measurements on patients' chests. The average damping was also found to closely match the specified value.