s critical care becomes more advanced, t h e information provided by intraoperative and bedside hernodynamic monitoring is increasingly valuable. Efficiency and accuracy in the monitoring system are the desirable goals, when indwelling catheters are used for administration of fluids, monitoring arterial pressure, blood sampling, assessing left ventricular function, or monitoring response to therapy. Because of the increasing amount of hemodynamic monitoring done in our hospital's medical-surgical intensive care unit (ICU) and in the coronary unit, we needed to devise a safe, efficient, and convenient monitoring setup. A consistent, standardized setup would contribute to a sense of confidence among nursing staff as to their ability to initiate and maintain accurate monitoring. After working with several types of tubing, stopcocks, and design patterns and receiving input from the ICU staff and our biomedical clinical technicians, we devised a setup to meet these needs. We reviewed the use of some prepackaged monitoring kits on the mar-
A Hemodynamic monitoring setup Barbara A Gill, RN
Barbara A Gill, R N , BSN, is a cardiovascular clinician at Bethany Medical Center, Kansas City, Kan. Gill received her BSN from the University of Missouri School of Nursing, Columbia. This article was written while Gill was a cardiovascularnurse specialistat Trinity Lutheran Hospital, Kansas City, Mo.
156
AORN Journal, March 1979, V o l 2 9 , No 4
ket, but believe that our setup specifically meets our needs. All components of the system are assembled in the Central Supply Department of the hospital. They are then packaged, gas sterilized, aerated, and delivered t o the units (Fig 1). The heparinized fluid and the transducer are the only necessary additions. The entire system enables us t o visualize a physiological event by transforming it to an electrical signal. Correct transducer placement is mandatory for correct readings. The transducer uses a fluid-filled column that, when electrically calibrated, produces a signal that can be amplified and measured and is proportional to the pressure change. If the transducer is lower than the heart, the hydrostatic pressure of the fluid column between the heart chamber and the transducer will yield a falsely high pressure. Likewise, if the transducer is higher than the heart, the pressure will be falsely low. Thus, the transducer should be positioned level with the midchest with the patient supine. We use a disposable, clear plastic transducer dome to assist in detecting air bubbles. A diaphragm in the dome enables the fluid system t o remain sterile without requiring sterilization of the transducer. The dome has one opening for attachment of the catheter to the transducer and one opening for exposure to atmospheric pressure via the upright stopcock, which provides a reference for calibration. By using a threeway stopcock from the sidearm of the dome, we are able to maintain a concurrent visual pressure curve and an irrigation flow from the fluid source. To calibrate to atmospheric pressure, the sidearm stopcock is rotated so that it is closed to the transducer, but still open from the irrigant to the indwelling line. This aids in maintaining patency and preventing the introduction of air into
758
Fig 1. All components of the monitoring system are prepackaged and sterilized in the hospital's central supply department.
the indwelling catheter during calibration. The transducer is then opened to air via the upright stopcock. Patency may be a problem when an indwelling catheter is used for continuous pressure monitoring. By providing a continuous flow sufficient to keep the catheter patent, but not large enough to alter the pressure, we can preserve the line for an extended length of time. The combination of a pressurized fluid system and a Sorenson Intraflowm t o deliver 6 cc of heparinizedfluid per hour may prevent stasis and clotting. The Sorenson Intraflowm also allows for closed-system flushing. High-pressure tubing is used from the transducer to the indwelling catheter to minimize the loss of pressure to the transducer (Figs2 and 3). The performance of any equipment used in the operating room or in the intensive care unit can only be evaluated in terms of its contribution to the care of the patient. The following case study illustrates the efficiency and accuracy of our monitoring setup. Mrs A, a 60-year-old female patient, entered the hospital for evaluation of
AORN Journal, March 1979,Vol29, No 4
Fig 2. (top). High-pressure tubing is used to minimize loss of pressure to the transducer. Figure 3 (bottom) shows the system assembled for arterial monitoring and left atrial monitoring. 760
a heart murmur. She reported blackout spells and was found to be in atrial fibrillation upon admission. The diagnostic process began to determine whether her symptoms were due to transient ischemic attacks or embolic incidents. A cardiac catheterization revealed severe mitral stenosis and regurgitation, slightly diminished left ventricular function, and normal coronary arteries. Mrs A was subsequently taken to surgery, where a mitral commissurotomy was performed. She arrived in ICU immediately following surgery with an arterial line, a left atrial line, and a central venous pressure line inserted via the left subclavian. Each line was capped by the anesthesiologist at the end of surgery for rapid transport to the ICU, where the monitoring setup had been assembled and calibrated. Upon arrival, each line was described by the anesthesiologist and given to the nurse. After connection and flushing, each transducer was recalibrated, and the initial readings were recorded and correlated with the readings during surgery. The baseline parameters, which would be continuously monitored, were documented within five minutes of Mrs As arrival in ICU. Mrs A then had a stat blood gas sample drawn from the arterial line. This was repeated in 20 minutes and frequently during the next few hours, with every ventilator adjustment during the weaning process leading to extubation. This procedure was facilitated by the three-way stopcock located at the hub of the intracath. The interflow fast-flush device maintained the patency of the line following the sampling and preserved the system not only for the drawing of future samples, but also for continuing arterial pressure monitoring.
AORN Journal, March 1979,Vol29, No 4
d-
By monitoring Mrs A’s arterial pressure, we could measure the direct or true aortic pressure as it reflects upon systemic circulation. The cuff pressure measured via the brachial artery is a damped estimate of the true aortic pressure. It is slightly lower due to the tissue and muscle factor in the extremity. The arterial pulse or pressure obtained through the arterial line is the direct injection of blood from the left ventricle into the aorta and great vessels. Arterial pressure monitoring also more accurately reflects the status of the patient’s circulatory volume. For example, a low, rapid wave formation or a pulsus alternans may indicate hypovolemia. This parameter, in conjunction with other vital signs, aids in the full assessment of the patient’s status. In Mrs A’s case, as may be desirable with other left-sided cardiac operations, monitoring left ventricular filling pressure is helpful with intraoperative and postoperative assessment. This pressure can be estimated with a pulmonary artery balloon catheter, but it is most reliable to measure left artrial pressure directly. Accurate monitoring of this parameter assisted the critical care staff in adjusting Mrs As fluid therapy in accordance with her left ventricular function. The left atrial line was removed 24 hours following surgery, as Mrs A’s condition was satisfactory and stable. The ease and efficiency of the preassembled, prepackaged monitoring setup coupled with safety and consistency factors have enabled critical care nurses to achieve better hemodynamic monitoring. However, in planning and implementing the care of patients involved with bedside hemodynamic monitoring, the monitoring kit that we devised is only a helpful adjunct. Aseptic technique, prevention of air emboli, and meeting the psychological needs of
764
a patient needing critical care cannot be minimized. 0 Suggested reading Gardner, Reed M; Warner, Homer R; Toronto, Alan F; Gaisford, Walter D. “Catheter-flush system for continuous monitoring of central pulse waveform.” Journal of Applied Physiology 29 (1970) 911-912.
Lamb, Joan. “lntra-arterial monitoring.”Nursing ’77 7 (1977) 65-75.
Schroeder, John Speer; Daily, Elaine Kiess. Techniques in Bedside Hemodynamic Monitoring. St Louis: C V Mosby Co, 1976. Swan, J J C. ”What is the role of invasive monitoring procedures in the management of the critically ill?” Cardiovascular Clinic 8 (1977) 103-111.
NLN offers catalog of achievement tests The National League for Nursing (NLN), has announced the publication of its 1978-1979 catalog of achievement and preadmission tests for use by nursing education programs. Test Services for Schools of Nursing describes each of the nationally standardized tests available from the League’s division of measurement and other NLN evaluation services. The catalog details areas included in NLN’s achievement tests, which are designed to measure individual performance. Subject areas include anatomy and physiology, pharmacology, chemistry,nutrition, maternity and child nursing, psychiatry, microbiology, and community health nursing. The achievement tests are developed for all registered nursing programs, as well as for licensed practical and vocational nursing programs. The tests are designed to be administered either at the end of a course, following a major learning experience, or at the close of a program. The 32-page catalog also describes the admissions testing services available from the League, for the guidance and placement of applicants to schools of nursing. Test Services for Schools of Nursing can be obtained at no charge by writing National League for Nursing, Ten Columbus Cir, New York, NY 10019.
AORN Journal, March 1979,V o l 2 9 , No 4
A Hemodynamic monitoring setup Barbara A Gill, RN
Barbara A Gill, R N , BSN, is a cardiovascular clinician at Bethany Medical Center, Kansas City, Kan. Gill received her BSN from the University of Missouri School of Nursing, Columbia. This article was written while Gill was a cardiovascularnurse specialistat Trinity Lutheran Hospital, Kansas City, Mo.
156
AORN Journal, March 1979, V o l 2 9 , No 4
ket, but believe that our setup specifically meets our needs. All components of the system are assembled in the Central Supply Department of the hospital. They are then packaged, gas sterilized, aerated, and delivered t o the units (Fig 1). The heparinized fluid and the transducer are the only necessary additions. The entire system enables us t o visualize a physiological event by transforming it to an electrical signal. Correct transducer placement is mandatory for correct readings. The transducer uses a fluid-filled column that, when electrically calibrated, produces a signal that can be amplified and measured and is proportional to the pressure change. If the transducer is lower than the heart, the hydrostatic pressure of the fluid column between the heart chamber and the transducer will yield a falsely high pressure. Likewise, if the transducer is higher than the heart, the pressure will be falsely low. Thus, the transducer should be positioned level with the midchest with the patient supine. We use a disposable, clear plastic transducer dome to assist in detecting air bubbles. A diaphragm in the dome enables the fluid system t o remain sterile without requiring sterilization of the transducer. The dome has one opening for attachment of the catheter to the transducer and one opening for exposure to atmospheric pressure via the upright stopcock, which provides a reference for calibration. By using a threeway stopcock from the sidearm of the dome, we are able to maintain a concurrent visual pressure curve and an irrigation flow from the fluid source. To calibrate to atmospheric pressure, the sidearm stopcock is rotated so that it is closed to the transducer, but still open from the irrigant to the indwelling line. This aids in maintaining patency and preventing the introduction of air into
758
Fig 1. All components of the monitoring system are prepackaged and sterilized in the hospital's central supply department.
the indwelling catheter during calibration. The transducer is then opened to air via the upright stopcock. Patency may be a problem when an indwelling catheter is used for continuous pressure monitoring. By providing a continuous flow sufficient to keep the catheter patent, but not large enough to alter the pressure, we can preserve the line for an extended length of time. The combination of a pressurized fluid system and a Sorenson Intraflowm t o deliver 6 cc of heparinizedfluid per hour may prevent stasis and clotting. The Sorenson Intraflowm also allows for closed-system flushing. High-pressure tubing is used from the transducer to the indwelling catheter to minimize the loss of pressure to the transducer (Figs2 and 3). The performance of any equipment used in the operating room or in the intensive care unit can only be evaluated in terms of its contribution to the care of the patient. The following case study illustrates the efficiency and accuracy of our monitoring setup. Mrs A, a 60-year-old female patient, entered the hospital for evaluation of
AORN Journal, March 1979,Vol29, No 4
Fig 2. (top). High-pressure tubing is used to minimize loss of pressure to the transducer. Figure 3 (bottom) shows the system assembled for arterial monitoring and left atrial monitoring. 760
a heart murmur. She reported blackout spells and was found to be in atrial fibrillation upon admission. The diagnostic process began to determine whether her symptoms were due to transient ischemic attacks or embolic incidents. A cardiac catheterization revealed severe mitral stenosis and regurgitation, slightly diminished left ventricular function, and normal coronary arteries. Mrs A was subsequently taken to surgery, where a mitral commissurotomy was performed. She arrived in ICU immediately following surgery with an arterial line, a left atrial line, and a central venous pressure line inserted via the left subclavian. Each line was capped by the anesthesiologist at the end of surgery for rapid transport to the ICU, where the monitoring setup had been assembled and calibrated. Upon arrival, each line was described by the anesthesiologist and given to the nurse. After connection and flushing, each transducer was recalibrated, and the initial readings were recorded and correlated with the readings during surgery. The baseline parameters, which would be continuously monitored, were documented within five minutes of Mrs As arrival in ICU. Mrs A then had a stat blood gas sample drawn from the arterial line. This was repeated in 20 minutes and frequently during the next few hours, with every ventilator adjustment during the weaning process leading to extubation. This procedure was facilitated by the three-way stopcock located at the hub of the intracath. The interflow fast-flush device maintained the patency of the line following the sampling and preserved the system not only for the drawing of future samples, but also for continuing arterial pressure monitoring.
AORN Journal, March 1979,Vol29, No 4
d-
By monitoring Mrs A’s arterial pressure, we could measure the direct or true aortic pressure as it reflects upon systemic circulation. The cuff pressure measured via the brachial artery is a damped estimate of the true aortic pressure. It is slightly lower due to the tissue and muscle factor in the extremity. The arterial pulse or pressure obtained through the arterial line is the direct injection of blood from the left ventricle into the aorta and great vessels. Arterial pressure monitoring also more accurately reflects the status of the patient’s circulatory volume. For example, a low, rapid wave formation or a pulsus alternans may indicate hypovolemia. This parameter, in conjunction with other vital signs, aids in the full assessment of the patient’s status. In Mrs A’s case, as may be desirable with other left-sided cardiac operations, monitoring left ventricular filling pressure is helpful with intraoperative and postoperative assessment. This pressure can be estimated with a pulmonary artery balloon catheter, but it is most reliable to measure left artrial pressure directly. Accurate monitoring of this parameter assisted the critical care staff in adjusting Mrs As fluid therapy in accordance with her left ventricular function. The left atrial line was removed 24 hours following surgery, as Mrs A’s condition was satisfactory and stable. The ease and efficiency of the preassembled, prepackaged monitoring setup coupled with safety and consistency factors have enabled critical care nurses to achieve better hemodynamic monitoring. However, in planning and implementing the care of patients involved with bedside hemodynamic monitoring, the monitoring kit that we devised is only a helpful adjunct. Aseptic technique, prevention of air emboli, and meeting the psychological needs of
764
a patient needing critical care cannot be minimized. 0 Suggested reading Gardner, Reed M; Warner, Homer R; Toronto, Alan F; Gaisford, Walter D. “Catheter-flush system for continuous monitoring of central pulse waveform.” Journal of Applied Physiology 29 (1970) 911-912.
Lamb, Joan. “lntra-arterial monitoring.”Nursing ’77 7 (1977) 65-75.
Schroeder, John Speer; Daily, Elaine Kiess. Techniques in Bedside Hemodynamic Monitoring. St Louis: C V Mosby Co, 1976. Swan, J J C. ”What is the role of invasive monitoring procedures in the management of the critically ill?” Cardiovascular Clinic 8 (1977) 103-111.
NLN offers catalog of achievement tests The National League for Nursing (NLN), has announced the publication of its 1978-1979 catalog of achievement and preadmission tests for use by nursing education programs. Test Services for Schools of Nursing describes each of the nationally standardized tests available from the League’s division of measurement and other NLN evaluation services. The catalog details areas included in NLN’s achievement tests, which are designed to measure individual performance. Subject areas include anatomy and physiology, pharmacology, chemistry,nutrition, maternity and child nursing, psychiatry, microbiology, and community health nursing. The achievement tests are developed for all registered nursing programs, as well as for licensed practical and vocational nursing programs. The tests are designed to be administered either at the end of a course, following a major learning experience, or at the close of a program. The 32-page catalog also describes the admissions testing services available from the League, for the guidance and placement of applicants to schools of nursing. Test Services for Schools of Nursing can be obtained at no charge by writing National League for Nursing, Ten Columbus Cir, New York, NY 10019.
AORN Journal, March 1979,V o l 2 9 , No 4
