ANALISA ARTIKEL ILMIAH KESALAHAN DALAM PENGUKURAN TEKANAN VENA CENTRAL Disusun untuk memenuhi tugas mata kuliah Keperawatan Kritis II Dosen Pembimbing : Ns. Baskoro, S. Kep. Disusun Oleh : Kelompok A3 Anggota : 1. Heny Ernawati (062310101007) 2. Surahmah (072310101004) 3. Ria Pratiwi Retna H (072310101012) 4. Rahayu Dyah L. (072310101020) 5. Nur Inayati (072310101028) 6. Febri Yunanda Putra (072310101040) 7. Dewi Ayu Rahayu (072310101053) 8. Chandra Aji Permana (072310101062)
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ANALISA ARTIKEL ILMIAH
KESALAHAN DALAM PENGUKURAN TEKANAN VENA
CENTRAL
Disusun untuk memenuhi tugas mata kuliah Keperawatan Kritis II
Dosen Pembimbing : Ns. Baskoro, S. Kep.
Disusun Oleh :
Kelompok A3
Anggota :
1. Heny Ernawati (062310101007)
2. Surahmah (072310101004)
3. Ria Pratiwi Retna H (072310101012)
4. Rahayu Dyah L. (072310101020)
5. Nur Inayati (072310101028)
6. Febri Yunanda Putra (072310101040)
7. Dewi Ayu Rahayu (072310101053)
8. Chandra Aji Permana (072310101062)
PROGRAM STUDI ILMU KEPERAWATAN
UNIVERSITAS JEMBER
2010
BAB 1. PENDAHULUAN
1.1 Latar Belakang
Kesederhanaan yang tampak jelas pada sistem
kardiovaskular ternyata sangat kontradiktif dengan struktur dan
fungsi sirkulasi yang rumit dan berdiri sendiri. Setiap bagian
system kardiovaskular diadaptasi secara unik untuk berperan
dalam respons kardiovaskular yang sangat terintegrasi terhadap
proses penyakit. Oleh karena itu diperlukan pemahaman anatomi
kardiovaskular dan kemampuan serta pembatasan respons
kompensatorik sirkulasi (Price, 2006).
Jantung merupakan organ vital di dalam tubuh kita dan
merupakan hal yang penting untuk deteksi sedini mungkin
terhadap gejala patologis. Sebelum tahun 1800, salah satu cara
untuk menegakkan diagnosa adalah dengan cara menempelkan
telinga pada dada yang akan diperiksa. Kemudian pada awal
1800 dikembangkan stetoskop yang menggunakan mekanisme
tubular untuk mendengarkan langsung suara dari dada ke
pemeriksa untuk evaluasi (Anonim, 2010).
Semakin tahun semakin banyak tersedia teknik diagnostik
canggih untuk mendeteksi penyakit jantung dan sekuele
klinisnya. Namun penggunaan teknik-teknik ini dan interpretasi
hasil pemeriksaan hanyalah sebagai pelengkap penilaian klinis
dan sistematis pasien bersangkutan, dan bukan merupakan
pemeriksaan yang menggantikan anamnesis dan pemeriksaan
fisik lengkap pasien tersebut. Oleh karena itu, harus dilakukan
tinjauan singkat dari pemeriksaan sistematis penderita penyakit
jantung di bangsal sebelum melangkah ke prosedur diagnostik
yang umum (Price, 2006).
Salah satu dari prosedur diagnostik tersebut adalah
pemantauan hemodinamik. Pemantauan hemodinamik dilakukan
terhadap beberapa tekanan intravaskuler dan intrakardia yang
dilakukan sebagai evaluasi status kardiovaskuler secara terus
menerus. Sehingga kondisi pasien dapat terpantau dengan baik.
Oleh karena itu, penulis menyusun makalah tentang pemantauan
hemodinamik ini.
1.2 Tujuan
Penulisan makalah ini memiliki dua tujuan, yaitu tujuan
umum dan tujuan khusus. Tujuan umum lebih memfokuskan
tujuan dari penulisan makalah, antara lain:
1. Mengetahui definisi dari pemantauan tekanan vena sentral
2. Mengetahui fungsi dari pemantauan tekanan vena sentral
3. Mengetahui tata cara atau prosedur untuk melakukan
pemantauan tekanan vena sentral
4. Mengetahui dampak dari penggunaan pemantauan
tekanan vena sentral
Tujuan khusus lebih memfokuskan pada tujuan pembuatan
makalah ini yaitu untuk memenuhi tugas mata kuliah
Keperawatan Kritis II semester gasal.
1.3 Manfaat
Penulis tentunya berharap makalah ini dapat bermanfaat
bagi pambacanya. Sesuai dengan tujuan awal, maka kami harap
para pembaca dapat mengetahui seluk beluk tentang
pemeriksaan tekanan vena sentral mulai dari definisi, fungsi,
prosedur dan dampaknya. Diharapkan dengan pengetahuan
yang sedikit ini nantinya bisa meningkatkan tingkat kesehatan
masyarakat di Indonesia.
BAB 2. TINJAUAN TEORI
2.1 Definisi Monitoring Tekanan Vena Sentral
Tekanan vena sentral merupakan tekanan pada vena besar
thorak yang menggambarkan aliran darah ke jantung (Oblouk,
Gloria Darovic, 2002).
Tekanan vena sentral merefleksikan tekanan darah di
atrium kanan atau vena kava (Carolyn, M. Hudak, et.al, 1998).
Pada umumnya jika venous return turun, CVP turun, dan jika
venous return naik, CVP meningkat.
2.2 Indikasi Pemantauan Tekanan Vena Sentral
1. Mengetahui fungsi jantung
Pengukuran CVP secara langsung mengukur tekanan atrium
kanan (RA) dan tekanan end diastolic ventrikel kanan. Pada
pasien dengan susunan jantung dan paru normal, CVP juga
berhubungan dengan tekanan end diastolic ventrikel kiri.
2. Mengetahui fungsi ventrikel kanan
CVP biasanya berhubungan dengan tekanan (pengisisan)
diastolik akhir ventrikel kanan. Setelah ventrikel kanan terisi,
maka katup tricuspid terbuka yang memungkinkan
komunikasi terbuka antara serambi dengan bilik jantung.
Apabila tekanan akhir diastolik sama dengan yang terjadi
pada gambaran tekanan ventrikel kanan, CVP dapat
menggambarkan hubungan antara volume intravascular,
tonus vena, dan fungsi ventrikel kiri.
3. Menentukan fungsi ventrikel kiri
Pada orang-orang yang tidak menderita gangguan jantung,
CVP berhubungan dengan tekanan diastolik akhir ventrikel kiri
dan merupakan sarana untuk mengevaluasi fungsi ventrikel
kiri.
4. Menentukan dan mengukur status volume intravascular.
Pengukuran CVP dapat digunakan untuk memeriksa dan
mengatur status volume intravaskuler karena tekanan pada
vena besar thorak ini berhubungan dengan volume venous
return.
5. Memberikan cairan, obat obatan, nutrisi parenteral
Pemberian cairan hipertonik seperti KCL lebih dari 40 mEq/L
melalui vena perifer dapat menyebabkan iritasi vena, nyeri,
dan phlebitis. Hal ini disebabkan kecepatan aliran vena perifer
relatif lambat dan sebagai akibatnya penundaan
pengenceran cairan IV. Akan tetapi, aliran darah pada vena
besar cepat dan mengencerkan segera cairan IV masuk ke
sirkulasi. Kateter CVP dapat digunakan untuk memberikan
obat vasoaktif maupun cairan elektrolit berkonsentrasi tinggi.
6. Kateter CVP dapat digunakan sebagai rute emergensi insersi
BACKGROUND: The variability introduced by inconsistent
placement of pressure transducers for invasive monitoring may
result in significant measurement error. Our goals in this study
were to quantify the degree of variation among health care
providers and to identify a simple tool for reducing this error.
METHODS: A sample of 50 perioperative health care providers
was recruited and asked to place a transducer at the appropriate
level for central venous pressure (CVP) monitoring on two
separate occasions: first without any additional standardization
tools and second with a laser level to guide transducer
placement. The variability among providers was calculated, and
the results between sessions compared.
RESULTS: There was significant variation in transducer
placement during both sessions, in some instances, of greater
magnitude than a normal CVP value. The laser level did not
significantly reduce this variation.
CONCLUSION: There is significant variation in transducer
placement among health care providers. This variation is not
reduced by a laser level and must be considered when
interpreting CVP data. Hospital- or institution-wide
standardization of a zero-level should be considered.
Previous Section Next Section
IMPLICATIONS: There is significant variation in transducer
placement among health care providers, which is not reduced or
eliminated by using a laser level and should be considered when
interpreting CVP data.
Previous Section Next Section
The accurate and consistent placement of pressure transducers
for invasive monitoring is critically important. Inaccurate or
inconsistent placement among health care providers may result
in substantial inter-provider variability and significant
measurement error. The variability associated with inaccurate or
inconsistent placement will have greater impact when monitoring
pressures with a lower normal value (i.e., central venous
pressure [CVP]), compared with pressures with a higher normal
value (i.e., systemic arterial blood pressure). The degree and
magnitude of this error is important when interpreting data
obtained by different health care providers. Indeed, recent
studies have emphasized the importance of defining an exact
anatomic zero level for CVP transducers.1
Despite the well-described shortcomings of CVP as a sole monitor
of ventricular preload,2,3 it continues to be an important and
commonly used management tool. As with any such tool, it is
vital to understand potential sources of error and the impact of
this error on clinical decision-making and patient care. The goal
of this study was to evaluate variation in transducer placement
among health care personnel when monitoring CVP and to
identify methods of reducing it.
The goal of the first portion of the study was to quantify the
degree of variation among health care providers, with the
hypothesis that there is significant variation in the placement of
transducers among personnel. The goal of the second portion of
the study was to minimize some of the error by using a
standardization tool. We hypothesize that the use of a laser level
to aid participants in placing these transducers might better
identify the anatomic landmarks and would reduce random error
resulting in less variation in transducer placement among health
care providers.
Previous Section Next Section
METHODS
A sample of 50 perioperative health care providers (14 registered
nurses, 24 residents in anesthesiology, and 12 board-certified
anesthesiologists) familiar with CVP monitoring, were recruited
on two different occasions. On the first occasion (Session 1), the
participants were asked to place a CVP transducer at the
appropriate level on the same mock patient in three positions:
flat supine, approximately 30 degrees head up and
approximately 15 degrees Trendelenburg. The transducer was
placed on an IV pole approximately 1 m from the mock patient.
The height of the transducer (distance from the zero point to the
floor) was recorded for each placement. During the testing
procedure, the subjects did not observe each other position the
transducer.
On the second occasion (Session 2), 6 mo later, the subjects
were again asked to place the CVP transducer at the appropriate
level for the same three patient positions: flat supine,
approximately 30 degrees head up and approximately 15
degrees Trendelenburg on the same mock patient. During this
portion of the study, participants were asked to use a laser level
to help identify anatomic landmarks and place the transducer at
the proper level. Again, the level of the transducer was recorded
for each placement.
Statistical analysis
To quantify the range of CVP transducer levels and the degree of
inter-provider variability present, the mean, standard deviation,
and interquartile range were calculated. To test the efficacy of
the laser level to reduce variation in measurement, Levene’s test
for equality of variances was performed to determine if the
variances between Session 1 and Session 2 were significantly
different. A P < 0.05 was considered statistically significant.
Previous Section Next Section
RESULTS
The standard deviation, interquartile range, and range for
Session 1 (without the laser) and Session 2 (with the laser) are
reported in Table 1 and Table 2. The results of the analysis of the
differences in variances between Session 1 and Session 2 are
reported in Table 3.
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Table 1. Session 1 (Without Laser Level)
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Table 2. Session 2 (With Laser Level)
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Table 3. Comparison of Inter-Provider Variation
There was significant variation among health care providers in
the level of transducer placement during Session 1. Using the
formula 1 cm H20 = 0.736 mm Hg, the standard deviation of
transducer placement among health care providers for each of
the 3 positions was 3.2, 4.8, and 3.2 mm Hg (flat supine,
approximately 30 degrees head up and approximately 15
degrees Trendelenburg, respectively, Table 1). During Session 2,
the standard deviations for each of the three positions were 2.9,
4.3, and 2.6 mm Hg (flat supine, approximately 30 degrees head
up and approximately 15 degrees Trendelenburg, respectively,
Table 2). The use of a laser level did not result in significantly
different variances between Session 1 and Session 2, and did not
reduce the variation in measurement among health care
providers (Table 3).
Previous Section Next Section
DISCUSSION
CVP measurements, either alone or as a trend, are frequently
used to monitor right ventricular preload and serve as a correlate
measure of left ventricular preload. Small changes in CVP may
translate to large changes in physiologic status and vastly
different patient management strategies. Our data demonstrate
that, even in experienced hands, error in CVP measurement may
be equal to or more than the magnitude of a normal CVP value.
In light of the magnitude of this variation, we attempted to
identify an intervention that could minimize variation of CVP
transducer level: the use of a laser level to aid transducer
placement. If the error observed without a laser level was simply
due to parallax, then the use of the level to better identify
anatomic landmarks should eliminate this error. Unfortunately,
the use of the laser level did not significantly decrease the
observed variation in measurement.
Of note, the degree of variation was largest when the mock
patient was placed in the 30 degree head up position. While this
position is not commonly used during surgery, it is frequently
used in the postanesthesia care unit and the intensive care unit.
Indeed, several studies have indicated that positioning
mechanically ventilated patients at >30 degrees is preferred and
associated with a decreased risk of aspiration and ventilator-
associated pneumonia.4,5 It is important to note that critically ill
patients with the most tenuous fluid status are precisely the
group of patients most likely to undergo CVP pressure monitoring
and the group of patients most susceptible to measurement
error. Thus, these data are particularly relevant in the intensive
care unit. Indeed, the variation observed would have significant
impact on clinical decision, i.e., fluid challenge versus diuresis.
Further, other potential inter-provider differences such as
differences, in interpreting the CVP trace or ability to account for
respiratory variation (spontaneous and mechanical breaths),
would likely compound the error observed.
With any measurement, measurement error may be considered
to be the sum of random error and systematic error. Random
error is caused by unpredictable fluctuations in the measured
data due to the precision limitations of the measurement device
or random fluctuations in the clinician’s interpretation of the
device reading.6 By contrast, systematic error is caused by
consistent biases in the device due to improper calibration,
environmental factors or due to biases in the clinician’s
interpretation of the device’s use or reading.6
Since the use of a laser level should have reduced the magnitude
of random error between measurements, we can conclude that
inter-observer variability results predominantly from systematic
error in transducer placement, and not only from random error.
Indeed, it was the anecdotal observation of the authors that
different anatomic landmarks and the selection of suitable
external landmarks varied significantly among participants.
Transducer placement variation that leads to errors in CVP
measurement approaching the value of the CVP itself is an
exceptionally important observation. The use of different
landmarks for transducer placement can result in drastically
different observations, diagnoses, and management decisions.
The inter-provider variability characterized above could
potentially appear when patient care is transferred from one
provider to another, who places the transducer at a different
level. Given the observed magnitude of the error and its potential
to significantly affect patient care, hospital-wide standardization
of an appropriate zero level and provider education on correct
transducer placement should be considered. Furthermore, when
care of a patient is transferred from one provider to another, part
of the “turnover procedure” should include a description of what
external anatomic landmark the provider was using as a
reference.
Previous Section Next Section
CONCLUSION
These data indicate that there is significant inter-provider
variability and that a commonly used intervention to reduce
those differences (a laser level) is not effective. One must
carefully interpret CVP data obtained by different health care
personnel or reported by different authors, and understand the
importance of considering the clinical context of a CVP value
before making management decisions.
DAFTAR PUSTAKA
Seo JH, Jung CW, Bahk JH. Seo JH, Jung CW, JH Bahk. Uppermost blood levels of the right and left atria in the supine position: implication for measuring central venous pressure and pulmonary artery wedge pressure. Anesthesiology 2007 ; 107 : 260 –3
Magder S. Central venous pressure monitoring. Curr Opin Crit Care 2006 ; 12 : 219 –27
Osman D, Ridel C, Ray P, Monnet X, Anguel N, Richard C, Teboul JL. Osman D, C Ridel, P Ray, Monnet X, N, Richard, C Teboul Anguel JL. Cardiac filling pressures are not appropriate to predict hemodynamic response to volume challenge. Crit Care Med 2007 ; 35 : 64 –8
Metheny NA, Clouse RE, Chang YH, Stewart BJ, Oliver DA, Kollef MH. Metheny NA, RE Clouse, Chang YH, Stewart BJ, DA Oliver, MH Kollef. Tracheobronchial aspiration of gastric contents in critically ill tube-fed patients: frequency, outcomes, and risk factors. Crit Care Med 2006 ; 34 : 1007 –15
Orozco-Levi M, Torres A, Ferrer M, Piera C, el-Ebiary M, de la Bellacasa JP, Rodriguez-Roisin R. Semirecumbent position protects from pulmonary aspiration but not completely from gastroesophageal reflux in mechanically ventilated patients. Am J Respir Crit Care Med 1995 ; 152 : 1387 –90 6.
Atkinson G, Nevill AM. G Atkinson, Nevill AM. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med 1998 ; 26 : 217 –38