Colorimetric capnography, a new procedure to ensure correct feeding tube placement in the intensive care unit: An evaluation of a local protocol

Article (PDF Available)inJournal of critical care 26(4):411-4 · August 2011with87 Reads
DOI: 10.1016/j.jcrc.2010.08.007 · Source: PubMed
Abstract
Radiography is the criterion standard method to ensure correct placement of a feeding tube. Recently, excellent results were reported using a combination of colorimetric capnography and epigastric auscultation, but the impact of this technique has not been studied to date. Objectives were to assess whether our local procedure, using colorimetric capnography to ensure proper feeding tube placement, improves the patient's care, satisfies nurses, and decreases costs compared with the standard procedure requiring systematic radiography. We performed a monocentric prospective observational study in a medical intensive care unit over a 4-month period. Feeding tube placement was assessed by colorimetric capnography and epigastric auscultation. Radiography was performed when epigastric auscultation was inconclusive. A total of 69 feeding tubes were placed in 44 patients. Radiography was required in 10.1% of the cases. The new procedure decreased costs ($33.37 ± 13.96 vs $45.92, P < .0001) and was less time consuming (11.6 ± 20.5 minutes vs 87.3 ± 45.2 minutes, P < .0001) than using systematic radiography. All nurses reported confidence in the procedure, which improved the organization of their care. The use of colorimetric capnography and epigastric auscultation to confirm feeding tube placement improves nurse's organization of care, saves time, and decreases costs.
Procedures
Colorimetric capnography, a new procedure to ensure
correct feeding tube placement in the intensive care unit:
An evaluation of a local protocol
Arnaud Galbois MD
a,b,
, Paola Vitry RN
a
,
Hafid Ait-Oufella MD, PhD
a,b
, Jean-Luc Baudel MD
a,b
,
Bertrand Guidet MD
a,b,c
, Eric Maury MD, PhD
a,b,c
, Georges Offenstadt MD
a,b,c
a
Service de Réanimation Médicale, Hôpital Saint-Antoine (AP-HP), 184 rue du faubourg Saint-Antoine, 75571,
Paris Cedex 12, France
b
Université Pierre et Marie Curie (Paris VI), France
c
INSERM, UMR S-707, 75012, Paris, France
Keywords:
Enteral nutrition;
Intensive Care Unit;
Capnography
Abstract
Purpose: Radiography is the criterion standard method to ensure correct placement of a feeding tube.
Recently, excellent results were reported using a combination of colorimetric capnography and
epigastric auscultation, but the impact of this technique has not been studied to date. Objectives were to
assess whether our local procedure, using colorimetric capnography to ensure proper feeding tube
placement, improves the patient's care, satisfies nurses, and decreases costs compared with the standard
procedure requiring systematic radiography.
Material and Methods: We performed a monocentric prospective observational study in a medical intensive
care unit over a 4-month period. Feeding tube placement was assessed by colorimetric capnography and
epigastric auscultation. Radiography was performed when epigastric auscultation was inconclusive.
Results: A total of 69 feeding tubes were placed in 44 patients. Radiography was required in 10.1% of the
cases. The new procedure decreased costs ($33.37 ± 13.96 vs $45.92, P b .0001) and was less time
consuming (11.6 ± 20.5 minutes vs 87.3 ± 45.2 minutes, P b .0001) than using systematic radiography. All
nurses reported confidence in the procedure, which improved the organization of their care.
Conclusions: The use of colorimetric capnography and epigastric auscultation to confirm feeding tube
placement improves nurse's organization of care, saves time, and decreases costs.
© 2011 Elsevier Inc. All rights reserved.
1. Introduction
Enteral nutrition (EN) is the preferred method of
nutritional support for patients admitted to intensive care
units (ICUs). It should be started within the first days of
admission [1]. Accidental placement of an enteral feeding
Abbreviations: ICU, intensive care unit; EN, enteral nutrition;
EFT, enteral feeding tube; CC, colorimetric capnography.
Institution where the work was performed: Service de Réanimation
Médicale, Hôpital Saint-Antoine (AP-HP), 184 rue du faubourg Saint-
Antoine, 75571, Paris Cedex 12, France.
Corresponding author. Tel.: +33 9 52 78 30 51, +33 1 49 28 23 18
(work); fax: + 33 1 49 28 26 92.
E-mail address: galbois@gmail.com (A. Galbois).
0883-9441/$ see front matter © 2011 Elsevier Inc. All rights reserved.
doi:10.1016/j.jcrc.2010.08.007
Journal of Critical Care (2011) 26, 411414
tube (EFT) in the tracheobronchic airway can lead to
potentially lethal complications [2-4]. Tracheal intubation
of patients in ICU does not always prevent this
misplacement [5]. Ensuring correct EFT insertion is
therefore of paramount importance f or ICU patients.
Confirmation of EFT placement by epigastric auscultation
of air injected through the EFT is not a reliable test when
used alone [6-8]. Some groups have suggested testing the
pH of an aspirate obtained from the EFT to ensure proper
placement, but this test can be inconclusive in patients
with small-bore EFT or those on acid suppression [6].
Therefore, most guidelines recommend confirming EFT
placement by radiography before beginning EN [8-10].
However, a multicenter study recently performed in France
showed that x-rays are overprescribed and could b e
reduced [11]. We recently proposed a new method of
ensuring correct EFT placement by combining colorimetric
capnography (CC) and epigastric auscultation [12]. This
procedure predicts the gastric position of the EFT with
perfect specificity, even if supplemental radiographs are
required in cases of inconclusive auscultation [12]. The
potential requirement for radiography after CC could have
diminished potential interest in this procedure because it
requires more time and increases the cost of the procedure.
This procedure is now recommended in our ICU. We
conducted this study to assess whether this procedure
improves the patient's care, satisfies nurses, and decreases
costs in real-life.
2. Material and methods
2.1. Design
This was a monocentric prospective observational study
conducted from May to August 2009 in a 14-bed medical
ICU in a tertiary teaching hospital. All cases involving EFT
insertion were included in the study.
2.2. Confirmation of EFT placement using CC
The CC device used (Easycap II; Nellcor-Puritan Bennet,
Inc, distributed by Tyco, Plaisir, France) displays different
colors according to ranges of CO
2
concentration (purple:
CO
2
b4 mm Hg; brown: CO
2
between 4 and 15 mm Hg;
yellow: CO
2
N15 mm Hg). This CC device has been
elaborated to ensure tracheal tube placement after intubation,
and it is not fitted for a connection to an EFT. We attached
the CC device to the EFT (CAIR LGL, Civrieux d'Azergue,
Rhône, France) via the tip of an endotracheal tube (Portex
Tracheal Tube). Methods for using the CC were derived from
the initial study [12]. Briefly, the EFT was inserted to a depth
of 30 cm from the nostril. The operator checked first that it
was not coiled in the pharynx, and then the guide wire was
pulled out. The nurse assessed the permeability of the tube by
insufflation and exsufflation of air with a 50-mL syringe. The
CC device was then connected to the EFT. The procedure
was continued as follows according to the color displayed by
the CC device. If the CC remained purple, the guide wire was
replaced, and the tube was inserted to a total depth of 50 cm.
If the CC color changed to yellow or brown, the EFT was
withdrawn and the procedure was started again. Following
CC detection, the operator performed epigastric auscultation
after air insufflation. If gurgling was heard, EN was started
immediately. If the auscultation was inconclusive, bedside
radiography was required to assess EFT placement.
2.3. Measurements
We recorded the total number of radiographs required and
the time from the beginning of EFT placement to the onset of
EN. The final costs to confirm EFT placement were
calculated. Our institution bought each CC device and
endotracheal tube to the manufacturer for $22.78 and $5.95,
respectively. The cost of a bedside radiography evaluated by
our institution was $45.92. Thus, the cost to confirm EFT
placement was $28.73 with CC alone ($22.78 + $5.95) and
$74.65 when a bedside radiography was required ($22.78 +
$5.95 + $45.92). Each nurse was given an anonymous
questionnaire with 5 items to assess their opinion about
this procedure.
2.4. Statistics
Results are expressed as n (%) or mean ± SD. The time
elapsed between the beginning of the procedure and the
onset of EN was compared with the time required for the
procedure involving systematic use of radiography
(recorded during the previous 4-month period) by the
Student t test.
3. Results
3.1. Patients and EFT
During the 4 months of the study, 314 patients were
admitted to our ICU. A total of 69 EFTs were inserted in 44
Table 1 Characteristics of patients in whom the EFTs
were inserted
Altered
consciousness
Total
Yes No
Placed under
mechanical
ventilation
Yes 34 14 48
No 5 16 21
Total 39 30 69
412 A. Galbois et al.
patients (age, 66.5 ± 15.3 years; male, n = 26 [59.1%];
Simplified Acute Physiology Score II, 51 ± 16; length of stay
in ICU, 13.4 ± 15.8 days). The reasons for admission were as
follows: acute respiratory failure (n = 21, or 47.7%), coma
(n = 12, or 27.3%), shock (n = 6, or 13.6%), acute renal failure
(n = 4, or 9.1%), and acute liver failure (n = 1, or 2.3%). The
mean (SD) number of EFTs per patient during their ICU stay
was 1.7 (0.9). Most of the EFTs was inserted in patients
receiving mechanical ventilation and/or with altered con-
sciousness (Table 1).
3.2. Radiography requirement to confirm
EFT placement
Methods used to confirm EFT placement are summarized
in Table 2. Combining CC and epigastric auscultation was
able to confirm the gastric position of EFT without requiring
radiography in 89.9% of cases.
3.3. Impact of CC to ensure correct EFT placement
Comparing this procedure with systematic use of
radiography to confirm EFT placement, CC and auscultation
decreased costs ($33.37 ± 13.96 vs $45.92 P b .0001) and
saved time (11.6 ± 20.5 minutes vs 87.3 ± 45.2 minutes, P b
.0001). All the 30 nurses working in the ICU answered the
questionnaire, and every one reported that CC was easy to
perform. Among them, 87% were confiden t in the
combination of CC and epigastric auscultation, 93% were
satisfied with this procedure, 93% thought that using CC
simplified the organization of patient's care, and none would
have preferred to give up this procedure in favor of
systematic radiography.
4. Discussion
The main results of this study are that using CC to confirm
EFT placement improves the patient's care by saving time,
satisfies nurses, and decreases costs.
In the original study [12], a lack of CC color change when
the EFT was inserted to 30 cm (after ruling out that it was
coiled in the oropharynx) confirmed that the tube was in the
esophagus. The authors concluded that after the EFT was
inserted to 50 cm, epigastric auscultation was still needed to
ensure that the tube was not coiled in the esophagus. Thus, if
epigastric auscultation was inconclusive, radiography was
required. The potential requirement for radiography after CC
could have diminished potential interest in this procedure
because it requires more time and increases the cost of the
procedure. However, this study shows that in practice, use of
CC saves both time and money.
This procedure improves patient's care. Even though it is
advisable to begin EN shortly after admission to the ICU [1],
saving 80 minutes will m ost likely not affect patient
outcomes. However, with CC, nurses can start EN
immediately after EFT insertion. The procedure is performed
in one time, avoiding the delay for the radiography. This
delay, sometimes very long, could be responsible of an
omission, especially when the workload is heavy. Nurses
expressed great satisfaction with CC and reported that this
saved time improved the organization of patient's care,
which is one of the clear advantages of this procedure.
Use of CC saved an average of $12 per EFT insertion,
resulting in savings of $2500 in 2009 in our ICU. This
economy is even above the cost of one EFT ($10.15).
Although examining the efficacy of this test was not a
goal of this study, all the 4 accidental EFT insertions in the
airway were diagnosed before starting EN, and all of them
were correctly inserted in the next attempt. The EFT and CC
device were the same models as in the initial study [12].
Because EFT permeability is essential for CC color
modification in the case of accidental EFT insertion in the
airway, if groups wish to use CC with other small-bore
EFT models, this technique should be validated for
their equipment.
5. Conclusion
The use of CC and epigastric auscultation, to confirm
feeding tube placement, improves nurse's organization of
care, saves time, and decreases costs.
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Table 2 Methods used to confirm EFT placement
Radiography
required
n (%) Cost per
confirmation
of EFT
placement ($)
Time required per
confirmation
of EFT
placement (min)
No 62 (89.9) 28.73 5.5 ± 3.2
Yes 7 (10.1) 74.65 65.1 ± 30.7
Total 69 (100) 33.37 ± 13.96 11.6 ± 20.5
413Colorimetric capnography ensure correct feeding tube placement
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414 A. Galbois et al.
    • "Several methods have been suggested for verifying the placement of a NGT, including auscultation, measuring the pH of aspirates from the tube, and chest x-rays. In addition, the use of colorimetric capnography has been demonstrated recently [5,6]. Auscultation with a stethoscope confirms gurgling sounds in the epigastrium when air is injected after NGT insertion. "
    [Show abstract] [Hide abstract] ABSTRACT: This study was designed to compare the effectiveness of using auscultation, pH measurements of gastric aspirates, and ultrasonography as physical examination methods to verify nasogastric tube(NGT) placement in emergency room patients with low consciousness who require NGT insertion. The study included 47 patients who were all over 18 years of age. In all patients, tube placement was verified by chest X-rays. Auscultation, pH analysis of gastric aspirates, and ultrasonography were conducted on each patient in random order. The mean patient age was 57.62 ± 17.24 years, and 28 males (59.6%) and 19 females (40.4%) were included. The NGT was inserted by an emergency room resident. For pH testing, gastric aspirates were dropped onto litmus paper, and the resulting color of the paper was compared with a reference table. Ultrasonography was performed by an emergency medicine specialist, and the chest X-ray examination was interpreted by a different emergency medicine specialist who did not conduct the ultrasonography test. The results of the auscultation, gastric aspirate pH, and ultrasonography examinations were compared with the results of the chest x-ray examination. The sensitivity and specificity were 100% and 33.3%, respectively, for auscultation and 86.4% and 66.7%, respectively, for ultrasonography. Kappa values were the highest for auscultation at 0.484 compared to chest x-rays, followed by 0.299 for ultrasonography and 0.444 for pH analysis of the gastric aspirate. The ultrasonography has a positive predictive value of 97.4% and a negative predictive value of 25%. Ultrasonography is useful for confirming the results of auscultation after NGT insertion among patients with low consciousness at an emergency center. When ultrasound findings suggest that the NGT placement is not gastric, additional chest X-ray should be performed.
    Full-text · Article · Jun 2012
    • "Radiography is required only when epigastric auscultation is inconclusive (10.1% of cases). This local protocol combining colorimetric capnography and epigastric auscultation had a perfect specificity to confirm correct EFT placement, improves nurse's organization of care, saves time, and decreases costs [34,35]. Another advantage of this procedure is that theFigure 2 Assessment of intragastric position of a small bore enteral feeding tube by ultrasonography [31]. "
    [Show abstract] [Hide abstract] ABSTRACT: Chest x-rays (CXRs) are the main imaging tool in intensive care units (ICUs). CXRs also are associated with concerns inherent to their use, considering both healthcare organization and patient perspectives. In recent years, several studies have focussed on the feasibility of lowering the number of bedside CXRs performed in the ICU. Such a decrease may result from two independent and complementary processes: a raw reduction of CXRs due to the elimination of unnecessary investigations, and replacement of the CXR by an alternative technique. The goal of this review is to outline emblematic examples corresponding to these two processes. The first part of the review concerns the accumulation of evidence-based data for abandoning daily routine CXRs in mechanically ventilated patients and adopting an on-demand prescription strategy. The second part of the review addresses the use of alternative techniques to CXRs. This part begins with the presentation of ultrasonography or capnography combined with epigastric auscultation for ensuring the correct position of enteral feeding tubes. Ultrasonography is then also presented as an alternative to CXR for diagnosing and monitoring pneumothoraces, as well as a valuable post-procedural technique after central venous catheter insertion. The combination of the emblematic examples presented in this review supports an integrated global approach for decreasing the number of CXRs ordered in the ICU.
    Full-text · Article · Mar 2011
  • [Show abstract] [Hide abstract] ABSTRACT: Chest-X-rays (CXR) are the most frequent imagebased explorations performed in intensive care units (ICUs). Indications and prescription modalities (whether routine or on demand prescription strategies) may substantially differ from an ICU to another. The observed heterogeneity reflects a substantial distance between clinical practice and official recommendations. Current guidelines recommend CXRs on a daily basis especially for patients receiving mechanical ventilation and/or suffering from acute cardio-pulmonary failure, whereas practice-based studies report that CXR prescriptions are mainly based on the clinical context. The recently published RARE study shows, with a reliable methodology, that prescribing CXR on demand rather than as a daily routine allows to reduce CXR prescription by 32% in patients receiving mechanical ventilation, with a better diagnostic and therapeutic efficiency and without any impairment of prognosis. Therefore, precise targeted prescription together with the use of reliable diagnostic alternatives (such as ultrasound) should result in a decrease in the number of CXRs performed in the ICU, in patients’ global irradiation, in diagnostic delays, and in costs. Considering current available data, guidelines for CXR prescriptions in the ICU should be updated.
    Full-text · Article · Jan 2010
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