Use of Capnograph in Breathlessness Patients

A STUDY ON THE USE OF CAPNOMETRY IN ACUTE DYSPNEIC PATIENT IN EMERGENCY DEPARTMENT HOSPITAL UNIVERSITI SAINS MALAYSIA 12TH. INTERNATIONAL CONFERENCE ON EMERGENCY MEDICINE SAN FRANCISCO, USA 3RD - 6TH APRIL 2008 AF Mamat (MD,MMed) 1, R Ahmad 2 (MD, Mmed) Nik HNA Rahman 3 (MBChB, MMed) (Emergency Physicians) 1 Accident & Emergency Department, Hospital Kuala Lumpur 2Lecturer in Emergency Medicine, Hospital Universiti Sains Malaysia 3 Head of Department of Emergency Medicine, Hospital Universiti Sains Malaysia Hospital Universiti Sains Malaysia, Kubang Kerian, 16150, Malaysia. Tel: 00609-766 3000, Fax: 00609-765 3370 Email: nhliza@hotmail.com

INTRODUCTION
After pain and fatigue,dyspnea is the third most common presenting symptom in internal medicine (Mahler et al., 1996).
It is important to perform a thorough examination, including objective as well as subjective measures.
Assessment of cardiopulmonary status is a must in every patient presented with dyspnea.
Monitoring and evaluation require a device that can provide information regarding the respiratory, cardiovascular and also metabolic status of patient.

INTRODUCTION
Traditionally the pulse oxymetry and arterial blood gases is widely used to evaluate respiratory status of dyspneic patients.
But each of them has few significant disadvantages.
So in this study we were looking for an alternative method of monitoring acutely dyspnoeic patient namely capnometry.

Capnography
Recording of expired (end tidal) carbon dioxide (ETCO 2 ) concentrations plotted over time
Use to confirm and verify endotracheal tube placement, monitor ventilatory status of respiratory impaired patients, monitor ventilation of patients during sedation/analgesia, evaluate ventilator settings and circuit integrity, assess effectiveness of cardio-pulmonary resuscitation, and for early detection of changes in airway resistance
Yaron M, Padyk P, Hutsinpiller M, Cairns CB. (1996). Utility of Expiratory Capnogram in the Assessment of Bronchospasm. Ann Emerg Med 1996; 28: 403-407 INTRODUCTION 1

INTRODUCTION
In recent years ,capnometry has emerged as a useful measure of carbon dioxide tension in intubated patients.
Capnometry provides clinicians with a noninvasive measure of several dynamic system in the body: systemic metabolism, the circulatory system (cardiac output ) and blood flow to the lung ,and the ventilatory system.
The difference between P a CO 2 and ETCO 2 has been shown to be only 1-2 mmHg in healthy subjects with normal lung and uncompromised pulmonary functions.
However the utility and accuracy of portable capnometers in non-intubated patient has not been fully examined.

INTRODUCTION
Patients arriving in the emergency department (ED) with acute dyspnea need rapid and reliable evaluation of their respiratory status.
Microstream (sidestream) nasal prong ETCO 2 might be a non-invasive, rapid, and reliable predictor of arterial P a CO 2 in non-intubated patients in respiratory distress.
Determination are rapid , inexpensive ,and noninvasive and may obviate the need for arterial blood gasses in selected groups of patients .

STUDY OBJECTIVES
To determine correlation between ETCO 2 and P a CO 2 in non-intubated acute breathlessness patients.
To evaluate the correlation between ETCO 2 and P a CO 2 in certain acid base imbalance conditions

METHODOLOGY
A cross sectional study on acute breathlessness patients presented to Emergency Department for a period of 6 months.
The study was conducted in The Emergency Department of Hospital University Sains Malaysia (HUSM) with ethical committee approval.
Partial requirement for Master degree in Emergency Medicine.
Written & verbal (for distress/confused patient) informed consent.

METHODOLOGY
INCLUSION CRITERIA
1. Adult patients.
2. Conscious, alert and well orientated patients.
3. Non-intubated patient .
4. Presented with acute dyspnea .
EXCLUSION CRITERIA
1. Pediatric patients.
2. Patient that needed high concentration of oxygen therapy (Spo2<91% ).
3. Intubated patient .
4. Reduced level of consciousness (GCS <15) or unconscious patient .
5. Patient with shock systolic Blood pressure <90 mmHg or diasolic<60 mmHg.
6. Patients who did not require blood gas analysis

METHODOLOGY
Patients follow the dept. protocol for triage and registration
All patients with a chief complaint of shortness of breath with other inclusion criteria would be consented.
Treatment zones according to triage findings.
Doctor and nurses performed routine investigations .

METHODOLOGY
Adult duo-port oral/nasal oxygen (O 2 ) and CO 2 sampling canulla (micostream Capnoline ) was placed in the nostrils and over the mouth.
The nasal prong was attached to Datascope ® monitor combined microstream ETCO 2 analyser and pulse oxymeter .
3 ETCO 2 readings were recorded over duration of 3 minutes.
Arterial blood gas was taken & analyzed using Radiometer ® ABL 700 series - available in the ED .
All other data related to shortness of breath was recorded
(diagnosis, type of acid base imbalance)

METHODOLOGY

METHODOLOGY
Estimation of sample size was calculated using PS software using Regression 1 –based on the study done by Christopher W Barton: n=150 (after 10% drop out) BUT this study had recruited 165 patients.
Patients were grouped as having a primary acidosis ,alkalosis or normal using acid base normogram or as hypocapnic if PaCO 2 was less than 40 mmHg and hypercapneic if PaCO 2 was more than 40 .
Patient was also grouped into pulmonary and non-pulmonary pathology based on diagnosis from EDHUSM .
Correlation between P a CO 2 and ETCO 2 was analysed using bivariate pearson’s correlation for all variables .
All the parameters were entered into the study proforma analysed using SPSS 12.0 licensed to HUSM .

RESULTS 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-90 Age group (years) Percentage mean age of 54.19 and SD of 17.38 years There were 100 males (66.7%) and 50 females (33.3%) in this study

Hypertension Heart disease Asthma/COAD Diabetes mellitus None Types of premorbid condition Percentage Percentage Red Yellow Green (Triage Category) RESULTS

Other investigations done on patients RESULTS 23 34 Urine analysis 8.7 13 Abdominal Radiograph (AXR) 39 58 Echocardiography (ECHO) 12 18 Abdominal Ultrasound 97 146 Chest radiograph (CXR) 90 135 Blood tests 98.7 148 Electrocardiogram (ECG) Percentage (%) patients (n) Investigations 8 12 Painkiller drugs 16 24 Central Venous line 44.7 67 Bronchodilator drugs 18 27 Steroids 6.7 10 insulin 12.7 28 Inotrope drugs 41.3 62 Diuretic drugs 24.4 54 Sedative drugs 32 48 Iv isoket 59.3 89 Urinary catheter 100 150 Intravenous lines/drips 100 150 Oxygen(O2) Percentage (%) Patients (n) Treatment and therapeutic interventions

RESULTS Diagnosis or etiology of dyspnoea in study population 100 150 Total 6.7 10 Functional (hyperventilation,anxiety) 0.7 1 Poisoning 2.7 4 Hematology disorder 1.3 2 Epilepsy 2.7 4 Diabetic ketoacidosis 6 9 Sepsis 10.7 16 Cerebrovascular accident 4 6 Chest trauma 14 21 Pneumonia 25.3 38 Acute Coronary Syndrome 12.7 19 Asthma 13.3 20 Acute Pulmonary edema Percentage (%) Number of patients Causes of Dyspnoea

RESULTS significance level of p<0.05 0.005 0.370 0.074 30.4(6.95) 32.6(11.4) 29 Temperature (febrile) 0.113 0.000 0.336 29.5(7.5) 31.8(7.3) 107 Nonpulmonary 0.113 0.000 -.336 31.0(10.3) 40.3(16.6) 43 Pulmonary 0.544 0.000 -.738 36.8(11.5) 50.3(13) 32 Hypercapnia 0.544 0.000 0.738 28.1(6.2) 29.9(5.4) 118 Hypocapnia 0.029 0.037 0.171 27.9(6.3) 30.2(7) 28 Alkalosis 0.062 0.02 -.248 29.5(13.4) 40.6(21.8) 25 Acidotic 0.512 0.000 0.716 29.9(8.4) 34.3(11.4) 150 All r 2 P Perason correlation ETCO2 PCO2 N tests Metabolic disturbances

DISCUSSION
Cardiorespiratory disease is the leading cause of death & the second cause of admission to the hospital in Malaysia
Breathlessness is probably the second most common presentation in the ED after acute pain.
Commonly the sensation of breathlessness is related to some extent to derangement of respiratory, cardiovascular & metabolic status. (80% is related to the cardiorespiratory conditions in this study)
Hence we need a method of monitoring that could assess respiratory or cardiovascular or metabolic status

DISCUSSION
Commonly the breathing difficulty is associated with altered P a CO 2 (hyper or hypocapnia)- all patients in the study (78% hypo & 22% hyper)
We have attempted to use capnometry (ETCO 2 ) to find the correlation between the ETCO 2 reading & P a CO 2
Overall there is a strong correlation between the P a CO 2 & the ETCO 2 as we hypothesised
Interestingly there is a stronger correlation between the ETCO 2 & the hypocapnic state in which we postulated that the hypercapnic state is usually associated with parenchymal lung disease which interferes the capnometry function (gas exchange)

DISCUSSION
Similary the ETCO 2 showed a more positive correlation with non-pulmonary disease which we also postulated that the pulmonary parenchymal disease interferes with capnometry function
We also attempted to correlate the acid base status with the ETCO 2
Very interestingly the acidotic state (respiratory & metabolic) showed negative correlation with ETCO 2 compared to the alkalotic state.
Metabolic acidosis state i.e DKA results in hyperventilation state and hence hypocapnic condition

CONCLUSION
There is strong correlation between ETCO 2 and PaCO 2 in non intubated acute breathlessness patient
This study shows that ETCO 2 can be used to predict PaCO 2 level especially in the case of alkalotic and hypocapnic states
However the usage of ETCO 2 to predict PaCO 2 should be done with caution especially in cases that involve in pulmonary disorder
We could only mention that ETCO 2 is applicable & has a potential as a form of non invasive cardiopulmonary monitoring in non intubated acute breathlessness patient

REFERENCES Barton C.W & Wang ESJ. (1994). Correlation of End Tidal CO 2 measurements to arterial PaCO2 in non intubated patients. Annals of Emergency Medicine 23, 145 Chan KL, Chan MT & Gin T (2003). Mainstream vs. sidestream capnometry for prediction of arterial carbon dioxide tension during supine craniotomy. Anaesthesia 58, 149-155 Ferrin MS & Tino G (1997). Acute dyspnea. AACN Clin Issues 8, 398-410 G scano & Ambrosian N (2002). Pathophysiology of dyspnea. Lung 180 Ingram RH (1987). Effects of airway versus arterial CO 2 changes on lung mechanics. J Appl Physiol, 603-608 Raemer D Francis D & Philip J (1983). Variation in PCO 2 between arterial blood and peak expired gas during anaesthesia. Anaesth Analg 62, 1065-1069 Sanders AB (1989). Capnometry in emergency medicine. Ann Emerg Med 18, 1287-1290

Use of Capnograph in Breathlessness Patients

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