Nghiên cứu áp dụng kỹ thuật thông khí áp lực dương liên tục boussignac (CPAP b) trong xử trí trước bệnh viện khó thở cấp cứu luan án tom tat (english)

Concept of emergency dyspnea Emergency dyspnea is defined as the newly onset or acute on chronic of uncomfortable breathing arising within 24 to 48 hours and accompanied by “warning sig

This Dissertation will be defended in front of Dissertation committee

of the Institute at: date: / /

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2 Library of 108 Institute of clinical medical and pharmaceutical sciences

RATIONAL AND JUSTIFICATION

Emergency dyspnea is a common pathologic presentation in hospital setting, about 25% of total cases on ambulances [18] This may be a sign of life threatening condition, especially with warning signs such as altered mental status, respiratory failure, unstable hemodynamic [9]

pre-General principles for approaching patient with emergency dyspnea include: Airway management, breathing support, circulation support Non-invasive ventilation, BiPAP, CPAP can be choices for emergency dyspnea patients with respiratory failure [5]

CPAP Boussignac (CPAP-B) is a non-invasive ventilation device

it can generate continuous positive airway pressure which increase alveoli ventilation and oxygenation This is a simple, light weight, portable device that is convenient for using on ambulances [4] and it has been applied in pre-hospital setting in many countries with positive outcomes In Vietnam, no study on this device in pre-hospital care for patients with emergency dyspnea is found

3 Evaluation undesired effects during application of CPAP-B

CHAPTER 1 LITERATURE REVIEW 1.1 Emergency dyspnea

1.1.1 Concept of emergency dyspnea

Emergency dyspnea is defined as the newly onset or acute on chronic of uncomfortable breathing arising within 24 to 48 hours and accompanied by “warning signs” such as:

 Airway obstruction: wheezing, foreign body in the airway

 Respiratory failure, hypoxia, altered mental status, difficult speaking, using accessory muscles, respiratory muscles fatigue, tachypnea, pursed lips, diminishing breath sound one or both sides

 Unstable hemodynamic: chest pain, tachycardia, hypotension

 Reduced oxygen saturation [16,18]

Those warning signs along with emergency dyspnea required immediate critical interventions for saving patient’s life, and those signs are also significant for making diagnosis [26]

1.1.2 Principle of emergency dyspnea management in the hospital setting

pre-Emergency dyspnea is a life-threatening situation, in the context

of pre-hospital care, Management of cases with emergency dyspnea focus to airway assessment, breathing and circulation support in order

to secure patient life and safe transport to hospitals

1.2 CPAP Boussignac (CPAP-B)

1.2.1 Mechanism of action

CPAP-B is a non-invasive ventilation support device It generates airway continuous positive pressure from oxygen flow That helps improve alveoli ventilation and oxygenation Mechanism of action of CPAP-B is based on principle of Bernoulli The air flow from a larger

diameter pipe to a smaller diameter one is accelerated to the speed of sound The interference of those air flow within Boussignac valve creates a turbulent flow which in turn working as a virtual valve generates positive pressure toward patients

1.2.2 Indication: Acute respiratory failure because of [24]

- Acute pulmonary edema - Post-operation patients

- Acute COPD exacerbation - Asthma attack

- Sleep apnea

1.2.3 Contraindication: [24]

- Cardiac arrest - Active vomiting, aspiration risk

- Systolic pressure < 90 mm Hg - Serious Chest trauma

- Agitation, un-cooperation - Inability to protect airway

- Dyspnea due to

neuro-muscular conditions

- Profuse secretion or coughing inability

1.2.4 Effectiveness of CPAP-B for management respiratory failure

in the prehospital setting

Templier studied 57 patients with acute pulmonary edema those who were applied CPAP-B in pre-hospital setting The result shown that this device helped improving respiratory rate and SpO2

significantly [29] D.T Wong revealed that CPAP-B helped not only improving SpO2 and respiratory rate significantly but also reduced intubation rate down to 20% [31] Research of Eva Eiske Spijker et al gave similar positive results [19]

Thomas Luiz (2016) applied CPAP-B for 57 patients with respiratory failure in the pre-hospital setting, including of 35 patients with acute pulmonary edema and 22 patients with COPD The result revealed that respiratory rate, oxygenation was improved similarly between two group but the intubation rate in acute pulmonary edema group was higher than COPD group (17.1% vs 4.5%) [30] This result was similar to a study of Willi Schmidbauer 2010 [27]

In Vietnam, up to date, There is no research on the effectiveness

of CPAP-B applying on ambulances or in the pre-hospital setting

1.2.5 Undesired effects of CPAP Boussignac

Since 2009, John Bosomworth had found some undesired effects of CPAP-B such as:

- Pain or ulcer over the nasal bridge - Mucosal dryness

- Pneumothorax (very rare) - Fear of closed space

- Aspiration or gastric insufflation (rare) - Eye irritation

However this author did not mention which side effect was the most common as well as the rate of each side effect or what kind of patient with what kind of problem [24] Eva Eiske Spijker (2013) conducted a study to assess effectiveness and related complication of CPAP-B when applying for patients with acute pulmonary edema in the pre-hospital setting The result shown that this device was safe and had no complication [19] Similarly, Thomas Luiz et al (2016) announced that “CPAP-B can be used safely and effectively in the pre-hospital setting for patients who suffering from acute pulmonary

edema and COPD” [30]

CHAPTER 2 METHODOLOGY 2.1 Target population

All patients with emergency dyspnea, those who were provided hospital care and transported to hospital by 115 Hanoi Emergency Center from January 2015 to December 2015

pre-2.1.1 Eligible criteria

Patient was recruited to this research when they had newly onset

or acute on chronic of dyspnea arising within 24 to 48 hours and accompanied by at least one of following symptom:

 Unstable hemodynamic: chest pain, tachycardia, hypotension

 Reduced oxygen saturation [16,18]

 Tachypnea with respiratory rate ≥ 25 breath/min; or accessory muscle breathing or paradoxical abdominal movements

 Cyanosis; or SpO2 < 95 %

 Tachycardia: heart rate > 100 beat/min

AND SpO2 < 95 % after 5 minutes on oxygen therapy with 5 liter per minute via face mask or nasal cannula

2.1.2 Exclusion criteria

Any patient with at least one of following criteria:

 age < 18

 uncooperative patients

 contraindication with non-invasive ventilation

 Pneumothorax without chest decompression

 Open chest injury

 Abnormal or any trauma of facial structure

 Foreign body of upper airway is suspected

 Systolic Blood pressure < 90 mmHg

 Respiratory rate <10 breath/min

 Glasgow score < 8 or at U level (on AVPU scale)

C : constant; C = 19,84 with  = 0,01;  = 0,05

r : relative risk, estimated equal 0,6

ES: Effect size: ES = d /s

d was average difference of SpO2 before and after intervention (estimated 5%), s was standard deviation (estimated 5%) [10,32]

2.2.3 Interventional process

At the scene, pre-hospital staffs took patient’s medical history, chief complain and clinical assessment In case of emergency dyspnea was detected, patient was put on oxygen therapy via face mask or nasal cannula After 5 minutes, all unresponsive cases (SpO2 < 95% with 5 liter/min) were applied CPAP-B for breathing support Portable monitor was also attached for SpO2 and heart rate monitoring CPAP level was initiated at 5 cm water, increasing every 2.5 cm water by adjusting oxygen flow in order to maintain SpO2 ≥ 95% Maximum CPAP level was 10 cm water Those patients with CPAP-B whose signs and symptoms got worse during intervention process such as more severe respiratory, unstable hemodynamic, SpO2 < 95% with CPAP of 10 cm water or having any risk of complication such as vomiting, pneumothorax, aspiration must be terminated the CPAP-B therapy for other emergency procedures such as: intubation, larynx mask airway, AMBU On arrival at the Emergency room, CPAP-B

therapy could be ended for other intervention depend on the indication

of physician in charge there Two samples for arterial blood gas analysis were taken before and after using CPAP-B

2.2.4 Research variables

- General characteristics of target population: Age, gender, medical

history, time of service, duration of intervention

- Clinical characteristics of patients with emergency dyspnea: Level of

consciousness, signs and symptoms of respiratory failure, vital signs

- Characteristics of arterial blood gas of patients with emergency dyspnea: pH, PaO2, PaCO2, HCO3-

- Interventional result and related undesired effects:

 Success rate

 Comparison clinical, vital signs changes before and after intervention

 Comparison arterial blood gas before and after intervention

 Proportion of undesired effects related to CPAP-B

2.2.5 Research criteria

Level of consciousness:

In pre-hospital setting, we applied AVPU scale to assess level of consciousness [25]

Diagnoses in pre-hospital setting:

In this research, we used clinical practice guideline of Queensland ambulance service Queensland Australia [12,13,14,15] for diagnosis

of respiratory failure and its causes In the pre-hospital setting, those diagnoses mainly based on clinical signs and symptoms

Respiratory failure classification: criteria of Allal 2012 [8]

Success criteria (all following:)

 SpO2 maintained above 95%

 Heart rate reduction > 20%

 Stable hemodynamic

 Respiratory rate < 25 breath/min

 Improving clinical signs and symptoms [3,7]

Failure criteria (one or more of following)

 Worsen respiratory failure lead to termination of therapy and deploying other methods for breathing support such as intubation, laryngeal mask airway, AMBU

 Unstable hemodynamic

 SpO2 < 95% with CPAP level up to 10 cm water

 Uncooperation or appearance of related complications lead to termination of therapy[3,7]

2.3 Statistical analysis

Data was analyzed by medical statistic methods Mean,

standard diviation was performed as X ± SD (standard distribution)

or as median, quartile (non-standard distribution) Percentage was compared by χ2 test (or Fisher test) Mean of two independent groups were compaired by t - test (standard distribution) or Mann-Whitney test (non-standard distribution) Paired-t-test (standard distribution)

or Wilcoxon (non-standard distribution) was used for before – after comparison One way ANOVA test (standard distribution) and Kruskal-Wallis test (non-standard distribution) was for comparison

of multiple means p value < 0,05 was consider statistical significance

CHAPTER 3 RESULT 3.1 General characteristic of target population

 There were 150 patients enrolled in this study, mean of age was 73.5 ± 14.7 year old, youngest was 22, oldest was 97 year old There were more male than female, gender proportion of male over female was 2.26:1 aproximately

 Time of service was similar between day time (6h-18h) and night time (18h-6h) Average duration of care from on-scene to hospotal was 29.5 ± 11 minutes, minimum was 10 minutes, maximum was

66 minutes 68.7% patients was transported within 11 to 30 minutes

 In this research, there were 5 causes of emergency dypsnea They were pneumonia (53 patients, 35.3%), acute COPD exacerbation (44 patients, 29.3%), pulmonary edema (31 patients, 20.7%), asthma attack (18 patients, 12.0%), 4 patients (2.7%) with prior diagnosis of lung cancer

3.2 Characteristics of clinical manifestation and ABG of emergency dyspnea patients

3.2.1 Characteristics of clinical manifestation

Table 3.5 Level of consciousness

Level of consciousness n Percentage

Comment: 19.3 % patients altered mental status, no patient had U

level on AVPU scale

Comment: Only 30% patients had diaphoresis

Table 3.9 Paradoxical abdominal movements

Paradoxical abdominal movements n Percentage

Table 3.10 Accessory muscle breathing

Comment: Most of patients had sign of accessory muscle breathing

Table 3.11 Level of clinical respiratory failure

Clinical respiratory failure n Percentage

Comment: All patients with emergency dyspnea had respiratory

failure clinically at different level, mostly level II (73.3%)

3.2.2 Vital signs of patients with emergency dyspnea

Table 3.13 Pre-intervention vital signs

Heart rate (beat/min) 125.2 ± 12.0 90 156

Respiratory rate (breath/min) 32.5 ± 5.3 20 56

Comment: Before intervention, heart rate, respiratory rate, blood

pressure increased, SpO2 decreased

3.2.3 Arterial blood gas of patients with emergency dyspnea

Table 3.14 Pre-intervention arterial blood gas

PaO 2 (mmHg) 150 60.98 ± 10.14 38.00 79.70

PaCO 2 (mmHg) 150 44.51 ± 13.55 20.10 82.20

HCO 3 - (mmol/L) 150 24.65 ± 4.84 13.20 37.10

Comment: PaO2 decreased, PaCO2 was at upper level of normal range

Table 3.15 Pre-intervention acid-base balance

Comment: 62% patients had acid-base imbalance prior intervention

3.3 Effectiveness of CPAP Boussignac in pre-hospital emergency dyspnea management

3.3.1 Clinical changes before and after intervention

Chart 3.5 Mental status changes before and after intervention

Comment: after intervention, mental status was improved significantly

p <0,01

Table 3.18 Cyanosis before and after intervention

Comment: there was no cyanosis in most of patient after intervention,

Table 3.19 Difficulty in taking before and after intervention

Pre-intervention

Talks in sentence 1 0.7 %

150 (100%)

Talks in phases 123 82.0 %

Comment: Taking ability’s improved significantly after intervention

Chart 3.7 Paradoxical abdominal movements before and after

Table 3.20 Accessory muscle breathing before and after

intervention

Phase Accessory muscle

breathing n Percentage Total p Pre-

Comment: Level of clinical respiratory failure was deducted

significantly after intervention

p < 0,01

p <0,01

Table 3.21 Vital signs before and after intervention

Variable Phase (𝐗 ̅ ± SD) Min Max p SpO 2

3.3.2 Arterial blood gas changes before and after intervention

Table 3.25 Arterial blood gas before and after intervention Variable Phase (𝐗 ̅ ± SD) Min Max p PaO 2

(mmHg)

Pre 60.98 ± 10.14 38.0 79.7

< 0.01 Post 110.70 ± 19.19 82.5 187.6

PaCO 2

(mmHg)

Pre 44.51 ± 13.55 20.1 82.2

< 0.01 Post 41.48 ± 9.76 19.6 69.9

HCO 3 -

(mmol/L)

Pre 24.65 ± 4.84 13.2 37.1

0.439 Post 24.62 ± 4.31 16.3 35.4

Post 7.40 ± 0.74 7.24 7.56

Comment: after intervention, PaO2, PaCO2, pH improved significantly

3.4 Result of CPAP-B therapy and related undesired effects Table 3.35 Result of CPAP-B therapy in pre-hospital setting