Mechanical Ventilation

MECHANICAL VENTILATION

MECHANICAL VENTILATION

a positive or negative pressure breathing device that can maintain ventilation and oxygen delivery for a prolonged period.

used when patient is unable to maintain safe levels of oxygen or CO2 by spontaneous breathing even with the assistance of other oxygen delivery devices.

used to control patients respirations during surgery

to oxygenate blood when patients ventilator efforts are inadequate

to rest the respiratory muscle- pts may be spontaneous breathers but effort needed to to breathing maybe very exhausting for the patient

INDICATIONS:

continous decrease in O2, Increase PaCO2 persistent acidosis Conditions: thoracic, abdominal surgery, drug

overdose, neuromuscular disorder, inhalation injury

COPD, multiple trauma, shock, multi system failure and coma.=====all lead to respiratory failure

apnea

PARAMETERS FOR MECHANICAL VENTILATION

Pa O2 < 50mmhg with FiO2 > 0.60 PaO2 > 50 mmhg with pH < 7.25 Vital capacity < 2 times tidal volume RR > 35 cpm

CLASSIFICATIONS OF MECHANICAL VENTILATOR

NEGATIVE PRESSURE-exert negative pressure on the external chest, drawing air into the lungs

similar to spontaneous ventilation

Decreasing intrathoracic pressure during inspiration, allow air to flow into lungs, filling its volume

TYPES OF NEGATIVE PRESSURE

DRINKER RESPIRATORY(IRON LUNG)-

---extensively used for neuromuscular d.o. machine enables the person to breathe when normal muscle control has been lost or work of breathing exceeds person’s ability.

BODY WRAP (PNEUMOWRAP)--patient lies supine on the plate which extends the

length of the thoracic spine.-the grid is placed over the patients thorax and a

separate power source is connected to the mid portion of the suit by a plastic tube.

-The grid causes negative pressure generated with in the suit to be applied predominantly to the thorax since plastic is sucked tightly against all other body parts.

-only used on patients who are not totally dependent on ventilator support and generally only provides modest tidal volumes.

. CHEST CUIRASS (TORTOISE SHELL)-

consist of rigid shell, some consist of shells of either reinforced plastic or fiber glass which extend from symphysis pubis to supra sterna notch.

- Must be connected to a power source capable of generating -25 to -30 cmH2O pressure. Since the cuirass only covers the chest area, the patient can be ventilated in either the sitting or supine position.

POSITIVE PRESSURE-inflate the lung by exerting positive pressure on the airway, forcing the alveoli to expand during inspiration, expiration occurs passively

3 TYPES OF POSITIVE- PRESSURE VENTILATORS (CLASSIFIED BY THE METHOD OF ENDING THE INSPIRATORY PHASE OF RESPIRATION)

1.PRESSURE CYCLED 2. TIME CYCLED 3. VOLUME CYCLED

PRESSURE CYCLED-the ventilator cycles on, delivers a flow of air until a predetermined pressure is reached and then cycles off

TIME CYCLED-terminate or control inspiration after a preset time., for newborns, and infants

VOLUME –CYCLED- commonly used PPV, the volume of air to be delivered with each inspiration is preset. Once this preset volume is delivered to the patient, the ventilator cycles off and exhalation occurs passively.

MODES OF OPERATION

CONTROLLED VENTILATION ASSIST/CONTROL INTERMITTENT MANDATORY

VENTILATION SYNCHRONIZED INTERMITTENT

MANDATORY VENTILATION (SIMV) PRESSURE SUPPORT

CONTROLLED VENTILATION

1. Cycles automatically at rate selected by operator

2. Provides fixed level of ventilation, but will not cycle or have a gas available in the circuitry to respond to pts own inspiratory efforts. This typically increases work of breathing for patients attempting to breath spontaneously.

3. Possible indicated for patients whose respiratory drive is absent

ASSIST/CONTROL

Inspiratory cycle ventilator is activated by patients voluntary inspiratory efforts and delivers a preset volume or pressure.

Ventilators also cycles at a rate predetermined by the operator. Should the patient stop breathing, or breathe so weakly that the ventilator cannot function as an assistor, this mandatory baseline rate will prevent apnea.

Indicated for patients who are breathing spontaneously, but who have a potential to lose their respiratory drive or muscular control of ventilation. In this mode the persons work of breathing is greatly reduced.

INTERMITTENT MANDATORY VENTILATION

Allows patient to breathe spontaneously through ventilator circuitry.

Periodically, at pre selected rate and volume or pressure, cycles to give a mandated ventilator breath. A minimum level of ventilation is provided.

Gas provides spontaneous breathes usually flows continuously through the ventilator.

Indicated for patients who are breathing spontaneously , but a tidal volume and / or rate less than adequate for their needs. Allows a person to do some work of breathing.

SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV)

Allows the patient to breathe spontaneously through ventilator circuitry.

Periodically, at a pre- selected time, a mandatory breath is delivered with own effort and the ventilator breath will be synchronized with the patients efforts or will be assisted. If the patient does not provide inspiratory effort, the breath will still be delivered or controlled.

Gas provide for spontaneous breathing is usally delivered through a demand regulator, which is activated by the patient.

Indicated for patients who are breathing spontaneously, but a tidal volume and /or less than adequate for their needs. But allows the patient to do some breathing.

PRESSURE SUPPORT

Spontaneous breathing mode bec ventilator does not deliver a tidal volume or rate.

During spontaneous inspiration, ventilator circuitry is rapidly pressurized to the pre determined pressure and held at this pressure.

Decreases work of breathing by overcoming resistance of airway and ventilatory circuitry.

****** PEEP-(POSITIVE END EXPIRATORY PRESSURE)

A positive airway pressure maintained at the end of exhalation. This allows more time for gas exchange and opens small airways and closed alveolar units., thus improving oxygenation and a reduction in the severity of the ventilation perfusion imbalance.

A lower F1O2 is required.  

******* CPAP-( CONTINOUS POSITIVE AIRWAY VENTILATION)

Maintenance of a positive airway pressure above atmospheric pressure during inspiration and expiration in the spontaneously breathing client. It improves oxygenation in the same manner as PEEP

*******PEEP AND CPAP SETTINGS

Tidal volume- amount of air per breath, usually set at 10-15 ml/kg body weight

Respiratory rate-usually at 10-15 breaths per minute PEEP and /or pressure support level if applicable –usually 5 to 15

cm H2O FIO2-50% or less maintains an arterial oxygen pressure PaO2 of

greater than or equal to 60mmhg which is the goal of oxygenation.

Sensitivity a 2cm H2O inspiratory force should trigger the ventilator

Inspiratory pressure limit- normal is 15- 20 cm H2O, this increases where there is increased airway resistance or decreased compliance.

INSPIRATORY AND EXPIRATORY RATIO: usually 1:3 (1 Second of inspiration to 3 seconds of expiration) or 1:2

Minute volume (tidal volume x respiratory rate) usually 6 to 8 LPM  

ALARMS WITH NURSING INTERVENTIONS:a. LOW PRESSURE

ALARMCAUSE INTERVENTION

*sounds when the ventilator has no resistance to inflating the lung

1. Tube maybe disconnected2. E.T displaced above vocal

cords3. Leaking tidal volume from

cuff pressure(underinflated ruptured cuff or a leak in the cuff)

4. Ventilator malfunction5. Leak in the circuitry (loose

connection, hole in the tube, loss of temporary –sensitive device, cracked humidification jar)

1. Reconnect the tube to M.V2. Check tube placement reposition

if needed. If extubation/ displacement has occurred, manually ventilate the patient and call the doctor ASAP

3. Listen for a whoosing sound around the tube, indicating an air leak. If you hear ,check the cuff pressure. If you cannot maintain pressure,call doctor he may need to insert a new tube.

4. Disconnect the patient from the ventilator and ventilate him manually. If necessary get another M.V.

5. Make sure all connections are intact. Check for holes, leaks in the tubing and replace if necessary.

a. HIGH PRESSURE ALARM** ventilator has met resistance to deliver the tidal volume and requires more pressure to inflate the lungs

1. Increased airway pressure or decreased lung compliance caused by worsening condition

2. Pt. biting the oral E.T3. Secretions in airway4. Condensate in the

tubings5. Intubation of the right

bronchi6. Pt coughing, gagging

attempting to talk7. Chest wall resistance8. bronchospasm

1. Auscultate the lungs for evidence of increased lung consolidation, barotrauma, wheezing, call the doctor if indicated.

2. Insert a bite block3. Look for secretions, remove

them by suctioning.4. Check the tubing for

condensate, remove fluid. 5. Check tube positions,if it has

slipped, call the doctor, he may order

Reposition6. If patients fights the

ventilator, call the doctor he may order sedative.

7. Reposition the patient, to see if repositioning can improve the chest expansion.

8. Assess for cause and refer

WEANING PATIENT FROM MECHANICAL VENTILATOR

RESPIRATORY WEANING=WEANING THE PATIENT FROM DEPENDENCE ON VENTILATOR, USUALLY PERFORM EARLIEST POSSIBLE TIME, USUALLY DONE IF PATIENT IS RECOVERING FROM ACUTE STAGE OF MEDICAL SURGICAL PROBLEM AND WHEN RESPIRATORY FAILURE IS SUFFICIENTLY REDUCED. 

3 STAGES: 1. GRADUALLY FROM THE VENTILATOR 2. FROM THE TUBE 3. FROM THE OXYGEN

CRITERIA FOR WEANING

An ability to generate minimal vital capacity of 10-15 ml/ kg ( minimal required volume is in range of 1000ml in a normal adult)

Spontaneous inspiratory force of atleast -20 cm H2O

PaO2 of greater than 60 mmhg with an FIO2 less than .4o %

Stable vital signs ****note the following baseline measurements:

Vital capacity, Inspiratory force, respiratory rate, resting tidal volume, minute ventilation (frequency times volume) arterial blood gase levels, FiO2.

PATIENT PREPARATIONAdequate psychological preparation is necessary before and after weaning.

Proper preparation reduces time of weaning.

METHODS OF WEANING

TRADITIONAL METHOD SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV) METHOD

TRADITIONAL METHOD

Involves switching from assist control or SIMV mode to one or more T-Piece trials.

Usually used when there is short term ventilator assistance ( less than 2 days)

Done when pt is alert and awake,(during daytime not at night) breathing without difficulty, has good gag ,cough reflex and hemo dynamically stable.

The patient breathes spontaneously with aid of humidified oxygen

DURING WEANING: patient is maintained on same or higher O2 concentration than when on ventilator

WHILE ON T-PIECE: observe pt for s/sx of hypoxia, increasing fatigue

SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV) METHOD –INDICATED IF PATIENT SATISFIES ALL CRITERIA FOR WEANING BUT CANNOT SUSTAIN ADEQUATE SPONTANEOUS VENTILATION FOR LONG PERIODS.

**** pressure support – frequently used as an adjunct to SIMV weaning mode.

**pressure support provides- a set of inspiratory pressure boost with spontaneous breaths.

*pressure support gradually reduced as patients strength increases

WEANING FROM A TUBECRITERIA

Spontaneous ventilation is adequate gag reflexes are active Can maintain adequate airway can swallow, move jaw, clench the teeth or

voluntary cough is effective in bringing up secretions.

***if ineffective: Tube is needed for suctioning secretions

*** before a pt is weaned from T.Tube –a trial period of mouth breathing/nose breathing is conducted

WEANING FROM OXYGEN- THE FIO2 IS GRADUALLY REDUCED UNTIL THE PO2 IS IN RANGE OF 70- 100 MMHG WHILE PATIENT IS BREATHING ROOM AIR. IF THE PO2 IS LESS THAN 70 MMHG ON ROOM AIR, SUPPLEMENTAL O2 IS NECESSARY.

CENTRAL VENOUS PRESSURE MONITORING

measurement of right atrial pressure or pressure of the great veins within the thorax

requires the threading of a catheter into a large central subclavian, internal or external jugular, median or basilica or femoral vein.

Catheter tip is then positioned in the right atrium, upper portion of superior vena cava, or inferior vena cava.

PURPOSE OF CVP:

To serve as a guide for fluid replacement To monitor pressures of the right atrium

and central veins To administer blood products, TPN and

drug therapy contraindicated for peripheral infusion

To obtain venous access when peripheral vein sites are inadequate.

To insert a temporary pacemaker To obtain central venous sample.

MANUAL CENTRAL VENOUS PRESSURE MONITORING

PREPARATORY PHASE: (NURSE) Assemble equipment Explain procedure Position patient appropriately-Place in supine

for arm vein, Neck veins for trendelenburg’s position Flush IV infusion set and manometer or

prepare heparin flush for use with transducer . Secure all connections to prevent air emboli and bleeding.

Attach manometer to an IV pole. The zero point of manometer should be on a level with the patients right atrium ( level of atrium is at the fourth ICS midaxillary line.)

Calibrate/zero transducer and level port with the patients atrium.(mark mid axillary line with indelible ink for subsequent readings to ensure consistency of the zero level.)

Institute ECG

TO MEASURE CVP:

Place pt in position of comfortPosition the zero point of the

manometer at the level of the right atrium

Turn the stopcock so IV solution flows into manometer, filling to about 20-25 cm level. Then turn stopcock so solution in the manometer flows to the patient.

Observe the fall in the height of the column of fluid in the manometer. Record the level at which the solution stabilizes or stops moving downward. This is CVP. Record CVP and position the patient.

CVP may be connected to a transducer and an electrical monitor with either digital or calibrated CVP wave readout.

CVP may range from 5-12 cm H2O or 2 to 6 mmhg.

THANK YOU AND GOD BLESS

OB GYNECOLOGIC TEST AND PROCEDURES

PAPANICOLAOU TEST (ALSO CALLED PAP SMEAR, PAP TEST, CERVICAL SMEAR, OR SMEAR TEST)

screening test used in gynecology to detect premalignant and malignant (cancerous) processes in the ectocervix.

Significant changes can be treated, thus preventing cervical cancer.

The test was invented by and named after the prominent Greek doctor Georgios Papanikolaou..

a tool is used to gather cells from the outer opening of the cervix of uterus and the endocervix.

cells are examined under a microscope to look for abnormalities.

aims to detect potentially pre-cancerous changes : cervical intraepithelial neoplasia (CIN) or cervical dysplasia, which are usually caused by sexually transmitted human papillomaviruses (HPVs).

test remains an effective, widely used method for early detection of pre-cancer and cervical cancer

may also detect infections and abnormalities in the endocervix and endometrium.

it is recommended that females who have had sex seek regular Pap smear testing.

from annually to every five years. If results are abnormal, and

depending on the nature of the abnormality, the test may need to be repeated in three to twelve months

PROCEDURE

For best results, a Pap test should not occur when a woman is menstruating.

Pap smears can be performed during a woman's menstrual period, especially if the physician is using a liquid-based test; if bleeding is extremely heavy, endometrial cells can obscure cervical cells,

The best time:10 – 20 days after first day of menstrual cycle.

2 days before the test: avoid intercourse,douching, spermicidal foams, creams, jellies, vaginal meds –hide away abnormal cells

inserts a speculum into the patient's vagina, to allow access to the cervix.

Samples are collected from the outer opening or os of the cervix using an Aylesbury spatula and an endocervical brush, or (more frequently with the advent of liquid-based cytology) a plastic-fronded broom.

] The cells are placed on a glass slide and checked for abnormalities in the laboratory.

The sample is stained using the Papanicolaou technique, in which tinctorial dyes and acids are selectively retained by cells.

Unstained cells cannot be visualized with light microscopy. The stains chosen by Papanicolaou were selected to highlight cytoplasmic keratinization,

INTERPRETATION

MAJOR CATEGORIES FOR ABNORMAL PAP SMEAR TEST:

1. ASC-US- atypical squamous cells of undetermined significance- mild abnormality, the squamous cells do not appear completely normal

2. ASC-H ( atypical squamous cells cannot exclude a high grade squamous epithelial lesion)

Cells do not appear normalAt higher risk of being pre

cancerous

3. AGC- atypical glandular cells- Glandular mucus producing cells

found in the endo cervical canal or in the lining of the uterus appear abnormal

4. AIS-endocervical adenocarcinomain situ-- precancerous cells found in the glandular tissue

LSIL-low grade squamous intraepithelial lesion- early changes in the size or shape of cells. (lesion) an area of abnormal tissue.

Considered mild abnormalities caused by HPV infection

HSIL- High grade squamous intra epithelial lesion: there is marked changes in the size and shape of the abnormal precancerous cells.

Are more severe abnormalities and likely to progress to cancer.