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VT should be 5 - 7ml.kg (350 - 450 ml)
PaCO2 should be 6 - 8 kPa
PIP should be less than 30 cm H2O
The main exclusion to hypercapnoeic ventilation is in patients suspected of having sustained brain injury, when PaCO2 should be maintained at between 4.5 kPa and 5.5 kPa).
WHEN USING BIPAP, IT IS VERY EASY FOR TIDAL VOLUME & MINUTE VOLUME TO CHANGE.
RONE POSITION VENTILATION
In general patients will be turned prone for the night and returned to the supine position for the day.
If the patient needs defibrillation/countershock, get on with it using back paddle pushed under the patient. Ask yourself whether the arrest is because the patient was underventilated (tube kinked or fell out)
PROTOCOL FOR DECANNULATION: TRACHEOSTOMY
If the tracheostomy has been performed using the non-surgical percutaneous technique always assume that reinsertion of the tube will be difficult. The tube is placed between tracheal rings which may immediately take up their original anatomical shape (the rings close down like fingers in a tightly closed fist). In these circumstances, if there is doubt:
Make sure that the physio knows you are likely to decannulate.
You are not advised to decannulate in the small hours of the morning!
Do not start nasogastric feeding for at least 2 and preferably 4 hours; the larynx remains incompetent for quite long periods. You can probably guess this because the patient originally tolerated a trache-tube without coughing, and the hoarse voice indicates incomplete closure of the vocal cords, or leakage of air from the stoma.
PROTOCOL FOR TREATMENT OF PERSISTENT HYPOXAEMIA IN ACUTELY ILL PATIENTS
This protocol is aimed to assist management of patients suffering from ALI or ARDS. It assumes that mechanical causes of hypoxaemia have been excluded ie inadvertent endobronchial intubation, lobar collapse due to bronchial obstruction (sputum, foreign body), pneumothorax. It is sensible to exclude obvious problems with a chest X-ray and, if necessary, bronchoscopy. Every effort should be made to maintain PaO2 >9kPa and SpO2 >93%
For the purposes of this protocol, persistent hypoxaemia will be defined as a PaO2 of <8.5kPa, or a SpO2 of <91% for >12 hours when receiving an FIO2 of >0.6 (i.e. a PaO2/FIO2 ratio <14kPa).
Other indications are:
(a) PaO2 of <7.5kPa, or a SpO2 of <88% for >2 hours if breathing 85% oxygen
(b) inability to raise PaO2 above 8kPa
Patients should already be receiving hypercapnoeic ventilation (PaCO2 >7.5 kPa) and low level EEP (5 cm H2O)
TREATMENT REGIMENS ARE:
PROTOCOL FOR BRONCHO-ALVEOLAR LAVAGE IN MECHANICALLY VENTILATED PATIENTS IN CRITICAL CARE
CHOICE OF AREA FOR BRONCHO-ALVEOLAR LAVAGE
Outside the Intensive Therapy Unit, broncho-alveolar lavage is performed on a single lung segment, usually the segment showing consolidation. Unfortunately, in the critically ill patient in the ITU, radiological evidence or clinical signs pointing to a particular area of interest are often lacking, and the segmental area to undergo lavage should be chosen at the time of fibreoptic bronchoscopy. Not uncommonly, however, there is no obvious area, and lavage should be performed in three different segments.
1) Prior to lavage (as for any bronchoscopy) the patient must be ventilated (pre-oxygenated) with 100% oxygen for at least 5 (and preferably 20) minutes.
2) The sealed suction unit etc must be replaced with a bronchoscope swivel adaptor.
3) Immediately prior to bronchoscopy, minute and tidal volume set up on the ventilator should be increased by 25% to accommodate the gas loss due to bronchoscopic suction and leakage around the swivel. In these circumstances, this is sensible practice even when the ventilator is pressure cycled.
4) The patient requires adequate sedation. If an oral tube is present, the patient will require a muscle relaxant, to prevent biting on the endotracheal tube/fibrescope: it is not usually possible to insert a bite guard. Sedation is best achieved with a benzodiazepine (midazolam or diazepam). Propofol may cause significant hypotension. An additional bolus of an opioid may be helpful.
5) The sputum trap may require changing prior to lavage, particularly if lignocaine has been used as a local anaesthetic.
6) Following formal bronchoscopy, three sub-segmental areas are chosen for lavage. The bronchoscope is pushed into the segment until it is stuck and can be pushed no further. This effectively "plugs" and isolates the segment, although large changes in lung volume with ventilator inflation may unplug the fibrescope. Sixty (60) ml of warmed (37oC) saline is injected into the segment. After a 2 second delay, this is aspirated into the suction trap. Aspiration is repeated.
7) The other two areas are now lavaged. It is important that volumes are limited to 180 ml (total), if both lungs are lavaged. Bilateral lavage with high volumes (500 ml) can (and does) cause significant hypoxaemia.
8) If the trap is more than half full, it must be replaced, otherwise the whole sample may be inadvertently suctioned away.
9) At the end of the procedure, minute and tidal volume should be readjusted.
10) Pre-oxygenation should be continued for at least 10 minutes after completion of the procedure.
4.0 HAEMODYNAMICS – CONTENTS
Determinants of Cardiac Output
Mean Arterial Pressure
Arterial Wave Form Analysis
Central Venous Pressure
Non Invasive Haemodynamic Parameters
Vasoactive Drug Therapy
Fluid Replacement - Colloids, Blood Products & Albumin
What is CVVH?
How does CVVH work?
Acute Renal Injury
Guidelines for Doctrecogin Alpha
dult Protocol for Meningococcal Septicaemia
Insufficient cardiac output (heart rate x stroke volume) will over time yield inefficient anaerobic metabolism that cannot be sustained indefinitely. It is for this reason that matching output to demand is a critical factor within critical care and it requires a careful and rationalised titration of specific drugs or fluids.
- HAEMODYNAMIC MANAGEMENT IN CRITICAL CARE
Some patients in critical care can respond very well to straight forward basic management. However, it is not uncommon for some patients to present a significant challenge. There may be a whole host of issues, (often more than one) that present a consequent challenge for ensuring that the patient is optimised. Some examples include:
DETERMINANTS OF CARDIAC OUTPUT
Pre contractile fibre stretch in diastole is known as preload. Starling’s Law dictates that muscle fibre length at end diastole influences the vigour of contraction. Therefore, ejected volume will increase as filling occurs. However, in cardiac failure or excessive delivery of fluid, the ventricle can become preload insensitive and there will be less ejected volume associated with filling. Other issues can result in reduced diastolic compliance (e.g. hypertension, valve dysfunction, high PEEP)
Preload is measured in critical care though the use of CVP monitoring.
CVP reliability should be used with caution in patients where there is evidence of cardiac impairment or suspected problems with afterload and/or contractility
This is the muscular tension that is developed during systole per unit of blood flow. The systolic wall stress is affected by blood pressure, wall thickness and ventricular volume. Moderate changes can usually be met by increases in heart rate, contractility or preload so output remains the same. Once these reserves are met, then afterload can significantly rise. On the other hand, if afterload is too low, then efforts to compensate can result in significant changes to heart rate, contractility and preload until the patient becomes severely compromised
Non invasive cardiac output monitoring allows for observation of systemic vascular resistance which provides a means of measuring the degree of afterload. Systemic Vascular Resistance is measured
Contractility refers to the ability of the myocardium to contract. This can be affected by many stimuli and these can be independent of the preload and afterload status of the patient, (some examples include electrolye abnormalities, acid base balance, ischemia, anoxia, drugs and toxins). Changes in contractility are rare. For example:
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