Cairo: Pilbeam's Mechanical Ventilation, 6th Edition

Chapter 08: Initial Patient Assessment

WorkBook Answer Key

Key Terms Crossword Puzzle

Chapter Review Questions
1.	Patient’s color, respiratory rate, breathing pattern, accessory muscle use, chest movement, breath sounds, work of breathing, and level of consciousness.
2.	Ventilator flow sheet.
3.	An operational verification procedure.
4.	(any of the following) Before an ABG sample is drawn; when a physician has entered new orders; prior to obtaining hemodynamic or pulmonary function data; when a change in ventilator settings has been made; when an acute change occurs in the patient’s condition; when ventilator performance is questionable; or when a patient returns from a testing procedure.
5.	(a) In cases where continuous FIO2 measurements are not available on a particular ventilator, intermittent measurements of FIO2 are usually sufficient for adult patients and (b) continuously for an infant.
6.	Chest auscultation to confirm adequate volume delivery and proper ET tube placement
7.	15 minutes
8.	1 to 2 cm H2O
9.	2-3 L/min
10.	(a) PEEPI raises the baseline, and because this is not set on the ventilator, there is no automatic adjustment for the raised baseline. Therefore, the patient must increase the work of breathing when attempting to trigger a breath. This results in use of accessory muscles of inspiration and labored breathing. (b) Adding PEEPE makes triggering the ventilator easier.
11.	If auto-PEEP is present, a number of strategies can be used to reduce its effects, including increasing the flow (reducing the inspiratory time [TI]), reducing VT, or reducing the rate (i.e., reducing =), suctioning the patient, or changing modes to allow for more spontaneous breaths. It is important to recognize that it may not always be possible to eliminate auto-PEEP, particularly in patients with increased flow resistance and airway closure. The addition of extrinsic PEEP (PEEPE) in these cases may make triggering easier.
12.	An HME can add mechanical dead space, thus decreasing VA.
13.	VA = VT  VDAN  VDmech. 775 mL  160 mL  85 mL = 530 mL.
14.	(a) Anatomic dead space and (b) mechanical dead space
15.	Decrease; increase
16.	An inspiratory pause or hold
17.	When a patient is making active respiratory efforts, has a high frequency, or is resisting inspiratory time extension, plateau pressure is difficult to obtain.
18.	30 cm H2O
19.	Peak inspiratory pressure and PEEP
20.	Plateau pressure and PEEP
21.	The difference between the PIP and Pplateau readings (PIP − Pplateau) is the transairway pressure (Pta).
22.	An increase in airway resistance
23.	The patient requires suctioning or is biting on the tube; the tube is kinked; bronchospasm is occurring; or the HME is plugged with moisture or secretions.
24.	The mean airway pressure parallels the mean alveolar pressure and is therefore useful in examining the benefits and side effects of positive-pressure ventilation. It influences tissue oxygenation and affects lung volumes and cardiac output.
25.	Expiratory pause
26.	10 cm H2O; terminate inspiration
27.	Patient coughing; an increase in airway resistance (bronchospasm or the patient requires suctioning); a decrease in compliance (pulmonary edema, pneumonia, and pleural effusion); and the patient biting down on the tube.
28.	5-10 cm H2O; a leak in the patient-ventilator circuit.
29.	Patient disconnection from the ventilator; leaks around an underinflated ET tube cuff; leaks around the humidifier, through the water feed lines to the humidifier, and at water traps; loose tubing connections; closed suction catheters; in-line thermometers; at end-tidal carbon dioxide monitors.
30.	The patient should be manually ventilated.
31.	A leak can be identified in a number of ways. The simplest way is to note whether the peak pressure and the exhaled volume are lower than previous measurements. The volume-time waveform can also be checked; if it resembles an igloo, the inspired VT is greater than the expired VT.
32.	(1) Listen over the trachea to establish that the cuff is maintaining an adequate seal; (2) remove the patient from the ventilator and have another clinician manually ventilate the patient with a resuscitation bag; (3) check for leaks in the ventilator circuit; (4) occlude the Y-connector and cycle the ventilator; if the high pressure is not reached, a significant leak is present; (5) pinch shut the main inspiratory tubing on the distal side of the humidifier; if the PIP alarm sounds, there is no leak in the humidifier system between your hand and the ventilator; if the alarm does not sound, the leak is either in the humidifier assembly or where the circuit attaches to the ventilator or humidifier; (6) pinch shut the large-bore expiratory line and manually cycle the ventilator; if the PIP limit alarm fails to activate, the leak is near the Y-connector; (7) check all tubing connections and water traps.
33.	The ventilator would stay in inspiration and prevent flow cycling.
34.	(a) MOT—The cuff is inflated during positive-pressure ventilation until no leak is heard at end-inspiration. The leak is detected by listening with a stethoscope over the suprasternal notch or lateral neck. With the MOT, just enough measured volume is injected into the cuff to stop all leakage around the cuff, resulting in the lowest cuff pressure needed to create a seal. The required volume is then recorded.
(b) MLT—The cuff is inflated during positive-pressure ventilation until a leak is no longer heard on inspiration. A small amount of air is removed from the cuff so that the leak can just be heard at end-inspiration. Some clinicians prefer MOT because of concerns about aspiration with MLT.
35.	Infection, tissue necrosis, late-stage carcinoma, Hodgkin’s disease, leukemia, and hypothyroidism or other metabolic abnormalities.
36.	Right arterial pressure and right ventricular end diastolic pressure.
37.	CVP measurement should be taken at the end of expiration when intrapleural pressure returns to normal or is at its lowest value during the respiratory cycle.
38.	Critically ill patient who has severe cardiopulmonary complications and/or problems with fluid management.
39.	Once per shift or following any change in patient condition
40.	Observing and recording a patient’s vital signs (i.e., systemic arterial blood pressure [BP], heart rate [HR], temperature [T], f, oxygen saturation measured by pulse oximetry [SpO2], and physical appearance) can help staff members evaluate possible changes in the patient’s overall condition. In mechanically ventilated patients, f, HR, and SpO2 are monitored continuously. Temperature and arterial BP may also be monitored continuously, but more often they are measured intermittently. Inspection, palpation, percussion, and auscultation of the chest should also be performed.
41.	Abdominal distention causes upward pressure on the diaphragm, which causes a restrictive-type problem, making it difficult to ventilate the patient.
42.	20-25 mm Hg or 27-34 cm H2O.
43.	The trachea in a hypotensive patient could be damaged, because the cuff pressure can exceed the perfusion pressure to the trachea.
44.	(a) Use minimum leak technique (MLT); (b) establish MLT in which only 50-100 mL of VT is lost; (c) the cuff should require no more than 5 mL for inflation; (d) if a minimal leak cannot be maintained with a cuff volume less than 5 mL, ensure that the cuff pressure is less than 25 cm H2O; (e) if steps 1 through 4 cannot be achieved, the patient should be followed for tracheal stenosis for at least 1 year after discharge.
45.	(a) The cuff and artificial airway have moved up in the patient’s airway and are in the larynx or pharynx and (b) the endotracheal tube may be too small for the patient, requiring a large volume to maintain a seal.
46.	By positioning a three-way stopcock between a blunt-tipped needle inserted into the cut pilot balloon and a syringe, the cuff can be inflated and kept inflated.
47.	To prevent pressure injuries to the gums, mouth, or lips from the constant pressure of the tube.
48.	70-100 mL/cm H2O
49.	CS = VT ÷ (Pplateau  EEP)
50.	Air trapping, pulmonary edema, atelectasis, consolidation, pneumonia, pneumothorax, hemothorax, pleural effusion, flail chest, changes in chest wall muscle tension, pneumomediastinum, and abdominal distention.
51.	The VT will decrease.
52.	CD = VT ÷ (PIP  EEP)
53.	Decreases; increases
54.	PIP would increase, but the delivered VT would not change.
55.	740 mL ÷ 44 cm H2O  8 cm H2O = 740 ÷ 36 = 0.02 L/cm H2O
56.	58 cm H2O  51 cm H2O ÷ 0.5 L/sec = 7 cm H2O ÷ 0.5 L/sec = 14 cm H2O/L/sec
57.	There is a leak in the ventilator circuit.
58.	The Pplateau is 35 cm H2O.
59.	450 mL ÷ 35 cm H2O  5 cm H2O = 15 mL/cm H2O
Critical Thinking Questions
1.	One problem could be that the sensitivity is set too high. The patient cannot generate the negative inspiratory effort necessary to trigger the ventilator. The sensitivity needs to be adjusted to a level at which the patient can trigger a breath with minimal effort. If the sensitivity is set correctly, PEEPI is present. The patient is unable to “draw through” the positive pressure in the airway, unable to trigger a breath. If adjustments to increase the expiratory time (e.g., decrease frequency or VT, increasing the inspiratory flow rate) do not alleviate the problem, the addition of PEEPE may help.
2.	The endotracheal tube is too small for a person of this size. The cuff pressure of 40 cm H2O needed to maintain a seal will cause tracheal damage. The patient needs to be extubated and a larger tube inserted. To avoid problems with reintubation, a tube changer could be used.
3.	When a set inspiratory pressure is delivered to the airway, tidal volumes depend on lung mechanics. ARDS results in a decrease in CS. In this case, an inspiratory pressure of 30 cm H2O was delivering tidal volumes ranging from 400 to 450 mL. As the disease process resolves, the elastic recoil of the lung improves. The same delivered pressure results in an increased VT.
4.	The transairway pressure is the pressure required to overcome airway resistance; 43 cm H2O  18 cm H2O = 25 cm H2O.
Case Studies
Case Study 1

1.	10 cm H2O above and below the PIP, high-pressure alarm at 52 cm H2O, and low- pressure alarm at 32 cm H2O
2.	100 mL below the set VT, which is 600 mL.
3.	Perform an inspiratory hold maneuver.
4.	The PTA is 4 cm H2O, which leads to the conclusion that airway resistance is minimal. The static compliance is 700 mL ÷ (42  5 cm H2O) = 19.5 mL/cm H2O. A significant restriction to ventilation seems to be present. This could mean that the patient has developed ARDS. However, other information needs to be assessed (e.g., chest X-ray results, arterial blood gas values).

Case Study 2

1.	The patient may be biting on the endotracheal tube, coughing, in need of suctioning, or not in sync with delivered breaths.
2.	When the high-pressure limit is reached, inspiration is terminated prematurely. If the high pressure is activated constantly, the low tidal volume and low minute volume alarm thresholds will be reached, activating both alarms.
3.	The patient may be agitated and confused because of pain; in that case, giving a sedative may be appropriate. Agitation and confusion can also be due to hypoxia; this requires drawing an ABG sample. The patient could have retained secretions and/or bronchospasm. Auscultation of breath sounds is appropriate. Vital signs should be assessed to rule out any other undetected problem.

Case Study 3

1.	0800: PTA = 35  30 = 5 cm H2O; 1000: PTA = 39  34 = 5 cm H2O; 1100: PTA = 45  39 = 6 cm H2O; 1130: PTA = 50  44 = 6 cm H2O.
2.	The PTA is basically unchanged throughout the course of the 3.5 hours. This shows that airway resistance has not changed. However, the Pplateau has increased each time the information was gathered. This information points to a decreasing CS.
3.	The cause of the decreasing CL could be the development of ARDS, pneumothorax, hemothorax, pneumonia, pleural effusion, pneumomediastinum, or abdominal distention.
4.	Assessment should include evaluation of breath sounds and percussion notes, palpation of the chest and abdominal wall, obtaining a chest radiograph, obtaining an arterial blood gas sample, and studying laboratory data.

Case Study 4

1.	0630: PTA = 36  23 = 13 cm H2O; 0835: PTA = 39  22 = 17 cm H2O; 1030: PTA = 41  23 = 18 cm H2O; 1230: PTA = 46  19 = 27 cm H2O.
2.	The PTA rose over the course of the 6 hours, whereas the Pplateau remained unchanged and then improved at 1230. This information indicates increasing airway resistance.
3.	The increased airway resistance could be due to retained mucus, an obstructed airway, or bronchospasm.
4.	Assessing breath sounds in this situation would be most important. The presence of wheezes indicates bronchospasm, and rhonchi indicate retained mucus. The treatment for increased airway resistance needs to be directed at the specific cause of the increase, such as suctioning the airway, administering a bronchodilator treatment, and/or clearing the obstruction.
NBRC-Style Questions
1.	C
2.	C
3.	D
4.	C
5.	A
6.	D
7.	C
8.	D
9.	C
10.	D