Answer 1
Would recommend discussing "The Look" as an indication for mechanical ventilation rather than focusing on any given value of respiratory rate, pCO2, pO2, etc.
Answer 2
a. BiPAP decreases the work of breathing which is often excessive due to the presence of auto-PEEP.
b. In pooled data, the risk of intubation may be reduced from as high as 75% to as low as 25%. This represents a NNT = 2.
c. Sleep Apnea; Pulmonary Edema secondary to CHF; Neutropenic Patients with Pulmonary Infiltrates
The use of CPAP/BiPAP in post-extubation respiratory failure has been studied and, while controversial, has not been shown to be beneficial and, in fact, may increase mortality. This reinforces the concept if a patient needs to be intubated NOW, any delay in doing so might be detrimental.
Answer 3
Clearly, many satisfactory options and therefore would use this opportunity to discuss the relative advantages/disadvantages of various modes and ventilator strategies. For a COPD patient, a generally accepted strategy would include a/c mode with modest TV and Rates, PEEP adjusted to approximately 70% of the estimated intrinsic-PEEP (to minimize the work of triggering the ventilator), a modest FiO2
(since VQ mismatch should be easily correctable), and an I:E ratio of 25% or less (to minimize the likelihood of developing significant intrinsic-PEEP).
Answer 4
Would emphasize these concepts:
Answer 5
Normalized vital signs, reduced respiratory effort/apparent work of breathing, adequate pulse oximeter saturation, absence of abdominal paradox, etc.
Answer 6
High? - Inadequate sedation with excessive catecholamine output.
Low? - The change from negative pressure ventilation (i.e., spontaneous breathing) to positive pressure ventilation with resultant increased intrathoracic pressures and decreased venous return +/- the effects of peri-intubation sedatives.
Answer 7
Hypercapnic secondary to increased respiratory system load related to increased airway resistance and intrinsic-PEEP.
Answer 8
V/Q Mismatch which is usually easily corrected.
Answer 9
Compliance = TV / (Pplat - PEEP) = 600/(15 - 5) = 60
Answer 10
The high peak to plateau gradient is most consistent with an increased resistance.
Answer 11
Increased intrinsic-PEEP.
Answer 12
Increased intrinsic-PEEP.
Answer 13
Decrease TV, decrease RR, decrease the inspiratory time, continue bronchodilators.
Anwer 14
Compliance = 600 / (30 - 5) = 24
Answer 15
3 or 4 quadrant airspace filling disease on CXR
severe hypoxemia
reduced lung compliance
normal pulmonary capillary wedge pressure
Answer 16
Hypoxemic (in the acute phase although later, in the proliferative phase, hypercapnic failure may result)
Answer 17
Shunt which is typically relatively refractory to supplemental oxygen.
Answer 18
In addition to increasing the FiO2
and titrating PEEP, one should focus on the often overlooked importance of maximizing the MVpO2
through reducing oxygen consumption (i.e., treat the fever and sepsis, reduce work of breathing through optimizing ventilator settings, sedation and paralysis) and augmenting oxygen delivery through transfusion and possible use of pharmacologic agents to increase cardiac output. One might also discuss the use of positional changes to increase pO2.
Answer 19
The same general
treatment strategy would apply. However, greater emphasis would be placed on
pharmacologic management including aggressive diuresis, afterload reduction,
inotropic support, morphine, and nitroglycerin as well as the possible role for
rotating tourniquets. In addition, one should emphasize the importance of
considering revascularization (in the case of acute cardiac ischemia), the use
of an Intra-Aortic Balloon Pump (if associated with cardiogenic shock), and the
generally prompt response of high-pressure pulmonary edema (typically requiring
only a few hours to reverse as compared to the typical several days of
low-pressure pulmonary edema typical of ARDS).
Answer 20
Patients in status asthmaticus are extremely difficult to ventilate; the peak pressures are extremely high and air-trapping results in dangerously high levels of auto-PEEP. Thus, one typically employs extremely small TV’s (to minimize the risk of barotrauma associated with auto-PEEP) and short inspiratory times (which will reduce the amount of auto-PEEP even though the peak pressures will be elevated). In addition, this is a typical scenario in which one employs a strategy of permissive hypercapnea; i.e., accept an elevated PaCO2 as long as the pH remains above an arbitrary level (usually around 7.20).
Answer 21
Many possibilities
including barotrauma, nosocomial ventilatory associated pneumonia, GI bleeding,
MSOF, etc.
Answer 22
The differential should include mechanical tube problems and pneumothorax. The
immediate response should include checking the peak and plateau pressures,
passing a suction catheter through the ET tube, examining for evidence of
asymmetric/absent breath sounds, and review of a CXR.