Chapter 290 - Disorders of Ventilation Flashcards
arterial level of carbon dioxide is maintained between which values at sea level?
37 - 43 mmHg
3 disturbances of PaCO2
altered CO2 production
altered minute ventilation
altered dead space fraction
Acute ventilatory disorders are often due to which disturbance?
Altered CO2 production
Chronic ventilatory disorders are due to
- inappropriate levels of minute ventilation
2. increased dead space fraction
Acts as the initial integration site for many of the afferent nerves relaying information about Pao2, Paco2, pH, and blood pressure from the carotid and aortic chemoreceptors and baroreceptors to the CNS
Dorsal Respiratory Group
Where is the respiratory rhythm generated?
Ventral respiratory group
parafacial respiratory group
important for the generation of active expiration
parafacial respiratory group
Area responsible for the generation of various forms of inspiratory activity, and lesioning of this area leads to the complete cessation of breathing
pre-Bötzinger complex
During normal sleep there is an attenuated response to hypercapnia and hypoxemia resulting in mild nocturnal hypoventilation that corrects upon awakening.
True
Hypoventilation disorders result from reduced minute ventilation or increase in dead space. What are the 4 major categories?
- parenchymal lung and chest wall disease
- sleep disordered breathing
- neuromuscular disease
- respiratory drive disorders
This is frequently a sign of reduced respiratory muscle force generation
New onset orthopnea
Characteristic sequence of the clinical course of patients with chronic hypoventilation from neuromuscular or chest wall disease
- Asymptomatic stage
- Nocturnal hypoventilation
- during REM and later in NREM
- Daytime Hypercapnia
- VC drops
Hallmark of all alveolar hypoventilation syndromes
increase in Alveolar pCO2 and therefore in PaCO2
Elevated plasma bicarbonate in the absence of volume depletion is sug- gestive of hypoventilation
True
Elevated PaCO2 with a normal pH confirms what condition
CHRONIC alveolar hypoventilation
Most frequent sleep disorder leading to chronic hypoventilation accompanied by obstructive sleep apnea
Obesity hypoventilation syndrome
Which Questionnaire has been validated in the primary care setting and identifies OSA
Berlin Questionnaire
Which questionnaire has been validated as a screening tool for OSA in sleep and surgical clinics.
STOP-Bang
treatment of hypoventilation and apneas, both central and obstructive, in patients with neuromuscular and chest wall disorders
Nocturnal non-invasive positive-pressure ventilation (NIPPV)
Criteria for using nocturnal NIPPV if symptoms of hypoventilation exist
- Paco2 ≥45 mmHg
- nocturnal oximetry ≤88% for 5 consecutive min
- maximal inspiratory pressure <60 cmH2O
- FVC <50% predicted
- sniff nasal pressure <40 cmH2O.
Pharmacologic agents that stimulate respiration, such as medroxy- progesterone and acetazolamide, have been poorly studied in chronic hypoventilation and should not replace treatment of the underlying disease process.
true
Diagnostic criteria for OHS
BMI ≥30
chronic daytime alveolar hypoventilation (Paco2 ≥45 mmHg at sea level) in the absence of other known causes of hypercapnia.
Treatment of OHS
Weight reduction
NIPPV
OHS Treatment reserved for patients not able to tolerate high levels of CPAP support or patients that remain hypoxemic despite resolution of obstructive respiratory events
BIPAP
treatment for patients with OHS but with no evidence of OSA
BIPAP
Central hypoventilation syndrome presenting later in life or in the neonatal period
Ondine’s curse
Abnormalities of which gene have been implicated in the pathogenesis of Congenital central hypoventilation syndrome
PHOX2b
anxiety disorders and panic attacks are NOT synonymous with hyperventilation
True
Once chronic hyperventilation is established, a sustained increase by how many percent in alveolar ventilation is enough to perpetuate hypocapnia?
10%
Overall prevalence of OSA in middle aged men
3-4%
Overall prevalence of OS in middle Ged women
2%
Chest wall disease
A- abdominal distention
K - Kyphoscoliosis
O - Obesity
Impaired Neuromuscular transmission
Myasthenia Gravis
ALS
Phrenic nerve injury
Spinal cord lesion
Sleep disordered breathing
Upper airway obstruction
Intermittent hypoxemia
Muscle weakness
Myopathy
Malnutrition
Fatigue
Diminished drive
Sleep disordered breathing Narcotic/ sedative use Brainstem stroke Hypothyroidism Primary alveolar hypoventilation
In how many percent of cases is sleep
Disordered breathing in the form of OSA
90%
In patients with hyperventilation, an initial event leads to increased alveolar ventilation and a drop in PaCO2 to how many mmHg?
20mmHg
ABG findings that can confirm chronic hyperventilation
Compensated Respi Alk
Near normal pH
Low PaCO2
Low HCO3
