Respiratory pathophysiology 6 Flashcards
A patient with pulmonary hypertension develops tricuspid regurgitation. Which treatments will MOST likely improve this patient’s condition? select 3
a. hypothermia
b. nitric oxide
c. nitroglycerine
d. nitrous oxide
e. PEEP
f. hyperventilation
b. nitric oxide
c. nitroglycerine
f. hyperventilation
Pulmonary artery hypertension is defined as a
mean PAP >25 mmHg
______________________ increases as a function of increased vascular smooth muscle tone, vascular cell proliferation, and/or pulmonary thrombi
Pulmonary vascular resistance
With pulmonary hypertension avoid conditions that
increase PVR
Conditions that increase PVR include
hypoxemia
hypercarbia
acidosis
hypothermia
Pulmonary hypertension increases ___________ workload, and this can progress to
right ventricular workload; RV failure (cor pulmonale)
With pulmonary hypertension should preoperative medications that reduce PVR be held?
no
Patients with pulmonary hypertension can be sensitive to ______________ as cardiac output is relatively fixed
inadequate preload
_________ should be treated aggressively in pulmonary hypertension
hypotension
___________ is better tolerated than ______________ anesthesia in pulmonary hypertension
Epidural anesthesia is better than spinal
Ventilation strategies for pulmonary hypertension include
inhaled nitric oxide
high-frequency jet ventilation
Another consequence of decreased RV stroke volume in pHTN is an increased RV volume at the end of diastole. This leads to
tricuspid regurgitation
Causes of pulmonary hypertension include
COPD
hypoxemia & hypercarbia
left heart dysfunction
mitral valve disease
congenital heart disease
connective tissue disorders
chronic thromboembolism
portal hypertension
Normal pulmonary vascular resistance is
150-250 dynes/sec/cm
Things that lead to increased PVR:
hypoxemia
hypercarbia
acidosis
SNS stimulation
Pain
Hypothermia
Drugs that lead to increased PVR:
nitrous oxide
ketamine
desflurane
Ventilatory effects that lead to increased PVR:
increased intrathoracic pressure
mechanical ventilation
PEEP
atelectasis
Things that lead to decreased PVR:
increased PaO2
hypocarbia
alkalosis
Drugs that lead to decreased PVR:
inhaled nitric oxide
nitroglycerin
phosphodiesterase inhibitors (sildenafil)
prostaglandins PGE1 & PGI1
calcium channel blockers
ACE inhibitors
Ventilation effects that lead to decreased PVR:
decreased intrathoracic pressure
spontaneous ventilation
preventing coughing/straining
Elevated RA pressure can open the
foramen ovale, leading to a right to left intracardiac shunt
If the pHTN patient experiences decreased SVR give
vasopressors
If the pHTN patient experiences loss of atrial kick, give
NSR
If the pHTN patient experiences increased PVR or RV failure, give
inhaled nitric oxide or iloprost
What is the equation for PVR?
PVR= (mean PAP-PAOP) x 80/ CO
Carbon monoxide:
a. shifts the oxyhemoglobin dissociation curve to the right
b. production is highest with isoflurane
c. binds to the oxygen binding site on hemoglobin with an affinity 200 times that of of oxygen
d. poisoning is reversed with methylene blue
c. binds to the oxygen binding site on hemoglobin with an affinity 200 x that of oxygen
Carbon monoxide displaces __________________ which reduces
O2 from hemoglobin which reduces CaO2
Carbon monoxide shifts the oxyhemoglobin dissociation curve
to the left, further starving tissues of oxygen
Patients at risk for carboxyhemoglobinemia include
burn victims, smokers, and patients exposed to desiccated soda lime
A ________ does not measure CoHgb and may give a falsely _________ result
pulse oximeter; elevated
A __________________ is required to diagnose carboxyhemoglobinemia
co-oximeter
The treatment for carboxyhemoglobinemia is
oxygen administration; hyperbaric oxygen therapy may be required
When soda lime is desiccated, the risk of carbon monoxide formation is greatest with
desflurane (desflurane>isoflurane»» sevoflurane)
Carbon monoxide poisoning leads to
metabolic acidosis
Patients with carbon monoxide poisoning appearance:
cherry red appearance
(don’t become cyanotic)
Hyperbaric oxygen is indicated if CoHgb exceeds what percent of total hemoglobin?
25%
100% O2 should be administered until the CoHgb is less than:
5%
Identify the strongest indications for intubation and mechanical ventilation. (select 2):
a. PaCO2 >60 mmHg
b. Vital capacity 25 mL/kg
c. inspiratory force <25 cm H2O
d. respiratory rate 35 breaths per minute
a. PaCO2 >60 mmHg
c. Inspiratory force <25 cmH2O
Benefits of tracheal intubation include:
a patent airway
controlled ventilation
ventilation with high airway pressure
secured airway (protection from gastric aspiration)
removal of secretions
lung isolation
medication administration
Strong indications for mechanical ventilation include:
vital capacity <15 mL/kg
inspiratory force <25 cm/H2O
PaOP <200 mmHg (on 100% FiO2)
A-a gradient >450 mmHg (on 100% FiO2
PaCO2 >60 mmHg
RR >40 or < 6 bpm
What drugs can be administered down the ETT?
NAVEL
narcan, atropine, vasopressin, epinephrine, lidocaine
Subjective signs of respiratory distress include
dyspnea
accessory muscle use
anxiety and restlessness
SNS stimulation (pupil dilation, diaphoresis)
mouth breathing during inspiratory efforts
lip cyanosis
pursed lip breathing or self-PEEP
Identify the absolute indications for one-lung ventilation. (select 2)
a. esophageal resection
b. bronchopleural fistula
c. pulmonary infection
d. thoracic aortic aneurysm repair
b. bronchopleural fistula
c. pulmonary infection
