Proposal:
I propose to create Markov chains of ARDS patients in our hospital
To calculate transition state probabilities mapping movement of mild, moderate, severe, death, and transfer to floors.
There is not much Markov chain and ARDS, from a brief search only 2 papers.
Of the two they don’t really use data but simulations.
Calculate transition states and also steady states, to characterize each position of ARDS as closed, transient, or recurrent.
I propose after creating a Markov chain and seeing the steady states, look at the utility of each intervention that is “guideline based” which include ventilator (ltvv,high peep, proning, neuromuscular blockers, high frequency oscillatory ventilation, prolonged recruitment maneuver), and nonventilator (fluid restriction, diuresis, Dexamethasone, ecmo)
At each of the different stages (mild, moderate, severe)
After that I hope to describe the effectiveness of these interventions in our South Nassau.
Same thing with pictures
I propose to create Markov chains of ARDS patients in our hospital
To calculate transition state probabilities mapping movement of mild, moderate, severe, death, and transfer to floors.
There is not much Markov chain and ARDS, from a brief search only 2 papers.
Of the two they don’t really use data but simulations.
Markov papers dealing with Acute Respiratory Distress Syndrome
[1, 2]
Salvage use of tissue plasminogen activator (tPA) in the setting of acute respiratory distress syndrome (ARDS) due to COVID-19 in the USA: a Markov decision analysis
In Covid 19 patients given tPA may benefit those critically ill.
What extent tPA may impact population based surviva?
Markov state transition to simulate life critically ill COVID-19 patients as transitioning to recovery / death
1) tPA immediately
2) standard therapy for ARDS
P/F < 60mmHg
47.6% tTPA vs 71% no tPA
Salvage use of tPA may improve recovery of ARDS reducing COVID-19 related mortality
Inclusion criteria P/F < 60 of those eligible for therapeutics
Transition through severe / moderate / mild ARDS, recovery / death
P = 1- exp ^-rt
Standard rate = ln(1-P)/t
Seven day transition probability = 1- exp |7xln(1-P)/t|
A sensitivity analysis of initial (within 7 days) ARDS status (mild vs. moderate vs. salvage use criteria ARDS) was performed (Fig. 3). Utilization of tPA was estimated to significantly reduce 4-week mortality for initial mild (15.2% [tTPA] vs. 60.5% [no tPA]), moderate (26.4% [tTPA] vs. 62.0% [no tPA]), and salvage use criteria (47.6% [tTPA] vs. 71.4% [no tPA]) ARDS.
A Markov computer simulation model of the economics of neuromuscular blockade in patients with acute respiratory distress syndrome
Our computer simulation modeling predicted the mean cost for ARDS patients receiving standard care for 6 months to be $62,238 (5% – 95% percentiles $42,259 – $83,766), with an overall 6-month mortality of 39%. Assuming a ceiling ratio of $35,000, even if a drug (that cost $267 more) hypothetically reduced AQMS from 25% to 21% and decreased intubation time by 6 hours, the net monetary benefit would only equal $137.
1. Choudhury R, Barrett CD, Moore HB, Moore EE, McIntyre RC, Moore PK, et al. Salvage use of tissue plasminogen activator (tPA) in the setting of acute respiratory distress syndrome (ARDS) due to COVID-19 in the USA: a Markov decision analysis. World J Emerg Surg. 2020;15(1):29. Epub 20200420. doi: 10.1186/s13017-020-00305-4. PubMed PMID: 32312290; PubMed Central PMCID: PMCPMC7169373.
2. Macario A, Chow JL, Dexter F. A Markov computer simulation model of the economics of neuromuscular blockade in patients with acute respiratory distress syndrome. BMC Med Inform Decis Mak. 2006;6:15. Epub 20060315. doi: 10.1186/1472-6947-6-15. PubMed PMID: 16539706; PubMed Central PMCID: PMCPMC1431518.
Create transition matrix
Predictors
trial of ards: 2012 berlin: ARDS has no specific diagnostic test. The most recent ARDS diagnostic consensus is summarized in the 2012 Berlin Definition of ARDS (Table 55). Patients with ARDS are at high risk for mortality, which increases with ARDS severity. Importantly, mortality is usually the result of underlying disease, secondary infection, or multiorgan dysfunction rather than refractory respiratory failure.
In 2000, the landmark ARMA trial (also referred to as the ARDSNet trial) showed that a ventilation strategy with tidal volume of 6 mL/kg of ideal body weight and a plateau pressure ≤30 cm water (H2O) resulted in 9% lower mortality than a strategy with 12 mL/kg of ideal body weight and a plateau pressure ≤50 cm H2O (31.0% vs. 39.8%). Although the significance of tidal volume is often emphasized, it is important to remember that the ARMA trial also limited plateau pressure.
In 2000 arm a trial evaluate the benefits of low tidal volume tidal volumes of 4 to 8 mL/kg compared with higher tidal ventilation conventionally used at the time the trial showed a significant 11% reduction in mortality with the use of low tidal volume
This trial also sought to prevent to other causes of ventilator induced lung injury barotrauma or lung injury due to high transpulmonary pressures was prevented in the low tidal volume arm by voiding Plateau pressures of greater than 30 cm H2O current ARDS goals include both at tidal volume 6 mL/kg of predicted body weight and maintenance of the lowest possible plateau pressure
To our med trial affirmed the utility of PEEP as having 3 benefits first it prevents lung injury associated with repeated opening and closing of distal airways and alveoli (elective trauma (second improved homogeneity of the lung parenchyma by reducing gross differences in regional lung compliance third improved VQ mismatch and shunt by maintaining alveolar recruitment
Although PEEP is standard part of lung protective ventilation no definitive level of optimal PEEP has been designated for ventilation of patient with Rx
Despite the clear benefits of 100 tidal volume adherence remains poor
o 2010 Acurasys trial: In 2010, the ACURASYS trial showed that the use of the NMBA cisatracurium within 48 hours of mechanical ventilation in patients with a PaO2:FiO2 <150 reduced 90-day mortality, as compared with placebo (31.6% vs. 40.7%), and increased the number of ventilator-free days.
o Much of the benefit of cisatracurium in the ACURASYS trial is thought to be from minimizing ventilator-induced lung injury from dyssynchrony, once again illustrating the key principle of avoiding harm in the treatment of ARDS. Other benefits include the possible anti-inflammatory effects of NMBA and decreased oxygen requirement by muscle paralysis (see figure below). One negative feature of NMBA use is heavy sedation, which is associated with definite adverse effects.
2013 PROSEVA: The PROSEVA trial showed that, compared with supine positioning, prone positioning within 36 hours of mechanical ventilation in patients with a PaO2:FiO2 ratio <150 mm Hg reduced 28-day (16.0% vs. 32.8%) and 90-day mortality.
Prone positioning requires an experienced care team to move the patient safely and prevent subsequent complications (e.g., pressure ulcers, extubation, intravenous decannulation).
Ventilating patient in prone position may reduce compression of portions of the lung behind the cardiac and mediastinal structures and improve VQ matching and ARDS the PROSEVA trial is a large randomized trial that demonstrated improved mortality in patients with a PF ratio less than 150 who are treated with early prone positioning and low tidal volume early prone positioning for at least 12 hours a day should be considered in patients with severe ARDS
The use of ECMO has been increasing largely due to single prospective randomized control trial performed during the 2009 H1 and 1 influenza pandemic Ceaser trial although this trial suggested improve mortality and ARDS patients referred to a center capable of administering echo ECMO any referred patient's never received ECMO this suggest that improved mortality may have simply been the result of referral to a center that improved with improved expertise and ARDS not due to the treatment of ECMO itself and the patient's with severe refractory hypoxemia both prone positioning and ECMO may be considered however the effectiveness of prone positioning is better supported by data in patients with refractory hypoxemia recruitment maneuver which means applying a high level of CPAP to open collapsed alveoli may be considered
This is supported by the 2017 ATS/ES ICM/CCM guidelines on mechanical ventilation in adults with acute respiratory distress syndrome
o In 2019, the ROSE trial challenged the mortality benefit of neuromuscular blockade reported in the ACURASYS trial. The ROSE trial found no significant difference in 90-day mortality between cisatracurium with deep sedation and light sedation with no neuromuscular blockade. The results of this trial have been controversial given the limited inclusion criteria (of 1004 patients screened, only 340 were included) and other confounders (e.g., differences in sedation).
o The difference in mortality between the two trials is attributed to differences in sedation levels. One explanation offered in an editorial is “reverse triggering” — a phenomenon that describes additional gas delivery and overinflation in deeply sedated, but not paralyzed, patients after a mechanically assisted breath (breath delivered by the ventilator triggers a contraction of the diaphragm, which initiates a spontaneous breath). In the ACURASYS trial, the negative physiological consequences of reverse triggering might have disadvantaged the “control” patients and led to the observed mortality benefit in the paralyzed patients.
o In the ROSE trial, patients in the cisastracurium group also had serious cardiovascular events, providing another reason to avoid this treatment.
2006 The FACTT trial showed that a conservative fluid strategy decreased duration of mechanical ventilation, compared with a liberal strategy. Ventilator management as FACCT trial suggested excessive fluid resuscitation is harmful to ARDS patient's this trial compared conservative to liberal fluid strategies based on central venous pressure and pulmonary artery occlusion pressure which is a surrogate for left atrial pressure although mortality do not differ between groups patients were treated with conservative fluid management showed improved oxygenation and decrease time on the ventilator and in the ICU in patients who are hemodynamically stable and do not have and organ for hypoperfusion minimizing fluid administration is warranted
• glucocorticoid administration
o In 2020, the DEXA-ARDS trial demonstrated a 60-day mortality benefit in mechanically ventilated patients receiving dexamethasone (20 mg intravenously [IV] for 5 days followed by 10 mg for another 5 days) versus controls (21% vs. 36%). Patients receiving dexamethasone also had more ventilator-free days.
I propose after creating a Markov chain and seeing the steady states, look at the utility of each intervention that is “guideline based” which include ventilator (ltvv,high peep, proning, neuromuscular blockers, high frequency oscillatory ventilation, prolonged recruitment maneuver), and nonventilator (fluid restriction, diuresis, Dexamethasone, ecmo)
At each of the different stages (mild, moderate, severe)
After that I hope to describe the effectiveness of these interventions in our South Nassau.
Essentially it is a review paper going through all the trials in ARDS and seeing if they are effective in our hospital.
Comments
Post a Comment