2. Clinical Year Review
:Critical Care
By
Gamal Rabie Agmy , MD , FCCP
Professor of Chest Diseases ,Assiut University

3. Early tracheostomy versus Late Tracheostomy
◙ A 2005 meta-analysis of 5 studies (n=406) concluded
that early tracheostomy reduced need for mechanical
ventilation and ICU days.
◙ The Timing of Tracheotomy in Critically Ill Patients
Undergoing Mechanical Ventilation:A Systematic
Review and Meta-analysis of Randomized Controlled
Trials
Chest December 2011, Vol 140, No. 6
The timing of the tracheotomy did not significantly
alter important clinical outcomes in critically ill
patients

4. Novel Modes of Mechanical Ventilation
Mashael Al-Hegelan, Neil R. MacIntyre
Semin Respir Crit Care Med. 2013; 34(4):499-507.

5. Novel Strategies Addressing the Challenge
of Balancing Gas Exchange versus VILI
Airway Pressure Release Ventilation
Airway pressure release ventilation (APRV, also known as BiLevel (Covidien, Boulder, CO) and Bi-phasic (CareFusion,
Yorba Linda, CA), among other trade names) is a time-cycled,
pressure-targeted form of ventilatory support. APRV is
actually a variation of pressure-targeted SIMV that allows
spontaneous breathing (with or without pressure support) to
occur during both the inflation and the deflation phases. APRV
uses a prolonged inspiratory time producing so-called inverse
ratio ventilation (IRV with I:E ratios of up to 4 or 5:1).
Spontaneous breaths thus now occur during this prolonged
inflation period.

6. Novel Strategies Addressing the Challenge
of Balancing Gas Exchange versus VILI
High-frequency Oscillatory Ventilation
High-frequency oscillatory ventilation (HFOV) uses very high
breathing frequencies (120 to 900 breaths per minute [bpm] in
the adult) coupled with very small tidal volumes (usually less
than anatomical dead space and often less than 1 mL/kg at
the alveolar level) to provide gas exchange in the lungs.
The putative advantages to HFOV are twofold. First, the very
small alveolar tidal pressure swings minimize cyclical
overdistension and derecruitment. Second, a high mean
airway pressure can also prevent derecruitment.

7. Novel Strategies Addressing the Challenge
of Balancing Gas Exchange versus VILI
Adaptive Support Ventilation
Adaptive support ventilation (ASV) is an assist-control,
pressure-targeted, time-cycled mode of ventilation that
automatically sets the frequency-tidal volume pattern
according to respiratory system mechanics to minimize the
ventilator work. Conceptually, this minimal ventilator work may
translate into minimal stretching forces on the lungs, which
may, in turn, reduce VILI.
.

8. Novel Modes Addressing Improved
Patient Ventilator Interactions
Volume Feedback Control of Pressure-Targeted
Breaths
As noted previously, pressure-targeted breaths with variable flow features
often synchronize with patient flow demands better than fixed flow, volumetargeted breaths. A drawback to pressure targeting, however, is that a tidal
volume cannot be guaranteed. The most common approach is to use a
measured volume input to manipulate the applied pressure level of
subsequent pressure-targeted breaths.When these breaths are exclusively
supplied with time cycling, the mode is commonly referred to as pressureregulated volume control (PRVC), although there are several proprietary
names (e.g., Autoflow [Draeger, Andover, MA], VC+ [Covidien], Adaptive
Pressure Ventilation [Hamilton Medical Inc., Reno, NV]). When these breaths
are supplied exclusively with patient-triggered, flow-cycling characteristics,
the mode is commonly referred to as volume support (VS). Some ventilators
will switch between these two breath types depending on the number of
patient efforts. Both animal and human studies have shown that these
feedback algorithms function as designed

9. Novel Modes Addressing Improved
Patient Ventilator Interactions
Enhancements on Volume Feedback Control of
Pressure-targeted Breaths
Airway occlusion pressure (P0.1), oxygen saturation (SpO2) and end-tidal
CO2concentration have been incorporated into PRVC and VS mode-control
algorithms to adjust either the target VT or the breath-delivery pattern.
The one system that is commercially available uses end tidal CO 2 and
respiratory rate along with the tidal volume to adjust the applied inspiratory
pressure.[76] Known by the proprietary trade name SmartCare

10. Novel Modes Addressing Improved
Patient Ventilator Interactions
Proportional Assist Ventilation
Proportional assist ventilation (PAV) is a novel
approach to assisted ventilation that uses a clinicianset "gain" on patient-generated flow and volume.PAV
uses intermittent controlled "test breaths" to calculate
resistance and compliance.

11. Novel Modes Addressing Improved
Patient Ventilator Interactions
Neurally Adjusted Ventilatory Assistance
Neurally adjusted ventilatory assistance (NAVA) utilizes a
diaphragmatic electromyographic (EMG) signal to trigger and
govern the flow and cycle of ventilatory assistan] The EMG
sensor is an array of electrodes mounted on an esophageal
catheter that is positioned in the esophagus at the level of the
diaphragm. Ventilator breath triggering is thus virtually
simultaneous with the onset of phrenic nerve excitation of the
inspiratory muscles, and breath cycling is tightly linked to the
cessation of inspiratory muscle contraction. Flow delivery is
driven by the intensity of the EMG signal.

12. Transthoracic Chest
Sonography in Critical Care

13. Ultrasound profiles.
Lichtenstein D A , Mezière G A Chest 2008;134:117-125

15. Tissue pattern representative of Alveolar
Consolidation
Presence of hyperechoic punctiform
representative images
of air bronchograms
Pleural
effusion
Lower lobe

17. Updates in ARDS
Berlin definition:
―Acute lung injury‖ no longer exists. Under the Berlin
definition, patients with PaO2/FiO2 200-300 would now have
―mild ARDS.‖
Onset of ARDS (diagnosis) must be acute, as defined as
within 7 days of some defined event, which may be sepsis,
pneumonia, or simply a patient’s recognition of worsening
respiratory symptoms. (Most cases of ARDS occur within 72
hours of recognition of the presumed trigger.)
Bilateral opacities consistent with pulmonary edema
must be present but may be detected on CT or chest Xray.
There is no need to exclude heart failure in the new ARDS
definition

18. Updates in ARDS
The new criterion is that respiratory failure simply be
―not fully explained by cardiac failure or fluid overload
An
―objective
assessment―–
meaning
an
echocardiogram in most cases — should be performed
if there is no clear risk factor present like trauma or
sepsis

19. ARDS Severity
PaO2/FiO2*
Mortality**
Mild
200 – 300
27%
Moderate
100 – 200
32%
Severe
< 100
45%
*on PEEP 5+; **observed in cohort

20. Mechanical Ventilation in ARDS: 2012 Review
The protocol from the ARMA trial can serve as a guide to
performing low tidal volume ventilation for mechanically
ventilated patients with ARDS:
Start in any ventilator mode with initial tidal volumes of 8
mL/kg predicted body weight in kg, calculated by: [2.3
*(height in inches - 60) + 45.5 for women or + 50 for men].
Set the respiratory rate up to 35 breaths/min to deliver
the expected minute ventilation requirement (generally, 7-9 L
/min)
Set positive end-expiratory pressure (PEEP) to at least 5 cm
H2O (but much higher is probably better), and FiO2 to
maintain an arterial oxygen saturation (SaO2) of 88-95%
(paO2 55-80 mm Hg). Titrate FiO2 to below 70% when
feasible (though ARDSNet does not specify this).
Over a period of less than 4 hours, reduce tidal volumes to
7 mL/kg, and then to 6 mL/kg.

21. Mechanical Ventilation in ARDS: 2012 Review
Ventilator
adjustments
are
then
made with the primary goal of keeping plateau
pressure (measured during an inspiratory hold of 0.5
sec) less than 30 cm H2O, and preferably as low as
possible, while keeping blood gas parameters
―compatible with life.‖ High plateau pressures vastly
elevate the risk for harmful alveolar distension (a.k.a.
ventilator-associated lung injury, volutrauma).

22. Mechanical Ventilation in ARDS: 2012 Review
If plateau pressures remain elevated after following the
above protocol, further strategies should be tried:
Further reduce tidal volume, to as low as 4 mL/kg by 1
mL/kg stepwise increments.
Sedate the patient (heavily, if necessary) to minimize
ventilator-patient dyssynchrony.
Consider other mechanisms for the increased plateau
pressure besides the stiff, noncompliant lungs of ARDS.

23. Mechanical Ventilation in ARDS: 2012 Review
Permissive hypercapnia
Permissive hypoxaemia

24. Limitations in Use of Plateau Pressure for
ARDS
Obesity — may have higher plateau pressures
at baseline and during ARDS than non-obese
patients.
Esophageal manometry is considered superior
to plateau pressures through its measurement
of transpulmonary pressure, considered a
more precise measure of potentially injurious
pressures in the lung. Because it is invasive and
the probes are prone to migration, esophageal
manometry is not widely used.

25. High vs. Low PEEP in ARDS
A strategy employing higher PEEP along with low tidal
volume ventilation should be considered for patients
receiving mechanical ventilation for ARDS. This
suggestion is based on a 2010 meta-analysis of 3
randomized trials (n=2,229) testing higher vs. lower PEEP
in patients with acute lung injury or ARDS, in which ARDS
patients receiving higher PEEP had a strong trend toward
improved survival.
However, patients with milder acute lung injury
(paO2/FiO2 ratio > 200) receiving higher PEEP had a
strong trend toward harm in that same meta-analysis.
Higher PEEP can conceivably cause ventilator-induced
lung injury by increasing plateau pressures, or cause
pneumothorax or decreased cardiac output.

26. Predicting Survival and Outcomes After ARDS
A ―high risk‖ patient profile with a 52% mortality was
identified of severe ARDS (PaO2/FiO2 ratio <
100) with either a high corrected expired volume >=
13 L/min, or a low static compliance < 20 mL/cm
H2O.
Reviews of ARDS outcomes suggest that most
people who survive ARDS recover pulmonary function,
but may remain impaired for months or years in other
domains, both physically and psychologically.

27. Alternative / Rescue Ventilator Modes &
ECMO in ARDS
Some patients with severe ARDS develop severe
hypoxemia or hypercarbia with acidemia despite optimal
treatment with low-tidal volume mechanical ventilation. In
these situations, alternative, salvage or ―rescue‖
ventilator strategies are often employed. Their common
goal is to maintain high airway pressures to maximize
alveolar recruitment and oxygenation, while minimizing
alveolar stretch or shear stress. The most commonly
used alternative ventilatory strategies are high-frequency
oscillatory ventilation (HFOV) or airway pressure release
ventilation (APRV or ―bilevel‖).

28. Surviving Sepsis Campaign: International
Guidelines for Management of Severe
Sepsis and Septic Shock: 2013
Critical Care Medicine, February 2013 • Volume 41 • Number 2
(http://links.lww.com/CCM/A615)

29. 1-early quantitative resuscitation of the septic
patient during the first 6 hrs after recognition (1C);
2-blood cultures before antibiotic therapy (1C);
imaging studies performed promptly to confirm a
potential source of infection (UG);
3-administration of broad-spectrum antimicrobials
therapy within 1 hr of recognition of septic shock
(1B) and severe sepsis without septic shock (1C)
as the goal of therapy;

30. 4-reassessment of antimicrobial therapy daily
for de-escalation, when appropriate (1B);
5-infection source control with attention to the
balance of risks and benefits of the chosen
method within 12 hrs of diagnosis (1C);
6-initial fluid resuscitation with crystalloid (1B)
and consideration of the addition of albumin in
patients who continue to require substantial
amounts of crystalloid to maintain adequate
mean arterial pressure (2C) and the avoidance
of hetastarch formulations (1C)

31. 7-initial fluid challenge in patients with sepsis-induced
tissue hypoperfusion and suspicion of hypovolemia to
achieve a minimum of 30 mL/kg of crystalloids (more rapid
administration and greater amounts of fluid may be
needed in some patients) (1C);
8- norepinephrine as the first-choice vasopressor to
maintain mean arterial pressure ≥ 65 mm Hg (1B);
epinephrine when an additional agent is needed to
maintain adequate blood pressure (2B); vasopressin (0.03
U/min) can be added to norepinephrine to either raise
mean arterial pressure to target or to decrease
norepinephrine dose but should not be used as the initial
vasopressor (UG);

32. 10- dopamine is not recommended except in highly
selected circumstances (2C); dobutamine infusion
administered or added to vasopressor in the presence
of a) myocardial dysfunction as suggested by elevated
cardiac filling pressures and low cardiac output or b)
ongoing signs of hypoperfusion despite achieving
adequate intravascular volume and adequate mean
arterial pressure (1C);
11-avoiding use of intravenous hydrocortisone in adult
septic shock patients if adequate fluid resuscitation and
vasopressor therapy are able to restore hemodynamic
stability (2C);

33. 12-avoiding use of intravenous hydrocortisone in adult
septic shock patients if adequate fluid resuscitation and
vasopressor therapy are able to restore hemodynamic
stability (2C);
13-low tidal volume (1A) and limitation of inspiratory
plateau pressure (1B) for acute respiratory distress
syndrome (ARDS); application of at least a minimal amount
of positive end-expiratory pressure (PEEP) in ARDS (1B);
higher rather than lower level of PEEP for patients with
sepsis-induced moderate or severe ARDS (2C); recruitment
maneuvers in sepsis patients with severe refractory
hypoxemia due to ARDS (2C)

34. 14-prone positioning in sepsis-induced ARDS patients with
a Pao2/Fio2 ratio of ≤ 100 mm Hg in facilities that have
experience with such practices (2C); head-of-bed elevation
in mechanically ventilated patients
15-avoidance of neuromuscular blockers if possible in the
septic patient without ARDS (1C); a short course of
neuromuscular blocker (no longer than 48 hrs) for patients
with early ARDS and a Pao2/Fio2 < 150 mm Hg (2C);
16-a protocolized approach to blood glucose management
commencing insulin dosing when two consecutive blood
glucose levels are > 180 mg/dL, targeting an upper blood
glucose ≤ 180 mg/dL

35. 17-prophylaxis for deep vein thrombosis (1B); use of
stress
ulcer
prophylaxis
to
prevent
upper
gastrointestinal bleeding in patients with bleeding risk
factors (1B);
18-oral or enteral (if necessary) feedings, as tolerated,
rather than either complete fasting or provision of only
intravenous glucose within the first 48 hrs after a
diagnosis of severe sepsis/ septic shock (2C);