Mechanical Ventilation and RAD - Prof. K. Chellum Oration / CMC Vellore 26th June 2004
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Transcript of Mechanical Ventilation and RAD - Prof. K. Chellum Oration / CMC Vellore 26th June 2004
Mechanical ventilation and RAD
Dr Satish Deopujari
Prof. K. Chellum Oration / CMC Vellore
26th June 2004
Incidence of M.V. in RAD in India ?
Do we under ventilate these patients.
Aggressive management ………..
Proper oxygenation warmed and humidified
Continuous nebulization what dose ?
Look for hypokalemia
Steroids / Ipatropium bromide / MgSO4
Hydration / Ensure good Hemoglobin level.
Avoiding agitation
Ketamine
Newer modalities
MgSO4
Mechanism of Action Antagonizes translocation of Ca across cell
membrane, leads to SM relaxation and Inhibits degranulation of mast cells
Decreases release of ACH (decreases excitability of muscle fibre membranes)
Side Effects: Facial warmth/flushing, hypotension, nausea, emesis,
muscle weakness, sedation, loss of DTRs, resp depression
Dose: 20-40mg/kg IV over 30 min
• The decision to intubate pt in SA , is made on the basis clinical
deterioration,
• Altered level of consciousness
• Exhaustion / P. paradoxus
• Inability to protect airway
• Increasing arterial PCO2.
• Quiet chest, absence of audible wheezing
• PaO2 < 60 mmHg : not responding to adequate oxygenation
• PaCO2 > 50 mmHg and rising more than 5 mmHg/ hour
• Zimmerman et al, reported that one or
more complications occurred in 46% of
intubated asthmatics.
• More than one-third of all complications
occurred during intubation.
• 47 % of complications during the
intensive care unit stay
• Difficult and esophageal intubations
occurred in about 15% of all patients
Standard preparation for rapid sequence
intubation .
cardio-respiratory and blood pressure
monitoring
Assistance
monitoring of oxygen saturation
careful aspiration of oropharynx
bag and mask ventilation with 100% oxygen
emptying of the stomach by nasogastric tube
benzodiazepine should be considered (e.g.,
midazolam 0.1 - 0.2 mg/kg) permitting
relaxation during preoxygenation
Ketamine hydrochloride (1 to 3 mg/kg)
Good choice for its sedative and
analgesic effects as well as its
bronchodilating characteristics.
Concomitant use of a benzodiazepine
can suppress the dysphoric effects of
Ketamine.
Ketamine increases laryngeal secretions
but does not block pharyngeal and
laryngeal reflexes, increasing the risk of
laryngospasm and aspiration in the
preintubation period
Endotracheal tube…………….
largest endotracheal tube…..
lower airflow resistance
Suctioning of thick mucosal secretions
Fiber optic bronchoscopy : facilitated
A cuffed endotracheal tube
Sometimes useful even in small children
(<5 years)
when insufflation pressures become very
high (Hubert 1996).
Intubation………….
oxygenation
H2 blockers , prokinetics . atropine
Lignocaine 4 % neb. 4mg / kg ( 1ml = 40 mg )
Sedation midazolam + ketamine / cricoid
pressure
Paralysis ( Vecuronium .1 to .2 mg / kg )
Intubation
Suction
Confirmation of tube and proper fixation
Avoid positive pressure V. without cricoid P.
Proper monitoring
Oxygenation & Circulation status
Fluid bolus for circulation
Lt heart pumps what
the
right heart gives it
Ventilatory strategy
Permissive hypercapnia
low rate 50 % for the age
low pressure
Avoiding barotrauma
low pressure
Minimal PEEP
Intrinsic PEEP
Dynamic hyperinflation (DHI)
PEEP
Controversies remain about the role of PEEP in
status asthmaticus.
Majority of cases, no PEEP should be applied
during mechanical ventilation (0 3 cm H2O
maximum)
PEEP
Intrinsic PEEP
Air leak syndrome
A 'rapid sequence' for
extubation is justified
by the risk of further
bronchoconstriction
induced by the
presence of the
endotracheal tube.
• Adding adjuvant therapy despite lack of
evidence is reasonable given the risks
associated with intubation and mechanical
ventilation
• More research is required in childhood status
asthmaticus!
M. Ventilation is a BLEND of Art and science
TH
AN
KS
• Adding adjuvant therapy despite lack of
evidence is reasonable given the risks
associated with intubation and
mechanical ventilation
• More research is required in childhood
status asthmaticus!
Mechanical ventilation
• Less than 5% of patients with SA
required intubation and MV, “braman et
al, jama 1990”
• Indications: • To decrease work of breathing.
• To maintain adequate oxygenation .
• Augment alveolar ventilation in face of airway
edema and diffuse mucus plugging of of the
small airways…
Indications of mechanical ventilation
Not governed by numbers but by the clinical conditions.
PaO2 < 60 mmHg or cyanosis not corrected by oxygen administration
PaCO2 > 50 mmHg and rising more than 5 mmHg/ hour
The decision to intubate and ventilate a child with status asthmaticus
is primarily based on clinical criteria:
respiratory muscle fatigue, obvious exhaustion, disappearance of
pulsus paradoxus
diminution of thoracic amplitude during respiratory movements
diminution of air entry in the lungs : quiet chest, absence of audible
wheezing
pulsus paradoxus > 20 - 40 mmHg (inspiratory decline in systolic
blood pressure)
deterioration of mental status (lethargy, agitation, confusion, coma)
diaphoresis in recumbent position
•ideal ventilator settings reduce dynamic hyperinflation
(DHI): limited minute ventilation (MV) using an
appropriately low but adequate tidal volume (Vt) and
respiratory rate, with an extended expiratory time (TE)