smoke inhalation...smoke inhalation station night club fire rhode island february 20, 2003 100...

11/6/2013

1

Smoke inhalation

Craig Smollin MDAssociate Medical Director,

California Poison Control Center, SFAssistant Professor of Emergency Medicine

University of California, San Francisco

Disclosures

• No financial relationship to any commercial products discussed in this talk

• Fires account for approx 3,250 U.S. deaths/yr

• Majority due to smoke inhalation

• Associated with high morbidity and mortality

Smoke Inhalation

Station night club fireRhode IslandFebruary 20, 2003

100 killed230 injured

11/6/2013

2

Kiss nightclub fireJan, 2013

233 killedMany from smoke inhalation

Case Study

• 40-year old male pulled from an enclosed fire.

He is confused and agitated. He arrives in your

emergency department disoriented and in

moderate distress, coughing up soot and

complaining of difficulty breathing.

• VS: BP 90/60, HR 120, RR 30, O2 sat 95%

From http://lifeinthefastlane.com/

What type of injuries do you expect?

• Thermal burns to the upper airway

• Chemical injury to the upper airway

• Chemical injury to the lower airway

• Systemic affects of absorbed poisons

11/6/2013

3

Objectives for this talk

• We will focus on the systemic toxicity of inhaled toxic gases

• Carbon Monoxide

• Cyanide

Carbon monoxide (CO)

• Colorless, odorless, non-irritant gas

• Produced anytime a carbon-containing substance is burned

• House fires, leaking furnaces, portable generators

Carbon monoxide (CO)

• Common serious poisoning

• 15,000 - 40,000 cases/year in U.S

• Over 2,000 deaths

• High incidence of permanent neurologic sequelae

CO Pathophysiology

11/6/2013

4

Hemoglobin

Oxygen

Carbon Monoxide

CO-Hgb

11/6/2013

5

1. Functional Anemia 2. Shift in Oxygen HgbDissociation Curve

40 80 1200

50

100

Oxygen Partial Pressure (mmHg)

Per

cent

Sat

urat

ion

Hgb

40 80 1200

50

100


Per

cent

Sat

urat

ion

Hgb

alveoli

11/6/2013

6

40 80 1200

50

100


Per

cent

Sat

urat

ion

Hgb

alveolitissues

40 80 1200

50

100


Per

cent

Sat

urat

ion

Hgb

alveolitissues

40 80 1200

50

100


Per

cent

Sat

urat

ion

Hgb

alveolitissues

40 80 1200

50

100


Per

cent

Sat

urat

ion

Hgb

alveolitissues

11/6/2013

7

40 80 1200

50

100


Per

cent

Sat

urat

ion

Hgb

alveolitissues

CO Pathophysiology

• Binds to hemoglobin

• 250:1 compared wtih O2

• Functional anemia

• Changes hemoglobin such that it wont give up oxygen

CO Pathophysiology• Binds to hemoglobin

• 250:1 compared wtih O2

• Functional anemia

• Shifts O2-Hemoglobin dissociation curve to left

• Other toxic effects

• Intracellular myoglobin?

• Intracellular cytochrome?

• Post anoxic inflammatory injury

Symptoms and Signs

• Nonspecific

• Headache

• Dizziness

• Malaise

• Nausea and vomiting

• Confusion

11/6/2013

8

Pitfall

• The diagnosis of carbon monoxide poisoning is easily overlooked!

Clues to the diagnosis

Cherry-red color

Multiple victims

Pulse oximetry?

ABGs?

Pulse oximetry

Pitfall - Pulse oximetry reading will be normal in CO poisoning

Arterial blood gas

Pitfall - pO2 by arterial blood gas will be normal in CO poisoning

11/6/2013

9

Traditionally CO only measurable through CO-oximetry

Pearl

CO-oximetry can be performed on either venous or arterial blood samples

Clues to the diagnosis

Cherry-red color

Multiple victims

Pulse oximetry?

ABGs?

Pearl

You must have a high index of suspicion and send a CO-Hgb level by CO-oximetry

11/6/2013

10

Carboxyhemoglobin levels

COHgb %< 5%

10-20%

30-40%

40-50%50-60%

Symptoms*None, or mild headacheHeadache, dyspnea on

exertionSevere headache, fatigue,

irritability, dizziness Confusion, collapseComa, convulsions

*Note: correlation between COHgb levels and symptoms is poor

Outcome after CO Poisoning

• Survivors of severe poisoning may have permanent “hard” sequelae.

• Vegetative state

• Parkinsonism

• Survivors of severe poisoning may have permanent “hard” sequelae.

• Vegetative state

• Parkinsonism

• Subtle cognitive deficits

• Memory impairment

• Irritability

• Moodiness

• Difficulty concentrating

Outcome after CO Poisoning Case Continued...

• Laboratory Data:

• VBG: pH 6.8, pO2 = 75,

• Lactate = 16 mmol/L

• COHgb = 20%

• CXR negative

• Head CT negative

11/6/2013

11

Pitfall

•Tendency to focus on CO as the diagnosis

San Francisco 1906 - Great Earthquake and Fire

Question: are there any other systemic toxins found in smoke?

Consider this…

• Hydrogen cyanide gas produced in combustion of :

Consider this…

• Hydrogen cyanide gas produced in combustion of :

• Probability of HCN production/exposure is high

Paper Silk Wool Plastic Cotton

11/6/2013

12

Pitfall

Dont forget about Cyanide !!Patients exposed to carbon monoxide are

likely to be exposed to cyanideCyanide: Pathophysiology

Electron Transport Chain

Mitochondrial Matrix


NADH

e-

11/6/2013

13


NADH

e- H+ H+ H+


NADH

H+ H+ H+

e-


NADH

H+H+H+ADP ATP


NADH

ADP ATP

cytochrome aa3

CN

11/6/2013

14


NADH

ADP ATP

cytochrome aa3

CN

Symptoms and Signs

• Dizziness

• Headache, nausea, vomiting

• Dyspnea

• Tachycardia, hypotension

• Coma, seizures, death

Pitfall

• Cyanide levels are not readily available!

Clinical clues to the diagnosis

Lactic Acidosis

Elevated mixed venous pO2

Cardiovascular collapse

11/6/2013

15

Pearl

Consider CN toxicity in the smoke inhalation patient with lactate > 10

Case Continued...

Our patient likely exposed to both CO and CN!

Laboratory Data:

VBG: pH 6.8, pO2 = 75,

Lactate = 16 mmol/L

COHgb = 20%

CXR negative

HCT negative

Treatment Which of the following treatments should be rendered to our patient?

• (A) Nitrites

• (B) Sodium thiosulfate

• (C) Hydroxocobalamin

• (D) Hyperbaric oxygen therapy

11/6/2013

16

Treatment of CN Poisoning

• Removal from source

• 100% oxygen by tight-fitting mask/ET tube

• Cyanide antidote kit?

• Hydroxocobalamin?

Cyanide Antidote Kit

Cyanide Antidote Kit Nitrites

11/6/2013

17

Nitrites Nitrites

Nitrites

Problem:

(1) Hypotension

(2) Methemoglobinemia

Pitfall

• Administration of nitrites to thepatient with concurrent CO and CNpoisoning

11/6/2013

18

Cyanide Antidote Kit Sodium thiosulfate

Sodium thiosulfate Hydroxocobolamin

• Combines with CN to form Vitamin B12.

• Appears to be effective and safe

• Preferred drug for CN due to smoke inhalation (safer than nitrites)

11/6/2013

19

73

Hydroxocobolamin

• Side effects:

– Red Skin, secretions 2-7 days

– Nausea, vomiting

– Occasional HTN and muscle twitching

from Clin Toxicol 2006; 14.17

Treatment of CO Poisoning

• Removal from source

• 100% oxygen by tight-fitting mask/ET tube

• Hyperbaric oxygen?

Oxygen Treatment Approx T1/2 of COHgb

¥ Room air 5-6 hrs¥ 100% Oxygen 45-90 min¥ Hyperbaric oxygen 20-30 min

Hyperbaric oxygen• Speedier removal of CO

• Provides oxygen independent of Hgb

• Benefit to the injured brain?

• About 1500 patients treated/year in U.S.

• Million dollar question:

• Does HBO therapy reduce the incidence of subtle cognitive deficits?

11/6/2013

20

Multiplace chamber - Jacobi Hospital NYMultiplace chamber - Jacobi Hospital NY

Monoplace chamberMonoplace chamber

Weighing the Evidence: HBO vs NBO

YES NO

Thom et. al.

Weaver et al.

Raphael et. al

Scheinkestel et. al.

YES NO

Thom et. al.

Weaver et al.

Raphael et. al

Scheinkestel et. al.

?

Naturally, experts disagree on interpretation!

Weighing the Evidence: HBO vs NBO

11/6/2013

21

Consider HBO if:

• Loss of consciousness (1,2)

• COHbg > 25% (1,2)

• Age > 36 yrs (1)

• Metabolic acidosis

• Cerebellar findings on Exam (2)(1) Weaver et al: Am J Resp Crit Care Med 2008; 178:314(2) Weaver et al: NEJM 2002; 347:1057

• Also, pregnancy (fetus more at risk)

Which of the following treatments should be rendered to our patient?

• (A) Nitrites

• (B) Sodium thiosulfate

• (C) Hydroxocobalamin

• (D) Hyperbaric oxygen therapy

Which of the following treatments should be rendered to our patient?

• (A) Nitrites (no)

• (B) Sodium thiosulfate (maybe)

• (C) Hydroxocobalamin (probably better)

• (D) Hyperbaric oxygen therapy (consider)

Case Conclusion...

Patient intubated and placed on 100% oxygen.

Received hydroxocobalamin for presumed CN

exposure (lactate >10 mmol/L). HBO was

considered but decided against because

nearest chamber was at great distance and

patient unstable.

11/6/2013

22

Take home points

• Carbon monoxide

• Nonspecific symptoms

• pO2 and conventional pulse ox normal

• Treat with oxygen

• Consider HBO

Take home points• Cyanide

• Often accompanies CO in smoke inhalation

• Elevated lactate and mixed venous pO2

• Avoid nitrites in smoke inhalation victims

• New antidote: hydroxocobalamin

Questions?

smoke inhalation...smoke inhalation station night club fire rhode island february 20, 2003 100...

Documents