Use of One-Lung Ventilation for Thoracic Surgery

8/13/2019 Use of One-Lung Ventilation for Thoracic Surgery

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Use of One-Lung Ventilation

for Thoracic Surgery

Yanping Duan, M.D., CA-2

Charles Smith, M.D.

Department of Anesthesiology

MetroHealth Medical Center


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Objectives

Indication/contraindication of OLV

Physiology changes of OLV Selection of the methods for OLV

Management of common problems

associated with OLV, especiallyhypoxemia


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Introduction

One-lung ventilation, OLV, means separation of

the two lungs and each lung functioning

independently by preparation of the airway

OLV provides: Protection of healthy lung from infected/bleeding one

Diversion of ventilation from damaged airway or lung

Improved exposure of surgical field

OLV causes:

More manipulation of airway, more damage

Significant physiologic change and easily development

of hypoxemia


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Indication

Absolute Isolation of one lung from the other to avoid spillage or

contamination

Infection

Massive hemorrhage

Control of the distribution of ventilation

Bronchopleural fistula

Bronchopleural cutaneous fistula

Surgical opening of a major conducting airway

giant unilateral lung cyst or bulla Tracheobronchial tree disruption

Life-threatening hypoxemia due to unilateral lung disease

Unilateral bronchopulmonary lavage


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Indication (continued) Relative

Surgical exposure ( high priority) Thoracic aortic aneurysm

Pneumonectomy

Upper lobectomy

Mediastinal exposure

Thoracoscopy

Surgical exposure (low priority)

Middle and lower lobectomies and subsegmental resections

Esophageal surgery

Thoracic spine procedure

Minimal invasive cardiac surgery (MID-CABG, TMR)

Postcardiopulmonary bypass status after removal of totally occluding

chronic unilateral pulmonary emboli

Severe hypoxemia due to unilateral lung disease


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Physiology of the LDP

Upright position LDP, lateral decubitus position


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Physiology of LDP

Awake/closed chest Anesthetized.

V Q V Q V Q

ND

D


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Summary of V-Q relationships in the

anesthetized, open-chest and paralyzed patients

in LDP


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Physiology of OLV The principle physiologic change of OLV is the redistribution of

lung perfusion between the ventilated (dependent) and blocked(nondependent) lung

Many factors contribute to the lung perfusion, the major

determinants of them are hypoxic pulmonary vasoconstriction,

HPV and gravity.


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HPV HPV, a local response of pulmonary artery smooth muscle,

decreases blood flow to the area of lung where a lowalveolar oxygen pressure is sensed.

The mechanism of HPV is not completely understood.

Vasoactive substances released by hypoxia or hypoxia itself

(K+ channel) cause pulmonary artery smooth musclecontraction

HPV aids in keeping a normal V/Q relationship by

diversion of blood from underventilated areas, responsible

for the most lung perfusion redistribution in OLV HPV is graded and limited, of greatest benefit when 30% to

70% of the lung is made hypoxic.

But effective only when there are normoxic areas of the

lung available to receive the diverted blood flow


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Factors Affecting Regional HPV

HPV is inhibited directly byvolatile anesthetics (not

N20), vasodilators (NTG,

SNP, dobutamine, many 2-

agonist), increased PVR(MS, MI, PE) and

hypocapnia

HPV is indirectly inhibited

by PEEP, vasoconstrictordrugs (Epi, dopa,

Neosynephrine) by

preferentially constrict

normoxic lung vessels


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Gravity and V-Q

Upright LDP


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Shunt and OLV

Physiological (postpulmonary) shunt About 2-5% CO,

Accounting for normal A-aD02, 10-15 mmHg

Including drainages from

Thebesian veins of the heart

The pulmonary bronchial veins

Mediastinal and pleural veins

Transpulmonary shunt increased due to continued

perfusion of the atelectatic lung and A-aD02 may

increase


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Methods of OLV

Double-lumen endotracheal tube, DLT

Single-lumen ET with a built-in bronchial

blocker, Univent Tube

Single-lumen ET with an isolated bronchial

blocker

Arndt (wire-guided) endobronchial blocker set

Balloon-tipped luminal catheters

Endobronchial intubation of a single-lumen

ET


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DLT

Type: Carlens, a left-sided + a carinal hook

White, a right-sided Carlens tube

Bryce-Smith, no hook but a slotted cuff/Rt

Robertshaw, most widely used

All have two lumina/cuffs, one

terminating in the trachea and the other in the

mainstem bronchus Right-sided or left-sided available

Available size: 41,39, 37, 35, 28 French (ID=6.5,

6.0, 5.5, 5.0 and 4.5 mm respectively)


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Left DLT Most commonly used

The bronchial lumen is longer, and a simple round openingand symmetric cuffBetter margin of safety than Rt DLT

Easy to apply suction and/or CPAP to either lung

Easy to deflate lung

Lower bronchial cuffvolumes and pressures

Can be used

Left lung isolation:

clamp bronchial+

ventilate/ tracheal lumen

Right lung isolation:

clamp tracheal+

ventilate/bronchiallumen


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Left DLT

More difficult to insert (size and curve, cuff)

Risk of tube change and airway damage if kept in

position for post-op ventilation

Contraindication:

Presence of lesion along DLT pathway

Difficult/impossible conventional direct vision intubation

Critically ill patients with single lumen tube in situ who

cannot tolerate even a short period of off mechanical

ventilation

Full stomach or high risk of aspiration

Patients, too small (


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Univent Tube... Developed by Dr. Inoue

Movable blocker shaft in external

lumen of a single-lumen ET tube

Easier to insert and properly

position than DLT (diff airway,

C-s injury, pedi or critical pts)

No need to change the tube for

postop ventilation

Selective blockade of some lobes

of the lung

Suction and delivery CPAP to the

blocked lung


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Arndt Endobronchial Blocker set Invented by Dr. Arndt, an anesthesiologist

Ideal for diff intubation, pre-existing ETT and

postop ventilation needed

Requires ETT > or = 8.0 mm

Similar problems as Univent Inability to suction or ventilate the blocked lung


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Other Methods of OLV

Single-lumen ETT with a balloon-tipped catheter

Including Fogarty embolectomy catheter, Magill or

Foley, and Swan-Ganz catheter (children < 10 kg)

Not reliable and may be more time-consuming Inability to suction or ventilate the blocked lung

Endobronchial intubation of single-lumen ETT

The easiest and quickest way of separating one lung

from the other bleeding one, esp. from left lung

More often used for pedi patients

More likely to cause serious hypoxemia or severe

bronchial damage


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...Management of OLV

If severe hypoxemia occurs, following steps be taken Check DLT position with FOB

Check hemodynamic status

CPAP (5-10 cm H2O, 5 L/min) to nondependent lung, most effective

PEEP (5-10 cm H2O) to dependent lung, least effective

Intermittent two-lung ventilation

Clamp pulmonary artery ASAP

Other causes of hypoxemia in OLV

Mechanical failure of 02supply or airway blockade

Hypoventilation

Resorption of residual 02from the clamped lung

Factors that decrease Sv02(CO,02consumption)


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Broncho-Cath CPAP System


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Summary

OLV widely used in cardiothoracic surgery

Many methods can be used for OLV. Each of them

have advantages + disadvantages. Optimal methods

depends on indication, patientfactors, equipment,

skills + training FOB is the key equipment for OLV

Principle physiologic change of OLV is the

redistribution of pulmonary blood flow to keep anappropriate V/Q match

Management of OLV is a challenge for the

anesthesiologist, requiring knowledge, skill,

vigilance experience and practice

Use of One-Lung Ventilation for Thoracic Surgery

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