Hemodynamic Effects of Flexible Fiberoptic Bronchoscopy Performed under Topical Anesthesia

Hemodynamic Effects of Flexible Fiberoptic Bronchoscopy Performed under Topical Anesthesia * Rune Lundgren, M.D.;t SOren Hiiggmask; M.D4 and Sebastian Reiz, M.D.t

Central hemodynamics and blood gases were measured continuously during flexible 8beroptic bronchoscopy performed under topical anesthesia in ten patients with restrictive lung disease. De procedure induced marked hemodynamic changes, which were muimal and similar in magnitude, during passage through the larynx and during suctioning. Mean arterial pressure increased by 30 percent, heart rate by 43 percent, cardiac index by 28 percent and mean pulmonary arteriolar occlusion pressure by 86 percent compared with pre-bronchoscopic

control values. A slight faU in arterial oxygen teuslou WlL'i melL'iUred during bronchial suctioning and in the post-bronchoscoplc period. Rate pressure product reached its highest value during bronchial suctiontnc at which time three of the ten patients developed ST·T· segment changes, implying that myocardial oxygen demand might have exceeded supply. It is suggested that the major mechanism behind the hemodynamic changes is a reflex sympathetic discharge caused by mechanical irritation of larynx and bronchi.

Flexible fiberoptic bronchoscopy (FFB), usually performed under topical anesthesia, is considered a safe procedure. 1 Consequently, an increasing number of patients with impaired cardiopulmonary function are subjected to examination with this method. Severe complications have, however, been reported during FFB. 24 Besides laryngospasm, bronchospasm, endotracheal bleeding, pneumonia, pneumothorax and hypoxemia.r" several cardiovascular complications such as hypotension, dysrhythmias, and cardiac arrest have been reported in association with FFB.2,4,5 Apart from studies on cardiac rhythm,7-9 no investigations have been performed to elucidate the effects of FFB under topical anesthesia on the cardiovascular system. The aim of the present investigation was, therefore, to study the effects of FFB performed under topical anesthesia, on central hemodynamics, ECG and blood gases in patients with restrictive lung disease.

Hemodynamic and Blood Gas Measurements

MATERIAL AND METIIODS

Material Ten patients with pulmonary 6brosis scheduled for diagnostic 6beroptic bronchoscopy were investigated, with their informed consent. The study was approved by the Ethics Committee of the University of Umea. All patients were in medically optimal condition, hemodynamically stable and in sinus rhythm. Clinical data are given in Table 1. -From the University Hospital, Umea, Sweden. Department of Lung Medicine. Department of Anesthesia and Critical Care Medicine. Manuscript received December 16; revision accepted April

l

7.

Reprint requests: Dr. Lundgren, Department of Lung

cine, University Hospital, S90185 Umea, Sweden

Medi-

The patients were catheterized with a 7F balloon-tipped pulmonary artery thermodilution catheter inserted via the right internal jugular vein and wedging in the right lower lobe pulmonary artery, as cheeked by fluoroscopy. A 14G Teflon arterial catheter for arterial pressure monitoring was inserted into the right femoral artery and a 16G heparinized Silastic catheter for continuous mass spectrometric blood gas analysist! was inserted through the 14G catheter. All pressure monitoring orifices were flushed with normal saline solution (Intraflo CFS-6 R ) . ECG (lead V 5 ), arterial, pulmonary arterial and right atrial pressures were recorded continuously throughout the procedure with Siemens-Elema pressure transducers 746/51 on a Mingograph 82 recorder. The transducers were calibrated with water standards at midchest (0 - levels) and 50 mm Hg. Cardiac output was determined by the thermodilution methodw (Cardiovascular Instruments CVI 600), using a pneumatic pump, delivering 5 ml of ice cold normal saline solution in 1.5 sec for each measurement. Triplicate values not differing more than ± 5 percent were used. The thermodilution curves were recorded on the Mingograph and judged before the values were accepted. The arterial oxygen and carbon dioxide tensions were recorded continuously from the mass spectrometer (Medshield MS2 ). In addition, arterial blood samples were analyzed before, during and after FFB to checlc the stability of the blood gas catheter. Bronchoscopic Procedures

The patients were premedicated according to age, with 0.3 to 0.75 m1 morphine-scopolamine (10 mg/ml 0.4 mg/ml) one hour prior to bronchoscopy. The examination was performed with the patient in the supine position without supplementary oxygen. After hemodynamic steady state measurements, the pharynx was anesthetized with 50 mg of lidocaine spray. The larynx, trachea and bronchi were anesthetized with a total amount of 200 mg lidocaine (20 mg/ml) via a flexible fiberoptic bronchoscope (Olympus

+

CHEST I 82 I 3 I SEPTEMBER, 1982

215

Table l-elinieIJI Data Patient

0'

Tea Pfdienaa , ............. Maximal Working· Capacity (watts)

PaOt at Rest (mm Hg)

PaCO, at Rest (mm Hg)

Pulmonary fibrosis; rheumatoid arthritis

50

86

41

73

Sarcoidosis

50

73

41

F

73

Pulmonary fibrosis

55

71

48

4

M

55

Pulmonary fibrosis; epilepsy

115

91

38

5

M

58

Scleroderma

50

78

38

6

F

58

Sarcoidosis

20

71

42

7

M

63

Neurofibromatosis; pulmonary fibrosis; chronic bronchitis; emphysema

30

64

36

8

M

68

Sarcoidosis; lung cancer (status post left upper lobe resection); status post pulmonary emboli and myocardial infarction

75

71

33

9

F

67

Pulmonary fibrosis; hypertension

60

65

43

10

M

61

Asbestosis; status postlarynx cancer

115

84

No.

Sex

Age

1

F

62

2

F

3

~

Diagnosis

-Maximal working capacity according to StrandeD. II

Topical anesthesia

--

Lavage Biopsies

Suctioning Lung biopsies

-

Recovery

-

ECG and pressures Cardiac output

•

• • ••• • • ••• • • • •

•j

•

• •

A

B

C 0 , 10

Mass spectrometric blood gas analysis Blood gas sampling

Points in table 2 Time

I

-10

,

j

I

0

,

•

•

j

,

20

E

,

30

A F

• j

G

,

40min

FIGURE 1. F10w chart of procedure and measurements. The mean time for bronchoscopy including topical anesthesia was 25 min (range 17 to 33 min). Four of the patients underwent transbronchial lung biopsy. A = baseline; B passage of larynx; C = completed anesthesia; D = bronchial lavage; E = suctioning; F = seven minutes after completed bronchoscopy; G 15 min after completed bronchoscopy.

=

211

=

FFB Performed under Topical AneIth.I. (Lundtlren, Hanmart, Relz)

Table S-B6... 01 , ...",. ,

Baseline (A)

.....o"de Broru:laoeeon

Bronchial Lavage (D)

Suctioning

Larynx (B)

Completed Anesthesia (C) 114±S*

l09±S*

117±6*

Passage of

MAP (mm Hg)

9S±5

124±7**

HR (bpm)

68±4

97±S**

88±5**

7±1

13±2**

10±2*

CI (Lz'min/rn")

2.5±0.2

3.2 ±0.2**

3.2 ±0.2*·

3.0±0.2**

PaO, (mm Hg)

75±3

77±3

75±3

71 ±3

MPAOP (mm Hg)

7 Min after IS Min after Completed Completed Bronchoscopy Bronchoscopy

(F)

(E)

82±5** 9±~

(0)

l00±4

98±4

9S±6**

78±5*

77±5*

12±3*

10±2*

9±1

3.3±0.1**

2.9±0.2*

2.8±0.1

67±3**

68±3*

68±3*

MAP ==mean arterial pressure; HR==heart rate; MPAOP==mean pulmonary arteriolar occlusion pressure; CI -cardiac index; PaO, == arterial oxygen tension. Results expressed 88 mean ± SEM, n == 10. *p <0.05 compared with baseline **p <0.01 compared with baseline BF-1T) • After topical anesthesia was completed, the tip

of the bronchoscope was placed in the lingula bronchus

where bronchoalveolar lavage was performed using a total amount of 50 ml of normal saline solution at body temperature. After the lavage, bronchial mucosal biopsies were taken from the left and right upper lobes, and then intermittent suctioning through the instrument channel was performed for five minutes from the different segmental bronchi. In four of the ten patients, the examination was concluded with transbronchial lung biopsies from the right lower lobe. The mean time of the bronchoscopic procedure including topical anesthesia, was 25 minutes (range 17 to 33 minutes). Hemodynamic variables and blood gas levels were observed for 15 minutes after completed bronchoscopy. A flow chart describing measurements and procedures is presented in Figure 1. Statistical Analysis

Results are expressed as means ± standard error of the mean ( SEM ). Wilcoxon's matched-pair signed-rank test was used for the statistical analysis. A P-value less than 0.05 was considered statistically significant. RESULTS

Anesthesia and passage through the larynx with the FFB induced marked increases in mean arterial pressure, heart rate, mean pulmonary arteriolar occlusion pressure and cardiac index, and these variables remained at an elevated level after completed bronchial anesthesia. Stroke volume index, systemic vascular resistance and pulmonary vascular resistance were not significantly altered. During bronchial lavage, mean arterial pressure, heart rate and cardiac index were still elevated, whereas mean pulmonary arteriolar occlusion pressure had returned almost to baseline. Five minutes of intermittent suctioning through the FFB increased these four parameters to approximately the same values as measured during passage of the larynx. A significant decrease in Pa02 was recorded during suctioning and Pa02 remained decreased through the rest of the investigation. No changes were recorded in PaC02. Fifteen minutes after bronchoscopy was

completed, all variables except heart rate and Pa02 had returned to baseline. All significant changes are listed in Table 2. There was no increased incidence of cardiac dysrhythmias in the investigated patients. ST-T-segment depressions were recorded in patient 1 during anesthesia of the larynx and in patients 1, 2 and 3 during suctioning (Table 3). None of the ten patients experienced any complications due to the investigation. DISCUSSION

Cardiovascular complications are responsible for many of the deaths reported in association with FFB." There is, however, little information available about the cardiovascular effects of FFB performed under topical anesthesia. In the present study, substantial hemodynamic changes were recorded during topical anesthesia and passage of the larynx with the FFB. During this period, there were marked increases in heart rate (43 percent), mean arterial pressure (30 percent), mean pulmonary arteriolar occlusion presTable 3--ST.T.se.rnen' Depreaion Duri,.. Flesi6le Fi6eropde Bronelao~opy (3 PadenU)

ST-T-

Patient No. RPP Baseline

MPAOP (mmHg)

segment PaOt Depressions (mmHg) >0.1 mV

I

9 600 8 800 8 400

4 7 10

86 73 71

2 3

Anesthesia and passage through larynx

2 3

I

12 000 20 000 17 400

9 10 20

86 75 68

+

Suctioning

I 2 3

25 200

12 9 30

79 65 57

+ + +

20 000

23 800

RPP-rate pressure product; MPAOP-mean pulmonary arteriolar occlusion pressure. CHEST I 82 I 3 I SEPTEMBER, 1882

287

sure (86 percent) and cardiac index (28 percent) (Table 2). Endotracheal intubation and laryngoscopy under general anesthesia are associated with a rise in heart rate and arterial pressure. 13-18 Tomori and Widdicombe 17 stimulated the laryngopharyngeal regions in paralyzed cats and noticed increased systemic blood pressure and increased sympathetic nervous activity. Following endotracheal intubation Russell et al 18 measured significant increases in mean arterial pressure and plasma norepinephrine concentration, whereas plasma epinephrine and dopamine concentrations did not change. These results suggest that intubation with the FFB is associated with an increase in sympathetic nerve activity and release of norepinephrine. A correlation between rise in PaC02 and mean pulmonary arterial pressure has been reported in association with endotracheal intubation under general anesthesia." In the present study, there was no increase in PaC02 which could have explained part of the hemodynamic changes. An increased airway pressure due to obstruction by the flexible fiberoptic bronchoscope might have influenced the transmural pressures. Investigating patients with a similar bronchoscopic procedure as in the present study, Lindholm et al20 could, however, only demonstrate small variations in intratracheal pressure during FFB. We therefore found it unlikely that the rise in mean pulmonary arteriolar occlusion pressures during passage of the larynx was a result of bronchial obstruction by the FFB. The increases in left ventricular filling pressure (approximately mean pulmonary arteriolar occlusion pressure) and cardiac output measured in association with the marked rise in systolic blood pressure is probably an expression for an upward shift on the left ventricular function curve. The rise in heart rate, mean arterial pressure and cardiac index seen as a result of passage through the larynx had fallen slightly after topical anesthesia had been completed and decreased further during bronchial lavage which was the next stage when measurements were made (Table 2). It seems likely that the continued elevation seen during bronchial lavage reflects a gradually declining effect of the passage through the larynx rather than an effect of the lavage per see Dubrawsky et al2 1 reported a significant decrease in Pa02 following bronchial washing and aspiration of 30-40 ml saline solution in the main bronchus. They suggested a ventilation-perfusion mismatching following lavage. Brach et aI,22 however, did not notice any decreased ventilationperfusion ratio after segmental lavage with 30-50 ml of normal saline solution. In our study, there was no decrease in the continuously measured 288

Pa02 during segmental lavage which was performed with 50 ml of normal saline solution. The second hemodynamically stressful period associated with FFB occurred during suctioning. Besides increases in mean ·arterial pressure, heart rate, mean pulmonary arteriolar occlusion pressure and cardiac index there was a significant decrease in Pa02 (Table 2). A possible mechanism behind the hemodynamic changes might be a sympathetic stimulation caused by movement of the bronchoscope with repeated irritation of larynx and bronchi during suctioning. Altered ventilation-perfusion ratio due to suctioning and to a lesser extent bronchoconstriction resulting from mechanical irritation of the bronchial mucosa might explain the hypoxemia during and after suctioning. In our study, rate pressure product reached its highest level during suctioning (+ 79 percent) indicating markedly increased myocardial oxygen consumption." Shortening of the diastolic coronary perfusion time and reduction of Pa02 induced a decrease in myocardial oxygen availability during suctioning when myocardial oxygen demand was markedly increased. This can lead to a mismatching between oxygen supply and demand which might explain why three of the patients developed ST-T-segment depression during suctioning. In these patients, Pa02 had decreased about 10 mm Hg and rate pressure product was approximately 2.5 times the control value (Table 3). Cardiac dysrhythmias during FFB have previously been reported as a complication associated with hypoxernia.f' However, this could not be confirmed in our study. In conclusion, our investigation has shown that FFB induces substantial central hemodynamic changes during passage of the larynx and during suctioning. In patients with cardiac disease, the increase in arterial pressure and heart rate may be dangerous, particularly if combined with impaired arterial oxygenation. It seems likely that some of the hemodynamic changes might be reduced by improved anesthetic technique. It has been shown that mouthwash and gargling with viscous lidocaine as well as intravenous lidocaine can attenuate the blood pressure response to laryngoscopy." Although effective against tachycardia, beta-blocking agents do not effectively counteract the hypertensive response to laryngoscopy. 15 Supplementary oxygen should be given during bronchoscopy and for cardiac monitoring purposes, the ECG V 5 lead is of value to detect myocardial dysoxia.24 ACKNOWLEDGMENT: This study was supported by grants from the Swedish National Association against Heart and Chest Diseases and the Medical Faculty, University of Umea, FFB Performed under Topical Anelth.la (Lundgren, Haggmark, Re/z)

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at