Right-to-left shunt and risk of decompression illness with cochleovestibular and cerebral symptoms in divers: case control study in 101 consecutive dive accidents.

Abstract

OBJECTIVE:

We investigated the role of right-to-left shunt with standardized transcranial Doppler ultrasonography in a large population of divers referred for symptoms of decompression illness.

DESIGN:

Case series compared with a control group.

SETTING:

Military teaching hospital, hyperbaric unit.

PATIENTS:

Patients were 101 consecutive divers with clinical evidence of decompression illness and a control group of 101 healthy divers.

INTERVENTION:

Specification of the type of decompression illness involved and detection/evaluation of right-to-left shunt by standardized transcranial Doppler. The degree of right-to-left shunt was defined as major if the number of high-intensity transient signals in the middle cerebral artery was >20.

MEASUREMENTS AND MAIN RESULTS:

We evaluated the odds ratios by logistic regression analysis with vs. without right-to-left shunt for subjects with cochleovestibular symptoms, cerebral decompression illness, spinal decompression illness, and Caisson sickness. Of the 101 divers presenting with decompression illness, transcranial Doppler detected a right-to-left shunt in 59 (58.4%), whereas control subjects demonstrated a right-to-left shunt in 25 cases (24.8%; odds ratio, 4.3; 95% confidence interval, 2.3-7.8; p=.09). When a right-to-left shunt was detected, the right-to-left shunt was major in 12 of 25 patients in the control group and in 49 of 59 patients in the decompression illness group (odds ratio, 8.7; 95% confidence interval, 4.2-18.0; p<.001). Within the decompression illness group, the proportion of major right-to-left shunt was 24 of 34 (odds ratio, 29.7; 95% confidence interval, 10.0-87.2; p<.0001) in the cochleovestibular subgroup, 13 of 21 (odds ratio, 24.1, 95% confidence interval, 6.8-86.0, p< 0.0001) in the cerebral decompression illness subgroup, ten of 31 (odds ratio, 3.9; 95% confidence interval, 1.5-10.3; p<.01) in the spinal decompression illness subgroup, and two of two (odds ratio, 1.1; 95% confidence interval, 0.2-5.7; p=.9) in the subgroup of divers with Caisson sickness.

CONCLUSION:

Based on our results, we conclude that major right-to-left shunt was associated with an increased incidence of cochleovestibular and cerebral decompression illness, suggesting paradoxical embolism as a potential mechanism.

• Authors: Emmanuel Cantais, Pierre Louge, Alain Suppini, Philip P Foster, Bruno Palmier
• Journal: Critical care medicine (Crit Care Med) Vol. 31 Issue 1 Pg. 84-8 (Jan 2003) ISSN: 0090-3493 [Print] United States
• PMID: 12544998 (Publication Type: Journal Article)

Topics

• Adult
• Case-Control Studies
• Cochlear Diseases (epidemiology, etiology)
• Decompression Sickness (diagnostic imaging, epidemiology, etiology)
• Diving (injuries)
• Embolism, Paradoxical (complications)
• Female
• France (epidemiology)
• Heart Septal Defects, Atrial (complications, diagnostic imaging)
• Humans
• Incidence
• Logistic Models
• Male
• Risk
• Ultrasonography, Doppler, Transcranial
• Vestibular Diseases (epidemiology, etiology)