Acute Biochemical, Cardiovascular, and Autonomic Response to Hyperbaric (4 atm) Exposure in Healthy Subjects.

Mariusz Kozakiewicz,Joanna Slomko,Katarzyna Buszko,Pawel Zalewski,Wladyslaw Sinkiewicz,Jacek J Klawe,Malgorzata Tafil-Klawe,Julia L Newton

doi:10.1155/2018/5913176

Abstract

The aim of this study was to explore the effect of a hyperbaric environment alone on the cardiovascular system by ensuring elimination of factors that may mask the effect on hyperbaria. The research was performed in a hyperbaric chamber to eliminate the effect of physical activity and the temperature of the aquatic environment. Biochemical analysis and examination with the Task Force Monitor device were performed before and immediately after exposure. TFM was used for noninvasive examination of the cardiovascular system and the functional evaluation of the autonomic nervous system. Natriuretic peptides were measured as biochemical markers which were involved in the regulation of haemodynamic circulation vasoconstriction (urotensin II). L-arginine acted as a precursor of the level of the nitric oxide whereas angiotensin II and angiotensin (1–7) were involved in cardiac remodeling. The study group is comprised of 18 volunteers who were professional divers of similar age and experience. The results shown in our biochemical studies do not exceed reference ranges but a statistically significant increase indicates the hyperbaric environment is not without impact upon the human body. A decrease in HR, an increase in mBP, dBP, and TPR, and increase in parasympathetic heart nerves activity suggest an increase in heart afterload with a decrease in heart activity within almost one hour after hyperbaric exposure. Results confirm that exposure to a hyperbaric environment has significant impact on the cardiovascular system. This is confirmed both by changes in peptides associated with poorer cardiovascular outcomes, where a significant increase in the studied parameters was observed, and by noninvasive examination.

Highlights

Diving exposes a body to an unnatural hyperbaric environment which can lead to increased gas dissolved in the tissues [1]
When peptide measurements taken before and after hyperbaric exposure were compared among the 18 participants, a statistically significant increase was seen in both atrial Atrial natriuretic peptide (ANP) and ventricular Brain natriuretic peptide (BNP)
When cardiovascular and autonomic parameters were measured at rest in the 18 participants there were significant reductions in heart rate and cardiac index and significant increases in diastolic and HR [n/1] sBP [mmHg] dBP [mmHg] mBP [mmHg] SI [ml/m2] CI [l/min/m2] TPRI [dyn ∗ s ∗ m2/cm5] IC [1000/s] Acceleration index (ACI) [100/s2] HI [1/s2] LVWI [mmHg ∗ l/[min ∗ m2]] LVET [ms] PEP [ms] ER [%]

Summary

Introduction

Diving exposes a body to an unnatural hyperbaric environment which can lead to increased gas dissolved in the tissues [1]. Gas solubility in tissues is a very complex process which cannot be described using Henry’s law being a law used for gas solubility in liquids. The complexity of these processes which take place in the diver’s organism during descending and ascending does not allow for its full theoretical description [1, 2]. Hyperbaric oxygen treatment is used for treatment of decompression sickness, carbon monoxide poisoning, gas gangrene, soft tissue [3,4,5], postradiation burns, and treatment of poorly healing wounds [6]. Studies have investigated the use of HBO after radiation or chemotherapy [7, 8], and today there are many clinical indications for the use of HBO therapy [9]

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