Which valve does a nurse Auscultate when the stethoscope is placed on the second intercostal space at the left of the sternal border?

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Normal heart sounds
Using a stethoscope
Standard sites for auscultation
The procedure
Professional responsibilities

The two heart sounds and the abnormal murmurs are caused by turbulence and vibrations inside the ventricles, the aorta or the pulmonary trunk.

From: Human Anatomy, 2008

Sara Morgan Lecturer, Faculty of Life Sciences, University of South Wales, Pontypridd, Mid Glamorgan, Wales

Rationale and key points

This article aims to improve nurses’ knowledge and understanding of the procedure for auscultating heart sounds in adults, as part of a cardiovascular examination. It focuses on auscultating normal heart sounds; it is beyond the scope of this article to discuss the pathophysiology of abnormal findings.

A stethoscope is used to auscultate for heart sounds. The diaphragm of the stethoscope is used to identify high-pitched sounds, while the bell is used to identify low-pitched sounds.

There are two normal heart sounds that should be elicited in auscultation: S1 (lub) and S2 (dub).

The practitioner should listen over each of the four main heart valve areas: the aortic, pulmonary, tricuspid and mitral valve areas. They should also listen for any additional sounds such as clicks, and heart murmurs.

Reflective activity

‘How to’ articles can help update your practice and ensure it remains evidence-based. Apply this article to your practice. Reflect on and write a short account of:

How you think you could use this article to improve your practice in undertaking cardiac examinations.

How you could use this resource to educate your colleagues about auscultating for heart sounds.

Nursing Standard. 32, 5, 41-43. doi: 10.7748/ns.2017.e10965

Correspondence

Conflict of interest

None declared

Peer review

This article has been subject to external double-blind peer review and checked for plagiarism using automated software

Received: 21 July 2017

Accepted: 08 August 2017

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The heart controls the movement of blood throughout the body through the use of its muscular walls to pump blood forcefully. This pump works alongside another very important set of structures, the valves, to make sure the blood is being sent the right way.

The heart is divided into four chambers where blood collects before being sent off on a journey around the body. As the heart muscle contracts, pressure in each chamber increases and blood is forced out by any possible route. It is the presence of four valves, one in each chamber, that prevent blood flowing back to where it came from ?

As pressure builds in the chambers during contraction, the valves are snapped closed very quickly, giving off the distinctive sound you hear when you listen to someone’s heartbeat! ??

Listen close enough and you can actually hear each valve individually. This is made possible through the use of a stethoscope. ? Placing it over a very specific location on the chest wall, you can actually identify the noise created by the closing of each specific valve.

Let’s now take a closer look at the points of auscultation for each valve:

The 4 auscultation points of the heart

On the right side:

The aortic valve can be heard in the 2nd intercostal space along the edge of the sternum
The tricuspid can be heard a little lower in the 5th intercostal space

And on the left side:

The pulmonary valve can be heard opposite the aortic valve, in the 2nd intercostal space along the edge of the sternum
The mitral valve can be heart in the 5th intercostal space a little more laterally, in the midclavicular line.

Clinically, listening to the valves can give us an appreciation of the structure and functionality of each valve. Conditions affecting the valves can prevent them from closing completely and cause a disruption to the sound, often called a heart murmur.

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VOL: 103, ISSUE: 27, PAGE NO: 24

Phil Jevon, PGCE, BSc, RN, is resuscitation officer/clinical skills lead and honorary clinical lecturer, University of Birmingham Medical School

Alan Cunnington, FRCP, MD, is consultant physician; both at Manor Hospital, Walsall

There is no consensus on what constitutes the correct routine in auscultation of the heart (Cox and Roper, 2005) so the key principles of the procedure will be described in detail.

Normal heart sounds, related physiology and use of the stethoscope will also be discussed. Next week, abnormal heart sounds will be outlined.

Auscultation of the heart is undertaken to establish whether the heart sounds are normal and if there are any additional sounds (Scott and MacInnes, 2006). It is a skill that requires detailed knowledge, practice and experience to ensure competency at distinguishing what is normal and abnormal.

The priority is to master the recognition of normal heart sounds; then it will be possible to identify abnormal heart sounds (Cox and Roper, 2005).

Normal heart sounds

The heart sounds are usually described as ‘lub-dup’. The first heart sound (‘lub’), which is often referred to as S1, is due to closure of the mitral and tricuspid valves and is best heard at the apex. It corresponds to the beginning of ventricular systole (Waugh and Grant, 2006). Sometimes splitting of the first heart sound occurs, which is normal.

The second heart sound (‘dup’) - often referred to as S2 - is slightly higher pitched. It is due to the closure of the aortic and pulmonary valves and is best heard in the second/third intercostal space, at the left sternal edge. It corresponds to the end of ventricular systole and the beginning of atrial systole. Splitting of the second heart sound can occur upon inspiration.

After S2 there is a short gap before the heart sounds of the next cardiac cycle; this is ventricular diastole and signifies the time when the ventricles are filling with blood (Scott and MacInnes, 2006).

Using a stethoscope

The stethoscope was introduced into medicine 200 years ago. Originally it was a wooden cylinder with a hole drilled from one end to the other. The modern stethoscope has two earpieces, which are connected by tubing to a chest device usually consisting of a bell and a diaphragm. The earpieces should be angled forwards, that is in the same direction as the practitioner’s external auditory meati (Epstein et al, 2003).

The functions of the stethoscope are to:

- Transmit sounds from the patient’s chest;

- Exclude extraneous noise;

- Selectively emphasise sounds of certain frequencies, allowing the practitioner to concentrate on them (Epstein et al, 2003).

The stethoscope should be correctly used, as the diaphragm and bell amplify different sounds (Scott and MacInnes, 2006). The diaphragm (Fig 1) is used to detect high-pitched sounds, for example S1, S2 and some murmurs, and should be pressed firmly against the skin. The bell (Fig 2) is used to detect low-pitched sounds such as the mitral stenosis murmur. It should be placed very lightly against the precordium otherwise it will, effectively, be a diaphragm (Scott and MacInnes, 2006; Cox and Roper, 2005).

Standard sites for auscultation

According to Scott and MacInnes (2006) and Cox and Roper (2005), the standard sites for auscultation of the heart are (Fig 3):

- Mitral area - left fifth intercostal space, mid-clavicular line. This is where the mitral valve sounds are best auscultated;

- Tricuspid area - left fourth intercostal space, just lateral to the sternum. This is where the tricuspid valve sounds are best auscultated;

- Pulmonary area - left second intercostal space, just lateral to the sternum. This is the area where sounds from the pulmonary valve are best auscultated;

- Aortic area - right second intercostal space, just lateral to the sternum. This is where the aortic valve sounds are best auscultated.

The procedure

Recommendations for auscultation of the heart vary. The following procedure is based on Cox and Roper (2005):

- Explain the procedure to the patient;

- While ensuring privacy and maintaining dignity, expose the patient’s chest;

- Position the patient supine at an angle of 45 degrees;

- Ensure the room is quiet;

- Ask the patient to breathe in and breathe out normally;

- Using the diaphragm, auscultate over the mitral area (Fig 4);

- Identify the S1 and S2 sounds. To assist identification of these heart sounds, it may be necessary to palpate the carotid pulse at the same time as this will coincide with the first heart sound (Ford et al, 2005) (Fig 5);

- Ask the patient to roll slightly into a left lateral position and, using the bell, auscultate over the mitral area (Fig 6). This is the best position and method to auscultate the low-pitched mid-diastolic murmur of mitral stenosis.

This article has been double-blind peer-reviewed

Professional responsibilities

This procedure should be undertaken only after approved training, supervised practice and competency assessment, and carried out in accordance with local policies and protocols.