Prof. W. Bachmann The handicapped nose breathing Basic diagnostics: Anamnesis, inspection, rhinomanometrics and allergology Prof. Dr. W. Bachmann ATMOS MedizinTechnik GmbH & Co. KG Kaiser-Wilhelm-Straße 5 Ludwig-Kegel-Straße 16 76530 Baden-Baden 79853 Lenzkirch Germany Germany phone +49 7653 689-0 fax +49 7653 689-190 „Obstructed nasal breathing” [email protected] All rights reserved www.atmosmed.com 2 Preface Measurement of nasal resistance, especially, has taught us in recent years to understand better the associations between the form and function of the nose. This is still true today. Without comparing the patient’s history and findings on inspection with the measurements of resistance, a functional assessment of narrow points and anatomical abnormalities cannot be made. Error-free investigation and treatment of obstructed nasal breathing can often be achieved only by the precise quantification and differentiation of nasal resi- stance (constant anatomical resistance, variable turbinate resistance, the ratio between the two sides, flow increase etc.) with the aid of rhinomanometry. In recent years, the diagnostic process has become standardised. Unfortunately, however, there has hitherto been no short practical introduction to: . rhinomanometry and the sources of error . history, inspection and rhinomanometry as a diagnostic unit . basic features of the investigation of nasal allergies and hyperreactivity . basic clinical and functional anatomical information I hope that this brief introduction, limited to what is important and accepted will prove useful for rhinologists, allergists, pulmonologists, occupational and sports physicians and medical technical staff both as an introduction and as a reference book for routine clinical practice. August 2000 Prof. W. Bachmann 3 Table of contents 1.0 Introduction: why rhinomanometry? 6 2.0 Nasal resistance 2.1 Nasal resistance graphs: respiratory pliers, spread, quantification 8 2.2 Physiological spread, representative graph 9 2.3 Quantification of nasal resistance, 2 parameters 9 2.3.1 Clinically oriented parameters: V150 and Δ V% 10 2.3.2 Equivalent tube sizes 11 3.0 Performing rhinomanometry 3.1 Structure and mode of function of a rhinomanometer 12 3.2 Guidelines on performing rhinomanometry 13 3.3 Anterior measurement of choanal pressure with adapter 15 3.4 Posterior measurement of choanal pressure with oral probe 16 3.5 Synchronous measurement of pressure difference and flow through half-mask with measuring tube 17 4.0 Investigation of obstructed nasal breathing 4.1 The nose as flow channel: form and function as one unit 18 4.2 Clinically important basic concepts 21 4.3 Three leading symptoms (often in combination), important groups of illnesses 23 4.4 History: basic investigations 24 4.5 Anterior and posterior rhinoscopy (endoscopy). Basic investigations 25 4.6 Rhinomanometry (basic investigations) 26 4 5.0 Nasal hyperreactivity 5.1 Definition, pathomechanisms 29 5.2 Non-allergic hyperreactive rhinitis 30 5.3 The allergic type I reaction (hyperreactivity in 3 phases) 32 5.3.1 Clinically important basic data concerning nasally acting allergens (3 groups) 33 5.3.2 Baseline investigations to find the current allergen 36 5.3.3 Allergy history (family, personal, symptoms, environmental history) 36 5.3.4 Targetted search for the current allergen by classifing the predominant symptoms into 4 main groups 38 5.3.5 Skin testing – RAST 39 5.3.6 Emergency treatment of allergic incidents 42 5.3.7 Nasal provocation 43 5.3.8 Investigation of oral allergens with nasal symptoms (cross allergies, pseudo-allergies) 47 6.0 Appendix 6.1 Brief history of rhinomanometry 49 6.2 Conclusion 49 References 50 6.4 Division of rhinomanometric measuring curves 32 6.5 Flow SUM ............................................................................................................... 32 6.6 Flow INC ................................................................................................................. 32 5 1.0 Introduction: Why rhinomanometry? Evaluation of nasal resistance is difficult, as it is a parallel, alternating and partial resistance of the entire airways, and it also possesses a bypass – mouth brea- thing. Obstructed nasal breathing can be caused by different factors, alone or in combination. Assessment of nasal resistance by the patient is often incorrect and misleading because of his lack of knowledge of the physiological and pathological relations. Assessment by inspection, endoscopy or acoustic rhinometry is reliable only in extreme cases, since an exact quantitative conclusion about the measurab- le patency cannot be drawn from the measured cross section because of the complicated flow physics. Quantification by rhinomanometry is therefore essential! This is the only me- thod that allows: . distinguishing of anatomical defects of the supporting skeleton, hyperreac- tivity, non-nasal factors in mouth breathing and erroneous subjective assessment when there are combined causes, . determination of objective operative indications (nonphysiological bottle- necks, anatomical defects increasing turbulence or narrowing the lumen, turbinate factors, side asymmetry), . clarification of operative contraindications (nasal cavity too wide), . confirmation of the current state of nasal allergies by measuring the reduction in flow after nasal provocation, . support for the diagnosis of nasal hyperreactivity by clarifying the turbinate factor and excluding nasal allergens by provocation, . objective identification of non-nasal factors (oral, dental, jaw anomalies, pulmonary, cardiac dyspnoea, psychological factors) in mouth breathing by obtaining normal measurements, . identification of false subjective estimates of patency by comparing with the measurements, 6 . quantification of alterations in patency after: . diagnostic measures (resolving swelling, provocation etc.) . therapeutic measures (operative, medical, physical) . experimental measures (hot and cold stimuli, changes of position). 7 2.0 Nasal resistance 2.1 Nasal resistance graphs: Respiratory pliers, spread, quantification Nasal resistance is a preset regulatory resistance for the optimum ventilation of the sinuses, ears and lungs. It is greater than lung resistance, hence its clinical importance and the indispensability of measuring it! . Figure 1. “Respiratory Flow V (cm³/s) pliers” according to Exspiration li. Inspiration re. BACHMANN using an- terior measurement = ∆ p (Pascal) right and left side pre- sent a mirror image. Ter- minology: international Exspiration re. Inspiration li. standard, see also page 16. Typically curved resistance graphs as a result of the resistance changing during a breath. (simple quantification is therefore impossible.) . Principle of measurement: synchronous measurement of 2 parameters: Pressure difference Δ p (Pascal) between nasal opening and choana. Flow V. (cm³/s) = volume of air flowing through each cross section per second or per minute. Analysis: flow at 75, 150, 300 Pascal. Roughly: . The smaller V. 150, the closer the graph is to the x axis, the greater the unilateral resistance and the lower the nasal patency. The lower V.150 bilat, the narrower the respiratory pliers and the greater the total resistance. False graphs see page 13. 8 2.2 Physiological spread, representative graph Several breaths in one measurement have a scatter of up to 15%. However, a single representative graph is required for quantification. Since outliers of- ten occur, simple averages are insufficient. It should be stated in describing the device what method is used for drawing a representative graph (weighting, re- gression graph, CAR etc). The representative graphs of immediately repeated measurements can have a scatter of up to 15 %. 2.3 Quantification of nasal resistance, 2 parameters Quantification of the resistance graph is problematic, since it has 3 phases: . A purely laminar initial phase. This is extremely brief (approx. 0 - 30 cm³/s flow) and therefore clinically insignificant. This is also an area of very high measurement precision. A large laminar-turbulent mixed phase due to increasing turbulence. It is the most important zone physiologically. An end phase. There is individual variation, and it has either a still obvious laminar component or is predominantly turbulent or completely turbulent or demonstrates inspiratory narrowing of the lumen with an increasingly straight-line graph. For diagnosis 2 parameters which allow a comparison are sufficient: . with the history to clarify subjective false estimates . with inspection to elucidate: . pathological bottlenecks (i.e. narrower than a normal isthmus, page 18). anatomical defects (deviations, spines etc.), which disturb the flow as the pressure difference increases due to turbulence, deflection, eddies etc. anatomical defects which cause inspiratory narrowing of the lumen (valve stenosis). 9 2.3.1 Clinically oriented parameters: V.150 and Δ V% (BACHMANN, BACHERT) Both are clear and easy to measure as they simply quantify the increase in flow between 0 and 150 and 150 and 300 Pascal and compare it with a purely lami- nar flow (figure 2). They can be read directly from the graph or printed as a table with graph. They allow a conclusion to be drawn about the type of flow (laminar, turbulent, mixed) and its causes (bottlenecks, anatomical defects) and to iden- tify subjective false estimates. V 150, the increase in flow between 0 and 150 Pascal. It is dominated by the narrowest point and is the inverse of the 4th-5th power of the hydraulic diameter*). Relative