The S/Z ratio: A simple and reliable clinical method of evaluating laryngeal function in patients after intubation

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dc.contributor.authorVan der Meer G.
dc.contributor.authorFerreira Y.
dc.contributor.authorLoock J.W.
dc.date.accessioned2011-05-15T16:16:57Z
dc.date.available2011-05-15T16:16:57Z
dc.date.issued2010
dc.description.abstractObjectives: 1. To determine the consequences of prolonged intubation on laryngeal function.2. To evaluate simple clinical criteria or tests that could alert the clinician to potential laryngeal pathology requiring ear, nose, and throat/otolaryngology (ENT) referral. Design: A prospective case series. Setting: A surgical intensive care unit in a tertiary academic hospital in Cape Town, South Africa. Participants: Thirty-two patients who had undergone a period of translaryngeal intubation for a period greater than 12 hours. Main outcome measures: 1. Patient subjective voice change rating.2. Clinician assessment of laryngeal function.3. S/Z ratio.4. Presence of laryngeal pathology on endoscopic assessment of the larynx. Results: Upon initial evaluation within 6 hours of extubation, 26 (81%) of patients exhibited symptomatic laryngeal dysfunction. At this stage, 13 (40%) had S/Z ratios greater than 1.4. The degree of dysfunction as described by subjective scoring and the S/Z ratio was proportional to the duration of intubation. After 24 hours, 23 (72%) patients' voices had improved subjectively; and the S/Z ratio exceeded 1.4 in just 6 patients (19%). Of these 6 patients, 4 exhibited laryngeal pathology on flexible nasoendoscopy. These 4 patients were followed up over 1 year, and 1 patient was ultimately offered a vocal cord medialization procedure. The S/Z ratio is 100% sensitive and 93% specific, with an accuracy of 93.75%, in diagnosing laryngeal pathology requiring ENT referral. Conclusions: 1. A period of laryngeal intubation carries signification risk of laryngeal dysfunction. Most, but not all, dysfunction resolves within 24 hours.2. Residual laryngeal pathology can be reliably and simply screened for by the use of the S/Z ratio. We recommend that patients with an S/Z ratio greater than 1.4 more than 24 hours after extubation require ENT referral for laryngoscopy. © 2010 Elsevier Inc.
dc.description.versionArticle
dc.identifier.citationJournal of Critical Care
dc.identifier.citation25
dc.identifier.citation3
dc.identifier.issn08839441
dc.identifier.other10.1016/j.jcrc.2009.11.009
dc.identifier.urihttp://hdl.handle.net/10019.1/14007
dc.subjectadolescent
dc.subjectadult
dc.subjectaged
dc.subjectarticle
dc.subjectclinical article
dc.subjectclinical assessment tool
dc.subjectclinical evaluation
dc.subjectdiagnostic accuracy
dc.subjectdiagnostic value
dc.subjectendoscopy
dc.subjectfemale
dc.subjectfunction test
dc.subjecthuman
dc.subjectinjury severity
dc.subjectintensive care unit
dc.subjectintubation
dc.subjectlarynx disorder
dc.subjectmale
dc.subjectpatient referral
dc.subjectrating scale
dc.subjects z ratio
dc.subjectscoring system
dc.subjectsensitivity and specificity
dc.subjectSouth Africa
dc.subjecttertiary health care
dc.subjecttreatment duration
dc.subjectvoice change
dc.subjectAdolescent
dc.subjectAdult
dc.subjectAged
dc.subjectAged, 80 and over
dc.subjectFemale
dc.subjectHumans
dc.subjectIntubation, Intratracheal
dc.subjectLaryngeal Diseases
dc.subjectLarynx
dc.subjectMale
dc.subjectMiddle Aged
dc.subjectPhonetics
dc.subjectProspective Studies
dc.subjectReference Values
dc.subjectReproducibility of Results
dc.subjectSensitivity and Specificity
dc.subjectSpeech Production Measurement
dc.subjectTime Factors
dc.subjectVoice Quality
dc.subjectYoung Adult
dc.titleThe S/Z ratio: A simple and reliable clinical method of evaluating laryngeal function in patients after intubation
dc.typeArticle
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