MEDICAL INNOVATIONS
“Forced Inspiratory Suction and Swallow Tool’ (FISST):
A Novel Invention that Stops Hiccups Instantly By Ali Seifi, MD, FACP, FNCS, FCCM and Faraz Yousefian, DO
A
lthough hiccups have occurred in humans for ages, Thomas Lupton first scientifically characterized them in 1627.1 Lupton described hiccups as involuntary, synchronous, clonic spasms of the intercostal muscles and diaphragm, producing a sudden inspiration followed by an abrupt characteristic ‘Hic’ sound.1 However, it was not until 1970 that the pathophysiology was described in medical literature.2 Any pathology that affects the brain, diaphragm, thoracic or abdominal viscera can stimulate vagal or phrenic afferents and activate the hiccup centers in the midbrain, brainstem and proximal cervical cord. Examples of these triggers include distention or irritation of the stomach by a large meal, pepper or alcohol, over-excitement or central nervous system triggers such as stroke.1-4 While the prevalence of hiccup episodes occurring outside of the hospital setting would be difficult to quantify, it appears to be a ubiquitous problem. One published editorial from Forbes in 2019 noted that a search for hiccup cures was the third most frequently “Googled” health question.5 While most episodes are transient and resolve soon after onset, some may last longer. Persistent hiccups are defined as episodes exceeding 48 hours, and intractable hiccups are defined as lasting longer than one month, and can be due to organic pathologies and have been associated with complications.1-3 In fact, hiccups are repetitive, myoclonic contractions of the diaphragm followed by abrupt suction of air into the upper airway, triggered by a ‘reflex arc’ involving the phrenic and vagus nerves, respectively.3,4 Usually, a stimulant such as spicy food triggers the phrenic nerve adjacent to the stomach. Close anatomical location of the nucleus of the phrenic nerve with the vagus nerve triggers the vagus nerve, which innervates the larynx. Subsequently, it produces the well-known “Hic” sounds due to the abrupt suction of air into the airways. This battery of events will repeat as a reflex with various frequencies between four to 60 times per minute.4 Several home remedies to relieve transient hiccups have been proposed, such as breath holding, recycled breathing in a paper bag and drinking water from the far side of a glass.2 However, there was not a simple tool available to stop hiccups until recently. Considering the inconsistent performance and poor effectiveness of home remedies, there has been a need for a simple and effective hiccup terminating tool. Fol14
SAN ANTONIO MEDICINE • May 2022
lowing the same physiologic principles as home remedies, Dr. Seifi at the University of Texas Health Science Center at San Antonio designed and patented a straightforward, easily accessible and low-cost device, which is scientifically referred to as the “Forced Inspiratory Suction and Swallow Tool (FISST)” and branded as “HiccAway®.”7 The motivation to make such a device was based on a patient in the neuro intensive care unit who had a neurosurgical procedure. He developed hiccups after the operation and had hiccups for 24 hours, which was painful and disturbing and did not relieve with any of the known remedies nor with chlorpromazine. The patient asked us with a desperate tone while he had hiccups that he was pleased with his brain operation but so disturbed with the hiccups. This challenging moment was the start of the FISST invention. FISST is a specially designed straw with a pressure valve that subjects with hiccups, required to generate approximately negative 80 to 100 cmH2O pressure in adults (negative 30-50 cmH2O in children), to sip the water through it and swallow the water immediately.7,8 This tool involves the concordance activity of the phrenic and vagus nerves. First, it induces diaphragmatic contraction by negative inspiratory force with phrenic nerve activity. Subsequently, the activity of the vagus nerve closes the epiglottis during swallowing. FISST induces the simultaneous activity of the phrenic and vagus nerve and resets the nerves, thus stopping the hiccups. The performance of this tool has been studied on 674 subjects with hiccups, and the results have been published previously in JAMA Network in 2021 with more than 90% effectiveness compared to home remedies.8 FISST is a pen-like tool that users put in a cup of water and then drink the water through it. The device has three segments: (Figure 1) I. The mouthpiece on the upper end, which the user should hold in the mouth between the teeth to sip the water through it. II. The body, which is a straw-like conduit that carries the water from the lower end to the mouthpiece on the upper end. The body is approximately 15 cm long and has a variable internal diameter with an average one cm caliber. III. The lower-end cap, which is a unique pressure valve. The cap is detachable and can be set to one of the two various pressures: -100 cmH2O for adults and -50 cmH2O for children.
