Wow, thanks for all the great advice! Last night I did a little research and found the info below in the merck manual. BTW, I tried the breathing in/out a paper bag and it worked great.
FYI, the following info was found at
Repeated involuntary spasm of the diaphragm, followed by sudden closure of the glottis, which checks the inflow of air and produces the characteristic sound.
Hiccups follow irritation of afferent or efferent nerves or of medullary centers that control the respiratory muscles, particularly the diaphragm. Afferent nerves may be stimulated by swallowing hot or irritating substances. High blood CO2 inhibits hiccups; low CO2 accentuates them. Hiccups are more common in men and often accompany diaphragmatic pleurisy, pneumonia, uremia, alcoholism, or abdominal surgery.
The cause of most prolonged or recurrent attacks can be determined, but the cause of other episodes may never become apparent. Causes include disorders of the stomach and esophagus, bowel diseases, pancreatitis, pregnancy, bladder irritation, hepatic metastases, and hepatitis. Thoracic and mediastinal lesions or surgery may be responsible. Posterior fossa tumors or infarcts may stimulate centers in the medulla oblongata.
Many simple measures may be tried: increasing PaCO2 and inhibiting diaphragmatic activity by a series of deep breath-holdings or by rebreathing deeply into a paper bag (Caution: Not a plastic bag, as it may cling to the nostrils). Vagal stimulation may work: drinking a glass of water rapidly, swallowing dry bread or crushed ice, inducing vomiting, or applying traction on the tongue or pressure on the eyeballs. Carotid sinus compression (massage) may be tried with proper precautions. Strong digital pressure may be applied over the phrenic nerves behind the sternoclavicular joints.
Other maneuvers include gastric lavage, galvanic stimulation of the phrenic nerve, and esophageal dilation with a small bougie. Gastric overdistension can be relieved by continuous suction. Inhalation of 5% CO2 in O2 is of value, particularly in postoperative patients. In diaphragmatic pleurisy, tight adhesive support of the lower chest may help. Drugs that control persistent hiccup include scopolamine, amphetamine, prochlorperazine, chlorpromazine, phenobarbital, and narcotics. Metoclopramide 10 mg po bid to qid appears to help some patients. Nevertheless, successful treatment with drugs is often elusive.
In troubling, refractory cases, the phrenic nerve may be blocked by small amounts of 0.5% procaine solution, with caution being taken to avoid respiratory depression and pneumothorax. Even bilateral phrenicotomy does not cure all cases.