A nurse is preparing to infuse 1 liter of 0.9% sodium chloride IV over 8 hr with a tubing set that delivers 15 gtts/mL. The nurse should set the manual IV infusion to deliver how many drops/min? Round the answer to the nearest whole number. Use a leading zero if it applies. Do not use a trailing zero.

Choice A Reason: This is incorrect because marijuana is a psychoactive substance that affects the central nervous system and can cause euphoria, relaxation, altered perception, and impaired memory. It does not cause tachycardia, hypertension, or vasoconstriction in pregnant women or their fetuses.

Choice B Reason: This is correct because cocaine is a stimulant substance that affects the cardiovascular system and can cause tachycardia, hypertension, vasoconstriction, arrhythmias, and ischemia in pregnant women or their fetuses. It can also increase the risk of placental abruption, preterm labor, intrauterine growth restriction, and fetal death.

Choice C Reason: This is incorrect because nicotine is a stimulant substance that affects the respiratory system and can cause bronchodilation, increased heart rate, and increased blood pressure in pregnant women or their fetuses. However, it does not cause vasoconstriction, but rather vasodilation.

Choice D Reason: This is incorrect because caffeine is a stimulant substance that affects the central nervous system and can cause alertness, insomnia, anxiety, and increased urine output in pregnant women or their fetuses. It does not cause tachycardia, hypertension, or vasoconstriction in moderate doses.

Choice E Reason: This is incorrect because heroin is an opioid substance that affects the central nervous system and can cause euphoria, sedation, analgesia, and respiratory depression in pregnant women or their fetuses. It does not cause tachycardia, hypertension, or vasoconstriction.

Choice A Reason: This is incorrect because ultrasound visualization of the fetus is a positive sign of pregnancy, not a probable sign. A positive sign of pregnancy is a direct and definitive evidence of the presence of a fetus, such as fetal movement felt by the examiner or fetal heart sounds heard by a Doppler device.

Choice B Reason: This is correct because softening of the cervix, also known as Goodell's sign, is a probable sign of pregnancy. A probable sign of pregnancy is a strong indication of pregnancy based on physical changes in the reproductive organs, such as enlargement of the uterus or changes in the shape and consistency of the cervix.

Choice C Reason: This is correct because a positive pregnancy test, which detects human chorionic gonadotropin (hCG) in urine or blood, is a probable sign of pregnancy. However, it is not a conclusive sign, as hCG can also be produced by other conditions such as ectopic pregnancy, molar pregnancy, or trophoblastic tumors.

Choice D Reason: This is correct because absence of menstruation, also known as amenorrhea, is a probable sign of pregnancy. It occurs when ovulation and menstruation cease due to hormonal changes during pregnancy. However, it is not a definitive sign, as amenorrhea can also be caused by other factors such as stress, illness, or hormonal imbalances.

Choice E Reason: This is correct because ballottement, which is a rebounding of the fetus against the examiner's fingers during a pelvic examination, is a probable sign of pregnancy. It can be felt around 16 to 20 weeks of gestation.

Choice F Reason: This is incorrect because auscultation of a fetal heart beat, which can be heard by a fetoscope around 18 to 20 weeks of gestation or by a Doppler device around 10 to 12 weeks of gestation, is a positive sign of pregnancy, not a probable sign.