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Panic Attacks and Lactated Ringer's Solution: Is There a Relationship?

Tsen, Lawrence C. MD; Datta, Sanjay MD, FFARCS

doi: 10.1213/00000539-199904000-00022
Obstetric Anesthesia: Case Report

Departments of Anesthesia, (Tsen, Datta) Harvard Medical School and (Datta) Brigham & Women's Hospital, Boston, Massachusetts.

Accepted for publication January 7, 1999.

Address correspondence and reprint requests to Lawrence C. Tsen, MD, Department of Anesthesia, Brigham & Women's Hospital, 75 Francis St., CWN-L1, Boston, MA 02115. Address e-mail to

Classified as a distinct entity with defined criteria [1], panic disorder affects 5% of the population and is diagnosed twice as frequently in women [2]. Pregnancy has no known effect on the disorder [3]. Although the neurobiological basis of panic disorder is unclear, sodium lactate has been used as a biologic marker and precipitant [4]. Because it contains lactate, lactated Ringer's solution has been avoided in patients with panic disorder [5]; we present this case to challenge that practice.

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Case Report

A 30-yr-old, term, primiparous parturient presented in active labor. The patient had no allergies, took no medications, and denied any past or current medical or obstetrical problems. Concerned about labor and delivery pain, the patient spontaneously reported her anxiety as 4 of 10 (0 = the absence of anxiety) and requested epidural analgesia. With placement of an IV line, 1000 mL of lactated Ringer's solution was rapidly infused, an epidural catheter was placed, and a continuous infusion of local anesthetic was started. Anxiety level, which did not change with fluid administration, decreased to 2 of 10 with analgesia onset. Ten minutes after epidural placement, the patient's arterial blood pressure decreased from 114/60 to 104/60 mm Hg, and 10 mg of IV ephedrine with 500 mL of lactated Ringer's solution was given. Noting the chronotropic change, the patient reported her anxiety as 4 of 10. No additional hemodynamic or pharmacologic interventions (aside from the oxytocin augmentation of labor) were made for the duration of the labor, and anxiety scores remained 2-4 of 10 at each 60- to 90-min check for analgesia. The patient delivered uneventfully, having received 5 L of lactated Ringer's solution on removal of her IV catheter. Fifty hours after delivery, the patient reported a sense of impending doom, extreme anxiety of 9 of 10, and a desire for lorazepam and nortriptyline. Questioned about these medications and her ability to score anxiety, the patient admitted to a panic disorder history, which she had kept from her obstetric and anesthetic care team for fear of being treated differently. Contact with the patient's psychiatrist confirmed her Diagnostic and Statistical Manual of Mental Disorders diagnosis [3]; with restoration of treatment with lorazepam and nortriptyline, the patient returned to her baseline anxiety state (3 of 10) for the remainder of her hospital course.

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Common in women during the childbearing years [6], panic attack frequency is unchanged and increased during the gravid and postpartum states, respectively [7,8]. The observation of increased lactate levels in anxiety neurosis patients [9] led to its use as a provocative drug [10]; however, analyses [11,12] of 13 recent studies concluded that sodium lactate infusions were neither sensitive nor specific for panic disorders. Nonetheless, the amount of lactate in lactated Ringer's solution would be unlikely to precipitate an attack. A 1-mM solution of sodium lactate contains 1002 mEq/L sodium lactate [13]; sodium lactate regimens (1-mM solution at 5 mL/kg given over 20 min) require at least 12 min [12] to reach a serum lactate threshold of 12-15 mM/L [11] necessary to precipitate a panic attack. Thus, a 70-kg person would require 210 mL (approximately 210 mEq) of sodium lactate to trigger an attack; lactated Ringer's solution (28 mEq/L lactate) would require 7.5 L to produce this amount. Yet this volume of lactated Ringer's solution, even if rapidly administered, would be unable to reach the panic threshold because of the dilutional forces of the crystalloid itself. Moreover, lactate undergoes rapid metabolism and clearance via hepatic and renal oxidation, gluconeogenesis, and excretion [14]. Even when large quantities of lactated Ringer's solution are given to patients in shock, lactate is readily metabolized [15].

The mechanism by which sodium lactate produces panic attacks focuses on the complexing of calcium [10], despite the absence of serum levels or symptoms of hypocalcemia [16]. In the seminal study of sodium lactate in panic disorder, when an arbitrary amount of calcium (0.2 mM) was added, a decrease in anxiety symptoms was recorded (from 34.3% to 17.1%) [17]. Lactated Ringer's solution contains 3 mEq/L calcium, which represents a 0.02-mM solution. Although this concentration of calcium is 10 times less than the 0.2 mM used in the previous study, it may serve to further diminish the theoretical relationship between lactated Ringer's solution and panic attacks. The simultaneous administration of different calcium concentrations in the lactate model of panic disorders has not been investigated.

Misdiagnosis is an unlikely explanation for why our patient did not experience a panic attack; the rigid diagnostic criteria used, her classic recurrence postpartum, and her resolution with treatment speak against this theory. More likely, the amount of lactate administered was insufficient to reach the minimal panic attack threshold. Consistent with our patient, should a panic attack occur, attention should be placed on psychological or emotional stressors [18], medications that mimic the symptoms or have a stronger potential relationship with panic disorders-i.e., chronotropic medications and oxytocin [19], respectively-the timing of the attack (postpartum), and other psychiatric disorders [20].

In summary, we present this case of a parturient with panic disorder that was not influenced by the use of lactated Ringer's solution. Although other fluid therapies may be readily available, we seriously question the avoidance of lactated Ringer's solution in patients with panic disorder.

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1. Diagnostic and statistical manual of mental disorders: DSM-IV. 4th ed. Washington, DC: American Psychiatric Association, 1994:394-5.
2. Villeponteaux VA, Lydiard RB, Laraia MT, et al. The effects of pregnancy on preexisting panic disorder. J Clin Psychiatry 1992;53:201-3.
3. Wisner KL, Peindl KS, Hanusa BH. Effects of childbearing on the natural history of panic disorder with comorbid mood disorder. J Affect Disord 1996;41:173-80.
4. Appleby IL, Klein DF, Sachar EJ, Levitt M. Biochemical indices of lactate-induced panic. In: Klein DF, Rabkin J, eds. Anxiety: new research and changing concepts. New York: Raven Press, 1981:411-22.
5. Datta S. The obstetric anesthesia handbook. 2nd ed. St. Louis, MO: Mosby-Year Book, 1995:254.
6. Robins LN, Helzer JE, Weissman MM. Lifetime prevalence of specific psychiatric disorders in three sites. Arch Gen Psychiatry 1984;41:949-58.
7. George GT, Ladenheim JA, Nutt DJ. Effect of pregnancy on panic attacks. Am J Psychiatry 1987;144:1078-9.
8. Cohen LS, Sichel DA, Dimmock JA, Rosenbaum JF. Postpartum course in women with preexisting panic disorder. J Clin Psychiatry 1994;55:289-92.
9. Cohen ME, Consalazio FC, Johnson RE. Blood lactate response during moderate exercise in neurocirculatory asthenia, anxiety neurosis, or effort syndrome. J Clin Invest 1947;26:339-42.
10. Pitts FN, McClure JN. Lactate metabolism in anxiety neurosis. N Engl J Med 1967;277:1329-36.
11. Margraf J, Ehlers A, Roth W. Sodium lactate infusions and panic attacks: a review and critique. Psychosom Med 1986;48:23-51.
12. Cowley DS. The diagnostic utility of lactate sensitivity in panic disorder. Arch Gen Psychiatry 1990;47:277-84.
13. Computerized Clinical Information System, Micromedex, Inc., Englewood CO (Edition 1998 Expires 3/98).
14. Narins RG, Krishna CG, Bresuler L, et al. The metabolic acidosies. In: Maxwell MH, Kleeman CR, Narins RG, eds. Clinical disorders of fluid and electrolyte metabolism. 4th ed. New York: McGraw-Hill, 1987:597.
15. Canizaro PC, Prager MD, Shires GT. The infusion of Ringer's lactate solution during shock. Am J Surg 1971;122:494-501.
16. Grosz HG, Farmer BB. Blood lactate in the development of anxiety symptoms: a critical evaluation of Pitts and McClure's hypothesis and experimental study. Arch Gen Psychiatry 1969;21:611-9.
17. Pitts FN, McClure JN. The biochemistry of anxiety. Sci Am 1969;220:69-75.
18. Klein DF. Pregnancy and panic disorder. J Clin Psychiatry 1994;44:293-4.
19. Benjamin J, Benjamin M. Panic disorder masquerading as preeclampsia. Eur J Obstet Gynecol Reprod Biol 1993;51:81-2.
20. Benjamin J, Benjamin M. Panic disorder and pregnancy [letter]. J Clin Psychiatry 1995;56:36.
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