For those living with cystic fibrosis (CF) from the 1960s to mid-1970s, nights called for fog. People with CF would tuck into bed under a plastic canopy filled with a medicated mist, accompanied by one or more whirring compressors nebulizing solution all night long. These “mist tents,” as the devices were known, were considered a mainstay of CF treatment—until, abruptly (and perhaps mercifully), they weren’t.
Mist tents were based on the principle of humidifying CF airways to thin mucus. They consisted of a mostly air-tight plastic sheet of the kind used for continuous oxygen therapy, suspended in a canopy over the user’s bed.
High-volume nebulizers were then fed into the space to aerosolize a sterile solution into mist that was supposed to be “so dense that the observer has difficulty seeing the patient in the tent.”  From first experiments with the process in the 1950s, their use ballooned in the 1960s on the advice of newly minted CF specialists. Most people with CF who had any degree of lung issues were advised to regularly sleep under these tents, and sometimes even stay in them for most of the day during periods of acute illness. Though some individual experiences were positive, such as that of 25-year-old Susan Carnal, who referred to her mist tent as “really the most important part of my life,” users generally found their use inconvenient, at best.  22-year-old Robbie Wimbs, speaking about his 1960s childhood from the vantage point of a post-mist tent world, recalled perhaps the most physical aspect of mist tent use: “you wake up soaked.”  Though, in theory, nebulizers producing a fine-enough mist shouldn’t “rain out” the patient, according to one of their most prominent physician advocates, firsthand user accounts rarely agree.  The morning routine of parents (usually mothers) drying off their children and bedsheets after mist tent nights was a regular part of many families’ CF routines. One speaker in 1970 noted that teenage girls in particular resisted[MR1] the mist tent because it ruined their hairdos. 
A high-powered compressor was needed to fill the tent with dense mist all night, or two of somewhat lesser power. Noise was thus omnipresent. As expressed by a reporter on the experience of 6-year-old Paul Brannen, in the child’s bedroom, “all night long, that machine goes hummmmmmmmmmmmm.”  This noise was hardly conducive to anyone’s sleep. For some, like 2-year-old Bruce Frankford, the solution was to flat-out house the compressor in its own unit outside the bedroom window. 
Left: Illustration from a 1968 patent for an ultrasonic nebulizer for use with a mist tent (Robert L. Weaver and Frank D. Myrice, Ultrasonic nebulizer, United States US3593712A, filed July 1, 1968, and issued July 20, 1971) Right: A similar compressor apparatus attached to an oxygen tent. (MCKESSON APPLIANCE CO., Oxygen machine & tent, circa 1950–1960, artifact no. 1972.0266.001, Ingenium – Canada’s Museums of Science and Innovation)
Probably unsurprisingly, efforts to introduce mist tent therapy to adults not previously using them were often unsuccessful. For children, with less say in the matter, compliance was encouraged via the entry of favourite toys into the tent—though not all could fit. Paul Brannen, for instance, recounted this story to the reporter: “Last night I wanted to bring my teddy bear to bed with me but my mom said he wouldn’t fit under the tent. He’s so big. His name is Bozo and he’s bigger’n me. He doesn’t need a tent my mama said so he slept on the floor.”  A space analogy could help, as it did for one mother in the 1970s who said the mist tent was: “a space ship [her son] was going into, and he used to play in it and switch it on himself. When the man took it away he asked would he bring it back. He thought it was his and a toy.”  Children themselves might be the source of such playful conceptions. The sibling of a boy with CF recalled feeling his brother “was the lucky one because he got to sleep with the mist tent over his bed. He had his own fort and I wanted in the club.” Sometimes the two would undertake “an adventure underneath his plastic water world.” 
For other children, however, the experience was more daunting. One poor eight-year-old, facing her new mist tent “thought it was a cellophane bag and [her mother] had her scared of them and she just sat in the tent and shook and she was terrified. ‘I’m going to die. I’m going to die,’ she said.”  Similarly, Debbie Pitts recalled a childhood where “each night I had to crawl into bed and have this big, plastic type of tent pulled down over my bed and tucked into the sides and bottom of the mattress (my own silent, hated, plastic world).” 
Users of mist tents, whether occupants or their parents, also had plenty to grapple with materially. According to recommendations, tents were supposed to be disassembled, washed with soap and water, sanitized with alcohol or vinegar, and air-dried on a daily basis. The plastic tents themselves were not inexpensive, requiring care of tears and rips via scotch tape and patches. However, even when this cleaning regime was strictly adhered to—apparently somewhat rare—the materials were easily contaminated with bacteria, especially the noxious Pseudomonas aeruginosa. 
It was this negative finding in studies from the 1970s, along with little empirical evidence for positive benefits, that sent the mist tent into rapid disfavour among medical professionals. Patients and families, many disliking most or all aspects of the process, put up little protest. “It was easy to push people off the mist tent bench,” recalled CF specialist Dr. Robert Stern. “It fit into their lifestyle.”  One British doctor recalled his own abandonment of the mist tent in the early 1970s as prompted by an engaged patient asking if she should bring her mist tent on her honeymoon. Between the recently published negative study results and awareness of the treatment’s psychological impact, he concluded “it’s time to stop the mist tent.”  Mist tent usage was discontinued in Canadian clinics in the 1970s, and most US clinics by the early 1980s. People with CF born after this period, like myself, were fortunately spared the experience of prescribed sleeps in fog. I think I may speak for many of us when I say—thank goodness!
 LeRoy W. Matthews et al., “A Therapeutic Regimen for Patients with Cystic Fibrosis,” The Journal of Pediatrics 65, no. 4 (October 1, 1964): 561.
 Susan Carnal, “Susan Lives Daily With Problems of Cystic Fibrosis,” The Gazette, June 22, 1975.
 Bob Brehl, “Robbie a Symbol of Hope for Many,” Toronto Star, July 3, 1983.
 Matthews, “A Therapeutic Regimen,” 560.
 Susan Ruttan, “Burden of Therapy on Parents,” The Kingston Whig-Standard, March 4, 1970.
 Joe Torchio, “He’s Just a Kid,” The Palm Beach Post, December 31, 1972.
 “OKmulgeeans Buy Nebulizer for Tot,” Okmulgee Daily Times, February 2, 1960.
 Torchio, “Just a Kid.”
 Lindy Burton, The Family Life of Sick Children: A Study of Families Coping with Chronic Childhood Disease (London: Routledge, 1975), 88-89.
 D. Patrick Williams, “The Well Sibling’s Perspective,” in Bryan Lask, Denise B. Angst, and Myra Bluebond-Langner, eds., Psychosocial Aspects of Cystic Fibrosis (London : New York: Arnold ; Oxford University Press, 2001), 74.
 Burton, The Family Life of Sick Children, 95.
 Quoted in Michelle Lynne Labonte, “The Mist Tent: An Analysis of Therapeutic Change in the History of Cystic Fibrosis Care,” Bulletin of the History of Medicine 92, no. 4 (2018): 657.
 E. K. Motoyama, L. E. Gibson, and C. J. Zigas, “Evaluation of Mist Tent Therapy in Cystic Fibrosis Using Maximum Expiratory Flow Curve,” in Cystic Fibrosis (New York: MSS Information Corp., 1973).
 Quoted in Labonte, “The Mist Tent,” 662.
 D. A Christie, E. M Tansey, and Wellcome Trust Centre for the History of Medicine at UCL, eds., Wellcome Witnesses to Twentieth Century Medicine. the Transcript of a Witness Seminar Held by the Wellcome Trust Centre for the History of Medicine at UCL, London, on 11 June 2002 Vol. 20, Vol. 20, (London: Wellcome Trust Centre for the History of Medicine, 2004), 24.
For more detailed analysis of the ascendancy and decline of the mist tent, see Michelle Lynne Labonte’s excellent article: “The Mist Tent: An Analysis of Therapeutic Change in the History of Cystic Fibrosis Care,” Bulletin of the History of Medicine 92, no. 4 (2018): 634–63.