IN THE

SUPREME COURT OF THE STATE OF ARIZONA

ANTOINETTE WINDHURST, A SINGLE/WIDOWED WOMAN, ON BEHALF OF 

HERSELF, AND AS A PERSONAL REPRESENTATIVE OF THE ESTATE OF HER 

DECEASED HUSBAND, DAVID WINDHURST,

Plaintiff/Appellant,

v.

ARIZONA DEPARTMENT OF CORRECTIONS, A GOVERNMENTAL ENTITY; RYAN 

THORNELL, IN HIS INDIVIDUAL CAPACITY AS THE DIRECTOR 

OF ARIZONA DEPARTMENT OF CORRECTIONS;STATE OF ARIZONA, A 

GOVERNMENTAL ENTITY; CORIZON HEALTH, INC., A BUSINESS 

DOMICILED IN ARIZONA,

Defendants/Appellees. 

No. CV-21-0288-PR

Filed October 11, 2023

Appeal from the Superior Court in Pima County

The Honorable Brenden J. Griffin, Judge

No. C20175978

REVERSED AND REMANDED

Opinion of the Court of Appeals, Division Two

252 Ariz. 240 (2021)

VACATED

COUNSEL:

Rita J. Bustos (argued), Anthony J. Fernandez, Dustin A. Christner, Alyssa 

R. Illsley, Quintairos, Prieto, Wood & Boyer, P.A., Scottsdale, Attorneys for 

Corizon Health, Inc., Arizona Department of Corrections, Ryan Thornell, 

and the State of Arizona
ANTOINETTE WINDHURST V.ADOC, ET AL.

Opinion of the Court

2

Nathan S. Rothschild, Bernardo M. Velasco (argued), Mesch Clark 

Rothschild, Tucson; and Michael J. Crawford, Crawford Law, PLLC, 

Tucson, Attorneys for Antoinette Windhurst

Eileen Dennis GilBride, Jones, Skelton & Hochuli P.L.C., Phoenix, Attorney 

for Amici Curiae Banner Health, Dignity Health, HonorHealth, Mutual 

Insurance Company of Arizona, and Phoenix Children’s Hospital

David L. Abney, Ahwatukee Legal Office, P.C., Phoenix; and Daniel 

Rubinov, RAJ Law PLLC, Phoenix, Attorneys for Amicus Curiae Arizona

Association for Justice/Arizona Trial Lawyers Association

JUSTICE BEENE authored the Opinion of the Court, in which CHIEF 

JUSTICE BRUTINEL, VICE CHIEF JUSTICE TIMMER, and JUSTICES 

BOLICK, and LOPEZ joined.*

JUSTICE BEENE, Opinion of the Court:

¶1 A plaintiff who brings a medical malpractice action must 

prove that a medical institution or individual provider fell below the 

applicable standard of care. See A.R.S. §§ 12-563, -561(1)(a); Seisinger v. 

Siebel, 220 Ariz. 85, 94 ¶ 32 (2009). Expert medical testimony is necessary to 

establish the applicable standard of care, and experts testifying to the 

standard must satisfy the requirements of Arizona Rule of Evidence 702 

and A.R.S. § 12-2604. Seisinger, 220 Ariz. at 94–95 ¶¶ 33, 39–40.

¶2 In this case, we apply these legal principles to the following 

issues: (1) whether § 12-2604 applies to medical institutions, and under 

what circumstances; (2) whether the court of appeals erred in concluding 

that the jury could infer causation; and (3) whether a registered nurse may 

testify regarding the cause of death in a medical malpractice case. For the 

∗ Justices William G. Montgomery and Kathryn H. King recused themselves

from this matter.
ANTOINETTE WINDHURST V.ADOC, ET AL.

Opinion of the Court

3

reasons set forth in this opinion, we hold that § 12-2604’s requirements do 

not apply to claims against medical institutions not based on vicarious 

liability; Windhurst presented appropriate expert causation testimony and, 

therefore, the jury did not have to infer causation; and a registered nurse 

may testify about the cause of death in a medical malpractice case if

Rule 702’s requirements are met.

BACKGROUND

¶3 In December 2015, David Windhurst (“David”) was 

incarcerated at the Arizona State Prison in Florence. David was paraplegic 

and had various chronic medical issues, including diabetes mellitus, 

hypertension, obesity, kidney disease, and injuries to his back and buttocks. 

Because of his medical conditions, David was placed in the prison’s 

infirmary, where Arizona Department of Corrections (“ADOC”) provided 

his health care through its contractor Corizon Healthcare Inc. (“Corizon”). 

When Corizon began caring for David, his medical conditions were stable.

¶4 In February 2016, David went into septic shock and was 

transferred to a hospital where he remained for over a month. After his 

release from the hospital, David was taken to a state prison in Tucson where 

he was housed in the infirmary under Corizon’s care. In November 2016, 

David was admitted again to the hospital in septic shock, and on December 

25, he died due to infectious complications of diabetes mellitus.

¶5 David’s widow, Antoinette Windhurst (“Windhurst”) filed a 

wrongful death action against Corizon, ADOC and its director, and the 

State of Arizona, claiming, among other things, medical malpractice. 

Windhurst alleged both institutional negligence by Corizon and vicarious 

liability based on the negligence of its medical personnel. In support of her 

claims, Windhurst provided David’s medical records, as well as deposition 

testimony and reports from three expert witnesses: Zachary Rosner, a 

medical doctor; Tara Hood, a nurse practitioner; and Denise Panosky, a 

registered nurse. At the time, Dr. Rosner was the chief of medical services 

for the New York City jail system; Hood had worked for over ten years as

a nurse practitioner in a correctional facility; and Panosky had over fourteen 
ANTOINETTE WINDHURST V.ADOC, ET AL.

Opinion of the Court

4

years of experience as a professor, teaching students about nursing in a 

correctional facility setting.

¶6 Corizon moved for summary judgment, arguing that there 

was no evidence that it violated the standard of care or caused David’s 

death. Specifically, Corizon asserted that Windhurst failed to provide

standard-of-care opinions regarding specific providers. It also claimed that 

Dr. Rosner only alleged that “clinicians” fell below the standard of care and 

did not specify which particular clinician fell below the standard of care or 

how such clinician’s care caused David’s death. Corizon also argued that, 

as a nurse, Panosky was not qualified to establish causation based on her 

professional position.

¶7 The trial court granted Corizon’s motion on the medical 

negligence claim because it did not “see the medical expert testimony that 

links everything up.” The court invited Windhurst to file a motion for 

reconsideration that “tied together . . . either a specific doctor or doctors, a 

specific nurse or nurses; what standard of care applied and that that 

particular provider or category of providers breached; how they breached 

it; [and] what corresponding expert says that.”

¶8 Windhurst filed a motion for reconsideration. In her motion, 

Windhurst pointed to evidence that Corizon failed to treat David’s wounds 

and properly care for his catheter, failed to follow specialist 

recommendations, and failed to diagnose and treat David’s sepsis. She also 

cited testimony from the record where Dr. Rosner, Hood, and Panosky gave 

causation testimony. The trial court denied the motion, however, finding 

that Windhurst still did not “connect the dots.” Windhurst appealed.

¶9 The court of appeals vacated the trial court’s grant of

summary judgment on the medical negligence claim. Windhurst v. Ariz. 

Dep’t of Corrs., 252 Ariz. 240, 249 ¶ 40 (App. 2021). After reviewing the 

expert opinions of Dr. Rosner, Hood, and Panosky, the court concluded that 

these witnesses gave sufficient testimony about the institutional and 

individual standards of care for Corizon and its personnel, respectively. Id. 

at 245 ¶ 19, 246 ¶¶ 23–27. Additionally, the court of appeals held that 

Windhurst’s experts gave sufficient causation testimony. Id. at 246 ¶ 27, 247
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Opinion of the Court

5

¶ 30, 249 ¶ 37. Finally, relying on Rasor v. Northwest Hospital LLC (Rasor I), 

244 Ariz. 423 (App. 2018), the court concluded that Panosky met the expert 

qualification standards of Rule 702 and could testify regarding the cause of 

death. Windhurst, 252 Ariz. at 248–49 ¶ 36.

¶10 We granted review because this case presents recurring issues 

of statewide concern. We have jurisdiction under article 6, section 5(3) of 

the Arizona Constitution.

DISCUSSION

¶11 We review the entry of summary judgment de novo, viewing 

the facts in the light most favorable to Windhurst as the nonmoving party. 

See S. Point Energy Ctr. LLC v. Ariz. Dep’t of Revenue, 253 Ariz. 30, 33 ¶ 10 

(2022). Similarly, we review questions of statutory interpretation de novo. 

State v. Ariz. Bd. of Regents, 253 Ariz. 6, 12 ¶ 22 (2022).

I.

¶12 Windhurst’s wrongful death action alleged both institutional 

negligence by Corizon and vicarious liability based on the negligence of 

Corizon’s medical personnel.1 Here, we must determine whether 

§ 12-2604’s standard of care requirements for an expert witness in a medical 

malpractice case apply to an institutional liability claim. Answering this 

question requires us to interpret § 12-2604.

¶13 “Our task in statutory construction is to effectuate the text if 

it is clear and unambiguous.” BSI Holdings, LLC v. Ariz. Dep’t of Transp., 244 

Ariz. 17, 19 ¶ 9 (2018). “In doing so, we interpret statutory language in view 

of the entire text, considering the context and related statutes on the same 

1 Corizon insists that Windhurst failed to specifically plead institutional

negligence. Though Windhurst did not use the exact phrase “institutional 

negligence” in her complaint, she alleges that Corizon breached the 

applicable standard of care by failing to adhere to state law, as well as its 

own policies and procedures. This allegation satisfies Arizona’s pleading 

standards by indicating the type of litigation involved and putting Corizon 

on notice. See Cullen v. Auto-Owners Ins. Co., 218 Ariz. 417, 419 ¶ 6 (2008).
ANTOINETTE WINDHURST V.ADOC, ET AL.

Opinion of the Court

6

subject,” Molera v. Hobbs, 250 Ariz. 13, 24 ¶ 34 (2020) (cleaned up) (quoting 

Ariz. Chapter of the Associated Gen. Contractors of Am. v. City of Phoenix., 247 

Ariz. 45, 47 ¶ 7 (2019)), giving the words “their ordinary meaning unless it 

appears from the context or otherwise that a different meaning is intended.” 

State ex rel. Brnovich v. Maricopa Cnty. Cmty. Coll. Dist. Bd., 243 Ariz. 539, 541 

¶ 7 (2018) (citation omitted).

¶14 In all negligence actions, including medical malpractice, “the 

plaintiff must prove the existence of a duty, a breach of that duty, causation, 

and damages.” Seisinger, 220 Ariz. at 94 ¶ 32. For medical malpractice 

specifically, a plaintiff must prove that (1) “[t]he health care provider failed 

to exercise that degree of care, skill and learning expected of a reasonable, 

prudent health care provider in the profession or class to which he belongs 

within the state acting in the same or similar circumstances,” and (2) “[s]uch 

failure was a proximate cause of the injury.” A.R.S. § 12-563; see also Baker 

v. Univ. Physicians Healthcare, 231 Ariz. 379, 384 ¶ 12 (2013) (“In medical 

malpractice cases, plaintiffs must show that a health care provider breached 

the appropriate standard of care and the breach resulted in injury.”). 

“Unless malpractice is grossly apparent, the standard of care must be 

established by expert medical testimony.” Rasor v. Nw. Hosp., LLC (Rasor 

II), 243 Ariz. 160, 163 ¶ 12 (2017).

¶15 Section 12-2604(A) provides additional expert witness 

qualifications that are required to testify in a medical malpractice action:

A. In an action alleging medical malpractice, a person shall 

not give expert testimony on the appropriate standard of 

practice or care unless the person is licensed as a health 

professional in this state or another state and the person meets 

the following criteria:

1. If the party against whom or on whose behalf the 

testimony is offered is or claims to be a specialist, specializes 

at the time of the occurrence that is the basis for the action in 

the same specialty or claimed specialty as the party against 

whom or on whose behalf the testimony is offered. If the party 

against whom or on whose behalf the testimony is offered is 
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Opinion of the Court

7

or claims to be a specialist who is board certified, the expert 

witness shall be a specialist who is board certified in that

specialty or claimed specialty.

2. During the year immediately preceding the occurrence 

giving rise to the lawsuit, devoted a majority of the person’s 

professional time to either or both of the following:

(a) The active clinical practice of the same health profession 

as the defendant and, if the defendant is or claims to be a 

specialist, in the same specialty or claimed specialty.

(b) The instruction of students in an accredited health 

professional school or accredited residency or clinical 

research program in the same health profession as the 

defendant and, if the defendant is or claims to be a specialist,

in an accredited health professional school or accredited 

residency or clinical research program in the same specialty

or claimed specialty.

3. If the defendant is a general practitioner, the witness has 

devoted a majority of the witness’s professional time in the 

year preceding the occurrence giving rise to the lawsuit to 

either or both of the following:

(a) Active clinical practice as a general practitioner.

(b) Instruction of students in an accredited health 

professional school or accredited residency or clinical 

research program in the same health profession as the

defendant.

¶16 Under subsection (A), the qualifications of a standard of care 

witness are dependent on what “health profession” the defendant practices 

and whether the defendant is a “specialist” or “general practitioner.” 

§ 12-2604(A)(1)–(3). Because the defendant in this case, Corizon, is not 

engaged in a “health profession” and is neither a “specialist” nor “general 

practitioner,” § 12-2604 does not apply. Though these terms are not defined 

in Title 12, their use in § 12-2604 and their definitions in related statutes 

support this conclusion.
ANTOINETTE WINDHURST V.ADOC, ET AL.

Opinion of the Court

8

¶17 Section 32-3201 defines “[h]ealth professional” as “a person

who is certified or licensed” to work as a member of certain professions 

listed in Titles 32 and 36. 2 A.R.S. § 32-3201(2) (emphasis added). Under this 

statute, doctors, nurse practitioners, and nurses are included as health 

professionals. Though statutory references to “persons” generally include 

both legal entities and natural persons, see A.R.S. § 1-215(29), § 32-3201(2) 

only refers to natural persons and we decline to apply a statute governing 

individual licenses to a legal entity. See generally Fleming v. State Dep’t of 

Pub. Safety, 237 Ariz. 414, 417 ¶ 12 (2015) (refusing to apply a meaning that 

“leads to impossible or absurd results”) (quoting Orca Commc’ns Unlimited, 

LLC v. Noder, 236 Ariz. 180, 182 ¶ 9 (2014)).

¶18 Section 12-2604 also distinguishes between “health 

professional[s]” and institutional entities. Section 12-2604(B) expressly 

applies to “health care institution[s].” It reads, in relevant part: “If the 

defendant is a health care institution that employs a health professional

against whom or on whose behalf the testimony is offered, the provisions 

of subsection A apply as if the health professional were the party or 

defendant.” § 12-2604(B). This section applies when an institution is a 

defendant in a negligence action based on the actions of a health 

professional it employs. If an institution could be a “health professional,” 

§ 12-2604(B) would be superfluous. It therefore follows that, under 

§ 12-2604, “health professional[s]” must be individuals, as opposed to 

institutions. See generally Nicaise v. Sundaram, 245 Ariz. 566, 568 ¶ 11 (2018)

(disapproving of an interpretation that renders a provision superfluous).

¶19 Similarly, “[s]pecialist” is defined as an individual. See A.R.S. 

§ 32-1800(21) (defining specialist as a physician who has completed 

additional training or is certified by a specialty board). Although “general 

practitioner” is not defined in Title 32 or 36, absent statutory definitions,

courts generally give words their ordinary meaning and may look to 

dictionary definitions. Chaparro v. Shinn, 248 Ariz. 138, 141 ¶ 14 (2020). The 

Oxford Advanced Learner’s Dictionary defines “general practitioner” as “a 

doctor who is trained in general medicine and who treats patients in a local 

2 Section 32-3201(2) references certain articles in Title 36, but those articles 

are not related to health care institutions like Corizon.
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Opinion of the Court

9

community rather than at a hospital.” General Practitioner, Oxford 

Advanced Learner’s Dictionary, https://www.oxfordlearnersdictionaries.

com/us/definition/english/general-practitioner?q=general+practitioner

(last visited Sept. 13, 2023). The Merriam-Webster Dictionary defines 

“general practitioner” as “a physician or veterinarian whose practice is not 

limited to a specialty.” General Practitioner, Merriam-Webster,

https://www.merriam-webster.com/dictionary/general%20practitioner

(last visited Sept. 13, 2023). Both definitions refer to a general practitioner 

as an individual person, rather than a group or a collective. Thus, it follows 

that, like the terms “health professional” and “specialist,” the term “general 

practitioner” is defined as an individual engaged in the practice of medicine.

¶20 After considering § 12-2604(A)(1)–(3), its context, and related 

statutes on the subject, we conclude that an institution cannot be a licensed 

health professional because an institution cannot be a natural person. See

§ 32-3201(2). And thus, in a suit against a medical institution, it would be 

impossible for a plaintiff to produce an expert in the “same health 

profession as the defendant.” See § 12-2604(A). Similarly, it would be 

impossible for a plaintiff to present an expert under § 12-2604(A)’s 

requirements because an institution, by definition, cannot be a “specialist” 

or “general practitioner.” Accordingly, § 12-2604(A) is inapplicable to 

claims based on a theory of institutional liability.

¶21 In this case, Windhurst alleged claims against Corizon for 

institutional negligence and vicarious liability for the negligent conduct of 

its employees. See Kopp v. Physician Grp. of Ariz., Inc., 244 Ariz. 439, 441–42

¶¶ 9–12 (2018) (explaining that institutional claims can be proven either by 

showing an independent duty to the patient or through vicarious liability 

of the institution’s employees). As this Court has previously stated, a health 

care institution has a standard of care independent from the medical 

professionals it employs. See Thompson v. Sun City Cmty. Hosp., Inc., 141 

Ariz. 597, 604 (1984) (noting that hospitals and physicians have distinct 

standards of care). Because § 12-2604(A) is not applicable to a claim for 

institutional negligence, an expert on this issue need only satisfy Rule 702, 

which requires that the witness have “specialized knowledge [that] will 

help the trier of fact to understand the evidence or to determine a fact in 

issue.” Ariz. R. Evid. 702.
ANTOINETTE WINDHURST V.ADOC, ET AL.

Opinion of the Court

10

¶22 We conclude that the trial court erred in granting partial 

summary judgment based on its inability to compare the qualifications of 

the Corizon employees that provided medical care with the qualifications 

of Windhurst’s corresponding experts. Windhurst provided proper expert 

standard-of-care testimony for each class of medical provider and these

experts presented appropriate testimony regarding how Corizon’s medical 

providers’ actions, or inactions, contributed to David’s injuries. See Part 

II(B)–(D) ¶¶ 34–45. Testimony of these failures supported Windhurst’s 

institutional negligence claim.

¶23 Windhurst also provided competent expert evidence

regarding the standard of care that applied to Corizon as an institution. 

Regarding this claim, Dr. Rosner’s general reference to clinicians provided

the requisite specificity to establish that Corizon had fallen below its 

standard of care by failing to remove obstacles to the clinicians’ ability to 

perform their work. See Part II(A) ¶¶ 28–33. Moreover, evidence that an 

entire class of providers failed to exercise appropriate care suggests an 

institutional failure. Therefore, we conclude that, when it is unclear which 

provider breached the standard of care, an expert on institutional standards 

of care may address an alleged breach by establishing that a class of 

providers failed to exercise appropriate care.

II.

¶24 Next, we address whether the court of appeals erred in 

concluding that the jury could infer causation in contravention of Sampson 

v. Surgery Center of Peoria, LLC, 251 Ariz. 308 (2021).

¶25 Causation is a legal requirement for any medical malpractice 

claim. See Evans v. Bernhard, 23 Ariz. App. 413, 415 (1975). “Causation is 

generally a question of fact for the jury unless reasonable persons could not 

conclude that a plaintiff had proved this element.” Barrett v. Harris, 207 

Ariz. 374, 378 ¶ 12 (App. 2004). It requires the plaintiff to show “a natural 

and continuous sequence of events stemming from the defendant’s act or 

omission, unbroken by any efficient intervening cause, that produce[d] an 

injury, in whole or in part, and without which the injury would not have 
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Opinion of the Court

11

occurred.” Sampson, 251 Ariz. at 311 ¶ 15 (quoting Barrett, 207 Ariz. at 378 

¶ 11). Furthermore, the injury must be “probable, not merely speculative.” 

Id.

¶26 In most medical malpractice cases, a plaintiff must establish 

causation using expert testimony. Id. ¶ 13. The narrow exception is when 

the malpractice is so “readily apparent” that a jury can infer causation. Id.

(quoting Rasor II, 243 Ariz. at 166 ¶ 32). When the standard of care or cause 

of death is disputed on a matter requiring medical knowledge, causation 

by inference should be limited to those situations where causation is 

“grossly apparent.” Id. at 312 ¶ 19 (quoting Rasor II, 243 Ariz. at 163 ¶ 12).

¶27 Here, Corizon argues that because the cause of death is 

disputed and not readily apparent, expert causation testimony is required

to explain how the alleged breaches by the institution and its employees 

caused or contributed to David’s death.

A. Medical Institution

¶28 As previously indicated, Windhurst alleged institutional 

negligence by Corizon and vicarious liability based on the negligence of its 

personnel. In support of this claim, Dr. Rosner stated in his report that it 

was appropriate to apply the standards of care set by the Centers for 

Medicine and Medicaid Services (“CMS”) for long-term care facilities to a 

prison infirmary. Dr. Rosner cited the CMS standard of care for the 

availability of emergency services which states that a “facility must provide 

or arrange for the provision of physician services 24 hours a day, in case of 

an emergency.” 42 C.F.R. § 483.30(d). Rosner stated that this standard was 

“clearly not met” because David became “gravely ill” and “nurses 

concerned for his well-being were unable to promptly contact a higher level 

of Clinician for management decisions” and “[w]hen the physician was 

finally contacted there was not prompt in person evaluation that resulted.” 

Dr. Rosner further stated:

When a system is structured in such a way that an infirmary 

setting does not have a physician working in an infirmary 

setting around the clock it must have accessible physician 
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12

oversite [sic] and be prepared to rapidly escalate care for 

unstable patients. When the on-call physician is both unable 

to come in to evaluate a decompensating patient while also 

not willing to remotely advise transfer to an emergency room 

where physician services are available around the clock, that 

system cannot be said to have provided or “arrange[d]” for 

the provision of physician services 24 hours a day.

¶29 Dr. Rosner provided additional expert causation testimony 

regarding this claim when he expressed that “the prison was unable to 

come close to approaching the standard of care that Mr. Windhurst 

required” and that Corizon’s “inability to provide this level of care should 

have been easily recognizable . . . and failure to acknowledge and act on 

this led to Mr. Windhurst’s decompensation, development of severe 

complications of an otherwise treatable infection, and ultimately his 

premature death.” Dr. Rosner’s statements satisfied the requirement for 

expert causation testimony because he testified that Corizon and its 

employees breached the emergency-services-availability standard of care 

and caused David’s death.

¶30 Dr. Rosner also discussed another institutional standard of 

care he believed Corizon breached: proper maintenance of medical records. 

In his report, Dr. Rosner stated that a “medical record is the commonly 

accepted location for communicating clinical information from a variety of 

sources.” He asserted that the standard of maintaining medical records is 

to “directly populat[e] the medical record in a way which could be assessed 

by multiple different care givers.” He added that “[s]uch direct population 

of the medical record with lab results is standard for current electronic 

health records and critical since easy access to review a patients [sic] past 

lab results is a critical component of having a complete picture of the patient 

being provided care.”

¶31 According to Dr. Rosner, however, Corizon breached this 

standard by improperly maintaining medical records. In his report, Dr. 

Rosner stated that “lab results were routinely reviewed on paper or via 

email” by Corizon’s clinicians. But he also noted that a Corizon provider

“communicat[ed] only via word-of-mouth sign-out with nurses and not 
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Opinion of the Court

13

reviewing the chart for documentation of patient progress in some 

instances, and in others not receiving lab results in the electronic record,”

and often, results or “concerning findings” would not reach higher level 

clinicians. In discussing this breach, Dr. Rosner asserted that “[t]his

significant structural flaw was particularly contributory in this case” 

because it delayed obtaining the results of a lab report “which . . . under 

normal standards would have warranted a change in [care] management.”

¶32 Dr. Rosner also stated that Corizon’s clinicians “appear to 

have been working in an environment and under obligations that 

systematically limited their individual ability to provide a level of care that 

Mr. Windhurst required.” This included “poor electronic and manual 

tracking systems critical to providing adequate care to a patient with Mr. 

Windhurst’s medical needs.” Thus, Dr. Rosner concluded that the “actions 

and inactions” by Corizon providers represented a breach of the standard 

of care that “more probably than not caused or contributed to David 

Windhurst’s eventual death.”

¶33 Windhurst identified the standard of care regarding the 

maintenance of medical records, discussed how the standard was breached,

and sufficiently specified how the breach caused David’s death. 

Accordingly, Windhurst’s competent expert testimony would prevent the 

jury from having to infer causation on the institutional negligence claim.

B. Nurse Practitioners

¶34 Next, we examine whether the jury would have to infer that 

the alleged negligent conduct of Corizon’s nurse practitioners caused 

David’s death.

¶35 Windhurst’s expert, Hood, stated that several nurse 

practitioners who treated David breached multiple standards of care. One 

standard cited by Hood required nurse practitioners to recognize the limits 

of their “knowledge and experience by consulting with or referring patients 

to other appropriate health care professionals if a situation or condition 

occurs that is beyond the[ir] knowledge and experience . . . or if the referral 
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Opinion of the Court

14

will protect the health and welfare of the patient.” A.R.S. 

§ 32-1601(23)(d)(vi).

¶36 In her report, Hood documented numerous breaches of this 

standard. Regarding one such breach, Hood noted that in November 2016, 

Castillo, a Corizon nurse practitioner, failed to realize David’s deteriorating 

condition and subsequently did not raise any concerns to an attending 

physician, despite a serious decline in David’s health. Hood also stated that 

another Corizon nurse practitioner, Ross, breached the standard of care 

regarding several aspects of David’s case including prescribing a 

contraindicated medication for David, who suffered from chronic kidney 

disease. Despite repeated encounters with David, Hood noted that Ross 

prolonged David’s pain and suffering by failing to consult with a physician 

or order testing regarding his skin condition. Hood then concluded that the 

“actions and inactions by nurse practitioners . . . working with or for 

Corizon Health, represent breaches of the applicable standards of care that 

more probably than not caused or contributed to David Windhurst’s 

death.”

¶37 Hood’s expert causation testimony corresponds with the 

causation opinion reached by Dr. Rosner. After reviewing the health care 

services provided by Corizon, Dr. Rosner opined that the “actions and 

inactions by Clinicians . . . working with or for Corizon Health, represented 

breaches of the applicable community standards of care that more probably 

than not caused or contributed to David’s . . . eventual death.”

¶38 Windhurst’s experts identified the appropriate standards of 

care for nurse practitioners, discussed how these standards were breached,

and specified how these breaches caused David’s death. Thus, the jury will 

not have to infer causation.

C. Registered Nurses

¶39 Finally, we consider whether the jury would have to infer

causation regarding the alleged negligent conduct of Corizon’s registered 

nurses.
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Opinion of the Court

15

¶40 In her report, Windhurst’s nursing expert, Panosky, identified

several standards of care that were breached by Corizon’s nurses. One 

standard requires nurses to “intervene on behalf of a client when problems 

are identified.” Ariz. Admin. Code R4-19-402(C)(4)(e) (cleaned up). 

Panosky listed numerous breaches of this standard. She stated that 

Corizon’s nurses should have escalated care when David’s urine output fell 

below a certain amount for two consecutive nights in November 2016. She

also noted that during this time, Hughes, a Corizon nurse, reported that 

David had no appetite, consistently had critically low blood sugars, and 

had gray-tinted skin. Despite this, Hughes did not notify a higher-level 

provider for over forty-eight hours. Panosky noted that another breach of 

this standard occurred on November 18, 2016, the day that David was 

admitted to the hospital for a second time. Panosky stated that David was 

in respiratory distress on this day and that the treating nurse could not 

reach a higher-level provider for over nine hours. In her deposition, 

Panosky testified that if a nurse could not reach a higher-level provider for 

such an extended period and the patient is in respiratory distress, the nurse

should have called 911.

¶41 In addition, Panosky testified about breaches of a different 

nature: following orders. Panosky stated that “it’s the nurse’s job to follow 

the orders that were written” and to make sure that an order gets done “the 

day it’s ordered.” She testified that, especially given David’s condition 

before his November 18 hospitalization, the Corizon nurse Daemmer 

breached this standard by waiting three days to complete one of David’s 

lab tests. A provider ordered the test on November 11. Panosky opined 

that, had Daemmer made sure the order was completed according to the 

standard, the results would have led any reasonable provider to send David 

to the hospital sooner, which would have increased his chance of survival.

¶42 Because Panosky provided competent expert opinion that 

Corizon’s nurses collectively breached identified standards of care, and Dr. 

Rosner opined that these breaches caused David’s death, see Part II(B) ¶ 37, 

the jury will not be left to infer causation regarding this claim.

¶43 Contrary to Corizon’s claims, Windhurst presented sufficient 

expert causation evidence to satisfy Sampson. A jury could reasonably rely 
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Opinion of the Court

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on this expert evidence to determine the cause of David’s death without 

making any impermissible inferences. Accordingly, when considering the 

causation evidence in the light most favorable to Windhurst, we conclude 

that the trial court erroneously granted summary judgment for Corizon.

D. Doctor Young

¶44 In partially granting Corizon’s summary judgment motion, 

the trial court also overlooked crucial details in Dr. Rosner’s report and 

deposition. Like the evidence establishing Corizon’s standard of care, see 

Part I ¶¶ 20–23, the report and deposition allege that Dr. Young’s breach of 

the relevant standard caused David’s death. The court based its ruling on 

its assessment that Windhurst failed to “specifically identify Corizon’s 

individual health-care-provider employees and agents,” and “explain [with 

corresponding expert testimony] how those employees and agents fell 

below the applicable standard of care . . . [and] how such failures were the 

cause of injury.” It also noted that “most of [Windhurst’s] malpractice 

allegations are against Corizon as an entity or as to its clinicians generally, 

not against specified individual health-care providers.” The trial court 

added that although Windhurst had “sprinkle[d] some allegations against 

specific individuals, . . . those allegations are so intertwined with the 

general allegations that it is unclear whether [Windhurst] has the requisite 

corresponding expert to make a prima facie showing that those individuals 

failed to meet the applicable standard of care, never mind that such a failure 

was also a proximate cause of injury.”

¶45 The record in this case, however, belies the trial court’s 

inability to “connect the dots” between Corizon’s individual health care 

providers and corresponding expert testimony on the standard of care and 

causation. For example, Dr. Rosner identified Dr.Murray Young, a Corizon 

employee, concluding that Dr. Young breached the applicable standard of 

care in treating David and that his breach contributed to David’s injuries. 

Specifically, Dr. Rosner noted that Dr. Young overlooked uremia as a cause 

of David’s itching and instead assumed that his skin condition resulted 

from “self-mutilation.” This assumption, Dr. Rosner opined, was not 

within the standard of care and caused David’s condition to worsen. The 
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Opinion of the Court

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trial court therefore erred by granting partial summary judgment to 

Corizon on the vicarious liability claim for Dr. Young’s breach.

III.

¶46 We conclude by turning to whether a registered nurse may 

testify regarding the cause of death in a medical malpractice case.

¶47 While the standard of care must be proven by expert medical 

testimony, Seisinger, 220 Ariz. at 94 ¶ 33, causation experts need only meet 

the requirements of Rule 702. See Rasor I, 244 Ariz. at 428 ¶ 18. As 

previously indicated, under Rule 702, “[f]or a witness to be qualified as an 

expert, he or she need only possess ‘skill and knowledge superior to that of 

[people] in general.’” State v. Romero, 239 Ariz. 6, 10 ¶ 17 (2016) (second 

alteration in original) (quoting State v. Girdler, 138 Ariz. 482, 490 (1983)). If 

a registered nurse possesses “specialized knowledge” that would “help the 

[jury] to understand the evidence or to determine a fact in issue” such as 

cause of death, then that individual may testify as an expert regarding that 

issue. See Ariz. R. Evid. 702.

¶48 Here, Corizon argued to the trial court that Panosky testified 

outside the scope of her practice and that she was not qualified to testify as 

an expert under Rule 702. However, because the trial court did not decide 

this issue, we decline to address the merits of this question on appeal. See 

State v. Salazar-Mercado, 234 Ariz. 590, 594 ¶ 13 (2014) (noting that the trial 

court determines whether Rule 702 is met, and appellate courts view that 

determination for an abuse of discretion). On remand, the trial court shall 

consider whether Panosky is qualified to testify as an expert regarding 

causation under Rule 702.

¶49 Corizon also asserts that Panosky’s causation testimony is 

duplicative and violates Arizona Rule of Civil Procedure 26(b)(4)(F)(i), 

which allows each side in a case to presumptively call only one retained or 

specially employed expert to testify on an issue. Although Corizon 

concedes in its supplemental brief that this “was not an issue in the court of 

appeals,” it nonetheless requests that we address this claim. Because the 

issue was not raised in the court of appeals or in Corizon’s petition for 
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Opinion of the Court

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review, and was not fully briefed, we decline to do so. See Ariz. R. Civ. 

App. P. 23(d)(1) (requiring petition for review to set forth the “issues that 

were decided by the Court of Appeals that the petitioner is presenting for 

Supreme Court review”).

CONCLUSION

¶50 Although we largely affirm its conclusions and approve of its 

reasoning, we vacate the court of appeals’ opinion to replace its reasoning 

with our own. We reverse the trial court’s grant of summary judgment and 

remand for the court to consider Corizon’s Rule 702 argument regarding 

Panosky and for further proceedings consistent with this opinion.