\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[ngerman,english]{babel}



\usepackage{float}








\begin{document}

\title{Effects of self-prone positioning method on oxygen saturation and
incidence of intubation in COVID-19 patients}



\author[1]{Joyce Wall}%
\author[1]{Rajiv Mallipudi}%
\author[1]{Erin Burch}%
\author[1]{Christopher Winterbottom}%
\author[1]{Shea Gregg}%
\affil[1]{Bridgeport Hospital}%


\vspace{-1em}



  
  \date{May 23, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
Study Objective: The purpose of this study was to determine the effects
of self-prone positioning on oxygenation in COVID-19 positive patients
utilizing supplemental oxygen and incidence of intubation. Method: A
one-year observational cohort pilot study at a major inner-city hospital
to evaluate self-proning on independent COVID-19 positive patients.
Qualified patients 18 years of age or older were recruited based on
inclusion and exclusion criteria. Data collection included vital signs
and timing for body position changes, and results were analyzed using
descriptive and inferential statistics. Results: Between April 2020 and
May 2021, 93 COVID-19 enrolled patients engaged in stomach or lateral
self-prone positioning. Eighty-four percent (n=78) of the population did
not require intubation, whereas 16\% (n=15) were intubated during their
hospital stay. SpO2 means were determined for each population and prone
position: Non-intubated (stomach) - before proning 93\% (IQR 4) and
during proning 95\% (IQR 3); (lateral) before proning 92\% (IQR 4) and
during proning 93\% (IQR 4). Intubated (stomach) - before proning 90\%
(IQR 7) and during proning 95\% (IQR 4); (lateral) before proning 92\%
(IQR 5) and during proning 95\% (IQR 5). Stomach proning significantly
increased oxygenation in the non-intubated (p \textless{}0.001) and
intubated (p 0.017) populations. Lateral proning significantly improved
oxygenation in the intubated population (p 0.002). Conclusion:
Self-proning in the independent COVID-19 positive patient on
supplemental oxygen was effective in improving SpO2 levels short-term.
Further controlled trial studies will elucidate the duration of proning
effects and reinforce its use as a noninvasive rescue intervention to
prevent intubation.%
\end{abstract}%



\sloppy


\textbf{Introduction}

Considering the current global pandemic and the consequential
devastating effects on the respiratory function of patients who test
positive for the coronavirus disease of 2019 (COVID-19), new ways are
being sought to improve health outcomes. Patients with COVID-19 often
present with severe hypoxemia and acute respiratory distress, leading to
supplemental oxygen therapy and intubation. Self-pronation is one
intervention that may improve low oxygen saturation levels (SpO2),
relieve shortness of breath (SOB), and potentially reduce intubation
rates in patients who develop respiratory symptoms of the virus.

Researchers reported that lying in the prone position improves lung
function in hospitalized patients with severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) (the virus that causes COVID-19) requiring
tracheal intubation and assisted
ventilation.\textsuperscript{{[}1{]}{[}2{]}{[}3{]}} As patients practice
prone positioning, they mitigate abnormal lung tissue strain and
injuries related to mechanical ventilation and decrease their risk of
intubation.\textsuperscript{{[}2{]}} Another study found that awake
early self-proning in the emergency department (ED) resulted in improved
oxygenation and decreased respiratory effort in the COVID-19 positive
patient.\textsuperscript{{[}4{]}} These findings provide evidence-based
information beneficial in the clinical setting to improve health
outcomes and mortality for COVID-19 positive
patients.\textsuperscript{{[}5{]}}

There is limited research in the area that directly addresses how a
patient's self-prone positioning (i.e., stomach versus lateral recumbent
proning) affects their oxygenation and outcomes. To further explore this
concept, we conducted an observational study to determine the effects of
self-proning on the independent and awake COVID-19 positive patient with
oxygen deficits. Our aim was to explore the effects of self-proning
methodology on a large population of admitted COVID-19 patients on
oxygenation and evaluate their tolerance level for the intervention and
the potential to avoid intubation. We hypothesize that all self-proning
positioning (including stomach and lateral recumbent proning) improves
oxygen saturation, relieves respiratory distress, and may reduce the
incidence of intubation in COVID-19 positive patients.

\textbf{Background}

Current research suggests that proning improves oxygenation in patients
with severe COVID-19 who are often hypoxemic and undergo endotracheal
intubation.\textsuperscript{{[}1{]}{[}2{]}{[}4{]}} The goal of awake
self-proning is to enhance oxygenation, improve respiratory function by
equalizing the pleural pressure gradient and distribution of
ventilation, and prevent intubation.\textsuperscript{{[}6{]}} Patients
who practice proning by lying on their stomachs increase aeration of
dense posterior lung segments. As they lie in the prone position,
gravity pushes secretions from the dense posterior lung segments toward
the less dense anterior lung tissue, which results in increased
perfusion and oxygenation to the posterior
lungs.\textsuperscript{{[}7{]}} The improved mobilization and drainage
of secretions from the posterior lungs increases oxygen saturation and
reduces the risk of intubation and ventilator-associated pneumonia
(VAP).\textsuperscript{{[}7{]}}

Anatomical and physiological changes occur in the lungs of the COVID-19
patient when they are in the prone position. Published reports from 1988
to 1991 showed computerized tomography (CT) scans of patients with acute
respiratory distress syndrome (ARDS) in the prone position, which
revealed redistribution of pathological posterobasal lung densities to
the new dependent lung positions.\textsuperscript{{[}7{]}} The
historical evidence led to the development of a pathophysiological
''sponge lung'' model, which simply means that when a sponge is soaked
in water, removed from the water, and placed in a horizontal or vertical
position, the water drainage slows to a stop, and the sponge becomes
wetter on the bottom with more empty pores on
top.\textsuperscript{{[}7{]}} The lungs have a sponge-like consistency
similar to the sponge model. The model also reflects the mechanism
through which the positive end-expiratory pressure (PEEP) opposes
compressing forces by changing lung volume and intrathoracic pressure;
when PEEP exceeds overlying pressure, it enables the dependent regions
of the lung to remain open.\textsuperscript{{[}7{]}}

Reports from clinical trials concluded that patients with severe ARDS
who lie in the prone position have a significant survival advantage.
Lung changes occur in the ARDS patient due to increased weight from
fluids (edema) that squeeze out gases from the posterior part of the
lungs or the most gravity-dependent
regions.\textsuperscript{{[}8{]}}Forces that result in compression
atelectasis or alveolar collapse in the dependent regions appear as
densities on CT scans.\textsuperscript{{[}9{]}} The shape of the lungs
and thoracic cavity, lung and cardiac mass, and displacement of the
abdomen contribute to changes in transpulmonary pressure and the
distribution of densities in the lungs due to gravitational
forces.\textsuperscript{{[}6{]}{[}9{]}} While prone, the weight of the
heart and abdominal contents are removed from the lungs, the production
of cytokines associated with inflammation is decreased, pleural pressure
and dorsal lung atelectasis decreases, and alveoli are opened with
improved oxygenation.\textsuperscript{{[}5{]}{[}7{]}{[}9{]}} PEEP and
lying in the prone position contributes to anterior lung de-recruitment,
dorsal lung recruitment with increased ventilation, and diminished
ventilator-induced injury (VILI) in ARDS patients due to improved
homogenous distribution of inflation and reduced lung
strain.\textsuperscript{{[}7{]}{[}9{]}{[}10{]}}

\textbf{Methods}

\emph{Setting and Study Design.} This was an observational cohort study
to assess the effect of the self-proning intervention on the independent
COVID-19 positive patient. It was conducted at Yale New Haven Health
Bridgeport Hospital, a 425-bed Level II Trauma center, and approved by
the Bridgeport Hospital Institutional Review Board (IRB). Patients
admitted to various locations throughout the hospital were considered
for this study, including medical and medical-surgical units, the
intermediate or Progressive Care Unit (PCU), Intensive Care Units
(ICUs), and the ED. Education involved in-servicing 366 hospital staff
members to include nurse leadership, nurse management, registered nurses
(RNs), physicians, patient care technicians (PCTs), and business
associates (BAs). They were informed on the purpose of self-proning and
its effects on the lungs in the independent COVID-19 positive patient
who did not require assistance with the intervention, how to qualify and
educate the patient, and the data collection process.

\emph{Patient Population} . The study population included 93 out of 98
recruited COVID-19 positive patients admitted to the hospital between
April 2020 and May 2021. The population was further subdivided into
nonintubated and intubated patients for data collection and comparison
purposes. Self-proning data was collected on the intubated patients
prior to undergoing mechanical ventilation. The study participants
utilized a nasal cannula (N/C) or non-rebreather (NRB) for supplemental
oxygenation and were instructed to perform a daily intervention to
self-prone over a 4-hour interval. Select COVID-19 positive patients on
high flow oxygen (HFO) were also included in the study in a
discretionary manner if they met inclusion criteria. Patients in the
recruited population who reported an alternative preferred body position
and did not engage in proning were excluded from the study.

\emph{Materials.} In-services on the self-proning protocol were
performed for the staff. They were provided with documentation and
ready-made packets for use on each patient who met the inclusion
criteria. Each packet had a preformed ''Self-Proning'' label on it with
a fill-in space for patient initials and contained the following (Figure
1A-1D): 1) an algorithm with a diagram decision tool for self-proning,
2) a protocol with methods and illustrations for the self-proning
procedure designed as a handout for the patient written in English and
Spanish, 3) a handout illustration comparing differences in lung
secretion placement in the supine and prone positions in the COVID-19
patient in an easy-to-view format, and 4) a documentation log with
columns for date, start and stop times, body position, total time, and
comments to be taped to the outside of the patient's room and filled in
by RNs and PCTs per body repositioning event.

Figure 1A. Contents of the Self-Proning Packet. Algorithm decision tool
for self-proning.

Figure 1B. Contents of the Self-Proning Packet. Patient protocol for
self-proning (English and Spanish versions were made available).

Figure 1C. Contents of the Self-Proning Packet. Illustration of the
lungs comparing differences in secretion placement in the supine and
prone positions in the COVID-19 patient.

Figure 1D. Contents of the Self-Proning Packet. Documentation data log.

\emph{Inclusion and exclusion criteria:} Recruitment for qualified
subjects was based on inclusion and exclusion criteria and determined by
the medical and research staff. We included patients who met the
following criteria: COVID-19 positive and admitted to the hospital, 18
years of age and older, male or female, utilizing a N/C or NRB, ability
to self-reposition, mentation intact, unobstructed airway. We excluded
patients based on the following criteria: COVID-19 negative, \textless{}
18 years old, not utilizing an N/C or NRB, not admitted to the hospital,
immediate need for intubation, altered mental status (AMS) or agitation,
trauma (spinal, thoracic, facial, or surgical), abdominal surgery,
inability to supine immediately, pregnancy, pressure wounds or ulcers.

\emph{Data Collection.} Vital signs were obtained by RNs or PCTs from a
telemonitor, pulse oximeter, or a vitals machine using standard
equipment and entered on a preformed documentation log kept outside of
the patient's room. The information included the date, vital signs
pre-proning, start time for any of four body positions (prone, right
side recumbent, sitting up in the Fowler's position, left side
recumbent), a second set of vital signs taken no sooner than 10 minutes
after each position change, stop time for the body position, total time
in the position, and a signature and comments column to denote variances
in the body positioning process, oxygenation, disposition, and patient
preferences (Figure 1D). The Epic electronic medical record system was
used to collect and confirm patient chart data, including demographics,
supplemental oxygenation, vital signs, medical history, and disposition.

\emph{Outcomes.} The primary outcome in this study for the COVID-19
positive patient on supplemental oxygen was the change in SpO2 at least
10 minutes after self-proning. The secondary outcome was the intubation
rate for patients who practiced self-proning.

\emph{Analysis.} We determined the change in SpO2 (including positive
and negative changes) before and during proning events for patients who
participated in the intervention. The data were analyzed utilizing
descriptive statistics in EXCEL to determine measures of central
tendency, frequency, variability, and quartile ranks. Further analysis
of the data was done utilizing inferential statistics to determine
confidence intervals, the coefficient of determination
(\emph{R\textsuperscript{2}} ) through linear regression, a \emph{t}
-test paired two sample for means (assuming unequal variances), and
calculated probability (\emph{p} -value). The independent variable (IV)
was the prone position (stomach or side-lying), and the dependent
variable (DV) was the oxygen status (SpO2) while in the prone position.

\textbf{Results}

The convenience sample in this observational cohort study included 93
out of 98 recruited patients who were COVID-19 positive and admitted to
the hospital in medical or intensive care units. In the nonintubated
population (\emph{n} =78), the median patient age (years) was 59
(interquartile range {[}IQR{]} 15, 29-84) and for the intubated
population (\emph{n} =15) it was 65 (IQR 18, 38-84). Length of stay
(LOS) in the hospital was 13 days for the nonintubated population with a
1\% mortality rate and 22 days for the intubated population with a 73\%
mortality rate (Table 1). Both populations engaged in stomach, lateral,
or a combination of both types of proning. The number of proning events,
median time for the event, and SpO2 values were recorded on the
documentation log (Figure 2).

Table 1. Sociodemographic and Baseline Clinical Characteristics

\par\null

Figure 2. Schematic Flowchart. Nonintubated and intubated (post proning)
patient populations engaged in self-proning. \emph{Abbreviations:} SpO2
= oxygen saturation.

The means for all documented stomach and lateral proning events for the
nonintubated population are reflected in Figure 3. The mean of the
starting SpO2 (pre-proning) for the 48 patients who were engaged in
stomach proning was 93\% (SD 3.3, IQR 4, 95\% confidence interval
{[}CI{]} 92 -- 94, 18). The mean for the change in SpO2 during proning
was 95\% (SD 2.4, IQR 3, 95\% CI 95 -- 96, 14). Skewness data for the
SpO2 was negative before (-0.5) and during proning (-0.9). A comparison
of the before and during proning SpO2 values yielded \emph{t} (170) =
-5.22, \emph{p} \textless{}0.001. The mean for changes in SpO2 before
lateral proning in this population was 92\% (SD 4.3, IQR 4, 95\% CI 92
-- 93, 25) and during proning 93\% (SD 3.6, IQR 4, 95\% CI 93 -- 94,
21). Skewness was negative (-1.4) before and during proning (-1.8).
Comparison of the changes in SpO2 values before and during proning
resulted in \emph{t} (205) = -1.92, \emph{p} 0.055 (Table 2).

Figure 3. Nonintubated Patient Population (stomach and lateral). Changes
in SpO2 are reflected in each graph before and during the proning
event.\emph{Upper graph} : Stomach proning (93 recorded SpO2 values)
mean before proning 93\% and during proning 95\%. \emph{Lower graph} :
Lateral semi-proning (107 recorded SpO2 values) mean before proning 92\%
and during proning 93\%.

Table 2. Self-Proning Patient Statistical Data

For the intubated population (Figure 4), the mean of the pre-proning
SpO2 values for stomach proning (\emph{n} =15) was 90\% (SD 5.0, IQR 7,
95\% CI 87 -- 93, 17). The mean for the change in SpO2 during proning
was 95\% (SD 3.3, IQR 4, 95\% CI 92 -- 97, 11). Skewness data for the
SpO2 was negative before (-0.8) and during proning (-0.1). A comparison
of the before and during proning SpO2 values yielded \emph{t} (19) =
-2.62, \emph{p} \textless{}0.017. The mean for changes in SpO2 before
lateral proning in this population was 92\% (SD 4.0, IQR 5, 95\% CI 90
-- 93, 17) and during proning 95\% (SD 2.8, IQR 5, 95\% CI 94 -- 96, 9).
Skewness was positive (0.004) before and during proning (0.1)
and\emph{t} (39) = -3.32, \emph{p} 0.002 (Table 2).

Figure 4. Intubated Patient Population (stomach and lateral). Changes in
SpO2 are reflected in each graph before and during the proning
event.\emph{Upper graph} : Stomach proning (12 recorded SpO2 values)
mean before proning 90\% and during proning 95\%. \emph{Lower graph} :
Lateral semi-proning (23 recorded SpO2 values) mean before proning 92\%
and during proning 95\%.

\emph{R\textsuperscript{2}} values (Table 2) representing the percentage
of variance for the changes in SpO2 (DV) explained by the prone position
(IV) are reflected in linear regression models for the nonintubated
(stomach proning \emph{R\textsuperscript{2}} \textless{}0.001, lateral
proning \emph{R\textsuperscript{2}} \textless{}0.001) and intubated
populations (stomach proning \emph{R\textsuperscript{2}} 0.028, lateral
proning \emph{R\textsuperscript{2}} 0.011) (Figure 5).

Figure 5. Linear Regression Models and \emph{R\textsuperscript{2}} .
Illustrations of the relationship between proning and the changes in
SpO2 for the patient populations. \emph{Upper and lower left} :
Nonintubated population - stomach
\emph{R\textsuperscript{2}}\textless{}0.001, lateral
\emph{R\textsuperscript{2}} \textless{}0.001.\emph{Upper and lower
right} : Intubated population - stomach\emph{R\textsuperscript{2}}
0.028, lateral \emph{R\textsuperscript{2}}0.011.

\textbf{Discussion}

The world is currently facing many challenges associated with the
COVID-19 pandemic and its potentially devastating systemic health
effects. The disease affects several body systems (i.e., respiratory,
cardiovascular, renal, hematological, neurological) with consequences
that manifest in multiple dimensions: mental health and substance abuse
issues, job loss, and social
inequities.\textsuperscript{{[}11{]}{[}12{]}} Clinicians are seeking
alternative strategies to manage the disease before it progresses into
severe ARDS, invasive mechanical ventilation, and increased mortality
rates.\textsuperscript{{[}4{]}{[}13{]}} Prone positioning is a
life-saving intervention recommended in evidence-based guidelines for
managing patients with ARDS as it reduces the risk of VILI and improves
respiratory mechanics.\textsuperscript{{[}14{]}{[}15{]}}

The data from our study on awake self-proning raise several points for
discussion. The \emph{R\textsuperscript{2}} values for the change in
SpO2 that occurred during a proning event (stomach or lateral) reflected
the linear relationship between the DV (change in SpO2) and the IV
(prone position). The percent variation in the data for the nonintubated
population for both stomach and lateral proning was \textless{} 0.1\%,
and for the intubated population, it was \textgreater{} 1\% for both
body positions (stomach 2.8\%, lateral 1.1\%). The low effect sizes for
these variations may be due to outliers or the exclusion of other
variables such as patient comorbidities. Additionally, the \emph{t}
-stat values for the change in SpO2 during stomach proning events for
both populations and lateral proning in the intubated population were
low (all were \textless{} -2.0, \emph{p} \textless{}0.05). For the
change in SpO2 during lateral proning in the nonintubated
population,\emph{t} -stat was \textgreater{} -2.0, \emph{p} 0.055. The
absolute\emph{t} -stat values were less than the \emph{df} for both
stomach and lateral proning in both populations. Based on the results,
we can conclude that a significant difference exists between the change
in SpO2 before proning and when a nonintubated patient assumes the
stomach position and when a patient who was subject to intubation
engages in either stomach or lateral positioning.

Although self-proning is widely practiced as a standard of care for
improving oxygenation, it is uncertain how long the effects last, if it
accelerates recovery time, and if it decisively prevents or delays the
need for intubation.\textsuperscript{{[}16{]}} Reports indicate that
proning longer throughout the day decreases the risk of lung
damage.\textsuperscript{{[}16{]}} The patients in our study engaged in
short-term proning (stomach and lateral), but the long-term effects are
not apparent. We included data for lateral positioning because of
patient preference and that it is associated with drainage of lung
secretions and improvement in pulmonary gas exchange in critically ill
patients.\textsuperscript{{[}17{]}} Based on our data, lateral proning
was more effective in the patients who were later intubated than those
who did not undergo mechanical ventilation. This may be due to other
unexplored conditions, such as differences in disease states and
medications. It is also important to note that the requirement for
mechanical ventilation for the intubated patients in this study (16\% of
the total population) cannot be related to a single proning event. These
patients were independent and able to perform awake self-proning before
intubation. The patient protocol was to change positions every 2 hours
(stomach, right and left lateral, and sitting up); however, proning
events were inconsistent and based on the patient's tolerance and
position preferences. As a result, it is unclear if more consistent
self-proning would have decreased the incidence of intubation in the
patient population. A dedicated team who could consistently monitor the
independent awake self-proner throughout each shift during their
hospital stay would help minimize or avoid non-conforming proning times
and events.

Our study population (N=93) is one of the largest in size in the area of
self-proning in COVID-19 positive patients over a one-year interval. The
candidates for this minimal risk intervention were acutely suffering SOB
from the systemic effects of COVID-19, and the results from this study
indicated that changes in SpO2 were significant when self-proning on the
stomach or in the lateral position. The lack of consistency in our data
may weaken the argument for short-term and long-term proning as a
potential rescue intervention; however, based on the results,
self-proning (stomach or lateral) resulted in improved gas exchange and
was widely and effectively utilized in accordance with safety guidelines
during the pandemic throughout the hospital where this study took place.
Although the benefit of proning in the nonintubated patient may not be
solely related to improved oxygenation, it is advantageous as a
low-cost, scalable intervention that is easily implemented and may save
the lives of those at risk of intubation.\textsuperscript{{[}18{]}} When
safely guided and controlled, proning may be beneficial as a rescue
strategy and may help avoid endotracheal intubation and its potentially
harmful effects on hypoxemic COVID-19
patients.\textsuperscript{{[}16{]}}

\textbf{Implications}

The results from this pilot study provide evidence-based information
beneficial to the clinical setting and have implications for an
effective rescue intervention for COVID-19 positive patients in
respiratory distress that can be performed independently. As research
expands in the area that directly addresses the health crisis and what
hospitals and the multidisciplinary team can do using a simple measure
to alleviate respiratory symptoms associated with the virus and
avoidance of extraneous interventions, we suggest a more comprehensive,
protocolized, and guided study that focuses on short-term and long-term
effects from stomach and lateral proning in patients who are respiratory
compromised.

\textbf{Limitations}

Several limitations in this study may have influenced the outcomes.
Recruitment of qualified patients was minimized due to nursing staff
concerns about increased workload and exposure to COVID-19 and overuse
of personal protective equipment (PPE) to obtain vital signs before and
after position changes. Nurses were thus instructed to gather data on
patient adherence to the protocol once per shift in alignment with
scheduled nursing tasks and to document vital signs from patient
monitors that could be viewed through a glass window on the door of the
room (not all rooms had glass windows, so this alternative was limited).
Not all staff were in-serviced on the protocol, so changing shifts and
turnover in nursing staff also contributed to inconsistencies and
limited potential for recruiting newly admitted qualified patients.
Patient comments regarding proning events were not consistently entered
on the documentation log, so lack of this personal information limited
feedback that may have helped optimize the protocol and increase
compliance. The patients in this study came from a convenience sample
presenting to one inner-city hospital and may not represent other
populations. Their treatment plans and aspects of care were not
controlled, which may have introduced confounding variables that
influenced changes in SpO2 levels (the effects may result from an
unrecognized alternate treatment rather than from proning). The lack of
a control group also increases selection bias, decreases study power,
threatens internal and external validity, and weakens the ability to
draw conclusions about self-proning in these patients. A randomized
prospective study that observes outcomes of proning in the COVID-19
positive patient and other aspects of their care would help determine a
causal relationship between self-proning, improved oxygenation, and
incidence of intubation. It would also be prudent to group patients with
similar case mix index profiles and comorbidities to assess overall
outcomes for those who perform proning.

\textbf{Conclusion}

Based on the data in this study, the type of self-proning positioning,
whether stomach or lateral recumbent, in the awake independent patient
effectively improved oxygenation; however, the duration of the effect
and prevention of intubation is unclear. Further controlled studies
would help strengthen the support of self-proning as a cost-effective,
practical consideration, and noninvasive modality in the early
management of COVID-19 positive patients with respiratory compromise.

\textbf{Acknowledgments}

We wish to acknowledge and thank all the participating staff at
Bridgeport Hospital, which includes the educators (Julie Bergeron, RN;
Ann Dyke, APRN; Heather Grunewald, RN; Catrina Lanouette, RN; Marlene,
Schmidt, RN; Michael Williams, MC), nursing leadership, unit nurse
managers and assistant managers, Claudette Thyme, Kara Burdick, Lisa
Aplin, Trish McGahan, Ebony Johnson, administrative staff (Theresa
Pauciello), all RNs, PCTs and BAs, Monique Misra, MD, Kristan Sikorski,
MD, and the entire Department of Hospital Medicine team for implementing
the use of the proning protocol in COVID-19 patients under the
hospitalist service. All these individuals gave so selflessly of their
time to be an instrumental part of this research study. We appreciate
your above and beyond dedication and commitment to providing quality
care for our patients.

\textbf{References}

\begin{enumerate}
\tightlist
\item
  Anand S, Baishya M, Singh A, Khanna P. Effect of awake prone
  positioning in COVID-19 patients - A systematic review. \emph{Trends
  in Anaesthesia \& Critical Care} 2021;36:17-22.
\item
  Coppo A, Bellani G, Winterton D, Di Pierro M, Soria A, Faverio P,
  Cairo M, Mori S, Messinesi G, Contro E, Bonfanti P, Benini A, Grazia
  Valsecchi M, Antolini L, Foti G. Feasibility and physiological effects
  of prone positioning in non-intubated patients with acute respiratory
  failure due to COVID-19 (PRON-COVID): A prospective cohort
  study.\emph{Lancet Respir Med} 2020;8:765-774.
\item
  Pan C, Chen L, Lu C, Zhang W, Xia J, Sklar MC, Du B, Brochard L, Qui
  H. Lung recruitability in COVID-19--associated acute respiratory
  distress syndrome: A single-center observational study. \emph{Am J
  Respir Crit Care Med} 2020;201:1294-1297.
\item
  Caputo ND, Strayer RJ, Levitan R. Early self-proning in awake,
  non-intubated patients in the Emergency Department: A single ED's
  experience during the COVID-19 pandemic. \emph{Acad Emerg
  Med}2020;27:375-378.
\item
  Henderson WR, Griesdale DEG, Dominelli P, Ronco JJ. Does prone
  positioning improve oxygenation and reduce mortality in patients with
  acute respiratory distress syndrome? \emph{Can Respir
  J}2014;21:213-215.
\item
  Pelosi P, Brazzi L, Gattinoni L. Prone position in acute respiratory
  distress syndrome. \emph{Eur Respir J} 2002;20:1017-1028.
\item
  Koulouras V, Papathanakos, G, Papathanasiou A, Nakos G. Efficacy of
  prone position in acute respiratory distress syndrome patients: A
  pathophysiology-based review. \emph{World J Crit Care
  Med}2016;5:121-136.
\item
  Gattinoni L, Meissner K, Marini JJ. The baby lung and the COVID-19
  era. \emph{Intensive Care Med} 2020;46:1438-1440.
\item
  Gattinoni L, Pesenti A, Carlessom E. (2013). Body position changes
  redistribute lung computed-tomographic density in patients with acute
  respiratory failure: Impact and clinical fallout through the following
  20 years. \emph{Intensive Care Med} 2013;39:1909-1915.
\item
  Beitler JR, Malhotra A, Thompson BT. Ventilator-induced lung
  injury.\emph{Clin Chest Med} 2016;37:633-646.
\item
  Temgoua MN, Endomba FT, Nkeck JR, Kenfack GU, Tochie JN, Essouma M.
  Coronavirus disease 2019 (COVID-19) as a multi-systemic disease and
  its impact in low- and middle-income countries (LMICs). \emph{SN Compr
  Clin Med} 2020;2:1377-1387.
\item
  Ruffolo M, Price D, Schoultz M, Leung J, Bonsaksen T, Thygesesn H,
  \selectlanguage{ngerman}Østertun Geirdal A. Employment uncertainty and mental health during
  the COVID-19 pandemic initial social distancing implementation: A
  cross-national study. \emph{Glob Soc Welf} 2021;8:141-150.
\item
  Auld SC, Caridi-Scheible M, Blum JM, Robichaux C, Kraft C, Jacob JT,
  Jabaley CS, Carpenter D, Kaplow R, Hernandez-Romieu AC, Adelman MW,
  Martin GS, Coopersmith CM, Murphy DJ, Emory COVID-19 Quality and
  Clinical Research Collaborative. ICU and ventilator mortality among
  critically ill adults with coronavirus disease 2019. \emph{Crit Care
  Med} 2020;48:e799--e804.
\item
  McNicholas B, Cosgrave D, Giacomini C, Brennan A, Laffey JG. Prone
  positioning in COVID-19 acute respiratory failure: Just do
  it?.\emph{Br J Anaesth} 2020;125:440--443.
\item
  Guérin C, Reignier J, Richard JC, Beuret P, Gacouin A., Boulain T,
  Mercier E, Badet M, Mercat A, Baudin O, Clavel M, Chatellier D, Jaber
  S, Rosselli S, Mancebo J, Sirodot M, Hilbert G, Bengler C, Richecoeur
  J, Gainnier M, Bayle F, Bourdin G, Leray V, Girard R, Baboi L, Ayzac
  L, PROSEVA Study Group. Prone positioning in severe acute respiratory
  distress syndrome. \emph{N Engl J Med} 2013;368:2159-2168.
\item
  Gattinoni L, Taccone P, Carlesso E, Marini JJ. Prone position in acute
  respiratory distress syndrome. Rationale, indications, and
  limits.\emph{Am J Respir Crit Care Med} 2013;188:1286-1293.
\item
  Zhong Ni, Kaige Wang, Ting Wang, Yuenan Ni, Wei Huang, Ping Zhu, Tao
  Fan, Ye Wang, Bo Wang, Jun Deng, Zhicheng Qian, Jiasheng Liu, Wenhao
  Cai, Shanling Xu, Yu Du, Gang Wang, Zongan Liang, Weimin Li, Jianfei
  Luo, Fengming Luo, Dan Liu. Efficacy of early prone or lateral
  positioning in patients with severe COVID-19: A single-center
  prospective cohort. \emph{Precis Clin Med} 2020;3:260-271.
\item
  Damarla M, Zaeh S, Niedermeyer S, Merck S, Niranjan-Azadi A, Broderick
  B, Punjabi N. Prone positioning of nonintubated patients with
  COVID-19. \emph{Am J Respir Crit Care Med} 2020;202:604--606.
\end{enumerate}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

Figure 1A. Contents of the Self-Proning Packet. Algorithm decision tool
for self-proning.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

Figure 1B. Contents of the Self-Proning Packet. Patient protocol for
self-proning (English and Spanish versions were made available).\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

Figure 1C. Contents of the Self-Proning Packet. Illustration of the
lungs comparing differences in secretion placement in the supine and
prone positions in the COVID-19 patient.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image4/image4}

\end{center}
\end{figure}

Figure
1D. Contents of the Self-Proning Packet. Documentation data log.

Table 1. Sociodemographic and Baseline Clinical Characteristics\selectlanguage{english}
\begin{longtable}[]{@{}lll@{}}
\toprule
Sociodemographic and Baseline Clinical Characteristics &
\textbf{Nonintubated population} & \textbf{Intubated
population*}\tabularnewline
\midrule
\endhead
Population size & \emph{n}=78 & \emph{n}=15\tabularnewline
\vtop{\hbox{\strut Age (years):
Median}\hbox{\strut IQR}\hbox{\strut Range}} & 59 15 29 - 84 & 65 18 38
- 84\tabularnewline
\vtop{\hbox{\strut Sex: Female}\hbox{\strut Male}} & 29\% 71\% & 53\%
47\%\tabularnewline
LOS (days) & 13 & 22\tabularnewline
Deceased & 1\% & 73\%\tabularnewline
\bottomrule
\end{longtable}

IQR = Interquartile range; LOS = Length of stay. \textbf{*} Proning
event data for intubated patients were collected prior to intubation.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image5/image5}

\end{center}
\end{figure}

Figure 2. Schematic Flowchart. Nonintubated and intubated (post proning)
patient populations engaged in self-proning. \emph{Abbreviations:} SpO2
= oxygen saturation.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image6/image6}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image7/image7}

\end{center}
\end{figure}

Figure 3. Nonintubated Patient Population (stomach and lateral). Changes
in SpO2 are reflected in each graph before and during the proning
event.\emph{Upper graph} : Stomach proning (93 recorded SpO2 values)
mean before proning 93\% and during proning 95\%. \emph{Lower graph} :
Lateral semi-proning (107 recorded SpO2 values) mean before proning 92\%
and during proning 93\%.

Table 2. Self-Proning Patient Statistical Data\selectlanguage{english}
\begin{longtable}[]{@{}llllll@{}}
\toprule
\begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
Self-Proning Statistical Data \textbf{Prone position}\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\emph{Nonintubated population (n=78)}\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\emph{Nonintubated population (n=78)}\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\emph{Intubated population (n=15)*}\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\emph{Intubated population (n=15)*}\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{SpO2} \textbf{(pre-proning)}\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{Change in SpO2} \textbf{(during proning)}\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{SpO2} \textbf{(pre-proning)}\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{Change in SpO2} \textbf{(during proning)}\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\textbf{Stomach}\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 93\% \emph{SD} 3.3 IQR 4 95\% CI 92 - 94 Range 18 Skewness
-0.5\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 95\% \emph{SD} 2.4 IQR 3 95\% CI 95 - 96 Range 14 Skewness -0.9
\emph{R\textsuperscript{2}} \textless{}0.001 \emph{t}(170) = -5.22,
\emph{p} \textless{}0.001\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 90\% \emph{SD} 5.0 IQR 7 95\% CI 87 - 93 Range 17 Skewness
-0.8\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 95\% \emph{SD} 3.3 IQR 4 95\% CI 92 - 97 Range 11 Skewness -0.1
\emph{R\textsuperscript{2}} 0.028 \emph{t}(19) = -2.62, \emph{p}
0.017\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\textbf{Lateral}\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 92\% \emph{SD} 4.3 IQR 4 95\% CI 92 - 93 Range 25 Skewness
-1.4\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 93\% \emph{SD} 3.6 IQR 4 95\% CI 93 -- 94 Range 21 Skewness
-1.8 \emph{R\textsuperscript{2}} \textless{}0.001 \emph{t}(205) = -1.92,
\emph{p} 0.055\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 92\% \emph{SD} 4.0 IQR 5 95\% CI 90 - 93 Range 17 Skewness
0.004\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
\emph{M} 95\% \emph{SD} 2.8 IQR 5 95\% CI 94 - 96 Range 9 Skewness 0.1
\emph{R\textsuperscript{2}} 0.011 \emph{t}(39) = -3.32, \emph{p}
0.002\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

\emph{M} = mean; \emph{SD} = Standard deviation; IQR = Interquartile
range; CI = Confidence interval; \emph{R\textsuperscript{2}} =
Coefficient of determination; \emph{t} = t-statistic; \emph{p} =
probability value. \textbf{*} SpO2 data for intubated patients were
collected prior to intubation.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image8/image8}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image9/image9}

\end{center}
\end{figure}

Figure 4. Intubated Patient Population (stomach and lateral). Changes in
SpO2 are reflected in each graph before and during the proning
event.\emph{Upper graph} : Stomach proning (12 recorded SpO2 values)
mean before proning 90\% and during proning 95\%. \emph{Lower graph} :
Lateral semi-proning (23 recorded SpO2 values) mean before proning 92\%
and during proning 95\%.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image10/image10}

\end{center}
\end{figure}

Figure 5. Linear Regression Models and \emph{R\textsuperscript{2}} .
Illustrations of the relationship between proning and the changes in
SpO2 for the patient populations. \emph{Upper and lower left} :
Nonintubated population - stomach
\emph{R\textsuperscript{2}}\textless{}0.001, lateral
\emph{R\textsuperscript{2}} \textless{}0.001.\emph{Upper and lower
right} : Intubated population - stomach\emph{R\textsuperscript{2}}
0.028, lateral \emph{R\textsuperscript{2}}0.011.

\selectlanguage{english}
\FloatBarrier
\end{document}

