Browsing by Author "Moon, Richard E"

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Open Access
A prospective comparison of a noninvasive cardiac output monitor versus esophageal doppler monitor for goal-directed fluid therapy in colorectal surgery patients
(Anesthesia and Analgesia, 2014-01-01) Waldron, Nathan H; Miller, Timothy E; Thacker, Julie K; Manchester, Amy K; White, William D; Nardiello, John; Elgasim, Magdi A; Moon, Richard E; Gan, Tong J
Copyright © 2014 International Anesthesia Research Society.BACKGROUND: Goal-directed fluid therapy (GDFT) is associated with improved outcomes after surgery. The esophageal Doppler monitor (EDM) is widely used, but has several limitations. The NICOM, a completely noninvasive cardiac output monitor (Cheetah Medical), may be appropriate for guiding GDFT. No prospective studies have compared the NICOM and the EDM. We hypothesized that the NICOM is not significantly different from the EDM for monitoring during GDFT. METHODS: One hundred adult patients undergoing elective colorectal surgery participated in this study. Patients in phase I (n = 50) had intraoperative GDFT guided by the EDM while the NICOM was connected, and patients in phase II (n = 50) had intraoperative GDFT guided by the NICOM while the EDM was connected. Each patient's stroke volume was optimized using 250- mL colloid boluses. Agreement between the monitors was assessed, and patient outcomes (postoperative pain, nausea, and return of bowel function), complications (renal, pulmonary, infectious, and wound complications), and length of hospital stay (LOS) were compared. RESULTS: Using a 10% increase in stroke volume after fluid challenge, agreement between monitors was 60% at 5 minutes, 61% at 10 minutes, and 66% at 15 minutes, with no significant systematic disagreement (McNemar P > 0.05) at any time point. The EDM had significantly more missing data than the NICOM. No clinically significant differences were found in total LOS or other outcomes. The mean LOS was 6.56 ± 4.32 days in phase I and 6.07 ± 2.85 days in phase II, and 95% confidence limits for the difference were -0.96 to +1.95 days (P = 0.5016). CONCLUSIONS: The NICOM performs similarly to the EDM in guiding GDFT, with no clinically significant differences in outcomes, and offers increased ease of use as well as fewer missing data points. The NICOM may be a viable alternative monitor to guide GDFT.
Open Access
An Undiagnosed Paraganglioma in a 58-Year-Old Female Who Underwent Tumor Resection.
(Case Rep Anesthesiol, 2017) Fox, William C; Read, Matthew; Moon, Richard E; Moretti, Eugene W; Colin, Brian J
Paragangliomas and pheochromocytomas are rare neuroendocrine tumors that can have high morbidity and mortality if undiagnosed. Here we report a case of an undiagnosed paraganglioma in a 58-year-old female who underwent tumor resection. The patient became severely hypertensive intraoperatively with paroxysmal swings in blood pressure and then later became acutely hypotensive after tumor removal. She was managed in the surgical intensive care unit (SICU) postoperatively and discharged from the hospital without acute complications. We briefly discuss the epidemiology, clinical presentation, perioperative management, and possible complications of these tumors to assist healthcare providers if one were to encounter them.
Open Access
Arterial Blood Gas Analysis in Breath-Hold Divers at Depth.
(Frontiers in physiology, 2018-01) Bosco, Gerardo; Rizzato, Alex; Martani, Luca; Schiavo, Simone; Talamonti, Ennio; Garetto, Giacomo; Paganini, Matteo; Camporesi, Enrico M; Moon, Richard E
The present study aimed to evaluate the partial pressure of arterial blood gases in breath-hold divers performing a submersion at 40 m. Eight breath-hold divers were enrolled for the trials held at "Y-40 THE DEEP JOY" pool (Montegrotto Terme, Padova, Italy). Prior to submersion, an arterial cannula in the radial artery of the non-dominant limb was positioned. All divers performed a sled-assisted breath-hold dive to 40 m. Three blood samplings occurred: at 10 min prior to submersion, at 40 m depth, and within 2 min after diver's surfacing and after resuming normal ventilation. Blood samples were analyzed immediately on site. Six subjects completed the experiment, without diving-related problems. The theoretically predicted hyperoxia at the bottom was observed in 4 divers out of 6, while the other 2 experienced a reduction in the partial pressure of oxygen (paO2) at the bottom. There were no significant increases in arterial partial pressure of carbon dioxide (paCO2) at the end of descent in 4 of 6 divers, while in 2 divers paCO2 decreased. Arterial mean pH and mean bicarbonate ( HCO3- ) levels exhibited minor changes. There was a statistically significant increase in mean arterial lactate level after the exercise. Ours was the first attempt to verify real changes in blood gases at a depth of 40 m during a breath-hold descent in free-divers. We demonstrated that, at depth, relative hypoxemia can occur, presumably caused by lung compression. Also, hypercapnia exists at depth, to a lesser degree than would be expected from calculations, presumably because of pre-dive hyperventilation and carbon dioxide distribution in blood and tissues.
Open Access
Arterial blood gases in divers at surface after prolonged breath-hold.
(European journal of applied physiology, 2020-02) Bosco, Gerardo; Paganini, Matteo; Rizzato, Alex; Martani, Luca; Garetto, Giacomo; Lion, Jacopo; Camporesi, Enrico M; Moon, Richard E
PURPOSE:Adaptations during voluntary breath-hold diving have been increasingly investigated since these athletes are exposed to critical hypoxia during the ascent. However, only a limited amount of literature explored the pathophysiological mechanisms underlying this phenomenon. This is the first study to measure arterial blood gases immediately before the end of a breath-hold in real conditions. METHODS:Six well-trained breath-hold divers were enrolled for the experiment held at the "Y-40 THE DEEP JOY" pool (Montegrotto Terme, Padova, Italy). Before the experiment, an arterial cannula was inserted in the radial artery of the non-dominant limb. All divers performed: a breath-hold while moving at the surface using a sea-bob; a sled-assisted breath-hold dive to 42 m; and a breath-hold dive to 42 m with fins. Arterial blood samples were obtained in four conditions: one at rest before submersion and one at the end of each breath-hold. RESULTS:No diving-related complications were observed. The arterial partial pressure of oxygen (96.2 ± 7.0 mmHg at rest, mean ± SD) decreased, particularly after the sled-assisted dive (39.8 ± 8.7 mmHg), and especially after the dive with fins (31.6 ± 17.0 mmHg). The arterial partial pressure of CO2 varied somewhat but after each study was close to normal (38.2 ± 3.0 mmHg at rest; 31.4 ± 3.7 mmHg after the sled-assisted dive; 36.1 ± 5.3 after the dive with fins). CONCLUSION:We confirmed that the arterial partial pressure of oxygen reaches hazardously low values at the end of breath-hold, especially after the dive performed with voluntary effort. Critical hypoxia can occur in breath-hold divers even without symptoms.
Open Access
Blue Vision (Cyanopsia) Associated With TURP Syndrome: A Case Report.
(A&A practice, 2018-05-29) Fox, William C; Moon, Richard E
There have been many complications associated with transurethral resection of the prostate (TURP), known as TURP syndrome. Of the various irrigation fluids used for TURP, glycine irrigant has been historically popular given its relatively low cost. It is also a nonconductive solution and only slightly hypoosmolar, reducing the risk of burn injury or significant hemolysis. However, there have been many case reports of central nervous system toxicity such as transient blindness and encephalopathy related to glycine toxicity. Here, we report blue vision (cyanopsia), which has never been reported as a symptom of TURP syndrome.
Open Access
Deaths in triathletes: immersion pulmonary oedema as a possible cause.
(BMJ Open Sport Exerc Med, 2016) Moon, Richard E; Martina, Stefanie D; Peacher, Dionne F; Kraus, William E
BACKGROUND/AIM: To address the question as to whether immersion pulmonary oedema (IPO) may be a common cause of death in triathlons, markers of swimming-induced pulmonary oedema (SIPO) susceptibility were sought in triathletes' postmortem examinations. METHODS: Deaths while training for or during triathlon events in the USA and Canada from October 2008 to November 2015 were identified, and postmortem reports requested. We assessed obvious causes of death; the prevalence of left ventricular hypertrophy (LVH); comparison with healthy triathletes. RESULTS: We identified 58 deaths during the time period of the review, 42 (72.4%) of which occurred during a swim. Of these, 23 postmortem reports were obtained. Five individuals had significant (≥70%) coronary artery narrowing; one each had coronary stents; retroperitoneal haemorrhage; or aortic dissection. 9 of 20 (45%) with reported heart mass exceeded 95th centile values. LV free wall and septal thickness were reported in 14 and 9 cases, respectively; of these, 6 (42.9%) and 4 (44.4%) cases exceeded normal values. 6 of 15 individuals (40%) without an obvious cause of death had excessive heart mass. The proportion of individuals with LVH exceeded the prevalence in the general triathlete population. CONCLUSIONS: LVH-a marker of SIPO susceptibility-was present in a greater than the expected proportion of triathletes who died during the swim portion. We propose that IPO may be a significant aetiology of death during the swimming phase in triathletes. The importance of testing for LVH in triathletes as a predictor of adverse outcomes should be explored further.
Open Access
Diagnosis of Swimming Induced Pulmonary Edema-A Review.
(Frontiers in physiology, 2017-01) Grünig, Hannes; Nikolaidis, Pantelis T; Moon, Richard E; Knechtle, Beat
Swimming induced pulmonary edema (SIPE) is a complication that can occur during exercise with the possibility of misdiagnosis and can quickly become life threatening; however, medical literature infrequently describes SIPE. Therefore, the aim of this review was to analyse all individual cases diagnosed with SIPE as reported in scientific sources, with an emphasis on the diagnostic pathways and the key facts resulting in its diagnosis. Due to a multifactorial and complicated pathophysiology, the diagnosis could be difficult. Based on the actual literature, we try to point out important findings regarding history, conditions, clinical findings, and diagnostic testing helping to confirm the diagnosis of SIPE. Thirty-eight cases from seventeen articles reporting the diagnosis of SIPE were selected. We found remarkable differences in the individual described diagnostic pathways. A total of 100% of the cases suffered from an acute onset of breathing problems, occasionally accompanied by hemoptysis. A total of 73% showed initial hypoxemia. In most of the cases (89%), an initial chest X-Ray or chest CT was available, of which one-third (71%) showed radiological signs of pulmonary edema. The majority of the cases (82%) experienced a rapid resolution of symptoms within 48 h, the diagnostic hallmark of SIPE. Due to a foreseeable increase in participation in swimming competitions and endurance competitions with a swimming component, diagnosis of SIPE will be important, especially for medical teams caring for these athletes.
Open Access
Effects of high-intensity interval training with hyperbaric oxygen.
(Frontiers in physiology, 2022-01) Alvarez Villela, Miguel; Dunworth, Sophia A; Kraft, Bryan D; Harlan, Nicole P; Natoli, Michael J; Suliman, Hagir B; Moon, Richard E
Hyperbaric Oxygen (HBO₂) has been proposed as a pre-conditioning method to enhance exercise performance. Most prior studies testing this effect have been limited by inadequate methodologies. Its potential efficacy and mechanism of action remain unknown. We hypothesized that HBO₂ could enhance aerobic capacity by inducing mitochondrial biogenesis via redox signaling in skeletal muscle. HBO₂ was administered in combination with high-intensity interval training (HIIT), a potent redox stimulus known to induce mitochondrial biogenesis. Aerobic capacity was tested during acute hypobaric hypoxia seeking to shift the limiting site of whole body V̇O2 from convection to diffusion, more closely isolating any effect of improved oxidative capacity. Healthy volunteers were screened with sea-level (SL) V̇O₂peak testing. Seventeen subjects were enrolled (10 men, 7 women, ages 26.5±1.3 years, BMI 24.6±0.6 kg m^-2, V̇O₂peak SL = 43.4±2.1). Each completed 6 HIIT sessions over 2 weeks randomized to breathing normobaric air, "HIIT+Air" (PiO₂ = 0.21 ATM) or HBO₂ (PiO₂ = 1.4 ATM) during training, "HIIT+HBO₂" group. Training workloads were individualized based on V̇O₂peak SL test. Vastus Lateralis (VL) muscle biopsies were performed before and after HIIT in both groups. Baseline and post-training V̇O₂peak tests were conducted in a hypobaric chamber at PiO2 = 0.12 ATM. HIIT significantly increased V̇O₂peak in both groups: HIIT+HBO₂ 31.4±1.5 to 35.2±1.2 ml kg^-1·min^-1 and HIIT+Air 29.0±3.1 to 33.2±2.5 ml kg^-1·min^-1 (p = 0.005) without an additional effect of HBO₂ (p = 0.9 for interaction of HIIT x HBO₂). Subjects randomized to HIIT+HBO₂ displayed higher skeletal muscle mRNA levels of PPARGC1A, a regulator of mitochondrial biogenesis, and HK2 and SLC2A4, regulators of glucose utilization and storage. All other tested markers of mitochondrial biogenesis showed no additional effect of HBO₂ to HIIT. When combined with HIIT, short-term modest HBO₂ (1.4 ATA) has does not increase whole-body V̇O₂peak during acute hypobaric hypoxia. (ClinicalTrials.gov Identifier: NCT02356900; https://clinicaltrials.gov/ct2/show/NCT02356900).
Open Access
Efficacy of Hyperbaric Oxygen for Carbon Monoxide Poisoning.
(Chest, 2018-03) Moon, Richard E; Hampson, Neil B
Open Access
Enhanced recovery protocols for colorectal surgery and postoperative renal function: a retrospective review.
(Perioper Med (Lond), 2017) Horres, Charles R; Adam, Mohamed A; Sun, Zhifei; Thacker, Julie K; Moon, Richard E; Miller, Timothy E; Grant, Stuart A
BACKGROUND: While enhanced recovery protocols (ERPs) reduce physiologic stress and improve outcomes in general, their effects on postoperative renal function have not been directly studied. METHODS: Patients undergoing major colorectal surgery under ERP (February 2010 to March 2013) were compared with a traditional care control group (October 2004 October 2007) at a single institution. Multivariable regression models examined the association of ERP with postoperative creatinine changes and incidence of postoperative acute kidney dysfunction (based on the Risk, Injury, Failure, Loss, and End-stage renal disease criteria). RESULTS: Included were 1054 patients: 590 patients underwent surgery with ERP and 464 patients without ERP. Patient demographics were not significantly different. Higher rates of neoplastic and inflammatory bowel disease surgical indications were found in the ERP group (81 vs. 74%, p = 0.045). Patients in the ERP group had more comorbidities (ASA ≥ 3) (62 vs. 40%, p < 0.001). In unadjusted analysis, postoperative creatinine increase was slightly higher in the ERP group compared with control (median 0.1 vs. 0 mg/dL, p < 0.001), but levels of postoperative acute kidney injury were similar in both groups (p = 0.998). After adjustment with multivariable regression, postoperative changes in creatinine were similar in ERP vs. control (p = 0.25). CONCLUSIONS: ERP in colorectal surgery is not associated with a clinically significant increase in postoperative creatinine or incidence of postoperative kidney injury. Our results support the safety of ERPs in colorectal surgery and may promote expanding implementation of these protocols. TRIAL REGISTRATION: Not applicable, prospective data collection and retrospective chart review only.
Open Access
Environmental Physiology and Diving Medicine.
(Frontiers in psychology, 2018-01) Bosco, Gerardo; Rizzato, Alex; Moon, Richard E; Camporesi, Enrico M
Man's experience and exploration of the underwater environment has been recorded from ancient times and today encompasses large sections of the population for sport enjoyment, recreational and commercial purpose, as well as military strategic goals. Knowledge, respect and maintenance of the underwater world is an essential development for our future and the knowledge acquired over the last few dozen years will change rapidly in the near future with plans to establish secure habitats with specific long-term goals of exploration, maintenance and survival. This summary will illustrate briefly the physiological changes induced by immersion, swimming, breath-hold diving and exploring while using special equipment in the water. Cardiac, circulatory and pulmonary vascular adaptation and the pathophysiology of novel syndromes have been demonstrated, which will allow selection of individual characteristics in order to succeed in various environments. Training and treatment for these new microenvironments will be suggested with description of successful pioneers in this field. This is a summary of the physiology and the present status of pathology and therapy for the field.
Open Access
Hyperbaric oxygen as a treatment for COVID-19 infection?
(Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc, 2020-01) Moon, Richard E; Weaver, Lindell K
Recently the internet has been abuzz with new ideas to treat COVID-19, including hyperbaric oxygen (HBO2) therapy, undoubtedly driven by the fact that until recently there have been few therapeutic options for this highly contagious and often lethal infection. . . . Refractory hypoxemia is certainly treatable with hyperbaric oxygen due to the obvious effect of increasing inspired oxygen partial pressure (PO2), the major reason for using HBO2 for its established indications. However, the length of time during which patients can safely be administered HBO2 inside a chamber is limited, due to practical issues of confinement and isolation from other necessary medical interventions, but also because of oxygen toxicity.
Open Access
Hyperbaric oxygen for decompression sickness.
(Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc, 2021-01) Moon, Richard E; Mitchell, Simon J
Decompression sickness (DCS, "bends") is caused by formation of bubbles in tissues and/or blood when the sum of dissolved gas pressures exceeds ambient pressure (supersaturation). This may occur when ambient pressure is reduced during any of the following: ascent from a dive; depressurization of a hyperbaric chamber; rapid ascent to altitude in an unpressurized aircraft or hypobaric chamber; loss of cabin pressure in an aircraft; and during space walks.
Open Access
Hypercapnia in diving: a review of CO₂ retention in submersed exercise at depth.
(Undersea Hyperb Med, 2017-05) Dunworth, Sophia A; Natoli, Michael J; Cooter, Mary; Cherry, Anne D; Peacher, Dionne F; Potter, Jennifer F; Wester, Tracy E; Freiberger, John J; Moon, Richard E
Carbon dioxide (CO₂) retention, or hypercapnia, is a known risk of diving that can cause mental and physical impairments leading to life-threatening accidents. Often, such accidents occur due to elevated inspired carbon dioxide. For instance, in cases of CO₂ elimination system failures during rebreather dives, elevated inspired partial pressure of carbon dioxide (PCO₂) can rapidly lead to dangerous levels of hypercapnia. Elevations in PaCO₂ (arterial pressure of PCO₂) can also occur in divers without a change in inspired PCO₂. In such cases, hypercapnia occurs due to alveolar hypoventilation. Several factors of the dive environment contribute to this effect through changes in minute ventilation and dead space. Predominantly, minute ventilation is reduced in diving due to changes in respiratory load and associated changes in respiratory control. Minute ventilation is further reduced by hyperoxic attenuation of chemosensitivity. Physiologic dead space is also increased due to elevated breathing gas density and to hyperoxia. The Haldane effect, a reduction in CO₂ solubility in blood due to hyperoxia, may contribute indirectly to hypercapnia through an increase in mixed venous PCO₂. In some individuals, low ventilatory response to hypercapnia may also contribute to carbon dioxide retention. This review outlines what is currently known about hypercapnia in diving, including its measurement, cause, mental and physical effects, and areas for future study.
Open Access
Otorhinolaryngology and Diving-Part 1: Otorhinolaryngological Hazards Related to Compressed Gas Scuba Diving: A Review.
(JAMA otolaryngology-- head & neck surgery, 2018-03) Lechner, Matt; Sutton, Liam; Fishman, Jonathan M; Kaylie, David M; Moon, Richard E; Masterson, Liam; Klingmann, Christoph; Birchall, Martin A; Lund, Valerie J; Rubin, John S
Scuba diving is becoming increasingly popular. However, scuba diving is associated with specific risks; 80% of adults and 85% of juvenile divers (aged 6-17 years) have been reputed to have an ear, nose, or throat complaint related to diving at some point during their diving career. Divers frequently seek advice from primary care physicians, diving physicians, and otorhinolaryngologists, not only in the acute setting, but also related to the long-term effects of diving.The principles underpinning diving-related injuries that may present to the otorhinolaryngologist rely on gas volume and gas saturation laws, and the prevention of these injuries requires both that the diver is skilled and that their anatomy allows for pressure equalization between the various anatomical compartments. The overlapping symptoms of middle ear barotrauma, inner ear barotrauma, and inner ear decompression sickness can cause a diagnostic conundrum, and a thorough history of both the diver's symptoms and the dive itself are required to elucidate the diagnosis. Correct diagnosis and appropriate treatment result in a more timely return to safe diving.The aim of this review is to provide a comprehensive overview of otorhinolaryngological complications during diving. With the increasing popularity of diving and the frequency of ear, nose, or throat-related injuries, it could be expected that these injuries will become more common and this review provides a resource for otorhinolaryngologists to diagnose and treat these conditions.
Open Access
Pharmacologic Targeting of Red Blood Cells to Improve Tissue Oxygenation.
(Clin Pharmacol Ther, 2017-12-14) Reynolds, James D; Jenkins, Trevor; Matto, Faisal; Nazemian, Ryan; Farhan, Obada; Morris, Nathan; Longphre, John M; Hess, Douglas T; Moon, Richard E; Piantadosi, Claude A; Stamler, Jonathan S
Disruption of microvascular blood flow is a common cause of tissue hypoxia in disease, yet no therapies are available that directly target the microvasculature to improve tissue oxygenation. Red blood cells (RBCs) autoregulate blood flow through S-nitroso-hemoglobin (SNO-Hb)-mediated export of nitric oxide (NO) bioactivity. We therefore tested the idea that pharmacological enhancement of RBCs using the S-nitrosylating agent ethyl nitrite (ENO) may provide a novel approach to improve tissue oxygenation. Serial ENO dosing was carried out in sheep (1-400 ppm) and humans (1-100 ppm) at normoxia and at reduced fraction of inspired oxygen (FiO2 ). ENO increased RBC SNO-Hb levels, corrected hypoxia-induced deficits in tissue oxygenation, and improved measures of oxygen utilization in both species. No adverse effects or safety concerns were identified. Inasmuch as impaired oxygenation is a major cause of morbidity and mortality, ENO may have widespread therapeutic utility, providing a first-in-class agent targeting the microvasculature.
Open Access
Research report: Charcoal type used for hookah smoking influences CO production.
(Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc, 2015-07) Medford, Marlon A; Gasier, Heath G; Hexdall, Eric; Moffat, Andrew D; Freiberger, John J; Moon, Richard E
A hookah smoker who was treated for severe carbon monoxide poisoning with hyperbaric oxygen reported using a different type of charcoal prior to hospital admission, i.e., quick-light charcoal. This finding led to a study aimed at determining whether CO production differs between charcoals commonly used for hookah smoking, natural and quick-light. Our hypothesis was that quick-light charcoal produces significantly more CO than natural charcoal. A medium-sized hookah, activated charcoal filter, calibrated syringe, CO gas analyzer and infrared thermometer were assembled in series. A single 9-10 g briquette of either natural or quick-light charcoal was placed atop the hookah bowl and ignited. CO output (ppm) and temperature (degrees C) were measured in three-minute intervals over 90 minutes. The mean CO levels produced by quick-light charcoal over 90 minutes was significantly higher (3728 ± 2028) compared to natural charcoal (1730 ± 501 ppm, p = 0.016). However, the temperature was significantly greater when burning natural charcoal (292 ± 87) compared to quick-light charcoal (247 ± 92 degrees C, p = 0.013). The high levels of CO produced when using quick-light charcoals may be contributing to the increase in reported hospital admissions for severe CO poisoning.
Open Access
Sildenafil: Possible Prophylaxis against Swimming-induced Pulmonary Edema.
(Med Sci Sports Exerc, 2017-09) Martina, Stefanie D; Freiberger, John J; Peacher, Dionne F; Natoli, Michael J; Schinazi, Eric A; Kernagis, Dawn N; Potter, Jennifer VF; Otteni, Claire E; Moon, Richard E
Swimming-induced pulmonary edema (SIPE) occurs during swimming and scuba diving, usually in cold water, in susceptible healthy individuals, especially military recruits and triathletes. We have previously demonstrated that pulmonary artery (PA) pressure and PA wedge pressure are higher during immersed exercise in SIPE-susceptible individuals versus controls, confirming that SIPE is a form of hemodynamic pulmonary edema. Oral sildenafil 50 mg 1 h before immersed exercise reduced PA pressure and PA wedge pressure, suggesting that sildenafil may prevent SIPE. We present a case of a 46-yr-old female ultratriathlete with a history of at least five SIPE episodes. During a study of an exercise submerged in 20°C water, physiological parameters before and after sildenafil 50 mg orally were as follows: O2 consumption 1.75, 1.76 L·min; HR 129, 135 bpm; arterial pressure 189/88 (mean 121.5), 172/85 (mean 114.3) mm Hg; mean PA pressure 35.3, 28.8 mm Hg; and PA wedge pressure 25.3, 19.7 mm Hg. She has had no recurrences during 20 subsequent triathlons while taking 50 mg sildenafil before each swim. This case supports sildenafil as an effective prophylactic agent against SIPE during competitive surface swimming.
Open Access
Successful treatment of pneumatosis intestinalis with associated pneumoperitoneum and ileus with hyperbaric oxygen therapy.
(BMJ case reports, 2017-05-30) Calabrese, Evan; Ceponis, Peter Jm; Derrick, Bruce J; Moon, Richard E
Pneumatosis intestinalis (PI), or the presence of air in the bowel wall, is a rare disorder that is associated with a variety of underlying diseases, including connective tissue disorders. PI presents on a spectrum from asymptomatic to bowel obstruction and acute abdomen. In general, treatment of PI consists of treating the underlying disease. Both normobaric and hyperbaric oxygen have been used to treat PI directly. Here we report a symptomatic scleroderma-related case of PI that responded clinically to hyperbaric oxygen therapy. This report adds to a growing body of literature supporting a role for hyperbaric oxygen therapy in symptomatic PI.
Open Access
The Dewey monitor: Pulse oximetry can independently detect hypoxia in a rebreather diver.
(Undersea Hyperb Med, 2017-11) Lance, Rachel M; Natoli, Michael J; Dunworth, Sophia AS; Freiberger, John J; Moon, Richard E
Rebreather diving has one of the highest fatality rates per man hour of any diving activity in the world. The leading cause of death is hypoxia, typically from equipment or procedural failures. Hypoxia causes very few symptoms prior to causing loss of consciousness. Additionally, since the electronics responsible for controlling oxygen levels in rebreathers often control their alarm systems, frequently divers do not receive any external warnings. This study investigated the use of a forehead pulse oximeter as an independent warning device in the event of rebreather failure. Ten test subjects (seven male, three female, median age 29, range 26-35) exercised at a targeted rate of 2 L/minute oxygen consumption while on a non-functional rebreather breathing loop (mean consumption achieved 2.09 ± 0.36 L/minute). Each subject was tested both at the surface and at pressurized depth of 77 fsw (starting pO₂=0.7 atm). The data show that a pulse oximeter could be used to provide an Mk 16 rebreather diver with a minimum mean of 49 seconds (± 17 seconds SD) of warning time after a noticeable change in blood oxygen saturation (SpO₂ ≤ 95%) but before any risk of loss of consciousness (calculated SpO₂ ≤ 80%), so that the diver may take mitigating actions. No statistical difference in warning time was found between the tests at surface and at 77 fsw (P=0.46).