1
|
Lee DJ, Matthews PGD. Oxygen extraction efficiency of the tidally-ventilated rectal gills of dragonfly nymphs. Proc Biol Sci 2024; 291:20231699. [PMID: 38264780 PMCID: PMC10806436 DOI: 10.1098/rspb.2023.1699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/18/2023] [Indexed: 01/25/2024] Open
Abstract
Dragonfly nymphs breathe water using tidal ventilation, a highly unusual strategy in water-breathing animals owing to the high viscosity, density and low oxygen (O2) concentration of water. This study examines how well these insects extract O2 from the surrounding water during progressive hypoxia. Nymphs were attached to a custom-designed respiro-spirometer to simultaneously measure tidal volume, ventilation frequency and metabolic rate. Oxygen extraction efficiencies (OEE) were calculated across four partial pressure of oxygen (pO2) treatments, from normoxia to severe hypoxia. While there was no significant change in tidal volume, ventilation frequency increased significantly from 9.4 ± 1.2 breaths per minute (BPM) at 21.3 kPa to 35.6 ± 2.9 BPM at 5.3 kPa. Metabolic rate increased significantly from 1.4 ± 0.3 µl O2 min-1 at 21.3 kPa to 2.1 ± 0.4 µl O2 min-1 at 16.0 kPa, but then returned to normoxic levels as O2 levels declined further. OEE of nymphs was 40.1 ± 6.1% at 21.3 kPa, and did not change significantly during hypoxia. Comparison to literature shows that nymphs maintain their OEE during hypoxia unlike other aquatic tidal-breathers and some unidirectional breathers. This result, and numerical models simulating experimental conditions, indicate that nymphs maintain these extraction efficiencies by increasing gill conductance and/or lowering internal pO2 to maintain a sufficient diffusion gradient across their respiratory surface.
Collapse
Affiliation(s)
- Daniel J. Lee
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z4
| | - Philip G. D. Matthews
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z4
| |
Collapse
|
2
|
Viswanath R, Pulickal R, Chirayath JJ, Mullapilly K. Comparison of vital capacity rapid inhalation and tidal ventilation induction with sevoflurane in adults: a prospective cohort study. Med Gas Res 2021; 11:100-103. [PMID: 33942779 PMCID: PMC8174405 DOI: 10.4103/2045-9912.314328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Vital capacity rapid inhalation induction (VCRII) results in faster achievement of desired minimum alveolar concentration while reducing the incidence of excitatory phenomenon compared to conventional incremental technique. This study aimed to determine whether the VCRII can achieve faster induction of anesthesia in adults compared to the traditional tidal ventilation (TV) technique. Following the approval from the Institutional Ethics Committee, Amala Institute of Medical Sciences, with an approval No. AIMSIEC/07/2017, on July 1, 2017, 51 adults belonging to American Society of Anesthesiologists physical status I–II, undergoing elective surgery at a tertiary care teaching hospital were prospectively assigned to two groups: 25 in VCRII (38.3 ± 13.3 years old, 20 (80%) females) and 26 in TV inhalation induction (35.2 ± 11.9 years old, 17 (65%) females) using 8% sevoflurane in 66% nitrous oxide. The induction time, such as time (in seconds) to the cessation of voluntary finger tapping, time to loss of eyelash reflex, time to return of regular breathing, the return of conjugate gaze, was measured. The primary outcome was time to induction as defined by time to loss of eyelash reflex. Hemodynamic effects of both methods were compared at baseline and 1, 3, 5, 10, 15-minute intervals from induction. Induction was significantly faster in the VCRII group compared with the TV group in all the measured parameters. Hemodynamic parameters were comparable in both the groups. VCRII resulted in a faster induction time compared to the TV technique in adults.
Collapse
Affiliation(s)
- Renjith Viswanath
- Department of Anaesthesiology, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| | - Raghavan Pulickal
- Department of Anaesthesiology, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| | - Joe John Chirayath
- Department of Anaesthesiology, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| | - Kesavan Mullapilly
- Department of Anaesthesiology, Amala Institute of Medical Sciences, Thrissur, Kerala, India
| |
Collapse
|
3
|
Atkins WK, McDougall R, Perkins EJ, Pereira-Fantini PM, Tingay DG. A dedicated respiratory function monitor to improve tidal volume delivery during neonatal anesthesia. Paediatr Anaesth 2019; 29:920-926. [PMID: 31318466 DOI: 10.1111/pan.13707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 07/07/2019] [Accepted: 07/12/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Tight control of tidal volume using accurate monitoring may improve neonatal outcomes. However, respiratory function monitors incorporated in current anesthetic workstations are generally inaccurate at tidal volumes used for infants. AIMS To determine if a specific respiratory function monitor for neonatal infants improved expired tidal volume delivery during anesthesia. METHOD Infants <3 months old requiring intubation for surgery in the operating theater were studied. After intubation a Phillips NM3, Acutronic Florian, or Novametrix Ventcheck Respiratory Function Monitor was integrated into the circuit, and clinicians given access to the display for the duration of anesthesia. Breath-to-breath expired tidal volume delivery, leak, and delivered pressure were recorded, with cardiorespiratory parameters. These were compared with a matched control group with clinicians blinded to respiratory function monitor display. RESULTS A total of 10 055 and 2569 inflations were measured in the respiratory function monitor visible (n = 32) and masked (n = 33) groups, respectively, with mean (standard deviation) delivered expired tidal volume 7.5 (2.4) mL/kg and 7.7 (3.0) mL/kg, respectively; mean difference (95% confidence interval) -0.2 (-1.1, 0.8) mL/kg (Welch's t test). In the visible group, 55.6% of expired tidal volumes were between 4 and 8 mL/kg compared to 51.7% in the masked group; relative benefit (95% confidence interval), 1.08 (1.03, 1.12). Expired tidal volume was less likely to be <4 mL/kg in the visible group compared to masked group; 6.4% vs 9.8%, 1.53 (1.33, 1.76). The use of a respiratory function monitor also reduced the number of inflations >10 mL/kg; 13.0% vs 22.0%, 1.11 (1.09, 1.14). CONCLUSION Tidal volumes <4 mL/kg and >10 mL/kg are frequently delivered during neonatal anesthesia. The inclusion of an accurate respiratory function monitor may reduce the risk of exposure to potentially harmful tidal volumes.
Collapse
Affiliation(s)
- William K Atkins
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, University of Melbourne, Parkville, Vic., Australia
| | - Rob McDougall
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, University of Melbourne, Parkville, Vic., Australia.,Department of Anaesthesia, The Royal Children's Hospital, Parkville, Vic., Australia
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Neonatology, The Royal Children's Hospital, Parkville, Vic., Australia
| | - Prue M Pereira-Fantini
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, University of Melbourne, Parkville, Vic., Australia
| | - David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, University of Melbourne, Parkville, Vic., Australia.,Department of Neonatology, The Royal Children's Hospital, Parkville, Vic., Australia
| |
Collapse
|
4
|
Retory Y, de Picciotto C, Niedzialkowski P, Petitjean M, Bonay M. Body Mass Index-Dependent Ventilatory Parameters From Respiratory Inductive Plethysmography During 6-Minute Walk Test. Respir Care 2016; 61:521-8. [PMID: 26814221 DOI: 10.4187/respcare.04426] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Walking is part of obesity management. Assessment of ventilatory impairments and consequences for gait induced by obesity could be clinically helpful. We aimed to develop a method to accurately monitor ventilation with respiratory inductive plethysmography (RIP) in subjects with high body mass indices (BMIs) during a 6-min walk test (6MWT). METHODS 25 volunteers were divided into 2 groups based on BMI (<25 or >30 kg/m2) and performed a 6MWT with a calibrated RIP. Ventilatory parameters (tidal volume [V(T)], inspiratory [T(I)] and expiratory [T(E)] times, V(T)/T(I) ratio, and T(I)/Ttot ratio) were determined after processing RIP signals with a custom-made algorithm designed to discriminate tissue motion artifacts and respiratory cycles in the time domain. Six-min walk distance and average speed by minute were collected. RESULTS The number of artifacts removed by the algorithm used for artifact removal was higher for high-BMI subjects and was correlated to their individual values (r = 0.66, P < .001). Six-min walk distance was lower for the group with a higher BMI (P = .001). ANOVA revealed effects of exercise for V(T), T(I), and T(E) (P < .001) and also BMI effects in the course of the 6MWT for V(T), T(I), T(E), V(T)/T(I), and T(I)/Ttot (P < .001 for each of them). CONCLUSIONS This respiratory monitoring method is sufficiently sensitive to point out differences between rest and exercise as well as locomotor and ventilatory differences relative to BMI during the 6MWT. Thus, this system gives useful information from the 6MWT for clinicians who want to assess respiratory patterns of patients during this commonly used test.
Collapse
Affiliation(s)
- Yann Retory
- Université de Versailles Saint-Quentin en Yvelines, UFR des Sciences de la Santé, Montigny-le-Bretonneux, France, U1179 Inserm, Laboratoire de Physiologie TITAN, Montigny-le-Bretonneux, France, and Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France.
| | - Carole de Picciotto
- Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France
| | - Pauline Niedzialkowski
- Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France
| | - Michel Petitjean
- Université de Versailles Saint-Quentin en Yvelines, UFR des Sciences de la Santé, Montigny-le-Bretonneux, France, U1179 Inserm, Laboratoire de Physiologie TITAN, Montigny-le-Bretonneux, France, and Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France
| | - Marcel Bonay
- Université de Versailles Saint-Quentin en Yvelines, UFR des Sciences de la Santé, Montigny-le-Bretonneux, France, U1179 Inserm, Laboratoire de Physiologie TITAN, Montigny-le-Bretonneux, France, and Service de Physiologie-Explorations Fonctionnelles, Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Paris Ile-de-France Ouest, Boulogne-Billancourt, France
| |
Collapse
|
5
|
Clifton L, Clifton DA, Hahn CEW, Farmeryy AD. A Non-Invasive Method for Estimating Cardiopulmonary Variables Using Breath-by-Breath Injection of Two Tracer Gases. IEEE J Transl Eng Health Med 2013; 1:1900108. [PMID: 27170849 PMCID: PMC4819233 DOI: 10.1109/jtehm.2013.2268158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 03/25/2013] [Accepted: 05/21/2013] [Indexed: 11/07/2022]
Abstract
Conventional methods for estimating cardiopulmonary variables usually require complex gas analyzers and the active co-operation of the patient. Therefore, they are not compatible with the crowded environment of the intensive care unit (ICU) or operating theatre, where patient co-operation is typically impossible. However, it is these patients that would benefit the most from accurate estimation of cardiopulmonary variables, because of their critical condition. This paper describes the results of a collaborative development between an anesthesiologists and biomedical engineers to create a compact and non-invasive system for the measurement of cardiopulmonary variables such as lung volume, airway dead space volume, and pulmonary blood flow. In contrast with conventional methods, the compact apparatus and non-invasive nature of the proposed method allow it to be used in the ICU, as well as in general clinical settings. We propose the use of a non-invasive method, in which tracer gases are injected into the patient's inspired breath, and the concentration of the tracer gases is subsequently measured. A novel breath-by-breath tidal ventilation model is then used to estimate the value of a patient's cardiopulmonary variables. Experimental results from an artificial lung demonstrate minimal error in the estimation of known parameters using the proposed method. Results from analysis of a cohort of 20 healthy volunteers (within the Oxford University Hospitals NHS Trust) show that the values of estimated cardiopulmonary variables from these subjects lies within the expected ranges. Advantages of this method are that it is non-invasive, compact, portable, and can perform analysis in real time with less than 1 min of acquired respiratory data.
Collapse
Affiliation(s)
- Lei Clifton
- University of Oxford Department of Engineering Science Institute of Biomedical Engineering Oxford U.K
| | - David A Clifton
- University of Oxford Department of Engineering Science Institute of Biomedical Engineering Oxford U.K
| | - Clive E W Hahn
- University of Oxford Nuffield Department of Clinical Neurosciences Nuffield Division of Anaesthetics Oxford U.K
| | - Andrew D Farmeryy
- University of Oxford Nuffield Department of Clinical Neurosciences Nuffield Division of Anaesthetics Oxford U.K
| |
Collapse
|