There have been a number of studies regarding the use of oxygen in the postoperative period and its beneficial effects on the surgical patient (1–7). Supplemental oxygen is required to compensate for expiration of anesthetic gases, diffusion hypoxia, and decreased respiratory rate and volume. Facemasks and nasal cannulae are currently used to provide the necessary high oxygen concentrations. These devices, although effective, are associated with certain problems owing to their structure (8–10). This article describes a clinical study using the OxyArm™ oxygen delivery device (Southmedic, Inc.) in postoperative patients emerging from general anesthesia. The OxyArm™ is a low-flow oxygen delivery device that does not enclose the mouth and nostrils as a mask does and yet delivers large concentrations of oxygen (6). The OxyArm™ comfortably attaches to the patient's head, much like a telephone headset, and delivers oxygen to the nose and mouth simultaneously from a patented diffuser. Oxygen flows through tubing in the headset and is distributed over the patient's face as an “oxygen cloud” (Figure 1). On inspiration, this concentrated oxygen cloud is the source of the gas inspired during inspiration.
To evaluate this device at a major medical center, we continuously recorded oxygen saturation from patients emerging from general anesthesia and solicited nurse and patient evaluations using a questionnaire.
With medical center operating room (OR) committee and IRB approval, 60 patients selected in consecutive order of surgery scheduling in the recovery room, were studied. It was affirmed by the IRB that we did not need to obtain patient permission. A broad spectrum of patient types, ages, and surgical procedures were evaluated, including ASA IV and morbidly obese patients. OxyArm™ oxygen administration began in the OR immediately after extubation of the trachea and continued into the postanesthesia care unit (recovery room) for a period of 30 min. The OxyArm™ diffuser was positioned 2 cm from the nostrils and mouth in accordance with company recommendations. Each patient was monitored with a pulse oximeter probe (Radical, Masimo) placed on the third digit of the hand opposite the extremity used for blood pressure readings. Oxygen saturation values were recorded continuously at 10-s intervals and were later imported into a computer for analysis. Oxygen was administered at 4 L/min (0.32–0.35 Fio2) (11) for the first 4 min before and after extubation and then was reduced to 2 L/min (0.28–0.31 Fio2) (11) for the remainder of the study. Oxygen saturation levels were compared using unpaired Student's t-tests assuming unequal variances at 3 separate time frames: 1) before extubation (last recorded saturation before extubation), 2) at 4 L oxygen/minute (4 min after extubation), and 3) 2 L oxygen/minute (8 min after extubation).
Sixty questionnaires were administered to nursing staff and patients. The questionnaire was comprised of 12 questions regarding the perceived efficacy, comfort, and safety of the OxyArm™ during recovery.
All 60 patients completed the study. There was no saturation level less than 85% (defined as hypoxia) at any time for these 60 patients (lowest value was 88%). The saturation before tracheal extubation was 98.02% ± 1.42% (mean ± sd), which was not different from the saturation with the OxyArm™ at the 4 L/min (97.95% ± 3.09%; P = 0.88) or 2 L/min (97.88% ± 2.63%; P = 0.73) (Figure 2). There were three episodes of emesis in the recovery room that were treated without interrupting oxygen administration. Eight patients in the study who were morbidly obese with significant reductions in functional residual capacity had no episodes of hypoxia with OxyArm™ oxygen administration. There were no OxyArm™-related complications with any patient.
Fifty-six questionnaires were returned; the patients completed nine and the rest were completed by hospital nursing staff. Physician and nursing staff comments revealed that this new device was well received by both hospital staff and patients. Nine of 11 patients who were sufficiently awake at the end of the test period to respond to the questionnaire were not aware that they had the device in place. One patient stated that the headband securing the OxyArm™ was too tight; this problem was modified with a small piece of foam. Recovery room nurse comments were overwhelmingly positive. The most common nursing response was that there was improved patient communication without interrupting the oxygen flow as compared with the oxygen mask. Nurses also reported that they were able to accomplish oral hygiene and temperature monitoring without having to remove the OxyArm™.
Simple oxygen masks have limited efficacy in the average patient because the volume under the mask is small (typically 40 mL) and considerable room air is entrained during inspiration. Oxygen masks with reservoir bags are used to deliver larger inhaled oxygen concentrations. All such masks enclose the face, which poses a hazard if the patient vomits (increasing the potential for aspiration) or if the mask becomes disconnected from the fresh gas source (resulting in hypercarbia and hypoxia). Moreover, oxygen administration is interrupted when patients remove the mask because of claustrophobia or if the mask is removed for nursing interventions. Nasal cannulae have limited efficacy because there is no regular evaluation of patients to determine whether they are nose or mouth breathers. The effect of narcotics and postsurgical sedation also affect the nasal cannula delivery (12). There have been anecdotal reports from nursing staff of nasal mucosal trauma resulting from the use of nasal cannulae (8–10).
Video monitoring of postsurgical patients has shown that supplemental oxygen is not delivered consistently in the immediate postoperative period because of manipulation and removal of these devices by both patients and nurses for feeding, talking, oral hygiene, and general discomfort (3). The average oxygen saturation decreased 4% during removal of the mask or cannula. This study demonstrates that supplemental oxygen can be effectively administered with the OxyArm™ to prevent oxygen desaturation in the early postoperative period. Oxygen saturation was monitored with a second generation pulse oximeter that is resistant to motion-induced artifact that can occur during transfer of the patient from the OR table to the recovery room bed (12–23).
Nurse and patient evaluations of the device were overwhelmingly positive. Our findings of patient compliance and comfort with the OxyArm™ in this large study, as also noted by Paul et al. (24), is another of its significant advantages over oxygen masks and nasal cannulae. Because of claustrophobic and discomfort complaints with masks and nasal cannulae, there is clinical evidence to show that the physician-supplemental oxygen order is often not complied with on the ward because these devices are removed for other treatment procedures. Video monitoring of patients in this setting showed that, as a result of patient removal and nursing staff removal for therapeutic reasons, significant oxygen desaturations of these oxygen-dependent patients was noted (3). However, the structural advantages of the OxyArm™ eliminate the complications associated with mask and nasal cannulae (10), some of which can result in significant complications including aspiration after emesis into masks, hypoxia and hypercarbia secondary to oxygen mask source disconnects, and mucosal irritation, bleeding, and pain caused by nasal cannulae.
Because this study did not have a control group in which conventional oxygen therapy was used, there remains a need for additional studies that directly compare the efficacy and safety of the OxyArm™ with standard oxygen masks and nasal cannulae. Also, a study of the OxyArm™ in the chronic home care setting could investigate whether lower oxygen flows/minute could result in cost savings in the fixed insurance environment.
We conclude that the OxyArm™ has proven to be representative of the next generation of oxygen administration devices, offering large concentrations of supplemental oxygen therapy to patients without the complications of older devices and with great patient compliance and comfort (Figs. 1 and 2).
The authors would like to thank the Cedars-Sinai Medical Center PACU nursing staff, Kaiser Permanente Medical Center Bellflower Library staff, Mike Petterson – Masimo Inc., for oximeter technical assistance, Sandra Ramirez for technical manuscript assistance, and Leslie Dodson for revision assistance. Thanks also to Joseph A. Orth, MS, for his statistical analysis assistance in this study.
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