ABG and other results - what do they mean?

Arterial Blood Gas
12-11-2008
Draw time 0101
FIO2/LF .21
PaO2 75
PaCO2 45
pH 7.40
Hb 14.7
HbO2 93.6
HbCO 0.9
HvMet 1.2

Dr. gave me some tests sitting in a booth. I do not have detailed results although she said I was above average on all for age/weight/height. Tests were:
RESP FLOW VOLUME LOOP
CO DIFF. CAP
MEASURED AIRFLOW RESISTANCE
RESIDUAL CAPACITY

In a letter to me Dr. she wrote the following-
Your patient had a sleep study performed at ------- on 12/10/2008. The patient was previously diagnosed with obstructive sleep apnea syndrome and is currently using nasal CPAP with a variable rate (12 to 16cm of water pressure). During the urrent study he was initially evaluated eithout therapy. Severe apnea is noted with 51 apneas per hour of sleep and he desaturated to 78%. Rem sleep is not present during the baseline portion of the recording so overall apnea severity may be underestimated. CPAP was initiated at 12cm and titrated to 15cm. At 15cm of water pressure using a medium Swift LT mask,heated humidity and a chinstrap as well as C-Flex at a setting of 3,respiratory events were effectively resolved. No adjustments were made to his CPAP machine as his current pressure appears to be adequate. However he will need to have heated humidity and a chinstrap added to his home CPAP setup. If his current machine does not have C-Flex,we recommend that he be setup wit a machine that does since he is complaining of gastric insufflations causing "major stomache pain due to air in his stomache in the mornings". This should certainly help. If problems persist he may need an alternate PAP device. Also of note,his ABGs did show hypoxemia and he expresses multiple concerns in his questionnaire,so a pulmonary workup,if not already done,may be helpful. This is a somewhat complex case and he does have multiple concerns noted on his sleep questionnaire and it may be helpfull in this case for him to follow up up with a board certified sleep specialist. We would certainly be happy to see him in our office to help address these complaints. He is sleepy during the day so he should be cautioned with regard to driving until his sleepiness is resolved.

The end - This letter is full of holes. I didnt complain of daytime sleepiness while on CPAP. I brought in a M-series APAP with humidifier and my own Papcap 2 so I obviously have these and Cflex. I already had an appointment in this DR's office scheduled. I went to the appointment and was tested as written above. ABG was done the night of the study just before. Dr. said to come back and see her RN,CS,FNP in 3 months and to see her again in 9 months and if I have any issues to call. Also set me up with a DME to help fit me for a mask and chin strap and I looked today and the DME isn't even on my insurance,no wonder they haven't called. This is why I hate dealing with Dr's.

My report does show the following :
Total sleep 351 100%
N1 241 68.4%
N2 62.5 17.8%
Slow Wave 0 0%
REM 47.5 13.5%


Sleep latency 28.5 minutes
REM latency 330 minutes
# of Arousals 161
WASO: 70.0 minutes
Positional effect = No
Arrhythmias = No
Sleep eff: 78.1%

Periodic movements = NONE

Respiratory Analysis:
---------------------
(226.5 Minutes)
Obstructive 134
Central 1
Mixed 58
Total# of events 193
AHI 51
REM AHI = N/A
Low SpO2: 78%
Mean SpO2: 93%
Time below 88%: 20.7 minutes

CPAP Analysis
--------------------
(15cm H20,56.5 Minutes)
Obstructive 0
Central 4
Mixed 0
Totl events = 4
AHI = 4
Rem AHI = 0
Low SpO2 = 93%
Mean SpO2 = 96%
Time below 88% = 0

Technician comments:
The patient slept laterally and supine. Respiratory events were seen. CPAP was started at 12cm H2O and increased to 15 cm H2O with C-Flex of 3. A Resmed Swift mask was used. Heated humidity and chin strap were added for leaks. No PLMs or arrhythmias were noted.Patients CPAP machine was verified at 12-16 cm H2O. No adjustments were made.

Physician interpetation:
1)The patient was monitored for 7 hours 30 minutes during which 5 hours and 51 minutes of sleep was recorded. The patient slept 3 hours and 47 minutes while documenting sleep apnea/hypopnea(110 minutes supine) and 57 minutes while using CPAP at 15cm H2O (44 minutes supine).
2)Sleep architecture is disturbed with an increase in light sleep (stage N1),decreased REM and anabsence of slow wave sleep.
3) Severe sleep apnea/hypoapnea is present with 51 events per hour of sleep. Arterial oxygen desaturation to 78% is associated with these events.
4) CPAP at 15 cm H2O controls the patients documented sleep apnea/hypoapnea with 4 events per hour of sleep.

MY NOTE - I put on PAPCAP/Chin strap when I was placed on CPAP and heated humidity was apparent from the start..... Edit : Less than 1 hour on Cpap and the first hour or more at home on Cpap is usually my best so probably not good results.

I'm not real good on what the various reported results of the ABG (arterial blood gases) mean. HOWEVER, overnight oximetry is NOT as efficient at measuring your 02 levels as an ABG. For instance, a smoker will measure a higher 02 saturation than actual due to the oximeter reading C02 (I think that is the right one) and 02 as 02 saturation whereas the ABC can differentiate between percentages of 02 and of C02 in the blood.

What is really confusing to me is that I am under the impression that a full PFT (pulmonary function test) done "in the booth" as compared to "just" a spirometry could also detect and differentiate the amount of C02 retention.

The overnight oximetry done during your titration did not report any 02 desaturations and the pulmonologist interpreting your PFT saying your results were normal would substantiate your sleep evaluation results.

I"m obviously outta my league here! And corn-fused as you are.

... since he is complaining of gastric insufflations causing "major stomache pain due to air in his stomache in the mornings". This should certainly help. If problems persist he may need an alternate PAP device. Also of note,his ABGs did show hypoxemia ...

It is aggravating when you provide the information or equipment and the doctors pay no attention to it when they do their dictation. It certainly lessens your confidence in their ability and their attention to detail when they ignore what should be the obvious. I've run into this repeatedly thru the years w/doctors. I'm 5'4" and weigh 112 lbs and a sleep pulmo put on his dictation that I should consider losing weight!!!! How much confidence in and respect for that doctor do you think I had??? However, it would appear that she is suggesting that a step up from your APAP to a more sophisticated xPAP might be indicated to alleviate the aerophagia.

At least this is my take on the information you've provided. What do I know? I'm just a patient!!!

Bump for any bored Respiratory Techs out there . Is my ABG good ?

kinda bored today So, here goes....

Arterial Blood Gas
12-11-2008
Draw time 0101
FIO2/LF .21
PaO2 75
PaCO2 45
pH 7.40
Hb 14.7

This is a perfectly normal ABG; although the CO2 is on the upper level of normal. The value for your HCO3 (bicarb) BE (base excess) were not given...this would give more info. The range for a normal ABG is:
pH: 7.35-7.45
CO2: 35-45
HCO3: 22-26
PaO2: 70-100 (depending on age & history)

RRT in GA

Just a quick Thank You Peach64. I gave up on an answer long ago. But Thanks .

peach64 wrote:The value for your HCO3 (bicarb) BE (base excess) were not given...this would give more info.

RRT in GA

Those are "calculated" parameters, so they can easily be determined utilizing given information and Henderson-Hasselbach (is it really supposed to be Henderson-Hasselbalch?) so

-HCO3 = 26.9
BE = +2.3

SAG